Term
| what role does the heart play |
|
Definition
| pump, pressure head for blood flow |
|
|
Term
| what is pulmonary circulation |
|
Definition
| closed group of vessels carrying blood between heart and lungs |
|
|
Term
| what is systemic circulation |
|
Definition
| closed loop between heart and other tissues |
|
|
Term
| what are the 4 one way valves |
|
Definition
| right and left atriovascular valves; right and left semilunar valves |
|
|
Term
| what is the difference between the right and left atriovascular valves |
|
Definition
| right AV valve is tricuspid while left is bicuspid (mitral) |
|
|
Term
| what does the chordae tendineae do |
|
Definition
| anchors the flaps to prevent back flow in AV valves |
|
|
Term
| what do the right and left semilunar valves do |
|
Definition
| right separates right ventricle from pulmonary artery while left separates left ventricle from aorta |
|
|
Term
| what do gap junctions do in the heart |
|
Definition
| Allow propagation of action potentials between cardiac contractile cells |
|
|
Term
| what are characteristics of cardiac myocytes |
|
Definition
| striated, mostly single nucleus, branch, have intercalated discs |
|
|
Term
| what do the desmosomes do |
|
Definition
| resist pulling forces on cardiac myocytes |
|
|
Term
| are there are any gap junctions between cells of the atria and ventricles |
|
Definition
| the only place with gap junctions is in the AV node |
|
|
Term
| what is functional syncytia |
|
Definition
| the chemical, mechanical, and electrical connection between cardiac cells |
|
|
Term
| how many of the cardiac myocytes are contractile |
|
Definition
|
|
Term
| how many of the cardiac myocytes are autorhythmic |
|
Definition
| 1% are autorhythmic (noncontractile) |
|
|
Term
| what do the autorhythmic cells do |
|
Definition
|
|
Term
| what happens in pacemaker activity |
|
Definition
| membrane potential slowly depolarizes between AP’s; Repeated cycles of depolarization and repolarization |
|
|
Term
| what happens in the initial portion of the pacemaker potential |
|
Definition
| closing of K channels; opening of I-type Na channels with VG Na channels opening at relatively neg potential; results in modest Na influx |
|
|
Term
| what happens in the latter portion of the pacemaker potential |
|
Definition
| F-type Na channels close; Transient Ca channels open (Ca influx depolarize to thresh); at thresh T-type Ca channels close, long-lasting (L) Ca VG channels open until peak potential reached; L-Ca channels close, VG K channels open, depolarization; repeat process |
|
|
Term
| what are the main parts of the cardiac conduction system |
|
Definition
| SA node, AV node, bundle of His (AV bundle), purkinje fibers |
|
|
Term
| what is the sinoatrial node (SA) |
|
Definition
| small specialized region near opening of superior vena cava |
|
|
Term
| what is the atrioventricular node (AV) |
|
Definition
| region at base of right atrium near septum and junction between atria and ventricles; Only electrical connection between atria and ventricles |
|
|
Term
| what is the bundle of his |
|
Definition
| Originates at AV node and enters interventricular septum; Left and right bundle branches and Travel down septum and curve around back toward atria along the ventricular wall |
|
|
Term
|
Definition
| small terminal fibers that extend from bundle branches and terminate throughout the myocardium |
|
|
Term
| list the conduction system from strongest pacemaker activity to weakest activty |
|
Definition
|
|
Term
| what is the path of depolarization in the heart |
|
Definition
| SA node, through internodal pathway into AV node (delayed here), through interatrial pathway into left atrium, throughout contractile myocytes of atrium, into bundle of his, through purkinje fibers, into contractile ventricular myocytes |
|
|
Term
| when does ventricular contraction occur |
|
Definition
| after atria go through excitation and contraction |
|
|
Term
| what causes ventricular filling |
|
Definition
| 80% is passive filling; 20% is a result of atrial contraction |
|
|
Term
| how do the muscle fibers excite when compared to each chamber |
|
Definition
| fibers should be excited such that each chamber has coordinated simultaneous contraction |
|
|
Term
|
Definition
| Uncoordinated excitation/constriction of cardiac myocytes |
|
|
Term
|
Definition
| application of electrical current to cause all cardiac cells to depolarize in hope that SA node resumes pacemaking |
|
|
Term
| how should atria and ventricles contract |
|
Definition
| atria should contract simultaneously and ventricles should contract simultaneously |
|
|
Term
| what are three types of abnormal pacemaker activity |
|
Definition
| latent pacemaker, complete heart block, ectopic focus |
|
|
Term
| what happens in latent pacemaker |
|
Definition
| a non-SA node autorhythmic cell takes over as pacemaker |
|
|
Term
| what happens in complete heart block |
|
Definition
| AV node is nonfunctional; no electrical connection between atria and ventricles; ventricular depolarization driven by purkinje fibers |
|
|
Term
| what happens in ectopic focus |
|
Definition
| rapid depolarization of region other than SA node; may take over and lead to inappropriate rapid contraction |
|
|
Term
| how do cardiac contractile cells |
|
Definition
| impulse originates at SA node, spreads cell to cell through gap junctions, initial depolarization to threshold, leaky K channels open, spread of current from adjacent excited cells bring Vm to threshold, at threshold VG Na channels open, at peak Na channels close and Transient K channels and close quickly, L-type Ca channels open leading to plateau phase, ordinary VG K channels open at end of plateau phase to repolarize, at rest the VG K channels close but leaky K channels open |
|
|
Term
| what is the plateau phase |
|
Definition
| a prolonged depolarization caused by Ca influx when L-type Ca channels open |
|
|
Term
| where are L-type Ca channels in cardiac myocytes |
|
Definition
|
|
Term
| where does the Ca come from |
|
Definition
| from ECF and then initiates release of more Ca from SR |
|
|
Term
| What does the increase in cytosolic Ca do |
|
Definition
| Ca binds to troponin; increases force of cardiac contraction |
|
|
Term
| what happens to Ca during cardiac relaxation |
|
Definition
| Ca is removed from cytosol; Ca ATPase pumps sequester Ca into SR; 2 active transport at PM move Ca into ECF |
|
|
Term
| Why do cardiac myocytes have long refractory periods |
|
Definition
| it is due to prolonged depolarization of the plateau phase which does not allow for twitch summation or tetanus |
|
|
Term
|
Definition
| a recording of the electrical activity of the heart that reaches the body surface |
|
|
Term
| what are the different parts of the ECG |
|
Definition
| P-wave; QRS complex; PR segment; T-wave; ST segment; TP interval |
|
|
Term
| what is associated with the P-wave in the heart |
|
Definition
| depolarization of the atrium |
|
|
Term
| what is associated with the QRS complex in the heart |
|
Definition
| depolarization of ventricles |
|
|
Term
|
Definition
| it is the combined P-wave and QRS complex with AV nodal delay |
|
|
Term
| what is associated with the T-wave in the heart |
|
Definition
| ventricular repolarization |
|
|
Term
| what is associated with the ST segment in the heart |
|
Definition
| the time when ventricles are contracting and emptying |
|
|
Term
| what is associated with the TP interval in the heart |
|
Definition
| muscle is completely at rest and ventricular filling is taking place |
|
|
Term
|
Definition
| elevated heart rate above 100bpm |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| THE CARDIAC CYCLE (GO STUDY NOW) |
|
|
Term
| when is the first heart sound heard (lub) |
|
Definition
| during ventricular excitation/ onset of ventricular systole when the AV valve closes |
|
|
Term
| when is the second heart sound heard (dub) |
|
Definition
| during ventricular repolarization; the SL valve closes |
|
|
Term
|
Definition
| volume of blood pumped by each ventricle per minute (ml/min) |
|
|
Term
| how does the CO of the left and right ventricles compare |
|
Definition
| both sides are generally equal |
|
|
Term
| what is the equation for CO |
|
Definition
|
|
Term
|
Definition
| rate of SA node depolarization |
|
|
Term
|
Definition
| intrinsic rate of SA node depolarization; parasympathetic effects; sympathetic effects |
|
|
Term
| how does the parasympathetic effect HR |
|
Definition
| Muscarinic receptors for Ach at SA node; Increased K perm at SA fibers slowing pacemaker potentials; increase in AV nodal delay |
|
|
Term
| how does the sympathetic effect HR |
|
Definition
| Release of NE from neuron (EPI from adrenal medulla) which binds to B1 receptor which causes steeper/quicker pacemaker potentials; augmentation of Na and Ca T-type channels which leads to increase of depolarizations/min and decrease in AV nodal delay |
|
|
Term
| what is stroke volume dependent on |
|
Definition
| on length-tension; increased fiber length= more forceful contractions; Frank-Starling law of heart |
|
|
Term
| what are the two types of controls in stroke volume |
|
Definition
| intrinsic controls (Frank-Starling Law); extrinsic controls (Autonomic nervous system) |
|
|
Term
| what do longer muscle fibers result in |
|
Definition
| the thick and thin filaments are closer together; more cross bridge interactions in a longer fiber |
|
|
Term
| what does the Frank-Starling law of the heart show |
|
Definition
| increasing EDV increases SV |
|
|
Term
| what are the parasympathetic effects on stroke volume |
|
Definition
| decreased contractility in atria; little to no effect on contractility in ventricles |
|
|
Term
| what are the sympathetic effects on stroke volume |
|
Definition
| increases contractile strength in atria and ventricles; increases permeability of Ca leading to increase in Ca in cytosol to be used for contraction |
|
|
Term
|
Definition
| vol of blood passing per unit of time |
|
|
Term
| what is flow directly proportional to |
|
Definition
|
|
Term
|
Definition
| it is pressure gradient directly proportional to flow difference between beginning and end |
|
|
Term
| what is Flow inversely proportional to |
|
Definition
|
|
Term
| what causes increased resistance |
|
Definition
| increased viscosity and decreased radius (radius has stronger effect), increased friction, increased surface area |
|
|
Term
| how much of an effect does radius have |
|
Definition
|
|
Term
| what is resistance proportional to |
|
Definition
|
|
Term
|
Definition
| Flow rate= (pi* delta P* r^4)/(8*viscosity*length) |
|
|
Term
| how does blood flow through arteries |
|
Definition
systole: stroke volume enters the arteries
Diastole: no blood enters arteries from the heart
Elastic Recoil |
|
|
Term
| what does elastic recoil do |
|
Definition
| provides the pressure to propel blood into arterioles |
|
|
Term
| how do pressures compare in arteries |
|
Definition
| Systolic pressure > than diastolic pressure |
|
|
Term
| how is mean arterial pressure (MAP) calculated |
|
Definition
| MAP= diastolic pressure + (Pulse Pressure/3) |
|
|
Term
|
Definition
| major resistance vessels with high degree of resistance causing drop in pressure as blood flows through; also diminishes pulsatile nature of pressure |
|
|
Term
| what does arteriolar radii adjustment do |
|
Definition
| Variable distribution of cardiac output (CO); Regulation of arterial pressure |
|
|
Term
| what is the vascular tone in arterioles |
|
Definition
| normally a tonic level of vasoconstriction |
|
|
Term
| what type of controls for vascular tone are in arterioles |
|
Definition
|
|
Term
| what intrinsic controls are used to increase CO/increase vasodialation |
|
Definition
| increase temp; increase CO2; decrease O2; Decrease pH(increase Lactic acid and carbonic acid); Increase in local [K]; Increase osmolarity; Increase in nitric oxide (powerful vasodilator) |
|
|
Term
| what is resistance proportional to |
|
Definition
|
|
Term
|
Definition
| Flow rate= (pi* delta P* r^4)/(8*viscosity*length) |
|
|
Term
| how does blood flow through arteries |
|
Definition
systole: stroke volume enters the arteries
Diastole: no blood enters arteries from the heart
Elastic Recoil |
|
|
Term
| what does elastic recoil do |
|
Definition
| provides the pressure to propel blood into arterioles |
|
|
Term
| how do pressures compare in arteries |
|
Definition
| Systolic pressure > than diastolic pressure |
|
|
Term
| how is mean arterial pressure (MAP) calculated |
|
Definition
| MAP= diastolic pressure + (Pulse Pressure/3) |
|
|
Term
|
Definition
| major resistance vessels with high degree of resistance causing drop in pressure as blood flows through; also diminishes pulsatile nature of pressure |
|
|
Term
| what does arteriolar radii adjustment do |
|
Definition
| Variable distribution of cardiac output (CO); Regulation of arterial pressure |
|
|
Term
| what is the vascular tone in arterioles |
|
Definition
| normally a tonic level of vasoconstriction |
|
|
Term
| what type of controls for vascular tone are in arterioles |
|
Definition
|
|
Term
| what intrinsic controls are used to increase CO/increase vasodialation |
|
Definition
| increase temp; increase CO2; decrease O2; Decrease pH(increase Lactic acid and carbonic acid); Increase in local [K]; Increase osmolarity; Increase in nitric oxide (powerful vasodilator) |
|
|
Term
|
Definition
| Potent vasodilator; Inhibits Ca entry into smooth muscle; Relaxation |
|
|
Term
|
Definition
| released by endothelial cells; potent vasoconstrictor |
|
|
Term
| what does Vascular endothelial growth factor (VEGF) do |
|
Definition
| Chronic hypoxia; Stimulates angiogenesis; Growth of new blood vessels |
|
|
Term
|
Definition
| Released from immune cells in response to injury; Part of the inflammation reaction; Vasodilator |
|
|
Term
| what physical factors affect stretch |
|
Definition
Heat-->vasodilation
Cold-->vasoconstriction |
|
|
Term
| what happens if MAP is increased |
|
Definition
| vessel walls stretch; smooth muscle contracts; vasoconstriction |
|
|
Term
| what does sympathetic nervous system innervate |
|
Definition
| all arteriolar smooth muscle except in brain |
|
|
Term
| what happens if NE binds to alpha receptors |
|
Definition
| vasoconstriction; Increase in resistance (R), and increase in BP |
|
|
Term
| what happens if EPI binds to B2 receptors |
|
Definition
| vasodilation in addition to metabolic conditions that favor vasodilation |
|
|
Term
| what does parasympathetic innervation cause |
|
Definition
| vasodilation in sexual tissues |
|
|
Term
|
Definition
| production of concentrated urine, “water conservation”; vasoconstrictor |
|
|
Term
| what is the role of capillaries |
|
Definition
|
|
Term
| what are characteristics of capillaries |
|
Definition
| small (7um); lots of branching; large cross-sectional area; very slow velocity of flow |
|
|
Term
| how does exchange work in capillaries |
|
Definition
| diffusion down concentration gradients; pores between cells; vesicular transport; precapillary sphincters |
|
|
Term
| what diffuses through pores in capillaries |
|
Definition
| small water soluble substances (glucose, ions, amino acids) |
|
|
Term
| how does vesicular transport work in capillaries |
|
Definition
| it regulates some specific proteins; plasma proteins stay in capillary |
|
|
Term
| how do precapillary sphincters work |
|
Definition
| Relaxed when conditions indicate an increase in cellular respiration; Contracted when indications decrease cellular respiration |
|
|
Term
|
Definition
| Pressures favor movement of fluid out of cap at the arteriolar end into cap at venule end |
|
|
Term
| what is hydrostatic pressure |
|
Definition
| the force of fluid pushing up against a wall |
|
|
Term
| what is colloid osmotic Pressure/Oncotic Pressure |
|
Definition
| pressure due to presence of nonpermeating solutes |
|
|
Term
| how is Net exchange pressure (NEP) calculated |
|
Definition
NEP=(Pc + πif)-(πp+Pif)
= (outward) - (inward) |
|
|
Term
| where does excess fluid return? How? |
|
Definition
| returned to circulatory system by lymphatic vessels |
|
|
Term
| what causes liver failure |
|
Definition
| Decrease plasma protein; Decreases πP; Cause Edema |
|
|
Term
|
Definition
| smallest of venous system; capillaries drain into venules; venules combine into veins |
|
|
Term
|
Definition
| thinner walls than arteries; blood reservoirs; adaptations to flow in low pressure conditions |
|
|
Term
| what are adaptations that veins have for flow in low pressure conditions |
|
Definition
| Wide lumen: reduces resistance; One-way valves found in veins of limbs; Muscular pump; Contraction of surrounding skeletal muscle |
|
|
Term
| what is the respiratory pump |
|
Definition
| Pressures in ventral cavity create a pump that moves blood toward heart; Inhalation: abdominal vessels are squeezed which increases pressure; Thoracic vessels have decreased pressure, which creates gradient that favors blood flow back to heart |
|
|
Term
| what happens during ventricular contraction |
|
Definition
| the AV-valves dip inward; volume of atrium expands; decrease pressure below zero to favor venous return |
|
|
Term
| what is a short-term regulation of BP |
|
Definition
|
|
Term
| characteristics of baroreceptor reflex |
|
Definition
| responds to changes in MAP and pulse pressure; mechanoreceptors; in aortic arch and carotid sinus |
|
|
Term
| what does increasing MAP cause |
|
Definition
| increase in receptor potential leading to increase in frequency of APs in afferent neuron |
|
|
Term
|
Definition
| the cardiovascular control center; the medulla (brain); decreases symp activity and increases parasymp activity |
|
|
Term
| what are ways of long-term regulation of blood pressure |
|
Definition
| control of blood volume; volume receptors and osmoreceptors regulate water and salt balance to control blood volume (increase blood volume= increase MAP) |
|
|
Term
| what does increased venous return cause |
|
Definition
| increase in SV which causes increased EDV |
|
|
