Chapter 20 - Blood vessels Flashcards
1
Q
What are the three layers of the vessel wall?
A
- Tunica interna 2. Tunica media 3. Tunica externa
2
Q
What are the primary functions of blood vessels?
A
- To form a closed system of tubes 2. To transport materials throughout the body 3. They play an important role in adjusting velocity and volume of blood flow
3
Q
What do blood vessels transport throughout the body?
A
- They carry nutrients to cells 2. They carry waste away from excretions
4
Q
The circulation of blood flow
A
Heart -> Arteries -> Arterioles -> Capillaries -> Venules -> Veins -> Heart
5
Q
This is the innermost layer of a blood vessel wall and consists of three parts
A
Internal Elastic Lamina
6
Q
This is a single layer of cells in direct contact with the blood
A
Endothelium of Tunica interna
7
Q
This has: 1. Endothelium 2. Basement membrane 3. Internally elastic lamina
A
Tunica interna
8
Q
This anchors endothelium to underlying Connective tissues
A
Basement membrane of Tunica interna
9
Q
This is a thin sheet of elastic fibers that separates this layer from the Tunica media
A
Tunica interna
10
Q
This is the middle layer of blood vessel walls
A
Tunica media
11
Q
This has smooth muscles and elastic fibers
A
Tunica Media
12
Q
This wraps circularly around the vessel
A
Smooth muscles of Tunica media
13
Q
This regulates the diameter of the vessel lumen
A
Smooth muscle of the Tunica media
14
Q
This is the outermost layer of a blood vessel wall
A
Tunica externa
15
Q
This is separate from that Tunica media by the external elastic Lamina
A
Tunica externa
16
Q
This consists mainly of elastics and collagen fibers
A
Tunica externa
17
Q
This protects the vessels and anchors it to the surrounding tissue
A
Elastic and collagen fibers of Tunica externa
18
Q
This contains many nerves
A
Tunica externa
19
Q
It is supplied by its own set of tiny vessels call vasa vasorum
A
Tunica externa
20
Q
A network of small blood vessels that supply large blood vessels
A
Vasa vasorum
21
Q
This artery is the largest in diameter and is near the heart
A
Elastic arteries
22
Q
This artery has the highest proportion of elastic fibers in Tunica media
A
Elastic arteries
23
Q
This artery help propel blood onward while ventricles are relaxing
A
Elastic arteries
24
Q
What happens to the ventricles when there is a surge of blood?
A
It stretches
25
What happens to the ventricles when pressure decreases?
It recoils
26
This artery allow blood to flow smoothly and continuously even though the heart is alternately contracting and relaxing
Elastic arteries
27
This is also call conducting arteries
Elastic arteries
28
Why are you elastic arteries also call conducting arteries?
Because they conduct blood from the heart to muscular arteries
29
This artery is medium-size and distal to elastic arteries
Muscular arteries
30
The Tunica media of this artery has more smooth muscles and fewer elastic fibers than elastic arteries
Muscular arteries
31
That Tunica media of this artery walls are very thick
Muscular arteries
32
This artery is very active in vasoconstriction
Muscular arteries
33
This artery adjust bloodflow and blood pressure through vasoconstriction
Muscular arteries
34
This artery is capable of greater vasoconstriction and vasodilation
Muscular arteries
35
They are also call distributing arteries
Muscular arteries
36
Why are muscular arteries also call distributing arteries?
Because muscular arteries continue to branch and ultimately distribute blood to each of the various regions of the body
37
The union of branches of two or more artery supplying the same body region
Anastomoses
38
This can provide alternative routes for blood to reach a tissue or organ
Anastomoses
39
The alternative circulatory route of blood flow to body parts through anastomosis
Collateral circulation
40
Arteries that do not anastomosis
End arteries
41
Muscular arteries are divided into smaller arteries which divide into what?
Arterioles
42
The Tunics minimize as they near capillary beds
Arterioles
43
They are mostly muscles but have a thin Tunica interna
Arterioles
44
The most distal end of the arteriole is called what?
Metarteriole
45
This Feeds the capillary beds
Metartetioles
46
This regulates blood flow into the capillaries
Precapillary sphincter
47
This vessel regulates resistance
Arterioles
48
What increases resistance of Arterioles?
Contraction of smooth muscle
49
What can significantly affect blood pressure?
Resistance in the Arterioles
50
A microscopic vessels that connects Arterioles to venules
Capillaries
51
This function in the exchange of materials between the blood and the interstitial fluid
Capillaries
52
They are fed by metarterioles
Capillaries
53
They are found near almost every cell in the body
Capillaries
54
Their number varies with metabolic activity of tissues they serve
Capillaries
55
This constrict to restrict flow
Precapillary sphincters
56
The walls consists of a single layer of epithelium and a basement membrane
The structure of capillaries
57
The capillary bed is a network of how many capillaries that branch from a single metarteriole
10-100
58
Blood flows through all capillaries in a capillary bed or through a Center vessel call a thoroughfare Channel
The structure of capillaries
59
The distal end of the vessel and has no smooth muscles
Thoroughfare channel
60
This provides direct route for blood from an arteriole to a Venule, bypassing capillaries
Thoroughfare channel
61
The ability of a tissue to match blood flow to its metabolic needs
Autoregulations of capillaries
62
This is very important in the brain, heart and skeletal muscles
Autoregulation of capillaries
63
Vasoconstrictors cause constrictions of precapillary sphincters
Autoregulation of capillaries
64
Vasodilators release by cells causes relaxation of precapillary sphincter
Autoregulations of capillaries
65
What are the three capillary type?
1. Continuous 2. Fenestrated 3. Sinusoids
66
Endothelial cells with only small gaps bewteen cells called intercellular clefts
Continuous Capillaries
67
Endothelial cells that allow for more exchange of materials
Fenestrated Capillaries
68
Walls have very large pores that allow large molecules and even blood cells to pass through
Sinusoids Capillaries
69
What does teh capillary exchange mechanisms include?
1. Diffusion 2. Transcytosis 3. Bulk flow
70
Molecules move down their concentration gradient
Diffusion
71
Mainly important for large, lipid-insoluble molecules
Transcytosis
72
"pushes" fluid out of the blood into interstitial fluid
Capillary blood pressure
73
Helps blood retain fluids in vessels
Blood colloid osmotic pressures
74
When water is drawn into the blood because of the large number of plasma proteins
Blood colloid osmotic pressures
75
PRessure driven movement of fluid and solutes FROM blood INTO interstitial fluid
Filtration
76
Where does filtration occur?
Mostly at teh arterial end of a capillary
77
Pressures driven FROM interstitial fluid INTO blood vessels
Reabsorption
78
Where does reabsorption occur?
Mostly at the venous end of a capillary
79
What does capillaries unite to form?
Venules
80
Where do venules circulate to?
They drain into veins
81
Are thin walled and some are ver porous
Venules
82
Return blood to the heart
Veins
83
Have all 3 Tunica layers
Veins
84
Thinner than arteries
Veins
85
Many have valves to prevent back flow
Veins
86
Has a low pressure system
Veins
87
What causes varicose veins?
Leaky venous valves
88
Leaky valves allow blood to back flow and pool in the veins and fluid leaks out into surrounding tissues
Varicose veins
89
This creates pressure that distends the veins
Leaky valves that backflow and pool in the veins
90
Are most common in superficial veins of lower limbs
Vericose veins
91
What are hemorrhoids?
They are varicose veins in the anal canal
92
Where is blood mostly at?
The systemic veins and venules
93
What precent of blood is in the systemic veins and venules?
64%
94
What is another name for systemic veins and venules?
Blood reservoirs
95
Brain stem can vasoconstrict these vessels allowing greater blood flow to skeletal muscles
Blood reservoirs
96
Mechanisms that "pump" blood from lower body to heart
Venous return
97
Skeletal muscle pump
When the skeletal muscles squeeze veins as teh contract
98
Respiratory pump
during inhalation, the diaphragm moves downward increasing pressure in abdominal cavity and decreasing pressure in thoracic cavity
99
Abdominal veins are compressed and blood forced upward
Respiratory pump
100
The volume of blood that flows through any tissue in a given time period
Blood flow
101
What is the equation of blood flow?
mL/min
102
What is the Total Blood Flow?
Cardiac Output (CO) the volume of blood that circualtes through systemic (or pulmonary) blood vessels each minute
103
What is hydrostatic pressure?
Pressure exerted by blood on walls of blood vessels
104
What is systolic blood pressure?
The highest pressure attained in arteries during ventricular systole
105
What is diastolic blood pressure?
The lowest pressure during ventricular diastole
106
What is pulse pressure?
The difference between systolic and diastolic pressures
107
What is Mean arterial pressure?
The average of systolic and diastolic pressure
108
MAP stands for what?
Mean Arterial Pressure
109
Pressure exerted by blood on walls of blood vessels
hydrostatic pressure
110
The highest pressure attained in arteries during ventricular systole
systolic blood pressure
111
The lowest pressure during ventricular diastole
diastolic blood pressure
112
The difference between systolic and diastolic pressures
pulse pressure
113
The average of systolic and diastolic pressure
Mean arterial pressure (MAP)
114
What are the main factors that influence blood pressure?
1. Cardiac Output (CO) 2. Peripheral Resistance (PR) 3. Blood volume
115
What is the equation for blood prssure?
CO x PR
116
How are blood pressure varied?
Directly by CO, PR and blood volume
117
Opposition to blood flow due to friction between blood and walls of vessels
Vascular Resistances
118
Another name for Vascular resistances
Peripheral resistance (PR)
119
What happens when you increase resistance?
BP increases
120
What happens when you decrease resistance?
BP decreases
121
What 3 things does systemic vascular resistance depends on?
1. Size of Lumen 2. Blood viscosity 3. Vessel Length
122
What happens when you have thinner blood?
Less resistance
123
What happens when you have a larger lumen vessel?
Less resistance
124
What happens when the vessel length is shorter?
Less resistance
125
1 xtra lb equals how many miles of blood vessels
200 miles of blood vessels
126
