Chapter 18

jennraq2u's version from 2015-09-19 20:23


x= Section
Question Answer
fenestrated structure( look at figure 18.3oval pores increase permeability than continous; areas of filtration absorpition=kidneys/SI/Endocrine glands
sinusoidal structure(look at figure 18.3most permeable; found only in spleen/liver/bone m/adrenal medulla.Larger lumens/clefts=blood cells/molecules to pass/sluggish blood flow
continuous structure(look at figure 18.3least permeable;most common=in skin/muscles; cells joined by tight junctions w/ incomplete intercellular clefts.pass fluids/small solutes
stellate macrophagesin liver hepatic macrphages remove/destroy bacteria
Arteriesblood flow into capillaries r/t arteriolar diameter
capillariesblood recieved here from arteries r/t neural/hormonal/chemical influences
veinscappliaries form to create venules; venules join to make veins; their walls are thinner & lumens larger than corresponding arteries;collapsed=lumens look slitlike
ArteriesR is more important that Pressure r/t local blood flow; arteries dilate, R is decreases=blood flow to that tissue increases even though systemic is unchanged
capillarieslow BP works in capillaries r/t 1)capillaries fragile 2)so permeable low flow is ok r/t can force solute fluids of blood into interstitial space
veinslow pressure blood flow ok r/t large lumens; venous valves r/t semilunar valves of heart; mostly in limbs; reflects effects of peripheral resistance/dissapates most energy of blood
Velocity of Blood Flowblood flows slowest=cross-sectional area is greatest size= in vascular bed/capillaries; aorta smaller cross section=faster blood flow
HTN Dangers strains heart/damages arteries/HF/vascular disease/renal falilure/stroke/enalrged myocardium/flabbywalls/athsclerosis
athlerosclerois & r/t Heart Disease blocked vessels=inadequate blood flow to tissues=complications in heart/retina/kidneys/brain
arterial anstomosesoccur in joints/ab organs/heart/brain
blood flow(ml/min) in entire vascular system=cardiac output; individual organs r/t need; proportional 2 diff in BP b/t 2 pts in circulation
BPforce per unit area exerted on a vessel wall by the contained blood(mm Hg)stytemic arterial BP in largest arteries near heart; area of higher pressure to lower pressure in body
Resistanceoppositon to flow=amount of friction blood encounters 2 pass thru vessels; mostly in systemic/peripherial resistance
Blood Viscoscityinternal resistance to flow exists in all fluids; r/t thickness/stickiness of blood
pulsatileBP is termed as this r/t it rises & falls in a regular fashion in the elastic arteries near the heart
systolic pressureas left ventricle contracts/expels blood into aorta w/ kinetic energy=aorta pressure higher than distal vessels=120mm
diastolic pressurevolume/energy of blood in elastic arteries during systole, given back @ diastole;aortic valve closes/walls of aorta recoil=70-80mm
pulse pressurediff b/t systolic and diastolic pressure; athsclerosis increases pulse pressure r/t artieries less stretchy
mean arterial pressure (MAP)equal 2 teh diastolic pressure plus one-third of the pusle pressure; MAP & PP decline w/ distance from heart
muscular pumpas skeltal muscles around deep veins contract/relax; milk blood toward the heart; skeletal inactivy=fainting/reduces venous return
respiratory pumpinhale=ab pressure increases squeezing veins/blood toward heart; pressure in chest decrease=veins expand=speeds blood entry into RA
sympathetic venoconstrictionas layer of smooth msucle around veins constricts r/t sympathic control=venous vol reduced/blood pushed toward heart
short term regreg by nervous system/hormones r/t change peripheral resistance & CO
Long term regalters blood volume via kidneys
baroceptersBP falls/when stretched=make cardiovascular center inhibit vasomotor/cardioaccelatory=stim cardioinhibitory
BP Barocepter falls b/cArteriorlar vasodilation*Venodilation*Decreased Cardiac Output
Standing Up after recliningBP falls in head r/t carotid sinus reflex
Blood Volumedetermines CO r/t venous return/EDV/Stroke Volume influences
BP can be stabalizedWNL only when blood volume is stable
direct renal mechanismalters BV w/o hormones
indirect renal mechanismalters BV w/ homone renin-angiotensin-aldosterone mechanism=triggers thirst=reabsorption of H2O by kidneys
pulsepressure wave transmitted thru arterial tree
pressure pointscompressed to stop blood flow during hermorrage
Nitric oxidevasodilator actis via GMP 2nd messenger system; overrides vasconstriciton if tisseus need more blood
metabolic inrinsic control mechanismimmediate vasodilation of arterioles serving capillary beds of needy tissues/precapillary sphicnters
myogenic intrinsic control mechanismmyogenic responses=vascular smooth muscle responds to passive stretch w/ increased tone=vasconstriciton/Re'd stretch w/vasodilation
Pulmonary Systemhi in O2=vasodilation; p. 626 IP1
Only way to provide more O2 to a vigoursly working heartincrease the blood flow
vasomitionon/off opening/clsoing of precapillary sphincters=intermittent/slow blood flow
diffusionCarbon dioxide/wastes leave the cells where their content is hi, diffuse into capillary blood where content is low (p. 626 IIP7
bulk fluid is forced out of capillaries r/t clefts@arterial end of bed & returns to bloodstream via venous end
Bulk Flow determines relative fluid vol inbloodstream & interstitial space
Capillary Hydrostatic Pressurevia filtration process; BP drops as Blood Flows along capillary bed; HP(c) higher @arterial end of bed then venous end (p.626 IIP11
Interstitial Fluid Hydrostatic PressureActs outside capillaries pushing fluid in; Opposes BP that forces fluid out of the capillaries=traditionally number is 0
Colloid Osmotic Pressurepulls in or sucks r/t osmosis from diffusible molecules=opposing hydrostatic pressure (pushes) stays same @ each end of bed p. 627 IIP1
Capillary colloid osmotic pressure aka oncotic pressurer/t lots of plasma proteins in capillary blood (26mm); Interstitial fluid few proteins=0.1-5mm
While net filtration occurs @ arteriorolar end of cappillaryNegative value for NFP @ venous end=fluid moves into capillary bed (reabsorpition)
Net Fluid Flowout of circulation @ arterial ends of capillary beds; into the circulation @ venous ends; more tissue enters tissues than returns 2 blood
Venous blood draining from organs below diaphragmreturn to Right Atrium via Inferior Vena Cava
Venous blood draining from organs above diaphragm exceptsome Coroanry/Thoracic (Azygos system veins) return to Right Atrium via Superior Vena Cava