Circulatory Flashcards Preview

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Flashcards in Circulatory Deck (44):
1

What is perfusion?

flow of blood through tissue

2

What is Ischemia?

inadequate blood flow. Waste builds up

3

what is Hypoxia?

reduced supply of oxygen in the blood

4

Does exchange happen in arterioles?

No

5

What is angiogenesis?

Formation of new blood vessels by proliferation of epithelial cells

6

What prevents backflow of blood?

Venous Valves

7

What happens during diastole?

ventricles relax, blood flows in from atria. Atria contract

8

What happens during systole?

ventricles contract, AV valves shut

9

Which is longer Diastole or Systole?

Diastole

10

What is stroke volume?

amount of blood pumped with each systole

11

what is cardiac output?

total amount of blood pumped per minute

12

What does cardiac output equal?

stroke volume x heart rate

13

Is the cardiac output the same in the left and right ventricles?

Yes. So backup does not occur

14

What are ways to increase cardiac output?

increase venous return and arterioles dilating

15

What are fast sodium channels?

Open first in response to depolarization to allow sodium to enter

16

What are slow calcium channels?

Open in response to threshold voltage and allow calcium down its gradient. Stay open longer creating plateau phase

17

What feature maximizes calcium entry into cardiac muscle cells once an action potential arrives?

T-Tubules

18

In the heart what releases calcium?

Sarcoplasmic reticulum

19

Which have longer refractory periods neurons or cardiac muscle?

Cardiac muscle

20

What are the three phases of the SA node?

Phase 0, Phase 3, Phase 4

21

Why does the SA node have unstable resting potential?

Due to phase 4 and sodium leak channels allowing sodium in to push for threshold

22

What happens at phase 0?

VG Calcium channels open

23

What happens at phase 3?

Repolarization. Closure of Calcium channels and opening of potassium channels.

24

Which node sets the rate of heart contraction?

SA node

25

What happens during phase 1?

Sodium channels inactivate, Potassium Channels open, Potassium efflux

26

What happens during phase 2?

Plateau. Calcium channels open, Calcium influx, Potassium efflux

27

What is the driving force in blood flow?

Difference in pressure from arteries to veins

28

What does Ohm's Law tell about blood flow?

In order to change blood flow, you must change pressure or resistance

29

How can pressure be varied?

Changing force or rate of contraction

30

What is the determinant of resistance in vessels?

Precapillary sphincters

31

What causes an increase in resistance?

Contraction of smooth muscle by sympathetic nervous system. Vasoconstriction

32

What hormone provides basal level of pressure?

Norepinephrine

33

What are platelets?

Form plug to fix damage to blood cells

34

What is hemostasis?

body's mechanism of preventing bleeding

35

What is fibrin?

protein forming mesh that holds platelet plug together

36

What is fibrinogen?

converted into fibrin by thrombin when bleeding occurs

37

When is oxygen not favored by hemoglobin?

decreased pH, increased PCO2, increased temperature

38

What is the site of exchange between blood and tissues?

capillaries

39

What causes water to flow out of capillaries?

Hydrostatic Gauge Pressure and differences in osmolarity

40

What substance freely passes through capillaries?

Salts

41

What cells are able to squeeze through capillaries?

Macrophages and neutrophils

42

What gives plasma high osmolarity?

Albumin

43

What is oncotic pressure?

Osmotic Pressure provided by plasma protein

44

Where is hydrostatic pressure the lowest?

Near the end of a capillary