Circulatory System Flashcards
How does plasma contribute to homeostasis of the body
Maintaining optimum pH of blood through buffers
Maintaining water potential of blood: Blood solutes affect water potential and is largely due to presence of sodium ions and plasma proteins. Regulates movement of water between blood and tissues.
Maintains temperature of the blood as water in the blood plays a part in distribution of heat
What is the function and adaptations of red blood cells
Functions to transport oxygen and carbon dioxide
Adaptations:
Presence of haemoglobin
Circular, flattened biconcave disc shape
No nucleus
Elastic and can turn bell-shaped
Why are red blood cells elastic
In order to squeeze through blood vessels smaller than itself in diameter without breaking
Function of white blood cells
Function to protect the body against disease-causing organisms
Shape and functions of phagocytes
Irregular in shape with lobed nucleus so it can move, changes shape and squeezes through capillary walls
Function: Engulf and ingest foreign particles by phagocytosis
Phagocytosis is process of engulfing and ingesting foreign particles. In process of fighting bacteria, phagocytes are killed with bacteria forming pus.
Shape and functions of lymphocytes
Round in shape, large nucleus
Function: When pathogens or disease causing organisms enter bloodstream, they stimulate lymphocytes to produce antibodies to protect body against bacteria by:
Agglutination, causes bacteria to clump together and attract phagocytes to engulf clump bacteria by phagocytosis. Antibodies neutralise toxin produced by bacteria
Describe platelets
They function to prevent excessive blood loss from body and entry of pathogens, either by formation of platelet plug or initiating blood clotting. They are small cell fragments without nucleus
Importance of blood clotting
Seals the wound to prevent entry of bacteria and further loss of blood
Describe blood clotting
When blood vessels are damaged, damaged tissue and platelets produce thrombokinase which converts prothrombin into thrombin(enzyme). Thrombin converts soluble fibrinogen into insoluble fibrin threads that trap red blood cells and whole mass forms a clot or scab
How does body prevent excessive blood clotting
Undamaged blood vessels contain anti-clotting substance called heparin. When thrombokinase is released in damaged tissues, it neutralises heparin so clotting can take place
Why is blood typing important
If the wrong type of blood is transfused, this would cause agglutination(binding of antibodies in recipients plasma to antigens on donated RBCs) or clumping of red blood cells and could lead to death as clumps may block small blood vessels and prevent flow of blood. Red blood cells become cross-linked to one another and trigger immune system to rupture RBCs and released haemoglobin may cause kidney damage
Why is blood group O universal donor
There are no antigens on donor’s red blood cells and thus recipients antibodies would not cause agglutination of donor’s blood
How is blood typing done (using anti-A serum)
If blood agglutinates when serum is used, RBCs contain antigen A
Why is there a need for transport system
In simple unicellular organism, movement of materials in and out of cell occurs by diffusion as no part of cell is far from external environment
In multicellular organism, transport system is needed to carry materials from one part of the body to another, as cells are located deep in body far from external environment
What are advantages of double circulation
Complete separation of oxygenated and deoxygenated blood in double circulation
Blood passes through heart twice in one complete circuit: pulmonary circulation at lower pressure and systemic circulation at higher pressure
