B L O O D V E S S E L S Flashcards
tunica interna
endothelium, simple squamous, decrease friction
tunica media
smooth muscle (elastin), vasomotor nerve fibers, bulkiest layer
tunica externa
collagen fibers, protection and contains vessels
arteries details
compared to veins:
- thicker walls
- more smooth muscle
- more elastin fibers
- more resilient
- more muscular
veins details
compared to arteries:
- thinner walls
- less smooth muscle
- less elastic fibers
- less muscular
which blood vessels are located at the end of a capillary bed?
arterioles before
venues after
which vessels hold the largest percentage of our blood supply?
veins
what is the relationship of blood flow to resistance?
inversely proportional
what happens to blood pressure as blood travels from arteries to veins?
decreases as it gets away from the heart with a steep drop happening in the arterioles
how would dilation of arterioles affect blood flow to the tissues?
increase blood flow
how does the PNS affect BP?
decreased BP
inhibit SNS
how does the SNS affect BP?
increased BP, NE, & EP to:
increase CO &
increase vasoconstriction
define NFP and describe the 4 pressures that contribute to it
NFP: factors promoting filtration (HPc +OPif) - factors promoting reabsorption (HPif + OPc)
(+) filtration
(-) reabsorption
- hydrostatic pressure & filtration are greatest on arteriole end
- osmotic pressure & reabsorption on venue end
beginning with the release of a kidney hormone, fully describe the process resulting in the activation of angiotensin 2
- secrete renin
- renin cleaves angiotensin to form angiotensin 1
- angiotensin 1 cleaved by ACE to generate angiotensin 2
- increase BP and increase CO by vasoconstriction, EPO, aldosterone, & ADH
how does the the hormone ANP (Atrial Natriuretic Peptide) influence our blood volume and pressure?
- decreased BP & BV by increased Na+ excretion
- increased urine output
- vasodilation
- block ADH, Ald, EP, & NE
how does the the hormone ADH influence our blood volume and pressure?
- increased BP & BV by increased water retention
how does the the hormone aldosterone influence our blood volume and pressure?
- increased BP & BV by increased water & Na+ reabsorption
how would increased hematocrit influence blood flow?
decrease blood flow
how would increased vessel diameter influence blood flow?
increase blood flow
fully describe the role of baroreceptors in regulation of HR and stroke volume
if BP high
- baroreceptors in carotid sinuses and aortic arch are stimulated
- increased impulses from baroreceptors
- stimulate cardioinhibitory
- inhibit cardioacceleratory
- inhibit vasomotor
- decreased vasomotor impulses allows vasodilation causing decreased resistance
- decreased sympathetic impulses to heart cause decreased resistance, decreased cardiac output, and decreased contractility
decreased cardiac output and decreased resistance lower BP to return it to its homeostatic range*
opposite for low BP*
which structure in the body divides the aorta into thoracic and abdominal aorta?
diaphragm
capillary bed
network of capillaries between arterioles and venules
microcirculation
blood flow through bed
vascular shunt
channel that connect arteriole directly to venule (metarteriole thoroughfare channel)
true capillaries
actual vessels involved in exchange
precapillary sphincters
regulate blood flow into true capillaries
- blood may go into true capillaries or shunt
- regulated by local chemical conditions (gas need of oxygen) & vasomotor nerves
capillary bed pathway
- terminal arteriole
- met arteriole thoroughfare channel
- post capillary venule
describe the pulmonary circuit carrying blood to and from the lungs
short pathway
arteries and arterioles more like veins and venules because resistance and pressure is low
auto regulatory mechanism
low O2 levels cause vasoconstriction
high O2 levels cause vasodilation to allow blood flow to O2 rich areas of the lungs
how is the blood flow in the abdominal viscera and the skin affected by exercise?
blood is shunted away from those areas to feed the muscles
what does the term “total peripheral resistance” refer to?
systemic opposition to flow
formation of fatty plaques in the walls of arteries is characteristic of what disorder?
artherosclerosis
