Slides in this set
blood, carried away from
the heart. Thick tunica
adventitia and more elastic
blood, carried to the heart.
Thinner tunica adventitia
and contain valves.
Name of layer Description
Capillaries small thin Tunica adventitia Outer layer of a vessel, contains
connective tissue and collagen.
vessels that exchange
Tunica media Middle layer of a vessel.
substances between veins Contains muscle and elastic
and arteries. Only one tissue.
endothelial layer thick. Tunica interna Inner layer of a vessel. Contains
endothelial cells.…read more
· Blood flows freely · Blood flows through vessels
· No vessels · Faster blood flow
· Haemocoels: blood filled spaces · Higher BP
· No risk of damaged vessels · Risk of vessel damage
· Blood passes once through the
heart for every supply to the · Blood passes through the heart
body twice for every supply to the
· BP is lowered, as it loses body
pressure in capillaries · Blood flows at a higher pressure
Single system Double system…read more
Diastole: Atrial systole: Ventricular systole:
· Blood fills the atria · Excitations cause atria to · Blood fills the ventricles
· SA node stimulates contract · Excitations travel down to
excitation of cardiac · Pushes the blood through cardiac muscles in
muscles AV valves into ventricles ventricles and ventricles
· AV valves open contract
· Blood is pushed through
semi lunar valves into
Blood and Blood Pressure
· The hydrostatic force of blood against the vessel walls
· Affected by cardiac output and peripheral resistance
· BP drops in capillaries due to blood draining out into lymphatic system and lower
Plasma Liquid component of blood. 90% water.
Erythrocytes RBCs. Carry oxygen. Biconcave discs
with no nucleus.
Leucocytes WBCs. Fight infection, release
antibodies, ingest pathogens.
Thrombocytes Platelets. Cell fragments. Involved in
clotting process, contains clotting