cardiovascular

lumen

hollow center where blood flows

tunica interna (endothelium)

inner most layer, contacts blood

tunica media

thickest layer, smooth muscle fibers & elastic fibers

tunica externa

outer coat, elastic & collagen fibers

arteries

carry blood away from heart

arterioles

are smallest branches of arteries

capillaries

are smallest blood vessels, location of exchanges between blood & interstitial fluid, chemicals and gases diffuse across walls

venules

collect blood from capillaries

veins

return blood to heart

vasoconstriction

decrease diameter of lumen by contracting smooth muscle

vasodilation

increase diameter of lumen by relaxing smooth muscle

elastic arteries (conducting)

largest diameter, walls can stretch to preserve pressure

pressure reservoir

elastic energy acts a pressure storage

muscular arteries (distributing)

medium-sized, contain more smooth muscle → greater vasoconstriction & vasodilatation to adjust blood flow

resistance

opposition to blood flow due to friction between blood & inner wall

microcirculation

found near almost every cell in the body, known as exchange vessels

capillary bed

10 to 100 capillaries in a network

metarteriole

vessel that emerges from arteriole

thoroughfare channel

distal end of metarteriole

precapillary sphincter

control blood flow through true capillary

continuous capillary

almost totally intact

fenestrated capillary

contains small pores in endothelial cells

sinusoid capillary

fairly porous

valves

flap like cusps, prevent back flow of blood

blood distribution

veins & venules - 64%

arteries & arterioles - 13%

pulmonary vessels (system) - 9%

heart - 7%

capillaries - 7%

about __% of blood is constantly moving materials in and out of blood and interstitial fluid

7%

diffusion

o2, co2, amino acids, hormones move by simple diffusion

transcytosis

large water soluble molecules (insulin, antibodies) are actively moved by the endothelial cells

bulk flow

large amount of material moves together from high pressure to low pressure

out

filtration, high capillary pressure, 24L daily

in

reabsorption, decreased capillary pressure, 21L daily

systolic blood pressure

is the highest pressure obtained in arteries during systole

diastolic blood pressure

is the lowest pressure obtained in arteries during diastole

size of the lumen

the smaller the lumen the greater the resistance

blood viscosity

the greater the viscosity, the greater the resistance

total blood vessel length

the longer the blood vessel the greater the resistance

venous return

is the volume of blood flowing back to the heart, uses the valves in veins to prevent back flow

skeletal muscle pump

using muscles of arms and legs to milk blood back into the heart

respiratory pump

during inhalation the diaphragm compresses abdominal veins, breathing out compresses thoracic veins

chemoreceptors

carotid bodies and aortic bodies monitor blood, respond to changes in chemical composition, particularly pH and dissolved gases

baroreceptors

stretch receptors in arterial walls respond to changes in blood pressure

proprioceptors

monitor joint movement

E & NE

increase rate & contraction

antidiuretic hormone (ADH)

reduces water loss at kidneys, increase volume & contraction

renin-angiotensin-aldosterone

thirst, increase volume & peripheral vasoconstriction

erythropoietin (EPO)

stimulates red blood cell production, increases volume

natriuretic peptides (ANP, BNP)

excessive diastolic stretching → lower blood volume and blood pressure

korotkoff sounds

sound made by turbulant blood flow

systolic/diastolic - normal

120/80

pulse pressure (systolic-diastolic)

120-80=40

pulse points

• carotid - neck

• femoral - upper thigh

• brachial - arm

• popliteal - behind knee

• radial - forearm

• dorsal pedis - dorsal/medial foot

hypovolemic shock

decrease in volume

ex. bleeding, sweating, vomiting, diarrhea,

cardiogenic shock

heart fails to pump

ex. MI, valve problems

vascular shock

severe drop in BP due to abnormal vasodilation

ex. head trauma

anaphylactic shock

severe allergic reaction

ex. bee sting

septic shock

bacteria toxins

obstructive shock

when circulation is blocked

ex. pulmonary embolism

signs & symptoms of shock

• pulse is weak & rapid

• skin is cool, pale, and clammy

• mental state is altered

• urine production is reduced

• patient is thirsty

• patient may have nausea

responses of shock

• activation of renin-angiotensin-aldosterone system

• secretion of ADH

• activate the sympathetics

• release local vasodilators

aneurysm

a bulge in an arterial wall, is caused by weak spot in elastic fibers, pressure may rupture vessel

claudication

defective circulation to the limbs

orthostatic hypotension

brief drop in BP

phlebitis

inflammation of vein, most common in leg

edema

abnormal increase in interstitial fluid

varicose veins

leaky venous valves allow blood to pool in veins

hypotension

abnormally low blood pressure

hypertension

abnormally high blood pressure (greater than 140/90)

superior mesenteric vein

drains part of stomach, small intestine, and part of large intestine

splenic vein

drains spleen, part of stomach, and pancreas

inferior mesenteric vein

drains part of large intestine

left & right gastric veins

drains part of stomach