Facilitates exchange of materials, providing a rapid long-distance internal transport system that brings resources close enough to cells for diffusion to occur.
Circulating fluid is pumped through open-ended vessels and flows out among the cells. - Example: arthropods (most invertebrates)
Circulating fluid is confined to vessels and is distinct from the fluid found around cells (interstitial fluid). Example: Some invertebrates, vertebrates.
Open: Requires less energy in operation & maintenance and provides support during molting.
2. Closed: More efficient at moving materials in highly developed vertebrates.
Contains both the heart and blood vessels.
Atria - receive blood
Ventricles - pump blood
Arteries - carry blood from heart
Arterioles - connect arteries to capillaries
Capillaries - infiltrate every organ
Venules - connect capillaries to veins
Veins - carry blood to heart
Prevent backflow and keep blood moving in the correct direction.
Collect blood returning to heart and pump it into ventricles; Ventricles – pump blood.
1 complete cycle of pumping and filling
Systole = contraction
Diastole = relaxation
Heart rate = number of beats/minute (60 – 80)
Sets rate and timing at which all cardiac muscle cells contract. Located in wall of rt. atrium.
(AV) node – relay which in-sures ventricles contract after atria (0.1 sec). Located in wall btw. rt. atrium & rt. ventricle.
Hydrostatic pressure that blood exerts against the walls of vessels which propels blood.
*Much greater in arteries than veins
*Gravity affects bp in larger land animals
Humans: heart - head = 0.35m, 27 mm Hg
Giraffe: heart - head = 2.5 m, 250 mm Hg
Dinosaurs: heart - head = 10 m, 760 mm Hg
Rhythmic contractions of arteries caused by pressure of blood forced into arteries during systole.
Systole = contraction (120).
Diastole = relaxation (80).
Liquid matrix with cells in suspension (90% water; 55% of blood composition.
Plasma proteins – buffer, maintain osmotic balance, contribute to blood’s viscosity.
1. Fragments of cells (2 – 3 µm in diameter)
2. Lack nuclei.
3. Originate in bone marrow.
4. Function: Blood clotting.
Disorders of the heart and blood vessels.
1)Account for more than 50% of US deaths.
a) Genetic predisposition
b) Sedentary lifestyle
Death of nervous tissue in the brain due to blockage or rupture of arteries in the head.
Extensions or outfoldings of the body’s surface in aquatic animals.
Great amount of surface area
Can remove 80% of dissolved O2 in water
*Found in snails, spiders, and terrestrial vertebrates.