topic 10 - human transport Flashcards
why do unicellular organisms rely on diffusion?
When the surface area to volume ratio is large, there is a lot of surface area for diffusion and not much volume to travel within. which is why unicellular organisms rely on diffusion alone to get the substances they need.
why are transport systems needed in multicellular organisms?
multicellular organisms contain many layers of cells, meaning that the distance between the surface of the organism to its centre is relatively long. the diffusion distance is too great to rely on diffusion alone as it cannot occur at a sufficient rate to meet the needs of the organism, so larger organisms usually have transport systems, which is the circulatory system for humans.
components of blood
red blood cells, white blood cells, platelets and plasma
% of each component of blood
45% red blood cells, 55% plasma, less than 1% platelets and white blood cells.
structure of red blood cell
- biconcave
- no nucleus
- plenty of protein haemoglobin
structure of white blood cell
- large cell
- big nucleus
- all are slightly different
structure of platelet
fragments of cells
structure of plasma
straw coloured liquid
role of plasma in transporting CO2
CO2 is dissolved in the plasma as hydrogencarbonate ions and transported from respiring cells to the lungs
role of plasma in transporting digested food
the dissolved particles are absorbed from the small intestine and delivered to requiring cells around the body
role of plasma in transporting urea
Urea is the waste substance produced in the breakdown of proteins by the liver. Urea is dissolved in the plasma and transported to the kidneys
role of plasma in transporting hormones
hormones are released into the blood from the endocrine organs (glands) and delivered to target tissues/organs of the body
role of plasma in transporting heat energy
heat energy is transferred to cooler parts of the body or to the skin where heat can be lost
3 adaptations of red blood cells and how they help the transport of oxygen
- full of haemoglobin, a protein that binds to oxygen to form oxyhaemoglobin
- no nucleus which allows more space for haemoglobin to be packed in
- ‘biconcave disc, allowing them a large surface area to volume ratio to maximise diffusion of oxygen in and out
2 types of white blood cells
phagocytes and lymphocytes
function of phagocytes
- Phagocytes carry out phagocytosis by engulfing and digesting pathogens
- they are able to detect chemicals produced by pathogenic cells.
- Once they encounter the pathogenic cell, they will engulf it and release digestive enzymes to digest it, this is a non-specific immune response
function of lymphocytes
- Lymphocytes produce antibodies.
- antibodies have a shape that is specific (complementary) to the antigens on the surface of the pathogen.
- this is a specific type of immune response as the antibodies produced will only fit one type of antigen on a pathogen
what is it called when antibodies bind to antigens?
agglutination
points to include in exam question: explain the bodies immune response to disease
- phagocytes that encounter the pathogen recognise that it is an invading pathogen and engulf and digest (non-specific response)
- eventually, the pathogen encounters a lymphocyte which recognises its antigens
- the lymphocyte starts to produce specific antibodies to combat that particular pathogen
- the lymphocyte clones itself to produce lots of lymphocytes (all producing the specific antibody required)
- antibodies cause agglutination of pathogens
- phagocytes engulf and digest the agglutinated pathogens
- memory cells can produce much larger quantities of the required antibody in a much shorter time to fight off the pathogen before the patient suffers any symptoms if they encounter the same pathogen.
where are oxygenated and deoxygenated blood pumped in from and where do they go?
- oxygenated blood from the lungs enters the left side of the heart and is pumped to the rest of the body
- 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 from the body enters the right side of the heart and is pumped to the lungs
- the right ventricle is pumping blood at lower pressure to the lungs
which ventricle is thicker and why?
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. the right ventricle is pumping blood at lower pressure to the lungs
what separates the two sides of the heart
a muscle wall called the septum
what are veins and arteries?
veins pump blood towards the heart and arteries pump blood out of the heart
what are coronary arteries?
The coronary arteries supply the cardiac muscle tissue of the heart with oxygenated blood
what are valves?
Valves are present to prevent blood flowing backwards
structure of the heart (left and right)
RIGHT:
- pulmonary artery
- vena cava
- right atrium
- tricuspid valve
- right ventricle
LEFT:
- aorta
- pulmonary vein
- left atrium
- bicuspid valve
- left ventricle
semi-lunar valves are located on both sides of the heart below the pulmonary artery and aorta.
pathway of blood through the heart (from vena cava to the rest of the body)
- 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 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 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
how does adrenaline affect the heart?
adrenaline increases heart rate, breathing rate and blood pressure to provide more oxygen and energy to the muscles.
how does heart rate change during exercise?
Heart rate increases to deliver oxygen and glucose and remove waste more frequently. the volume of blood pumped out of the heart also increases to deliver bigger quantities of oxygen and glucose
what is CHD?
coronary heart disease is the block up in coronary arteries by fatty deposits, caused by high cholesterol.
- 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, which could lead to heart attacks
4 risks factors of CHD
- obesity - carrying extra weight puts a strain on the heart. increased weight can lead to Type 2 diabetes which further damages your blood vessels
- high blood pressure - this increases the force of the blood against the artery walls and consequently leads to damage of the vessels
- high cholesterol- speeds up the build up of fatty plaques in the arteries leading to blockages
- smoking - chemicals in smoke cause an increase in plaque build up and an increase in blood pressure
3 types of blood vessels
- veins
- arteries
- capillaries
5 key features of arteries
- carry blood at high pressure away from the heart
- carry oxygenated blood (except the pulmonary artery)
- have thick muscular walls containing elastic fibres - help withstand pressure
- have a narrow lumen - helps maintain high pressure
- blood flows through at a fast speed
6 key features of veins
- carry blood at low pressure towards the heart
- carry deoxygenated blood (other than the pulmonary vein)
- have thin walls
- have a large lumen
- contain valves - prevent back flow of blood as it has low pressure
- blood flows through at a slow speed
5 key features of capillaries
- carry blood at low pressure within tissues
- carry both oxygenated and deoxygenated blood
- have walls that are one cell thick - short diffusion distance for substances to pass through
- have ‘leaky’ walls - allows plasma to leak out
- speed of blood flow is slow
structure of the circulatory system
RIGHT:
- pulmonary artery - takes blood to lungs
- vena cava - takes blood into the heart
- hepatic vein - takes blood from the liver to the heart
- hepatic portal vein - takes blood between the liver and gut
- renal vein - takes blood from the kidneys to the heart
LEFT:
- pulmonary vein - takes blood from the lungs to the heart
- aorta - takes blood out of the heart
- hepatic artery - takes blood from the heart to the liver
- mesenteric artery - takes blood from the heart to the gut
- renal artery - takes blood from the heart to the kidneys
