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Blood Vessels
Anatomy and physiology
43
Biology
Undergraduate 2
06/10/2008

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Term
ECG during a heart attack
Definition
-T wave inversion
-ST elevation > funny RT wave
-ischemic injury > Q is really big
Term
Why most MI's in early am
Definition
-increased vascular tone in am
-BP is slightly increased
-accelerated blood coagulation
Term
CNS influence on HR
Definition
-HR responsive to activity, stress, temp, anxiety
-regulated through autonomic NS
-sympathetic > accelerator nerves synapse with SA/AV + myocardium
-Parasympathetic - cardio-inhitor in medulla by way of vagus nerve
Term
Chem influences
Definition
-epinephrine, thyroxine > +HR
-+Ca > cardiac depression, cardiac irritability
--Ca > depressed unresponsive heart
-+K > heart block
--K > feeble beating, weak heartbeat
Term
Arterial wall
Definition
-thicker than veins 5-6 x
-endothelium
-middle layer
-outer layer
Term
endothelium
Definition
-inner layer
-smooth, single layer of squamous epi
Term
middle layer
Definition
-tunica media
-bulk of wall
-smooth muscle w/ thick layer of elastic connective tissue
-withstand BP
-stretches
-vasoconstricts/vasodialtes
Term
outer layer
Definition
-tunica externa
-connective tissue with regular elastic collagenous fibers
-attaches artery to surrounding tissues
Term
properties of arteries
Definition
-innervated by autonomic NS
-vasomotor control
-taper to smaller arterioles > thinner layers
-metarterioles join with caps
Term
ArteriouVenous AV shunt
Definition
veins and arteries a joined directly without capillaries
Term
capillaries
Definition
-connection between arteries and veins
-extensions of endothelial lining of arteries
-one cell layer thick
-point of gas/nutrient exchange
-point of circulatory return
Term
capillary permeability
Definition
-pore size varies > largest in liver, spleen, marrow > allows large protein + cells to leave
-smallest > smooth, skeletal, cardiac muscle
-small/limited in brain to create blood/brain barrier
Term
high density capillary arrangement
Definition
-tiisue w/ high metabolic demand
-muscle and nerves more O2 and nutrients
Term
low density capillary arrangement
Definition
-slow metabolism > tendon, ligament, coenea
- don't heal well
-don't bleed much
Term
cap. Pattern
Definition
-some caps pass directly from arterioles to venules
-others highly branched network
Term
exercise
Definition
precapillary sphincters relax and that increases flow to skeletal muscles
Term
digestion
Definition
flow increases in the GI track
Term
regulation of capillary flow
Definition
-changes in sympathetic tone
-controlled by precapillary sphincters
- ring of smooth muscle sensitive to changes in O2 + nutrients
Term
capillary exchange
Definition
3 forces
-difussion
-filtration
-osmotic pressure
Term
diffusion
Definition
-high to low concentration
-high O2 + nutrients into tissues
-from tissue high in CO2 > high metabolic waste out
-depends on lipid solubility > diffuse through cell membrane
-lipid insoluble > diffuse through pores in cell memb or slits in caps
Term
filtration (hydrostatic BP)
Definition
-high pressure in arteries vs. veins
- arteriolar end versus venular end
-hydrostatic pressure pushes small molecules through caps
-excess fluid picked up by lymph vessels
Term
osmotic pressure
Definition
plasma proteins in blood cause it to have higher osmotic pressure
-this causes fluid + wastes to be drawn into vessels
normally more fluid leaves the caps then reeturns
-lymph vessels collect excess fluid
Term
edema
Definition
-histamine > cap vasolidation > increased cap. permeability > too much fluid for lymph system
Term
venous walls
Definition
-thinner walls
-elastic tissue
-low presusre
-veind of upper and lower limbs
-fuction as blood reservoir
-loss of blood > sympathetic
-vasoconstriction occurs to increase bp
Term
blood moved back to heart
Definition
-one way valves
-massaging action of skeletal muscle
-negative pressure of chest
Term
Normal BP
Definition
110-140/60-90
s/d
s > ventricular contraction
d > ventricular filling
Term
pulse
Definition
expanding and recoiling of arterial wall
Term
pulse sites
Definition
-radial > wrist
-brachial > arm
-carotid > neck
-femoral > inner thigh
-temporal > head
-popliteal > behind knee
-facial > jaw bone
- post tibial > anckle joint
-dorsalis pedis >top of foot
Term
factors affecting BP
Definition
-C.O.
-Stroke volume and blood discharged from ventricles
-blood volume
dehydration, hemorrhage > lower BP
-Systemic Vascular Resistance SVR > friction between blood vessels
-viscosity BP up
-polycythemia > adaptation to high altitudes
Term
Control of BP
Definition
-mechanical regulation
-nervous regulation
-chmical regulation
-hormonal regulation
Term
Nervous regulation
Definition
-baroreceptors aortic arch + carotid sinuses > to cardiac center of medulla
-up BP > parasym > SA node > down HR cardioinhibitor reflex
-down BP sympath > SA node > Up HR cardioaccelerator reflex
-vasomotor in medulla reg blood vessel size
Term
mechanical regulation
Definition
-changes in strength of ventricular contraction assure a match of volume in and out
Term
chemical regulation
Definition
chemoreceptors for 02 and pH > aortic arch, carotid arteries, brain (pons) influences SVR, ebercise > up CO2, down O2, down pH > vasodilation up blood flow
Term
hormonal regulation
Definition
-adrenal medulla >fight/flight response epinephrin
-ADH antidiuretic hormone
-atrial natriuretic factor > high BP > secreted in atria > down SV and BV
Term
CAPILLARY HYDROSTATIC PRESSURE HPc
Definition
-fluid flow out
-tends to force fluids through the capillary walls
-greater at the arterial end
Term
capillary colloid pressure OPc
Definition
-fluid flow in
-created by nondiffusable plasma proteins, which draw water toward themselves
Term
Net Filtration Pressure NFP
Definition
-considers all forces acting on a capillary bed
-at the arterial end of a bed, hydrostatic forces dominate
-at the venous end of a bed, osmotic froces dominate
Term
circulatory shock
Definition
any condition in which blood vessels are inadequately filled and blood cannot circulate normally
-results in adequate blood flow to meet tissue needs
-3 types
-hypovolemic, vascular shock, cardiogenic shock
Term
hypovolemic shock
Definition
results from large scale blood loss
Term
vascular shock
Definition
poor circulation resulting from extreme vasolidation
Term
cardiogenic shock
Definition
the heart cannot sustain adequate circulation
Term
pulmonary circulation
Definition
short loop that runs from the heart to the lungs and back to the heart
Term
systemic circulation
Definition
routes blood through a long loop to all parts of the body and returns to the heart
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