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2H-transport humans Flashcards

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1
Q

why can simple, unicellular organisms rely on diffusion for the movement of substances in and out of the cell? why do they have to rely on diffusion?

A

single-celled organisms have no circulatory system so materials can easily move around without a special system. they also have no lungs, gills, etc.,, instead, they obtain oxygen via diffusion through the surface membrane of the cell. they have high surface area to volume ratio so their surface membrane is large enough to be able to supply all the oxygen that their volume demands.

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2
Q

what can the supply to demand can be written as?

A

surface area/volume

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3
Q

why do multicellular organisms need a transport system?

A

large animals (multicellular organisms) can’t get all the oxygen they need through their surface (even if their body would allow it) because there isn’t a high enough surface to supply all the volume. to overcome this they have special gas exchange organs and circulatory systems (same idea applies to circulatory system)

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4
Q

what are the two main types of circulatory systems?

A

single and double

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5
Q

what is a single circulatory system?

A

when the blood is pumped from the heart to the gas exchange organ and then directly to he rest of the body

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6
Q

what is the double circulatory system?

A

the blood is pumped from the heart to the gas exchange organ, back tot he heart, and then to the rest of the body

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7
Q

what are the 2 parts of the double circulatory system?

A

pulmonary circulation- deoxygenated blood leaves the heart through the pulmonary arteries and is circulated through the lungs, where it becomes deoxygenated. the oxygenated blood returns to the heart through the pulmonary veins
systemic circulation- oxygenated blood leaves the heart through the aorta and is circulated through all other parts of the body, where it unloads its oxygen. the deoxygenated blood returns to the vena cava.

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8
Q

why is a double circulatory system more efficient than a single circulatory system?

A

this is because the blood it pumped twice, so the pressure is maintained and the blood is carried more quickly to organs

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9
Q

what is the human circulatory system comprised of?

A

the heart, blood, blood vessels (carry blood around the body)

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10
Q

what do the veins, arteries, capillaries do? what are the exceptions?

A

arteries - carry blood away from the heart towards other organs
veins- carry blood towards the heart and away from other organss
capillaries- carry blood through organs, linking the arteries and veins
APART FROM VENA CAVA VEIN AND PULMONARY VEIN

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11
Q

wher eis the renal artery and vein?

A

goes to and away from kidneys

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12
Q

where are the hepatic veins and arteries?

A

towards and away from liver

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13
Q

what is the hepatic portal vein?

A

connects digestive system to liver??

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14
Q

label the heart.

A

it must include:
aorta, vena cava, pulmonary artery, pulmonary vein, left atrium, bicuspid (mitral valve), left ventricle, right ventricle, right atrium, semi-lunar valves

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15
Q

how is blood moved around the heart? explain it step by step. what are these series events called?

A

the cardiac cycle:
1. blood enters the atria. it cannot yet pass into the ventricles because the bicuspid (mitral) and tricuspid valves are closed
2. the walls of the atria contract. this raises the pressure of the blood in the atria which forces open the bicuspid and tricuspid valves. blood passes through these valves into the ventricles
3. when the ventricles are full, they contract. this increases the pressure of blood in the ventricles which closes the bicuspid and tricuspid valves again. blood cannot return to the atria
4. the ventricles continue to contract and the pressure continues to increase. this forces open the semi-lunar valves at the base of the aorta and the pulmonary artery. Blood is ejected into these two arteries. the pulmonary artery carries blood to the lungs. the aorta had branches that carry blood to all other parts of the body
5. as the ventricles empty, higher pressure in the aorta and pulmonary artery closes the valves in these blood vessels. the cycle then begins again as the atria starts to fill with blood

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16
Q

how is blood moved around the heart? explain it step by step. what are these series events called?

A

the cardiac cycle:
1. blood enters the atria. it cannot yet pass into the ventricles because the bicuspid (mitral) and tricuspid valves are closed
2. the walls of the atria contract. this raises the pressure of the blood in the atria which forces open the bicuspid and tricuspid valves. blood passes through these valves into the ventricles
3. when the ventricles are full, they contract. this increases the pressure of blood in the ventricles which closes the bicuspid and tricuspid valves again. blood cannot return to the atria
4. the ventricles continue to contract and the pressure continues to increase. this forces open the semi-lunar valves at the base of the aorta and the pulmonary artery. Blood is ejected into these two arteries. the pulmonary artery carries blood to the lungs. the aorta had branches that carry blood to all other parts of the body
5. as the ventricles empty, higher pressure in the aorta and pulmonary artery closes the valves in these blood vessels. the cycle then begins again as the atria starts to fill with blood

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17
Q

how is the heart adapted to its function?

A
  • it is divided into a left and right side, with a wall of muscle called the septum dividing it. the wall of the left ventricle is much thicker than the right ventricle because it has to pump blood to all other parts of the body and requires more pressure
  • the valves ensure the blood can only flow in one direction through the heart
  • the walls of the atria are thin so that they can be stretched to receive blood as it returns to the heart but can contract with enough force to push blood through the bicuspid and tricuspid valves into the ventricles
    -the wall of the heart is made of cardiac muscle, which can contract and then relax continuously without becoming fatigued
  • the cardiac muscle has its own blood supply - the coronary circulation so blood reaches the muscle via coronary arteries. it is then returned via the coronary vein through the right atrium
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18
Q

how is the ventricle adapted to its function?

A
  • it is divided into a left and right side, with a wall of muscle called the septum dividing it. the wall of the left ventricle is much thicker than the right ventricle because it has to pump blood to all other parts of the body and requires more pressure
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19
Q

how are the valves adapted to its function?

A
  • the valves ensure the blood can only flow in one direction through the heart
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20
Q

how is the atria adapted to its function?

A
  • the walls of the atria are thin so that they can be stretched to receive blood as it returns to the heart but can contract with enough force to push blood through the bicuspid and tricuspid valves into the ventricles
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21
Q

how is the wall of the heart adapted to its function?

A

-the wall of the heart is made of cardiac muscle, which can contract and then relax continuously without becoming fatigued
- the cardiac muscle has its own blood supply - the coronary circulation so blood reaches the muscle via coronary arteries. it is then returned via the coronary vein through the right atrium

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22
Q

do both atria/ventricles contract at the same time?

A

yes

23
Q

what is coronary heart disease?

A

a disease where the coronary arteries are blocked by a build-up of fatty substances (including cholesterol) in their walls. this can cut off the blood supply to the cardiac muscle and therefore it can no longer receive oxygen and glucose (so it can’t respire and release energy). this could result in a heart attack and lead to severe problems.

24
Q

what factors make coronary heart disease more likely?

A
  • heredity - some people inherit a tendency to develop CHD
  • high blood pressure - puts more strain on heart
  • diet - eating large amounts of saturated fat is likely to raise cholesterol levels
  • smoking - raises blood pressure and makes blood clots more likely to form
  • stress - raises blood pressure
  • lack of exercise - regular exercise helps reduce blood pressure and strengthens the heart
25
Q

why do our hearts beat faster when we exercise?

A

This is because the muscles must release more energy. they need an increased supply of oxygen for aerobic respiration so to deliver the oxygen, both the number of beats per min and volume of blood pumped (heart rate) with each beat (stroke volume) increase

26
Q

why does our heart rate increase when we are afraid or angry?

A

the increased output from the heart supplies extra blood to the muscles, enabling them to release extra energy through aerobic respiration. this allows us to fight or run away and is called the ‘fight or flight response’. this is triggered by the secretion of the hormone adrenaline from the adrenal glands. (this also make you stomach fluttery because the blood that would normally flow to your stomach and intestines has been diverted to the muscles)

27
Q

why does our heart rate decrease when we sleep?

A

less energy is needed to be released so we need less oxygen.

28
Q

what controls the change in our heart rate?

A

nerve impulses from the medulla

29
Q

how is the medulla involved in increasing heart rate when we exercise?

A

our muscles produce more CO2 because we respire more. receptors in the aorta and carotid artery (artery leading to the head) detect this increase. they send electrical signals called nerve impulses through the sensory nerve to the medulla. the medulla responds by sending nerve impulses along the accelerator nerve. When CO2 production returns to normal, the medulla receives fewer impulses so it responds by sending nerve impulses along a decelerator nerve.

30
Q

what does the accelerator/decelerator nerve do?

A

A- increases heart rate and blood pressure
D- decreases heart rate and force of contractions so BP goes back to normal

31
Q

what do the arteries do? what is it made of? how does this relate to their function?

A

carry blood from heart to organs. This arterial blood is pumped out of the blood at high pressures. the elastic tissues of the arteries allow them to stretch and recoil (spring back into shape) maintaining high blood pressure. the thick muscle walls, with muscle fibres and elastic tissue, help control the flow of blood by dilating and constricting the vessels
the arteries have a small lumen (central cavity) and an endothelium linning

32
Q

what do the veins do? what is it made of? how does this relate to their function?

A

carries blood from organs back to heart. the pressure of venous blood is much lower than in the arteries. it puts little pressure on the walls of the on the walls of the veins, so they are thinner (thin walls with little muscle and elastic tissue) and contain less elastic tissue and muscle.
- there is a large lumen (central cavity)
- endothelium lining
- veins have semilunar valves which prevent backflow

33
Q

what are the exceptions to veins and arteries and the direction in which blood flows?

A

pulmonary artery and vein (+umbilical artery/vein)

34
Q

what do the capillaries do? what is it made of? how does this relate to their function?

A
  • carry blood through organs, bringing the blood close to every cell in the organ so that substances are transferred between blood and cells
  • they are very small, they only just about fit red blood cells
  • the capillary wall is one cell thick for short diffusion distance
35
Q

name the main components in blood.

A

plasma, red blood cells (erythrocytes), white blood cells (lymphocytes, phagocytes, platelets)

36
Q

what is plasma? what is its function?

A
  • liquid part of blood: mainly water
  • carries the blood cells around the body; carries dissolved nutrients, hormones, carbon dioxide and urea; also distributes heat around the body
37
Q

what is red blood cells? what is its function?

A

-biconcave, disc-like cells with no nucleus; millions in each mm^3 of blood
- transport of oxygen - contain mainly haemoglobin, which loads oxygen in the lungs and unloads it in other regions of the body

38
Q

what is lymphocytes? what is its function?

A
  • about the same size as red cells with a large spherical nucleus
  • produce antibodies to destroy microorganisms - some lymphocytes persist in our blood after infection and give us immunity to specific diseases
39
Q

what is phagocytes? what is its function?

A
  • much larger than red cells, with a large spherical or lobed nucleus
  • digest and destroy bacteria and other microorganisms that have infected our bodies
40
Q

where are red blood cells made? how long do they live? where are they destroyed?

A

bone marrow
They have a limited life span of about 100 days after which time they are destroyed in the spleen.

41
Q

what is haemoglobin? what does it do to oxygen?

A

an iron-containing protein.
haemoglobin associates (combines) with oxygen to form oxyhemoglobin when there is a high concentration of oxygen in the surroundings. We say that the red blood cell is loading oxygen. When the concentration of oxygen is low,
oxyhemoglobin turns back into haemoglobin and the red blood cell unloads
As red blood cells pass through the lungs, they load oxygen. As they pass through active tissues they unload oxygen in the lungs

42
Q

how are red blood cells adapted to their function?

A
  • they don’t have a nucleus which means more hemoglobin can be packed into each red blood cell so more oxygen can be transported.
  • they have a biconcave shape which allows for efficient exchange of oxygen in and out of the cell
  • each red blood cell has a high SA:VOL ratio increasing the rate of diffusion
  • the thin shape of the cell results in a short diffusion distance to the centre of the cell
  • contains haemoglobin, an iron-containing protein which associates with oxygen to form oxyhaemoglobin
43
Q

what do phagocytes do?

A
  1. phagocytes have a sensitive cell surface membrane that can detect chemicals produced by pathogen cells
  2. they ingest microorganisms such as bacteria through phagocytosis.
  3. they do this by changing their shape and producing extensions around their cytoplasm, called pseudopodia. The pseudopodia surround and enclose the microorganisms in a vacuole.
  4. once this is done, the phagocyte excretes digestive enzymes into the vacuole to break the microorganism down
44
Q

what type of response are the phagocytes? what about lymphocytes?

A

P-non-specific, L-specific

45
Q

what are lymphocytes? what do they do?

A
  • they make chemicals called antibodies. Antibodies are soluble proteins that pass into the plasma and they have a specific shape that is complementary to the antigens on the surface of the pathogen.
    1. pathogens such as bacteria and viruses have chemical ‘markers’ on their surfaces, which the antibodies recognise. these ‘markers’ are antigens
    2. the antibodies stick to the surface antigens and destroy the pathogen which can be done in a number of ways including: causing the bacteria to stick together, so the phagocytes can ingest them more easily, causing bacterial cells to burst open, neutralising poisons (toxins) produced by pathogens, acting as a ‘label’ on the pathogen so it is more easily recognisable to the phagocyte
    they can also make memory cells
46
Q

what is the function of plasma?

A

carries the blood cells around the body; carries dissolved nutrients, hormones, carbon dioxide and urea; also distributes heat around the body

47
Q

what is secondary immune response?

A

secondary immune response is much faster and more effective than the primary response. when lymphocytes develop memory cells which remain in the blood for many years (up to a lifetime). if the same microorganism re-infects a person, the memory lymphocytes start to reproduce and produce antibodies so that the pathogen can be quickly dealt with. This is immunity.
(no antibodies quickly rises, killing microorganism)

48
Q

what is vaccination? how is this done?

A

artificial immunity.
1. a person is injected with an ‘agent’ that carries the same antigens as a specific pathogen
2. lymphocytes recognise the antigens and multiply exactly as if that microorganism had entered the bloodstream
3. they produce memory cells and make the person immune to the disease
4. if the person comes into contact with the ‘real’ pathogen it will experience a secondary immune response. (antibody production happens sooner, faster, in greater quantity than if they had not been vaccinated and may be enough to prevent pathogen from reproducing and causing disease

49
Q

name some agent which are used in vaccines

A
  • a weakened strain of the actual microorganism, e.g. vaccines against polio, tuberculosis (TB) and measles
  • dead microorganisms, e.g. typhoid and whooping cough vaccines
  • modified toxins of the bacteria, e.g. tetanus and diphtheria vaccines
  • just the antigens themselves, e.g. influenza vaccine
  • harmless bacteria, genetically engineered to carry the antigens of a different, disease-causing microorganism, e.g. the vaccine against hepatitis B.
50
Q

what is the response to infection? (from the pathogen entering the bloodstream and the influence of phagocytes and lymphocytes)

A

Response to infection
* The stages of infection and the subsequent immune response are as follows:
1. The pathogen enters the blood stream and multiplies
2. A release of toxins (in the case of bacteria) and infection of body cells causes symptoms in the patient
3. Phagocytes that encounter the pathogen recognise that it is an invading pathogen and engulf and digest (non-specific response)
4. Eventually, the pathogen encounters a lymphocyte which recognises its antigens
5. The lymphocyte starts to produce specific antibodies to combat that particular pathogen
6. The lymphocyte also clones itself to produce lots of lymphocytes (all producing the specific antibody required)
7. Antibodies destroy pathogens
8. Phagocytes engulf and digest the destroyed pathogens

51
Q

what does an organism have immunity?

A
  • An organism has immunity when they have sufficient levels of antibodies to protect it from a particular disease
    • As a result, they do not suffer from the disease or its symptom
52
Q

what are platelets?

A

Platelets are not whole cells, but fragments of large cells made in the bone marrow.

53
Q

what do the platelets do if you have hurt yourself e.g., cut youself? what is its function?

A
  1. If the skin is cut, exposure to the air stimulates the platelets and damaged tissue to produce a chemical.
  2. This chemical causes the soluble plasma protein fibrinogen to change into insoluble fibres of another protein, fibrin.
  3. The fibrin forms a network across the wound, in which red blood cells become trapped
  4. This forms a clot, which prevents further loss of blood and entry of microorganisms that may be pathogens.
  5. The clot develops into a scab, which protects the damaged tissue while new skin grows.
54
Q
A

Biology MA (11 decks)

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