Chap8 Transport In Animals Flashcards
Vena cava
Carries blood into right atrium of heart
Pathway of blood from lungs to the heart
Lungs -> pulmonary vein -> left atrium -> left ventricle -> aorta
What controls heartbeat?
Pacemaker
Describe open circulation
Blood enters and circulates between tissues (interstitial spaces)
Direct material exchange between cells
Few blood vessels
Describe closed circulation
Blood remains inside blood vessel, never in direct contact with cells
Material enters/exits blood vessel through walls
Blood flows under high pressure
Blood vessels branched into capillaries
Describe single circulatory system Eg) fish
Blood in body brought by veins into heart
Heart pumps deoxygenated blood to gills
Blood becomes oxygenated and CO2 released
Oxygenated blood distributed by arteries around body
Capillaries deliver oxygen to tissues
Describe the two circuits of double circulatory system
Pulmonary circulation: deoxygenated blood travels from heart to lungs where it is oxygenated and then teturns to heart
Systematic circulation: oxygenated blood travels from heart to whole body and back to heart
Capillaries
Tiny blood vessels linking arterioles to venules
Veins
Carry blood back to heart under low pressure
Arteries
Carry blood away from heart under high pressure
Arterioles
Control blood flow from arteries to capillaries
Feature of arterioles
Thin muscle layer less elastic tissue
Venules
Capillaries connect to venules
Feature of venules
Thin walls
Features of arteries
Thick muscular wall for high pressure
Collagen layer for structural support
Elastic tissue provides flexibility
Impermeable
Features of veins
Thin muscular wall
Little elastic tissue
Collagen layer does NOT constrict
Impermeable
Valves
Features of capillaries
No muscle
No elastic tissue
No collagen
Not capable of constriction
Permeable
Tunica externa
Collagen fibres
Tunica media
Elastic fibres
Tunica intima (endothelium)
Single layer of cells in capillaries
Blood
Transport medium
Defends body against disease
Maintain diffusion gradient
Distributes heat around body