Cardiovascular Flashcards
Cardiovascular system works with:
pulmonary system
Purpose of cardiovascular system:
- Transport O2 and nutrients to tissues
- Removal of CO2 and other waste products
- Regulation of body temp
- Transportation of hormones
Blood is very good at transporting heat; it helps remove heat from body during:
exercise
The heart creates pressure to pump:
blood
Arteries carry blood away from the:
heart
Arterioles are small arteries capable of:
constricting/changing their size to affect blood flow
Capillaries exchange O2, CO2 and nutrients with:
tissues
Venules are small veins with:
slight elasticity
Veins carry blood toward the:
heart
Structure of the heart:
4 chambers; right and left atriums; right and left ventricles; 4 valves
The right and left atriums receive:
blood
Right and left ventricles push ___ out
blood
What are the four valves of the heart?
R and L AV valves, R and L semilunar valves
semilunar valves open when:
pressure increases on one side of the valve
Semilunar valves are:
one-way
Major vessels of the heart:
- inferior and superior vena cava
- pulmonary artery
- aortic artery
Pulmonary Circuit:
-right side of the heart (collects deoxygenated blood from the body)
- pumps deoxygenated blood to the lungs via pulmonary arteries
- returns oxygenated blood to the left side of the heart via pulmonary veins
Systemic Circuit:
- Left side of the heart (brings oxygenated blood from lungs and gives it to the body)
- pumps oxygenated blood to the whole body via arteries
- returns deoxygenated blood to the right side of the heart via veins
Pulmonary circulation:
pumps deoxygenated blood from body to lungs;
RA > AV valve > RV > pulmonary valve > pulmonary arteries > lungs > pulmonary valve > LA
Systemic circulation:
pumps oxygenated blood from lungs to body;
LA > mitral valve > LV > aortic valve > aorta > body > superior, inferior vena cava > RA
Myocardium is the:
heart wall; 3 layers
What are the three layers of the myocardium?
- epicardium (outside)
- myocardium (performs contractions)
- endocardium (inner layer of protection, smooth layer for blood to move)
Coronary arteries supply:
blood to heart
Myocardial Infarction (heart attack) happens when:
blockage in coronary blood flow results in cell damage
Exercise training ___ the risk of having a heart attack
decreases
Both heart and skeletal muscles have:
contractile proteins (actin and myosin), z-discs (walls of contractile portion of the heart), and striated structure
What is the shape of a heart muscle?
shorter than skeletal muscle fibers and branching
How many Nuclei are in heart muscles?
single
Do heart muscles have cellular junctions?
yes - intercalated discs
What kind of connective tissue does heart muscle have?
endomysium
Intercalated disc carries:
electrical signal; happens in certain order
What is the primary form of energy production in a heart muscle?
aerobic
What is the calcium source for contraction in a heart muscle?
sarcoplasmic reticulum and extracellular calcium
Does heart muscle move voluntarily or involuntarily?
involuntarily
What is the regeneration potential of heart muscle?
none - no satellite cells present
The Cardiac Cycle refers to:
the repeating patterns of contraction and relaxation of the heart
Systole:
- contraction phase
- ejection of blood (approx 2/3 of blood is ejected from ventricles per beat)
Diastole:
- relaxation phase
- filling with blood
At rest, diastolic time is ___ than systolic time
longer
During exercise, what happens to the duration of both systolic and diastolic?
both durations are decreased
At rest, how long does systole and diastole take?
.3 and .5 seconds, respectively
during exercise, how long does systole and diastole take?
.2 and .13 seconds, respectively
During diastole, the pressure in the ventricles is:
low
AV valves open when:
ventricular P < atrial P
During systole, the pressure in the ventricles:
increase
During systole, blood is ejected:
in pulmonary and systemic circulation
semilunar valves open when:
ventricular P > aortic P
What are the first and second heart sounds?
first: closing of AV valves
second: closing of aortic and pulmonary valves
Arterial blood pressure is expressed as:
systolic/diastolic
Normal blood pressure is:
120/80 mmHg
Systolic pressure:
pressure generated during ventricular contraction
Diastolic pressure:
pressure in arteries during ventricular relaxation
Pulse pressure:
systolic - diastolic
when inflating the cuff while taking blood pressure, the cuff pressure is raised to:
200 mmHg, which closes the vessel
When taking blood pressure, after releasing the cuff pressure, what do you hear?
turbulent 1st korotkoff sounds
When taking blood pressure, when do you start recording cuff pressure?
at first sound, marks systolic BP
When taking blood pressure, when do you stop recording cuff pressure?
at the last korotkoff sound, marks diastolic BP
At the last korotkoff sound when taking BP, that indicates the vessel is:
fully opened
Hypertension numbers:
SBP > 140 mmHg
DBP > 90 mmHg
*only need one to be hyper
Hypotension numbers:
SBP < 90 mmHg
DBP < 60 mmHg
*only need one to be hypo
Determinants of MAP
- cardiac output (amount of blood getting kicked out per min)
- total vascular resistance
Short-term regulation of arterial blood pressure
- sympathetic nervous system (SNS)
- baroreceptors in aorta and carotid arteries
increase in BP = decrease SNS activity
decrease in BP = increase SNS activity
Long-term regulation of arterial blood pressure
Kidneys via control of blood volume; affects total vascular resistance
Contraction of the heart depends on:
electrical stimulation of the myocardium
Sinoatrial node (SA node) is the ___ and initiates ___
- pacemaker (sets pace, if fails, AV node takes over)
- initiates depolarization
Atrioventricular node (AV node) passes ___ signal to ventricles and causes a brief delay allowing for ___ _____
- passes depolarization (signal) to ventricles
- brief delay to allow for ventricular filling
Bundle branches connect atria to:
left and right ventricle
purkinje fibers spread wave of ____ throughout ventricles
depolarization
What are the three main wavelengths of an electrocardiogram (ECG)?
P wave, QRS complex, T wave
P wave
atrial depolarization (contraction signal)
QRS complex:
ventricular depolarization and atrial repolarization (reset membrane potential to relaxed state)
T wave
ventricular repolarization (going back to resting membrane)
ECG abnormalities may indicate:
coronary heart disease
ST-segment depression on an ECG can indicate:
myocardial ischemia (lack of blood flow)
Cardiac output (Q) =
the amount of blood pumped by the heart each minute
Cardiac output is the product of:
heart rate and stroke volume
what is stroke volume?
amount of blood ejected in each beat
what is heart beat?
number of beats per min
Trained individuals have a higher cardiac output, meaning:
the heart doesn’t need to work so hard, their heart muscles are more efficient
How does the parasympathetic nervous system regulate heart rate?
- via vagus nerve
- slow HR by inhibiting SA and AV node
- low resting HR due to parasympathetic tone
how does the sympathetic nervous system regulate heart rate?
- via cardiac accelerator nerves
- increases HR by stimulating SA and AV
Initial increase in HR at onset of exercise is due to:
parasympathetic withdrawal (up to 100 bpm)
later increase in HR during exercise is due to:
SNS outflow
How does the end-diastolic volume (EDV) regulate stroke volume?
- volume of blood in the ventricles at the end of a diastole (pre-load)
- frank-starling mechanism (greater EDV results in a more forceful contraction due to stretch of ventricles)
How does average aortic blood pressure regulate stroke volume?
pressure the heart must pump against to eject blood (afterload); has the potential to lower SV
How does the strength of the ventricular contraction regulate stroke volume?
ventricular contraction is enhanced by circulating epinephrine and norepinephrine, direct sympathetic stimulation of the heart
End-diastolic volume (EDV) is dependent on:
venous return
venous return is increased by:
- vasoconstriction via SNS
- skeletal muscle pump
- respiratory pump
how does the skeletal muscle pump increase venous return?
- rhythmic skeletal muscle contraction force blood in the extremities toward the heart
- one way valves prevent backflow
how does the respiratory pump increase venous return?
changes in thoracic pressure pull blood toward heart
What is the relationship between EDV and SV?
positive, when one increases, the other increases
Cardiac output is influenced by:
cardiac rate and stoke volume
cardiac rate is influenced by:
parasympathetic and sympathetic nerves
stroke volume is influenced by:
contraction strength, end-diastolic volume, mean arterial pressure
Plasma:
- liquid portion of blood
- contains ions, proteins, hormones, and platelets
- majority of blood is plasma
- if too low blood becomes more viscous (dehydration can lower by 10%)
Blood cells:
red blood cells (RBC), white blood cells (WBC) and platelets
Red blood cells (RBC):
contain hemoglobin to carry O2
White blood cells (WBC):
important in preventing infection
Platelets:
blood clotting
Hematocrit:
percentage of blood composed of cells
blood flow is directly proportional to:
the pressure difference between the two ends of the system
blood flow is inversely proportional to:
resistance
blood flow =
change in pressure / resistance
resistance depends upon:
- length of the vessel
- viscosity of the blood
- radius of vessel (great influence on resistance)
sources of vascular resistance
- MAP decreases throughout the systemic circulation
- largest BP drop occurs across the arterioles (arterioles called “resistance vessels”)
will length of vessel and viscosity of blood change when starting exercise?
no, but can change radius; viscosity and length are long-term adaptations
How does pressure change across the systemic circulation?
pressure decreases as getting closer back to heart
O2 demand by muscles increases during exercise by how much?
~ 15 to 25 times greater than rest
increased O2 delivery accomplished by:
- increased cardiac output (Q)
- redistribution of blood flow (from inactive organs to working skeletal msucle)
at rest, blood flow is distributed:
evenly
during exercise, blood flow is distributed:
mostly to the heart and brain, only distributed where it is needed
Cardiac output increases during exercise due to:
increased HR
SV increases during exercise, then plateaus at:
- plateau at 40 to 60% VO2 max
- no plateau in higher trained subjects
Changes in arteriovenous difference (a-v O2 difference) during exercise
increases during exercise due to higher O2 uptake in tissues (used for ATP production)
Fick equation:
relationship between cardiac output (Q), VO2 difference, and VO2: VO2 = Q x a-v O2 difference
changes in HR and BP during exercise depend on:
- type, intensity, and duration of exercise
- environmental conditions
transition from rest to exercise causes a rapid increase in:
HR, SV, and cardiac output
Transition from exercise to recovery causes a decrease in:
HR, SV, and cardiac output towards resting levels (depends on duration and intensity of exercise, training state of the individual)
How does incremental exercise affect heart rate and cardiac output?
- increases linearly with increased work rate
- both reach a plateau at 100% VO2 max
How does incremental exercise affect blood pressure?
mean arterial pressure (MAP) increases linearly (SBP increases, DBP remains fairly constant
recovery of heart rate and blood pressure between bouts during intermittent exercise depend on:
- individual fitness level
- temp and humidity
- duration and intensity of exercise
near maximal HR values are possible during intermittent exercise when:
it is heavy-intensity
during prolonged exercise, cardiac output is maintained due to:
- gradual decrease in stroke volume
- dehydration and reduced plasma volume
gradual increase in heart rate during prolonged exercise (particularly in heat) causes:
cardiovascular drift (increased in HR and decreased in SV)
Endurance training increases:
maximal stroke volume
endurance training increases maximal stroke volume by:
- increasing pre-load (EDV), increasing plasma volume, increasing venous return, increasing ventricular volume
- decreasing afterload (TPR), decreasing arterial constriction, increasing maximal muscle blood flow with no change in mean arterial pressure
- increasing contractility
endurance training-induced changes occur rapidly, such as:
11% increase in plasma volume, 7% increase VO2 max, and 10% increase in stroke volume within first six days of endurance training
Training-induced increases in a-vO2 difference:
- muscle blood flow increases (decrease SNS vasoconstriction)
- improved ability of muscle fibers to extract and utilize O2 from the blood (increase capillary density and increase mitochondrial number)
