Flashcards based on Irene Gold board review for physiology
What is the Bell Magende law?
anterior spinal roots are motor, posterior spinal roots are sensory
What is Boyle's law?
at constant temperature, a volume of gas varies inversely with pressure
What is Charles law?
at constant pressure, a volume of gas varies directly with temperature
What is Henry's law?
solubility of gas in a liquid is proportional to the pressure of the gas
What is LaPlace law?
ventricular pressure depends on muscular tension, size and shape of the heart
What is starling's law?
cardiac output is directly proportional to diastolic filling
What is Hering Breuer's law?
limits respiratory excursion via the vagus nerve
What are the three forms carbon dioxide is transported in?
dissolved carbon dioxide in the blood (7%), combination with hemoglobin (23%), bicarbonate ion (70%)
How is bicarbonate ion formed?
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)
How is oxygen transported?
97% is carried by hemoglobin at 20mL of oxygen per 100mL of blood
What are the types of nerve endings and what do they detect?
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
What is tidal volume (TV)?
normal air taken in during inspiration or breathed out during expiration (normal = 500mL)
What is inspiratory reserve (IR)?
max air that can be inspired beyond TV (normal = 3000mL)
What is expiratory reserve (ER)?
max air that can be expired beyond TV (normal = 1100mL)
What is the residual volume (RV)?
Air left in lungs after ER (normal is 1200mL)
What is the inspiratory capacity?
TV + IR = 3500mL
What is the functional residual capacity?
ER + RV = 2300mL
What is the vital capacity?
IR + ER + TV = 4600mL
What is the total lung capacity?
VC + RV = 5800mL
What role does the medulla play in respiration?
has inspiratory and expiratory control centers
What role does the pons play in respiration?
apneustic center (controls expiration) and pneumotaxic center (controls inspiration) limit the duration of inspiration, but increase respiration rate
Where are chemoreceptors and what do they detect?
detect carbon dioxide and hydrogen and oxygen, located in medulla oblongata, carotid and aortic bodies
What will stimulate respiration? What will inhibit respiration?
respiration is stimulated by an increase in PCO2, hydrogen and low PO2 and inhibited by a decrease in PCO2 or hydrogen or low PO2
What is metabolic acidosis?
occurs in diabetes mellitus, increased ketone bodies stimulate respiration (Kussmaul's breathing) causing a blowing off of CO2, thus lowering the hydrogen concentration
What is metabolic alkalosis?
occurs after vomiting - the hydrogen concentration is lowered, respiration is inhibited which causes an increase in PCO2, thus increasing hydrogen concentration
What does hyperventilation cause?
respiratory alkalosis (low hydrogen ion and PCO2), rebreathing expired air (breathing into a bag) is the most effective way to reverse this
What is respiratory acidosis?
low pH of blood due to hypoventilation
What is the neurohypophysis? How is it connected to the brain?
posterior pituitary, connected to the base of the brain via supraoptic hypophyseal tract
What does the posterior pituitary do?
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)
What makes ADH and oxytocin?
Supraoptic nucleus makes ADH, Paraventricular nucleus makes oxytocin
Where does the anterior pituitary (adenohypophysis/glandularophysis) come from? What is it influenced by?
"Rathke's pouch", influences by negative feedback or portal system releasing factors produced in the hypothalamus
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
What does ACTH do?
stimulate the adrenal gland to release cortisol and cortisone (stress hormones), keeps up blood sugar, depresses WBC count
What does TSH do?
stimulate the thyroid to release T3 and T4, keeps up BMR (basal metabolic rate)
What does FSH do?
stimulate follicles in preparation for ovulation in females, stimulates sperm production in males
What does LH do?
responsible for ovulation and growth of follicle after fertilization in females, regulates testosterone production in males
What does prolactin do?
stimulates milk production post partum
What does the pars intermedia secrete?
melanocyte stimulating hormone
What does the thyroid secrete?
calcitonin, thyroxine (T4), triiodothyronine (T3)
What does calcitonin do?
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
What is thyroxine?
major hormone from the thyroid, regulates metabolism
What is triiodothyronine?
more active than thyroxine, important basal metabolism
What will decreased thyroid hormone produce?
cretinism in children, myxedema in adult
What will increased thyroid hormone produce?
increased metabolic processes, increased sympathetics and graves disease
What does parathyroid hormone do?
increase blood calcium (takes it out of the bone), decrease reabsorption of phosphates, stimulated by low blood calcium
What does parathormone do?
take calcium out of the bone and into the blood, important in many enzye reactions and for contraction of muscle, secreted by parathyroid
How will changes in parathrormone affect the body?
decreases produce tetany or muscle twitches, increases are seen in osteitis fibrosa cystica (cystic fibrosus)
What are the three zones of the adrenal cortex and what does each produce?
Zona glomerulosa - produces aldosterone (regulates salt)
Zona fasciculatat - produces cortisol (regulates sugar)
Zona reticularis - produce androgen (regulates sex)
What does aldosterone do?
A mineralocorticoid that reduces sodium excretion by the kidneys and increases potassium excretion, stimulated by high potassium levels
What does cortisol do?
a glucocorticoids that controls metabolism of carbohydrates, fats and proteins
What is the adrenal medulla? What does it secrete?
medulla is derived from neural crest cells, secretes epinephrine (adrenalin) and norepinephrine (noradrenalin), acts as postganglionic sympathetic nervous system, raise blood sugar from liver
What is somatostatin?
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
What is somatomedin?
a peptide formed in the liver and other tissues which mediates the effects of growth hormone on cartilage
What do the ovaries produce?
estrogen and progesterone
What is estrogen?
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)
What is progesterone?
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).
What is testosterone?
produced by interstitial cells of Leydig in testes, produces male sex characteristics
What does the pancreas secrete?
insulin and glucagon
What is insulin?
secreted by the beta cells in response to glucose. takes sugar out of the bloodstream and into the body tissues
What is glucagon?
responsible for increasing blood sugar
What is the myenteric plexus?
auerbach's plexus, in muscular layer of digestive tract for GI motility
What is the Meissner's plexus?
in the submucosa, promotes secretion
What digestion occurs in the mouth?
salivary amylase (ptyalinogen --> ptylin) breaks down starch
What digestion occurs in the stomach?
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)
What digestion occurs in the duodenum?
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
What does the pancreas produce?
lipase, amylase, maltase, trypsinogen (activated by enterokinase in intestine), trypsin and chymotrypsin split proteins
What is the SA node?
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
What are the waves of the ECG?
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
What are the types of heart blocks?
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)
What is diastole? systole?
diastole is the period of relaxation, systole produces contraction
What are the 1st and 2nd heart sounds?
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
What is the dicrotic notch?
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)
What is starling's law?
cardiac output is directly proportional to diastolic filling
What are baroreceptors?
in the carotid and aortic arches, responds to changes in blood pressure
What types of regurgitation and stenosis occur in diastole?
Aortic regurgitation, pulmonic regurgitation, mitral stenosis, tricuspid stenosis (note: the opposite happens in systole)
What occurs in a relaxed muscle?
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)
What occurs when a nerve impulse fires to a muscle?
calcium is released at the myoneural junction which causes acetylcholine release to the T tubules --> sarcoplasmic reticulum releases calcium
What does the calcium activate?
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
What occurs after the 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
What ions are more prevalent inside the cell? Outside? What does stimulation do?
Inside the cells is K+ and Mg2+
Outside the cell is Na+ and Cl-
stimulation increases membrane permeability to sodium
What occurs in passive depolarization?
decreased membrane permeability to K+ and Cl- or Na+ goes into the cell by diffusion (channels open)
What causes hyperpolarization?
K+ goes out of the cell (channels open) or Cl- goes into the cell (channels open) or decreased membrane permeability to Na+
What causes repolarization of the cell?
potassium moving out of the cell returns membrane back to resting potential (channels open)
What is the normal resting membrane potential?
-90 mV for muscle or -70 mV for neuron
What is the absolute refractory period?
When a second action potential cannot be elicited (repolarization is still taking place)
What is the relative refractory period?
When a second action potential can be elicited but must be a greater stimulus than the first (cell is hyperpolarized)
What is rheobase?
minimum current strength for an action potential to occur
What is chronaxie?
time needed using two times the rheobase for excitation
What neurotransmitter is used at the neuromuscular (NM) junction?
What neurotransmitter is used in the autonomic NS?
ACH and Norepinephrine, Acetylcholine activates two receptors - muscarine (effector cells of parasympathetic - stomach) and nicotinic (skeletal muscle fibers, sympathetic and parasympatheitic)
What effects does the sympathetic nervous system have on the body?
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
What effects does the parasympathetic nervous system have on the body?
wine and dine
decrease heart rate and force of contraction
constrict bronchi, shallow breaths
increase GI secretions
Where do sympathetic and parasympathetic originate?
sympathetic - lateral horn of T1 to L2
parasympathetic - CN 3, 7, 9, 10 and S2-4
What body parts only recieve stimulation from the sympathetic?
adrenal medulla, erector pili muscles (hair), sweat glands, smooth muscles of arterioles that supply peripheral blood vessels for vasoconstriction to increase blood pressure
What are the types of brain waves?
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)
How does blood get to and from the glomerulus of the kidney?
from renal artery to interlobar to arcuate to interlobular to afferent arteriole to glomerulus to efferent arteriole to peritubular capillaries
What does the glomerulus do?
filters the blood, no active transport, no protein passes through, glucose goes through
What occurs in the tubules?
reabsorption and secretion from the glomerular filtrate into the peritubular capillaries, acts by diffusion or active transport
What occurs in the proximal tubule?
maximum glucose reabsorption, 65% of water is reabsorbed, most Na+ and Cl- is absorbed, all amino acids are reabsorbed
What occurs in the descending limb of the loop of Henle?
osmotic pressure moves water into the interstitial tissue thus concentrating the urine
What occurs in the ascending limb of the loop of Henle?
NaCl can pass through the tubule into the tissues, but water cannot penetrate here
What occurs in the distal tubule of the kidney
NaCl and water are reabsorbed, K+ and H+ are secreted, aldosterone has the most influence here
What occurs in collecting duct?
hormone control of water, reabsorption of filtrate, ADH makes collecting ducts more or less permeable to water
What occurs in the peritubular capillaries?
colloid osmotic pressure and hydrostatic pressure promote reabsorption
Where does urine flow?
collecting ducts to pyramids, minor calyces, major calyces, renal sinus, renal pelvis, ureter, bladder, urethra
What will kidney hypoxia stimulate?
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
What stimulates the Juxtaglomerular cells? What do they produce?
A decrease in blood pressure or volume will stimulate the JG cells to produce Renin which is released into the blood
Where is angiotensinogen produced? What happens to it after?
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
What does angiotensin II do?
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)
What are functions of kidney?
filter, regulate blood pressure, produce hormones
What is the binding affinity for CO to hemoglobin?
200 times that of oxygen
What is the bohr effect?
pH, oxygen concentration, temp. or DPG (diphosphate glycerate) affects the binding affinity of oxygen for hemoglobin
What will increase oxygen's affinity for hemoglobin?
decreased H+ (increased pH)
decreased CO2 (increased oxygen)
What is the H-band?
myosin only, no actin, disappears with contraction
What is the A-band?
all of myosin, remains the same with contraction
What is the I-band?
Actin only, shortens with contraction
What is a sarcomere?
from one z-disc to another z-disc (in the middle of I-band)
What is unique about cardiac muscle?
has a plateu due to calcium channels, elongates the absolute refractory period preventing tetany of the heart