anatomy and physiology II chapter 20

Blood vessels form a _______ transport system

closed

Blood moves in a cycle: Heart → ______ → _______ → Capillaries → ______ → Veins → _____

arteries; arterioles; venules; heart

Vessels differ in _________, but all serve the same goal: ______ & ______ blood efficiently

structure; deliver; return

carry blood away from the heart

arteries

return blood to the heart

veins

thin vessels where exchange of gases, nutrients, and wastes occurs

capillaries

what circuit goes from the right side of the heart → Lungs → Back to left side?

pulmonary circuit

function of the pulmonary circuit

exchange CO2 for O2

what circuit goes from the left side of the heart → Body tissues → Back to right side?

systemic circuit

function of systemic circuit

deliver O₂ and nutrients; remove wastes

arteries ________ transport oxygen-____ blood

usually; rich

in arteries, ____ pressure, _______ lumen (opening)

high; smaller

veins _________ carry oxygen-____ blood

usually; poor

in veins, ______ lumen and contain valves to prevent _______

larger; backflow

3 tunics of BV walls

intima, media, externa

tunica intima contain ___________ (smooth lining) + ____ connective tissue

endothelium; thin

tunica ______ reduces friction for blood flow

intima

tunica ______ lines the lumen (inside space of the vessel).

intima

tunica media contain _______ muscle + ______ fibers

smooth; elastic

tunica _______ allows vasoconstriction (narrowing) & vasodilation (widening)

media

tunica _____ are thicker in arteries

media

tunica externa contains connective tissue with _______ & ______ fibers

collagen; elastic

tunica ______ protects and anchors vessel to surrounding tissue

externa

Endothelium regulates exchange between _____ and _______

blood; tissues

exchange for food and oxygen: into _______

tissues

exchange for wastes and CO2: into _____

blood

vascular endothelium produces compounds that control: vasodilation/_____________, Inflammation, ____ formation (injury response), _______ muscle activity

vasoconstriction; clot; smooth

Small arteries; regulate flow to capillaries

arterioles

Small veins; return CO₂-rich blood

venules

Veins have low ________ → need help _________ blood to heart

pressure; returning

in veins, blood flows ________ gravity, aided by: _______ and _______ muscle contractions

against; valves; skeletal

______ lumen allows more blood flow at _____ pressure

large; lower

factors aiding venous return: ________ pump, _______ pump, and ____________

respiratory; muscular; vasoconstriction

respiratory pump: Breathing changes _____ pressure → pulls blood _______ the heart

chest; toward

Muscular Pump: ________ muscles contract → ______ (milking) veins and push blood forward.

skeletal; squeeze

vasoconstriction – Veins narrow under ___________ control → blood moves ______ toward the heart.

sympathetic; faster

blood flows because of pressure _________

gradients

venous return depends on: ___ and _______ _____ pressure

CVP; right atrial

pressure in the large veins near the heart.

central venous pressure

if atrial pressure rises too much (like in heart failure), venous return decreases.

right atrial pressure

_______ venous return → stretches atrial walls → supports ______ output (Frank–Starling law).

increased; cardiac

venous return is also influenced by blood _______

volume

_____ blood volume (hemorrhage, dehydration) = ____ venous return

low; low

____ blood volume (fluid overload, pregnancy) = ____ venous return

high; high