chapter 8 -transport in animals Flashcards
what is the need for specialised transport systems in animals
high metabolic demands so diffusion over long distances alone is not enough
relatively small SA:V ratio
molecules like hormones or enzymes may be made in one place but needed in another
food will digested in one organ system but needs to be transported to every cell for respiration
waste products of metabolism need to removed from cells and transported to excretory organs
what are features of circulatory system
liquid transport medium that circulates around system
vessels that carry transport medium
pumping mechanism to move fluid around system
what type of transport system is this
mass transport system
what is an open circulatory system
liquid medium pumped straight from heart into body cavity of animal ( haemocoel)
what is insect blood called
haemolymph
what does haemolymph do
transports food and nitrogenous waste and cells involved in defence against disease
doesnt carry oxygen or co2
what is a closed circulatory system
blood is enclosed in blood vessels and does not come directly into contact with cells of they body
what is a single closed circulatory system
blood travels only once through the heart for each complete circulation of body
what is double closed circulatory system
blood is pumped from heart to lungs to pick up oxygen and unload carbon dioxide and returns to heart
blood flows through heart and is pumped out to travel all around body before returning to heart again
what are components of blood vessel
elastic fibres - stretch and recoil providing vessel walls with flexibility
smooth muscle- contracts or relaxes which changes size of lumen
collagen - provides structural support to maintain shape and volume of vessel
what do arteries do
carry blood away from heart to tissues of body. Carry oxygenated blood except pulmonary artery which carry deoxygenated blood from heart to lungs and umbilical artery which carriers deoxygenated blood from fetus to placenta
what do artery walls contain
elastic fibres to withstand force of blood pumped out of heart and stretch
smooth muscle
collagen
what do arterioles do
link arteries and capillaries
what is difference between arteries and arterioles
arterioles have more smooth muscle but less elastin in walls as they ahve little pulse surge but can contrict or dilate to control flow of blood into individual organs
what is vasoconstriction
when arterioles contract constricting vessle and prevent blood flowwing into capillary bed
what is vasodilation
when arterioles relaxed dilating vessels and allowing blood to flow throufh into a capillary bed
what do capillaries do
link arterioles with venules. form extensive networj throughout all tussue if body
adaptations of capillaries
large SA for diffusion of substances in and out of blood
total cross sectional area of capillaries are greater than arteriole supplying them so rate of blood flow falls for more time gor exchange of materisal
walls are singel endothelial cell thick giving thin layer for diffusion
what do veins do
carry blood away from the heart
what vessels carry deoxygenated blood back to heart
inferior vena cava
superior vena cava
what do walls of veins consist of
lots of collagen and relatively less elastic fibre
wide lumen and has endothelium
what do venule consist of
thin walls
little smooth muscle and elastin
how is blood pumped up vein to heart against gravity
veins have one-way valves at intervals to prevent backflow of blood
veins run between big active muscles to squeeze veins when they contract forcing blood towards heart
breathing movement of chest acts as pump- squeezin actions and pressure changes move blood in veins of chest towards heart
what are the functions of blood
transport oxygen and co2 from respiring cells
transport digested food from small intestine
transport nitrogenous waste from cells to excretory organs
transport hormones
transport food molecules from storage compounds to cells that need them
transport platelets to damaged areas
transport cells and antibodies involved in immune response
