CASE 3 Flashcards

1
Q

Blood vessels

A

three major types

  1. arteries
  2. capillaries
  3. veins
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2
Q

Arterioles

A

smallest branch of arteries, which feed into the capillary beds of body organs and tissues

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3
Q

venules

A

blood drains from the capillaries into the venules, smallest veins

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4
Q

wall has three layers (tunics)

A
  1. tunica intima
  2. tunica media
  3. tunica externa
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5
Q

the vessel lumen

A

central blood-containing space

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6
Q

tunica intima

A
  • closest to lumen
  • contains endothelium
  • minimizes friction as blood moves through the lumen
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7
Q

tunica media

A
  • middle tunic
  • mostly smooth muscle and sheets of elastin
  • can cause vasoconstriction of vasodilation, maintain blood pressure and circulation
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8
Q

tunica externa

A
  • loosely woven collagen fibers, protect and strengthen and anchor it to surrounding structures
  • contains nerve fibers, lymphatic vessels (and elastic fibers in bigger vessels)
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9
Q

vasa vasorum

A
  • tunica externa of bigger vessels contain the vasa vasorum
  • system of tiny blood vessels
  • nourish the tunica externa
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10
Q

Three types of arteries

A
  1. Elastic arteries
  2. Muscular arteries
  3. Arterioles
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11
Q

Elastic arteries

A
  • thick-walled near the heart
  • also called conducting arteries
  • inactive in vasoconstriction
  • expand and recoil as the heart ejects blood
  • blood flows continuously
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12
Q

muscular arteries

A
  • elastic arteries turn into muscular arteries
  • deliver blood to specific organs, also called distributing arteries
  • thickest tunica media
  • active in vasoconstriction and less capable of stretching
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13
Q

arterioles

A
  • very small ones contain one layer of smooth muscle cells
  • constrict: tissues served are largely bypassed
  • dilate: blood flow into the local capillaries increases dramatically
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14
Q

Three types of capillaries

A
  1. continuous capillaries
  2. fenestrated capillaries
  3. sinusoid capillaries
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15
Q

Capillaries

A
  • smallest blood vessels

- thin layer of tunica intima

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16
Q

pericytes

A
  • smooth muscle- like cells that stabilize the capillary wall and help control capillary permeability
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17
Q

continuous capillaries

A
  • abundant in skin and muscle
  • their endothelial cells are joined by tight junctions
  • gaps of unjoined membrane: intercellular clefts, allow limited passage of fluids and small solutes
18
Q

fenestrated capillaries

A
  • endothelial cells are riddles with oval pores, fenestrations
  • more permeable to fluids and small solutes
  • they are found wherever active capillary absorption on filtration occurs
19
Q

sinusoid capillaries

A
  • most leaky capillaries
  • found in liver, bone marrow, spleen and adrenal medulla
  • fewer tight junctions, larger intercellular clefts
  • allow blood cells to go out of the membrane
20
Q

capillary beds

A

capillaries work in networks called capillary beds.

  • consist of two types of vessels
    1. vascular shunt
    2. true capillaries
21
Q

microcirculation

A

flow of blood from arteriole to venule, through capillary beds

22
Q

vascular shunt

A

directly connects arteriole and venule at opposite ends of the bed

a. metarteriole: from terminal arteriole to middle of capillary bed
b. thoroughfare channel: from the middle of the capillary bed to the postcapillary venule

23
Q

true capillaries

A
  • exchange vessels
  • branch of the metarteriole and return to the thoroughfare channel.
  • precapillary sphincter, a cuff of smooth muscle fibers, acts as a valve to regulate blood flow into the capillary
24
Q

Venous system

A
  • carry blood from capillary beds to heart

- diameter increases and walls thicken along the way

25
Q

Venules

A
  • postcapillary venules consist of endothelium around which pericytes gather.
  • PC venules are porous; fluid and leukocytes can move easily
  • larger venules have one or two layers of smooth muscle cells and a thin tunica externa as well
26
Q

Veins

A
  • venules join to form veins
  • have 3 distinct tunics
  • tunica media has little smooth muscle and elastin
  • tunica externa, has collagen fibers and elastin networks.
  • hold up to 65% of blood supply at any time.
  • blood pressure is low to ensure that blood enters the heart at the same rate it was pumped out
27
Q

venous valves

A
  • formed from folds of tunica intima

- prevent blood from flowing backwards

28
Q

venous sinuses

A
  • flattened veins with extremely thin walls composed of only endothelium
29
Q

vascular anastomoses

A
  • special interconnections
  • arteries supplying the same territory merge forming arterial anastomoses.
  • collateral channels for blood to reach a given body region that can be used when one branch is cut or blocked.
30
Q

Blood distribution

A
  • nervous system can alter blood flow to organs

- varies according to metabolic needs of organs

31
Q

Flow through individual arterioles

A

depends on their resistance and pressure difference. The higher the resistance in arteriole, the lower the blood flow.
- The higher the difference in pressure, the higher the fluid flow
- The lower the resistance, the higher the fluid flow
this is ohm’s law

32
Q

cardiovascular control center

A
  • The CNS coordinates the reflex control of blood pressure and distribution of blood to tissues, regulated by medulla oblongata
  • ensure sufficient blood flow to the brain and heart by maintaining arterial pressure
33
Q

Cardiovascular function is regulated by

A
  • baroreceptors: maintain arterial blood pressure

- chemoreceptors : increase cardiac output and breathing rate

34
Q

exercise on pressure volume loop

A
  • small increase in end-diastolic volume because increased venous return to the heart
  • decrease end-systolic volume, because of sympathetic activation of the heart which increases ventricular contration
35
Q

Pulse pressure

A

difference between diastolic and systolic pressure

36
Q

mean arterial pressure (MAP)

A

pressure that propels blood to the tissues

37
Q

Three adaptations for venous pressure

A
  1. muscular pump
  2. respiratory pump
  3. sympathetic venoconstriction
38
Q

muscular pump

A
  • skeletal muscle, during movement, pushes blood in the desired direction
39
Q

respiratory pump

A
  • moves blood towards heart as pressure changes in ventral body cavity during breathing
40
Q

sympathetic venoconstriction

A
  • reduces the volume of blood in veins
41
Q

Short term regulation blood pressure

A

by nervous system and bloodborne hormones alter by changing peripheral resistance and cardiac output

42
Q

long term regulation blood pressure

A

alters blood volume via the kidneys