Circulation Flashcards
What helps the blood to clot?
blood platelets
What cells protect against disease?
white blood cells
what cells transport oxygen
red blood cells
some functions of the blood?
-to supply/remove water
-carry oxyge, CO2, waste and nutrients around the body
-protect the body against infection through white blood cells
what does plasma contain?
fibrinogen- blood clotting
serum-(water, marrow,proteins,hormones,antibodies,enzymes)
why are red blood cells good at their Jon?
-huge number of them
-tiny to allow them to pass through narrow capillaries
-have a flattened disc shape to increase surface area allowing rapid diffusion of oxygen
-contain haemoglobin which absorbs oxygen in lungs and releases oxygen in the rest of the body
why are white blood cells good at their job?
-can engulf bacteria and other pathogens by phagocytosis
-they can change shape easily and produce enzymes that digest the pathogens
why are blood plasma good at their job?
-straw-coloured liquid. transport dissolved substances around the body including:
hormones
antibodes
nutrients, such as water, glucose, amino acids, minerals and vitamins
-water substances, such as carbon dioxide and urea
what produces red blood cells in mammals?
bone marrow
what does birds blood contain
erythrocytes (red blood cells)
leucocytes (white blood cells)
thrombocytes (platelets)
what transport function does the heart and blood vessel carry out?
-carry food molecules, water and oxygen to cells and remove waste products such as carbon dioxide. They form the circulatory system
steps of the circulatory system
-blood gets pumped from the heart to the lungs and picks up oxygen
-the blood is then taken back to the heart
-the heart pumps the blood to the intestine (where oxygen and glucose is removed)
-and to the rest of the body (where oxygen is removed)
-after the oxygen and glucose have been removed for respiration the blood is sent back to the heart and starts again
what is double circulation
circulation system in which blood flows through the heart twice
define pulmonary circulation
blood flow between the heart and lungs
define systemic circulation
movement of the blood from the heart through the rest of the body (excluding the lungs) then back to the heart
Advantages of double circulatory system
-mammals because it increases the pressure and hence the flow rate of blood supplied to the tissues of the body via the systemic circulation.
how many cavities does the adult mammalian have ?
4 cavities
what are the mammalians heart divided into?
top two- atria (atrium)
bottom two- ventricles
function of the right atrium in the avian heart?
receives deoxygenated blood from the body and delivers it to the right ventricle which pumps it to the lungs (pulmonary)
function of the left atrium in the avian heart?
receives oxygenated blood from the lungs and delivers it to the left ventricle, which pumps it to the rest of the body (systemic)
what are the differences in the avian heart compared to mammalian?
-4 pulmonary veins rather than 2
-they have a right aortic arch- mammals don’t
what does the left ventricle do?
pumps blood to all of the boy
what does the right ventricle do?
pumps blood to the lungs from where it returns to the left side of the heart
steps of the avian heart
-blood fills the atria and the bicuspid and tricuspid valves are closed
-atria gently contract and push their blood into the two ventricles
-ventricles start to contract, this closes the atrioventricular valves and pushes the blood out through the semi-lunar valves into the pulmonary artery and aorta.
structure of blood vessels- tunica intima
thin inner lining (endothelium) that is very smooth and enables blood to flow through the vessels without causing friction
structure of blood vessels- tunica externa
tougher outer layer that helps to protect the vessel from pressure exerted from external organs rubbing against it
structure of blood vessels- tunica media
middle layer containing muscles and elastic fibres
adaptations of the arteries
-carry blood from the heart
-muscular walls to withstand pressure
-divide into arterioles
-the aorta is the largest artery in the body
adaptations of the veins and venules
-returns blood to the heart
-thin-walled, elastic, acts as blood reservoirs
-non-return valves
-superior and inferior vena cava are both large key veins
adaptations of the capillaries
-narrow, single layer of cells
-direct contact with tissues, allows diffusion
