transport in humans Flashcards
what are the components of blood?
- red blood cells (45%)
- white blood cells (<1%)
- platelets (<1%)
- plasma(55%)
structure of rbc
biconcave disc shape, elastic cell surface membrane, no nucleus and contains haemoglobin
function of rbc
transports oxygen which combines reversibly with haemoglobin, transports some carbon dioxide
structure of white blood cell
lymphocytes have spherical nuclei with non-granular cytoplasm
phagocytes have lobed nuclei with granular cytoplasm
function of white blood cell
defend body against disease
phagocytes engulf bacteria by phagocytosis and digest them
lymphocytes produce antibodies to kill bacteria and neutralize toxins
structure of platelet
cell fragments from cytoplasm of certain bone marrow cells
function of platelet
release materials necessary for blood clotting
stick to surface of damaged blood vessels
structure of plasma
liquid component of the blood, made up of 90% water
functions of plasma
transports:
1. plasma protein involved in clotting
2. digested food (glucose and amino acids) to target cells
3. antibodies
4. hormones from secreting glands to target cells
5. metabolic waste from liver to kidneys for excretion
what do antigens do?
antigens provoke an immune response by producing antibodies (they are found on the surface of rbcs, antibodies found in blood plasma) Viruses and bacteria may present antigens that trigger response by immune system
How are people classified into different blood groups?
depends on which type of antigens and antibodies present in the blood
Blood type A
antigen A and antibodies B
Blood type B
antigen B and antibodies A
Blood type AB
antigens A and B, no antibodies
Blood type O
no antigens, antibodies A and B
What is agglutination?
Antibodies can recognise and bind to their specific antigens on RBCs, causing the RBCs to clump up and agglutinate. It can be lethal as clumping of RBCs can block smaller blood vessels and reduce blood flow, reducing the rate at which nutrients and oxygen is transported to respiring cells for energy to be released
which blood type is compatible with type A?
O and A
which blood type is compatible with type B?
O and B
which blood type is compatible with type AB?
Any
which blood type is compatible with type O?
O
what happens during blood clotting?
- When a blood vessel is injured, platelets begin to collect near the site of the injury and form a barrier called the platelet plug
- When platelets come into contact with the injured area, they become sticky and swell up, releasing certain chemicals
- Thrombinkinase is produced by platelets and damaged tissues which converts prothrombin into enzyme thrombin
- thrombin converts soluble fibrinogen into insoluble fibrin which forms a network of structures across the wounded area
- blood cells and platelets are emeshed into this network to form a blood clot
- serum is plasma without the blooding clotting factors and it is the yellowish remains that forms when blood clots
what is phagocytosis?
it is the process of engulfing and ingestion of foreign particles by phagocytes. in some instances, the phagocytes may be killed with the bacteria, forming a phagolysosome
When are antibodies produced?
when pathogens or diseas-causing organsims enter the bloodstream, lymphocytes are stimulated to produce antibodies