Transport in humans

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why are transport systems rewquired in humans

Back

diffusion alone is inadequate for our cells in obtaining useful substances and removing excretory and toxic substances

Front

what is the functions of thing scirculry system is made of and what circulatry sustem is made of

Back

circulatory system consists of ehart, a msucula rpump that drives blood aroudn the body, blood, a fluid tissye that carries various substances aroud the body, and blood vessels that carry blood around the body

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characterisic of human circulatory system + its advantage

Back

human circulatory system is a double ciruclatory system in which the blood flows through the heart twice in one circuit, the advantage is that this allows blood to be pumped at low pressure to the lungs so the blood can be properly oxgeneated and the blood can be pumped out at high pressure to all body cells at a fast rate.

Front

explain double circulation in humans

Back

a double circulation consists of pulmonary circulation and systemic circulation, the pulmonary circulation links the lungs and the heart it carries oxygenated blood from heart to lungs and dexoygenated blood from heart to lungs. gaseous exchnage happens in the lings

in the systemic circulation, oxygenated bloood leaces the left side of the heart and is carried by the arteies to the rest of the body and the dexosygenated blood is carried from all parts of the body back to the right side of the heart via veins and the gaseous exchnage happens at the cells of the body.

Front

why is blood a fluid tissue, what is its components and its function?

Back

blood is a fluid tissue because it contians cells suspended in the plasma, it consists of plasma (55) and then rbc, wbc, and platelets.

two functions :

1: to transport oxygen, food substances, waste materials, hormones and heat from one part of body to abother part of body

2: to protect the body by preventing foreign entry of bodies and fighting infections

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plasma

Back

plasma is a fluid part of blood(55%)

it consists of 90% water and 10% dissovled substances such as mineral ions calcium chlorides etc , digested food substances glucose etc, metabolic waste products, plasma proteins, hormones hear

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RBC/ erythrocytes

Back

produced in bone marrow and broken down in spleen, they have a lifespan of four months and they transport o2 from lungs to rob

adaptrations:

1: haemoglobin is present in the cells because it binds reversibly to ocygen to form oxyhaemoglobin which helps transport oxygen in rbc to the rest of the body. each molecule of haemoglobing can bind up to four molecules of oxygen, it is ourplish red and after bdining with oxygen to hrom oxyhaemobglobin, it is bright red

2: it has no nucleues to allow for mroe haemoglobin ot be packed into the cells cytoplasm so more oxygen can be tranpsorted

3: it has a circular and biconcave shape to increase the surface area to volume ratio of the cell, allowing for quicker dffusion of oxygen in and out of the cell.

4: its cell surface memrbane is elastic and flexible so it can change its shape to squeeze through small capillaries.

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wbc/ leukocytes

Back

• larger and more numerous than rbc, they have a lifespan of only a few days,

• two main types:

• 1: lymphocytes which are round in shape and have a large round nucleus with non granulated small amount of cytolplasm. function to produce antibodies which protect body against diseases by 1. destroying bacteria by attatching to them and causing bacteria surface membrane to rupture

• 2: cause the bacteria to agglutinate so that they can be easily ingested by phagocytes

• 3: neutralise otxins produced by bacteria

• 4: attatch to viruses and prevent them from bidning to the host cell

phagocytes are more irregualr in shape and have a multilobed or bean shaped nuclei and ganulated cytoplams. they can move out of leaky capillaries to carry out phagocytosis--> a process where phagocytes engulf and digest pahtogens

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platelets/thrombocytes

Back

1. they are membrane bound fragments of larger bone marrow cells called megakaryocytes. they play an important role in blood clotting, by forming sticky plugs at wound cite

• - importance of blood clotting

1- precents excessive loss of blood from the wound

2- it prevents further entry of pathogens through the wound

• - process of blood clotting

1: damaged tissue and platelets produce an enzyme called thrombokinase.

2: an inactive enzyme called prothrombin is converted to an enzyme called thrombin in its active state by thrombokinase and calcium ions

3: fibrinogen is converted to insoluble fibrin threads via the thrombin enzyme to from a mesh to trap blood cells.

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TYPES OF BLOOD GROUPS

• + agglutination

Back

antigens is a protein marker found on the cell surface memrane and antibodies are a y shaped protein that bind to an antigen with complementaryshape,

agglutination is when the clumping of red blood cells occur when anti antibodies bind to their comeplementary antigen on red blood cell.

4 types of blood groups.

1: group a has tybe a red blood cell with antigen a, and therefore anti b antibodies in plasma, it causes agglutination if receives blood from b and ab group.

2: blood group b has red blood cell type b with b antigens and therefore anti a antiobodies, hence it causes agglutination if it receives blood from a or ab

3: blood group ab has blood cell type ab with both a and b anitgens, and no anti a or anti b antibodies, hecne it can receive any blood wihtout aggultination, since no anti a/b antiboides

4: blood group o has cell type o and no antigens and both anit a and anti b antibodies, hecne it can only efcieve o blood if not agglutinatio will occur.