Blood And Cirulation Flashcards

1
Q

What is a single circulatory system?

A

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

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2
Q

What is the double circulatory system?

A

The blood is pumped from the heart to the gas exchange organ, back to the heart and then to the rest of the body.
Humans have a double circulatory system and the main organ is the heart

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3
Q

What are the four main components of blood?

A
  1. Plasma
  2. Platelets
  3. Red blood cells
  4. White blood cells
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4
Q

Describe surface area to volume ratio

A

-Single-celled organisms have a high surface area to volume ratio, whereas larger animals have a lower surface are to volume ratio

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5
Q

What are the two distinct parts to the double circulatory system?

A
  • The pulmonary circulation, in which blood is circulated through the lungs where it is oxygenated.
  • The systemic circulation, in which blood is circulated through all other parts of the body where is unloads its oxygen
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6
Q

Why is the double circulatory system more efficient than the single circulatory system?

A
  • The heart pumps the blood twice so higher pressures can be maintained
  • The blood travels more quickly to organs
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7
Q

How does the heart work?

A
  1. The heart beat begins when the heart muscles relax and bloods flows into the atria.
  2. After blood enters the atria, the atria contract increasing the pressure of the blood in the atria and the bicuspid and tricuspid valves are forced open to allow blood to be pushed into the ventricles.
  3. The ventricles contract, increasing the pressure of the blood in the ventricles forcing the bicuspid and tricuspid valves to close to stop the blood from flowing backwards into the atria.
  4. The ventricles continue to contract and the pressure continues to increase, which forces open the semi-lunar valves at the base of the aorta and the pulmonary artery. The blood is ejected into these two arteries. PA takes blood to lungs whereas A has branches.
  5. As pressure increases in A and PA the semi-lunar valves are closed and at the same time the atria are relaxing and once again filling with blood
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8
Q

How does our heart rate change?

A
  • When we sleep our heart rate decreases as all our organs are working more slowly and so they need to release less energy as no need less oxygen
  • When we are scared, our heart rate increases so that more blood can reach our muscles so that more energy can be released through aerobic respiration, allowing us to fight or run away
  • When we exercise our muscles need more oxygen for aerobic respiration as they must release more energy. Therefore our heart rate increases so both the number of beats per minute and the volume of blood pumped with each beat (stroke volume) increases
  • These changes are brought about by nerve impulses from the medulla
  • The accelerator nerve increases heart rate and the force with which the heart beats which increases blood pressure, decelerator nerve does the opposite
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9
Q

Describe arteries

A
  1. They carry blood away from the heart to organs of the body
  2. They have a thick muscle layer with elastic fibres ( The blood pumped out by ventricles puts pressure on walls of arteries and so this allows the walls to stretch, they can also recoil and help to push blood along)
  3. Valves are only in the pulmonary artery and aorta
  4. The arterial blood has a very high pressure and feel a pulse
  5. Carries oxygenated blood except from in the pulmonary artery
  6. Blood is rich in oxygen and low in carbon dioxide
  7. Narrow lumen
  8. No valves
  9. Largest artery in the body is the aorta
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10
Q

Describe viens

A
  1. They carry blood towards the heart
  2. They have a thin muscle layer with fewer elastic fibres (the blood puts very little pressure on the walls of the veins and must be able to allow blood to pass through easily)
  3. Has valves to stop the blood from going in the wrong direction
  4. The venous blood has a lower pressure than in arteries and no pulse
  5. Carries deoxygenated blood apart from pulmonary vein
  6. Blood is low in oxygen and hight in carbon dioxide
  7. Wide lumen
  8. Valves
  9. Largest vein in the body is the Vena Cava
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11
Q

Describe capillaries

A
  1. Arteries branch int capillaries and link veins (they are very tiny)
  2. One cell thick (permeable walls)with no muscle (increases rate of diffusion by decreasing the distance over which it happens)
  3. No valves
  4. The pressure goes from high to low as blood moves through
  5. They carry the blood really close to every cell in the body to exchange substances between the blood and other body cells
  6. From oxygenated to deoxygenated as oxygen diffuses out as they supply food and oxygen and take away wastes such as carbon dioxide
  7. A collection of capillaries is known as a capillary bed
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12
Q

What are the three different types of blood vessels?

A

-Arteries
-Capillaries
-Veins
The exchange of substances between the blood and the body can only occur through capillaries.

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13
Q

What are red blood cells? How are they adapted for their function?

A
  1. A biconcave disc that is rounded and flat, to give a large SA for absorbing and releasing oxygen
  2. No nucleus to provide more space for haemoglobin so they can carry more oxygen
  3. Contain haemoglobin, a molecule specially designed to hold oxygen and carry it to the cells that need it, transport oxygen
  4. Can change shape to a decent extent, without breaking as it squeezes through single file through the capillaries
  5. Stem cells in bone marrow make red blood cells
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14
Q

What are platelets? What is their function?

A
  1. They are bits of cell broken off larger cells
  2. Platelets produce tiny fibrinogen fibres to from a net, which traps other blood cells to form a blood clot, this process also needs other proteins called clotting factors to work properly
  3. This prevents microorganisms from entering the wound and stops you from loosing too much blood.
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15
Q

What is plasma?

A
  1. Pale yellow liquid which carries just about everything that needs transporting around your body, majority is water a pale yellow liquid that carries:
  2. RBC, WBC and platlets
  3. Digested food products (e.g. glucose and amino acids) from the gut to all the body cells
  4. Carbon dioxide from body cells to the lungs
  5. Urea from the liver to the kidneys
  6. Hormones (chemical messenger)
  7. Heat energy
  8. Minerals
  9. Vitamins
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16
Q

Describe white blood cells

A
  • Multi-lobed nucleus, cytoplasm and cell membrane
  • Two different types: phagocytes and lymphocytes
  • They also produce anti-toxins to neutralise toxins produced by pathogens
17
Q

What are phagocytes?

A
  1. Phagocytes detect foreign bodies (e.g. pathogens), engulf them and then digest them, they can do this by changing their shape, producing extensions of their cytoplasm called pseudopodia. They inject pathogens
  2. They are non-specific, i.e they attack anything that is foreign
18
Q

What are lymphocytes?

A
  1. Lymphocytes produce soluble proteins that pass into the plasma called antibodies. They release antibodies specific to the pathogen
  2. Pathogens such as bacteria and viruses have antigens on their surface, the antibodies are able to recognise these and so they stick to the surface antigens and destroy the pathogen:
  3. They either cause the bacteria to stick together, so that the phagocytes can ingest them more easily
  4. Act as a ‘label’ on the pathogen so that the phagocyte can more easily recognise the pathogen
  5. Cause bacterial cells to burst open
  6. Neutralise the poisons (toxins) produced by the pathogens
19
Q

What happens to some lymphocytes?

A
  • They may not get involved in killing the microorganism straight away and instead develop into memory cells
  • These cells can remain in the blood for many years making you more immune because if the same microorganism re-infects, the memory lymphocytes can start to reproduce and produce antibodies, so that the pathogen can be dealt with quickly
20
Q

Explain how a vaccine works

A
  1. A vaccine injects a small quantity of a weakened, dead or inactive form of the disease pathogen, these carry the same antigens of those of the disease pathogen.
  2. Once the vaccine has entered your body your lymphocytes will begin to produce the appropriate antibodies
  3. Some of these lymphocytes will remain in the blood as memory cells so if the live pathogens of the same type of disease enters your body, the memory cells (having already been created) can start to reproduce and produce the antibodies sooner and in greater quantity to kill them much faster and in greater numbers, so that the pathogen can be dealt with quickly
21
Q

Describe the right atrium

A
  • The right atrium receives deoxygenated blood from the body through the vena cava
  • The deoxygenated blood moves through to the right ventricle which pumps it into the lungs (via the pulmonary artery)
22
Q

Describe the left atrium

A
  • The left atrium receives oxygenated blood from the veins (though the pulmonary vein)
  • The oxygenated blood then moves through to the left ventricle which pumps it around the whole body (via the aorta)
23
Q

What is the difference in the ventricles?

A
  • The left ventricle has a much thicker wall than the right ventricle as it needs more muscle since it is pumping blood around the hwole body, whereas the right ventricle only has to pump it to the lungs.
  • Blood in the left ventricle is also under higher pressure than the blood in the right ventricle
24
Q

What does pulmonary mean?

A

To do with the lungs

25
Q

What does hepatic mean?

A

To do with the liver

26
Q

What does renal mean?

A

To do with the kidney

27
Q

Why when you exercise does your heart rate increase?

A
  • You muscles need more energy so you respire more
  • You need to get more oxygen into the cells and remove more carbon dioxide, for this to happen your blood needs to flow faster, so your heart rate increase:
    1. Exercise increase the amount of carbon dioxide in your blood
    2. High levels of blood carbon dioxide are detected by receptors in the aorta and carotid artery
    3. These receptors send signals to the brain
    4. The brain sends signals to the heart, causing it to contract more frequently and with more force
28
Q

How does adrenaline affect heart rate?

A
  1. When an organism is threatened (e.g. by a predator) the adrenal glands release adrenaline
  2. Adrenaline binds to specific receptors in the heart. This causes the cardiac muscle to contract more frequently and with more force, so heart rate increases and the heart pumps more blood
  3. This increases oxygen supply to the tissues, getting your body ready for action