Blood Vessels

function of arteries

take blood away from the heart

function of veins

take blood towards the heart

what are capillaries?

small blood vessels with intimate contact with tissues

3 layers of blood vessel walls

tunica intima

tunica media

tunica externa

tunica intima

contact with the lumen

consists of endothelium and basement membrane

tunica media

circular smooth muscle layer

mediates vasoconstriction and vasodilation

tunica externa

loose connective tissue

vaso vasorum supplies blood to blood vessels

what are elastic arteries?

thick walled arteries near the heart that can stretch to accommodate large volumes of blood coming from the heart

what do elastic arteries contain?

elastin

what do elastic arteries help with?

stretching/recoiling helps to keep blood flow continuous rather than pulsating with heart contractions

what are muscular arteries?

distal large arteries that deliver blood to body tissues

characteristics of muscular arteries

have the largest tunica media

active in vasoconstriction and vasodilation

what are arterioles?

smallest of the arteries

control blood flow to the capillaries

3 types of capillaries

continuous

fenestrated

sinusoid

continuous capillaries

least permeable and most common

fenestrated capillaries

have large fenestrations (pores)

occur in places of active filtration

sinusoid capillaries

most permeable

occur in limited locations of liver, bone marrow, spleen

what is a capillary bed?

interweaving network of capillaries

what is microcirculation?

blood flow through a capillary

flow of blood through a capillary bed

arteriole → metarteriole → thoroughfare channel to the venule

what controls blood flow into capillary beds?

pre-capillary sphincters

what are venules?

smallest of veins

capillaries unite to form them

contain very little smooth muscle

venules join to form…

veins

characteristics of veins

tunics are highly reduced

tunica media is poorly developed

large lumina allow for accumulation of blood (called blood reservoirs)

venous valves

most veins work against gravity

without large tunica media, venous pressure is low

valves prevent backflow

anastomoses

connections between two tubular structures in the body

common in cardiovascular system

most are in capillary beds

many are in venous system

flow of blood through the fish

artium

ventricle

bulbus arteriosus

afferent brachial arteries

efferent brachial arteries

dorsal aorta

body

capillaries

sinus venosus

flow of blood through amphibian

anterior/posterior vena cava

sinus venosus

RA

ventricle

L truncus arteriosus

pulmocutaneous artery

lungs

integument

pulmonary veins

LA

ventricle

R truncus arteriosus

common carotid artery

internal/ external carotid artery

systemic arch

dorsal aorta

common iliac artery

femoral/sciatic artery

body

what does the truncus arteriosus split into?

L pulmocutaneous artery

R common carotid artery

the truncus arteriosus contains what structure?

spiral valve

function of spiral valve

opens/closes division in truncus arteriosus based on BP

open spiral valve blood flow

pulmocutaneous

more deoxygenated blood → to branchial (gill) arteries

closed spiral valve

systemic arch

more oxygenated blood → to systemic arteries

what taxa has a 3 chambered, 2 circuit system?

amphibian

where does the brachiocephalic trunk go to?

R subclavian artery

axillary artery

brachial artery

where does the common carotid artery go to?

head

where does the L subclavian artery go to?

axillary artery

brachial artery

path of thoracic aorta

abdominal aorta

external iliac artery

body tissues