Human Physiology Arteries and Arterioles (10-17-23)

myogenic tone

muscle tone in arterioles

myogenic tone local regulatory mechanisms (3)

active hyperemia, flow autoregulation, endothelial factors

myogenic tone extrinsic regulatory factors (2)

sympathetic neural control, hormones,

myogenic tone regulatory hormones (4)

epinephrine, angiotensin, vasopressin, atrial natriuretic hormone

active hyperemia

increased blood flow to active tissues

active hyperemia process

metabolic activity of tissue increases, oxygen in blood decreases, arterioles dilate in organ, increased blood flow

flow autoregulation

organ can control how much blood flow it gets

flow autoregulation process

arterial pressure decreases, blood flow decreases, oxygen decreases, arterioles dilate in organ, increase blood flow to normal

increased plasma epinephrine causes

vasodilation or vasoconstriction

increased norepinephrine in extracellular fluid caused

vasoconstriction

neurons that release nitric oxide cause

vasodilation

alpha receptors cause

vasoconstriction

beta 2 receptors cause

vasodilation

at rest sympathetic neurons have a ___ level of activity to alpha receptor

middle

increased signal in sympathetic neurons leads to

increase in norepinephrine concentration at alpha receptor and decrease in radius

decreased signal in sympathetic neurons leads to

decrease in norepinephrine concentration at alpha receptor and increase in radius

decrease in O2, increase in CO2, increase in H+, or increase in K+ causes

vasodilation

the brain and heart have ___ autoregulation

powerful

capillaries

site of exchange between the circulatory system and interstitial fluid

capillaries are made of ___ cell(s)

one endothelial

capillaries have the ___ velocity, and the ___ total cross sectional area

slowest, biggest

leaky junctions

connections between capillary endothelial cells that allow water to leak

fenestrated

big pores in capillaries

transcytosis

brings proteins and macromolecules across endothelium

bulk flow

movement of ions, water and solutes through leaky junctions and fenestrated pores

capillary hydrostatic pressure

pressure on walls of capillaries that causes ions and solutes to leave

blood colloid osmotic pressure

non penetrating solute (proteins) in capillary pulls in water

arterial end of capillary net filtration

10 mm Hg out

venous end of capillary net filtration

8 mm Hg in

blood pressure is less on the ___ end of the capillary because ___

venous, the capillary provides resistance

net filtration of fluid out of capillaries per day

3 liters

lymph

interstitial fluid that has been pulled into lymph vessel

endothelial flaps

pull interstitial fluid into lymph vessel

lymph capillaries (location)

intertwined with circulatory system capillaries

lymph flow

lymphatic vessels → lymph node → venous circulation

lymphatic system roles (4)

return fluid to cardiovascular system, clear proteins from interstitial fluid, absorb fat in intestines, immune system

edema

accumulation of fluid in interstitial fluid

edema causes (2)

lymphatic drainage is compromised, balance of capillary hydrostatic pressure and osmotic pressure is off

function of venules and veins

bring blood back to the heart

resistance in veins is

low

valves in veins

one-way, prevent backflow

skeletal muscle pump

skeletal muscles contract

respiratory pump

uses breathing to help bring blood back to heart

most of your blood is in the ___

systemic veins

veins ___ around blood volume because they do not have a lot of ___ or ___

collapse, smooth muscle, elastic tissue

you can increase cardiac output by increasing ___

venous return