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298 Cards in this Set
- Front
- Back
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carry blood away from heart
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arteries
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efferent
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artieries
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return blood to the heart
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afferent
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microscopic vessels where exchange of gases and solutes occurs between the blood and tissues
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capillaries
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includes endothelial lining & an underlying layer of connective tissue
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tunica interna
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contains concentrc sheets of smooth muscle tissue in a frameowrk of loose connective tissue
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tunica media
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commonly the thickest layer in the wall of an artery
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tunica media
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outermost layer
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tunica externa
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in veins, this layer is generally thicker than the tunica media and can contain smooth muscle
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tunica externa
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in veins it is the dominant layer
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tunica externa
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the connective tissue of the _____ tends to blend with neighboring tissues . this stabilizes and anchors the vessel
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tunica externa
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usually round, retain their shape in sectional view
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arterial wall
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thick wall
small lumen --compared to its accompaying vein |
arterial wall
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innermost layer; endotheial lining and underlying layer of connective tissue; appears rippled or scalloped due to elastic fibers
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tunica interna / tunica intima in arteries
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middle layer ; consists of relatively thick layer of smooth muscle with abundant elastic fibers ; thickest layer
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tunica media in arteries
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outermost layer; consists primaliry of connective tissue ; (mostly collagen fibers)
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tunica externa in arteries
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flattened / collapsed in sectional view
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wall of vein
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thin wall
large lumen |
wall of vein
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thinner-walled due to its counterpart artery
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wall of vein
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thickest wall is tunica externa
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wall of vein
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may contain valves
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wall of vein
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innermost layer ; endotheial linging and underlying layer of connective tissue; no internal elastic membrane ; appears smooth
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tunica interna / tunica intimia
of veins |
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middle layer; thin layer of smooth muscle; with collagen fibers
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tunica media of veins
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outermost layer; consists primarily of connective tisse of collagen and elastic fibers ; smooth muscles are present in larger veins
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tunica externa in veins
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general appearance in sectional view:
--round --thick walls --smaller lumen |
artery
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general apperance in sectional view:
--flattended or collapsed --thin wall |
vein
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tunica interna : endothelium --
--rippled due to vessel constirction |
artery
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tunica interna: endothelium --
-- often smooth |
vein
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tunica media--
--thick --dominated by smooth muscle & elastic fibers |
artery
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tunica media--
--thin --dominated by smooth muscle & collagen fibers |
vein
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tunica externa --
--collagen fibers --elastic fibers |
artery
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tunica externa--
--collagen fibers --elastic fibers --smooth muscle fibers |
vein
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___ contain smooth muscles and elastic fibers . This is because arteries are invovled in blood pressure control
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arteries
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both elastic & contractile
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Artieries
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___ permits passive changes in vessel diameter in repsonse to changes in blood pressure . it allows arteries to absorb the pressue changes associated with ventricular systole and diastole ... (doesnt move muscle)
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elasticity
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__permits contraction and relaxation of muscle within the wall of blood vessel .
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contractility
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when smooth muscle is stimulated (contracts) , arteries ____ & diameter of the lumen decreases
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vasoconstrict
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relaxation of smooth muscle (______) causes an increase in the diameter of the lumen
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vasodilation
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__doesnt go back to its original shape
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compliant
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___ arteries or conducting artieres
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elastic
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___ are large vessels with a diameter up to 2.5 cm or 1 inch
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elastic arteries
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ex: pulmonary arteries & aorta
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elastic arteries
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____ arteries transports large volumes of blood from the heart
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elastic arteries
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during ventriculuar systole , blood is ejected into elastic artieries and they expand. During ventricular diastole , elastic arteries recoil (cz of their elasticity) and return to their orignial size
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elastic arteries
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__ the expansion of elastic arteries cushions the sudden rise in blood pressure during ventricular systole and their recoil slows the drop in pressure during verntricular diastole
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elastic arteries
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___ this allows blood flow within the artieries to be continous even though blood flow from the heart is discontinuous
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elastic arteries
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__ artieries or medium sized arteries
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muscular arteries
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__ distrubutes blood to the bodys skeletal muscles and organs
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muscular arteries
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ex: external cartoid artieres of neck, brachial arteries of arm and femoral arteries of thigh
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muscular arteries
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__ arteries known as distributing arteries cz they distribute blood to the bodys skeletal muscle and internal organs
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muscular arteries
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__ characterized by a thick tunica media containing more smooth muscle than that of elastic arteries
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muscular arteries
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__ internal diamete of 30 micrometers or less. no tunica externa; tunica media consists of 1 or 2 layers of smooth muscle
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arterioles
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have biggest effect on changing blood flow based on resistance
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artierioles
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arterioles are referred to as this... even though arterioles have less muscle , they are vessels whose diamter changes to cause great differences in the flow of blood
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resistance vessels
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__ the force opposing blood flow
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resistance
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more pressure is required to push blood through a ___ vessel than a ___ vessel
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constricted ; dialated
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___ are blood vessels that allow for the exchange of nutrients and gases to the interstitual fluids due to tissue anatomy and the slow rate of blood flow through them
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capillaries
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__ connects arteries to veins
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capillaires
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millions of ____ are found in the body
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capillaires
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___ is one layer thick of endotheial cells lying on a basement membrane
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structure of the capillary
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__ holds epitheial cells together and to surrounding tissue; composed of fine fibers of collagen
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basement membrane
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average diameter of capillaries
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7.5-8 micrometers.. close to the size of a RBC
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__ capillary lining is complete ; allows diffusion and pinocytotic transport of gases and nutrients with the loss of no plasma proteins ; most common
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continuous capillaries
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__ capillaries can be found in skeletal muscle
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continuous capillaries
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___ capillaries with small pores between endotheial cells ; the pores allow for rapid exchange of water and solutes (even small proteins).
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fenestrated capillaries
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___ capillaries are located in areas in need of rapid exchange
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fenestrated capillaries
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pinocytotic transport is present in these capillaries
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fenestrated capillaries
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___ capillaries can be found in endocrine glands & kidney
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fenestrated capillaries
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___ or discontinuous capillaries
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sinusoids
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wide open / flatenned specialized fenestrated capillaries
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sinusoids
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___allows for freee exchange of water, solutes, large proteins, and cells
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sinusoids
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blood moves into sinusoids slow or fast?
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slow
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these capillaries can be found in the liver, lymphoid organs, bone marrow.... (recycling of blood)
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sinusoids
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___ exists within an interconnected network of many vessels
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capillary beds
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____ will give rise to dozens of capillaries that empty into venules
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a single arteriole
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___ the entrance to each capillary is guarded by muscular sphincters that can constrict and thus retrict blood flow to the capillary
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pre-capillary sphincters
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___ main vessel with the capillary bed
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metarteriole
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capable of dilation or constriction and therefore controlling blod flow through a capillary bed
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metarteriole
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__ collect blood from capillary beds... may resemeble a capillary
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venules
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__ collect blood from venules; have a thin tunica media with few smooth muscles; tunica externa thickest layer
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medium sized veins
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___ collects blood from medium sized veins ; all layers are present
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large veins
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ex: superior & inferior vena cava
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large vein
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__ folds of the tunica intimia
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valves
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its function is to prevent backflow of blood into capillary network ; keeps blood flowing in one direction
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valves
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blood pressure is below the force of gravity in what?
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veins
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the ___ muscle contractions that constrict veins in cycles so that blood will be pushed toward the heart
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skeletal muscle
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% volume of blood in heart, arteries, and capillaries
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35%
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% of blood volume in veins
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65%
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aprox. 5 liters of blood within the ___
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closed circulatory system
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veins are called ___ vessels because they are easily distensible and large changes in blood volume have little effect on blood pressure
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capacitance
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___ have capacity to hold alot of blood... serve as the blood reservoir
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veins
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___ of the veins will have a significant effect on the redistribution of the toatl blood volume
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vasoconstriction
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in ___ blood flows from one capillary system into another instead of back to the general circulation
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portal systems
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in ___ blood from systemic circulation into liver then into the heart , the portal system allows the liver to filter the blood before it enters the general circulation
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hepatic portal system
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the diameter of arteries __ as they approach capillaries
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decrease
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the diameter of veins __ as the approach the heart
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increase
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the cross sectional area of arteries __ as they approach the capillaries
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increases
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the cross sectional area of veins __ as they approach the heart
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decreases
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the circulatory system is a ___ system
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closed
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blood is a fluid ; fluids can/cannot be decompressed?
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cannot
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closed circuit system= blood must ___
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continue to move
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increase in volume of blood in one area = ___ in other area
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decrease
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(L/min)
same as cardiac output |
blood flow
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___amount of blood flowing through an organ, tissue, or vessel in a given time
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blood flow
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if flow does not keep pace with tissue metabolism , ___ may take place (tissue may die from oxygen deprivation)
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tissue necrosis
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total flow is constant and equal to cardiac output in a ___ individual
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resting indivdual
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__ of blood flow is equal to total cross sectional area of that part of the circulation
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velocity
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consider all vessels in an area in __
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velocity
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formula for velocity
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velocity = 1 / total cross section area
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arteries have a __ cross section area = __ velocity
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small = fast
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capillaries have a __ cross section area= __ velocity
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large = slow
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aorta has a cross section area of __
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4.5 cm2
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millions of capillaries with a __ amount of cross section area
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great amount of
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veins have a __ cross section area = ___ velocity
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small= fast
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__ study of physiological principles that govern blood flow
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hemodynamics
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__the amount of tension the contracting ventricle must produce in order to force open the semilunar vavle and eject blood
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afterload
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cardiac output=
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(SV) (HR)
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blood flow=
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cardiac output
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__ is the volume of blood moving through a given area in a given time
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blood flow
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factors affecting blood flow
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pressure & resistance
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__ pressure - a force exerted against a fluid
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hydrostatic pressure
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in a ___- hydrostatic pressure will push a liquid from high --> low concentration
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pressure gradient
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__ pressure= within the systematic circulation ... pressure difference between the beginning of the aorta to the entrance into the right atrium
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circulatory pressure
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--- is the force per unit area exerted on the wall of a blood vessel by its contained blood
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blood pressure
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___ mean artierial pressure
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blood pressure
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range of 100mm-35mm Hg
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blood pressure
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___pressure within capillary beds
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capillary pressure
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range of 35 mm-18mm Hg
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capillary pressure
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pressure within the venous system
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venous pressure
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range of 18 mm Hg - almost zero
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venuos pressure
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__ peak blood pressure measured during ventricular systole (contraction)
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systolic pressure
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__ min blood pressure at the end of ventricular diastole (relaxation)
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diastolic pressure
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__ the difference between systolic pressure and diastolic pressure
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pulse pressure
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indicates the force of contraction by the ventricle
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pulse pressure
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the size of the pulse pressure is determined by 2 factors--
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--stroke volume (which is dynamic)
& --elasticity of arteries (relativiely constant over time) |
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when blood vessels become less elastic there is a __ in blood pressure
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increase
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___ although arterial pressure fluctuates... this single value is used to represent conditions within the body
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mean aterial pressure
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map formula
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MAP = diastolic pressure + 1/3 (pulse pressure)
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blood pressure = systolic / diastolic
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120/80
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most of the decline in pressures occurs at __
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the small arteries & arterioles
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arterial pressure is __
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pulsatile (up & down)
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ventricular systole (aterial walls expanding) & ventricular diastole (ventricles recoil).. this process
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elastic rebound
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__ any force the opposes motion
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resistance
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__ resistance of the entire circulatory system
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total peripheal resistance
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__ the resistance of the parterial system ( for blood to flow into the capillaries the pressure gradient must be greater then the peripheral resistance )
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peripheal resistance
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__ the resistance of blood vessels
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vascular resistance
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__ the most important factor in vascular resistance is this between the blood and vessel walls
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friction
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__ thickness of the fluid
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viscosity
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thicker / more viscosius the fluid is =
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greater the resistance
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an increase in formed elemtns or large proteins = __ viscosity & __ resistance
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increase & increase
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__ blood movement ... increase this = increase resistance
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turbulence
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vascular resistance due to friction depends on 2 factors
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vessel length & vessel diameter
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increasing the length of blood vessel __friction
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increase
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smaller the diameter of vessel =
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greater resistance
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most peripheal resistance ooccurs where ?
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in the aterioles-- the resistance vessels
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resistance formula
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resistance = vessel length x viscosity of blood / (vessel radius)4
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a change in __ has a much greater afffect on resistance than any other factor
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radius
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what happens if the length of a vessel doubles?
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resistance increases (doubles) , = blood flow decreases
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what happens if the radius of a blood vessel doubles?
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the blood vessel will be 1/16 as resistant or 1 / (2)4 ... or to maintain constant pressure, the cardiac output (blood flow) will have to increase by 16 fold.
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small changes in diamter causes __ changes in resistance
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large
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___ can dynamically adjust their diameters
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arteriols
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__ contain more smooth muscle in their walls than other arteries
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arterioles
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the way that the smooth muscle is arranged (circularly) allows for the arteriole to contract and the lumen of the arterioles to ___ in diameter
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decrease
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__ & __ provides a mechanism by which arterioles can adjust blood flow through different tissues
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high resistance & variable meter
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resistance to blood flow is determined by ___
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the rsistance of the arterioles
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parallel circuits can be adjusted by __ of arterioles
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diameter
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___ can regulate the local flow of blood
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the individdual tissue beds
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cardiac output formula
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cardiac output= arterial pressure / resistance to flow
(CO) = P /R |
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cardiac output has a __ relationship to pressure and __ relationship to resistance
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direct ; indirect
up CO ; up pressure up CO ; down resistance |
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P = (CO) (R)
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CO = P / R
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how much pressure must the heart generate to overcome its resistance?
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the resistance to blood flow must be about three times greater in the systemic circulation thatn the pulmonary circulation
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most tissues are no more than -- cells away from a capillary
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3-4
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__ a thin waller vessel, consisting of a single layer of endotheial cells just wide enough for a blood cell to squeeze through.
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capillary
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the ___ of a capillary facilitates rapid duffusion or transport of materials into or out of the circulation
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the anatomy of the capillary
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___ is at the junction between the arterioles and capillaries. they control blood distribution into capillary networks
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muscular sphincters
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at any moment __ % of the capillaries are open & thus __% of all the blood is in the capillaries at any one time
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30-50% ; 5-7%
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__ net movement of molecules from high --> low concentration
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diffusion
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__ occurs most readily in areas where the concetration gradient is large; the distances are small and the substance ion is small
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duffusion
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difussion occurs by 5 routes
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--membrane channels
--through cell membranes --pores of fenestrated capillaries --between adjacent cells of a capillary --openings in sinusoids |
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__ ions diffuse in this manner
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membrane channels
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__ lipid soluble molecules (fats) difuse in this manner
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through cell membranes
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__ water, ions, small organic molecuules (such as glucose) and larger water-soluble molecules can diffuse in this manner
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between adjacent cells of a capillary
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__ all substances including large plasma proteins and blood cells can diffuse in this manner
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openings in sinusoids
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__ the movement of a fluid across a membrane whose pores restrict the passage of solutes on the basis of the size
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filtration
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in __ water is forced between adjacent capillary beds or pores of fenestrated capillaries into the interstitial fluid
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in capillaries
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blood pressure in a capillary is__
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capillary hydrostatic pressure (CHP)
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__ occurs as a result of differences in osmotic pressure across a membrane.
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reabsorbtion
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in __ water is reabsorbed from the interstiutial fluids into blood plasma due to high osmotic pressure in plasma
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in capillaries
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osmotic pressure is __ in plasma due to high concentrations of plasma proteins- mainly __?
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high ; albumin
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osmotic pressure of blood is __
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blood colloid osmotic pressure (BCOP)
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only the suspended proteins (colloid meaning proetins) cannot cross the cell membrane in this
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blood colloid osmotic pressure
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the rate of filtration and reabsorbtion __ throughout the capillary
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isnt the same
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__ ranges between 35-mm Hg at the arterial end of a capillary to 18 mmHg at the venous end
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capillary hydrostatic pressure
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__ hydrostatic pressure exerted on the capillary in the interstital fluid. this valve is negligible in most tissue fluids of the body
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hydrostatic pressure of the interstital fluid
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__ is the differnce between CHP & IHP
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net hydrostatic pressure
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IHP is almost zero , so net hydrostatic pressure is considered to be the same as --?
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CHP
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within capillaries, net hydrostatic pressure tends to __
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push water and dissolved solutes out of the capillary
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__ is roughly 25 mmHg along the entire length of the capillary
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blood colloid osmotic pressure (BCOP)
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__ is the osmotic pressure driving water into the interstitual fluids around the capillary from the blood plasma. this valve is negigible in most tissue fluids of body since they are nearly proteins free
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interstital fluid colloid osmotic pressure
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the difference between BCOP and ICOP
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net osmotic pressure
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the pressure differnce between the net hydrostatic pressure and net osmotic pressure
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net filtration pressure
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at __ end of the capillary, blood pressure (hydrostatic pressure) is high, and greater than the plasma colloid osmotic pressure . thus fluid flows out of the capillary
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at the arterial end of the capillary
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at __ end of the capillary, blood pressure (hydrostatic pressure) is low, and less than the plasma colloid osmotic pressure. Thus fluid flows into the capillary
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at the venous end of the capillary
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in general, more fluid is lost __ the vessel than is recaptured
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out the vessel
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thiis fluid flows into the ___ and is returned to the general circulation
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lympahtic system
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what happens in the event of dehydration?
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plasma experiences a decrease of water and therefore an increase of osmotic presssure . this accelerates reabsorption
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what happens in chronic high blood pressure?
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capillary hydrostatic pressure is elevated resulting in an increase in filtering of fluids into the interstitial fluids. excess fluids into thee interstitial fluids results in edema
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excess fluids into the interstitial fluids results in ?
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edema
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venous pressure determines ?
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venous return
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veins offer __ resistance & pressure __
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little resisstance and pressure declines slowly
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velocity of blood __ as it returns to the heart
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increases
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2 factors aid in overcomming gravity:
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muscular compressions of veins & the respiratory pump
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__ involves the expansion of the thoracic cavity, which reduces pressure
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respiratory pump
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__ is when capillary blood flow adjusts to meet the demands of the tissues- both oxygen demands and nutrient demands
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cardiovascular regulation
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when a group of cells or tissues become active blood flow must __ in order to delvier oxygen and nutrients needed for metabolism and to carry away waster product (acid) and carbon dioxide they generate.
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increase
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__ __ & __ are the variable controls
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BP CO PR
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important that cardiovascular regulation occurs __ __ &__
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-- at an appropriate time
--in the right atria -- and wihout drastic changes in the blood pressure or blood flow to any vital organs |
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__ autoregulation; immediate and local homeostatic adjustments
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local factors
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__ central control that hinges on regulation of arterial blood presssure in order to maintin blood flow to essential organs . immediate response
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neutral control
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__ substances produced by tissues of the endocrine system to cause a response that is central, delayed and withs hort and long term effects
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hormones
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local factors =
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autoregulation
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factos that change the pattern of blood flow within capillary beds in response to chemical changes in the interstitial fluids
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local factors
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the bility of individual vascular beds to maintain constant blood flow is ?
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autoregulation
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blood flow in most tissues __ in proportion to the metabolic demand of the tissue
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increase
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ex of __ = during strenuous excercise, blood flow may increase up to twenty times over resting levels <-- thats called?
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example of autoregulation..
active hypermia |
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autoregulatioin causes __ & __ adjustments
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immediate & localized homeostatic adjustments
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____?:
-increase in tissue levels of carbon dioxide -decrease in oxygen -the generation of metabolic acids by tssue cells - elevation of local temperatures -vasodilation paracrines |
loc al vasodilators
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__ chemical substances that have an effect on tissues close to where the substance is released
ex: histamine |
vasodilation pacrines
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__ cause constriction of blood vessels to decreasse blood flow
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local vasoconstrictors
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autonimc reflex & vasoconstrictor pacrines
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local vasoconstrictors
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__ an increase in blood pressure on the wall of an arteriole will cause a reflx that results in vasconstriction
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autonomic reflex
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__ substances released by damaged endothelial cells that line blood vessels
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endothelins
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central (neutral) control hinges on regulation of __
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arterial pressure
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__ is adjusted to maintain capillary flow to vital tissues and organs ( mainly the brain, heart, liver, and skeletal muscle )
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arterial pressure
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if all capillaries were open at the same time , massive and complete vasodilation of all the vascular beds in the body would lead to ___ in blood pressure because the heart is not able to pump fast enough to mainting such a high rate of blood flow to all tissues
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a drop
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__ is also maintined to control capillary pressure and the compostion of the interstial fluid
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arterial pressure
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__ located in the medulla oblongata of the brainstem
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cardiovascular complex
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this complex intergrates info and regulates nerve responses for the cardiovascular system
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cardiovascular complex
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ONLY the __ portion of the autnomic nervous system controls activity of the blood vessels
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sympathetic
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most neurons innervating peripheal blood vessels in most tissues are __
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sympathetic
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__ lead to the stimulation of smooth muscles in the walls of arterioles and causes arteriolar constriction
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neurotransmitters (like norepinephrine)
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this is a very large group of nerves responsible for widespread vasoconstriction
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neurotransmitters
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__ are sypathetic constrictors are chronically active; under normal conditions , blood vessels are partially constricted
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vasomotor tone
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because of this, it is possible for dilation or further constriction of vessels to be effective in controlling peripheral resistance.
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vasomotor tone
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modest changes in vessel diameter = __ changes in resistance
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large
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if vessels are maximally consticted, the venous reserve can be __
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mobilized
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__ innervate blood vessels of the skeletal muscle, heart, and brain
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vasodilator neurons
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stimulation of these nerves will relax smooth muscle in the walls of arterioles, producing vasodilation. this is a small groupd of nerves
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vasodilator neurons
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the vasomotor complex only involves the ___
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sympathetic nervous system
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tissues (like skin) heavily rely on __ activity for controlling normal blood flow -- vasodilation is possible by simply __sypathetic activity
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sypathetic ; reducing
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a major function of neural stimulation is to __
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restrict flow of blood to non-essential organs during physocigolical stress
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flight and fight response is a __ response
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sypathetic
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the essential organs that require uninterupted blood flow either have __ sympathetic innervation than other non essential organs (skin, GI tract) or are innervated by nerves that cause ___
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less ; vasodilation
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a mjor role of sypathetic innervation of the arterioles in peripheal (non essentail) tissues is to prevent cardiovascular collapse under conditions of physoilogical stress by reducing ___
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blood flow to non critical areas
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__ relexes response to changes in blood pressure; they are specialized receptors that monitor the degree of stretch in the walls of expandable organs
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baroreceptor
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__ consists of finely branched nerve endings on blood vessels from the aortic sinuses and the cartoid sinuses
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baroreceptor
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baroreceptors respond to _
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the stretch of the arery wall, not directly to pressure
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information from the baroreceptors is relayed through the ____ in the __
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cardiovascular center in the medulla oblongata
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CO = ?
or P =? |
CO= P / R
or P = CO x R |
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if mean arterial blood pressure (MAP) elevates: the body responds by __ blood pressure to return this valve back to normal
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lowering
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__in CO due to parasympathetic stimulation and inhibition of sympathetic activity
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decrease
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__ in resistance due to widespread vasodilation , due to inhibition of sympathetic reactivity , resulting in vasodilation of non essential blood vessels
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decrease
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if blood pressure falls below normal , the body responds by __ mean arterial pressure to return valve back to normal
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raising
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__in CO due to stimulation oof sypathetic innervation to the hearrt (increase in heart rate and strangth of heart contraction)
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increase
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__ in resistance due to widespread peripheal vasoconstriction due to stimulation of sympathetic activity (resulting in vasconstriction of non essentail blood vessels)
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increase
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provides a short and long term regulation of cardiovascular performance
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hormones and cardiovascular regulation
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__ __ produced by pituitary gland, responds to low BP caused by a dcrease in blood volume or increase in plasma osmotic pressure, target (blood vessels-peripheal vasconstriction, kidneys-conservation of water), result - increase in resistance & blood volume = increase in BP in order to restore normal blood pressure
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antidiuretic hormone
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all of these are:
antidiuretic hormone , epinephrine, aldosterone , angiontension II,erythroprotein, atrial natiuretic peptide |
hormones and cardiovascular regulation
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-- produced by adrenal glands --responds to "fight or flight" -- targets (blood vessel- peripheal vasconstriction to non essentail blood vessels)--result (increase in resistance & thereforse an increase in BP in order to restore normal BP)
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epinephrine
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--produced by the adrenal gland-- responds to slow sodium ion levels and high potassium ion levels -- targets( kidney-conserve sodium ; release potassium ) -- result ( sodium rentenion results in water retention and therefore an increase in BP in order to restore normal BP
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aldosterone
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an enzyme produced by the kidney,,, it initiates the formation of angiotensinogen that is circulating in blood to become an active hormone , angiotension II
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renin
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--angiotensinogen circulates in blood to become this -- responds to low BP in the kidney --targets (blood vessels-peripheal vasoconstricition resulting in resistance, endocrine glands - cause the release of aldosterone & ADH which both causes a retention of water at the kidneys, brain centers- stimulates thirst to increase water comption) --result ( increase resistance & blood volume & increase in BP to restore normal BP)
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angiotension II
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-- produced by cells of the kidney -- responds to low BP within blood entering into the kidney or low oxygen livels in arterial blood entering into the kidney -- targets (red bone marrow-- stimulates erythropoeisis[RBC formation] ) -- result ( increase in blood volume & increase in BP to restore normal BP
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erythropoietin
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--produced by cardiac muscle cells in the wall of the right atrium -- responds toexcessive stretching of the right atrium during diastole. this occurs during elevated BP. -- targets ( kidney- stimulates the realease sodium into urine & promote the loss of water due to osmosis into the urine .. brain centers- inhibits thirst centers to cause a decrease in thirst and decrease consumption of water , endocrine glands- inhibits the release of aldosterone antidiuretic hormone (ADH) & epinephrine, peripheal blood vessels- stimulate vasodilation ) --result- decrease in blood volume & decrease in vascular resistance = decrease in BP to restore to normal BP
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atrial natriuretic peptide (ANP)
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-- extensive vasodilation occurs : skeletal muscle oxygen consumption increase . peripheal resistance drops , blood flow through the capillaries increases and blood enters the venous sytem faster
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light excercise
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the venous return increase: due to skeletal contractions and the respiratory pump
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light excercise
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cardiac output rises: due to increase in venuous return ( starling responsse to heart) CO keeps up witht he demand of the tissue for oxygen and BP is mantained.
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light excercise
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cardiac output cannot keep up with oxygen demand of skeletal muscles. there is a massive sypathetic stimulation -- with increase HR & constricition of blood flow to non essentail organs . blood is literally racing from the skeletal muscles to the heart and lungs and then reutrns back to the muscles demanding oxygen . (only the brain maintains its normal blood flow ) CO can increase from the resting average of 5-6 L / minute to 20-25 L/ miontue
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heavy excercise
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__ involves adjusting to the loss of blood
--neural response- baroreceptor reflex in response to low BP due to loss of blood volume --endocrine response- release of ADH, epinephrine, angiotension II --the body is stimulated to increase CO & increase resistance --result is the increase in MAP |
short term effects to hemorrhaging
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invovles restoring blood volume
--endocrine response- release of ADH ,aldosterone, angiotension II for water and sodium conservation. release of erythropoietein : replace RBC --result in the increase in MAP |
long term effects to hemorrhaging
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--abnormal accumulation of fluid in the interstitial fluids
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edema
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a thickening and toughening of the arterial walls
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arterioschlerosis
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abnormally high BP ; 150 /90 in adults
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hypertension
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--blood pressure low enough to interfere with circulation to vital organs
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hypotension
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--acute circulatory crisis marked by hypotension and inadequate peripheral blood flow
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shock
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-- is due to any condition in which blood vessels are inadequately filled and blood cannot circulate normally
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shock
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--body is able to correct hypotension by neural and endocrine mechanisms
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non progressive shock
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-- shock has not caused irreversible damage, but the situation gets progressively worse unless therre is medical intervention
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progressive shock
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-- most common type of shock
--results from large scale loss of blood due to acute hemorrhage, sever vomiting or diarhea, or extensive burns |
hypovolemic shock
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-- blood volume is normal, but circulation is impaired due to extensive vasodilation
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vascular shock
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--- systematic allergic reaction with massive histamine release . (histamine caused vasodilation)
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anaphylactic shock
(type of vascular shock) |
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---- severe bacterial infection (some bacterial toxins are often potent vasodilators)
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septic shock
(type of vascular shock) |
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-- due to ineffeicent pumping by the heart
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cardiogenic shock
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blood vessel with fewest number in the body
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elastic artery
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capillaries have small pores in endothelium
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fenestrated capillaries
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force that pushes water molecules out of capillary is ?
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hydrostatic pressure
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at the end of a capillary bed, fluid will tend to move __
at the veuous end , fluid will tend to move __ |
out vessel , into vessel
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nervous system has __ effect
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immediate
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