mass transport in animals Flashcards
why is a mass transport system needed in larger organism
most cells are too far away from exchange surfaces for diffusion alone to maintain composition of tissue fluid within suitable metabolic range
mass transport maintains final diffusion gradients bringing substances to and from cells
helps maintain relatively stable immediate environment of cells that is tissue fluid
draw the circulatory system
left side deoxygenated blood
kidneys to renal vein to vena cava entering heart to pulmonary artery from heart to lungs to be oxygenated
right side oxygenated blood
pulmonary vein from lungs to heart
aorta out of heart
renal artery to kidney
why is the human a closed double circular system
prevents mixing of oxygenated and deoxygenated blood so blood pumped to body is fully saturated with oxygen so efficient delivery of oxygen and glucose for respiration
blood can be pumped at higher pressure so substances taken to and removed from body cells quicker and more efficiently
describe the two circuits of the circulatory system
pulmonary circulation
- deoxygenated blood in right side of heart pumped to lungs
- oxygenated blood returns to left side
systematic circulation
- oxygenated blood in left side of heart pumped to tissues and organs
- deoxygenated blood returns to right side
what is the purpose of the coronary arteries
deliver oxygenated blood to cardiac muscle
describe the blood vessels entering and leaving lungs
aorta - takes oxygenated blood from heart to respiring tissues
vena cava - takes deoxygenated blood from respiring tissues to heart
pulmonary artery - takes deoxygenated blood from heart to lungs
pulmonary vein - takes oxygenated blood from lungs to heart
describe the blood vessels entering and leaving kidneys
renal arteries - take oxygenated blood to kidneys
renal veins - take deoxygenated blood to vena cava from kidneys
draw the human heart
right deoxygenated side
vena cava —> right atrium—> right ventricle —> pulmonary artery
left oxygenated side
pulmonary vein —> left atrium —> left ventricle —> aorta
semi lunar valves in pulmonary artery and aorta
atrioventricular valves in atriums
how does the structure of the heart relate to its function
atrioventricular valves - prevent back flow of blood from ventricles to atria
semi lunar valves - prevent back flow of blood from arteries to ventricles
left has thicker muscular wall - generates higher blood pressure for oxygenated blood to travel greater distance around body
right has thinner muscular wall - generates lower blood pressure for deoxygenated blood to travel small distance to lungs higher pressure would damage alveoli
describe the structure of the arteries and how it relates to its function
carry blood from heart to rest of body at high pressure
thick smooth muscle layer
- contact pushing blood along
- contain blood flow and pressure
elastic tissue layer
- stretch as ventricle contacts and recoil as ventricle relaxed
- reduces pressure surges and maintain high pressure
smooth and thin endothelium
- reduces friction
narrow lumen
- increases and maintains high blood pressure
describe the structure of the arterioles and how it relates to it function
division of arteries to smaller vessels which can direct blood to different capillaries
similar to arteries but
tinker muscle layer
- constricts to reduce blood blood by narrowing linen
- dilates to increase blood flow by enlarging lumen
thinner elastic layers as lower pressure surges
describe the structure of veins and how it relates to its function
carry blood back to heart under low pressure
wider linen than arteries
very little elastic and muscle tissue
valves
- prevent back flow
contraction of skeletal muscles squeezes veins maintaining blood flow
describe the structure of capillaries and function
capillaries allow the efficient exchange of gases and nutrients between blood and tissue fluid
wall is thin layer for short diffusion path
capillary bed is made up of large network of beaches capillaries so increased surface area for diffusion
narrow lumen reducing flow rate so more time for exchange
no cell is far away from capillary short diffusion path
pores in walls between cells allows substances to escape
what is tissue fluid
the fluid surrounding cells
provides respiring cells with water oxygen glucose amino acids
enables waste substance to move back into blood eg. urea carbon dioxide lactic acid
describe the formation of tissue fluid
higher hydrostatic pressure inside capillaries than tissue fluid
forces fluid out of capillaries
large plasma proteins remain in capillaries
describe the return of tissue fluid to circulatory system
hydrostatic pressure reduces as fluids leave capillaries
due to water loss an increasing conc. of plasma proteins lowers the water potential in capillary below tissue fluid
water re enters the capillaries by osmosis down water potential gradient
excess water taken up by lymph system and returned to circulatory system
what may the causes of tissue fluid accumulation be
low conc. of protein in blood plasma
water potential in capillaries not as low so potential gradient reduced
more tissue fluid formed at arteriolar end
less water absorbed into capillary by osmosis
high blood pressure
high hydrostatic pressure
increased outward pressure at from arterial end reduces inward pressure at venal end
so more tissue fluid formed
lymph system not able to drain fast enough
describe the pressure and volume changes associated with valve movement during the cardiac cycle
Atrial systole
- Atria contract→decreasing volume and increasing pressure inside atria
- Atrioventricular valves forced open
- When pressure inside atria > pressure inside ventricles, atrioventricular valves open
- Blood pushed into ventricles
- (note: semilunar valves are shut)
Ventricular systole
- Ventricles contract from the bottom up → decreasing volume and increasing pressure inside ventricles
- Semilunar valves forced open
- When pressure inside ventricles > pressure inside arteries
- Atrioventricular valves shut
- When pressure inside ventricles > pressure inside atria
- Blood pushed out of heart through arteries
Diastole
- Atria and ventricles relax→increasing volume and decreasing pressure inside chambers
- Blood from veins fills atria (increasing pressure inside atria slightly) and flows passively to
ventricles
- Atrioventricular valves open
- When pressure inside atria > pressure inside ventricles blood flows passively to ventricles
Semilunar valves shut
- When pressure inside arteries > pressure inside ventricles
- Note: the purpose of valves shutting is to prevent back flow into (named chamber / vein) to maintain unidirectional flow of blood through the heart
how to work out cardiac output and what is it
stoke volume x heart rate
cardiac output - amount of blood pumped out the heart per minute
stroke volume - volume of blood pumped by ventricles in each heart beat
heart rate - number of beats per min
how to calculate heart rate from cardiac cycle
one beat = one cardiacs cycle
find the length of one cardiac cycle
heart rate per min = 60/ length of one cardiac cycle in second s
when are the semilunar valves closed
when pressure in aorta/ pulmonary artery is higher than ventricle —> prevents backflips of blood from arteries to ventricles
when are semilunar valves open
when pressure in ventricles is higher than in aorta/pulmonary artery -> blood flows from ventricle to aorta
when are atrioventricular valve closed
when pressure in atrium is higher than ventricles —> prevents back flow of blood from ventricle to aorta
when are atrioventricular valves open
when pressure higher in ventricle than atrium —> blood flows from ventricle to atrium
