Circulatory system Flashcards
(23 cards)
why do we need a circulatory system
for transportation of useful substances to body cells and to carry waste substances away from the body
useful substances
oxygen , water and digested fod
waste substances
urea , carbon dioxide
what is the function of the blood , blood vessels and heart
blood - transport substances around the body
blood vessels- tubes that carries the blood
heart- pumps the blood around the body
what is blood composed of
red blood cells, white blood cells and platelets
what is plasma and state 3 functions
plasma is the yellow fluid composed of 90% water and makes up 55% of blood. it transports digestive products to the liver from the ileum , urea from liver to kidneys and and hormones from glands to target organs
serum
plasma minus clotting factors
blood clotting
platelets in blood become spiky and stick close together and release an enzyme called thromboplastin together with calcium and vitamin k which coverts inactive plasma to thrombin which is then coverts plasma proteins into fibrin which forms a network across the cut and eventually dries and forms a scalp
blood groups
a, b, ab , o
blood vessels
veins . arties and capillaries
Arties
these transport blood from the heart to the body at high pressure very rapidly and only carries oxygenated blood with exception of the pulmonary arties. they lie deep in the body and have no valves except the pulmonary artery and aorta. has a narrow lumen and thick layer of muscle
capillaries
Transports blood throughout the body and links veins and arties the flow is at a low pressure ad very slow. they have no valves and are one cell thick so substances can pass into them easily
veins
transports blood from body to the heart at low pressure and low speed and the blood is deoxygenated besides in the pulmonary vein. THER ARE VALVES TO PREVENT BACKFLOW OF BLOOD. their lumen is wide and the are located close to the surface of the body
journey of blood through the heart
anterior/posterior vena cava, right atrium , tricuspid valves , right ventricle, semi lunar valves, pulmonary valves , lungs , pulmonary veins , left atrium , bicuspid valves , left ventricle , semi lunar valves , aorta , body
pacemaker
specialised cells that send electrical impulses that travel through the heart causing it to 75 times per minute
types of blood pressure
systolic pressure / diastolic pressure
why do we need double circulation
the blood losses pressure in lungs and the body
causes of heart attacks
fatty material builds up in the coronary artery and blocks oxygen supply
causes of hypertension
being over weight , smoking , lack of physical exercise and stress
symptoms of a heart attack
chest pains, shortness of breath and dizziness
lymph
transport medium which is colour less and forms from tissue fluids and flows from tissues to the heart
functions of lymph
removes body waste around body cells, helps maintain normal blood pressure
lymph nodes
these filter dead cells and cancerous cells out of lymph and release lymphocytes in time of infection