Flashcards in Chapter 21 Deck (52):
1
5 general classes of blood vessels
1. arteries
2. arterioles
3. capillaries
4. venules
5. veins
2
arteries
carry blood aways from heart
3
arterioles
smaller branches of arteries found in tissues
4
venules
smaller veins
5
veins
larger vessels that carry blood toward heart
6
where is all the blood located in the body?
-answer
-total blood volume in venous system
-blood is unevenly distributed among blood vessel
- ~70%
7
systemic venous system
-3 things
1. venules and medium-sized veins (25%)
2. large venous networks (liver, bone marrow, skin) (21%)
3. large veins (18%)
8
pulmonary circuit
-total percent
-3 things
-9%
-1. pulmonary arteries (3%)
2. pulmonary capillaries (2%)
3. pulmonary veins (4%)
9
Heart
-percentage of blood
-7%
10
systematic arterial system
-percent
-4 things
-13%
-1. aorta (2%)
2. elastic arteries (4%)
3. muscular arteries (5%)
4. arterioles (2%)
11
systematic capillaries
-percent
7%
12
3 types of veins
1. large vein
2. medium sized vein
3. venule
13
2 types of capillary
1. fenestrated
2. continuous
14
large vein
superior and inferior vena cava
15
venule
collect blood from capillary
16
fenestrated capillary
pores penetrate endothelium
17
continuous capillary
endothelium is complete
18
3 types of arteries
1. elastic artery
2. muscular artery
3. arterioles
19
elastic arteries
-known as
-function
-conducting arteries
-transport large volumes of blood away from heart
20
muscular artery
distribution arteries
21
capillaries
-definition
-what do they function as
-high tissue demand for O2
-low tissue demand for O2
-only blood vessels that permit exchange between blood and surrounding
-an interconnected network - capillary bed
-precapillary sphincter opens
-precapillary sphincter closes
22
precapillary sphincter opens
-what does this allow
allows more blood flow through capillary bed
23
precapillary sphincter closes
-what does this allow
less blood flow through capillary bed
24
what is at the entrance to the capillary
band of smooth muscle
25
structure of blood vessels
-3 distinct layers
1. tunica intima
2. tunica media
3. tunica externa
26
tunica intima
-layer
-type of tissue
-innermost layer
-squamous epithelium = endothelium
-layer of connective tissue (areolar and elastic)
27
tunica media
-layer
-2 features
-middle layer
-layers of smooth muscle -allows vessel diameter to change
-supplied by ANS
28
Tunica externa
-2 features
-outer most layer
-connective tissue
29
vessel: artery
-endothelium (tunica intima)
-areolar/elastic tissue (tunica intima)
-tunica media
-tunica externa
-yes
-yes
-yes (large and thick)
-yes
30
vessel: arteriole
-endothelium (tunica intima)
-areolar/elastic tissue (tunica intima)
-tunica media
-tunica externa
-yes
-yes
-yes (less elastic tissue, more smooth muscle)
-yes
31
vessel: capillary
-endothelium (tunica intima)
-areolar/elastic tissue (tunica intima)
-tunica media
-tunica externa
-yes
-no
-no
-no
-no
32
vessel: venule
-endothelium (tunica intima)
-areolar/elastic tissue (tunica intima)
-tunica media
-tunica externa
-yes
-no
-no
-yes
33
vessel: vein
-endothelium (tunica intima)
-areolar/elastic tissue (tunica intima)
-tunica media
-tunica externa
-type of vessels located in tunica media
-yes
-yes
-yes (less smooth muscle compared to arteries)
-Capacitance vessels - able to easily expand
34
special feature of veins
valves
35
valves
-function
-what are they?
-permit blood flow in only 1 direction and are required to overcome the force of gravity
-extensions of the tunica interna
36
valves closed
prevents back flow of blood
37
valves opened
contraction of skeletal muscle helps to squeeze blood toward heart
38
Blood flow
-definition
-total blood flow =
-why does blood flow
-volume of blood flowing through a vessel or group of vessels
-cardiac output
-due to pressure gradients (moves from high to low)
39
what creates the pressure in blood
the heart
40
2 factors affecting blood flow
1. F a P
2. F a 1/R
41
F a P
-definition
-ex
flow is directly proportional to the pressure gradient
- increase Pressure = increase Flow
42
F a 1/R
-definition
-ex 1
-ex 2
-flow is inversely proportional to resistance
-increase resistance = decrease flow
-decrease flow = increase resistance
43
resistance
radius of vessel and viscosity of blood
44
blood pressure
force of blood exerted against the vessel wall
45
arterial blood pressure
-definition
-how is it reported
pressure of blood in arteries
- reported as mmHg
46
venous blood pressure
-definition
-low or high pressure
-pressure within the venous system
-very low
47
measuring arterial blood pressure : heart contracts
-where is the blood ejecting
-pressure
-type of pressure
-into aorta and arteries
-pressure in arteries is increasing to 120 mmHg
-systolic pressure
48
systolic pressure
-definition
-highest or lowest pressure in aorta
pressure in arteries due to ventricular systole
-highest pressure in aorta
49
measuring arterial blood pressure: heart relaxes
-blood is ejected where
-blood flows up or down pressure gradient
-pressure
-type of pressure
-blood is not ejected into arteries
-down
-decreases to 80 mmHg
-diastolic pressure
50
diastolic pressure
-definition
-highest or lowest pressure in aorta
pressure in arteries during ventricular diastole
51
how do you measure
-what is the norm
systolic/diastolic
-120/80
52