Chapter 20: Circulatory System Flashcards
(113 cards)
1
Q
diffusion
A
substances leave or enter blood according to their concentration gradient (high to low concentration)
2
Q
What diffuses from blood to interstitial fluid/in?
A
oxygen, hormones, and nutrients
3
Q
what diffuses from tissue to blood/out?
A
carbon dioxide and wastes
4
Q
the route diffusion takes depends on particle _______
A
size
5
Q
vesicular transport
A
form fluid-filled vesicles at the plasma membrane and transport substances across the cell
6
Q
endothelial cells use _____________ and ________________
A
pinocytosis and exocytosis
7
Q
bulk flow
A
fluids flow down the pressure gradient
8
Q
during bulk flow, large amounts of ________ and ____________ ________________ move
A
fluids and dissolved substances move
9
Q
bulk flow’s movement direction depends on
A
net pressure of opposing forces
10
Q
filtration
A
fluid moves out of the blood
11
Q
what is blocked during filtration
A
large solutes
12
Q
where does filtration occur
A
on arterial end of capillary
13
Q
reabsorption
A
fluid moves back into the blood
14
Q
where does reabsorption occur
A
on venous end of capillary
15
Q
hydrostatic pressure (HP)
A
force exerted by a fluid
16
Q
blood hydrostatic pressure (HPb)
A
- also called blood pressure
- force exerted per unit area by blood on vessel wall
- promotes filtration from capillary
17
Q
interstitial fluid hydrostatic pressure (HPif)
A
- force of IF on outside of blood vessel
- close to zero in most tissues
18
Q
colloid osmotic pressure (COP)
A
the “pull” on water due to the presence of proteins (colloid)
19
Q
blood colloid osmotic pressure
A
- pulling pressure
- promotes reabsorption
- draws fluid into blood due to blood proteins (albumins)
20
Q
interstitial fluid colloid osmotic pressure
A
- draws fluid into IF
- few proteins present in IF, meaning it is relatively low
21
Q
net filtration pressure (NFP)
A
the difference between net hydrostatic pressure and net colloid osmotic pressure
22
Q
NFP changes along
A
length of a capillary
23
Q
NFP is ___________ at the arterial end than at the venous end
A
higher
24
Q
equation to find NFP
A
NFP= (HPb - HPif) - (COPb - COPif)
25
lymphatic vessels look like
weak little veins
26
lymphatic system
- picks up excess fluid not reabsorbed at the venous capillary end
- filters fluid and returns it to venous circulation
27
process of "washing" blood vessels
blood plasma-> interstitial fluid -> lymph -> blood plasma again
28
local blood flow ___________ and not all capillaries are ____________ ____________
varies/ are filled simultaneously
29
blood flow must be
high enough to maintain adequate perfusion
30
local blood flow is dependent on
- degree of tissue vascularity
- myogenic response
- local regulatory factors altering blood flow
- total blood flow
31
degree of vascularization
the extent of vessels in a tissue
32
angiogenesis
formation of new vessels
- occurs over weeks to months to increase potential perfusion
33
regression
break down of unneeded blood vessels
- return to previous state of blood vessels
34
tumor angiogenesis
cancer cells require oxygen and nutrients and trigger growth of new vessels as tumor grows
35
myogenic response
smooth muscle in blood vessel wall keeps blood flow relatively constant
36
blood flow is regulated
locally
37
based on need:
- changes when metabolic activity changes
- tissue is damaged
38
vasoactive chemicals
alter blood flow
39
vasodilators
dilate arterioles and relax precapillary sphincters
40
vasodilators increase
flow into capillaries
41
vasoconstrictors
constrict arterioles and cause contraction of precapillary sphincters
42
autoregulation
the process by which a tissue regulates or controls its local blood flow as a response to its changing metabolic needs
43
when tissue activity increases, ________________ signals inadequate perfusion and act as ________________
varied stimuli/ vasodilators
44
when tissue activity increases ____________________ decline
oxygen and nutrient levels
45
when tissue activity increases __________, __________, _____, and ____, increase
carbon dioxide, lactic acid, H+, and K+
46
as perfusion __________, vessels __________ in response
increases/ constrict
47
reactive hyperemia and an example
increase in blood flow after it is temporarily disrupted
- e.g., enter a warm room after being cold
48
inflammation
damaged tissue, leukocytes, and platelets release vasoactive chemicals
49
inflammation mediators that cause arterioles to dilate
histamine and bradykinin
50
inflammation may also stimulate the release of ___________, another vasodilator
nitric oxide
51
tissue damage can also lead to release of _________________
vasoconstrictors
52
local hormones released in response to tissue damage
leukotrienes, thromboxanes, and prostaglandins
53
total blood flow
the amount of blood transported through vasculature per unit of time
54
total blood flow is equal to
cardiac output
55
total blood flow may
increase with exercise
56
mean arterial pressure (MAP)
average arterial blood pressure across entire cardiac cycle
56
regulation of total flow depends on both the ________ and __________
heart and vessels
57
how to find pulse pressure
subtract the systolic pressure from the diastolic pressure
57
MAP equation
MAP= diastolic pressure + 1/3 pulse pressure
57
MAP provides
index of perfusion
57
venous blood pressure
low and does not pulsate
58
venous return of blood to the heart depends on
pressure gradient, skeletal muscle pump, and respiratory pump
59
venous BP is ___ mm Hg in venules and almost ___ in vena cava
20/ 0
60
skeletal muscle pump
assists venous return from limbs
61
respiratory pump
assists venous return in the thorax
62
resistance
friction blood encounters; opposes blood flow (F)
63
resistance is due to
contact between blood and vessel wall
64
peripheral resistance
resistance of blood in blood vessels (as opposed to heart)
65
peripheral resistance is affected by 3 variables that oppose blood flow
viscosity, vessel length, and lumen size
66
blood viscosity
resistance of fluid to its flow
67
resistance and vessel length
longer vessels create more resistance
68
____________ occurs along length of vessel
friction
69
resistance and vessel radius
smaller radius creates more resistance
70
blood has ____________ flow
laminar
71
laminar flow
different flow rate within vessel
72
total blood flow equation
F 🐟 △P/R
blood flow porportional to pressure gradient/resistance
73
systematic blood pressure gradient =
△P (change in BP from high to low)
74
in systematic blood pressure gradient, if the gradient ____________, total blood flow __________
increases/ increases
75
blood flow is ____________________ to pressure gradient but ________________________ to resistance
directly proportional/ inversely proportional
76
resistance=
R
77
as resistance ______________, total blood flow ______________
increases/decreases
78
resistance can be increased by what 3 variables
1- INCREASING blood viscosity
2- INCREASING vessel length
or
3- DECREASING vessel lumen diameter
79
receptors collect
data
80
baroreceptors
check on BP in carotid arteries and the aorta
81
chemoreceptors
detect oxygen and carbon dioxide
82
The cardiovascular center of the medulla contains what 2 autonomic nuclei
1- cardiac center
2- vasomotor center
83
cardiac center
influences BP by influencing cardiac output
84
vasomotor center
influences BP by influencing vessel diameter
85
vessel constriction influences
resistance
86
chemoreceptor reflexes influence
BP
87
stimulation of chemoreceptors brings about _________________________ to return blood chemistry to _________
negative feedback reflexes/ normal
88
chemoreceptors responses in _________________ and _______________ systems
respiratory and cardiovascular systems
89
hypothalamus can increase __________________ and ________________-
cardiac output and resistance
90
limbic system can alter ________________ in response to emotions or memories
blood pressure
91
renin-angiotensin system
- liver is continuously releasing inactive angiotensinogen in the blood
- kidneys release renin in response to BP or sympathetic nervous system
- renin converts angiotensinogen to angiotensin I
- ACE (angiotensin-converting enzyme), which is located in the capillaries of the lungs, converts angiotensin I to angiotensin II
- angiotensin II raises BP in 3 ways
92
baroreceptors are located
in the kidneys
93
3 ways angiotensin II can regulate BP
1- acts as a powerful vasoconstrictor
2- stimulates thirst center
3- acts on kidneys to decrease urine formation
94
-ogen
inactive
95
ACE inhibitor helps
lower BP
96
angiotensin II stimulates the release of _________________ and ____________________ causing vasoconstriction
aldosterone and antidiuretic hormone
97
aldosterone
- released from adrenal cortex
- release triggered by several stimuli, including angiotensin II
- increases absorption of sodium ions and water in the kidney (decreases urine output)
98
antidiuretic hormone (ADH)
- released from posterior pituitary gland
- release triggered by nerve signals from the hypothalamus
99
ADH effects
- increases water reabsorption in kidney
- stimulates thirst center to increase fluid intake
- in large amounts, it causes vasoconstriction
100
ADH is termed a
vasopressin
101
atrial natriuretic peptide (ANP)
- decreases BP
- released from atria of heart when walls are stretched by high volume
- stimulates vasodilation
- increases urine output
- mechanisms for BP homeostasis involve CO, R, & BV
102
variables directly relate to pressure:
increasing any of them will raise BP
103
BP measured indirectly using
sphygomanometer
104
systolic pressure is the
top number
105
diastolic pressure is the
bottom number
106
hypertension
chronically elevated blood pressure
107
atherosclerosis
progressive disease of the elastic and muscular arteries
108
arteriosclerosis
hardening of the arteries
109
hypotension
chronically low blood pressure
