Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
208 Cards in this Set
- Front
- Back
|
Most capillaries are ___ in diameter and branch __ change in diameter
|
7-9mm
without |
|
|
RBC flow___through most capillaries, but some may ___
|
single file
fold |
|
|
Condition where RBC become rigid and can't fold
|
Sickle Cell
|
|
|
Capillary walls consits of ____ resting on ___
|
endothelial cells, basement membrane
|
|
|
Basement membrane is a___
|
loose layer of connective tissue(adventitia)
|
|
|
Types of pericapillary cells(3)
|
Fibroblasts
Macrophages Undifferentiated Smooth Muscle Cells |
|
|
Pericapillary cells are distributed between
|
Endothelial cells and adventitia
|
|
|
Capillaries major site of
|
metabolic exchange
|
|
|
3 Types of Capillaries
|
Continuous
Fenestrated Sinusoidal |
|
|
Continuous Capillaries have ___ between endothelial cells and are __permeable to large molecules.
Located in |
No gaps
Less permeable Nervous system, muscle |
|
|
Fenestrated Capillaries are found in____
____permeability ___is absent and membrane consists of__ |
intestinal villi, ciliary process of eye, choroid plexus of CNS, glomeruli of kidney
High permeability Cytoplasm absent Membrane consists of thin porous diaphragm |
|
|
Sinusoidal capillaries are ___than continuous or fenestrated.
___ is less prominent Occur in_ |
Larger in diameter
Basement membrane less prominent Occur in endocrine glands |
|
|
Sinusoids are ____
Basement membrane is ___ Located in___ |
Large diameter sinusoidal capillaries
BM sparse and often missing to allow large molecules to pass Found in liver and bone marrow |
|
|
Sinuses are similar in structure to ___ but ___
Occur primarily in____ ___between endothelial cells |
sinusoids, larger in diameter
primarly in Spleen Large gaps between endothelial cells |
|
|
Damage to a capillary sets of for
|
clotting to occur
|
|
|
Substances cross capillary walls by(3)
|
Diffusing through endothelial cells
Fenestrae crossing between endothelial cells |
|
|
Types of molecules that diffuse through cell membrane
|
lipid soluble substances, small water soluble substances
|
|
|
Types of molecules that cannot readily pass through capillary walls
|
RBC,
large water soluble molecules(eg proteins) |
|
|
Precapillary sphincters
Regulate____ Consist of___ Located at__ |
regulate flow in capillaries
consist of smooth muscle cells located at branches of thoroughfare channels |
|
|
Precapillary sphincters set
|
set amount of blood volume in different areas based upon part of body used
|
|
|
Highly Metabolic tissues containing large numbers of capillary networks(4)
|
Lung
Liver Kidney Skeletal/Cardiac Muscle |
|
|
Capillary networks in skin function in
|
heat loss and thermoregulation
|
|
|
Capillary networks in muscle funciton
|
Nutrient and waste product exchange
|
|
|
Capillary network made up of (6)
|
Metarteriole
Arteriole Precapillary Sphincter Capillary Thoroughfare Channel Venule |
|
|
Layers of blood vessel walls(3)
|
Tunica Intima
Tunica Media Tunica Adventitia(externa) |
|
|
Vasa Vasorum
|
Small network of blood vessels that feeds larger blood vessels
|
|
|
Tunica Intima made up of
|
endothelium, basement membrane, lamina propria, and internal elastic membrane
|
|
|
Internal Elastic membrane separates
|
Tunica intima from tunica media
|
|
|
Tunica media consists of
|
Smooth muscle cells arranged circularly around vessel
|
|
|
Blood flow through vessel regulated by
|
contraction or relaxation of smooth muscle in tunica media
|
|
|
Tunica media contains variable amounts of
|
elastic and collagen fibers, depending on size of vessel
|
|
|
In some arteries, ____ separates tunica media from tunica adventitia
|
External Elastic membrane
|
|
|
Tunica adventitia composed of___and contains ___for anchoring
|
Dense or loose connective tissue
fibroblasts for anchoring |
|
|
Large elastic arteries:
____diameter ____pressure ____amount of elastic tissue ____amount of smooth mucle ___tunica intima ____tunica adventitia |
Large diameter
high pressure large amount of elastic tissue small amount of smooth muscle thick tunica intima think tunica adventitia |
|
|
Pressure in large elastic arteries ____between systole and diastole
|
Fluctuates between S and D
|
|
|
In large elastic arteries, amount of arterial stretch determined by
|
collagenous connective tissue
|
|
|
Pressure in large elastic arteries maintained by
|
elastic rebound
|
|
|
With age, ___restricts expansion of large elastic arteries, leading to ___
|
Calcification
increase in systolic pressure |
|
|
Increase in systolic pressure due to calcification results in less__, therefore ___is decreased
|
Less differential between S and D, pulse pressure is decreased
|
|
|
Large Elastic arteries found in
|
L side of heart, aorta
|
|
|
Muscular Arteries:
___ diameter walls are___compared to diameter Tunica media contains ____layers of ___ Tunica Intima has __ |
Medium diameter
walls thick compared to diameter TM contains 25-40 layers of smooth muscle TI has well developed internal elastic membrane |
|
|
In muscluar arteries, tunica adventitia is relatively ___
|
TA thick layer of collagenous connective
|
|
|
In muscular arteries, tunica adventitia partially___
|
partially regulates blood supply to diff regions through dialation and constriction
|
|
|
Arterioles transport blood from
|
small arteries to capillaries
|
|
|
Arterioles are the smallest arteries in which
|
the three tunics are identifiable
|
|
|
Arterioles are capable of
|
vasodilation and vasoconstriction
|
|
|
Arterioles carry
|
oxygenated, nutrient rich blood to capillaries
|
|
|
Capillaries connection between
|
arterioles and venules
|
|
|
Venules/Small veins comparable to
|
arterioles
|
|
|
Venules composed of
|
endothelium resting on basement membrane
|
|
|
Venules have few___, but small veins have a__
|
isolated smooth muscles cells
continuous layer of smooth muscle |
|
|
Nutrient exchange occurs across walls of____, but decreases as ___of vein ____
|
small veins
decreases as size of vein increases |
|
|
Medium and large veins have a thin____
|
thin tunica intima consisting of endothelial cells
|
|
|
Medium and large veins have a thin layer of____with scattered___
|
thin layer of collagenous connective tissue, few scattered elastic fibers
|
|
|
In medium and large veins, ___is thin with a layer of ____ arranged smooth muscle cells
|
Tunica media thin
layer of circularly arranged smooth muscle cells |
|
|
Predominant layer in medium and large veins
|
tunica adventitia
|
|
|
Valves are present in veins larger than
|
2mm in diameter
|
|
|
Valves consist of___
Many present in ___ More in ____extremities |
consists of folds of tunica intima
many present in medium veins more in lower extremities |
|
|
# of valves also dependent on
|
muscular activity
|
|
|
Vaso vasorum present in vessels greater than
|
1mm in diameter
|
|
|
Vasa vasorum forms___
|
capillary network in tunica adventitia and media
|
|
|
Arterivenous anastamoses allow
|
blood to bypass capillaries
|
|
|
Glomus AV anastamosis vonsists of
|
convoluted arterioles surrounded by collagenous connective tissue
|
|
|
Physiologic anastamoses occur in((4)
|
nail beds
terminal phalanges palm of hand sole of food |
|
|
AV anastamoses common in arease that
|
don't need large amount of oxygen
|
|
|
Pathological AV anastamoses a result of___
can lead to___ |
Injury, tumors
may lead to heart failure b/c of excessive increase in venous return |
|
|
Most blood vessels innervated by
|
unmyelinated sympathetic nerve fibers
|
|
|
Penis and clitoris innervated by
|
Parasympathetic(cholinergic) fibers
|
|
|
These vessels have the greatest innervation. why?
|
Small arteries, arterioles
control of metabolic activity |
|
|
Baroreceptors found in(3)
|
Carotid artery
aortic arch kidneys |
|
|
All blood vessels have
|
non-innervated cholinergic receptors
|
|
|
Baroreceptors are
|
myelinated sensory neurons that act as stretch receptors
|
|
|
Lymphatic vessels cary fluid
|
away from tissues
|
|
|
lymphatic vessels originate as
|
lymph capillaries
|
|
|
lymph capillaries lack___
and cells are__ |
lack basement membrane
cells are simple squamous epithelium |
|
|
lymph vessels located in all tissue EXCEPT(3)
|
CNS
bone marrow non-vascular tissue |
|
|
Lymph is moved by
|
Compression of lymphatic vessels
|
|
|
Lymph vessels compressed by
|
Skeletal muscle contraction
smooth muscle contraction thoracic pressure changes as a result of respiration |
|
|
Laminar Flow results from
|
high resistance to flow on outer layer of endothelial cells
|
|
|
Blood moves fastest at
|
Center of blood column
|
|
|
Shear stress stimulates
|
vasodilation
|
|
|
Turbulent flow occurs when
|
laminar flow is interrupted by constriction, branch, or rough surface
|
|
|
Vibrations during rurbulent flow produce
|
Korotokoff sounds, heart sounds
|
|
|
Turbulent flow usually indicates___
Increases probability of |
Abnormal constriction
inc probability of thrombosis |
|
|
Blood pressure is a measure of
2 methods of measurement |
Measure of force exerted by blood against wall
measured by cannula or using ausculatory method |
|
|
When taking BP, turbulence produces Korotokoff sounds as soon as
|
pressure declines below systolic pressure
|
|
|
Sounds dissapear when taking BP when
|
diastolic pressure, complete laminar flow restored
|
|
|
Rate of blood flow always proportional to
|
pressure difference in vessel
|
|
|
Flow always proceeds from
|
high pressure to low pressure
|
|
|
Viscosity is__related to blood flow
|
inversely related
|
|
|
Viscosity of blood influenced most by
|
hematocrit(% of RBC in whole blood)
|
|
|
Have a minimal influence of viscosity
|
plasma proteins
|
|
|
Viscosity can increase as a result of
|
dehydration, increased RBC production
|
|
|
Polycythemia treated with
|
blood letting
|
|
|
Critical closing pressure
|
pressure below which blood vessel collapses
|
|
|
Laplace's Law
|
F=D*P
force stretching wall directly proportional to diameter and pressure |
|
|
In an aneursym, increased diameter results in
|
greater pressure applied to weakened portion of vessel
|
|
|
Vascular compliance
|
Inc volume/Inc pressure.
volume of vessel inc as pressure increases |
|
|
Greater compliance means
|
a vessel stretches more easily
|
|
|
veins are ___ vessels
|
storage or compliance vessels
|
|
|
Venous compliance ___ times that of arteries
|
24 x that of arteries
|
|
|
Arteries are __ vessels
|
resistance
|
|
|
% of blood volume contained in systemic circulatory system
|
84
|
|
|
most of blood volume is in
|
veins
|
|
|
Cross sectional area of capillaries
|
2500 square centimeters
|
|
|
Velocity in blood flow is __ in arease where cross sectional area is high.
__velocity in aorta __velocity in capilaries |
velocity low in areas where area is high
high velocity low velocity |
|
|
Low velocity in capillaries allows for
|
more exchange to occur
|
|
|
Pressure falls as blood moves from ___ to ___
|
aorta to right atrium
|
|
|
Resistance highest in
|
arterioles and capillaries
|
|
|
Muscular arteries/arterioles constrict/dilate in response to
|
ANS or hormonal stimuli
|
|
|
Constriction increases resistance, which
|
decreases flow, shunts blood to other areas
|
|
|
Muscular arteries control flow to
|
each region of the body
|
|
|
arterioles regulate flow
|
locally, through tissues
|
|
|
Vasodilation decreases___and increases___
|
resistance, increases blood flow
|
|
|
Pulse pressure is
|
the difference between S and D pressures
|
|
|
2 major factors affecting pulse pressure
|
stroke volume
vascular compliance |
|
|
Pulse pressure produced by
|
Left ventricular ejection into aorta
|
|
|
A weak pulse(NOT pulse pressure) may indicate(5)
|
Decreased stroke volume
increased arterial constriction Partial or complete occlusion Low blood volume Heart weakness |
|
|
Highest pulse pressure found in
Lowest pulse pressure found in |
Aorta
Veins, venules, and vena cava |
|
|
At the arterial end of capillaries, fluid is moved by
|
small negative pressure in interstitial spaces resulting from compression of lymphatic fluid
|
|
|
Fluid is attracted into capillary by
|
Osmosis
|
|
|
Concentration of small molecules is___in interstitial fluid and blood
|
equal
|
|
|
Concentration of proteins is less in___than in ___
|
less in interstitial fluid than in blood
|
|
|
Pressure produced by plama proteins is termed
|
blood colloid osmotic pressure
|
|
|
Colloid osmotic pressure higher in___
|
higher in blood than in interstitial fluid
|
|
|
At arterial end of capillary, forces moving fluid out are(2)
|
Blood Pressure
Negative Pressure |
|
|
Net movement of fluid is ___capillary
|
out of
|
|
|
Blood pressure decreases from __ to __ between arterial and venous ends of cap
|
30 mmHg to 10mmHg
|
|
|
Concentration of proteins higher at___ end of cap
|
venous end
|
|
|
% of fluid that reenters venous end
% of fluid that enters lymphatics |
90% returns to cap
10% enters lymphatics |
|
|
Exchange of fluid can also result from
|
cyclic dilation and constriction of precapillary sphincter, forcing fluid into interstitial spaces
|
|
|
Cyclic dilation is the primary mechanism used in tissues
|
not compressed by movement
|
|
|
Preload is determined by
|
volume of blood that enters heart from vein
|
|
|
Venous tone is a continal state of
|
partial contraction(SNS stimulation)
|
|
|
Movement of blood thru veins a funtion of
|
muscular movements, venous valves
|
|
|
Nitrates
|
dilate peripheral veins
|
|
|
Arterial-Venule difference in pressure
|
30-10mmHg
|
|
|
Arterial-Venule difference in pressure while standing
|
110-90mmHg
|
|
|
In most tissues, blood flow proportional to
|
metablic needs of tissue
|
|
|
blood flow may increase in response to buildup of
|
metablic end products(locally)
|
|
|
Blood flow in kidneys regulates(3)
|
water balance
pH elimination of waste products |
|
|
Blood flow in liver
|
delivers nutrients from small intestine for metabolism
|
|
|
Long term reg of blood pressure done by
|
kidney
|
|
|
T/F: Metaarterioles and precapillary sphincters are heavily innervated
|
False. Metarterioles and sphincters have sparse innervation.
|
|
|
Vasodilator Substances(8)
|
Carbon Dioxide
Lactic Acid Adenosine AMP ADP EDRP K ion H ion |
|
|
Lack of ___ also serves role in regulation
|
lack of nutrients
|
|
|
Lack of oxygen and other nutrients results in
|
relaxation of smooth muscles cells of sphincters
|
|
|
Blood flow through capillaries is ___, not __.
|
Cyclic, not continuous
|
|
|
Arterial pressure ___, while flow through tissue __
|
fluctuates widely over a wide range,
flow through tissue remains constant |
|
|
Afteral pressure fluctuates approx ___ mmHG, and flow through tissue remains within __% of normal
|
75 to 175 mmHG
10-15% of normal |
|
|
Factors responsible for autoregulation(2)
|
Need for Nutrients
Buildup of waste |
|
|
Long-term flow matched to
|
metabolic requirements of tissue
|
|
|
If metabolic activity increases fro extended period of time,
|
diameter and number of caps increases
|
|
|
Major factor in adjustic vascularity
|
availability of oxygen
|
|
|
Nervous regulation of local circulation important for
|
Minute-to-minute regulation of BO
while at rest or exercise |
|
|
Nervous regulation aids in maintaining flow to
|
brain and heart
|
|
|
moment-to-moment control done through
|
ANS, primarily sypmathetic
|
|
|
Nervous regulation can change within
|
1-30 seconds
|
|
|
Most of neural regulation is through__, which innervates ___
|
SNS
innervates small arteries/arterioles to inc or dec resistance |
|
|
SNS vasocontrictor fivbers distributed to___
More prominent in(2) Less prominent in(4) |
most parts of circulatory system
more prominent in skeletal muscle, cardiac muscle less prominent in kidneys, gut, spleen, skin |
|
|
Inc epinephrine release can lead to
|
vasodilation
stimulation of beta 2 receptors |
|
|
Vasomotor center found in___ and is ____
|
lower pons and upper medulla
tonically active |
|
|
Partial state of constriction(vasomotor tone) maintained by
|
low frequency of impulses
|
|
|
Vasomotor center has both
|
vasoconstrictor(tonically active)
vasodilator(inhibitory) |
|
|
Vasoconstrictor SNS fibors release
|
epinephrine
|
|
|
epinephrine and norepinephrine can also be released from
|
adrenal medulla
|
|
|
Mean arteral pressure equation
|
MAP= 1/3(pulse pressure)+DBP
|
|
|
Mean arterial pressure not average of systolic and diastolic because
|
diastole is longer than systole
|
|
|
MAP=
|
COxTPR
|
|
|
Cardiac Output=
|
SV*HR
|
|
|
Which side of heart pumps more volume
|
both sides pump equal volume
|
|
|
which side of heart generates greater pressure
|
left side
|
|
|
Short term regulation of BP by(4)
|
Baroreceptors
Chemoreceptors CNS ischemic reflex Adrenal medullary mechanism |
|
|
System of nervous regulation
|
Vasomotor center in MO-->sympathetic chain--->sympathetic nerve fibers-->blood vessels
|
|
|
Baroreceptors generally adapt to a new blood pressure in
|
1-3 days
|
|
|
If blood pressure goes down:
__ parasymp, __ sympathetic |
decreased parasymp
increased sympathetic |
|
|
If blood pressure goes up:
|
Decreased sympathetic
Increased parasympathetic Increased vagus nerve stimulation More Ach release Less vasoconstricton Slower Heart rate Discrete release of ACh |
|
|
Chemoreceptor reflexxes help to
|
maintain homeostasis when oxygen tension in blood decreases, or when CO2 and H increases
|
|
|
Chemoreceptors located in
|
carotid sinus
aortic bodies |
|
|
chemoreceptors act under
|
emergency conditions; do not normally regualate CVS
|
|
|
Activation of Chemoreceptors results in
|
increased BP to increase perfusion(washing out of metabolites)
|
|
|
Chemoreceptor Reflex
|
Chemoreceptors in aortic bodies-->glossopharyngeal/vagus nerve-->chemoreceptors in MO--->vagus nerve(parasympathetic)-->sympathetic nerves, sympathetic chain
|
|
|
Adrenal medullary mechanism activated by
|
stimuli that increase SNS stimulation
Inc |
|
|
Adrenal medullary mechanisms leads to
|
inc release of EPI and NE from medulla
|
|
|
CNS ischemic response activated by
|
decreased blood supply to medulla
|
|
|
CNS ischemic response stimulated by
|
buildup of CO2 and H
|
|
|
CNS ischemic response initiates
|
severe SNS discharge, large amounts of vasoconstriction, shunting of blood to CNS
|
|
|
CNS ischemic response initiated only when
|
BP falls below 50 mmHG
|
|
|
Long-term regulation of BP done by(5)
|
Renin-angiotensin-aldosterone
Vasopressin ANF Fluid Shift Stress-Relaxation |
|
|
Renin-AII system:
Renin release stimulated by |
decreased renal blood flow
reduced plasma sodium |
|
|
Renin-AII system:
Aldosterone released due to |
decreased plasma sodium
elevated plasma potassium |
|
|
Renin-AII system:
how long before activated? |
20 min
|
|
|
Renin-AII system:
remains active for? |
1 hour
|
|
|
Renin-AII system:
Mechanism |
Renin released in response to low BP
Renin stimulates convesion of Angiotensinogen to AI ACE in lungs stimulates conversion of AI to AII AII stimulates vasoconstriction and the adrenal cortex to release aldosterone |
|
|
Function of aldosterone
|
Inc water retention
dec urine volume |
|
|
Vasopressin secreted from ___ in response to
|
posterior pituitary
Decreased BP Inc concentration of solutes in plasma |
|
|
Vasopressin acts directly on
|
blood vessels to cause vasoconstriction
rate of urine production |
|
|
Vasopression mechanism
|
Osmoreceptors detect inc osmotic pressures, baroreceptors detect dec pressure-->stimulation of post pituitary-->release of ADH
|
|
|
ANF released from
stimulated by |
cells in atria
stimulated by elevated atrial pressure |
|
|
ANF action(3)
|
Inc rate of urine production
Inc excretion of sodium Vasodilation of arteries and veins |
|
|
Fluid-Shift mechanism acts within ___ and maximal effect in ___
|
a few minutes
a few hours |
|
|
Fluid shift occurs in response to
|
changes in pressure across capillary walls
|
|
|
Fluid shift mechanism
|
If BP inc too much, fluid is forced out of capillaries
|
|
|
Interstitial fluid volume acts as
|
reservoir for blood
|
|
|
Stress-relaxation acts in response to
|
sudden decline in BP
|
|
|
Stress relaxation mechanism
|
Sudden reduction in force applied to smooth muscle cells
|
|
|
Methods to dec blood pressue(4)
|
Fluid Shift
Stress Relaxation ANF Renin-AII |
|
|
Methods to inc blood pressure(4)
|
Renin-AII
Vasopresin Stress Relaxation Fluid Shift |
