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Cardio Ex 1: Cardio Anatomy and Physiology Review
Terms in this set (169)
The IVC and SVC passively empties into the ____ atrium. (and the coronary sinus...controlled by thebesian valve)
T/F: During diastole, the right atrium mooostly PASSIVELY lets venous blood into the right ventricle.
True: Diastole causes relaxation of the ventricular wall
- additional volume of blood in ventricles causes by atrial systole
-accounts for 5-30% of cardiac output
When the right ventricle contracts, venous blood is pushed where?
Into the pulmonary valve to the pulmonary artery
What contraction provides the pressure that sustains pulmonary blood flow for ventilation and diffusion?
Ventricular contraction (sistole)
T/F: Deoxygenated blood is in the left atrium.
False: the blood is from the pulmonary vein so it is oxygenated
What portion of the heart is the "workhorse" because it sustains systemic blood pressure?
What are the two walls of the pericardium?
Fibrous and serious pericardium
which ventricle is strongest?
which ventricle moves more blood?
- left vent
- theyre equal! trick q
What are the two layers of the pericardium?
fibrous pericardium (outer outer)
serous pericardium: 2 layers: Parietal and visceral (epicardium/inner) layers
Describe the pericardial cavity
Between the visceral and parietal layers, it is a potential space
Name some issues that can occur with the pericardial cavity.
What is the purpose of pericardial fluid?
Two types of cardiac muscle fibers
Excitatory and contractile fibers
What is the purpose of excitatory fibers?
Conduct electrical current through the tissue of heart, stimulating contractile fibers
The walls of the atria and ventricles are made of ------ ------ muscle.
What is the arrangement of cardiac muscle?
Cell membranes of cardiac muscles are fused with each other at -------- ------ and function as ------- gap junctions between cells.
describe the phases of myocardium contraction
Cardiac muscle is a ------ of many heart cells that causes the action potential to spread rapidly through them.
When the action potential passes over the cardiac cell membrane, the T Tubules are -------.
When the cells are depolarized, what enters the cells to open voltage-gated channels on the Sarcoplasmic Reticulum?
Calcium, facilitating the contractile action of troponin
Removal of calcium makes the muscle ------.
What is the beginning of one heartbeat to the beginning of the next beat called?
What manages heart beats?
When heart rate increases, duration of each cardiac cycle -----.
Cardiac relaxation = -------.
What fills with blood?
Ventricles, due to the pressure of the atrium passively pushing blood into ventricles
cardiac contraction is called
Which is stronger: diastole or systole?
Systole (left ventricle force is strongest in heart)
Cardiac/ventricular contraction = ------.
What fills with blood?
Systole; Ventricles contract so pulmonary artery and aorta fill with blood.
At the end of systole, the heart relaxes and the cardiac cycle ------ -----.
what happens if the electrical conduction was thrown off...how would this affect the cardiac cycel
examples: Atrial fibrilation and ventrical fibrilation or complete heart block (no electrical communication)
AV valves are located ------- posteriorly to the pulmonary and aortic valves.
Describe the structure of the pulmonary and aortic valves.
Made of sturdy cusps (leaflets). (lock together w pressure)
Which valves are held down by "ropes"?
AV valves (keep the "tent" from flopping around)
Why are the heart valves important?
Prevent backflow during systole/contraction
Which valves are closed during diastole?
Pulmonary and aortic valves
Which valves are closed during systole?
AV valves - tricuspid and bicuspid
What are the muscles that hold the AV valves (mitral and tricuspid) valves closed due to pressure w/in the ventricles?
Chordae Tendineae and Papillary Muscles (kind of pull but mostly hold closed)
What is the purpose of the papillary muscles?
To provide more strength to stop flaps from bulging into atria
things like mitral valve prolapse can happen
What makes the heart sounds heard during auscultation?
Closing of the valves
Abnormal heart sounds generally occur when something is ------ wrong.
What is the LUB sound?
What is the cause?
First heart sound, S1;
Closure of AV valves at beginning of systole
What is the DUB sound?
What is the cause?
Second heart sound, S1;
Closure of aortic and pulmonary valves at the beginning of diastole.
between S1 and S2 is _____
The heart receives its oxygenated blood supply from the ----- -----.
when does blood enter the coronary arteries
during diastole- at rest
Where is the right coronary artery located?
Within the right cusp of the aortic valve (left is in the left valve CAN YOU BELIEVE IT!!)
Branches of the right coronary artery
Right marginal artery
Branches of the left coronary artery
Left Anterior Descending(widow maker)
80% of ppl are right or left dominant? aka that artery is what supplies the posterior interventricular artery0
What is the single largest killer of men and women in the US?
Coronary Artery Atherosclerosis
Where is Atherosclerosis most commonly found?
Cerebellum, coronary arteries, and aorta
What are Atheromas?
Where do they occur?
Most commonly in the curved areas of the heart's arteries
The more developed the plaque = higher degree of arterial blockage
What conditions predispose the arterial wall to have LDL cholesterol enter the tunica intima?
HTN, diabetes, and age.... which cause microinflammation and damage to the atrial walls
What is the earliest pathologic lesion of atherosclerosis?
How are "Foam Cells" formed in the arteries?
Serum lipoproteins in the tunica intima triggers monocytes to phagocytize LDL cholesterol
Atherosclerosis, what is the body doing?
Trying to heal the injury caused by LDL and debris by forming an extracellular CT matrix over it.
Atherosclerosis: Some fibrous caps over the phagocytized LDL in arteries can rupture, causing thrombus formation, which might do what?
Block the vessels! Plaque rupture is the main event that causes acute presentation of coronary syndromes.
What causes the acute presentation of coronary syndromes?
Plaque rupture (of Atherosclerosis)
By impairing or obstructing normal BF, atherosclerotic buildup causes what?
Myocardial ischemia or infarction.
Why have CAD (Coronary Artery Disease) mortalities decreased?
Better cardiac procedures, CABG procedures, thrombolytic therapy, PCI (cath lab), and lifestyle modifications
Atrial contraction (kick) occurs about ---- of a second before what?
strong ventricular contraction
can the excitatory conduction system be damaged
yes susceptible--- esp by CAD
What is the purpose of the Sinoatrial Node?
Generate normal rhythmical impulses for entire heart system
As atrial walls are depolarized, the impulse is transferred down Internodal Pathways to the ------- node at the inferior atrium.
even if the internodal pathways arent there.....the SA node would still eventually...slower..but reach and stimulate the AV node
How big is the Sinoatrial Node?
Action potentials generated at the -------- spread immediately throughout the bilateral atrial muscle walls.
cells of the SA node are ___ negative at rest than the hyperpolarized muscle cells throughout the heart
What type of channels slowly leak sodium and calcium into the cell of the SA node?
What is the purpose?
Self-excitation by pushing the threshold to discharge
this is why self excitation can occur aka sa node can keep heart beating
How many seconds after the SA node fires does the depolarization reach the AV node?
at what node does the electrical impulse slow down..why?
there are less gap junctions but hella cells the impulse has to travel through
Impulse takes ----- seconds to move through the AV Node and then ----- seconds to move through the AV fibrous tissue via penetrating fibers of the AV bundle. (Total delay of -----)
What is the total AV Node delay?
What would cause a slower AV node impulse?
Decreased numbers of gap junctions
Why does the heart have one-way conduction?
-AV Node impulse delay (.12 seconds)
-Atrial muscles separated from ventricular muscles by fibrous barrier that insulate impulses other than through the AV bundle
How quickly is the conduction of the Large Purkinje Fibers?
VERY FAST (.03 seconds)
Purkinje fibers branch into the ---- and ----- ----- branches.
Right and Left bundles
What happens in a bundle branch block-- aka one of the Purkinje fibers branches is blocked
the other will still get excited......just takes longer
What is the normal pacemaker of the heart?
T/F: AV node and Purkinje fibers can self-excite.
true-- av node can fire without sa node... purkinje can self excited just suppppperrrrr slow / bradycardia
What is the rate of the SA node?
What is the rate of the AV node?
What is the rate of the purkinje fibers?
What is an ectopic pacemaker?
What is the result of these?
Pacemaker somewhere besides SA node;
Abnormal contraction of heart (ex atrial fibrillation)
What is one of the most useful dx tools in cardio?
What is the P wave?
What is the QRS complex?
What is the T wave?
What is the PR interval?
Time from when SA node fires until Purkinje fibers fire (.15-.16 seconds).... delay CAUSED BY THE AV NODE
what portion of the circulatory system has the lowest intravascular pressure
superior vena cava
What is the RR Interval?
Time between each impulse (HR)
What is the QT interval?
Length of time the ventricle cells are depolarized
What is the ST segment?
Time between ventricular depolarization and repolarization
What causes the aortic and pulmonic valves to close?
End of systole = relaxation of ventricles
What is the End-Diastolic Volume?
Amount of blood in the ventricles at the end of diastole
As intraventricular pressure exceeds the ------ pressure, ---- ----- pressure, and ------- pressure, the AV valves are pushed closed and the aortic and pulmonary valves are pushed open.
intra-atrial pressure, pulmonary artery pressure, and aortic (systolic) pressure
What percentage of End-Diastolic volume is ejected during Ventricular Ejection?
What is the End-Systolic Volume?
Amount of blood left in ventricles after contraction
What is the amount of End-Diastolic Volume that is ejected?
What is the actual volume of blood that is ejected during ventricular contraction?
What are the four phases of the cardiac cycle?
-Period of filling
-Period of ejection
What is Preload?
Another name for this?
Degree of tension on the muscles of the ventricles when they begin to contract;
What is Afterload?
What must it overcome?
Load or pressure against which the ventricles exert their contractile force to make stroke volume;
Pressure in Aorta - systolic blood pressure
Most of the medications for HTN work on what?
Preload and/or afterload
What is the Frank-Starling Mechanism?
Greater the heart muscle is stretched during filling, the greater the force and volume of contraction.
When would extra blood flow into the ventricles, causing the Frank-Starling Mechanism?
During Atrial Kick and increased Preload
What is Stroke volume?
Amount of blood ejected during ventricular contraction;
End-Diastolic Volume - End-Systolic Volume
What is HR?
Heart Rate = heart beats per minute
What can increase HR?
Increase (+ chronotrope): sympathetic input and hormones (thyroid)
Decrease (- chronotrope): Parasympathetic input
What is Total Peripheral Resistance?
Resistance placed upon the circulation by the ARTERIES
What are the factors of Total Peripheral Resistance?
-Total Blood Vessel Length
-Vessel Diameter (MAIN FACTOR)
What is Cardiac Output?
How much blood is ejected by ventricles per minute (normal = 5L/min)
What is the equation of Cardiac Output?
CO = HR x SV (stroke volume)
Ventricular fibrillation =
What are the factors affecting CO?
Increasing preload ----- CO.
Increasing afterload ----- CO.
T/F: Increased contractility increases CO.
True: more power = increase CO
T/F: HR can drop the Stroke Volume.
True: HR can increase CO but can drop the stroke volume.
BP = equation?
BP = CO x TPR
Is the SA Node intrinsic of extrinsic?
What are some extrinsic mechanisms that the body monitors CO and BP?
Rapid (due to ANS = neural): Neural ctrl of vessel diameter, HR, SV
Intermediate to long-term (due to chem/hormones): Renin-Angiotensin II system, Renin-Aldosterone system, ADH
Where do ANS impulses come from which ctrl rate and strength of cardiac contraction?
Parasymp = Vagus
Symp = from chain
Cardiac Output can be increased more than ----% by the sympathetic chain.
What is the mechanism of Beta-Blockers?
Block sympathetic input (thus decreasing CO)
Parasympathetic stimulation of the heart can decrease CO by ----%.
20-30%... by decreasing HR
What are three mechanisms for regulating BP or CO?
Where are baroreceptors?
How are they activated?
In arterial wall of carotid sinus and aortic arch;
Increased pressure stretches receptors and triggers signals to CNS
Path of signal from baroreceptors?
Sensory info enters Nucleus of Tractus Solitarius from Glossopharyngeal (Carotid) and Vagus (Aorta)
the higher the blood pressure the ____ the baroreceptors fire
Coronary arteries receive blood during -----
What is the Baroreceptor Reflex?
What does it result in?
Increased BP increases baroreceptor firing, triggering "feedback" signal that DECREASES BP.
Right coronary artery supplies
back of heart and right heart
Left coronary artery supplies
Left ventricular wall and anterior portion into the apex
What are chemoreceptors?
Cells that are sensitive to low O2, CO2, and H+;
In aorta and carotid
When arterial BP is low, what type of cells reacts to low O2, high CO2, and H+?
What is the process?
Signals transmitted via glossopharyngeal and vagus nerves to excite the VASOMOTOR center;
The ------ ------ responds to low lvls of BF like chemoreceptors.
This process is called ----- ---- -----.
CNS Ischemic Response (symp fibers in vasomotor center are stimulated which increases BP)
What is an example of a more-delayed but long-term management of CO and BP ctrl?
Renin-Angiotensin-Aldosterone (RAAS) System
What are Juxtaglomerular cells?
Where are they located?
Cells that respond to drop in BP by: releasing Renin & causing afferent arteriole vasodilation;
What does Renin do?
Works with Angiotensinogen to make Angiotensin II
Most MI's are caused by?
An atheroma ruptures and causes a clots
Purpose of Angiotensin II?
Increased symp act.
Increased H2O retention
Secretion of ADH from pituitary
Secretion of Aldosterone from adrenals
What does Aldosterone do?
Works at kidney to increase Na+ and H2O reabsorption.... increasing volume, preload, and CO & BP.
What does Antidiuretic Hormone do?
Increases H2O reabsorption, increasing blood volume, which increases preload, and CO & BP.
What triggers Antidiuretic Hormone to be secreted by the pituitary?
Hypovelmic and hyperosmolar blood
Smallest part of the circulation
What are the "control conduits" of circulation?
What does it do?
Makes sure that blood released into capillaries is at a rate that meets the needs of the tissues
T/F: Arterioles can close the vessel off completely and can dilate the vessel.
True: Arterioles are the "control conduits"
After blood enters the capillaries, it is collected by what?
What % of blood volume is in the systemic circulation?
What % of blood volume is in the venous system?
What % of blood is in the arterioles and capillaries?
What % of blood volume is in the heart and pulmonary circulation?
More in heart or lungs?
Wolfe-Parkinson-White Syndrome, what is it?
Pathway on the right side of the ventricle so there is pre-excitation
BP progressively falls throughout systemic circulation and is --- mmHg by time blood re-enters atrium.
T/F: Arteries are not distensible so they are often damaged by output of the heart.
False: Distensibility of the vascular systems accommodates output of heart so that vasculature is not damaged.
Which are most distensible: arteries or veins?
What is this purpose?
Allows blood to reservoir in veins
When pressure increases in vein due to elasticity, how does the vein reduce this pressure?
Why is this important?
It relaxes in a process called Delayed Compliance;
this is why the veins can be a reservoir: they relax instead of exploding (accommodate extra intravascular volume)
What are the functions of the veins?
-storage of blood
-propel blood back to heart
Which veins dump into the right atrium?
What kind of pressure is in the right atrium?
SVC & IVC;
CENTRAL VENOUS PRESSURE
What is the normal measurement of Central Venous Pressure? What does this reflect?
Why do px's with CHF have edema of LE's?
Right atrium pressure rises with back up of blood, which stresses the heart and increased peripheral venous pressure
T/F: Gravity has an affect on the venous system.
True: Gravity increases Peripheral Venous Pressure in the lower extremities.
What is the benefit of gravity on the venous pressure?
Can help drive the blood into larger veins of abdomen (especially when walking)
What is the venous pump?
"Muscle pump" is when blood is pushed vertically during walking
One-way valves are present in the (veins or arteries)?
Veins, to prevent backflow
Too much pressure in the veins can result in what?
What is the stroke volume?
End-diastolic volume - End-systolic volume
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