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