Circulatory Flashcards
(227 cards)
1
Q
Connective tissue composed of primarily
collagenous fibers
§ Helps to anchor vessels to surrounding tissue
§ Contains small amount of elastic fibers
A
Tunica Externa (Adventitia)
Thinnest for arteries
2
Q
Normally the thickest layer ( for veins)
Collagenous fibers predominate
Some smooth muscle fibers
Nervi vasorum and vasa
vasorum present
A
Tunica Externa (Adventitia)
3
Q
- External elastic lamina (membrane - only found in arteries, not veins)
- Smooth muscle (some elastic fibers) layer
§ Regulates the diameter of the vessel lumen
§ Is innervated by sympathetic nerve fibers only (Nervi vasorum)
A
Tunica Media
4
Q
Tunica Interna ( Intima ) (3 layers)
A
- internal elastic lamina layer (arterial)
- basement membrane layer (arterial, venous)
- endothelial cell layer (arterial, venous)
5
Q
Known as “resistance vessels”
A
Arterioles
6
Q
A change in arteriole diameter causes changes to blood pressure overall
A
Check
7
Q
Vasoconstriction of arterioles causes increased/decreased systemic blood pressure
A
increased
8
Q
Tightly regulate blood flow from metarteriole into capillaries
A
Pre-capillary Sphincters
9
Q
At rest, these are usually closed in tissue not being used
A
Pre-capillary Sphincters
10
Q
Exchange of nutrients and waste products can only occur at the ____ level
A
capillary and postcapillary venule
NOT AT TISSUE LEVEL
11
Q
Capillaries near almost every cell in the body except
A
Not found in avascular tissues such as the cornea of the eye, the lens of the eye, and cartilage
These tissues undergo nutrient/waste exchange by diffusion with nearby vascular cells
12
Q
Tissues with higher ____ have more extensive capillary networks
A
metabolic demand
Muscles, brain, liver, kidneys, nervous system
13
Q
Smallest blood vessels
A
capillaries
14
Q
Blood cells are often 8µm, causing ____ through the capillaries
A
them to fold over and pass “single file”
15
Q
These form the union between arterial and venous blood
A
capillaries
16
Q
Three types of capillaries
A
continuous
fenestrated
sinusiod
17
Q
All three consist of a ____only
A
single endothelial cell layer and basement membrane
18
Q
Capilaries lack
A
Lack tunica media and tunica externa
19
Q
In most tissues at rest, only a small portion of the capillary network receives blood because the need for metabolic exchange is low
A
the need for metabolic exchange is low
20
Q
Contraction/relaxation of pre-capillary sphincters ~ 5-10 times per minute while tissue is at rest
A
vasomotion
21
Q
Regulates blood flow through capillary beds
A
vasomotion
22
Q
This tissue would become ____ without vasomotion
A
ischemic
23
Q
Vasomotion Mostly due to local chemicals released by endothelial cells in response to
A
Oxygen level
Carbon dioxide level
Lactic acid
Hydrogen levels
24
Q
majority of capillaries in body
A
continuous
25
These ___ are where exchange of smaller molecules occurs (continuous capillaries
clefts
26
Cont. cap found in
Central nervous system
Skin
Muscles
Lungs
27
Fenestrated capillaries' Endothelial cells have many fenestrations (cytoplasmic holes) allowing for _____
diffusion of larger particles
28
Fenestrated capillaries found in
Kidneys
Villi of small intestine
Choroid plexuses of ventricles of brain
Ciliary processes of the eyes
Some endocrine glands (hypothalamus, pituitary, pineal gland and thyroid)
29
Least common type of capillary
sinusoid
30
May have unusually large fenestrations
sinusoid
31
Very large intercellular clefts allowing some proteins and even some blood cells to pass through
sinusoid
32
Sinusoid found
Liver
Spleen
Bone marrow
Lymph nodes (carry lymph, not blood)
Many endocrine glands (adrenal glands, pituitary gland, thyroid gland for examples)
Yes…some tissues contain more than one type of capillary
33
Some parts of the body blood may pass from one capillary network into another capillary network
portal system
34
Portal system e.g.
hepatic portal circulation (liver)
hypophyseal portal system (pituitary)
35
Very small veins that receive blood flow directly from capillary beds
Postcapillary venules
36
Walls of the smallest venules are porous allowing phagocytic WBCs to pass through to inflamed or infected tissue
diapedesis
Postcapillary venules
37
Thin walls of both _____ are the most distensible elements of the entire vascular system
postcapillary and muscular venules
38
No more exchange at this level
Become thicker walled (50-200µm diameter) preventing metabolic exchange with interstitial fluid
muscular venules
39
Serve as reservoirs for large amounts of blood if needed
muscular venules
40
Distensible enough to adapt to variations in volume and pressure of blood passing through them
veins
41
High capacitance
Veins
42
High capacitance
capacity to distend to store high volume of blood
Distensible enough to adapt to variations in volume and pressure of blood passing through them
43
Lack internal and external elastic laminae found in arteries
veins
44
As postcapillary venules move away from capillaries, they gain _____ muscle
1-2 layers of smooth
45
Tunica Externa (adventitia)
Arteries
Thinner than the tunica media layer
Collagenous and elastic fibers present
Nervi vasorum and vasa vasorum present
46
Tunica Externa (adventitia)
Veins
Normally the thickest layer
Collagenous fibers predominate
Some smooth muscle fibers
Nervi vasorum and vasa vasorum present
47
Tunica Media consists of
External elastic lamina (membrane)
Smooth muscle (some elastic fibers) layer
48
External elastic lamina (membrane)
Only found in arteries, not veins
Has variable number of window-like openings (to facilitate diffusion)
49
Smooth muscle (some elastic fibers) layer
Regulates the diameter of the vessel lumen
Is innervated by sympathetic nerve fibers only (nervi vasorum)
Smooth muscle contracts/dilates for blood flow regulation as needed
50
Tunica Media (arteries)
Normally thickest layer
Smooth muscle cells and elastic fibers predominate
(Proportions of these vary with distance from the heart)
External elastic lamina (membrane-Boundary between tunica media and tunica externa)
51
Tunica Media (veins)
Normally thinner than tunica externa
Smooth muscle cells and collagenous fibers predominate
Has nervi vasorum and vasa vasorum in this layer as well
No external elastic lamina present
52
Thin folds of tunica interna (intima) that form cusps
vein valves
53
Vein valves from what membrane
tuninca interna (intima)
54
Vein with thin endothelial wall, no smooth muscle
The surrounding dense connective tissue replaces the tunica media and tunica externa in providing support
Vascular Sinus
coronary sinus
55
These connections are “perforating” veins
Superficial veins form small connections with these deep veins
56
Superficial veins are much larger than the deep veins
Upper Limbs
57
Deep veins are much larger than the superficial veins in
lower limbs
58
Tunica Interna (Intima) consists of
internal elastic lamina layer (arterial)
basement membrane layer (arterial, venous)
endothelial cell layer (arterial, venous)
59
Internal elastic lamina only found in
arteries
60
Basement Membrane (subendothelial layer)
Provides physical support for epithelial layer
Network of collagen fibers (tensile strength and stretching/recoil)
Anchors the endothelium to underlying tunica media
permeable
61
```
Tunica Interna (Intima)
Endothelium
```
Lining of the lumen of the vessel
Proliferate to form new cells in the repair of blood vessels or the growth of new blood vessels (angiogenesis)
Active participant in the inflammatory response
62
Endothelium produces
Von Willebrand factor (helps platelet adhesion when needed)
Tissue plasminogen activator (promotes fibrinolysis)
Thromboxane (local vasoconstrictor; type of a prostaglandin)
Nitric oxide (local vasoconstrictor)
Prostacyclin (a local vasodilator; type of a prostaglandin)
Endothelin (a local vasoconstrictor)
63
Two major types of arteries
Elastic
| Muscular
64
Elastic found ....
closer to the hearrt
withstand higher pressures
65
Elastic arteries include
```
Aorta
Pulmonary trunk/pulmonary arteries
Brachiocephalic
Subclavian
Common carotids
Common iliacs
```
66
Elastic arteries have the highest percentage of elastic fibers interspersed throughout its ____
tunica media layer
67
Once expanded, elastic artery vessel walls recoil (because of elasticity) which promotes _____
propelling blood forward in the system
68
Elastic arteries purpose
Propel blood onward while ventricles are in diastole
69
Elastic artery expansion causes a momentary storage of mechanical energy called a
pressure reservoir
70
Also known as “conducting arteries”
Elastic Arteries
Conduct blood from the heart eventually to medium sized muscular arteries
71
Blood Distribution (at rest)
Most in systemic veins
least in the heart
64% is in systemic veins and venules (blood reservoirs)
13% is in systemic arteries and arterioles
7% is in the systemic capillaries
9% is in pulmonary blood vessels
7% is in the heart
72
As systemic veins and venules hold so much, they become known as
blood reservoirs (also, capacitance vessels)
73
____ reduces volume of blood in reservoirs diverting it to where its needed
Venoconstriction
74
Substances enter and leave capillaries by three basic mechanisms:
Diffusion (think concentration gradient)
Transcytosis (think large/awkward molecule movement)
Bulk Flow (think pressure gradient)
75
Most efficient exchange mechanism
bulk flow (PRESSURE)
76
CO2 and other wastes released by body cells are in higher concentration in
interstitial fluid
77
____ are usually present in arterial blood in higher concentrations than in tissue/interstitial fluid
O2 and nutrients
78
____ is slow compared to bulk flow
DIffusion
79
____ is more delicate, more directed at movement of particular substances
diffusion
80
Certain parts of brain lack blood-brain barrier and allow capillary exchange to occur more freely
Hypothalamus, pineal gland, pituitary gland
81
Most areas of brain have ____
continuous capillaries
Very “tight” junctions
82
____ used mainly for large, lipid-insoluble molecules
transcytosis
83
Transcytosis used for
Insulin- enters bloodstream by transcytosis
Certain antibodies (also proteins) pass from maternal circulation into fetal circulation by transcytosis
84
Bulk flow Consists of two pressure-driven mechanisms
Filtration
| Reabsorption
85
Bulk is ___by which large amount of fluid moves into and out of capillaries rapidly
passive process
86
Filtration
from blood within the capillaries into interstitial fluid
87
Reabsorption
from the interstitial fluid/space into blood
88
Two pressures that promote filtration
Blood hydrostatic pressure (BHP)
| Interstitial fluid osmotic pressure (IFOP)
89
One main pressure that promotes reabsorption (normally)
Blood colloid osmotic pressure (BCOP)
| minmal influence from IFHP
90
Balance of the filtration and reabsorption pressures
Net filtration Pressure (NFP)
91
Starling’s law of the capillaries-
Volume of fluid and solutes reabsorbed is near the volume of fluid and solutes filtered
92
NFP =
(BHP + IFOP) – (BCOP + IFHP)
93
If pos. NFP
promotes filtration
94
if neg. NFP
it promotes reabsorption
95
BHP- Blood Hydrostatic Pressure
PUSH fluid/solutes out of capillaries into interstitial space
Pressure blood exerts against blood vessel walls
96
IFOP- Interstitial Fluid Osmotic Pressure
“Pulls” fluid/certain solutes out of capillaries into interstitial fluid
Normally small pressure, 1mmHg because only small amounts of protein present in interstitial fluid
97
BCOP- Blood Colloid Osmotic Pressure
“pull” fluid/certain solutes from interstitial spaces into capillaries
Usually 26mmHg
Force caused by colloidal suspension of proteins in plasma
98
IFHP- Interstitial Fluid Hydrostatic Pressure
“Pushes” fluid/certain solutes out of interstitial spaces back into capillaries
SHould be zero unless pathology
Opposing pressure to BHP
99
Arterial end of capillary
Net outward pressure of 10mmHg
| Fluid moves out of capillary and into interstitial spaces (filtration)
100
Venous end of capillary
Net inward pressure of –9mmHg
Fluid moves from interstitial fluid into capillaries (reabsorption
101
On average ~85% of fluid/solutes filtered out of capillaries (into interstitial fluid) are
reabsorbed
102
excess filtered fluid/solutes and few small plasma proteins that escape from blood into interstitial fluid enter the
lymphatic capillaries (~15%)
103
An accessory route for excess fluid and some solutes to flow from the interstitial space back into blood circulation
Lymphatic System
104
Plays large part in returning nutrients from gastrointestinal tract back into circulation
Lymphatic System
105
Almost all tissues have lymphatic drainage nearby except:
Superficial portions of the skin
The central nervous system (uses cerebrospinal fluid instead)
Endomysium of muscles
Bones
106
Thoracic duct receives
Lower portion of the body, left side of the head/neck, left arm and left side of the thorax
107
Thoracic duct empties into
junction of the left internal jugular vein and left subclavian vein
108
Right lymphatic duct recevies
Right side of the head/neck, right arm, portion of right thorax
109
Right lymphatic duct empties into
blood at the junction of the right internal jugular vein and the right subclavian vein
110
Five variables influence blood flow and pressure
Cardiac Output
Compliance
Volume of blood
Viscosity of blood
Blood vessel length and diameter
111
Lymphatic usually used for
smaller proteins that made it into interstitial space (maybe from local tissue damage) or for large particulate matter that cannot cross the capillary membranes
112
Cardiac Output
Anything that increases SV or HR will increase CO, which will then increase blood pressure and increase blood flow rate
113
Ability of any compartment to expand to accommodate increased content
Compliance
114
The greater the compliance, the more effectively it accommodates surges in blood flow without
increasing resistance or blood pressure
115
Veins are more compliant than arteries and
Can expand to hold more volume
116
When “hardening of the arteries” occurs, compliance is
reduced
117
is directly proportional to pressure and flow
Blood volume
118
Hypovolemia
Pressure decreases
| Flow rate decreases
119
Hypervolemia
Pressure increases
| Flow rate increases
120
Blood consists of four main components that affect viscosity
RBC’s (solid)
WBC’s (solid)
Platelets (solid)
Plasma (fluid)
121
Blood viscosity is ____ proportional to resistance
directly
The higher the viscosity, the higher the resistance
122
Blood viscosity is _____ proportional to flow
inversely
123
Length is directly proportional to resistance
Increased vessel length = increased resistance and therefore decreased flow rate
124
Increased diameter =
decreased resistance and therefore increased flow rate
125
Influence of lumen diameter on resistance is dramatic
If an artery or arteriole constricts to ½ its original radius, the resistance to flow increases 16x’s
If dilation to twice its normal size occurs, resistance decreases to 1/16th of its original value, therefore increasing flow by 16x’s its original rate
126
Tunica media layer of muscular arteries
contains much more muscle but less elastic(than elastic)
Makes these arteries capable of greater vasoconstriction and vasodilation
Helps to adjust rate of blood flow
127
Muscular Arteries include
Axillary arteries
Brachial arteries
Femoral arteries
Also known as “distributing arteries”
128
As diameter gets bigger, the flow rate ____
increases
129
Flow (Q) can also be related to
Cross-sectional area (A)
| Linear velocity of flow (V)
130
Cross-sectional area is ____ to velocity of flow
inversely proportional
131
Velocity of flow is slowest in
capillaries
Capillaries have the greatest aggregate cross-sectional area but the smallest diameter of the vessels
132
Velocity of flow is fastest in
large vessels
Large vessels have the smallest aggregate cross-sectional area but the largest diameter
133
Take every capillary in the body, slice them lengthwise and lay them open
TONS of surface area because there are much more capillaries than there are other vessels
(aggregate cross sectional)
134
Take every elastic artery in the body, slice them lengthwise and lay them open
Much less surface area (related to capillaries) because the quantity of elastic arteries in the body compared to the quantity of capillaries is greatly reduced
135
Cross sectional of aorta
relatively small, so highest velocity of flow
136
Capillaries (surface area)
relatively high, so low velocity of flow (See chart, slide 124)
137
Flow is generally ___
laminar
138
Greatest velocity of flow is in the ____ of the vessel
center
139
Lowest velocity is near the ____
vascular wall
140
Caused by shear stress produced as blood flows past stationary wall
Streamlining
141
Turbulent flow (usually pathological) is Characterized by irregularities in flow patterns
Whorls
Vortices
Eddies
142
Occurs mainly due to the pressure generated by left ventricular contraction
Venous return
143
Pressure difference from venules (16mmHg) to right ventricle (~0.1 mmHg) is sufficient to get blood back to right heart
pressure gradient
144
If pressure in right atria or ventricle increases, ____ decreases
venous return
145
An example: if tricuspid valve is insufficient, blood will flow back into atria as ventricular contraction occurs increasing the atrial pressure, which may be enough back-pressure to cease ___ during that cardiac cycle
venous return
146
Two other mechanisms help return blood to right side of heart
The skeletal muscle pump
| The respiratory pump
147
When you stand after being seated for a period of time, the gravitational pressure may overcome the 16mmHg that the venous system is generating to return blood to the heart
Both the skeletal and respiratory pump help to overcome this external pressure
148
When the leg muscles contract (standing on tiptoes) compresses the vein....
When this occurs, blood is pushed through the proximal valve (called milking)
At the same time, the distal valve closes when blood is pushed against it from contraction of muscle above it
149
There is higher blood pressure in the foot which pushes blood back into the vein at ____ end
distal
150
diaphragm moves downward causing a decrease in pressure in thoracic cavity, but an increase in abdominal cavity pressure
The Respiratory Pump
Inhalation
151
As a result of inhalation, ____ veins are compressed pushing greater volume of blood through thoracic cavity towards the heart
The Respiratory Pump
abdominal
152
diaphragm moves upward causing an increase in thoracic cavity pressure, but a decrease in the abdominal cavity pressure
The Respiratory Pump
Exhalation
153
As a result of exhalation, the valves close preventing ___ from thoracic veins into abdomen
The Respiratory Pump
backflow
154
____ is exerted by blood on the walls of a blood vessel
Hydrostatic pressure
155
Blood pressure (BP) is determined by
Cardiac output
Blood volume
Vascular resistance
156
highest BP in arteries during systole
Systolic BP
157
lowest BP in arteries during diastole
Diastolic BP
158
BP progressively ___ as the “distance” increases from the left ventricle (in a closed loop)
drops
159
Several interconnected negative feedback systems control blood pressure by making adjustments in
Heart rate
Stroke volume
Systemic vascular resistance
Blood volume
160
Some systems allow for rapid adjustments (increase in blood pressure when ___ changes occur)
postural (skeletal and respiartory pump)
161
Other systems act slowly to help provide ____
long term regulation
162
Cardiovascular Center located in
medulla oblongata
163
Cardiovascular center regulates/controls
regulate heart rate and stroke volume and controls neural, hormonal, and local negative feedback systems that help regulate blood pressure
164
neurons that stimulate the heart
cardio stimulatory center
165
cardio inhibitory cetner
neurons that inhibit the heart
166
Vasomotor center
Vasoconstrictor center
| Vasodilator center
167
Input to CV Center
Higher brain regions such as the cerebral cortex (influencing, not controlling), limbic system, hypothalamus
E.g., Before starting a race, HR may increase from nerve impulses conveyed from limbic system OR
If temperature rises during race, hypothalamus sends impulses to CV center to help lower temperature if possible
168
Sensory Receptor Input to CV center
proprioceptors
baroreceptor
chemoreceptors
169
monitor movement of joints and muscles, accounts for rapid rise in heart rate at beginning of exercise
Proprioceptors
170
monitor changes in pressure and stretch in vessel walls
Baroreceptors
171
monitors the concentration of various chemicals in blood
Chemoreceptors
172
Sympathetic Output
Impulses reach heart via cardiac accelerator nerves
| Increases HR and contractility
173
A reduction in the ____ of sympathetic impulses reduces vascular tone
rate
174
Continual sympathetic impulses sent to arteries and arterioles throughout body which is where ____ comes from
vascular tone
175
Parasympathetic Output
Impulses conveyed along vagal nerves to the heart
Decrease HR and contractility
176
There is NO parasympathetic control over vascular tone
!!!
177
The nervous system regulates blood pressure via negative feedback loops that occur as two types of reflexes:
Baroreceptor and chemoreceptor reflexes
178
Carotid sinus monitors
pressure (baroreceptors)
Bigger = more pressure
179
Baroreceptors are ___ sensory receptors
pressure-sensitive
180
Baroreceptors Located in
aorta, internal carotid arteries, and other large arteries in neck and chest
181
Baroreceptor Reflexes- Two most important
Carotid sinus reflex
| Aortic reflex
182
Carotid sinus reflex
Helps regulate blood pressure in the brain
183
small widening of right and left internal carotid arteries just above where they branch from the common carotid arteries
Carotid sinuses
184
Nerve impulses propagate from sinus baroreceptors over sensory axons in the glossopharyngeal nerves (CN IX) then into the CV center
glossopharyngeal nerves (CN IX)
!!!!!!!!!!
185
This regulates systemic blood pressure
Aortic Reflex
186
Nerve impulses from baroreceptors (aortic arch) reach the CV center via sensory axons of the ___
vagal nerves (CN X)
187
Baroreceptors
pressure (SINUS)
188
Drop in Blood Pressure
| THE PROCESS/Feedback loop
When this occurs, the baroreceptors are stretched less
This causes nerve impulses to be sent at a slower rate to the CV center
The CV center decreases parasympathetic stimulation through vagal nerves and increases sympathetic stimulation through the cardiac accelerator nerves
(When increased sympathetic stimulation occurs, epinephrine and norepinephrine are also stimulated to be secreted in the body)
As the heart beats faster and more forcefully, cardiac output and systemic vascular resistance increase
This increases the blood pressure to normal levels
189
Increase in Blood Pressure
| process/feedback loop
When this occurs, the baroreceptors are stretched more
This causes nerve impulses to be sent at a faster rate to the CV center
The CV center increases parasympathetic stimulation through vagal nerves and decreases sympathetic stimulation through the cardiac accelerator nerves
As the heart beats slower and less forcefully, cardiac output and systemic vascular resistance decrease
(Begins to slow rate of impulses to vasomotor neurons that cause vasoconstriction, this results in vasodilation)
This decreases the blood pressure to normal levels
190
Sensory receptors that monitor chemical composition of blood
Chemoreceptor Reflexes
191
Detect CERTAIN changes in blood concentration of O2, CO2, and H+
Chemoreceptor Reflexes
| JUST hypoxia, acidosis, hypercapnia
192
Chemoreceptor Reflexes located close to
baroreceptors
193
chemoreceptors in carotid arteries
carotid bodies
194
chemoreceptors in aortic arch
aortic bodies
195
All of the following stimulate the chemoreceptors
Hypoxia- reduced plasma O2
Acidosis- increase in H+ concentration
Hypercapnia- increase in CO2 in plasma
196
If chemoreceptors are stimulated, CV center increases sympathetic stimulation to arterioles and veins causing ____
vasoconstriction and increase in BP
197
Several hormones help to SLOWLY regulate blood pressure by
Altering cardiac output
Changing systemic vascular resistance
Adjusting total blood volume
198
Activated when blood volume/flow decreases to kidneys
Renin-angiotensin-aldosterone (RAA) system
| Increases BP by increasing water retention
199
Both increase CO (cardiac output) by increasing rate and force of contraction
Epinephrine/norepinephrine
200
Causes vasoconstriction of arterioles in skin and abdominal organs (at rest, but anxious)
Epinephrine/norepinephrine
| And causes vasodilation of arterioles in cardiac and skeletal muscle
201
Causes vasoconstriction – increases BP and promotes water retention in kidneys
ADH (released in from hypothalamus in response to dehydration or decreased blood volume)
202
Atrial natriuretic peptide/hormone (ANP/ANH)
Lowers BP by causing vasodilation and promotes loss of salt and water in urine
203
Erythropoietin (EPO)
Is released by the kidneys when blood flow/oxygen is decreased
EPO stimulates the production of erythrocytes (RBC’s) in bone marrow
EPO is also a weak vasoconstrictor
204
Ability of tissue to automatically adjust its blood flow to match the metabolic demands
Local changes occurring in capillary beds regulating vasomotion
Autoregulation
205
O2 demand increased leads to....
Vasodilators dilate the arterioles and relax precapillary sphincters allowing for more blood
206
Autoregulation also controls regional blood flow in the ____
brain
207
Blood distribution to various regions in brain changes drastically for ___
different mental and physical activity
When speaking or listening, blood is increased to these regions that control speech and auditory areas
208
Two different stimuli cause autoregulatory changes in blood flow:
Physical changes
Vasodilation and vasoconstricting chemicals
209
Warming promotes _____, cooling causes vasoconstriction
vasodilation,
210
_____ occurs in arteriole smooth muscle when stretched or relaxed
Myogenic response
211
Myogenic response: More ____ contraction when stretched more
forceful
212
Several types of cells release chemicals that indirectly alter blood-vessel diameter (Not all inclusive):
WBC’s, platelets, smooth muscle fibers, macrophages, endothelial cells
213
Vasodilating chemicals
K+, H+, lactic acid, adenosine, nitric oxide (NO), kinins, histamine
214
Vasoconstricting chemicals
Thromboxane A2, serotonin, endothelin's
215
SYSTEMIC vessels ___ to allow for more oxygenated blood flow
dilate
| Autoregulation
216
PULMONARY microvasculature ____ to push blood to areas that are more effectively/highly ventilated by “fresh air” to increase O2 rapidly
constricts
| Autoregulation
217
____ is strongest closer to the heart, becomes weaker in arterioles, and disappears altogether in capillaries
Pulse
218
Sounds heard while checking BP are called ____ sounds
Korotkoff
219
Blood pressure: Squeeze bulb until brachial artery is compressed and blood flow stops (usually ___ above normal systolic pressure for patient)
30mmHg
220
Mean arterial pressure is
the average BP in arteries
221
MAP =
Diastolic BP + (Systolic - diastolic BP)/3
222
Normal MAP
70-110
223
Heart gets bigger with exercise...
who'da thought
224
Tissue perfusion (in any person) ___ as someone transitions from rest, to exercise
increases
225
Selective ___ occurs in skeletal muscles, heart, lungs, liver, and skin
vasodilation
226
(going from rest to exercise) Resistance ____ allowing more blood to flood capillary beds in these active tissues
decreases
227
Selective ____ occurs in kidneys, digestive system, and reproductive system
vasoconstriction
This allows more blood to be shunted to more metabolically demanding locations
