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SP MCAT Biology > Cardiovascular System > Flashcards

Flashcards in Cardiovascular System Deck (108)
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1

Heart

-primarily composed of cardiac muscle
-right side of heart accepts deoxygenated blood returning from the body and moves it to the lungs via the pulmonary arteries (pulmonary circulation)
-left side of heart receives oxygenated blood from the lungs via the pulmonary veins and pumps it out to the body through the aorta (systemic circulation)

2

Atria

thin-walled structures where blood is received from either the venae cavae (deoxygenated blood entering the the right heart) or the pulmonary veins (oxygenated blood entering the left heart)

3

Ventricles

-receive blood from the atria
-after they are filled they contract to send blood to the lungs and systemic circulation
-far more muscular than the atria

4

What valves separate the atria and ventricles?

Atrioventricular Valves

5

Atrioventricular Valves

*LAB RAT*
Left Atrium = Bicuspid
Right Atrium = Tricuspid

6

What valves separate the ventricles from the vasculature?

Semilunar Valves

7

What valve separates the right ventricle from the pulmonary circulation?

Pulmonary Valve (three leaflets)

8

What valve separates the left ventricle from the aorta?

Aortic Valve (three leaflets)

9

Which side of the heart is more muscular?

the left heart -- because it has to pump blood into systemic circulation

10

List the pathway of electrical conduction in the heart

1. Sinoatrial (SA) Node
2. Atrioventricular (AV) Node
3. Bundle of His
4. Purkinje Fibers

11

SA Node

-small collection of cells located in the wall
-generates 60-100 beats per minute, even if all innervation to the heart is cut
-does not require neurological input, as neurological input only functions in speeding up and slowing down rate of contraction
-depolarization causes the two atria to contract simultaneously

12

AV Node

-sits at junction of the atria and ventricles
-signal is delayed here to allow the ventricles to fill completely before they contract

13

Intercalated Discs

-connect muscle cells in the ventricles
-contain many gap junctions directly connecting the cytoplasm if adjacent cells, thereby allowing for coordinated ventricular contraction

14

The circulatory system is under ____ control

autonomic

15

What are the effects of sympathetic signals to the heart?

increased heart rate and increased contractility of cardiac muscle

16

What are the effects of parasympathetic signals to the heart?

slowed down heart rate

17

What nerve sends parasympathetic signals to the heart?

Vagus Nerve

18

Systole

-ventricular contraction and closure of the AV valves occurs (ventricular pressure > atrial pressure), and blood is pumped out of the ventricles

19

Diastole

-heart is relaxed
-semilunar valves are closed (aortic/pulmonary pressure > ventricular pressure), and blood from the atria fills the ventricles
-ventricular pressure continues to increase as blood enters the relaxed ventricle from atrium
-at end of this phase SA Node discharges and atria depolarize, leading to contraction of atria thus increasing atrial pressure which forces a small push of blood volume into ventricle ("Atrial Kick")

20

Contraction of the ventricles generates a ____ pressure during systole, whereas their relaxation during diastole causes the pressure to ____.

-higher
-decrease

21

What allows the vessels to maintain sufficient pressure while the ventricular muscles are relaxed?

the elasticity of the walls of the large arteries

22

Cardiac Output

-the total blood volume pumped by a ventricle in a minute (volume of blood pumping through each ventricle is the same)
-about 5 liters per minute
- CO = HR x SV

23

HR

-heart rate
-beats / minute

24

SV

-stroke volume
-volume of blood pumper per beat

25

"Lub"

-first heart sound
-closure of AV valves
-occurs at beginning of systole (ventricles beginning to contract, pressures above atrial pressure, blood wants to flow back into atria but valves prevent this)

26

"Dub"

-second heart sound
-closure of SL valves
-occurs at beginning of diastole

27

What causes valves in the heart to open and close?

pressure differences

28

What type of cells line all blood vessels?

Endothelial Cells -- help maintain the vessel by releasing chemicals that aid in vasodilation and vasoconstriction, also allow white blood cells to pass through the vessel wall and into the tissues during an inflammatory response

29

Arteries

*Arteries carry blood Away from the heart*
-most arteries contain oxygenated blood, but pulmonary arteries and umbilical arteries contain deoxygenated blood
-highly muscular and elastic, creating tremendous resistance to the flow of blood
-elastic recoil from their walls maintains a high pressure and forces blood forward
-composed of connective tissue, endothelium and smooth muscle

30

Arterioles

-arteries branch into these
-high resistance
-strong contractile capability
-determine how fast blood can move through circuit
-composed of endothelium and smooth muscle