Unit 3 Terms and Concepts

transmural pressure

pressure difference across a wall

varicose veins

enlarges, swollen, twisted superficial veins > weakened valved prevent blood flow, increasing pressure

venous hypertension

abnormally high venous pressure

venous reflux

backflow of blood, diminishes blood return

venous stasis ulcer

full thickness defect of skin, ankle region, venous insufficiency

venules

small veins, collect blood from capillaries

the venous system acts as a _____ to maintain homeostasis

reservoir

the venous system ________ ______________ blood back to the heart

returns deoxygenated

____ pressure in arterioles, _____ pressure in venules

high, low

capacitance

change in volume per change in time

compliance

change in volume per change in pressure

venous congestion compromises:

capacitance, compliance, and elasticity

veins are _______ vessels of the body

capacitance

venous system hold about ______ of total blood volume

2/3

distended vein diameters can be _______x larger than corresponding artery

3-4

veins can change

shape

shape/ diameter impacts

resistance

distended/ circular veins

low/ no resistance to flow

partially empty/ elliptical veins

increase resistance

hydrostatic pressure

related to the weight of a column of blood within the vessel

standing affects

overall venous pressure, increased pressure below the heart

exercise reduces

venous pressure and volume

dynamic pressure + hydrostatic pressure =

total pressure

below the RA standing

dynamic pressure + 2mmHg of hydrostatic pressure per inch

volume increase causes pressure

increase

venous flow moves, volume and pressure

decrease

high transmural pressure

distended vein

low transmural pressure

collapsed, elliptical vein

veins can ___ to accommodate more volume without increasing the pressure (to a point)

dilate

fully distended vein

more pressure required along the system to maintain gradient and move flow

RBC/fluid enter tissue then:

small % picked up by the venous side

lymphatic system picks up residual fluid/ waste

increase capillary pressure leads to

excess fluid into the tissue space - edema

edema is caused/ exacerbated by

standing, pregnancy, cardiopulmonary issues, failed venous valves, venous thrombosis

long standing edema can cause

tissue breakdown (ulcers)

how to reduce venous volume and pressure

positional changes, healthy respiration, exercise, healthy valves, healthy right heart function, compression stockings

during inspiration

diaphragm descends

chest cavity decreases pressure, increases venous flow to heart

abdomen increase pressure

IVC collapses and venous return from the legs is impaired

during expiration

diaphragm ascends

chest pressure increase, decreased venous return to heart

abdominal pressure decreases, ivc compression released, flow from legs moves into abdomen

thrombosis distal to occlusive dvt

increased resistance, volume, and pressure

waveforms do not change with respiration

venous _______ help reduce resistance, volume, and pressure

collaterals

exercise causes

arterioles vasodilate

capillaries move oxygenated RBC in, waste out

increase venous return and volume

calf muscle pump

pumps blood back to heart, reduces impact of hydrostatic pressure, relaxation - blood drawn into calf veins/ sinuses

venous valves

prevent retrograde venous flow/ reflus

closure helps reduce venous pressure

valvular insufficiency

damaged/ absent/ abnormally developed > retrograde flow

increased volume and pressure

calf pump cannot reduce volume/pressure

spider veins to ulcers

independent of other diseases

degeneration of venous valves/ walls - could be genetic

superficial veins

secondary valvular disorder

develops due to pathology

DVT, trauma, iliac vein compression, etc

deep, perforating, and superficial veins

congenital valvular disorder

present at childhood/ birth

absence or malformation

rare

normal venous flow

superficial to deep via junctions or perforator veins, toward heart with movement/ respiration

primary abnormal superficial venous valves

increased volume/ pressure in superficial venous system

varicose veins - dilated, elongated, tortuous

abnormal secondary superficial venous valves

result of damage to deep veinous valves, caused by DVT

retrograde deep venous flow

damages perforator valves

overloads SFV system

post thrombotic syndrome

fetus requires ______ maternal blood volume

increased

hormone changes during preganancy can cause

smooth muscle cell relaxation

increased vein diameter

slow venous flow

increased clotting factors (excess bleeding during delivery)

pregnancy can _______ risk of the development of varicose veins

increase due to

hereditary

increased parity

abnormal weight gain

>9 month pregnancy

pre-eclampsia