Physiology 2 (pt 3)

• Amount of blood pumped out by each ventricle in 1 minute
• Usually 5.0 liters (total blood volume)
• May reach as high as 35 L/min during exercise of a well-trained athlete

CO= HR x SV

Stroke volume is typically 0.07 L/beat (amt of blood pumped out of the ventricles each heartbeat)

Governs the most important extrinsic controls on the heart exerted by the ANS

• The most important extrinic controls on heart rate
• Breaks and accelerator of the heart
• Sympathetic nervous system increases HR as well as increase force of contraction which increases stroke volume

• Activated by emotional or physical stress and release norepi and epi to bind to the B₁ andrenergenic receptors of the heart
• Threshold is reached quicker and results in an increased heart rate and increased force of contraction

Initiated by cardiac responses which are mediated by the release of acetylcholine which hyper polarizes the membranes by opening potassium channels

• Reduces HR
• Activated in certain emotional conditions such as grief and severe depression
• Inhibitor of SA node so its always on
• Binds to muscarinic receptors of in the heart
• Keeps the HR at 70bpm

The SA note would increase to its inherent rate of 100 bpm

Much of the sensory input is generated by baroreceptors (pressure) that responds to changes in systemic blood pressure; pressure receptors

• The emotional centers of the brain will "turn on" certain divisions of the ANS in response to specific emotional conditions
• Depressive: stimulates parasympathetic on HR
• Excitement: stimulate sympathetic to increase HR

• Heat increases the HR by enhancing the metabolic rate of cardiac cells
• Cold does the opposite

Plasma electrolyte imbalances pose real dangers to the heart

• Decreased levels depress the heart-- hypocalcemia
• Increased levels, hypercalcemia, tightly couples the excitation/contraction mechanism and prolongs the AP which increase spastic contractions

• Increased, hypernatremia, inhibits transport of calcium into the cardiac cells
• Blocking heart contraction

• Increased hyperkalemia interferes with the depolarization mechanism; may lead to heart block and cardiac arrest
• Injecting K is a way to stop the heart

• Thyroid gland hormone causes a slower but more sustained increase in the HR
• Enhances the effect of epi and norepi and increases metabolic rate and oxygen consumption
• More in the winter because its cold and we need to increase HR and the body temp

• The pressure against the walls of arteries and arterioles
• Fluids driven in a closed system will operate under pressure
• Highest closest to the heart (arteries)
• Slower in capillaries but minimal in the veins; larger lumen to reduce friction

BP= Cardiac ouput x resistance

• Cardiac output: amt of blood pumped out by each ventricle in 1 minute-- usually 5.5 liters (total blood volume)
• Resistance: amt of friction blood encounters

• Aorta: 120 mmHg
• Arterioles: 60
• Capillaries: 20
• Veins: 20
• Superior vena cava and right atrium: 0

• Maximum arterial pressure reached during peak ventricular ejection
• Pressure against the artery walls during ejection
• Avg about 120

• Minimum arterial pressure occurs just before ventricular ejection begins
• Avg 70-80
• Pressure during relaxation

• Difference between systolic pressure and diastolic pressure
• PP= SP-DP
• Can be felt as a pulsation or throb in the arteries in wrist or neck with each heart beat
• Used for measuring pathology

• Stiffness in the aorta, the largest artery
• May be due to high blood pressure or fatty deposits damaging the walls of the arteries, leaving them less elastic (atherosclerosis)

• Arterial pressure is continuously changing throughout the cardiac cycle
• Avg pressure is not the halfway value between diastolic and systolic bc diastole lasts long

DP + 1/3(SP-DP) or DP + 1/3pulse pressure

• High in the neck in the carotid sinus
• Aortic arch
• These imputs integrates at medullary cardiovascular center

• Send signals to the hypothalamus and MCC
• Response of the Sympathetic and parasympathetic nervous system is to adjust cardiac output and resistance to make it return to normal

Hypothalamus will increase CO and Resistance

Hypothalamus will decrease CO and resistance

This increases BP so hypothalamus will decrease resistance to bring BP back down

Resistance decreases, so BP decreases therefore hypothalamus will increase CO in order to bring BP back up

• If change is on the left, then the right is the opposite
• If change is on the right, the BP would be the same as the change and the last variable is the opposite

As volume increases, so does BP bc there is now more resistance from fluid pressing

BP increases resistance goes up

• Coorelated w/strength of heart contractions
• If this increases, then BP increases

• More blood, more venous return, more resistance, more BP
• Usually only 20 mmHg and depends on several factors to return its volume to heart
• Venodilation would lower systemic BP bc cardiac output and resistance would decrease

• When you strain for bowel movement, creates pressure which lowers venous return
• This goes down which lowers cardiac level to a dangerous level
• May cause you to pass out if you have a heart condition

• Increasing contractility of the heart, possibly by ANS stimulation, increases CO
• Therefore, would increase BP

• Innervates smooth muscle in vessel walls
• Produces generalized vasoconstriction to our core and a rise in BP and increase in resistance

• Not a dramatic rise bc it also causes vasodilation to peripheral muscles to allow to run away
• Sedentary exercise would see rise in BP

• Releases acetylcholine which causes systemic vasodilation
• Especially to arterioles supplying skin and digestive
• Causes BP to decrease

Increases CO, promotes vasoconstriction which causes increase in BP

• Causes increase in HR and enhances effects of epi and norepi
• Causes raise in BP

• Increase BP when fluid volume and BP fall to dangerous low levels (severe hemmorhage); also causes vasoconstriction
• Both increase BP so if you have low BP then you may see an increase in this (ADH)

• Causes intense vasoconstriction promoting rapid rise in systemic bp if your BP should drop
• Stimulates aldosterone which increases blood volume by reabsorbing sodium and water
• Increase BP

• Internal resistance to flow and is related to the thickness of a fluid
• More viscous increases resistance and increase BP

• Longer the vessel, the greater the resistance
• Lots of work for the heart if you gain weight bc extra resistance for BP

• One of the most potent vasoconstrictors
• Released in response to low blood flow and enhances calcium entry into vascular smooth muscle
• Increases BP

• Released by endothelial cells in response to high blood flow rate called hyperemia
• Signals acetylcholine and bradykinin to promote vasodilation
• Decrease BP in hyperemia situation

• Chemical that is synthesized by the platelets in response to vessel damage
• Causes vasoconstriction and increased bp

• Chemical produced to promote vasodilation
• Decrease in BP

Causes blood volume and bp to decline

• Temporary low BP and dizziness when suddenly rising
• Chronic: hint of poor nutrition and warning sign for addison's disease
• Acute: sign of circulatory shock

• May be transient or persistent; silent killer
• Primary or essential hypertension: risk factors include diet, obesity
• Secondary: due to identifiable disorders
• Causes problems over time: transient ischemic attacks and long term can cause kidneys to fail from pressure

• ADH or Vasopressin
• Released from Posterior Pituitary Gland
• Cause kidneys to remove water from urine
• Stimulates water reabsorption in nephron
• Vasoconstriction; increase BP

• OT
• Released from Posterior Pituitary Gland
• Stimulates contraction during childbirth
• Stimulates the release of milk; not production

• GH
• Released from Anterior Pituitary Gland
• Stimulates skeletal muscle and bone growth and maintenance by activating somatomedin or insulin-like growth factor
• Depends on epithelial plate- if line then bone widens
• Peaks at adolescence

• TSH
• Released from Anterior Pituitary Gland
• Stimulates the production and secretion of TH from thyroid gland 
• Controlled by hypothalamus
• TRH -> TSH -> TH

• ACTH
• Released from Anterior Pituitary Gland
• Stimulates production and release of adrenal cortex hormones i.e cortisol
• Release controlled by hypothalamus
• CRH -> ACTH -> cortisol

• FSH
• Released from Anterior Pituitary Gland
• Stimulates growth of follicle and maturation of egg each month
• Stimulates production and secretion of estrogen
• Stimulates the seminiferous tubules to produce sperm
• Release is controlled by hypothalamus

• LH
• Released from Anterior Pituitary Gland
• Induces Ovulation
• Stimulates ruptured follicle to become corpus luteum
• Secrete only source of progesterone and works with FSH to stimulate secretion of estrogen
• Stimulates testes to develop and secrete large amts of testosterone
• Regulated by the hypothalamus

• PRL 
• Released from Anterior Pituitary Gland
• Initiates and maintains milk production
• Only small amounts secreted due to PIF (prolactin inhibiting factor)
• No known function in males

• Released in Pineal Gland
• Produced in response to light/dark cycles
• May inhibit secretions of FSH and LH (regulating period)
• Biological clock
• Attributed to mood

• TH
• Released from thyroid gland
• Produced in response to TSH or cold
• Iodine is crucial to the production
• Influences metabolism, growth and development (works with GH)
• Increases basal metabolic activity of cells (BMR)
• Aging may decrease its release

• When a baby is born with low levels of thyroxine, TH
• Have a distinct cry and can be cured by TH replacement

• Released from thyroid gland
• Homeostasis of blood calcium levels
• Lowers amt of calcium accelerating update by bones
• Bone Sparing Chemical

• PTH
• Released by the parathyroid gland
• Greatest role by raising blood calcium
• Helps activate vitamin D and increase Ca absorption in GI tract
• Promotes bone breakdown by osteoclasts to release calcium
• Promotes reabsorption of calcium from urine in kidneys

• Released by adrenal cortex
• Acts on cells in kidney to increase reabsorption of sodium ions from urine and return to blood
• Stimulates excretion of K ions
• Can cause high blood pressure bc higher Na causes more retention of water i.e. more volume
• Dehydration and sodium deficiency can trigger secretion

• Released by adrenal cortex
• Produced in response to stress and ACTH
• Enables body to withstand short term stressful situations, increasing blood glucose, suppress immune response 
• Decrease pain sensitivity and seratonin
• Increases memory and attention
• Works w/others to promote normal metabolism
• Remove inflammation to allow wounds to heal

• Adrenaline
• Released by adrenal medulla
• Produced in response to stress and sympathetic nervous system stimulation
• Bind to alpha and beta receptors for fight or flight
• Increase HR, dilate pupil, increase blood sugar, increase vasodilation
• Inhibits GI mobility

• Released by the pancreas
• Produced by beta cells of inslets of langerhans in response to increase in blood sugar
• Lowers blood glucose by stimulating glucose metabolism
• Promotes protein synthesis and slows glucose formation

• Produced by alpha cells of the inslets of langerhans in the pancreases in response to decrease in blood glucose
• Raises it by stimulating glycogenolysis, gluconeogensis, and inhibiting insulin
• Stimulates the release of glucose from the liver

• Produced primarily by the follicle in the ovary, but also corpus luteum, adrenal cortex and some fat cells
• Stimulates maturation of female reproductive tract
• Stimulate fat deposits in boobs, hips, butt
• Primary sex hormone during proliferative phase of menstrual cycle
• Important for readying the uterus

• Produced primarily by the corpus luteum in the ovary
• Stimulates formation of lactiferous glands in breasts, increase vascular supply to endometrium and stimulates endometrial gland secretions
• Regulated by LH and primary sex hormone during secretory phase of menstrual cycle
• Promotes uterine conditions for embryo
• Levels fail if not pregnant and menstruation continues

• Primarily by the interstitial cells of testes and adrenal cortex
• Testosterone is the primary androgen
• Needed for formation of male reproductive tract
• Stimulate male secondary sexual characteristics