Topic 5:Transport in humans Flashcards
what are the main parts of human circulatory system?
blood,blood vessels,heart
what are the components that are consisted in the blood?
1.Red blood cells
2.White blood cells
3.Plasma
4.Platelets
what component makes up the majority of the blood?
Plasma
what are the 2 main ways white blood cells protect the body against diseases and infections?
1.White blood cells called phagocytes carry out phagocytosis to engulf and ingest foreign pathogens like bacteria and viruses, and break them down
2.Other white blood cells like lymphocytes produce antibodies which :
-Bind to and neutralise toxins produced by pathogens
-cause bacteria to clump together or agglutinate so they are more easily ingested by phagocytes
what exactly are platelets?
not cells, but small fragments of cytoplasm
describe the process of how blood clotting occurs
1.Damaged tissues and platelets release thrombokinase(enzyme)
2.Thrombokinase converts prothrombin(a protein found in the plasma) into another enzyme,thrombin in the presence of calcium ions
3.Thrombin catalyses the conversion of soluble fibrinogen (protein found in the plasma)into insoluble fibrin threads
4.Fibrin threads form a fibrin mesh which traps red blood cells to form a blood clot,which becomes a scab
describe the function ,structure/feature ,and how structure of red blood cell aids its function
function:Binds oxygen reversibly to transport oxygen from alveoli in the lungs to all cells
structure/features:
1.Circular,biconcave shape
2.contains haemoglobin
3.Has no nucleus
4.flexible,elastic cell membrane
How structure aids its function :
1.Greater surface area to volume ratio to increase rate of diffusion of oxygen into and out of RBC
2.Haemoglobin binds oxygen reversibly in RBC->binds oxygen easily in the alveoli and releases oxygen easily to tissues during transport
3.More space to contain more haemoglobin to bind more oxygen to be transported
4.Allows RBCs to become bell-shaped,allowing it to squeeze through and move through small capillaries
1.state the function of white blood cell and what types of white blood cells are there
2.State the structure/feature
3.How structure aids its function
1.protect against diseases and infections
1st type:lymphocytes
2nd type:phagocytes
2.Structure/function:
-fewer than RBCs
-Larger than RBCs
-contain nuclei and no haemoglobin
3.lymphocytes:produces antibodies that binds to toxins to neutralise them
Phagocytes:carry out phagocytosis to break down foreign particles like bacteria
1.State the function of plasma
2.Structure/feature
3.How structure aids its function
1.Transport medium transporting blood cells,and essential substances like glucose,and wastes like urea and carbon dioxide in the form of hydrogen carbonate ions .Also transports other substances like hormones,vitamins,plasma proteins
2.
-pale yellow fluid
-main component of blood
3.
-Plasma is a fluid->allows blood to flow
-allows substances like carbon dioxide and glucose to dissolve in it to be transported
1.state the function of platelets
2.structure/features
3.How structure aids its function
1.Clots blood when there is an open wound to:
-prevent excessive blood loss ,and
-prevent bacteria from entering wound
2.small fragments of cytoplasm
3.-state how blood clotting works-
describe antigens and antibodies
1.Antigens are proteins found on surface of the red blood cells.
-all the red blood cells of a person will have the same type of antigens
-There are 2 possible types of antigens, called Antigen A and Antigen B(must be capital)
2.antibodies are proteins produced by White Blood Cells which usually bind to toxins/foreign chemicals in blood to neutralise them.
-Antibodies which bind to Antigen A are Antibody-a
-Antibodies which bind to Antigen B are called Anti-body B
If both Antibody-a and Antigen A are present in the blood at the same time, Antibody-a would then bind to Antigen A.Antibody-a is specific to Antigen A.This causes red blood cells to clump together .
->agglutination occurs
->blood cannot flow as it is less fluid
Describe the muscle wall of the artery and explain why the feature
-Thick,elastic muscular wall
-Reason:Arteries receive blood directly pumped out from the heart at high pressure.
-Thick muscle wall->to withstand the high blood pressure
-elastic muscle wall->allows wall to stretch and recoil to push the blood in spurts as it is pumped out
Describe the muscle wall of vein and explain the feature
-Thin muscular wall
-Reason:blood pressure in veins is very low->less need for the muscle walls to be thick/elastic
explain why capillaries have no muscular wall and describe what type of wall it has
-It has a one-cell thick wall.
-Reason:function of capillary is to allow exchange of substances.The wall is partially permeable which allow diffusion of substances across walls.The wall is also one-cell thick so it reduces distance for diffusion
1.Describe lumen of artery
2.describe lumen of vein
3.describe lumen of capillary
1.Small lumen relative to its diameter
2.large lumen relative to its diameter
3.Large lumen relative to its diameter
describe how exchange of substances take place and what substances are involved
-substances like oxygen,glucose,amino acids,diffuse from the blood in the capillaries,across the one-cell thick wall of the capillaries,into the tissue fluid,and then into the cells,down a concentration gradient
-waste substances like carbon dioxide diffuse from the cells,into the tissue fluid,then across the one-cell thick capillary wall and into the blood,down a concentration gradient
if blood in veins have such low pressure,how then does the blood flow ?
muscles around the veins have to contract
what is the name of the wall that divides left and right ventricle?
median septum
what are the names of the stages in cardiac cycle when there is ventricular contraction or ventricular relaxation
ventricular contraction->systole
ventricular relaxation->ventricular systole
what are the 4 factors causing coronary heart disease
1.Smoking
2.diet high in fat and/or cholesterol
3.Lack of regular exercise
4.prolonged stress
How is coronary heart disease caused?
1.Cholesterol and fats are accumulated and deposited on inner walls of the coronary arteries,forming plaque
2.Coronary arteries become narrower and become blocked
3.blood containing glucose and oxygen cannot be transported to the heart muscles
4.heart muscles cannot carry out respiration to release enough energy
5.heart muscles cannot contract,causing heart attack.Heart muscle cells die.
