Human Transport System Flashcards
(38 cards)
What are the components of blood?
Red blood cells
White blood cells
Platelets
Plasma
What are Red blood cells ?
Biconcave discs containing no nucleus but plenty of protein called haemoglobin.
The majority of the other half of the blood contains red blood cells
What are White blood cells?
Large cells containing a big nucleus, different types have slightly different structures and functions.
The remaining fraction of the blood consists of white blood cells
What are Platelets?
Fragments of cells
The remaining fraction of the blood contains platelets
What is Plasma?
Straw coloured liquid
Over half of the volume of the blood is made up of plasma
What do red blood cells do?
Red blood cells are specialized cells which carry oxygen to respiring cells.
How are red blood cells adapted to their function?
They are full of haemoglobin, a protein that binds with oxygen to form oxyhaemoglobin.
They have no nucleus which creates more room inside the cell to pack in oxygen molecules
The shape of a red blood cell is described as being ‘biconcave disk’ this shape gives them a large surface area to volume ratio to maximise diffusion of oxygen in and out.
What does plasma transport?
Carbon dioxide – dissolved in the plasma as hydrogencarbonate ions and transported from respiring cells to the lungs
Digested food and mineral ions – dissolved particles absorbed from the small intestine and delivered to requiring cells around the body
Urea – Urea is dissolved in the plasma and transported to the kidneys
Hormones – chemical messengers released into the blood from the endocrine organs (glands) and delivered to target tissues/organs of the body
Heat energy – created in respiration, heat energy is transferred to cooler parts of the body or to the skin where heat can be lost
Actions of white blood cells
They can destroy pathogens in two ways:
Phagocytosis - the WBC phagocyte eats the pathogen alive by engulfing the pathogen and digesting the organism using digestive enzymes found in the phagocyte.
Anti-body production - antibodies are released and they have a complementary shape to the pathogen, they then bind to the pathogen, rendering it harmless.
What does vaccination do?
Vaccination stimulates the production of antibodies against a particular pathogen. Usually a dead or weakened form of the pathogen is used, which is sufficient to stimulate antibody production without the person becoming ill.
How does vaccination work?
During activation of the immune response, memory cells are generated. These are a type of antibody-producing white blood cell which will ‘remember’ the pathogen if re-infection occurs. If the same pathogen is detected in the body, the memory cells already have the appropriate antibodies ready to enable a quick, effective immune response.
What does a platelet do?
Platelet helps clot the blood.
How does a platelet clot the blood?
When there is a wound, the platelet arrive to stop the bleeding. A series of reaction occur within the plasma. Platelets release chemicals that cause soluble fibrinogen proteins to convert into insoluble fibrin and form an insoluble mesh across the wound, trapping red blood cells and therefore forming a clot.
The clot eventually dries and develops into a scab to protect the wound from bacteria entering
What’s the importance of blood clotting?
Blood clotting prevents continued blood loss from wounds.
Scab formation seals the wound with an insoluble patch that prevents entry of microorganisms that could cause infection.
It remains in place until new skin has grown underneath it, sealing the skin again.
Oxygenated blood
Oxygenated blood from the lungs enters the left side of the heart and is pumped to the rest of the body (the systemic circuit).
The left ventricle has a thicker muscle wall than the right ventricle as it has to pump blood at high pressure around the entire body,
Deoxygenated blood
Deoxygenated blood from the body enters the right side of the heart and is pumped to the lungs (the pulmonary circuit).
The right ventricle is pumping blood at lower pressure to the lungs
What is the septum?
A muscle wall that separates the two sides of the heart
Where is the blood pumped
Blood is pumped towards the heart in veins and away from the heart in arteries
What’s the purpose of valves?
To prevent the back flow of blood
The pathway of blood through the heart
- Deoxygenated blood coming from the body flows through the vena cava and into the right atrium
- The atrium contracts and the blood is forced through the tricuspid (atrioventricular) valve into the right ventricle
- The ventricle contracts and the blood is pushed through the semilunar valve into the pulmonary artery
- The blood travels to the lungs and moves through the capillaries past the alveoli where gas exchange takes place
- Low pressure blood flow on this side of the heart prevents damage to the capillaries in the lungs
- Oxygenated blood returns via the pulmonary vein to the left atrium
- The atrium contracts and forces the blood through the bicuspid (atrioventricular) valve into the left ventricle
- The ventricle contracts and the blood is forced through the semilunar valve and out through the aorta
- Thicker muscle walls of the left ventricle produce a high enough pressure for the blood to travel around the whole body
Causes of coronary heart disease
Layers of fatty material (plaque) build up inside the coronary arteries.
These fatty deposits are mainly formed from cholesterol
Effect of CHD
If a coronary artery becomes partially or completely blocked by these fatty deposits, it loses its elasticity and cannot stretch to accommodate the blood which is being forced through every time the heart contracts.
The flow of blood through the arteries is reduced, resulting in a lack of oxygen for the heart muscle
Partial blockage
the coronary arteries creates a restricted blood flow to the cardiac muscle cells and results in severe chest pains called angina
Complete blockage
means cells in that area of the heart will not be able to respire aerobically, leading to a heart attack
