Heart and circulatory system Flashcards

Question

sympathetic

Answer 1

nerves from thoracic region of spinal cord project to heart as cardiac nerves - innervate SA and AV nodes, coronary vessels and atrial and ventricular myocardium - inc HR and force of contraction, greater contraction for same end diastolic volume (inc stroke volume) also, epinephrine and norepinephrine (catecholamines) from adrenal medulla (endocrine gland that sits atop kidneys) in total affect: 1. channels that bring calcuim into cell 2. channels that allow calcium to leave sarcoplasmic reticulum 3. calcium troponin interaction (heart contracts faster) 4. reuptake of calcium into sarc ret (heart relaxes faster)

Answer 2

amine derived from amino acid tyrosine, act as hormones or neurotransmitters - bind to 2 diff classes of receptors; a and b adrenergic receptors - neurons that secrete them are adrenergic neurons - norepinephrine secreting neurons are noradrenergic

Answer 3

from postganglionic sympathetic neurons (CNS-> preganglionic fiber -> ganglion: cluster of nerves -> post ganglionic fiber -> organ - inc rate and degree of cardiac muscle depolarization, inc in frequency in AP and force and velocity of contraction how? is agonist (binds to) for cell surface B andregergic receptors, which cause G-protein mediated syn and accumulation of cAMP in cardiac cells, opens Ca2+ slow channels, inc cells ability to depolarize, helps open Na+ channels

Answer 4

hormone released from adrenal medulla - derived from norepinephrine, similar in structure/has same effect on heart nerve signals to adrenal gland activate conversion of stores of norepinephrine to epinephrine and cause release - inc cardiac output and BGLs

Answer 5

(in some crustaceans) beat under control of nervous system (all other animals) - contractions initiated within heart - nerves control rate

Answer 6

branched, connected to one another via intercalated discs (at Z line of sarcomere) that have gap junctions

Answer 7

heart stimulates itself to contract at regular intervals intervals - pacemaker (excitable) cells in SA node generate APs have specialized cell membrane that allows Na+, K+, and Ca+ to cross and trigger their electrical impulses

Answer 8

cardiomyocytes (heart muscle cells) contract via depolarization and repolarization of cell membranes via movement of ions. 1. wave of excitation spreads from SA node through atria -> AV node (slower transmission here, everything else rapidly) -> bundle of His -> bundle branches -> Purkinje fibers -> ventricular heart muscle cells -> causes vent contraction

Answer 9

rise up to threshold: 1. permeability to K+ is declining (less K leaving) 2. funny channels open at low membrane potential let Na+ in 3. transient Ca2+ channels open bring Ca in (fast open and close for the rest of it) (T-type channel, initiate) peak: everything else lowers, long lasting Calcium channels open (L-type channel, sustain) repolarization: 1. calcium channels close 2. inc permeability to K+ (leaves out) 3. funny channels pick up a little at very end so symp effect: inc permeability to Na and Ca, dec to K para: opposite

Answer 10

mixed sodium potassium current dual activation by voltage and cAMP

Answer 11

no electrical connection between muscle cells of atria and ventricles (just connective tissue) - want slow transmission because want time for things to fill, don’t want atria and ventricles to pump at same time AP in cardiac muscle longer than AP in skeletal muscle long refractory period (tetanus not possible) no self re-excitation, rate set by pacemaker

Answer 12

AP spreads from plasma membrane to T tubules (lumen of T tubules is continuous with extracellular fluid) skeletal muscle: opens Ca channels in Sarc Ret cardiac: AP opens voltage gated Ca channels in T tubule membrane, diffuses through channels from extracellular fluid into cell binds to Ca receptors in sarc ret, opens channels, results in large net diffuse of Ca from sarc ret into cytosol, binds troponin, etc -> contraction

Answer 13

P wave: depolarization from SA node 0.08 to 0.10 sec flat region between P and QRS: impulse traveling within AV node and bundle of His, atria repolariszing but masked by QRS wave PR interval (onset of P to beginning of QRS) represents time between onset of atrial depolarization and onset of ventricular depolarization QRS: depolarization of ventricles (fast) S-T: vent are completely depolarized (corresponds to plateau phase of vent APs) T wave: vent repolarize

Answer 14

arterioles (small branches of arteries) deliver blood to capillaries constrict and dilate to regulate flow and pressure of blood into capillaries

Answer 15

capillaries: exchange material with interstitial fluid site of exchange thinnest walls (single endothelial layer) no smooth muscle, large surface area variation in contraction of smooth muscles of arterioles and precapillary sphincters (band of smooth muscle that adjusts the blood flow into each capillary) controls blood flow through capillaries slower blood flow than arteries and veins to maximize exchange two mechanisms drive exchange of substances 1. diffusion along concentration gradients 2. bulk flow structure: 2 endothelial cells make up wall intercellular cleft and fused vesicle channels allow water soluble substances to diffuse O2 and CO2 diffuse across membrane (hydrophobic) pressure of blood (hydrostatic pressure) higher than pressure of interstitial fluid at arteriole end of capillary bed -> causes solutes + water to be forced out of capillaries by hydrostatic pressure at venous end, net force is pulling fluid back into blood tissue fluid circulates (dynamic equilibrium) so that tissues receive solutes from cap pores

Answer 16

carry blood away from heart walls: 1. inner endothelial layer 2. middle smooth muscle layer 3. outer layer of elastic fibers (elastin, in connective tissue) thick walled - withstand high pressure, large diameter, low resistance to flow, stretched when blood flows out from heart even when heart relaxes, walls rebound and give blood extra push so that artery return to normal size and keep blood flowing (this is why pressure doesn’t drop to 0)

Answer 17

collect blood from capillaries

Answer 18

return blood to heart act as blood reservoirs and conduits one-way valves prevent blood from flowing backward blood moves through veins in response to 1. contraction of smooth muscle in walls of veins 2. contraction of skeletal muscle surrounding veins

Answer 19

whether fluid will move out of or into capillary, depends on 1. net filtration pressure: hydrostatic pressure of blood in the capillaries minus hydrostatic pressure of tissue fluid outside the capillaries 2. oncotic pressure

Answer 20

concentrations of solutes are generally same in tissue (interstitial fluid) and plasma - protein conc of plasma is greater than int fluid colloid osmotic pressure is greater in the plasma than in the interstitial fluid equation fluid out-fluid in (hydrostatic pressure in capillary+colloid osmotic pressure of interstitial fluid (should be 0))-(hydrostatic pressure of interstitial fluid-colloid osmotic pressure of blood plasma)

Answer 21

osmotic pressure exerted by plasma proteins (albumin)

Answer 22

difference between colloid osmotic pressure in the plasma and interstitial fluid

Answer 23

not all fluid from tissues can be reabsorbed into plasma collects excess interstitial fluid (becomes lymph), transports it to lymph ducts that empty into veins key component of immune system extensive network of vessels - made of lymph nodes, spleen, thymus, tonsils remove viruses, bacteria, damaged cells and cellular debris from lymph and bloodstream, defend body against infection and cancer

Answer 24

impacted by 1. cardiac output 2. degree of constriction of blood vessels 3. total blood volume autonomic nervous system and endocrine system interact to coordinate mechanisms using nitric oxide: major inducer of vasodilation endothelin: peptide and major inducer of vasoconstriction

Answer 25

local control: meets needs of particular tissue ex. active hyperemia: response to increase in metabolism of tissue O2 used faster, metabolites inc, arterioles dilating to achieve enough blood flow flow autoregulation: response to drop in blood pressure vessel wall not as stretched, smooth muscle around arteriole contracting less strongly, dilates, flow restored extrinsic/central controls: needs of whole body (sympathetic nerves and plasma epinephrine on arterioles in skeletal muscles) ex. fight or flight epinephrine released, dilate vessels, more blood flow to vessels in skeletal muscle

Answer 26

1. respiratory medium 2. respiratory surface - thin - large surface area -moist (in order to dissolve in water to move in and out of epithelial cells) - human lungs invaginated to keep from drying out - moisture is added to air in mouth/nasal passages

Answer 27

flow of respiratory medium over external side of respiratory surface

Answer 28

flow of blood/other body fluids on the internal side of respiratory surface

Answer 29

simple diffusion of molecules drives exchange of gases across resp surface (higher to lower regions of conc) area of resp surface set total quantity of gases exchanged by diffusion

Answer 30

allow air to become saturated with water before reaches resp surface - helps reduce water loss by evaporation - inc surface area for gas exchange

Answer 31

positive pressure (frog) - air forced into lungs by muscle contractions negative pressure (mammals) - muscle contractions expand lungs, lowering air pressure inside - air pulled into lungs - air exhaled passively due to relaxation of diaphragm and external intercostal muscles, elastic recoil of lungs (pleural membranes) - can forcefully exhale as well

Answer 32

1. airways filter moisten and warm entering air a. nose and mouth -> pharynx, larynx, trachea (non muscular tubes, rings of cartilage) -> two bronchi leading to lungs (have cilia (moves mat up throat) and mucus (trap debri/bacteria) secreting cells)-> bronchioles (contain smooth muscle cells can control diameter) -> alveoli surrounded by networks of blood capillaries 2. contractions of diaphragm and muscles between ribs ventilated lungs (lowers pressure of air in lungs and causes air to be pulled inwards) 3. volume of inhaled/exhaled air varies 4. centers that control breathing located in brain stem (pons and medulla like cardio) 5. use negative pressure breathing

Answer 33

double layer of epithelial tissue that covers lungs inner layer (visceral): attached to lung surface outer layer (parietal): attached to surface of chest cavity fluid filled space in between allows lungs to move without abrasion elastic, recoil: stretching of lungs stores energy that can be released when expelling air

Answer 34

amt of air moved in and out of lungs during inhalation and exhalation ( at rest around 500ml)

Answer 35

total volume person can inhale and exhale breathing as deeply as possible (max male: 4800ml, female: 3400)

Answer 36

air remaining in lungs after as much air as possible is exhaled (males: 1200ml females: 1000ml)

Answer 37

in response to differences in pressure PV=nRT R=nRT/V - at constant T, pressure of a gas is inversely proportional to its volume

Answer 38

need a change in size of thorax (chest cavity) 1. negative pressure interpleural space keeps lungs in contact with chest wall 2. surface tension of pleural fluid also leads to close apposition of the lung surfaces with the chest wall 3. lungs are compliant (stretchy) and elastic (recoil) inhalation: diaphragm contracts/moves down, rib cage expands, inc volume, dec pressure, draws air into lung exhalation: diaphragm relaxes, moves up, rib cage gets smaller, dec in volume, inc in pressure, expel air

Answer 39

Ptp: transpulmonary pressure: diff in pressure between inside and outside of lungs (Palv-Pip) equal and opposite to elastic recoil pressure of the lung Pip: pressure in pleural space Patm: pressure in nose, mouth, airways under physiological conditions : Ptp always positive, Pip always negative, Palv moves from slightly positive to slightly negative

Answer 40

breathe in: chest wall expands (inc in volume), lowers Pip Ptp becomes more pos as result and lungs expand now as lungs expand and increase volume, Palm becomes less than Patm and air rushes in

Answer 41

respiratory muscles relaxed, no air flow Palv-Patm=0 (equal to e/o) lungs always hace air in them, positive Ptp negative Pip “hold” lungs open and chest wall in

Answer 42

at mid cycle (peak of breath in), net air flow is 0 bc chest wall is no longer expanding but hasn’t begun to contract, lung size not changing, epiglottis open to atmosphere Pip has gone from -4 to -7 due to the expansion of the chest wall (inc in volume) at end of inspiration

Answer 43

resp muscles relax, chest wall and lungs get smaller due to elastic recoil Palv inc, to above Patm Pip returns to -4 value

Answer 44

measure of ease of expansion of lungs 2 determinants 1. stretchability of lunges (red by scar tissue) 2. surface tension: attractive forces between water molecules in the film of fluid that line alveoli

Answer 45

surfactant: mixture of lipoprotein molecules in alveolar cells (type II pneumocytes) - forms monolayer over surface of alveolar fluid/water molecules within alveoli that reduce the surface tension - reduces cohesive forces between water m;olecules on alveolar surface, inc stretchability, prevent lungs from collapsing and forming smaller volume, fluid filled alveoli

Answer 46

control mechanisms 1. regulation centers in brain stem 2. local chemical controls goal is to optimize gas exchange match rate of air and blood flow in lungs link rate and depth of breathing to body’s needs

Answer 47

diaphragm and intercostal muscles are skeletal muscles controlled by motor nerves whose destruction results in death inspiration initiated by burst of APs in spinal motor nerves to inspiratory muscles, APs cease, ins muscles relax, expiration occurs as elastic lungs recoil quiet breathing = little to no muscle contraction/relaxation involved in expiration (passive)

Answer 48

basic rhythm: prod by neurons in medulla called medullary resp center 2 groups of neurons DRG dorsal resp group: primaraly fire during inspiration, stimulates diaphragm. have input to spinal motor neurons (phrenic (innervate diaphragm) and intercostal nerves) VRG: adds to rate and depth of breathing by stimulating forceful exhalation and inhalation (excercise) upper part of VRG (pacemaker cells + pre-botzinger complex) believed to compromise respiratory rhythm generator

Answer 49

medulla detects changes in levels of CO2 in blood and body fluids by receiving signals from peripheral chemoreceptors 1. carotid bodies 2. aortic bodies central chemoreceptors (detect changes in CO2): located in medulla that send signals (excitatory synaptic input( to medullary neurons) control centers in medulla and pons adjust rate and depth of breathing

Answer 50

peripheral: respond to changes in arterial blood 1. dec Po2 (hypoxia) 2. inc H+ (metabolic acidosis) 3. inc PCO2 (resp acidosis) central: respond to changes in brain extracellular fluid 1. inc in Pco2 via associated changes in H+ (can’t pick up H+ changes directly bc can’t cross blood brain barrier)

Answer 51

if air flow< capillary blood flow, O2 lvls in blood fall smooth muscles in walls of lung arterioles contract, red blood flow, more time for blood to pick up O2

Answer 52

- air flow is. way through bronchi and trachea. mixes fresh and used air bc we don’t expel all the air from the lungs each time we breathe - air coming in includes some used air that was in dead space, not all air gets to the lungs

Answer 53

one hemoglobin molecule can combine with 4 O2 combines inside erythrocytes in heme group O2 combined with hemoglobin maintain large partial pressure gradient between O2 in alveolar air and in blood binding of O2 to Hb enhanced by cooperativity in tissues: less PO2 in tissues than blood plus affinity of Hb for O2 is decreased by - inc in CO2 (binds to hemoglobin and protons at a amino group and knocks O2 off) - drop in pH (may come from inc CO2 or lactic acid - inc in temp (factors prod by active tissues) it takes a drop of Partial pressure of O2 in arterial blood from 100 mmHg to 60 to hace saturation of hemoglobin start to drop

Answer 54

CO2 produced by cellular oxidation in active tissues, diffuses from cells to interstitial fluid to blood plasma partial pressure of CO2 is higher in tissues than in blood - 10% dissolves in plasma - 70% converted to H+ and HCO-3 (bicarbonate) ions - H+ combines with hemoglobin or proteins - 20% combines with hemoglobin in lungs: partial pressure of CO2 higher in blood than in alveolar air - CO2 released from blood into alveolar air - rxns reversed to pack CO2 into blood

Answer 55

osmolarity in milliosmoles per liter mOsm/L water moves osmotically from solution of lower osmolarity to higher osmolarity (from where there is more free water to where there is less) hyposmotic = more water comparatively = hypotonic

Answer 56

min pressure needed to be applied to a solution to prevent the inward flow of water across a semipermeable membrane

Answer 57

osmoregulators and osmoconformers excretion is part of this extracellular fluids filtered through tubules formed from transport epithelium (layer of cells with transport proteins in their membrane) and released as urine

Answer 58

glucose, amino acids, ions na k cl water, HCO3- in kidney this occurs in proximal convoluted tubule secreted: H+ and K+ maintaining ion and pH balance in kidney, occurs mostly in distal convoluted tubule

Answer 59

getting rid of nitrogenous wastes 1. ammonia (aquatic animals), dilute 2. urea: ammonia with HCO3-, req less water (bc urine is hyper osmotic to body fluids) 3. uric acid: conserves more water

Answer 60

use is to conserve nutrients and water, balance salts, concentrate wastes for excretion - nephrons have permeability differences (established by transport proteins in regions) - diff concentration gradients of molecules and ions in interstitial fluid in kidney - network of capillaries surrounding nephrons reabsorb ions, water, etc.

Answer 61

leaves individual nephrons -> processed further in collecting ducts -> pools in renal pelvis -> flows through ureter to urinary bladder -> urethra to exterior

Answer 62

flows through renal artery -> interlobular artery -> afferent arteriole and enters glomerulus (cluster of blood vessels) in bowman’s capsule -> split into 50 capillaries that have very thin walls - solutes filtered due to pressure gradient between blood and fluid in bowman’s capsule (controlled by contraction/dilation of arterioles) after afferent arteriole, blood enters vasa recta (blood vessels near loop of henle exits through renal vein

Answer 63

specialized tubule >1 million nephrons juxtamedullary 20% long loops extend to medulla cortical 80%: short loops mostly located in cortex

Answer 64

blood vessels around loop of henle in medulla region (peritubular capillaries located more cortically) - imp in maintaining ion gradient of medulla to facilitate osmosis with loop of henle

Answer 65

1. filtration (ultrafiltration) bowman’s capsule (pressure driven) - diameter of afferent arteriole and glomerular capillaries are relatively large - efferent arterioles: receive blood from glomerulus has smaller diameter -> blood “backs up “ in glomerulus, keeping pressure high - 47.5 gal of fluid each day - high pressure forced small moleculares through the filter into glomerular capsule cans the basement membrane of Bowman’s capsule and into nephron - fluid formed this way is called glomerular filtrate 2. reabsorption - proximal tubule secretes H+ into filtrate, reabsorbs Na Cl K and HCO water and nutrients, - Na+/H+ exchangers and Na+/K+ pumps in epithelium of tubule move Na from filtrate to interstitial fluid, results in voltage gradient which causes Cl ions to follow 3. secretion (N+ and NH3)

Answer 66

reabsorpbtion of water ions and nutrients back into interstitial fluid main function proximal tubule secretes H+ into filtrate, reabsorbs Na Cl K and HCO water and nutrients Na+/H+ exchangers and Na+/K+ pumps in epithelium of tubule move Na from filtrate to interstitial fluid, results in voltage gradient which causes Cl ions to follow - specific membrane proteins actively transport other things like glucose amino acids from filtrate in tubule to int fluid, filtrate now hypoismotic to interstitial fluid, water moves from tubule to int fluid via aquaporins - all will move from int fluid to peritubular capillaries and return to the circulation

Answer 67

sets up gradient of solutes in interstitial fluid - very high solute concentration towards pelvis of kidney - descending segment has aquaporins for water reabsorption (can’t absorb salt though) (move out of tubule as it passes increasingly higher regions of solute concentrations of interstitial fluid in medulla) by bottom of tubule osmolarity of fluid in tubule = osmolarity of medulla fluid - ascending is Na+ and Cl reabsorption active transport, fluid in tubule has lower osmolarity as ascends towards cortex, no aquaporins - allows production of urine that is hyperosmotic to blood

Answer 68

design of loop of henle and vasa recta - enables interstitial fluid in kidney cortex and medulla to maintain a concentration gradient - helps keep blood coming from vasa recta to not be too hyperosmotic, allows water reabsorption, and production of conc urine filtrate flow through LoH is opposite from vasa recta ascending LOH releases Na which makes cell more solute vasa recta capillaries have fenestrae (pores) that make them highly permeable to water and solutes, allowing for equilibrium. blood in vasa recta remains nearly isosmotic to interstitial fluid at each level so it doesn’t undo the osmotic gradient in the interstitial fluid

Answer 69

highly soluble in water, practically non-toxic cont to total osmolarity of interstitial fluid diffuse into descending vasa recta. same solutes then diffuse out of ascending vasa recta then back into interstitial fluid

Answer 70

Na+, Cl HO and HCO3- are reabsorbed K+ secreted and H+

Answer 71

- concentrates urine - increasing solute gradient in the medulla - some urea passively trans out of duct, adds to solute gradient in medulla - H+ secreted into duct

Answer 72

enzyme, a protease, also called angiotensinogenase

Answer 73

water reabsorption in kidney can be regulated by ADH - released from pituitary when osmoreceptors in hypothalamus detect an inc in osmolarity of body fluid - angiotensin (peptide hormone) also stimulates secretion of ADH. inc water reabsorption, stimulates thirst

Answer 74

- too little water in blood detected by hypothalamus - more ADH produced by pituitary gland - more water reabsorbed by kidneys, caused by ADH - blood becomes less concentrated negative feedback: hypothalamus detects change in blood concentration. pituitary produces less ADH, blood returns to correct osmotic concentration

Answer 75

1. baroreceptors in aorta and carotids detect stretch and send signals to medulla oblongata in brainstem - dec BP by activating parasympathetic nervous system and inhibitbition of sym 2. intra renal baroreceptors = juxtaglomerular cells -> renin (an enzyme) (leads to an inc in BP) - Atria -> ANP (atrial netriuretic factor) protein hormone inhibits effects of renin and leads to BP dec ANP promotes natriuresis (loss of sodium) - atrial myocytes synthesize, store and release ANP in response to stretch - cause renal vasodilation -> inc blood flow = inc glomerular filtration rate (GFR), more filtrate is processed, more urine (with Na+ and water is released Na+ -> total fluid volume -> BP

Answer 76

autoregulation system: involves interactions between glomerulus and nephron filtration rate kept constant juxtaglomerular apparatus: located in region where distal convoluted tubule contracts the afferent arteriole (which carries blood to glomerulus) end result: signals from JG cells act to constrict or dilate afferent arterioles which keep blood flow and filtration constant

Answer 77

when blood volume and blood pressure drop, raise bP renin (enzyme released from JGA) triggers angiotensin production by converting it to I which is converted to II (by ACE) 1. stimulates arteriole constriction 2. stimulates ADH (inc water reabsorption) 3. stimulants aldosterone (hormone from adrenal gland) - inc Na + reabsorption ANF inhibits fxs of renin renin is protease (kidneys) angiotensin hormone (liver) aldosterone is hormone (adrenal cortex)

Answer 78

site of BP reg via RAAS in kidney located side of glomerulus formed by conjunction of cells of 1. macula densa (distal tubule) 2. juxtaglomerular cells of afferent arteriole 3. extra glomerular mesangial cells

Answer 79

cells that monitor Na+ concentration in the filtrate and regulate via paracrine signals the release of renin by the adjacent JG cells - low Na+ = macula densa cells signal JG cells to make renin JG cells are specialized smooth muscle cells in the wall of the afferent arteriole which synthesize and secrete renin - have beta adrenergic receptors (can induce secretion when stimulated by epinephrine)

Answer 80

actions of ANP opposite to renin inhibits reabsorption of Na+ directly (on nephron) inhibits release of aldosterone ANP: causes dilation of afferent arteriole that leads to the kidney nephron while constricting the efferent arteriole inc rate of blood flow into glomerulus dec flow out of glomerulus via efferent arteriole this increases GFR, inc prod urine, dec reabsorption of Na+ and water

Answer 81

Na/H+ pumps in proximal tubule transport Na+ from filtrate into próx tubules and transport H+ from proximal tubule cells into filtrate -> combines with HCO3- to form H2CO3 carbonic acid. enzyme carbonic a hydrate CA located at apical cell membrane of prox tubule cell converts HCO3 to H2O and CO2 in distal, H+ secreted into filtrate using H+ ATPase pumps (located on apical side) Na/K ATPase pumps located at basolateral membrane of tubule cells help maintain conc gradient which facilitates difff of NA+ into distal tubule cell

Answer 82

less H+ present in filtrate to react with HCO30 in filtrate result: less HCO3- reabsorbed, more in urine

Answer 83

proximal tubule cells can make extra bicarbonate from metabolism of glutamine HCO3 is formed and released into the blood while ammonia (NH3) and ammonium ion (NH*) are produced and enter the filtrate. The extra bicarbonate serves as a buffer in the blood. The ammonia (NHs) and the phosphates, HPO, - (which have been secreted into the filtrate) react with excess H+, allowing the H+ to be eliminated in the urine in a buffered state as NH* and N2PO4

Answer 84

EPO is hormone produced primery by kidneys plays role in prod of RBCs

Answer 85

renin angiotensinogen angiotensin I angiotensin II

Heart and circulatory system Flashcards

(109 cards)