BMS 420 Exam 2: Chapters 13-23

Hydrostatic pressure

driving force causing blood flow along vessels and return to heart drives fluid through the trans-capillary pores into interstitial fluid

How are proteins moves across vesicles and what kind of diffusion

endocytosis and facilitated diffusion

In laminar flow blood velocity

increases from vessel wall to center of vessel

What is the windkessel effect

pushing of blood forward (diastole) even when heart is not active, is the elastic reservoir, helps dampen the fluctuation in blood pressure over cardiac cycle, assists in the maintenance of organ perfusion during diastole

What is elasticity

recoil when stretched

Capillaries most permeable to least

sinusoid>fenestrated>continuous

Sinusoid capillaries characteristics

Large gaps incomplete and discontinuous highly permeable to proteins and water Found in: spleen, RBC, Bone marrow, liver

Lymphatics consist of

Left and right subclavian veins and lymph capillaries

what is the vasodilator in endothelial cells

NO, enos

vascular roles of the venous compartment

collection, capacitance, volume reservoir

types of capillaries

continuous, fenestrated, sinusoid

the combination of compliance and elasticity allows for

converting pulsatile flow from the heart to steady flow known as pulse dampening

Arteriolar dilation

decrease arterial pressure, increase downstream volume, increases capillary and venous pressure, increases hydrostatic pressure and filtration

a decrease in interaction with the vessel wall leads to

decreased friction and increased velocity

Pulse dampening is

diastolic runoff

What is Ficks law

diffusion rate of an individual substance between plasma and interstitial fluid

Two pathways of trans-capillary exchange

directly through capillary endothelial cells and through pores between capillary endothelial cells

While velocity decreases through system flow must be , why?

equal through each region, MAP influences resistance

Transportation of substances is known as

flow between capillary bed and 1 organ to another

what is one effect of endothelial cell damage/ dysfunction

flow dependent vasodilation

what is shear stress

fluid frictional force acting at the apical surface of endothelial cells, is unidirectional, initiates cell signaling pathways, changes vessel diameter and remodeling

Aortic pulse pressure characteristics

force generated by heart during systole, proportional to stroke volume, inversely proportional to compliance

An increased sympathetic activity in veins leads to

increased smooth muscle contraction, increased peripheral venous pressure, increased venous return, increased central venous pressure

increased velocity at the vessel wall

increases shear stress

what generates shear stress

interaction between blood and endothelial cells lining vessels

Lymphatics flow is affected by

interstitial pressure, contraction of lymphatic vessels, stretch induced contractions, external compression

What is turbulent flow

irregular streamlines, less forward flow, less efficient

Histamine, blood flow and pressure

is an allergic response, increased blood flow, increases pressure inside, increases vascular leakage of plasma proteins and increased oncotic pressure outside, overall increased net filtration rate

vessel properties of arteries and veins

large radius, have lower resistance to flow through vascular beds then arterioles

Capillaries characteristics

large surface area minimal diffusion distance thin walled blood flow controlled by pre capillary sphincters aka smooth muscle influenced by local metabolism (not 100% perfused) can be nutritional and non

arteries and veins contain (volume)

larger volume of blood than arterioles and capillaries

Arterioles are

largest vascular resistance

How are substances transported through cells (lipid soluble and small molecules)

lipid soluble through endothelial and small water soluble through pores

Having more elastin fibers means

little resistance to stretch

Arterial compliance and elasticity

lower compliance vs veins, allows for arteries to act as pressure reservoir, influences aortic pulse pressure

Venous elasticity

lower, requires skeletal muscle contraction or SANS stimulation to increase venous smooth muscle contraction aka tone, leads to increased venous return

age and cardiovascular disease does what to compliance

lowers compliance and increase pulse pressure, increase in smooth muscle and collagen, decreased elastin

what is the primary role of the cardiovascular system

maintain homeostasis, distribution and exchange

Net movement of fluid between blood and interstitial compartments are important for

maintaining circulating blood volume, interstinal fluid absorption, edema formation, saliva sweat and urine production

Correlations of histamine

malnutrition and nephrotic syndrome

vascular roles of the arterial compartment

pulse dampening, distribution, pressure reservoir

Starling's hypothesis with trans-capillary movement

relationship between factors influencing trans-capillary fluid movement

Fenestrated capillaries characteristics

small holes 10 times more permeable filtration of proteins are prevented by negative charges on endothelial cells proteins are mostly negatively charged Found in: glomerulus Exocrine glands Intestinal mucosa Choroid plexus

What is laminar flow

smooth flow, majority of flow in cardiovascular system, very efficient movement and transport

Trans-capillary flow

between plasma inside capillary to interstitial fluid outside across the capillary wall (endothelial cells)

Arterioles regulate

blood flow through an organ and blood pressure through vessels

Where does turbulent flow occur

branch points, vessel narrowing which leads to increased velocity

Where is the site of exchange

capillaries

What is compliance, equation

change of volume for a given change in pressure, V/P, stretch

endothelial cells detect

changes in blood blow due to changes in shear stress

Changes of radius and organs

changes in radius have less effect on flow through organs

Net filtration rate

(hrdrostaic pressure in-out)-(onconic pressure in-out)

lymphatics characteristics

1 way valves, similar to veins, fluid, maintenance of hydrostatic and oncotic pressure returns fluid and removes proteins

What is trans-capillary diffusion influenced by

Fick's law of diffusion

What can cause turbulent flow

atherosclerotic plaques

Is filtration or absorption faster

absorption

net movement into capillaries, out of

absorption and filtration

convective transport vis bulk flow

all constituents move together with flow of blood

Oncotic pressure

also known as colloid movement of water due to proteins presence balancing force for hydrostatic pressure

Standing up changes (CO, MAP)

and increase in volume and pressure, decreased cardiac output and MAP

What is the difference between systolic and diastolic pressures

aortic pulse pressure

what part of the heart has low compliance

arteries

Plasma proteins do what across exchangeable cells

generally cannot move across, creates plasma osmotic pressure

What does turbulent flow cause

generates sound, murmur

Elasticity of the arteries

high elasticity, allows arteries to act as pressure reservoir beat to beat

Having more smooth muscle and collagen

high resistance to stretch

high compliance

high volume low pressure, lots of elastin, not a lot of smooth muscle

Venous compliance

high, small changes in venous pressure lead to large changes in venous volume, volume reservoir

Net filtration rate is determined by

hydrostatic pressure and oncotic

When in the supine position what happens to venous compliance

hydrostatic pressure equalized

Standing up leads to pooling of blood where

in feet, increased volume

A decrease in capillary oncotic pressure results in a filtration rate

increase

Arteriolar constriction

increase arterial pressure, decrease downstream volume, decreases capillary and venous pressure, decreases hydrostatic pressure and increases reabsorption

More friction from turbulent flow leads to

increase resistance and increased shear stress

If more compliant, comparison to elasticity

more compliance does not mean more elasticity

Continuous capillaries characteristics

most abundant in skin, muscle, lung, nervous system (BBB), connective tissue trans-capillary diffusion O2 and CO2 hydrophillic solutes pass via intracellular clefts/ channels

What is osmotic pressure

movement of water between interstitial fluid and intracellular fluid compartment

If there is low volume and high pressure

not very compliant

What determines movement of water between intravascular and interstitial compartment

osmotic and hydrostatic pressure

Trans-capillary transport is mostly what diffusion

passive

Flow is equal to

pressure times solubility divided by molecular weight of solute times surface area/ thickness

what is more compliant than arteries, arterioles and capillaries

veins

what part of the heart has high compliance

veins and aorta

60-70 percent of blood rests in

veins and venules

shear stress is directionally proportional to

velocity

what in diverted in times of need

venous constriction, muscular activity and sympathetic nervous system

shear stress is indirectly proportional to

vessel radius

Pulse dampening is also known as

windkessel effect