TEST 1: MICROCIRCULATION Flashcards
Blood vessels are divided into 3 layers called _____
Tunics
Outer most layer of the blood vessel
Tunica adventitia
Middle layer of the blood vessel is the tunica _______
Tunica Media
Inner most layer of the blood vessel is the Tunica ______
Tunica Intima
Large blood vessels need their own blood supply which is called what?
Vaso vasorum
Type of nerve that innervates the smooth muscle of blood vessels
Sympathetic nerve
Made up of connective tissue; anchors the blood vessel down
Tunica adventitia
These two things make up the tunica media
External elastic membrane
Smooth muscle
Allows BV to recoil to original state; keeps elastic/firm
External elastic membrane (of tunica media)
Smooth muscle of the tunica media is what gives the ability for the BV to _______ and _________.
Dilate and Constrict
More muscle = more ability to dilate/constrict
4 parts that make up the tunica intima
Internal elastic membrane
Lamina propria
Basement membrane
Endothelium
Fxn of internal elastic membrane
Same as external, allows BC to recoil to original state
Smooth muscle and connective tissue layer of the tunica intima
Lamina propria
Provides support to the inner most layer of the tunica intima, the endothelium.
Basement membrane
Layer of the BV in direct contact with the blood
Endothelium
Two basic types of arteries
Large elastic artery
Muscular artery
This type of artery is composed mostly of (tunica media) elastic tissue to allow recoil when stretched
Large elastic artery
This type of artery has a very thick tunica media layer of smooth muscle so it can dilate and constrict; control blood flow
Muscular artery
Veins tend to be _______ than arteries
Thinner
Veins do have some ________ so they can dilate and constrict, but not as much as arteries
Smooth muscle
Veins have ______ that allow for one way flow to propel blood back to the heart
Valves
Large arteries > medium arteries > smallarteries > arterioles > _________ >__________
Metarterioles
Capillaries
Known as “exchange vessels”; very well adapted for exchange of O2, nutrients, and fluid.
Capillaries
Capillaries are composed of a _______ and endothelial cells; provides structure.
Basement membrane
Capillaries have a very small diameter; so _______ have to line up to pass through
RBC’s
________ of RBC to enter capillary favors release of O2 to interstitial and cells; reason why they need to be a certain shape and pliable.
Compression
Arterioles turn into metarterioles, which turn into what?
Capillary network
This allows for unobstructed blood flow all the way from the arterial end of the capillary network, to the venous end.
Thoroughfare channels
Bands of smooth muscle wrapped around capillaries; used to constrict/dilate to regulate bloodflow through capillary network
Precapillary sphincter
What determines whether the precapillary sphincter constricts or dilates?
The O2 demand of the tissue supplied by the capillary network
If tissue supplied by a capillary network is in highly metabolic, large O2 demand, the precapillary sphincters will CONSTRICT/RELAX.
RELAX
What is the point of relaxation of precapillary sphincters when O2 demand etc is high?
Allows more blood flow and more O2/nutrients are delivered to the tissue
If tissue supplied by network is not very metabolic, not requiring much O2, precapillary sphincters will CONSTRICT/DILATE.
CONSTRICT
What happens when precapillary sphincters are constricted to the tissue they supply?
Blood is shunted elsewhere where it is needed more.
What are some vasodilators that cause precapillary sphincters to relax
CO2 Lactate Histamine Adenosine K+ H+ Decreased pH Decreased glucose in tissues Nitric oxide Etc
Blood pressure decreased as it moves throughout the vascular system. TRUE/FALSE.
TRUE
Decreasing blood pressure throughout the vascular system allows for ________ blood flow, down a pressure gradient.
One way
There is no systolic or diastolic pressure beyond the _________ level; one pressure, one number.
Capillary
As blood approaches the heart via the vena cava; pressure approaches ______.
Zero
Objective of the arterial end of the capillary is _________; movement of fluid from capillary to interstitium.
Filtration
There are ____ pressures that favor/oppose filtration.
4
Pressure fluid is placing on the walls of the capillary.
Capillary Hydrostatic Pressure (CHP)
CHP favors ________.
Filtration
Negative interstitial fluid pressure favors ________ of fluid from the capillary to the _________.
Filtration
Interstitium
Negative IFP is caused by what?
Terminal lymphatic vessels
Terminal lymphatic vessels sit right outside of capillaries and transport fluid from the lymphatic system to the _______ veins and eventually back to circulation.
Subclavian veins
Plasma colloid osmotic pressure (PCOP) ________ filtration; composed of proteins, primarily ______; favors holding fluid in the _______.
OPPOSES filtration
Albumin
Capillary
The proteins present in the interstitial fluid account for this pressure
Interstitial fluid colloid osmotic pressure (IFCOP)
Under normal conditions, proteins are too large to move across pores in capillaries, so they stay in the vascular system; but some do get to the interstitial compartment. TRUE/FALSE
TRUE
Interstitial fluid colloid osmotic pressure IFCOP favors _________.
Filtration
How to calculate net arterial FILTRATION pressure
Outward minus inward
CHP+ -IFP+ IFCOP) - (PCOP
Objective at the venous end of the capillary is _________ of fluid back into capillary.
Reabsorption
Capillary hydrostatic pressure CHP will INCREASE/DECREASE at the venous end of the capillary.
Why?
DECREASE
Fluid was filtered out on the arterial end
How to calculate net venous reabsorption pressure
Inward minus outward
PCOP - (CHP+-IFP+IFCOP)
What prevents accumulation of fluid in the interstitium when net filtration pressure is greater than reabsorption pressure?
Terminal lymphatic vessels
What are 3 things that could increase CHP?
Increased blood pressure
Increased vascular volume
HF/increased CVP
Increased CHP at the arterial side favors _______
Filtration
Increased CHP on the venous side of the capillary bed opposes ________
Reabsorption
The net effect of increased CHP is what 2 things?
Interstitial edema
Decreased vascular volume
In what condition is increased CHP and interstitial edema a compensatory mechanism to decrease vascular volume
HF
What might cause decreased CHP? (2)
Decreased BP
Decreased vascular volume
Decreased CHP at the arterial side of the capillary opposes ________; at the venous side, it favors _______.
Opposes filtration
Favors reabsorption
Net effect of decreased CHP
More volume stays in the systemic circulation
What can cause decreased PCOP
Hypoalbuminemia
What are two things that can cause hypoalbuminemia?
Malnutrition
Liver disease
Decreased PCOP favors ___________ at the arterial end and opposes _________ at the venous end.
Favors filtration
Opposes reabsorption
Net effect of decreased PCOP
Interstitial edema
Decreased vascular volume
Leaky capillaries and loss of albumin to interstitial fluid increases _________ pressure.
IFCOP
What are 3 possible causes of increased IFCOP; cause increased capillary permeability
Sepsis
Traumatic injury
Severe burns
Increased IFCOP at the arterial side of the capillary favors _______ ; opposes _________ at the venous end
Favors filtration
Opposes reabsorption
Net effect of increased IFCOP
Interstitial edema
Decreased vascular volume
To treat increased IFCOP; your should give albumin. TRUE/FALSE
FALSE
Need to wait until inflammatory response comes down, then can give albumin
What could cause lymphatic obstruction?
Central line
Tumor
Cancer
Lymphadenectomy
Lymphatic obstruction allows for accumulation of ___________ in the interstitial space bc dont have terminal lymphatics sucking up fluid.
Albumin (and fluid)
