concept 24 - BIO10008

what are the functions of animal circulatory systems

• transport oxygen blood nutrients Co2 and wastes around the body

• thermal regulation - to surface to maintain physiological temperatures

• transmission of force - locomotion/reproduction

describe and justify the components needed in a circulatory system in animals

muscular pump - provides force for the flow of circulating fluids

circulating fluid - transport material around the body, move nutrients, remove wastes and CO2

tubular vessel that forms a circuit - to transport as well

gas exchange - to meet the demonds of oxygen inside and getting rid of CO2

compare open and closed circulatory systems

open circulatory system

• dump their interstitual fluids in the body cavity - named hemolymph

• low pressure in the blood flow, thus it is very slow flow

• cannot dilate to control blood flow

closed circulatory system

• interstitual fluids is different than circulating fluid - blood plasma

• high pressure in blood flow due to closed vessel leading to very high rapid flow

• allow to dilate to control blood flow, for example if there was a injury the vessels would dilate to allow more blood to clot

summarise the general trend of structural changes between the closed circulatory systems in fish, amphibians, reptiles and mammals

increased separation between blood flowing to the gas exchange organs and blood that flow to the body, fish is the oldest

what is the pathway oxygen takes in human circulatory system

lungs → alveoli (airsac) → capillaries → red blood cells → tissues

blood levaing the systemic circuit → right atrium → right ventricle → pulmonary artery to lungs → pulmonary vein → left atrium → left ventricle → major artery → aortra → body oxygenated

identify and describe the three circuits of the mammalian circulatory system

pulmonary circuit - lung

systemic circuit - body

coronary circuit - heart

artery

blood vessels that carry oxygen rich blood from heart to body’s tissue + organ

arteriole

away from the heart, connectors between arteries and capillaries, small blood vessels

capillary

in between arteriole and venule to facilitate exchange of substance between blood and blood vessels - very fine blood vessels

venule

smallest veins and receives blood from capillaries to the heart

vein

return blood to the heart, carrying deoxygenated blood from tissues and organs

what happens in the cardiac cycle

coordination of contraction (systole) and relaxation (diastole)

• electrical signals that allows both atriums to contract (systole) and push blood into the ventricles (diastole)

• when it reaches the node (flaps) between right atrium and ventricle it empties the blood from atria into the ventricle

• the electrical signal induces ventricular contraction and pumping blood into the aorta and pulmonary artery

• blood fills the atria when it is in diastole

explain the features of the lungs that maximise respiratory gas exchange between alveoli and capillaries

the highly branched system of the capillaries maximises the surface area thus maximises the respiratory gas exchance as the highly branched capillaries are on top of the alveolis.

and the alveoli cells lining alveoli and endothelial cells lining blood vessel allow a shorter diffusion distance due to the thinness and flatness.

partial pressure differences too

fluids in capiliaries

through water potential, the interstitual fluid will always be stable just like the osmotic pressure (as it contains large proteins) at the arteriole end the blood pressure is high so it is more negative in the capiliaries thus absorption occurs between interstitual fluid and the arteriole end of the capillaries. Whilst on the other end, at the venule end, the blood pressure is low so this is where filtration will occur and fluids flow out.

kidney disease can result in decreased concentration of plasma in the blood which can result in oedema (abnormal increase in interstitial fluid). why this occurs using knowledge of capillary exchange

explain why an open circulatory system allows insects to continue living when they lose a limb/head

open circulatory system has very slow blood flow so therefore, insects are able to still live in additon the open ended vessels allows surviva even when missing a body part.

identify the advantages of a closed circulatory system

organism can still live when a body part has been severed off

less energy is needed to supply the blood flow

explain how efficient exchange of substances occurs between capillaries and the interstitial fluid

efficient exchange of substances occurs between capillaries and the interstitial fluid down the concentration gradient, where the capillaries have lots of oxygen and nutrients thus will diffuse down the gradient and into the interstitual fluid, whilst there is a lot of CO2 and waste from the cell in the interstitual fluids which will diffuse into the capilliaries.