body fluids and circulation Flashcards
(54 cards)
outer layer of blood vessels
tunica externa ; fibrous connective tissue and collagen fibres
middle layer of blood vessels
tunica media ; smooth muscles and elastic fibres
tunics interna/intima
lining of thin squamous epithelium,yellow elastin fibres
function lf arteries
distribute blood from heart to body
function of veins
carry blood from body into heart
where is tunics media thicker
arteries
where are walls of blood vessels thicker
arteries
do arteries have valves
no
why is the heart called myogenic
because activities of heart are regulated by specialised nodal tissue
function of medulla oblongata in nervous control of hert
can moderate cardiac unction through ANS ; sympathetic and parasympatheic nerves modify the rate of depolarization
function of sympathetic nerves in nervous control
nerve endings release noradrenaline which accelerates heart beat, strength of ventricular contraction, cardiac output
parasympatheic nerve function
erve endings release acetylcholine, decreases heart beat, speed of action potential conduction, cardiac output
how do adrenal medullary hormones increase cardiac output
by release of adrenaline and noradrenaline
what type of tissue is blood
specialized fluid connective tissue
how do sponges and coelentratstes circulate water
through body cavities
what does blood contain
plasma, fluid matrix, formed elements
describe plasma
straw Coloured, viscous fluid
composition of plasma
constitutes 55% of blood, 90-92% is water
percentage of proteins present in blood
6-8%
major proteins present in blood
fibrinogen, albumin, globulin
fibrinogen function
clotting factor
globulin
defence mechanisms of body
albumin
osmotic balance
plasma also contains
minerals like Na+,Ca2+,Mg2+,HCO3-,Cl-, glucose, amino acids, lipids
