transport in animals Flashcards
explain the need for a transport system in an animal
SIZE- the cells are further away from the surface therefore the diffusion distance is increased so rate increased and is too slow and outer layers will use up supplies.
SA:VOL- larger animals have a smaller SA:VOL so gases required for volume can’t be supplied through diffusion as the surface area for exchange is too small
METABOLIC- animals are active so release energy food from respiration which requires lots of oxygen for movement energy
define the term single circulatory system
blood flows through the heart once for each circuit of the body
what is an advantage of the double circulation system?
blood made to flow quicker from increasing blood pressure by the heart and maintained in the systemic circulation
define the term double circulatory system
blood flows through heart twice for each circuit of the body. pulmonary - carries blood to lungs
systemic - round body
define the term closed circulation
blood is transported and stays in blood vessels
what is the only layer in a capillary and what is it’s function ?
endothelium, reduces diffusion distance and walls are leaky to allow substances to leave the blood
what is the process of open circulation ?
blood enters heart-like muscle through Ostia then pumps blood toward the head by peristalsis then pours into body cavities, bodily movements will effect the circulation
what type of circulation does a fish, mammal and insect have ?
closed single, closed double, open
what are 5 disadvantages of the open circulatory system ?
blood is at low pressure so flows slowly, circulation may be effected by lack of body movements, can’t rely on blood to transport nutrients round, steep diffusion gradient can’t be maintained, volume of blood flowing to certain tissues can’t be varied upon need
define the term open circulatory
blood is not transported I’m blood vessels and flows throughout the bodily cavity so that tissues are bathed in blood
in an artery which tissue has the biggest layer and what is the purpose of this ?
smooth muscle, maintain shape, to keep the lumen open allow blood through, and pressure
what tissues are present in order from in to out in an artery ?
endothelium, smooth muscle, collogen
explain which blood vessel has the smallest lumen?
artery, to maintain high pressure
what tissues are present in order from in to out in an vein ?
endothelium, smooth muscle, elastic fibres and collagen
what is the purpose of the collagen in the blood vessel walls ?
reinforce walls so they don’t break under pressure and loose shape from high pressure in arteries.
thin layer in the vein due to it not being at as high of a pressure
what are the purpose of the elastin fibres in blood vessels ?
helps vessel expand upon a pump of the heart and recoil to push blood around body and maintain pressure, larger in arteries than veins
how can blood be moved up the leg be skeletal muscles ?
walls of vein are thin so can be flattened by surrounding skeletal muscles contracting which applies pressure to blood because it decreases the volume of the lumen and therefore forcing blood to move
what are the 6 layers of the heart wall? inner -outer
endocardium, myocardium, epicardium, pericardial cavity, parietal pericardium, fibrous pericardium
explain what layer of the heart wall is the thickest ?
myocardium, mostly cardiac muscle, thick layer as it is required to contract the heart
what is the role of the epicardium?
reduces friction
what is the role of the pericardial cavity ?
secretes pericardial fluid to aid beating movement and reduce friction
what is the role of the (fibrous) pericardium ?
protects heart from over expansion and infection
how are muscle fibres connected to each other?
connections called intercalated discs
define the term myogenic
contracts without external stimulation so therefore can beat in a regular rhythm and never tires
state the difference between blood plasma and tissue fluid in what they carry
plasma - many blood cells (red, white), dissolved substances, and platelets and flows in vessels
tissue fluid - plasma but no blood cells or platelets or large plasma proteins, surrounds cells
state how tissue fluid is formed (1mark)
plasma leaking from capillaries
explain the process of how plasma is forced out of the capillary
when an artery reacts a capillary it has a higher hydrostatic pressure than oncotic pressure which results in a net movement of blood pressure out of the capillary into surrounding tissue
what is the function of blood plasma?
surround cell to allow exchange of gases and nutrients across plasma membranes of cells
what is hydrostatic pressure?
pressure exerted by blood on vessel wall