Chp 19 PP Flashcards
1
Q
What Structure/function relationships change as one moves through the cardiovascular tree
A
vessels
2
Q
Vessels Tunic thickness and composition of the three layers are
A
variable
3
Q
capillary beds flow is regulated by
A
smooth muscle valves
4
Q
allows flow through capillary bed w/out flow through caps
A
Metarterioles
5
Q
are found from arterioles to venules through capillary
A
Metarterioles
6
Q
pre-capillary sphincter
A
- True capillaries
- ring of smooth muscle
- open/close to control flow
- regulated by chemicals
7
Q
True capillaries
have intermittent vasomotion. How often do they open
A
, open for flow 5-10 times each minute
8
Q
Allow exchange of nutrients and wastes between the blood and the tissue cells
A
Capillaries
9
Q
Capillary structure
A
– simple squamous epithelium
- basal lamina - connective tissue
- endothelial cells
10
Q
3 types of capillaries
A
continuous, fenestrated, sinusoidal
11
Q
Vascular Anastomoses that provides collateral supply to some organs and tissues, e.g., skeletal muscles
A
Arterial Anastomoses
12
Q
Vascular Anastomoses are
A
- Arterial Anastomoses
- Arteriovenous Anastomoses
- Venous Anastomoses
13
Q
Vascular Anastomoses that have thoroughfare channels
A
Arteriovenous Anastomoses
14
Q
Vascular Anastomoses that are most common, e.g., deep and superficial veins in limbs and head
A
Venous Anastomoses
15
Q
At rest how much of blood volume is located in veins and venules
A
60%
16
Q
at rest serves as reservoirs for blood
A
venous system
17
Q
what veins in particular serve as reservoirs for blood
A
veins of the abdominal organs and the skin
18
Q
how does ANS regulate volume distribution
A
- vasoconstriction
- vasodilation
- diverts blood to areas with increased metabolic needs
19
Q
what organ of the body holds 1 liter of blood
A
spleen
20
Q
Flow =
A
ΔP/R
21
Q
MAP =
A
mean arterial pressure
22
Q
CO =
A
MAP/R
23
Q
when you go from higher pressure to lower pressure you do what to resistance
A
decrease resistance
24
Q
pressure of the blood on the vessel wall is
A
blood pressure
25
measure the pressure of a volume in a space
| is
blood pressure
26
norm systole/diastole is
120/80 (mm Hg)
27
what is BP at the Right atrium
0.0 mm Hg
28
opposes blood flow because of the friction produced by the vessel walls is
resistance
29
Factors that affect resistance (R)
1) viscosity
2) vessel length
3) vessel width
30
if viscosity increases what happens to resistance
resistance increases
31
"thickness” of the blood is
viscosity
32
what can cause viscosity
e.g., dehydration, elevated plasma proteins, polycythemia (RBCs), leukemias (WBCs)
33
resistance is what to viscosity
proportional
34
resistance is what to vessel length
proportional
35
what does obesity do to the route lengths within connective tissue
increases
36
resistance is what to vessel width
inversely proportional
37
decrease the radius by 1/2 and R increases by
16x
38
most important in vessels that can change their
size actively
39
changes in diameter affect
flow
40
blood cells dragging against the wall is called
vessel wall drag
41
layers of flow is called
laminar flow
42
if vessel length increases resistance
increases
43
if vessel width decreases resistance
increases
44
Systemic Vascular Resistance (SVR) =
Total Peripheral Resistance (TPR)
45
all vascular resistance is offered by the
systemic vessels
46
resistance is highest in
arterioles
47
largest pressure drop is in the
arterioles
48
Relationship of the radius to resistance in the arterioles is due to
smooth muscle contraction/relaxation
49
What does the Windkessel effect have on pulse pressure?
- Decreases pulse pressure
50
What is the effect of hardening of the arteries on pulse pressure?
Increases pulse pressure
51
Pulse pressure =
systolic (minus) diastolic
52
Arterial Blood Pressure
Pulsatile in arteries due to the pumping of the heart
| Systolic/diastolic values
53
Capillaries have what kind of Blood Pressure high or low
relatively low blood pressure
54
low pressure is good design for capillaries because:
capillaries are fragile - high pressure would tears them
capillaries are very permeable - high pressure forces a lot of fluid out
55
the volume of blood flowing back to heart from systemic veins is called
Venous return
56
venous return depends on
pressure difference from beginning of venules (16 mmHg) to heart (0 mmHg)
57
any change in right atrial (RA) pressure changes
venous return
58
what act as assistance for venous return
- skeletal muscles act as pumps
| - respiratory pump
59
how does the respiratory pump assist venous return
- inhaling causes a lowered pressure in the thoracic cavity
- primarily to pull air into the lungs
- helps to draw blood into thorax via pulmonary circulation
60
how does the skeletal muscle act as a pump for venous return
-contracting muscles squeeze veins
-force blood back to the heart
valves prevent back flow
61
Velocity of blood flow - inversely proportional to
the total cross sectional area (CSA) of vessels
62
inversely proportional to the total cross sectional area (CSA) of vessels
Velocity of blood flow
63
what has
- total CSA (cross sectional area) = 3-5 cm2
- velocity = 40 cm/sec
Aorta
64
what has
- total CSA = 4500-6000 cm2
- velocity = 0.1 cm/sec
Capillaries
65
what has
- total CSA = 14 cm2
- velocity = 5-20 cm/sec
Vena Cava
66
site of exchange between blood and tissues
Capillary Function
67
delivery of nutrients and removal of wastes
Capillary Function
68
slow flow allows time for molecules to diffuse
Capillary Function
69
Mechanisms of nutrient exchange
| in capillaries
diffusion - O2, CO2, glucose, AA's, hormones, electrolytes -- diffuse down [ ] gradients
lipid soluble molecules can pass through cell membrane easily
water soluble molecules generally require transport mechanisms to enter/exit cells
70
fluid movement in capillaries
- Fluid diffuses out and is reabsorbed across the capillary walls
- Starling’s law of the capillaries
71
Forces driving the movement of fluid
| in capillaries
Hydrostatic pressure capillary (HPc)
Hydrostatic pressure interstitial fluid (HPif)
Osmotic pressure capillary (OPc)
Osmotic pressure interstitial fluid (OPif)
72
is the net effect of all four forces at any point along the capillary
Net filtration pressure (NFP)
73
On average, how much fluid entering the tissues on the arteriole side is reabsorbed on venous end
85%
74
neural control of the cardiac centers comes from the
medulla
75
has a medullary area dedicated to control of blood vessels
Vasomotor center
76
sends sympathetic output to blood vessels
Vasomotor center
77
receives sensory input from different sources
Vasomotor center
78
what different sources does the vasomotor center receive sensory input from
baroreceptors (blood pressure)
chemoreceptors (O2, CO2, H+, HCO3-)
79
- normal amount of vasoconstriction or vasodilation is called
Vasomotor tone
80
Vasoconstricts or vasodilates as needed through sympathetic output to blood vessels
Vasomotor center
81
ANS can vary the vasomotor tone which
varies the delivery of blood to particular regional capillary beds
82
what short term mechanism for maintaining blood pressure are located at carotid sinuses and aortic arch
Baroreceptor
83
do baroreceptors monitor blood pressure
yes
84
regulates the activity of the sympathetic nervous system (vascular tone)
and help maintaining blood pressure short term
baroreceptors
85
Carotid bodies, aortic bodies
Monitor changes in indicator chemicals (O2, CO2, H+, HCO3-)
Chemoreceptor initiated reflexes
86
increased CO2, increased H+, decreased O2 (stresses) result in
increased sympathetic activity and increased blood pressure
87
what are the higher brain centers (areas above medulla) - that influence short term mechanism for maintaining blood pressure
cortex and hypothalamus
88
not involved in minute-to-minute regulation of short term blood pressure regulation
cortex and hypothalamus
89
when do the cortex and hypothalamus influence the vasomotor center
temperature changes
stressful emotional situations
90
What are the short term chemicals that influence blood pressure
renin
angiotensin
aldosterone
91
what does Renin/ACE do to influence blood pressure
enzymes from kidney/lung
catalyze formation of Angiotensin I/II
92
what does Angiotensin II do to influence blood pressure
vasoconstrictor
stimulates Antidiuretic Hormone ADH, thirst
stimulates aldosterone release for Na+ & H2O reabsorption
93
releases epinephrine and norepinephrine in coordination with activity from the Sympathetic Division of the ANS
Adrenal medulla
94
diverts blood from the skin and abdominal organs to the skeletal muscles
Adrenal medulla
95
increases heart rate, stroke volume and, therefore, cardiac output & blood pressure
Adrenal medulla
96
also stimulates vasoconstriction at high levels
ADH
97
targets kidneys to retain water
ADH
98
(ADH action is inhibited by
alcohol
99
has osmoreceptors in hypothalamus trigger release from the neurohypophysis
Antidiuretic Hormone (ADH) or Vasopressin
100
released from atrial cells in response to increased blood vol & increased BP
Atrial Natriuretic Peptide (ANP)
101
stimulates vasodilation, increases Na+ and water loss, antagonizes Aldosterone, inhibits thirst
Atrial Natriuretic Peptide (ANP)
102
controls blood volume
through nervous control - ANS and
hormones
Renal mechanism
103
what mechanism regulates in the short term by adjusting blood pressure and adjusting blood flow to different capillary beds
regulation in the long term by adjusting blood volume
Renal mechanism
104
target the kidneys
| increased BP, increases urine flow to decrease blood pressure is done by what mechanism
Renal mechanism
105
decreases blood pressure, decreases urine flow to increase blood pressure is done by what mechanism
Renal mechanism
106
short term mechanisms to maintain blood pressure are
Neural Control - Cardiac Centers in medulla (Vasomotor center)
Baroreceptor
Chemoreceptor
Cortex and hypothalamus
Chemicals
Renin - Angiotensin - Aldosterone
Adrenal medulla
Antidiuretic Hormone (ADH) or Vasopressin
Atrial Natriuretic Peptide (ANP)
107
Maintaining Blood Pressure: Long Term Regulation is done by
Renal mechanism
108
what is local automatic adjustment of blood flow to match specific local tissue metabolic needs called
Autoregulation (local control)
109
In Autoregulation Warming does what to control blood flow
increases vasodilation
110
In Autoregulation Cooling does what to control blood flow
increases vasoconstriction
111
In Autoregulation Chemical changes in local tissues generate
metabolic byproducts
| vasodilators or vasoconstrictors
112
in myogenic control smooth muscle controls what
resistance
113
increased stretching does what to contraction
increases contraction
114
decreasing stretching does what to contracting
decreases contraction
115
what has fine tuned control with wide variation in rate of blood flow
skeletal muscle
116
what organ in the body has minimal variation in rate of blood flow
and minimal nutrient storage, so adequate flow must be maintained!
brain
117
how is skeletal muscle influenced by the brain when involved with blood flow
brain directs the sympathetic division for NE release in response to the degree of muscular activity
α receptors - vasoconstriction
β receptors - vasodilation
118
skeletal muscles metabolic regulation in tissue affect O2 how
low O2 causes vasodilation, increasing flow
high O2 cause vasoconstriction, decreasing flow
119
three ways skin affects blood flow
adjusting rate of flow aids in temperature regulation
controls skin’s capacity as a blood reservoir
sympathetic and local metabolic regulation
120
what is flow regulated by in the lungs
O2
121
high o2 in the lungs does what to blood flow
high O2 causes vasodilation to increase flow – opposite of muscle
122
low O2 in the lungs does what to blood flow
low O2 causes vasoconstriction to decrease flow – opposite of muscle
123
how does the heart regulate blood flow
through sympathetic and local metabolic regulation
124
what kind of flow does the heart have depending on metabolic/pumping activity
variable
125
a portal system that transfers venous blood from one capillary bed to another capillary bed before the blood is returned to the heart
Hepatic Portal System
126
collects venous blood from five abdominal organs and routes the blood to the liver for specific processing of transported molecules
Hepatic Portal System
127
Where does HPS collect venous blood from five abdominal organs
- stomach: toxins (ethanol)
- small intestine: nutrients, toxins
- large intestine: nutrients, toxins
- pancreas: insulin, glucagon
- spleen: RBC breakdown products
128
bring oxygen and nutrients from the placenta to the liver and then to the heart of the fetus
Umbilical veins
129
in what circulation does the ductus venosus bypasses liver
Fetal Circulation
130
Fetal Circulation
3 Right > Left shunts
because oxygenated blood is derived from the placenta
- ductus arterious -> ligametum arteriosum
- foramen ovale -> fossa ovalis
- interventricular shunt -> no remnant
131
where is oxygenated blood is derived from in fetal circulation
the placenta
132
sudden dramatic loss in blood pressureor sudden decrease in circulatory flow is called
Circulatory Shock
133
Acute hemorrhage (or other sudden fluid loss as from vomiting or diarrhea) is called
Hypovolemic Shock
134
Loss of vasomotor tone as from anaphylaxis, neural malfunction, or poisons (septicemia) is called
Vascular Shock
135
Loss of cardiac output due to heart failure
| is called
Cardiogenic Shock
