Online HW blood vessels
anaphylactic shock
results from exposure to an antigen to which a person is allergic
neurogenic shock
form of venous pooling shock that results from a sudden loss of vasomotor tone
Action potentials are conducted from the baroreceptors to the brain via which nerve?
glossopharyngeal nerve
conditions that would decrease blood flow:
increasing blood viscosity increasing red blood cell count increasing vessel length dehydration vasoconstriction increased resistance
conditions that would increase blood flow:
increasing vessel radius increasing blood pressure increasing blood velocity aldosterone hypersecretion
what is the simplest and most common route for blood to travel?
heart ---> arteries-----> arterioles ----> capillaries ----> venules ----> veins. The blood passes through only one network of capillaries from the time it leaves the heart till the time it returns
where are baroreceptors found?
in the carotid sinuses
hypovolemic shock
produced by a loss of blood volume as a result of hemmorage, trauma, ect.
accurate statements regarding the effects of edema
- Cerebral edema can produce headaches, nausea, and sometimes delirium, seizures, and coma. - As the tissues become congested with fluid, oxygen delivery and waste removal are impaired and the tissues may begin to die. - Pulmonary edema presents a threat of suffocation as fluid replaces air in the lungs.
what is venous anastomosis?
- Most common - One vein empties directly into another - Reason vein blockage is less serious than arterial blockage
what is arterial anastomosis?
- Two arteries merge - Provides collateral (alternative) routes of blood supply to a tissue - Coronary circulation and common around joints
what is arteriovenous anastomosis?
Artery flows directly into vein, bypassing capillaries
what is the circulatory route with the portal system?
Blood flows through two consecutive capillary networks before returning to heart • Between hypothalamus and anterior pituitary • In kidneys • Between intestines to liver
What does decompensated shock result in?
Ischemia and acidosis of the brainstem, myocardial ischemia, several life-threatening positive feedback loops, and disseminated intravascular coagulation
continuous capillaries
Occur in most tissues • Endothelial cells have tight junctions forming a continuous tube with intercellular clefts • Allow passage of solutes such as glucose • Pericytes wrap around the capillaries and contain the same contractile protein as muscle - Contract and regulate blood flow
What is(are) the physiological purposes of vasoreflexes?
To cause a generalized raising or lowering of blood pressure throughout the body and to selectively modify the perfusion of a particular organ by rerouting blood from one region of the body to another
circulatory shock
any state in which cardiac output is insufficient to meet the body's metabolic needs
do veins or arteries have profuse elastic fibers in the tunica media?
arteries
do veins or arteries have relatively thicker walls?
arteries
do veins or arteries have thick layers of smooth muscle?
arteries
which do the arteries and veins each use? convergence or divergence
arteries: divergence veins: convergence
Just prior to entering capillary beds, what becomes extremely thin and present only a few layers of smooth muscle?
arterioles
what are the three types of anastomosis?
arteriovenous anastomosis venous anastomosis arterial anastomosis
The site of gaseous exchange, or_________, are characterized by extremely thin walls with only endothelium and basal lamina, which better suits diffusional requirements.
capillaries
capillary beds have precapillary sphincters at the junction of
capillaries and metarteriole
What forces favor capillary filtration?
capillary filtration occurs at the arterial end and is forced by the glomeruli
What forces favor reabsorption?
capillary reabsorption occurs that the venous end and is forced by the alveolar capillary
cardiogenic shock
caused by inadequate pumping of the heart
what are the three types of capillaries?
continuous capillaries fenestrated capillaries sinusoids
what is anastomosis?
convergence point between two vessels other than capillaries
During exercise the skeletal muscles receive more or less blood flow?
more
fenestrated capillaries
occurs in the kidneys, small intestine • Organs that require rapid absorption or filtration • Endothelial cells riddled with holes called filtration pores (fenestrations) - Spanned by very thin glycoprotein layer - Allow passage of only small molecules
sinusoids (discontinuous capillaries)
occurs in the liver, bone marrow, and spleen • Irregular blood-filled spaces with large fenestrations • Allow proteins (albumin), clotting factors, and new blood cells to enter the circulation
obstructed venous return shock
occurs when an object compresses a vein and impedes its blood flow
septic shock
occurs when bacterial toxins trigger vasodilation and increased capillary permeability
low venous return shock
occurs when cardiac output is low because too little blood is returning to the heart
What is the main chemical stimulus for cerebral autoregulation?
pH
In what conspicuous way does perfusion of the brain differ from perfusion of the skeletal muscles?
perfusion of the brain is more continuous while perfusion of the skeletal muscles is discontinous.
what is the first vessel blood enters upon exiting the heart?
the aorta
Most of the redirection will occur in what?
the arterioles
After a meal, what receives priority? and the skeletal muscles receive very little flow
the intestines
what expands and recoils with every heart beat due to a histologically dominant network of elastic tissue in the tunica media?
the large (elastic) arteries
what contains abundant but irregularly spaced smooth muscle with frequent valves present in the tunica interna?
the medium veins
what is an example of a large vein that includes smooth muscle circularly and longitudinally arranged in the tunica media and externa, respectively?
the superior vena cava
When a person is still, blood accumulates in the limbs because venous pressure is not high enough to override the weight of the blood and drive it upward. true or false?
true
The action potential from the brain to the heart travels along which nerve(s)?
vagus nerve
do veins or arteries contain valves?
veins
do veins or arteries have a larger diameter?
veins
do veins or arteries have a larger lumen?
veins
do veins or arteries have sites used for blood location?
veins
do veins or arteries have superficial locations?
veins
After exiting the capillary, what contains no muscle and is the first vessel that blood enters on its way back to the heart?
venules
Blood flow is redirected according to metabolic needs?
yes
Constriction of these sphincters reduces the blood flow through their respective capillaries?
yes
When the sphincters are open, blood will fill the capillary bed?
yes
When this occurs, blood is diverted to tissue or organs elsewhere?
yes