EXAM2- Review of CV Anatomy & Physiology Flashcards
the circulatory system works with what system
pulmonary system
names for circulatory + pulmonary system when working together
-cardiopulmonary system
-cardiorespiratory system
3 purposes of the cardiorespiratory system
-transport O2 + nutrients to tissues
-removal of CO2 wastes from tissues
-regulation of body temperature
when we exercise, our vessels dilate/constrict
dilate
-because body temp goes up
in a cold setting, our vessels dilate/constrict
constrict
-our body initiates shivering, rapid muscle contraction to give off heat)
-constrict to keep heat within the body
heart
creates pressure to pump blood
arteries + arterioles
carry blood away from the heart
veins + venules
carry blood toward the heart
capillaries
responsible for all exchange of O2, CO2, + nutrients with tissues
blue part of the heart represents
deoxygenated blood
**be able to label R atrium, L atrium, R ventricle, L ventricle, + interventricular septum on slide 4
left ventricle
pushes blood to the rest of the body
top segments of heart
R atrium + L atrium
bottom segments of heart
R ventricle + L ventricle
3 parts of the heart wall
-epicardium
-myocardium
-endocardium
myocardium
“muscle” responsible for heart contraction
-essentially, the muscle of the heart
myocardium receives blood supply via ____
coronary arteries
coronary arteries are responsible for
meeting high demands of oxygen + nutrients
myocardial infarction (MI)
aka a heart attack
-blockage in coronary blood flow results in cell damage
-cardiac tissue dies; once cardiac tissue is dead, we cannot do anything to regenerate it, which can have extreme effects on a person’s ability to function after a MI
what protects against heart damage during a MI
exercise training
-individuals that exercise + have an MI are much more likely to survive + function after
epicardium is also called
visceral pericardium
epicardium characteristics
serous membrane including blood capillaries, lymph capillaries, + nerve fibers
epicardium function
serves as lubricative outer covering
myocardium characteristics
cardiac muscle tissue separated by connective tissues and includes blood capillaries, lymph capillaries + nerve fibers
myocardium function
provides muscular contractions that eject blood from the heart chambers
endocardium characteristics
endothelial tissue + a thick subendothelial layer of elastic + collagenous fibers
endocardium function
serves as protective inner lining of the chambers + valves
blood is made up of what 2 things
-plasma
-cells
plasma
liquid portion of blood
-contains ions, proteins, hormones
3 types of blood cells
-RBC
-WBC
-platelets
red blood cells (RBC)
contain hemoglobin to carry oxygen
the largest % of cells in the blood are what
red blood cells
white blood cells
important in preventing infection
platelets
important in blood clotting
-if you get a scrape, helps scab
hematocrit
% of blood composed of RBC
centrifuge
machine that breaks blood into its 2 components (plasma + blood cells)
if someone has an infection, what levels do we expect to go up
WBC
typical hemaocrit of blood
42%
systole
-contraction phase
-ejection of blood
how much blood is ejected from ventricles per beat
2/3 blood
why is 1/3 blood left in ventricle after contraction
because you must have a little blood leftover to maintain the structural integrity of the ventricle
-if we took all the blood out, the ventricle would collapse
diastole
-relaxation phase
-filling with blood
at rest, diastole or systole is longer
diastole
-makes sense because our heart wants to do least work required
**during exercise, what happens to systole + diastole
both become shorter
-the higher the intensity of the exercise, the more the phases will shorten
pressure in diastole
pressure in ventricles is LOW
-things want to travel from high to low pressure, so having low pressure in ventricle during diastole facilitates it filling up with blood
during diastole, ventricles are filling with blood from ____
atria
pressure in systole
pressure in ventricles rises
during systole, blood is ejected in ____
pulmonary + systemic circulation
first heart sound
systole
-closing of AV valves
second heart sound
diastole
-closing of aortic + pulmonary valves
how is arterial BP expressed
systolic/diastole
normal BP
<120/<80 mmHg
systolic pressure
pressure generated during ventricular contraction
diastolic pressure
pressure in arteries during cardiac relaxation
pulse pressure
difference between systolic + diastolic
ex: 120/80
pulse pressure = 120-80 = 40
what would a BP of 120/120 mean
no resting period for the heart because pressure is staying consistent the entire time
mean arterial pressure (MAP)
average pressure in the arteries during cardiac cycle AT REST
MAP equation
MAP = DBP + (0.33)(SBP-DBP)
what does contraction of the heart depend on
electrical stimulation of the myocardium
describe heart contraction
automatic contraction
-need for electrical stimulation
describe skeletal muscle contraction
voluntary contraction
-brain must send signal to do so
sinoatrial node (SA node)
-pacemaker
-initiates depolarization
atrioventricular node (AV node)
-passes depolarization to ventricles
-brief delay (called AV delay) to allow for ventricular filling (blood transfer from atria to ventricle)
why does AV delay occur
so that atria + ventricles do not contract at same time
-if they were stimulated at the same time, no blood would move
bundle branches extend from
AV node
bundle branches
connect atria to L + R ventricle
-splits into 2 so the wave of depolarization can affect L + R side of heart
purkinje fibers
spread depolarization throughout ventricles
4 steps of conduction system of the heart
- APs originate in the SA node (the pacemaker) + travel across the wall of the atrium from the SA node to the AV node
- APs pass through the AV node + along the AV bundle, which extends from the AV node, through the fibrous skeleton, into the interventricular septum
- the AV bundle divides into R + L bundle branches, + APs descend to the apex of each ventricle along the bundle branches
- APs are carreid by the purkinje fibers from the bundle branches to the ventricular walls
regulation of HR
a mix/coordination between parasympathetic + sympathetic nervous system
parasympathetic nervous system regulates HR via what
vagus nerve
how does parasympathetic nervous system regulate HR
-slows HR by inhibiting SA + AV node
-decrease in parasympathetic tone = increase in HR (typically causes rise in HR up to 100 bpm)
sympathetic nervous system regulates HR via what
cardiac accelerator nerves
how does sympathetic nervous system regulate HR
increases HR by stimulating SA + AV node (typically causes rise in HR BEYOND 100 bpm)
there is a decrease/increase in HR at onset of exercise
increase
describe increase in HR at onset of exercise
-INITIAL increase (at onset) is due to parasympathetic withdrawal
-LATER increase (a few seconds later) is due to increased sympathetic stimulation
**see diagram on slide 16
what happens when parasympathetic nerve is stimulated
-causes release of ACh in little junctions
-ACh then binds to receptors on SA node, which will inhibit HR
-when you need HR to go down, that is when parasympathetic kicks in
what happens when sympathetic nerve is stimulated
-also goes to SA node
-when cardiac accelerator nerves are stimulated, they release norepinephrine into gap
-stimulatory, will increase HR
heart rate variability
the time between heart beats
HR variability is the standard deviation of what on an EKG
R-R interval
HR variability is the balance between what
between SNS + PNS
wide/high variation in HR variation is good/bad
higher HR variability = good
-tells us that PNS kicks in when it needs to + same with SNS
wide variation in HRV reflects ____
autonomic balance
-considered healthy
low HRV is a predictor of what
cardiovascular morbidity + mortality
-in patients with existing cardiovascular disease
what does low HR variability tell us
either PNS or SNS is overriding
cardiac output
the amount of blood pumped by the heart each minute
cardiac output is the product of what
HR x SV
(heart rate x stroke volume)
cardiac output equation
Q = HR x SV
heart rate
number of beats per minute
stroke volume
amount of blood ejected in each beat
what 2 things does cardiac output depend on
-training state
-gender
males/females have higher cardiac output
males
-because bigger build so typically need more
one of the key benefits of training
greater cardiac output
end-diastolic volume (EDV)
volume of blood in ventricles at the end of diastole
-basically how good your ventricle is at filling with blood
what is another name for EDV
preload
the more EDV you have…
greater contraction
-because more stretch (when ventricle is optimally filled) which facilitates a stronger contraction
Frank-Starling mechanism
greater EDV results in a more forceful contraction
-due to stretch of ventricles
what is EDV dependent on
venous return
venous return
how much blood is coming into the heart
what 3 things increase venous return
-venoconstriction
-skeletal muscle pump
-respiratory pump
how does venoconstriction increase venous return
increased pressure in veins
how does skeletal muscle pump increase venous return
-rhythmic skeletal muscle contractions force blood in the veins toward the heart
-one-way valves in veins prevent backflow of blood
how does respiratory pump increase venous return
changes in thoracic pressure pull blood toward heart
stroke volume is dependent on what 3 factors
-EDV
-MAP
-strength of ventricular contraction (contractility)
how is stroke volume dependent on MAP (average aortic BP)
pressure of heart must pump against to eject blood (afterload)
-meal arterial pressure
how is stroke volume dependent on strength of ventricular contraction (contractility)
enhanced by:
-circulating epinephrine + norepinephrine
-direct sympathetic stimulation of heart
oxygen demand by muscles during exercise is ___x greater than at rest
15-25x greater
what 2 ways is increased O2 delivery accomplished by
-increased cardiac output
-redistribution of blood flow (from inactive organs to working skeletal muscle)
as soon as we begin to exert ourselves, ___ demands increase
oxygen
cardiac output increases due to what 2 things
-increased HR
-increased SV
both of these increase during exercise
describe increase in HR during exercise
linear increase until reaches max
how to calculate max HR
220 - age for adults
-KNOW there is an equation for children, but don’t need to know specific equation
describe increase in SV during exercise
increase, then plateau at 40-60% VO2 max
-no plateau in HIGHLY trained subjected
what does plateau in SV mean
after 40-60%, if cardiac output continues to increase it must come from increased HR
**see slide 23 graphs
circulatory responses to exercise
changes in HR + BP
circulatory responses to exercise (changes in HR + BP) depend on what 4 things
-type, intensity, + duration of exercise
-environmental condition
-emotional influence
-training status
there is an equal/more/less exaggerated response if you are hitting lower vs upper body
LESS exaggerated response for lower body
what happens anytime heat/humidity becomes part of the equation…
we get a very different response + can disregard typical responses
one of the key benefits of being TRAINED (in regards to HR + BP)
we see a LOWER change in HR + BP
at the same oxygen uptake, arm work results in higher of what 2 things
-HR
-BP
at the same oxygen uptake, arm work results in higher HR due to what
higher sympathetic stimulation
at the same oxygen uptake, arm work results in higher BP due to what
vasocontriction of large inactive muscle mass
when you hit lower body, which muscles constrict
upper body muscles
-opposite is true for when you hit upper body
steady state
physiologically means that body is able to meet demands being placed on it
transition from rest to exercise- what occurs at the onset of exercise
-rapid increase in HR, SV, cardiac output
-plateau in submaximal (below lactate threshold) exercise
transition from exercise to recovery- what occurs during recovery
-decrease in HR, SV, + cardiac output toward resting levels
-depends on:
* duration + intensity of exercise
* training state of subject
trained vs untrained people in recovery
trained people return to recovery much faster than regular individuals
**see graph on slide 27
regular exercise is ____
cardioprotective
2 reasons why regular exercise is cardioprotective
-reduces incidence of heart attacks
-improves survival from heart attack
what does exercise reduce during a heart attack
reduces amount of myocardial damage from heart attack
how does exercise reduce the amount of myocardial damage from heart attack
-improvements in heart’s antioxidant capacity (ability to remove free radicals, repair tissue damage, etc.)
-improved function of ATP-sensitive potassium channels
when tissues are more sensitive to ATP, what does this mean
they require LESS ATP
-beneficial to be better at using ATP in the context of a heart attack
-when cells become necrotic/start to die, heart uses a ton of ATP to counteract the dying cells
endurance exercise protects against cardiac injury during heart attack graph- how did untrained compare to trained
roughly 1/3 of untrained damage occurred in trained
when heart tissue dies can it be regenerated
no, nothing can be done to regenerate necrotic tissue
**see graph on slide 30
