Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

A&P II > Chapter 19 - The Cardiovascular System - Blood Vessels > Flashcards

Chapter 19 - The Cardiovascular System - Blood Vessels Flashcards

1
Q

Delivery system of dynamic structures that begins and ends at the heart are:

A

blood vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The different blood vessels are:

A
  1. arteries
  2. capillaries
  3. veins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the function of the arteries?

A
  1. carry blood away from the heart

2. they’re oxygenated except for pulmonary circulation and umbilical vessels of fetus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the function of the capillaries?

A
  1. contact tissue cells

2. directly serve cellular needs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the function of the veins?

A

carry blood toward the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Pumping action of the heart generates:

A

blood flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Systemic blood pressure results when:

A

blood flow is opposed by resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Systemic blood pressure is highest in:

A

the aorta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Systemic blood pressure declines:

A

throughout pathway

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

The systemic blood pressure in the right atrium is ____.

A

0 mm Hg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The steepest drop of systemic blood pressure occurs in the ____.

A

arterioles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Arterial blood pressure reflects two factors of arteries close to the heart. What are they?

A
  1. elasticity (compliance or distensibility)

2. volume of blood forced into them at any time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Blood pressure near the heart is ____.

A

pulsatile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the systolic pressure?

A

pressure exerted in the aorta during ventricular contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the average systolic pressure in a normal adult?

A

120 mm Hg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is diastolic pressure?

A

the lowest level of aortic pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is pulse pressure?

A

The difference between systolic and diastolic pressure; the throbbing of arteries measures it (pulse)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the mean arterial pressure (MAP)?

A

pressure that propels blood to tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The mean arterial pressure is calculated by:

A

diastolic pressure + 1/3 pulse pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Pulse pressure and MAP both decline when?

A

With increasing distance from the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Capillary blood pressure ranges from:

A

17 to 35 mm Hg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the desirable capillary blood pressure?

A

low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What would happen with high capillary blood pressure?

A

High BP would rupture fragile, thin-walled capillaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Why is low capillary blood pressure desirable?

A

Most walls of capillaries are very permeable, so low pressure forces filtrate into interstitial spaces.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are the characteristics of venous blood pressure?

A
  1. changes little during the cardiac cycle

2. has a small pressure gradient; about 15 mm Hg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Low venous blood pressure is due to:

A

cumulative effects of peripheral resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What happens to the energy of venous blood pressure?

A

energy is lost as heat during each circuit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the factors aiding venous return?

A
  1. muscular pump
  2. respiratory pump
  3. venoconstriction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What happens during the muscular pump?

A

skeletal muscles contract and “milk” blood toward the heart; valves prevent backflow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What happens during the respiratory pump?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What happens during venoconstriction?

A

under sympathetic control it pushes blood toward the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

The structure of blood vessels:

A
  1. lumen
  2. three wall layers in arteries and veins
  3. capillaries
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

The lumen of blood vessels is:

A

the central blood-containing space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

The three wall layers in arteries and veins are:

A
  1. tunica intima
  2. tunica media
  3. tunica externa
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Capillaries are composed of:

A

endothelium with sparse basal lamina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What are the characteristics of the tunica intima?

A
  1. the endothelium lines the lumen of all vessels
  2. the endothelium is continuous with endocardium
  3. the endothelium has a slick surface that reduces friction
  4. there is a subendothelial layer in vessels larger than 1 mm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

The subendothelial layer of the tunica intima has:

A

connective tissue basement membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What are the structural characteristics of the tunica media?

A
  1. smooth muscle and sheets of elastin

2. sympathetic vasomotor nerve fibres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

The sympathetic vasomotor nerve fibres of the tunica media do what?

A
  1. control vasoconstriction and vasodilation of vessels

2. influence blood flow and blood pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

The tunica externa is also known as:

A

tunica adventitia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What are the characteristics of the tunica externa?

A
  1. collagen fibres protect and reinforce; anchor to surrounding structures
  2. contains nerve fibres and lymphatic vessels
  3. vasa vasorum of larger vessels nourishes external layer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Blood vessels vary in:

A
  1. length
  2. diameter
  3. wall thickness
  4. tissue makeup
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

The arterial system is divided into:

A
  1. elastic arteries
  2. muscular arteries
  3. arterioles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What are the characteristics of elastic arteries?

A
  1. large thick-walled arteries with elastin in all three tunics
  2. large lumen offers low-resistance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

An example of elastic arteries is:

A

aorta and its major branches

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Are elastic arteries active or inactive during vasoconstriction?

A

inactive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Elastic arteries act as:

A

pressure reservoirs–they expand and recoil as blood is ejected from the heart; there is smooth pressure downstream

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Where are muscular arteries located?

A

distal to elastic arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Muscular arteries deliver blood to:

A

body organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What structure is different in muscular arteries?

A

thick tunica media; it has more smooth muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Are muscular arteries active or inactive during vasoconstriction?

A

active

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What are the characteristics of arterioles?

A
  1. smallest arteries
  2. lead to capillary beds
  3. control flow into capillary beds
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Arterioles control flow into capillary beds via:

A

vasodilation and vasoconstriction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What are the structural characteristics of capillaries?

A
  1. microscopic blood vessels
  2. walls of thin tunica intima
  3. have pericytes
  4. provide direct access to almost every cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

In the smallest capillaries, the walls of thin tunica intima:

A

have a single cell that forms the entire circumference

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

What do the pericytes of capillaries do?

A

help stabilise their walls and control permeability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

The diameter of capillaries allows:

A

only one single RBC to pass at a time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Where are the capillaries located?

A

in all tissues except for cartilage, epithelia, cornea, and lens of the eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Capillaries exchange what?

A
  1. gases
  2. nutrients
  3. wastes
  4. hormones

between blood and interstitial fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Venules are formed when:

A

capillary beds unite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Larger venules have:

A

one or two layers of smooth muscle cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

The smallest part of venules are:

A

postcapillary venules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Venules consist of:

A

endothelium and a few pericytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Venules are very porous; they allow for:

A

fluids and WBCs to pass into tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

Veins are formed when:

A

venules converge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

What are the characteristics of veins?

A
  1. they have thinner walls, and larger lumens compared with corresponding arteries
  2. blood pressure is lower than in arteries
  3. thin tunica media
  4. thick tunica externa of collagen fibres and elastic networks
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

Veins are also called:

A

capacitance vessels (blood reservoirs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

Why are veins called capacitance vessels?

A

they contain up to 65% of blood supply

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

The adaptations of veins ensure:

A

return of blood to the heart despite low pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

Veins ensuring that blood is returned to the heart despite low pressure are a result of:

A
  1. large-diameter lumens that offer little resistance
  2. venous valves
  3. venous sinuses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

What do venous valves do?

A

prevent backflow of blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

Venous valves are most abundant in:

A

the veins of limbs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

What are venous sinuses?

A

flattened veins with extremely thin walls

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

What are examples of venous sinuses?

A
  1. coronary sinus of the heart

2. dural sinuses of the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

What are vascular anastomoses?

A

interconnections of blood vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

Arterial anastomoses provide ____ to a given body region.

A

alternate pathways (collateral channels)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

Arterial anastomoses are common in:

A
  1. joints
  2. abdominal organs
  3. brain
  4. heart
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

There are no arterial anastomoses in:

A
  1. retina
  2. kidneys
  3. spleen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

What is an example of arteriovenous anastomoses?

A

vascular shunts of capillaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

The common anastomoses are:

A

venous anastomoses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

Tissue perfusion through body tissues is involved in:

A
  1. delivery of O2 and nutrients to, and removal of wastes from, tissue cells
  2. gas exchange (lungs)
  3. absorption of nutrients (digestive tract)
  4. urine formation (kidneys)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

Rate of blood flow through body tissues must be _____ to provide proper body function.

A

precisely right amount

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

The velocity of blood flow changes as it travels through the ______.

A

systemic circulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

Velocity of blood flow is inversely related to:

A

the total cross-sectional area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

Blood flow is fastest in:

A

the aorta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

Blood flow is slowest in:

A

capillaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

Blood flow increases in:

A

the veins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

Slow capillary blood flow allows for what?

A

adequate time for exchange between blood and tissues

89
Q

Respiratory gases and nutrients in capillaries are diffused down:

A

concentration gradients

90
Q

O2 and nutrients travel from:

A

blood to tissues

91
Q

CO2 and metabolic wastes travel from:

A

tissues to blood

92
Q

Lipid-soluble molecules diffuse:

A

directly through endothelial membranes

93
Q

Water-soluble solutes pass through:

A

clefts and fenestrations

94
Q

Larger molecules, such as proteins, are actively transported in:

A

pinocytotic vesicles or caveolae

95
Q

Fluid leaves capillaries at:

A

the arterial end

96
Q

Fluid returns to capillaries at:

A

the venous end

97
Q

Fluid movement in capillaries is important in determining:

A

relative blood volumes in blood and interstitial space

98
Q

The direction and amount of fluid flow in capillaries depends on two opposing forces. What are they?

A
  1. hydrostatic

2. colloid osmotic pressure

99
Q

What does capillary hydrostatic pressure do?

A

tends to force fluids through capillary walls

100
Q

Capillary hydrostatic pressure is greater at the _____ end of bed than at the ____ end.

A

arterial (35 mm Hg); venule (17 mm Hg)

101
Q

Capillary hydrostatic pressure is also termed:

A

HPc; capillary blood pressure

102
Q

What does capillary colloid osmotic pressure do?

A

it’s created by nondiffusible plasma proteins, which draw water toward themselves

103
Q

Capillary colloid osmotic pressure is ____ mm Hg.

A

~26

104
Q

Capillary colloid osmotic pressure is also termed:

A

OPc; oncotic pressure

105
Q

Hydrostatic-osmotic pressure interactions compose the:

A

net filtration pressure (NFP)

106
Q

NFP comprises all forces:

A

acting on capillary bed

107
Q

What is the equation for NFP?

A

NFP = HP - OP

108
Q

Net fluid of NFP flows out at:

A

arterial end

109
Q

Net fluid of NFP flows in at:

A

venous end

110
Q

Does more blood leave or return in capillaries?

A

more leaves than is returned

111
Q

Excess fluid of capillaries is:

A

returned to the blood via the lymphatic system

112
Q

The three structural types of capillaries are:

A
  1. continuous capillaries
  2. fenestrated capillaries
  3. sinusoid capillaries
113
Q

Sinusoid capillaries are also known as:

A

sinusoids

114
Q

Continuous capillaries are abundant in:

A

the skin and muscles

115
Q

Continuous capillaries are unique in:

A

the brain

116
Q

What are the characteristics of continuous capillaries in the skin and muscles?

A
  1. tight junctions connect endothelial cells

2. intercellular clefts allow passage of fluids and small solutes

117
Q

What do the continuous capillaries of the brain do?

A

their tight junctions are complete, which form the blood-brain barrier

118
Q

Some endothelial cells of fenestrated capillaries contain:

A

pores (fenestrations)

119
Q

How does the permeability of fenestrated capillaries compare to continuous capillaries?

A

they’re more permeable

120
Q

How do fenestrated capillaries function?

A

they function in absorption or filtrate formation (small, intestines, endocrine glands, and kidneys)

121
Q

Characteristics of tight junctions in sinusoid capillaries:

A
  1. fewer
  2. usually fenestrated
  3. larger intercellular clefts
  4. large lumens
122
Q

Speed of blood flow in sinusoid capillaries is:

A

sluggish–allows modification

123
Q

Sluggish blood flow in sinusoid capillaries allows for:

A

large molecules and blood cells to pass between blood and surrounding tissues

124
Q

Sinusoid capillaries are only found in:

A
  1. the liver
  2. bone marrow
  3. spleen
  4. adrenal medulla
125
Q

Sinusoid capillaries have ____ in lining.

A

macrophages (to destroy bacteria)

126
Q

Capillary beds have ____.

A

microcirculation

127
Q

Microcirculation in capillary beds allows for:

A

interwoven networks of capillaries between arterioles and venules

128
Q

Characteristics of microcirculation in capillary beds:

A
  1. terminal arteriole leads to metarteriole
  2. metarteriole is continuous with thoroughfare channel
  3. thoroughfare channel leads to postcapillary venule that drains bed
129
Q

the thoroughfare channel of capillary beds is

A

the intermediate between capillary and venule

130
Q

Capillary beds contain:

A
  1. true capillaries
  2. vascular shunt
  3. portal system
131
Q

Characteristics of true capillaries of capillary beds:

A
  1. 10 to 100 exchange vessels per capillary bed

2. they branch off metarteriole or terminal arteriole

132
Q

The vascular shunt of capillary beds directly connects:

A

terminal arteriole and postcapillary venule

133
Q

The portal system of capillary beds is where:

A

2 capillary beds are separated by vein (usually) or artery

134
Q

True capillaries normally branch from ____ and return to ____.

A

metarteriole; thoroughfare channel

135
Q

What do precapillary sphincters do?

A

they regulate blood flow into true capillaries

136
Q

By precapillary sphincters, blood may go into ___ or ____.

A

true capillaries; shunt

137
Q

Blood flow through capillary beds is regulated by:

A

chemical conditions and vasomotor nerves

138
Q

Blood flow is defined as:

A

the volume of blood flowing through vessel, organ, or entire circulation in a given period

139
Q

Blood flow is measured as:

A

ml/min

140
Q

Blood flow is equivalent to:

A

cardiac output for entire vascular system

141
Q

Blood flow is relatively constant when:

A

at rest

142
Q

Blood flow varies:

A

widely through individual organs, based on needs

143
Q

Blood pressure is defined as:

A

the force per unit area exerted on wall of blood vessel by blood

144
Q

Blood pressure is expressed in:

A

mm Hg

145
Q

Blood pressure is measured as ____ near heart:

A

systemic arterial BP in large arteries

146
Q

The pressure gradient of blood pressure provides:

A

a driving force that keeps blood moving from higher to lower pressure areas

147
Q

Resistance in blood circulation is:

A

opposition to flow

148
Q

Resistance in blood circulation in measured by:

A

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

149
Q

Resistance in blood circulation is also known as:

A

peripheral resistance

150
Q

The three important sources of resistance are:

A
  1. blood viscosity
  2. total blood vessel length
  3. blood vessel diameter
151
Q

Factors that remain relatively constant in resistance are:

A
  1. blood viscosity

2. blood vessel length

152
Q

Increased viscosity of blood leads to:

A

increased resistance

153
Q

The “stickiness” of blood in viscosity is due to:

A

formed elements and plasma proteins

154
Q

Longer blood vessel leads to ____ resistance.

A

greater

155
Q

The greatest influence on resistance is:

A

blood vessel diameter

156
Q

Frequent changes of blood vessel diameter alter:

A

peripheral resistance

157
Q

Blood vessel diameter varies inversely with:

A

fourth power of vessel radius

158
Q

If blood radius vessel is doubled, the resistance is ____ as much.

A

1/16

159
Q

Vasoconstriction of blood vessels leads to:

A

increased resistance

160
Q

Major determinants of peripheral resistance are:

A

small-diameter arterioles

161
Q

Abrupt changes in diameter or fatty plaques from atherosclerosis affect resistance how?

A

dramatically increase resistance

162
Q

Because diameter or fatty plaques are changed from atherosclerosis, how is flow changed?

A
  1. Laminar flow is disrupted and causes turbulent flow

2. Irregular fluid motion leads to increased resistance

163
Q

Maintaining blood pressure requires:

A
  1. cooperation of heart, blood vessels, and kidneys

2. supervision by brain

164
Q

The main factors influencing blood pressure are:

A
  1. cardiac output
  2. peripheral resistance
  3. blood volume
165
Q

Which factors control blood pressure?

A
  1. short-term neural and hormonal controls

2. long-term renal regulation

166
Q

How do short-term neural and hormonal controls affect blood pressure?

A

they counteract fluctuations in blood pressure by altering peripheral resistance and CO

167
Q

How does long-term renal regulation affect blood pressure?

A

it counteracts fluctuations in blood pressure by altering blood volume

168
Q

Neural controls of peripheral resistance do what?

A
  1. maintain MAP
  2. Alter blood distribution to organs
  3. Operate via reflex arcs
169
Q

Neural controls of peripheral resistance maintain MAP by:

A

altering blood vessel diameter

170
Q

If blood volume gets low, MAP is maintained by:

A

all vessels being constricted except those to heart and brain

171
Q

Neural controls of peripheral resistance alter blood distribution to organs in response to:

A

specific demands

172
Q

Neural controls operate via reflex arcs that involve:

A
  1. baroreceptors
  2. cardiovascular centre of medulla
  3. vasomotor fibres to heart and vascular smooth muscle
  4. sometimes input from chemoreceptors and higher brain centres
173
Q

Clusters of sympathetic neurons in medulla oversee:

A

changes in CO and blood vessel diameter

174
Q

The cardiovascular centre consists of:

A

cardiac centres and vasomotor centre

175
Q

The vasomotor centre sends steady impulses via _____ to blood vessels. This leads to what?

A

sympathetic efferents; moderate constriction

176
Q

The moderate constriction via the vasomotor centre to blood vessels is known as:

A

vasomotor tone

177
Q

The cardiovascular centre receives inputs from:

A
  1. baroreceptors
  2. chemoreceptors
  3. higher brain centres
178
Q

Baroreceptors are located in:

A
  1. carotid sinuses
  2. aortic arch
  3. walls of large arteries of neck and thorax
179
Q

Increased blood pressure stimulates baroreceptors to:

A

increase input to vasomotor centre

180
Q

After increased blood pressure stimulates baroreceptors to increase input to vasomotor centre, what happens?

A
  1. vasomotor and cardioacceleratory centres are inhibited, causing arteriole dilation and venodilation
  2. cardioinhibitory centre is stimulated
  3. —> decreased blood pressure
181
Q

Decrease in blood pressure is due to:

A
  1. arteriolar vasodilation
  2. venodilation
  3. decreased cardiac output
182
Q

If MAP is low, what happens?

A
  1. reflex vasoconstriction
  2. —> increased CO
  3. —> increased blood pressure
183
Q

Example of MAP going from low back to increase is:

A

Upon standing baroreceptors of the carotid sinus reflex protect blood to brain; in systemic circuit as whole aortic reflex maintains blood pressure

184
Q

Baroreceptors are ineffective if:

A

altered blood pressure is sustained

185
Q

Chemoreceptors in aortic arch and large arteries of neck detect:

A

increase in CO2, or drop in pH or O2

186
Q

Chemoreceptors cause increase in blood pressure by:

A
  1. signaling cardioaccelatory centre —> increased CO

2. signaling vasomotor centre —> increased vasoconstriction

187
Q

Hypothalamus and cerebral cortex can modify arterial pressure via:

A

relays to medulla

188
Q

What is the function of the hypothalamus?

A
  1. increases blood pressure during stress

2. mediates redistribution of blood flow during exercise and changes in body temperature

189
Q

Hormonal controls are regulated short-term via:

A

changes in peripheral resistance

190
Q

Hormonal controls are regulated long-term via:

A

changes in blood volume

191
Q

When hormonal controls cause increased blood pressure, what happens?

A
  1. epinephrine and norepinephrine from the adrenal gland lead to increased CO and vasoconstriction
  2. angiotensin II stimulates vasoconstriction
  3. high ADH levels cause vasoconstriction
192
Q

When hormonal controls cause lowered blood pressure, what happens?

A

Atrial natriuretic peptide causes decreased blood volume by antagonising aldosterone

193
Q

Long-term mechanisms control BP by:

A

altering blood volume via kidneys

194
Q

Kidneys regulate arterial blood pressure by:

A
  1. direct renal mechanism

2. indirect renal (renin-angiotensin-aldosterone) mechanism

195
Q

In long-term renal regulation, baroreceptors are ineffective because:

A

baroreceptors quickly adapt to chronic high or low BP

196
Q

What is the function of direct renal mechanism?

A

alters blood volume independently of hormones

197
Q

When BP or blood volume is increased, direct renal mechanism causes:

A

elimination of more urine, thus reducing BP

198
Q

When BP or blood volume is decreased, direct renal mechanism causes:

A

kidneys to conserve water, and BP rises

199
Q

The indirect mechanism (renin-angiotensin-aldosterone mechanism) causes:

A
  1. lowered arterial blood pressure which leads to release of renin
  2. renin catalyses conversion of angiotensinogen from liver to angiotensin I
  3. angiotensin converting enzyme, especially from lungs, converts angiotensin I to angiotensin II
200
Q

The functions of angiotensin II are:

A
  1. increases blood volume

2. causes vasoconstriction directly increasing blood pressure

201
Q

Angiotensin II increases blood volume by:

A
  1. stimulating aldosterone secretion
  2. causing ADH release
  3. triggering hypothalamic thirst centre
202
Q

Blood flow to each tissue is adjusted automatically according to:

A

the relative varying of its requirements

203
Q

Autoregulation is controlled intrinsically by:

A

modifying the diameter of local arterioles feeding capillaries

204
Q

Diameter modification of local arterioles is independent of ____, which is controlled as needed to maintain constant pressure.

A

MAP

205
Q

Organs regulate their own blood flow by:

A

varying resistance of their own arterioles

206
Q

There are two types of autoregulation. What are they?

A
  1. metabolic controls

2. myogenic controls

207
Q

Both types of autoregulation determine:

A

final autoregulatory response

208
Q

In metabolic controls, vasodilation of arterioles and relaxation of precapillary sphincters occurs in response to:

A
  1. declining tissue O2

2. substances from metabolically active tissues (H+, K+, adenosine, and prostaglandins) and inflammatory chemicals

209
Q

The effects of vasodilation of arterioles and relaxation of precapillary sphincters are:

A
  1. relaxation of vascular smooth muscle

2. release of NO (powerful vasodilator) by endothelial cells

210
Q

In metabolic controls, the endothelium releases:

A

endothelins

211
Q

What are endothelins?

A

potent vasoconstrictors

212
Q

In blood flow, ___ and ___ are balanced, unless blood flow is inadequate, then ___ wins.

A

NO; endothelins; NO

213
Q

Inflammatory chemicals cause ____.

A

vasodilation

214
Q

What do myogenic controls do?

A

They keep tissue perfusion constant despite most fluctuations in systemic pressure.

215
Q

What are the characteristics of vascular smooth muscle response to stretch in myogenic controls?

A
  1. Passive stretch promotes increased tone and vasoconstriction
  2. Reduced stretch promotes vasodilation and increases blood flow to the tissue
216
Q

Passive stretch is:

A

increased intravascular pressure

217
Q

Long-term autoregulation occurs when:

A

short-term autoregulation can not meet tissue nutrient requirements

218
Q

One factor of long-term autoregulation is:

A

angiogenesis

219
Q

What are the characteristics of angiogenesis?

A
  1. number of vessels to region increases and existing vessels enlarge
  2. it is common in heart when coronary vessel is occluded, or throughout body in people in high-altitude areas

A&P II (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions