Irene Gold Physiology

anterior spinal roots are motor, posterior spinal roots are sensory

at constant temperature, a volume of gas varies inversely with pressure

at constant pressure, a volume of gas varies directly with temperature

solubility of gas in a liquid is proportional to the pressure of the gas

ventricular pressure depends on muscular tension, size and shape of the heart

cardiac output is directly proportional to diastolic filling

limits respiratory excursion via the vagus nerve

dissolved carbon dioxide in the blood (7%), combination with hemoglobin (23%), bicarbonate ion (70%)

CO2 combines with H2O by carbonic anhydrase to form carbonic acid (H2CO3) which dissociates into hydrogen and HCO₃^- which diffuses out of hte RBC into the plasma while Cl- ions diffuse in (chloride shift)

97% is carried by hemoglobin at 20mL of oxygen per 100mL of blood

• Krause - cold
• Ruffini - hot
• Meissner - light touch and pressure, fast adapting
• Pacinian - deep touch, fast adapting
• Merkel's - deep touch and pressure
• Free nerve endings - pain

normal air taken in during inspiration or breathed out during expiration (normal = 500mL)

max air that can be inspired beyond TV (normal = 3000mL)

max air that can be expired beyond TV (normal = 1100mL)

Air left in lungs after ER (normal is 1200mL)

TV + IR = 3500mL

ER + RV = 2300mL

IR + ER + TV = 4600mL

VC + RV = 5800mL

has inspiratory and expiratory control centers

apneustic center (controls expiration) and pneumotaxic center (controls inspiration) limit the duration of inspiration, but increase respiration rate

detect carbon dioxide and hydrogen and oxygen, located in medulla oblongata, carotid and aortic bodies

respiration is stimulated by an increase in PCO2, hydrogen and low PO2 and inhibited by a decrease in PCO2 or hydrogen or low PO2

occurs in diabetes mellitus, increased ketone bodies stimulate respiration (Kussmaul's breathing) causing a blowing off of CO2, thus lowering the hydrogen concentration

occurs after vomiting - the hydrogen concentration is lowered, respiration is inhibited which causes an increase in PCO2, thus increasing hydrogen concentration

respiratory alkalosis (low hydrogen ion and PCO2), rebreathing expired air (breathing into a bag) is the most effective way to reverse this

low pH of blood due to hypoventilation

posterior pituitary, connected to the base of the brain via supraoptic hypophyseal tract

store ADH/vasopressin (acts on kidneys to reabsorb water in the collecting duct, increases blood pressure) (note: decreased ADH produces polydypsia and polyuria, as in diabetes insipidus), and oxytocin (smooth muscle contractor responsible for milk let down and uterine contractions ) during labor and after birth)

Supraoptic nucleus makes ADH, Paraventricular nucleus makes oxytocin

"Rathke's pouch", influences by negative feedback or portal system releasing factors produced in the hypothalamus

FSH (follicle stimulating hormone), ACTH (adrenocorticotropin), TSH (thyrotropin/thyroid stimulating hormone), LH (leutinizing hormone/leutropin), GH (somatotropin), Prolactin - "FAT Losers Go Pout"

stimulated by growth hormone releasing factor (GHRF) from the hypothalamus, it stimulates growth of body tissues and is produced along with somatostatin (inhibiting hormone), decreases in GH produce dwarfism, increases produce giantism

stimulate the adrenal gland to release cortisol and cortisone (stress hormones), keeps up blood sugar, depresses WBC count

stimulate the thyroid to release T3 and T4, keeps up BMR (basal metabolic rate)

stimulate follicles in preparation for ovulation in females, stimulates sperm production in males

responsible for ovulation and growth of follicle after fertilization in females, regulates testosterone production in males

stimulates milk production post partum

melanocyte stimulating hormone

calcitonin, thyroxine (T4), triiodothyronine (T3)

takes calcium out of the blood and puts it into the bone, made by the parafollicular cells of the thyroid, stimulated by high blood calcium levels

major hormone from the thyroid, regulates metabolism

more active than thyroxine, important basal metabolism

cretinism in children, myxedema in adult

increased metabolic processes, increased sympathetics and graves disease

increase blood calcium (takes it out of the bone), decrease reabsorption of phosphates, stimulated by low blood calcium

take calcium out of the bone and into the blood, important in many enzye reactions and for contraction of muscle, secreted by parathyroid

decreases produce tetany or muscle twitches, increases are seen in osteitis fibrosa cystica (cystic fibrosus)

• Zona glomerulosa - produces aldosterone (regulates salt)
• Zona fasciculatat - produces cortisol (regulates sugar)
• Zona reticularis - produce androgen (regulates sex)

A mineralocorticoid that reduces sodium excretion by the kidneys and increases potassium excretion, stimulated by high potassium levels

a glucocorticoids that controls metabolism of carbohydrates, fats and proteins

medulla is derived from neural crest cells, secretes epinephrine (adrenalin) and norepinephrine (noradrenalin), acts as postganglionic sympathetic nervous system, raise blood sugar from liver

made in the hypothalamus to inhibit growth hormone. Also, made by the delta cells of the pancreas to inhibit insulin and glucagon in the pancreas, gastrin in the gastric mucosa, secretin in the intestinal mucosa and renin in the kidneys

a peptide formed in the liver and other tissues which mediates the effects of growth hormone on cartilage

estrogen and progesterone

produced by the ovarian follicle after stimulation by FSH. Thickens the endometrial lining of the uterus in the proliferative phase of the menstrual cycle (1st stage)

produced by the corpus luteum after ovulation. Increases thicknesss of the uterine lining to make it ready for implantation. Increase in 2nd stage of the menstrual cycle called secretory stage. Also responsible for increase in body temperature (called thermogenic hormone).

produced by interstitial cells of Leydig in testes, produces male sex characteristics

insulin and glucagon

secreted by the beta cells in response to glucose. takes sugar out of the bloodstream and into the body tissues

responsible for increasing blood sugar

auerbach's plexus, in muscular layer of digestive tract for GI motility

in the submucosa, promotes secretion

salivary amylase (ptyalinogen --> ptylin) breaks down starch

• chief cells secrete pepsinogen in the presence of HCl becomes pepsin and renin clots milk
• parietal cells produce HCl (activates pepsinogen) and intrinsic factor (allows B12 absorption)
• mucosa cells secrete gastrin which helps with protein digestion (stimulates stomach emptying and pancreas)

• cholecystokinin - contraction of the gall bladder when fat is present (slows down food emptying, CCK is stronger than gastrin)
• secretin - stimulates the flow of pancreatic juice (amylase and lipase) and decreases gastic motility (buffers acid chyme from stomach)
• enterogastrone - closes pyloric sphincter in response to fats (lipids)
• enterokinase - converts trypsinogen to trypsin

lipase, amylase, maltase, trypsinogen (activated by enterokinase in intestine), trypsin and chymotrypsin split proteins

pacemaker, self excitatory to the internodal pathways to the AV node (delays impulse) then to the AV bundle (of His) to the purkinje system which conducts the impulse to the ventricles

• P wave - atrial depolarization
• QRS wave - ventricular depolarization (atrial repolarization is covered up by this)
• T wave - ventricular repolarization
• U wave (if present) - repolarization of papillary muscle

• primary - elongation of PR interval
• secondary - winkbock's phenomena (elongation of PR until two atrial depolarizations (P waves) appear before a QRS)
• Complete - no QRS wave (bundle of his)

diastole is the period of relaxation, systole produces contraction

first heart sound is from closure of AV valves during isometric contraction, 2nd heart sound is from closure of the aortic and pulmonic valves during isometric relaxation at the beginning of diastole

the small downward deflection in the arterial pulse or pressure contour immediately following the closure of the semilunar valves sometimes used as a marker for the end of systole or ejection period (ST segment)

cardiac output is directly proportional to diastolic filling

in the carotid and aortic arches, responds to changes in blood pressure

Aortic regurgitation, pulmonic regurgitation, mitral stenosis, tricuspid stenosis (note: the opposite happens in systole)

calcium is stored in the sarcoplasmic reticulum. The calcium in the sarcoplasm is low, the ATP is attached to the myosin crossbridges (this prevents the combining of actin and myosin)

calcium is released at the myoneural junction which causes acetylcholine release to the T tubules --> sarcoplasmic reticulum releases calcium

myosin, which breaks the ATP to ADP and phosphate, calcium binds with troponin which is attached to tropomyosin (covers binding site until calcium attaches) --> actin is left free --> actin and myosin combine --> contraction

cholinesterase destroys acetylcholine, calcium goes back to the sarcoplasmic reticulum and the myosin becomes inactivated, ADP is converted back to ATP, ATP combines with myosin, tropomyosin-troponin complex reattaches to actin and bridges separate to reform --> relaxation

• Inside the cells is K⁺ and Mg²⁺
• Outside the cell is Na⁺ and Cl^-
• stimulation increases membrane permeability to sodium

decreased membrane permeability to K⁺ and Cl^- or Na⁺ goes into the cell by diffusion (channels open)

K⁺ goes out of the cell (channels open) or Cl^- goes into the cell (channels open) or decreased membrane permeability to Na⁺

potassium moving out of the cell returns membrane back to resting potential (channels open)

-90 mV for muscle or -70 mV for neuron

When a second action potential cannot be elicited (repolarization is still taking place)

When a second action potential can be elicited but must be a greater stimulus than the first (cell is hyperpolarized)

minimum current strength for an action potential to occur

time needed using two times the rheobase for excitation

ACH, norepinephrine, glutamate, dopamine, serotonin

glycine, GABA (gamma amino butyric acid)

ACH

ACH and Norepinephrine, Acetylcholine activates two receptors - muscarine (effector cells of parasympathetic - stomach) and nicotinic (skeletal muscle fibers, sympathetic and parasympatheitic)

• fight or flight
• vasoconstriction of b1 vessels of skin
• vasodilation of b1 vessels of muscle
• increases heart rate and force of contraction
• dilates bronchi, increases depth of breath
• decreases GI secretions
• decreases peristalsis
• dilates pupils

• wine and dine
• decrease heart rate and force of contraction
• constrict bronchi, shallow breaths
• increase GI secretions
• Increase peristalsis
• constricts pupils

• sympathetic - lateral horn of T1 to L2
• parasympathetic - CN 3, 7, 9, 10 and S2-4

adrenal medulla, erector pili muscles (hair), sweat glands, smooth muscles of arterioles that supply peripheral blood vessels for vasoconstriction to increase blood pressure

• Alpha - quiet, awake, disappears in sleep
• Beta - specific mental activity, brain tension, REM
• Delta - deep sleep, infancy, brain disorders, non-REM sleep
• Theta - disappointment, frustration, normal in children, stress in adults, seen in second and third stage of sleep (non-REM)

from renal artery to interlobar to arcuate to interlobular to afferent arteriole to glomerulus to efferent arteriole to peritubular capillaries

filters the blood, no active transport, no protein passes through, glucose goes through

reabsorption and secretion from the glomerular filtrate into the peritubular capillaries, acts by diffusion or active transport

maximum glucose reabsorption, 65% of water is reabsorbed, most Na⁺ and Cl^- is absorbed, all amino acids are reabsorbed

osmotic pressure moves water into the interstitial tissue thus concentrating the urine

NaCl can pass through the tubule into the tissues, but water cannot penetrate here

NaCl and water are reabsorbed, K⁺ and H⁺ are secreted, aldosterone has the most influence here

hormone control of water, reabsorption of filtrate, ADH makes collecting ducts more or less permeable to water

colloid osmotic pressure and hydrostatic pressure promote reabsorption

collecting ducts to pyramids, minor calyces, major calyces, renal sinus, renal pelvis, ureter, bladder, urethra

erythropoietin release (goes to bone marrow to increase RBC production). Erythropoietin peaks 24 hours after but don't see RBCs for 2 to 3 days

A decrease in blood pressure or volume will stimulate the JG cells to produce Renin which is released into the blood

liver produces angiotensinogen and releases it into the blood where it is cleaved by renin to angiotensin I, ACE (in lungs - angiotensin converting enzyme) converts angiotensin I to angiotensin II

stimulates thirst, constricts blood vessels (efferent arterioles), stimulates ADH, stimulates adrenal cortex to secrete aldosterone from the zona glomerulosa (reabsorbs sodium and water, excretes potassium from distal tubule)

filter, regulate blood pressure, produce hormones

200 times that of oxygen

pH, oxygen concentration, temp. or DPG (diphosphate glycerate) affects the binding affinity of oxygen for hemoglobin

• decreased H⁺ (increased pH)
• decreased CO₂ (increased oxygen)
• decreased temp.
• decreased DPG

myosin only, no actin, disappears with contraction

all of myosin, remains the same with contraction

Actin only, shortens with contraction

from one z-disc to another z-disc (in the middle of I-band)

has a plateu due to calcium channels, elongates the absolute refractory period preventing tetany of the heart

no troponin or T-tubules