Physiology Dr.Guy's

45% cells, 55% plasma

erythrocyte (RBC - 4.8 to 5.4 million/cubic mm), leukocyte (WBC - 5000 to 9000), thrombocyte (250,000 to 400,000)

Neutrophils (granular - 60%), Eosinophils (granular - 3%), Basophils (granular - 0%), Lymphocytes (agranular - 30%), Monocytes (agranular - 8%)

water (91.5%), proteins (7%) (albumin is 55% - maintains osmotic pressure, globulin is 38% - antibodies and fibrinogen is 7% - role in blood clotting)

hematopoiesis (formation of blood cells) in yolk sac of embryo/fetus then liver and spleen then red bone marrow in adults

partial pressure of oxygen

formation of RBC's in bone marrow, low partial pressure of oxygen in blood in kidney stimulates the production of erythropoietin (80% made in extraglomerular mesagium, 20% made in lever)

low blood volume, anemia, low hemoglobin, poor blood flow, pulmonary disease

large, nucleated, immature cells which develop into the 5 major types of blood cells

• Rubriblast --> reticulocyte --> erythrocyte
• Myeloblast --> neutrophils, eosinophils, basophils
• Megakaryoblast (megakaryocyte) --> thrombocyte (platelet)
• Lymphoblast --> lymphocytes
• Monoblast --> monocytes

erythropoeitin, rubriblast still has a nucleus, reticulocyte contains some hemoglobin but no necleus

anucleated mature RBC, contains hemoglobin, life span = 120 days

transports oxygen (oxy Hb to body from lungs), transports carbon dioxide (carboxy Hb to lungs from body) as HCO₃^-

4 protein chains or subunits (2 alpha and 2 beta), each containing a heme group with one iron, which can bind 1 oxygen each (hemoglobin can bind 4 oxygen)

• ferrous - Fe²⁺ form it is absorbed and carried in hemoglobin
• ferritin - Fe³⁺ storage form
• transferrin - Fe³⁺ blood transport

leukocytes are nucleated and do not contain hemoglobin

• PMN's which develop from red bone marrow
• Basophils - heparin (vasodilator), tissue inflammation, hypersensitivity, histamine
• Eosinophils - allergic reactions, parasitic worms
• Neutrophils - bacterial antibiotic activity, phagocytic
• "BEN G"

• MN's that develop from lymphoid tissue
• Lymphocytes - viral, production of antibodies
• B cells - produced in bone marrow, when they contact an antigen they are converted to plasma cells --> produce antibodies
• T cells - differentiated in the thymus, release chemicals which stimulate macrophages to migrate toward infects
• Monocytes - chronic infections, macrophage production, antibiotic reactions

neutrophil (blood), macrophage (tissue - particularly in inflammation reactions, there are no macrophages in the blood)

• Intrinsic - intravascular, occurs in minutes, contact with collagen - XII, XI, IX, VIII
• Extrinsic - interstitial, occurs in seconds, tissue thromboplastin - VII, III
• Common - X, V, II, I

prothrombin (II), VII, christmas factor(IX), stuart factor (X)

II

recipient = AB+, donor = O-

antigen is a chemical introduced into the body, body reacts by producing antibodies (protein that combines specifically with the antigen) or T cells

T cells, direct immunity against fungus, parasites, viral, cancer, tissue implants

B cells, antibodies, indirect against bacterial and viral infections

macrophage binds with the antigen and presents in to the T cell (can only recognize antigen if presented by macrophage), also produces lymphokines (interleukin and interferon)

• Cytotoxic - attach to invading cell and secrete lymphotoxins (to kill antigen directly) or lymphokinins (to kill antigen indirectly)
• Helper - work with B cells to amplify antibody production, release lymphokinin which stimulate killer T cells
• Memory - programmed to recognize original invading agen for an accelerated response to 2nd exposure
• Suppressor - damplen the immune response several weeks after infection

• Macrophages - interleukin I
• Cytotoxic cells - interleukin II
• Helper - interleukin II

an antigen is processed by macrophage and presented to the B cell which induces B cell proliferation and differentiation

formed and mature in bone marrow, differentiate in spleen

Plasma cells (secrete antibodies), memory cells

• gamma globulins
• IgG - most abundant, protects against bacteria and virus, crosses the placenta, "Gee thanks mom"
• IgA - provides local protection on mucous membranes (saliva, vitamin A)
• IgM - first to appear after intitial exposure to antigen on B cell surface, largest
• IgD - stimulate antibody production
• IgE - allergic reactions on mast and basophil cells and parasitic infections (along with eosinophils)

portion of antigen determining specificity

caused by sensitized lymphocytes (IgE)

severe local inflammatory reaction on blood vessels

localized anaphylaxis (hives)

allergic hypersensivity reaction

stimulate phagocytes

attraction of cells to a chemical source

movement of leukocytes through blood vessel walls

make your own antibodies (long term) after an unintentional exposure (ex. you get a cold)

received from mom, short term (IgG)

Injected with virus, body produces antibodies (long term)

Injection of antitoxin or antibodies

• Tricuspid - between Right atria and ventricle
• Bicuspid - mitral - between left atria and ventricle
• "Ride a Tricycle before you Learn to ride a Bicycle"

autonomic nervous system increases or decreases the heart rate, the actual contraction is intiated within the heart

the ability of the heart to spontaneously and rhythmically generate action potentials

Sinoatrial node (SA) --> internodal pathway --> atrioventricular node (AV) - slowest --> Bundle of his --> left and right branch --> purkinje fibers - fastest

pacemaker of the hear, initiates contractions, located in the right atrium, leaky sodium channels (high permeability), causes depolarization of cardiac tissue

located at the lower right atrium, depolarized by the impulse initiated at the SA node, delay in transmission (allows time for the atria to empty into the ventricles), becomes the pacemaker if the SA node is damaged

runs within the interventricular septum, causes conduction of the ventricles, terminate as purkinje fibers

atrial depolarization, spread from SA node through two atria, an enlarged P wave indicates an enlarged atria

Ventricular depolarization, enlarged Q wave indicates a myocardial infarction (MI), enlarged R wave indicates ventricular enlargement

ventricular repolarization

small rise in blood pressure that occurs with closing of the aortic valve

phase of contraction = systole, phase of relaxation = diastole

bicupsid on left and tricuspid on right (closed during systole of ventricles)

aortic on left and pulmonic on right (open during ventricular systole

atrial systole --> isovolumetric contraction --> ejection period --> isovolumetric relaxation --> ventricular filling --> atrial systole

both atria contract, blood flows from the atria to the ventricles, contraction of the atria causes the S4 heart sound, semilunar valves are closed, AV valves are open

30% of blood, at end pressure in the ventricles becomes greater than the pressure in the atria causing the AV valves to slam shut causing the S1 heart sound

rise in ventricular pressure, All valves are closed --> there is no change in volume (isovolumetric - volume stays the same), at the end the pressure in the ventricles becomes greater than the pressure in the pulmonic artery and aorta

phase begins with the opening of the semilunar valves, AV valves remain closed, ventricles empty into systemic and pulmonic circulation, pressure in the pulmonic artery and aorta causes the semilunar valves to shut (S2 sound), this phase is marked by a drop in ventricular pressure and a rise in pulmonic and systemic pressure

All valves are closed, dicrotic notch appears during this phase (brief rise in aortic pressure during the T wave), atria fill with blood, at the end pressure in the atria becomes greater than the pressure in the ventricles --> AV valves open

begins with the opening of the AV valves, 70% of blood enters from atria even though they have not contracted yet, increased diastolic pressure, S3 heart sound occurs when blood enters ventricles

the amount of blood pumped by either ventricle per minute = Stroke volume (SV - amount of blood pumped per contraction) X Heart rate (HR - number of beats per minute)

• End systolic volume - amount of blood remaining in a ventricle following systole (determined by atrial pressure and force of ventricular contraction
• High ESV = low SV
• End diastolic volume - amount of blood remaining in the ventricle after diastole (determined by length of ventricular diastole and venous pressure)
• High EDV = High SV

what flows in must flow out (CO depends on venous return) - as cardiac muscle fibers are stretched a greater contraction is generated

the body's principal mechanism of short term control over cardiac output and blood pressure, controlled by the inhibitory effects of the parasympathetic nerves and the stimulating effects of the sympathetic nerves

groups of neurons in the medulla oblongata which regulate heart rate and blood vessel diameter (cardioacceleratory and cardioinhibitory center), stimulated by higher brain regions, baroreceptors (carotid sinus and aortic sinus) and chemorepectors (carotid body and aortic body)

sympathetic fibers which innervate the SA node when stimulated they release Norepinephrine (NE) --> increased heart rate and greater strength of contraction, increasing cardiac output and blood pressure, under normal conditions this center will dominate

gives rise to the vagus nerve (parasympathetic) which innervates the SA node, when stimulated they release acetylcholine which decreases the heart rate, cardiac output and blood pressure

widening of the internal carotid artery just above the common carotid branch, baroreceptors are located in the wall of the sinus which are stimulated when stretched

stimulate the cardioinhibitory center and inhibit the cardioacceleratory center --> decreased heart rate, cardiac output, blood pressure

baroreceptors do not stiumlate the cardioinhibitory center leaving the cardioacceleratory center free to dominate --> heart will beat faster and more forcefully to restore normal blood pressure

moniters systemic blood pressure, operates like the carotid sinus reflex

• Autonomic control: carotid reflex, aortic reflex, atrial reflex
• Chemicals: epinephrine, potassium, calcium
• Other: Temperature, emotions, gender, age

Increase

carry blood away from the heart toward the organs, have the greatest blood pressure

small vessels, which carry blood from the arteries to the capillaries, they have the greatest resistance and greatest capacity to change their diameter, they are innervated by the sympathetics

have the greatest cross sectional area, permit the exchange of nutrients and waste between blood and tissues

carry blood to the heart, one way valves prevent backflow, storage depot for blood

blood flow = change in pressure/resistance

amount of friction from viscosity (increases), vessel length (increases), vessel diameter (decreases)

cardiac output

carotid and aortic reflexes, increase in heart rate increases blood pressure (indirectly)

change the diameter of the arterioles through sympathetic innervation, decreased diameter increases resistance, directly decreasing blood pressure

located in the medulla, controls the vasomotor tone (diameter) of the arterioles

constricts those on the skin and viscera (note: parasympathetic has no effect on blood vessels)

• if too high: decrease sympathetic stimulation to arterioles (affect the vasomotor center) resulting in vasodilation and a decrease in blood pressure
• if too low: (below 80 mmHg) increase sympathetic stimualtion, resulting in vasoconstriction and increased blood pressure

detect levels of oxygen and carbon dioxide and hydrogen ions (pH), activated by hypoxia, acidity or hypercapnia (excess carbon dioxide) --> increase sympathetic (via the cardiovascular centers and vasomotor centrers) --> vasoconstriction, increased heart rate, increased force of contraction, increased blood pressure

hypoxia

collecting ducts --> renal papillae --> papillary ducts --> minor calyx --> major calyx --> renal pelvis --> ureter --> bladder --> urethra

functional unit of the kidney, Renal corpuscle (Bowman's capsule/glomerulus) --> proximal convuluted tubule --> descending limb (thin) of loop of Henle --> ascending limb (thick) of loop of Henle --> distal convuluted tubule --> collecting duct

cortical nephron (all in cortex except part of collecting duct) and juxtamedullary nephron (part in cortex, part in medulla)

control blood concentration and volume (blood pressure), regulate blood pH, remove toxic wastes from blood, formation of urine (not urea, urea is formed in the liver)

renal and vascular

renal artery --> segmental arteries --> interlobular arteries --> arcuate arteries --> interlobular arteries --> afferent arteriole --> glomerulus --> efferent arteriole --> peritubular capillaries (vasa recta) --> interlobular vein --> arcuate veins --> interlobular vein --> segmental vein --> renal vein

each efferent arteriole divides to form a network of capillaries (peritubular) around the convoluted tubules then empty into the interlobular veins

theses peritubular capillaries form long loops of thin walled vessels that dip down alongside the loop of the nephron

tubular reabsorption (renal to vascular), tubular secretion (vascular to renal) and concentration of urine

glomerular filtration, tubular reabsorption, tubular secretion

substances in the blood are filtered through the glomerular capillary membrane into Bowman's capsule then into the proximal convoluted tubule

consists of all materials in the blood except formed elements and most proteins, proteins can't pass through the basement membrane of the glomerulus

quantity of glomerular filtrate formed each minute in all nephrons (normal = 125mL/min or 180 L/day), depends on glomerular capillary pressure, colloidal osmotic pressure, Bowman's capsule pressure

60 mmHg (2 to 3 times higher than normal capullary), promotes filtration into Bowman's capsule

decrease blood flow, decrease glomerular pressure, decrease filtration rate

increase glomerular presssure, increase flitration rate

32 mmHg, protein in blood causes a sucking pressure back into the glomerular capillary network

18 mmHg, hydrostatic pressure of filtrate inside Bowman's capsule pushes fluid back into the glomerular capillary

decreased glomerular pressure (efferent arteriole dilation or afferent arteriole constriction), increased plasma colloidal pressure, increased Bowman's capsule pressure

increased glomerular pressure (efferent arteriole constriction (if not severe) and afferent arteriole dilation), decreased plasma colloidal pressure, decrease Bowman's capsule pressure

ability of the kidney to clear the plasma of various substances, glucose has the lowest plasma clearance value (slowest removal from the blood)

movement of the filtrate back into the blood of the peritubular capillaries or vasa recta (99% of the filtrate is reabsorbed), this allows the body to retain most of its nutrients

Sodium, glucose, amino acids, calcium, potassium, chloride, bicarbonate, phosphate, mostly reabsorbed in the proximal convoluted tubule

proximal tubule (66% - permeable to water), loop of henle, distal tubule (impermeable to water except in the presence of ADH), collecting duct

increased osmotic pressure, increased osmolarity, high solute concentration (concentrated solution)

decreased osmotic pressure, decreased osmolarity, low solute concentration (dilute solution)

low water concentration in the blood

vasopressin, when body is dehydrated osmotic pressure increases, osmoreceptors in hypothalamus detect this and synthesize ADH which is transported to the posterior pituitary then released into the blood, in the kidneys it increases the permeability of the distal convoluted tubule and the collecting duct to water

decreased urine volume, increase water concentration in the blood, lower blood osmotic pressure

the main mineralcorticoid released from the zona glomerulosa of the adrenal cortex, released when angiotensin II increases in the blood, potassium ion concentration increases, sodium ion concentration decreases

increases reabsorbtion of sodium at the distal convoluted tubule and the collecting duct (increases sodium ion concentration in the blood) and secrete potassium ion into the lumen of the distal convoluted tubule and the collecting duct (decrease potassium ion concentration) --> reabsorption of sodium causes the retention of water --> blood volume increases --> blood pressure increases

renin when blood pressure or volume is low --> cleaves angiotensinogen into angiotensin I, ACE in lungs converts angiotensin I to II --> angiotensin II constricts the arterioles and stimulates the zona glomerulosa to release aldosterone

permeable to water but impermeable to solutes such as NaCl, medullary interstitium has hyperosmotic compared to filtrate --> water leaves the descending limb --> filtrate becomes hyperosmotic (equalizes with interstitium)

impermeable to water but permeable to solutes, NaCl leaves the tubule, medullary interstitium becomes hypertonic which allows water to leave the descending limb

acidic is low pH and high hydrogen ion concentration, basic is high pH and low hydrogen ion concentration, balance is maintained by controlling the hydrogen ion concentration of body fluids

krebs cycle/citric acid cycle - process that produces energy and carbon dioxide which diffuses out of the cell and reacts with water to yield carbonic acid (H₂CO₃) via the enzyme carbonic anhydrase which ionizes to relaease hydrogen and bicarbonate ions

glycolysis - produces energy and lactic acid, increasing the hydrogen ion concentration

buffer systems, respiration, kidney

substance that resists change in pH when an acid or base is added, bicarbonate buffer (blood - 7.35 to 7.45), phosphate buffer (urine), protein buffer (powerful and plentiful)

• Hypoventilate --> more acidic
• Hyperventilate --> more basic
• eliminates more acid or base than all other buffers combined, adjustment takes 1 to 3 minutes

secrete hydrogen ions into the urine, reabsorb bicarbonate inons into the blood stream

adds substances to the filtrate from the blood such as potassium, hydrogen and ammonium ion

proximal and distal convoluted tubule and collecting duct, secretion of hydrogen into the urine cuases blood pH to rise, and urine pH to drop, hydrogen cannot be secreted alone, must be combined with buffers

injury to the respiratory center of the brain causing decreased rate and depth of breathing, obstruction oin air passages, pnumonia/emphysema --> amount of carbon dioxide in the body fluids is increased and pH drops (acidic)

hyperventilation from oxygen deficiency due to high altitude, severe anxiety, asprin overdoes, treat by breathing into a bag

An abnormal increase in acidic metabolic products from kidney failure (acids are not excreted) or diabetes mellitus (fats are converted to keto acids); or an abnormal loss of bicarbonate ions from prolonged diarrhea or vomiting (loss of intestinal juices)

Non-respiratory loss of acids by the body (excessive vomiting of gastric juices --> loss of HCl) or excessive intake of alkaline drugs (symptoms include nervousness, muscle spasm and convulsions)

chemical buffers, increase rate and depth of breathing, increase secretion of Hydrogen ions into the urine --> raise blood pH, lower urine pH

Chemical buffers, decrease rate and depth of breathing, decrease secretion of hydrogen ions into the urine, decrease reabsorption of bicarbonate ions --> lower blood pH, higher urine pH

located anterior to the esophagus, extends from the larynx (C6) to the carina (sternal angle, T4 disc)

mucosa is pseudostratified consisting of ciliated columnar cells, there are 16 to 20 incomplete rings (C shaped, open posteriorly)

the last tracheal cartilage, seperates the openings of the right and left main bronchi

One passes to each lung from the carina, the right is shorter, wider and more vertical and thus receives more foreign bodies, upon entering the lung hilus each main bronchi divides into secondary or lobar bronchi

3 on the right and 2 on the left

bronchioles, 10 on the right and 8 on the left, each supplies a bronchopulmonary segment of the lung, subdivide smaller and smaller until they terminate as alveolar ducts which terminate as alveolar sacs made up of alveoli (functional unit of the lung

parietal and visceral, with pleural cavity between them

attached to and lining the thoracic wall, covers the diaphragm and lateral surface of the mediastinum, can be divdied according to its location into: costal, mediastinal, diaphragmatic and cervical pleura

covers the outer surface of the lungs and extends into the interlobar fissures, becomes continuous wiht the parietal layer at the root of the lung, they hang down to form the pulmonary ligament

intrapleural pressure is lower than the intraalveolar

pressure is inversely proportional to the volume of the container --> when we breathe in we increase lung volume so that the pressure inside the lungs is less than the air pressure in the atmosphere, when we breathe out the opposite happens

muscles of inspiration: diaphragm, external intercostal muscles, accessory inspiratory muscles (forced inspiration only), sternocleidomastoid (elevates the sternum), scalenus (elevates the superior rib)

a sheet of skeletal muscle tha forms the floor of the thoracic cavity, it is dome shaped and when it contracts the dome becomes flattened increasing the vertical diameter of the throracic cavity

when contract they pull the ribs up and sternum forward --> increase the A-P diameter of the thoracic cavity

inspiration is active, expiration is normally passive

the intrapulmonic pressure, the pressure inside the lungs

the pressure between the two pleural layers (always less than the atmosphere pressure to prevent collapse of the alveolar walls

The difference between the intrapulmonic pressure and the intrapleural pressure, greatest at the end of ispiration

inspiratory muscles relax --> ribs move down, diaphragm moves up --> thoracic cavity decreases in size --> lungs recoil --> air is forced out of lungs

contract during higher levels of ventilation and when air movement out of the lungs is impeded - internal intercostal muscles (move the ribs downward) and abdominal muscles (move the inferior ribs down, compresses the abdominal viscera forcing the diaphragm upward)

collapse lung, at the end of expiration alveoli attempt to recoil inward and collapse on themselves, which would obstruct air movement

maintenance of a subatmospheric intrapleural pressure keeping the alveoli inflated and surfactant (a phospholipid produced by the type II alveolar cells or pneumocyte type II) decreases surface tension in the lungs preventing the alveoli from sticking together

the ease with which the lungs and thoracic wall can be expanded (high compliance --> lungs expand easily), it is related to elastic fibers in lung tissue, surfactant lowering the surface tension

the volume of air which moves through the respiratory passages with each normal breath, it is equal to 500mL (note: only 350mL reaches the alveoli, 150mL remains in the nose, pharynx, trachea and bronchi, this is known as dead air volume)

the extra volume of air that can be inspired beyond the normal tidal volume, usually about 3000mL

the air that can be expired forcefully beyond the normal tidal volume, usually 1100mL to 1200mL

the voume of air still remaining in the lungs after forceful expiration (about 1200mL)

the amount of air a person can breath begining at the normal expiratory level and distending the lungs to the maximum amount (tidal volume + inspiraotry reserve volume = 3500mL)

the amount of air remaining in the lungs at the end of normal expiration (expiratory reserve volume and residual volume = 2300mL)

maximum amount of air that a person can expel after first filling the lungs to the max extent then expiring to max extent (inspiratory reserve volume + tidal volume + expiratory reserve volume = 4600mL)

the max volume to which the lungs can be expandedd with the greatest possible inspiratory effect (vital capacity + residual volume = 5800mL)

20 to 25% less in women

the pressure each gas within a mixture of gases exerts

the exchange of oxygen and carbon dioxide between the alveoli and the pulmonary capillaries, results in the conversion of deoxygenated blood to oxygenated blood

105 mmHg in alveoli, 40mmHg in blood --> oxygen diffuses from the alveoli into the blood

40 mmHg in alveoli, 45 mmHg in blood --> carbon dioxide will move from blood to alveoli

exchange of oxygen and carbon dioxide between tissue blood capillaries and tissue cells, results in the conversion of oxygenated blood into deoxygenated blood

105 mmHg in blood, 40 mmHg in interstitial fluid, 23 mmHg in cells --> oxygen diffuses from blood to fluid to cells

40 mmHg in blood, 45 mmHg in fluid, 46 mmHg in cells --> carbon dioxide diffuses from cells to fluid to blood

carbon dioxide diffuses 20X faster than oxygen --> pressure difference required for carbon dioxide is much less than for oxygen

97% is carried by hemoglobin in RBCs, 3% is dissolved in plasma and cells

7% dissolved in plasma, 23% carried by hemoglobin, 70% carried as bicarbonate ion (requires carbonic anhydrase)

binding of oxygen to hemoglobin tends to displace carbon dioxide from the blood

necessary for carbon dioxide transport as bicarbonate ions

groups of neurons located in the medulla and pons dorsal respiratory center, divided into 3 areas (medullary thythmicity area, pneumotaxic area, apneustic area)

controls the basic rhythm of breathing --> inspiration = 2 seconds, expiration = 3 seconds

located in the pons, sends inhibitory impulses to the inspiratory area, limits inspiration to facilitate (increase) expiration

located in the lower pons, send stimulatory signals to the inspiratory area, inhibiting expiration, occurs only when the pneumotaxic area is inactive, otherwise the pneumotaxic area overrides

hering breurer reflex - prevents overstretch, stetch resceptors are located in the walls of the bronchi and bronchioles, when stimulated they inhibit the inspiratory area and the apneustic area via the vagus nerve --> expiration follows

area most sensitive to changes in carbon dioxide and hydrogen ions

changes in oxygen

decreased oxygen from 105 to 50 mmHg, increased carbon dioxide above 40mmHg (hypercapnia), increased hydrogen ion concentration --> stimulation of the inspiratory area, increasing respiration and correcting the imbalance

convey sensory information from receptors to the CNS

convey information from the CNS to the muscles and glands

conveys information from the CNS to sketetal muscle

conveys information from the CNS to smooth muscle, cardiac muscle and glands; sympathetic and parasympathetic

cells of the CNS that support and protect the neurons; astrocytes, oligodendrocytes, microglia, ependyma

fibrocytes - star shaped, form the blood brain barrier, support network and neurotransmitter metabolism

shorter, form the myelin sheath, analogous to schwann cells in the PNS

small cells, brain macrophages, migrate to area of injury to destroy microbes

single layer of epithelial cells, ciliated, squamous, columnar, line the ventricles, assist in circulation of CSF

dendrites (carry nerve impulses toward the cell body) and axons (carry nerve impulses away from the cell body)

a self propagating wave of electrical negativity that travels along the surface of neuron membrane, dependent on membrane potentials

the difference between the ion concentration outside and inside the plasma membrane, normal resting membrane potential is -70mV, normal muscle resting potential is -90mV

ion concentration gradients between the ICF and the ECF and the membrane permeability to specific ions, potassium is the most important

sodium and potassium, thus these two have the greatest effect on membrane potential

there are 10X as many sodium ions outside the cell as inside, concentration forces tend to move sodium ions into the cell

there are 30X as many potassium ions inside the cell as outside, concentration forces tend to move potassium ions outside the cell

maintains the concentration gradients by the active transport of 3 sodium out and 2 potassium in

potassium ion channels are open, sodium channels are closed --> potassium, with its positive charge, maintains the resting membrane potential

a nerve fiber remains polarized (charged) until stimulated by electrical, chemical, mechanical and thermal factors then it is depolarized (intensity of the stimulus exceedes the threshold of the fiber and the membrane becomes more permeable to sodium ions and that diffuse in

positive sodium ions move into the cell and the cell becomes more positive (less negative) until it reaches about -35mV

the membrane becomes more permeable to potassium ions and impermeable to sodium ions, this allows potassium ions to move out of the cell --> inside of the cell becomes more negative (less positive)

membrane potential becomes even more negative than the resting membrane potential (-95mV) after an action potential due to potassium gates remaining open

a membrane potential that temporarily reverses then returns to resting potential

time during which a second action potential cannot be initiated, even with a very strong stimulus, it lasts about 1msec and corresponds with sodium permeability changes

time during which a second action potential can be generated, but only by a stronger than normal stimulus, lasts about 10 to 15 msec and corresponds to the hyperpolarization period

action potentials occur maximally or not at all, if a stiumulus is strong enough to generate an action potential the impulse is conducted along the entire neuron

the minimal voltage required to stimulate a response

the minimum time an electrical current must flow at a voltage twice the rheobase to cause a muscle to contract

unmyelinated fibers - nerve impulses are transmitted step by step depolarization

occurs in myelinated nerve fibers, propagation of an action potential along the exposed portions of the fiber (neurofibril node or node of ranvier). the myelin sheath (created by neurolemmocytes or schwann cells) insulates the fiber and allows for faster conduction

fiber diameter (longer --> faster conduction) and degree of myelination (more myelin --> faster conduction)

A_α, A_β, A_λ, A_δ, B and C, classifies all peripheral nerve fibers

Ia, Ib, II, III, IV, classifies sensory fibers only

Ia and Ib, fastest and biggest, 72 to 120m/sec, muscle spindle primary afferent (annulospiral) (Ia), golgi tendon organ afferent (Ib) and skeletal muscle efferent

II, 36 to 72m/sec, touch pressure receptor afferent, muscle spindle secondary (flowerspray) afferent

12 to 48m/sec, muscle spindle efferent

III, 6 to 30 m/sec, pricking pain, fast pain, cold afferent

2 to 18 m/sec, preganglionic autonomic efferent

IV, slowest, smallest, <2m/sec, aching pain, slow pain, hot afferent, postganglionic autonomic efferent

the firing frequency of a receptor declines after constant stimulation

the firing frequency of a nerve fiber declines after constant stimulation

calcium channels open, calcium diffuses into the axon terminal, synaptic vesicles release neurotransmitter into the synapse, the neurotransmitters diffuse across the synapse and bind to the receptors on the post-synaptic membrane

specific ion channels are opened, at excitatory synapses there is a flow of positive ions into the cell, at inhibitory synapses there is a flow of positive ions out of the cell

The junction of an axon hillock and the axon, the first axon potential occurs here

sodium channels are opened, inside of the cell becomes more positive (depolarized) --> increases the likelihood that the postsynaptic membrane will reach threshold

potassium or chloride channels are opened --> inside of cell becomes more negative --> more difficult for the neuron to generate an impulse

if the excitatory effect is greater than the inhibitory effect, but less than the threshold level of stimulation (allows subsequent stimuli to more easily generate a nerve impulse)

the sum of all the excitatory and inhibitory effects of a single presynaptic end bulb firing 2 or more times in rapid succession

summation of the excitatory and inhibitory effects from several presynaptic end bulbs

fasiculus gracilis (legs) and fasiculus cuneatus (arms), medial leminiscus system (DRG --> nuclei --> thalamus --> sensory cortex); detect proprioception, vibration and 2pt discrimination

unconscious proprioception to the cerebellum from lower limb (DRG --> nucleus of clark C8 to L3 --> inferior cerebellar peduncle)

stretch from spindle cells of lower limbs (DRG --> nucleus of clark C8 to L3 --> inferior cerebellar peduncle)

spinocerebellar

pain and temperature (DRG --> crosses over --> thalmus --> cerebral cortex)

light touch and pressure (DRG --> crosses over --> thalmus --> cerebral cortex), sexual feelings and foreplay

tactile stimulation causing visual reflexes (DRG --> crosses over --> tectum (superior colliculus), tectum is in the midbrain

anterior and lateral corticospinal, a lesion here can casue an UMNL

voluntary motor movements from the cerebral cortex (motor cortex --> contralateral pyramid medulla --> SC anterior horn)

fine motor movements, especially of the hands (motor cortex --> ipsilateral medulla --> contralateral SC anterior horn)

facilitates flexors, inhibits extensors, coordinates movement (red nucleus in tegmentum - floor of the midbrain)

control of respiration and heartbeat, facilitates muscles, inhibits antagonists, involuntary (reticular formation - arousal and maintenance of consciousness), some fibers cross a termination

posture and balance, head and eye coordinated mov, extension of the erector spinae, involuntary (vestibular nucleus)

postural reflexes to sight and sound (tectum of the midbrain, superior colliculus) --> turns head toward sight and sound

anterior spinal roots are motor and posterior spinal roots are sensory

reflex arc is monosynaptic (2 neurons), ipsilateral, receptor is muscle spindle, response is contraction

an impulse from a single sensory neuron will stimulate contraction of one muscle (effector) and simultaneously inhibits the contraction of another muscle (antagonist)

reflex arc is polysynaptic, ipsilateral, receptor is tendon organ (type Ib), response is relaxation

to protect the muscle from damage if we try to lift something too heavy (triggered by more stretch than the stretch reflex)

annulospiral intrafusal fibers (detect dynamic stretch - rate of stretch) - innervate both bag and chain fibers

flower-spray intrafusal fibers (detect static stretch - amount of stretch) - innervate chain only

Sympathetic (lateral horns of T1 to L2) and parasympathetic (CN III, VII, IX, X and S2, S3, S4), each division has a preganglionic and a postganglionic neuron

visceral efferent neuron whose cell body is in the brain or spinal cord, it terminates at an autonomic ganglion where it synapses with a postganglionic neuron (exception is innervation to the adrenal medulla)

lies entirely outside the CNS, cell body located in an autonomic ganglion, axon is unmyelinated and it terminates in a visceral effector

All are cholinergic (acetylcholine) except most postganglionic sympathetic which is adrenergic (epinephrine and norepinephrine) (note: postganglionic sympathetic to sweat glands, erector pilae and blood vessels are cholinergic)

craniosacral division, rest and digest

occulomotor nerve --> ciliary ganglion --> intrinsic eye muscles (sphincter pupillae constricts, ciliary muscles constrict)

Facial nerve --> submandibular, pterygopalantine ganglion --> lacrimal (tears) and salivary glands (saliva)

Glossopharyngeal nerve --> otic ganglion --> parotid gland (stensons duct is opposite second molar) - saliva

Vagus nerve --> myenteric and auerbach plexus --> smooth muscle and glands of the thoracoabdominal cavity up to the left colic (splenic) flexure

Pelvic splanchnics of hypogastric plexus --> pelvic plexus --> colon below the splenic flexure (descending colon, sigmoid, rectum) and sex organs, kidney and bladder

S2,3,4 keep your penis off the floor

thoracolumbar or "fight or flight" system, T1 to L2 spinal nerves

• cell bodies in lateral horn leave through white rami communicantes and go to sympathetic chain then:
• fibers synapse in the chain and return to all spinal nerves via gray rami communicantes or
• pass through the sympathetic chain without synapsing and leave via splanchnic nerves (still preganglionic)

T5-9, celiac ganglion --> thoracoabdominal cavity through the small intestine

T10-11, superior mesenteric ganglion --> ascending colon

L1-3, inferior mesenteric ganglion --> descending colon, sigmoid, rectum, sex organs, bladder

Arteries and veins have sympathetic innervation only, capillaries have no innervation, blood vessesl have NO parasympathetic innervation

constrict blood vessels of skin and viscera, dilate blood vessels of muscles, increase heart rate, dialte lung bronchi, dilate pupils, inhibit peristalsis

no effect on blood vessels, decrease heart rate, constrict or normalize bronchi and pupils, stimulate peristalsis

postganglionic receptors are nicotinic (Ach), effectors are muscarinic (Ach) (except those that recieve NE - adrengeric)

nicotinic (also stimulated by nicotine) and muscarinic (also stimulated by muscarine - mushroom poison)

fibers which release ACh, somatic motor neurons to skeletal muscles, parasympathetic (all) and sympathetic (all pre and some post) --> ACh is excitatory

inactivates ACh by breaking it down into its components

can be excitatory or inhibitory, adrenergic fibers (release NE), most postganglionic sympathetic neurons and the adrenal medulla

alpha adrenergic and beta adrenergic

consciousness and arousal (reticular), reflex centers for heart rate, breathing and vessel diameter, equilibrium (vestibular)

pneumotoxic and apneuctic area (and w/medulla) controls breathing

eyeball, head and trunk movements

relay station for all sensory (except smell), emotions and memory, pain, temperature, light touch, pressure interpretation

mind-over-body regulation of hormones, integrates autonomic NS, rage, aggression, temperature, food intake, thirst, wakefulness, sleep

sensory interpretation, motor control, emotions, intellect, basal ganglia (gross muscle movement and muscle tone) and limbic system (emotions related to survival)

subconscious skeletal muscle for coordination, posture and balance, emotional development and modulate anger and pleasure

contains reticular activating system, concerned with arousal and wakefulness/consciousness

olfactory, sensory, exits through the cribiform plate of the ethmoid bone, function is smell (mitral cells)

Optic, sensory, exits through the optic canal, function is vision (ganglion cells)

occulomotor (parasympathetic), motor, exits through superior orbital fissure (SOF), function is pupil constriction, eye movement except LR (CN 6) and SO (CN 4)

Trochlear, motor, Superior orbital fissure, SO muscle

• V1 (opthalamic) - sensory, SOF, sensation from upper face
• V2 (maxillary) - sensory, foramen rotundum, sensation from middle face
• V3 (mandibular) - both, foramen ovale, sensation from lower face and motor to muscles of mastication

Abducens, motor, SOF, LR muscle

Facial (parasympathetic), both, sensory exits through internal auditory meatus to taste to ant. 2/3 of tongue, motor exits through the styloid foramen to muscles of fascial expression

Vestibular-cochlear, sensory, internal auditory meatus, equilibrium and hearing

Glossopharyngeal (parasympathetic), both, jugular foramen, stylopharyngeus muscle, taste to post. 1/3 of tongue

Vagus (parasympathetic to 90% of the body), both, jugular foramen, taste to epiglottis, motor to pharynx and larynx

Accessory, motor, jugular foramen, SCM and trapezius

Hypoglossal, motor, hypoglossal canal, motor to the tongue

styloglossus (retracts and elevates the tongue) and genioglossus (protrudes the tongue)

Medial (internal) closes the mouth "MMMM" and the lateral (external) opens the mouth "Lalala"

"BITE'M" Buccinator (CN 7), internal pterygoid, temporalis, external pterygoid, masseter (all CN 5) "ITEM"

light touch, pressure, low frequency vibrations

around the hair follicles

discrimination touch

continuous touch and pressure

pressure and high frequency vibrations

itch and tickle

ruffini corpuscles detect warmth, Krause corpuscles detect cold

nociceptors - free nerve endings

the awareness of the precise postition of body parts

the awareness of directions of movement

stretch receptors embedded in the skeletal muscle detecting muscle length, they consist of intrafusal fibers (3 to 10 specialized muscle fibers within the capsule) and extrafusal fibers (normal muscle fibers surrounding the capsule

located in the tendons near the junction with the muscle, they monitor muscle tension

skeletal (striated, voluntary, skeletal movement), cardiac (striated, involuntary, controlled by autonomic NS and hormones), smooth (nonstriated, involuntary, visceral, controlled by autonomic NS)

plasma membrane of the individual muscle fiber or cell

cytoplasm of a muscle cell (note: skeletal muscle is multinucleated)

membrane enclosed tubules which capture and release calcium

carry the depolarization from the end plate to the sarcoplasmic reticulum, not found in smooth muscle

thin (actin) and thick (myosin in a ratio of 2:1 in skeletal and 15:1 smooth muscle

during muscle contraction neither the thick filaments or the thin filamnets change in length, instead the thin filaments slide past the thick

corresponds to the length of the thick filament only (it's width remains constant)

corresponds to the portions of the thin filaments that do not overlap thick filaments, it's width decreases during contraction

corresponds to the center of the dark band where only thick filaments are present, it's width decreases during contraction

myoneural junction, where the synaptic end bulb and motor end plate meet

the portion of the muscle fiber that is adjacent to the synaptic end bulb of the motor neuron, it contains receptors for acetylcholine

calcium channels open, calcium diffuses into synptic end bulb causing ACh to be released into the synapse, ACh binds with a receptor on the motor end plate causing an end plate potential

the remaining ACh is destoyed by acetylcholinesterase and the end plate potential causes a muscle action potential, which passes into the muscle fiber by way of the transverse tubules, which are not found in smooth muscle, the action potential triggers the release of calcium from the sarcoplasmic reticulum, calcium binds to the troponin which initiates the muscle contraction

tropomyosin covers the myosin binding site on troponin (note: tropomyosin and troponin are part of the thin filaments - actin)

shape change (muscle contraction begins), causing tropomyosin to move which uncovers the myosin cross bridge binding sites on actin, ATP attaches to a binding site on the myosin cross bridge, giving energy to activate the cross bridge, the remaining ADP stays attached to myosin

it attaches an adjacent actin molecule, this produces a power stroke --> myosin pulls actin toward the center of the sarcomere, as the myosin cross bridge swivels it releases the ADP, another ATP attaches causing the myosin link to break and the cross bridge can attatch to another actin, one power stroke of a cross bridge results in a small movement of the thin filament

a motor neuron and the muscle fibers it stimulates (2 to 2000 muscle fibers), fine muscle control --> one neuron stimulates a few fibers, coarse muscle control --> one neuron stimulates many muscle fibers

the process of increasing the number of active motor units --> more muscle fibers involved in the contraction, the various motor neurons to a given muscle fire at different times to prevent fatigue of individual fibers

a brief contraction of all the muscle fibers in a motor unit in response to a single motor neuron action potential, it is a rapid, jerky response

a rapid succession of seperate twitches due to summation (2 seperate stimuli to the same motor unit cause a stronger contraction)

muscle length remains constant, tension changes

tesnion remains constant, muscle length changes, concentric (the muscle undergoing the strongest contraction shortens) or eccentric (the muscle that generates less tension is stretched)

type I oxidative - found in postural muscles, red due to high concentrations of myoglobin, high level of aerobic enduracne, slow ATPase, well suited for prolonged low intensity work

• Type IIa - oxidative/glycolytic - this is a red muscle fiber and is known as intermediate fast because it can sustain activity for longer periods OR it can contract with a burst of force then fatigue - used for one mile
• Type IIb - glycolytic - provides rapid force production and fatigues quickly, used in highly explosive events (100meters)

walls of hollow viscera, blood vessels, iris and ciliary muscles

non-stiated, uninucleated, no sarcomere, slow contraction, no transverse tubules, involuntary 15 actin: 1 myosin

• single unit (visceral) is the most common, connected by Gap junctions which help to facilitate nerve impulse conduction producing a wave of contraction instead of individual contractions (as occur in skeletal muscle)
• multi unit - fibers act independently, each fiber is directly innervated by an axon terminal

striated, uninucleated, with intercalated discs, involunatry, same arrangement of actin and myosin as skeletal

thickenings of the sarcolemma that connect adjacent cardiac muscle fibers, they contain gap junctions for support and spread of action potentials between cells

cardiac muscle fibers can contract without extrinsic stimulus from nerves or hormones, however, nervous and hormonal input alter the rate of discharge

cardiac fibers remain contracted longer than skeletal muscle, also cardiac muscle tissue has an extra long refractory period which allows time for the heart to relax between beats, also permits the heart to be increased significantly but prevents the heart itself from undergoing tetany

mastication (forms bolus), salivary amylase (ptyalin) digests starch to maltose

muscular tube (starts as skeletal and ends as smooth - peristalsis), stratified squamous with mucous glands, secretes mucous and transports food

lower esophageal sphincter doesn't close and HCl irritates esophagus

• zymogenic or peptic (chief) cells - secrete pepsinogen which is converted to pepsin by HCl, pepsin will aide in protein digestion
• Parietal (oxyntic) cells - secrete HCl and intrinsic factor (B12 absorption)
• Mucous cells - secrete mucus
• Enteroendocrine cells - secrete stomach gastrin which stimulates HCl and pepsinogen (zymogen) release, pepsin converts proteins to peptides

• Stimulate: vagus, cephalic reflex (thinking, smelling food), distention and hormones
• Inhibit: food in small intestine (enterogastric reflex), cholestokynin, secretin

majority of digestion and abosrption (90% - length and microvilli enhance it), crypts of lieberkuhn (intestinal juice - water and mucous), brunner's glands (mucous)

sementation (localized contraction to mix enxymes and chyme and not to push it along), peristalsis (propels chyme through the intestinal tract)

• first salivary amylase in mouth then from pancreas breaks complex carbs into disaccharides
• maltase breaks maltose into 2 glucose
• sucrase breaks sucrose into glucose and fructose
• lactase breaks lactose into glucose and galactose

pepsin (stomach), trypsin, chymotrypsin, carboxypeptidase, peptidases

bile salts and pancreatic lipase

monosaccharides, amino acids, chylomicrons, majority of water (mostly in jejunum) and electrolytes, vitamins

haustral churning (distention causes contraction and squeezes contents onward), peristalsis (slow, first part of large intestine), mass peristalsis (strong peristaltic wave from mid-transverse colon onward)

some water (cecum, ascending colon), some electrolytes and vitamins

emyptying of the stomach into the small intestine, occurs within 2 to 6 hours

distention, gastrin

excessive food in the duodenum, increased acidity of the duodenum

secreting cells --> small ducts --> pancreatic duct or accesoory duct --> common bile duct --> hepatopancreatic ampulla --> duodenum

1% (endocrine portion) - alpha (glucagon), beta (insulin), delta (somatostatin)

acini cells - makes amylase, trypsinogen, chymotrypsinogen, procarboxypeptidase

enterokinase activates trypsin, trypsin activate the rest

enzyme secretion

secretin --> sodium bicarbonate

cholecystokinin --> pancreatic enzymes

Hepatic cells (produce bile - emusify and absorb fats), Kuppfer cells (filter portal blood, phagocytic action on old WBC, RBC, bacteria, toxins), overall liver function is to store nutrients, make new materials, detoxify, metabolize and phagocytosis

glycogenesis (glucose --> glycogen), glycogenolysis (glycogen --> glucose), gluconeogenesis (AA to glucose, fructorse and galactose to glucose), glucose to fat

synthesize cholesterol, cholesterol to bile salts, increase acetyl-CoA --> ketones (ketogenesis), fatty acids --> acetyl-CoA

ammonia --> urea, synthesis of plasma proteins

antibiotics, estrogen, aldosterone, thyroxine

glucagon, vitamins (A,D,E,K,B12), minerals (iron and copper), apoferratin --> ferratin (storage)

LDH, SGPT, SGOT, arymase, alkaline phophatase

store and concentrate bile by removing water and ions, releases bile when high fat content in duodenum

mucosa (inner), submucosa, muscularis, adventia

meisners (submucosa) and myenteric (auebachs)

vagus until splenic flexure, sacral plexus (S2-4) from spenic flexure caudal

secretion of horomones into blood and maintains homeostasis. organs with endocrine function include the pancreas, ovaries, testes, kidneys, stomach, small intestine and placenta

secretion of products directly into ducts which carry the secretions to target tissue organs (ex. sweat glands, digestive, oil and mucus)

plasma membrane receptors (polypeptide hormones, neurotransmitters), activation of genes (steroid hormone, thyroid hormone)

Hormone (first messenger) --> receptor --> activates adenylate cyclase to convert ATP to cAMP --> protein kinase --> physiological response

hormone --> passes through membrane --> intracellular receptors --> specific gene interaction --> physiological response

local tissue hormones (not circulatory hormones) - potent in minute quantities, produced by mammalian cells, participate in inflammation response, dilation and constriction of blood vessels

chemical, mechanical, anaphylasix increase, asprin and acetaminophen inhibit

negative feedback (stimulus initiates action to reduce stimulus - primary control) and postive feedback (stimulus initiates action to increase stimulus)

low blood calcium --> increase PTH --> increase blood calcium --> inhibits PTH (blood sugar and insulin work the same way)

uterine contractions during labor --> increase nerve impulse --> hypothalamus --> posterior pituitary --> release oxytocin --> increase uterine distention and contractions

located in the sella turcica - adenohypophysis (anterior pituitary - glandular), neurohypophysis (posterior - nervous tissue) and pars intermedia (avascular zone between the lobes)

glandular epithelium, hormones are released and inhibited by factors produced in the hypothalamus

neuroglial cells, ADH and oxytocin are made in hypothalamus and stored here

hypo ADH

located below the larynx, consists of follicular cells (secrete thyroid hormones thyroxin/T4 and triiodothyronine/T3) and parafollicular cells (secrete calcitonin)

synthesized from iodine and tyrosine, they are released in response ot thyroid releasing factor, they regulate metabolism

Cretinism (hypo, child), myxedema (hypo, adult), graves (hyper), exopthalmic goiter, simple goiter

lowers the blood level of calcium, controlled by its own level in the blood

located on the posterior surface of the lateral lobes of the thyroid, consists of principal and oxyphil cells, secretes parathyroid hormone

increase blood calcium and decrease blood phosphate levels, stimulates osteoclasts (reabsorb bone), causes the kidney to conserve calcium and excrete phosphate

Hyperparathyroidism (excessive loss of bone) and hypoparathyroidism (drop in blood calcium and tetany)

lies behind the sternum, between the lungs, size diminishes with age, secretes several hormones related to immunity (thymosin, thymic humoral factor, thymic facotr, thymopoietin --> all promote maturation of T cells)

suprarenal (superior to the kidney), consists of an outer cortex (zona glomerulosa, zona fasciculata and zona reticularis) (all release hormones in response to ACTH from anterior pituitary) and an inner medulla

outermost layer, secretes mineralcorticoids (aldosterone - reabsorb sodium and water, excrete potassium)

Conn's disease, hypersecretion of aldosterone

middle layer of cortex, secretes glucocorticoids such as cortisol which helps to promote normal metabolism (activates gluconeogenesis, mobilizes AAs and mobilizes and catabolizes fatty acids), resist stress and anti-inflammatory

Addisons disease (hyposecretion of glucocorticoids and mineral corticoids) and cushings disease (hypersecretion of glucocorticoids)

inner layer of the cortex, secretes gonadocorticoids (estrogen and androgens - secondary sex characteristics in the adolescent, normally barely present in adult)

chromaffin cells (develop from same origin as the postganglionic cells of sympathetics) which are innervated by preganglionic sympathetic neurons

directly controlled by the autonomic NS, specifically the hypothalamus, responds rapidly to produce Epinephrine (adrenaline) or norepinephrine (noradrenalin) during stress

posterior and inferior to the stomach, it is both an endocrine and exocrine gland, endocrine portion consists of pancreatic islets or islets of langerhans (alpha - glucagon, beta - insulin, delta - somatostatin or growth hormone inhibiting factor which inhibits glucagon)

increase blood glucose levels by activating glycogenolysis and gluconeogenesis and inhibiting glycolysis and glycogenesis, secretion of glucagon is controlled by blood glucose levels

decrease blood glucose levels by activating glycolysis, glycogenesis, lipogenesis, protein synthesis and inhibiting glycogenolysis, gluconeogenesis, beta oxidation of lipids, protein breakdown, secretion of insulin is controlled by blood glucose levels

inhibit insulin and glucagon

estrogen/progesterone (female sex characteristics, menstrual cycle, pregnancy, mammary glands for lactation) and relaxin (relaxes the symphysis pubis, helps dilate the uterine cervix near the end of pregnancy, increases sperm motility)

testosterone (develop and maintain male sex characteristics) and inhibin (inhibits secretion of FSH to control sperm production)

Rathke's pouch, blood, growth hormone, prolactin, thyroid stimulating hormone, adrenocorticotrophic hormone, follicle stimulating hormone, leutinizing hormone, melanocyte stimulating hormone

neurohypophyseal bud, neural and blood, oxytocin and antidiuretic hormone

Gonadotropin-releasing hormone (GnRH)/Luteinizing hormone releasing hormone (LHRH) from hypothalamus --> follicle stimulating hormone (FSH) and luteinizing hormone (LH) in anterior pituitary --> estrogen and progesterone in ovaries

24 to 35 days (about 28), Menstrual phase (days 1-5), proliferative phase (days 6-13) and secretory phase (days 15-28) or progestational phase

discharge of blood (degeneration of the stratum functionalis layer of the endometrium caused by a sudden reduction in estrogen and progesterone), approximately 40 mm of blood are lost

under the influence of estrogen from the ovary the endometrium begins to thicken, at the time of ovulation (day 14) the endometrium is 4 mm thick, endometrial glands secrete a mucous which helps guide the sperm to the ovum

progesterone and estrogen are secreted in large quantities by the corpus luteum causing additional cellular proliferation of the endometrium to about 6 mm

follicular phase (days 1-13), ovulation (day 14), luteal phase (days 15-28)

• anterior pituitary increases secretion of FSH and LH --> accelerated growth in 6 to 12 primary follicles which release estrogen stimulating more development
• after a week or more one follicle outgrows the others and the others begin to involute (atresia), the more developed follicle secretes more estrogen
• large amounts of estrogen stimulate negative feedback on the hypothalamus to inhibit secretion of FSH and LH from the anterior pituitary (blocks further growth of the less developed follicles) --> FSH and LH decrease

About 2 days before ovulation the rate of secretion of LH rises dramatically, without this rise ovulation will not occur, FSH levels also rise but not as much, the LH causes the follicle to rupture, the follicle secretes more progesterone and less estrogen

the secretory cells of the follicle develop into the corpus luteum which secretes large quantities of estrogen and progesterone (more progesterone) and inhibin (inhibits FSH and LH secretion from anterior pituitary) --> corpus luteum will degenerate (involute) at day 26

estrogen and progesterone levels decrease, removing the negative feedback on the anterior pituitary so it can secrete large quanities of FSH and LH again, follicular growth is initiated and a new ovarian cycle begins

secreted by the placenta, will maintain the corpus luteum for the first 2 to 4 months of pregnancy