Chapter 15 Flashcards
what are the 4 components of the heart? *
- a pump to connect all components
- a high-pressure distribution circuit
- exchange vessels
- a low pressure collection and return circuit
what is the heart muscle called? what are some of its characteristics?
myocardium
- striated and interconnect in latticework fashion to allow the heart to function as a unit
- adapts to the type of exercise
what is the function of the right side of the heart?
receives blood returning from the body
pumps blood to lungs for aeration through pulmonary circulation
what is the function of the left side of the heart?
receives oxygenated blood from the lungs
pumps blood into thick-walled muscular aorta for distribution via systemic circulation
what are the 2 types of valves and their subdivisions?
Atrioventricular valves
- Tricuspid
- Bicuspid/mitral
Semilunar valves
- Pulmonary
- Aortic
what is the function of the tricuspid AV valve?
provides one-way blood flow from the right atrium to left ventricle
what is the function of the bicuspid/mitral AV valve?
provides one-way blood flow from the left atrium to left ventricle
what is the function of the semilunar valves?
prevents blood from flowing back into the heart between contractions
what is concentric hypertrophy? what type of exercise causes this?
When the walls of the heart become thicker allowing more blood to be pumped out
High intensity interval training
what is eccentric hypertrophy? what type of exercise causes this?
When the chambers of the heart become bigger allowing more blood to be held inside the heart
Aerobic exercise
what is the heart’s circulatory system called? where does it begin?
Coronary circulation
Arises immediately from the aorta
where does blood leave the tissues of the left ventricle through?
coronary sinus
where does blood leave the tissues of the right ventricle through?
anterior cardiac veins
what is the normal blood flow to the myocardium at rest?
200-250 mL/min
what are two factors that increase myocardial blood flow? *
- elevated myocardial metabolism dilates coronary vessels
2. increased aortic pressure during exercise forces a greater volume of blood into coronary circulation
what is extensive vascular perfusion?
When there is a supply of at least one capillary to each of the heart’s muscle fibers
what is tissue hypoxia? what are effects of tissue hypoxia?
A potent stimulus to myocardial blood flow
Can produce chest pains, or angina pectoris
how do you evaluate the adequacy of myocardial blood flow?
Exercise
example) cardiac stress test (graded exercise test)
what causes myocardial infarction?
A plaque or blood clot lodged in a coronary vessel which impairs normal heart function
what does an ECG represent?
The electrical activity of the heart during a cardiac cycle
what are the 3 steps of cardiac conduction?
- Impulse originates from the sinoatrial (SA) node in the right atrium and spreads across the atria causing them to contract
- The impulse passes to the atrioventricular (AV) node, travels along the AV bundle into its two branches, the right and left crus, and spreads into the ventricles causing them to contract
- Dissipation of the impulse causes the atria and ventricles to relax or dilate
what is the pathway of cardiac conduction? (8 steps)
- Sinoatrial (SA) node
- Interatrial septum
- Atrioventricular (AV) node
- Atrioventricular (AV) bundle (bundle of His)
- Right crus
- Left crus
- Interventricular septum
- Purkinje’s fibers
what does the p-wave represent? *
Depolarization of both atria before atria contract
what does the P-R segment represent?
The electrical transmission from the atria to ventricles
what does the QRS complex represent? *
Electrical changes from ventricular depolarization before ventricles contract
R indicates the initial positive deflection
Q indicates the negative deflection before the R-wave
S indicates the negative deflection following the R-wave
what does the S-T segment represent?
The earlier phase of repolarization that extends from the end of the QRS to the start of the T-wave
what does the T-wave represent? *
Repolarization of both ventricles during ventricular diastole
what does the Q-T interval represent?
Ventricular depolarization and repolarization
which phase of an ECG is able to detect heart issues?
ST segment, if elevated it may indicate a blockage
what are 3 characteristics of myocardial metabolism?
Relies almost exclusively on aerobic energy release
Contains greatest mitochondrial concentration of all tissues
Glucose, fatty acids, and lactate from glycolysis in skeletal muscle provide myocardial energy
where does majority of myocardial energy come at rest and during exercise?
At rest, free fatty acids
During exercise, oxidizing circulating lactate
what is the percentage of max heart rate that indicates moderate exercise?
75% max heart rate
what is the percentage of max heart rate that indicates intense exercise?
> 85% max heart rate
what is the rate-pressure product (RPP)?
Estimate of myocardial workload and VO2
what is the equation for rate-pressure product (RPP)? *
RPP = product of peak (SBP) x heart rate (HR)
what are characteristics of the arterial system?
High pressure tubing that propels oxygen-rich blood to tissues
Comprised of layers of connective tissue and smooth muscle
what is blood pressure?
The force of blood against arterial walls during a cardiac cycle
what does arterial blood pressure represent?
The combined effects of arterial blood flow per minute and resistance to flow in peripheral vasculature
what type of exercise can improve athletic performance and create new blood vessels?
High intensity interval training
what is the equation for blood pressure? *
Blood pressure = cardiac output x total peripheral resistance (TPR)
what is systolic blood pressure (SBP)?
Provides an estimate of work of heart and force blood exerts against arterial walls during systole
what is diastolic blood pressure (DBP)?
Relaxation phase of cardiac cycle
Indicates peripheral resistance or ease that blood flows from arterioles into capillaries
what is mean arterial pressure (MAP)? *
Average force exerted by blood against arterial wall during cardiac cycle
what are metarterioles?
Smaller and less muscular vessels that branch from arterioles
End in small blood vessels called capillaries that contain 6% of total blood volume
what are characteristics of capillaries?
Exchange site
A single layer of rolled up endothelial cells
Narrow, only one blood cell can squeeze through at a time
what is the life span for red blood cells?
20-70 days
what happens to red blood cells during HIIT?
The old red blood cells are destroyed so that the nice red blood cells are used
what are the 3 intrinsic controls?
- endothelium derived substances
- myogenic response to stretch
- metabolic factors
what are the 2 extrinsic controls?
- Neural (ex. Norepinephrine)
2. Hormonal (ex. Angiotensin II)
what is the function of sphincter constriction and relaxation?
Provides a means for blood flow regulation within a specific tissue to meet metabolic requirements
what are 2 factors that trigger precapillary sphincter relaxation to open more capillaries? **
- driving force of increased local blood pressure plus intrinsic neural control
- local metabolites produced in exercise (metaboreflex)
what is the metaboreflex? *
an autonomic reflex that signals the supply of O2 and nutrients, not meeting the demand of tissue, the signal causes the sphincter to open up causing vasodilation
what is the body’s largest vein and what is its function?
Inferior vena cava
Returns blood to the right atrium from the abdomen, pelvis, and lower extremities
how is blood able to return back to the heart?
Veins contain one way valves that allow blood to flow in one direction towards the heart
The alternating compression and relaxation of veins and one-way valves provide a “milking” action that propels blood back to the heart
what is hypertension?
Systolic or diastolic pressure that exceeds recommended values
what are the effects of hypertension if left untreated?
Can lead to arteriosclerosis, heart disease, stroke, and kidney failure
Artery becomes resistant to blood flow because of arterial hardening with fatty material in walls and neural hyperactivity or kidney malfunction
what are 5 effective treatment options for hypertension?
- Lose excessive weight
- Follow a DASH diet
- Daily physical activity
- Limit sodium
- Limit alcohol
