8!!! transport in mammals Flashcards
What correctly describes the path of blood in the systemic circulatory system?
aorta -> body tissues -> vena cava
path of deoxygenated blood in the systemic circulatory system
body tissues → vena cava → heart
double circ system
In a double circulatory system, the right side of the heart pumps deoxygenated blood to the lungs, while the left side of the heart pumps oxygenated blood to the body.
artery features
collagen outer
thick elastic, muscle layer
endothelium
lumen
artery adaptation- collagen
provides strength to prevent vessel from bursting+maintain vessel shape
artery adaptation- elastic fibres
contains elastin that lets them stretch+recoil to withstand pressure changes
artery adaptation- thick smooth muscle layer
contracts/relaxes to constrict/dilate lumen+control blood flow
Vasoconstriction
Smooth muscle contracts, constricting the blood vessel and decreasing blood flow
Vasodilation
Smooth muscle relaxes, dilating the blood vessel and increasing blood flow
adaptations of veins: collagen
Provides strength to prevent the vessel from bursting and maintain vessel shapeadaptations of veins
adaptations of veins- Little smooth muscle and elastic fibre
Not much is needed due to low blood pressure
thinner walls allow veins to be easily compressed, aiding the flow of blood
adaptations of veins- Valves
Pocket valves shut to prevent the backflow of blood when veins are squeezed by surrounding skeletal muscle
adaptations of capillaries- narrow lumen
allows RBC get close to body cells
adaptations of capillaries- highly branched
large SA for diffusion
importance of capillary beds as exchange surfaces
- substance exchange(glucose, O2) take place between blood and body tissues through diffusion
- capillaries found near alveoli in lungs. short diffusion pathway
- one cell thick
- creates a network in tissue to increase SA or exchange of metabolites and gases
RBCs
shape, organelles, size
binconcave, disc- increases area for O2 to bind, Hb molecules
no nucleus/mitochondria/ER only cytoplasm
7micrometres SO Hb near cell surface to quickly allow gas exchange to occur
flexible: can deform to pass through narrow capillaries
WBCs (leucocytes)
where made, types
short ans
made in bone marrow
T lymphocytes, B lymphocytes (produced in lymph nodes+spleen)
T produced+mature in thymus
diff between RBC and WBC
