Human Anatomy and Physiology: Chapter 19 - The cardiovascular system - Blood vessels Flashcards


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1

3 major types of blood vessels are

  • arteries
  • capillaries
  • veins
2

Arterioles

small artery ; which feeds into the capillary beds of body organs and tissue

3

What are Venules

the smallest veins

4

carry oxygen-poor blood to the lungs and away from the heart

Arteries

5

carry oxygen -rich blood from the lungs toward the heart

Veins

6

of all the blood vessels, which have the intimate contact with tissue cells and directly serve cellular needs

capillaries

7

What are the 3 structural types of Capillaries

  • continuous
  • fenestrated
  • sinusoid
8

Capillaries

(very few gaps) Least leaky found in skin and muscle

Continuous

Capillaries

9

Capillaries

(Gaps/Pores) found in kidney / small intestine

Fenestrated

Capillaries

10

Capillaries

(Swiss Cheese - Immune cells moving in / out ) Found in the liver, bone marrow, spleen, and is the leakiest.

Sinusoid

Capillaries

11

This tunic is in intimate contact with the blood in the lumen, contains the endothelium, continuous w. endoCARDIAL lining of heart, slick surface that minimizes friction as blood moves through the lumen.

Tunica Intima

12
  • Bulkiest layer in the arteries
  • maintain blood pressure and circulation
  • most circularly arranged smooth muscle cells and sheets of elastin, regulated by sympathetic vasomotor nerve fibers of the autonomic nervous system

Tunica Media

13
  • tunica adventitia or outermost layer of blood vessel wall
  • composed of collagen fibers that protect and reinforce the vessel
  • contains system of tiny blood vessels VASA VASORUM

Tunica Externa

14

Shortcut bypass capillaries

Vascular Anastomoses

15

provide alternate pathways (collateral Channels) to given body region.

Common at Joints, abdominal organs, brain & heart.

NONE in retina, kidneys, spleen

arterial anastomosis

16

Volume of blood flowing through vessel, organ, or entire circulation in given period.

Measured in ML/MIN

Blood Flow

17

–Force per unit area exerted on wall of blood vessel by blood

  • Expressed in mm Hg
  • Measured as systemic arterial BP in large arteries near heart

–Pressure g radient provides driving force that keeps blood moving from higher to lower pressure areas

Blood pressure

18
  • (peripheral resistance)
  • Friction

–Opposition to flow

–Measure of amount of friction blood encounters with vessel walls, generally in peripheral (systemic) circulation

Resistance

19

mm HG

millimeter of Mercury

20

3 important sources of resistance

  • –Blood viscosity
  • –Total blood vessel length
  • –Blood vessel diameter
21
  • The "stickiness" of blood due to formed elements and plasma proteins
  • Increased viscosity = increased resistance

Blood viscosity

22

Longer vessel = greater resistance encountered

Blood vessel length

23

Greatest influence on resistance

Blood vessel diameter

24

increased resistance

Lumen diameter decreases as the smooth muscle contracts

Vasoconstriction

25
  • pressure exerted in aorta during ventricular contraction

–Averages 120 mm Hg in normal adult

Systolic pressure

26
  • lowest level of aortic pressure

Diastolic pressure

27
  • difference between systolic and diastolic pressure

–Throbbing of arteries (pulse)

Pulse pressure

28
  • pressure that propels blood to tissues
  • MAP = diastolic pressure + 1/3 pulse pressure
  • Pulse pressure and MAP both decline with increasing distance from heart

Ex. BP = 120/80; MAP = 93 mm Hg

Mean arterial pressure

(MAP)

29

contraction of skeletal muscles "milks" blood toward heart; valves prevent backflow

Muscular pump

30

pressure changes during breathing move blood toward heart by squeezing abdominal veins as thoracic veins expand

Respiratory pump:

31

under sympathetic control pushes blood toward heart

Venoconstriction

32

Maintaining blood pressure requires

Heart, blood vessels and kidneys

supervision of brain.

Brain lets kidneys control BP

Brain can take over to regulate BP

33

Main factors influencing blood pressure

  • Cardiac output (CO)
    how much blood heart is moving
  • Peripheral resistance (PR)
    work harder to generate more pressure
  • Blood volume
34

results from large-scale blood loss

Hypovolemic shock

35

results from extreme vasodilation and decreased peripheral resistance

Vascular shock

36

results when an inefficient heart cannot sustain adequate circulation

Cardiogenic shock

37

2 main circulatory Pathways

  • Pulmonary Circulation
  • Systemic Circulation
38

short loop that runs from heart to lungs and back to heart

Pulmonary circulation

39

long loop to all parts of body and back to heart

Systemic circulation

40

protect blood to brain; in systemic circuit as whole

carotid sinus reflex

41

maintains blood pressure

aortic reflex

42

Short-term neural and hormonal controls

Counteract fluctuations in blood pressure by altering peripheral resistance and CO

43

Long-term renal regulation

Counteracts fluctuations in blood pressure by altering blood volume