Anatomy II Exam I - CARDIOVASCULAR SYSTEM

arteries carry blood which direction?

away from the heart

veins carry blood which direction?

toward the heart

pulmonary circuit

carries deoxygenated blood from heart to lungs, returning oxygenated blood back to the heart

systemic circuit

carries oxygenated blood from the heart to the body, returning deoxygenated blood to the heart

describe the different coverings of the heart & their function

fibrous pericardium : tough outer layer, protects heart

serous pericardium : parietal (lines fibroud layer), visceral (epicardium, covers heart surface

pericardial cavity : contains fluid to reduce friction

what are the three layers of the heart wall?

epicardium, myocardium, endocardium

epicardium

outer layer of the heart wall made of connective tissue that functions to protect the heart

myocardium

middle layer of the heart wall made of cardiac muscle that functions to contract the heart

endocardium

innermost layer of the heart wall made of endothelium that functions to line the heart

what are the four chambers of the heart? what direction do they pump blood?

right atrium: receives deoxygenated blood from the body and pumps blood to the right ventricle.

right ventricle: pumps blood to the lungs

left atrium: receives oxygenated blood from the lungs, pumps blood to the left ventricle

left ventricle: pumps blood to the body

where is the tricuspid valve located?

the right atrium flowing into the right ventricle

where is the bicuspid / mitral valve located?

left atrium flowing into the left ventricle

where is the pulmonary semilunar valve?

flow from the right ventricle to the pulmonary artery

where is the aortic semilunar valve?

flow from the left ventricle to the aorta

how is blood supplied to the heart?

the right and left coronary arteries branch from the aorta to supply the myocardium

systole

contraction

diastole

relaxation and filling

what are the events of the cardiac cycle?

1) atrial systole while ventricular diastole

2) ventricular systole while atrial diastole

3) both chambers relax briefly

what are the main characteristics of cardiac muscle cells?

intercalated discs - striated - single nucleus - involuntary - has t-tubule openings

what is the pacemaker of the heart’s cardiac conduction system?

SA node

cardiac conduction system

1. SA node (pacemaker)

2. atrial syncytium

3. junctional fibers

4. AV node

5. AV bundle

6. bundle branches

7. purkinje fibers

8. ventricular synctium

what movement does each wave of an ECG display?

P wave: atrial depolarization (just prior to contraction)

QRS complex: ventricular depolarization (just prior to contraction)

T wave: ventricular repolarization (just prior to relaxation)

the “lubb” sound of the heart is a result of which valves closing and what movement is happening?

AV valves, ventricular systole

the “dubb” sound of the heart is a result of which vales closing and what movement is happening?

the pulmonary and aortic semilunar valves close. occurs during the ventricular diastole

how does the ECG correlate to heart sounds?

QRS: ventricular contraction → “lubb”

T wave: ventricular relaxation → “dubb”

during systole of each chamber type, does pressure increase or decrease?

increase

how do valves open and close?

pressure differences

heart rate changes occur due to factors that influence the __________

SA node

parasympathetic impulses reach the heart through which nerve?

Vagus

does the parasympathetic system increase or decrease heart rate? sympathetic system?

parasympathetic: decrease

sympathetic: increase

through which type of nerve do sympathetic impulses reach the heart?

accelerator nerves

baroreceptor reflex

maintaining blood

cardioinhibitory reflex

lowers heart rate and blood pressure

cardioaccelerator reflex

increases heart rate and force of contraction to lower venous pressure

what are the types of blood vessels?

arteries, arterioles, capillaries, venules, veins

arteries - describe & list function(s)

thick, strong walls. transport blood under high pressure and give rise to smaller arterioles

what are the three layers of arteries?

tunica interna, tunica media, tunica externa

metarterioles

branches that join capillaries or veins

does vasoconstriction result from a stimulation or an inhibition of the vasomotor impulse?

stimulation

capillary - describe and give function(s)

smallest diameter blood vessel that connects arterioles to smallest venules. extensions of inner linings of arterioles, semipermeable layer through which substances in the blood are exchanged for substances in the tissue fluid

fenestrated capillary

“leaky” : glands secrete through holes

sinusoidal capillary

found in the liver, spleen, and bone marrow, there are large cavities in the capillary and there is an incomplete basement membrane

list some differences between veins and arteries

arteries have high pressure, veins have low pressure. arteries have thick walls, veins have thin walls. arteries do not have valves, veins have valves

how do valves ensure blood returns to the heart?

they prevent backflow and work with muscle contractions

blood pressure

force the blood exerts against the inner walls of the blood vessels

systolic pressure

maximum pressure achieved during ventricular contraction

diastolic pressure

lowest pressure remaining in arteries during ventricular relaxation

what factors influence BP?

blood volume, heart rate, stroke volume, blood viscosity, peripheral resistance

how do you calculate cardiac output?

multiplying heart rate by stroke volume

CO = SV x HR

stroke volume

amount of blood discharged with each heartbeat, typically around 70 mL

cardiac output

amount of blood discharged from ventricle per minute

peripheral resistance

force of friction between blood and the walls of blood vessels

how to calculate blood pressure?

product of cardiac output and peripheral resistance

BP = CO x PR

Frank-Starling Law of the Heart

more ventricular filling leads to a stronger contraction