B7.2 - transport in mammals Flashcards

1
Q

how does blood travel around the body?

A

Blood is pumped by the heart and travels around the body through blood vessels around the animal

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2
Q

how does oxygenated blood leave the heart?

A

blood leaves the heart through the arteries

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3
Q

how does deoxygenated blood return to the heart?

A

blood returns to the heart by the veins

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4
Q

what ensures that blood travels in one direction?

A

Valves in the heart and veins are used to ensure that the blood does flow back and only moves in a one-way flow.

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5
Q

what happens when blood enters an organ?

A

When blood enters an organ, the arteries divide into smaller arteries called arterioles and further divide into capillaries

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6
Q

what is different in blood flow in the capillaries?

A

In these capillaries the blood moves much slower which allows for the exchange of materials such as oxygen and glucose, carbon dioxide and other wastes between the capillaries and the organ

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7
Q

what is the circulatory system?

A

it is a system of tubes (veins, capillaries, arteries) with a pump (heart) and valves (in heart and veins) to ensure one-way flow of blood.

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8
Q

what happens when blood leaves an organ?

A

Blood leaving an organ is collected in venules and then converge onto larger veins

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9
Q

what animal has a single circulatory system?

A

fish

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10
Q

what happens in the single circulatory system?

A
  1. A heart has two chambers consisting of one atrium (collecting chamber) and one ventricle (ejection chamber)
  2. The heart sends blood to the gills where it is oxygenated
  3. The blood then flows to all the parts of the body in body cells before returning to the heart.
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11
Q

how is the single circulatory system inefficient?

A

This system is inefficient because blood pressure is lost when the blood passes through capillaries in the gills

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12
Q

what is the pathway of blood in the double circulatory system?

A
  1. The heart has four chambers
  2. The blood is first transported to the lungs where it is oxygenated then back to the heart and then to the body and finally back to the heart
  3. The circulation between the heart and the lungs is called pulmonary circulation
  4. The circulation between the heart and the body is called systemic circulation
  5. Advantage of this circulation system is that it can deliver a higher blood flow rate to tissues as there is a high blood pressure to all the major organs of the body.
  6. The heart pumps blood through both circulatory systems to all the major organs of the body and the lungs
  7. The right atrium collects deoxygenated blood from the body and transports it to the right ventricle
  8. The right ventricle pumps deoxygenated blood to the lungs
  9. The left atrium collects oxygenated blood from the lungs and transports it to the left ventricle
  10. The left ventricle pumps oxygenated blood to the body by pushing the blood to the aorta (artery)
  11. The left ventricle has thicker walls than the right because it needs to pump blood to most of the body while the right ventricle fills only the lungs.
  12. The ventricles of the heart in general have thicker muscular walls than the atria to ensure that blood is pumped out of the heart at greater pressure from these chambers compared to the atria.
  13. The septum keeps blood from the right (deoxygenated) and left (oxygenated) sides of the heart from mixing. This is important because the blood in the left ventricle is loaded with oxygen for the rest of the body to use.
  14. To pump blood, the muscle in the walls of the atria and ventricles contracts and relaxes
    The atria walls are the ones to contract first and pump blood into the ventricles.
  15. Then the ventricles contract to pump blood into the arteries.
  16. Valves prevent blood flowing backwards during or after heart contractions.
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13
Q

how many valves does the heart contain?

A

four. two on both sides

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14
Q

what type of valve does the right side of the heart have?

A

The right side has a tricuspid valve (a valve with three flaps) between the atria and the ventricle and a semilunar valve at the entrance of the pulmonary artery

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15
Q

what type of valve does the left side of the heart have?

A

The left side has a bicuspid valve (a valve with two flaps) between the atria and the ventricle and a semilunar valve at the entrance of the aorta

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16
Q

how can the activity of the heart be monitored?

A

ECG (electrocardiogram)
Pulse rate
Heart sound using a stethoscope, ‘lub-dub’ sound caused by the closure of the valves

17
Q

how does the effect of physical activity have on the pulse rate?

A
  • At rest, the heart beats about 70 times a minute (It can vary depending on age, gender and fitness)
  • During exercise, the muscle cells need more energy (hence more oxygen and glucose need to delivered to them for respiration) than usual
    If the muscle does not get enough oxygen, it will start to respire anaerobically, producing lactic acid, which causes muscle fatigue, leading to cramp.
  • Hence physical activity makes the heart beat more quickly and more deeply to increase the circulation of blood to deliver more oxygen and glucose to the muscles
  • Exercise increases the pulse rate, up to 200 beats per minute.
  • After exercise has stopped, the pulse rate gradually drops back to its resting state (the rate can, again, fluctuate depending on the fitness of the person)
18
Q

what is coronary heart disease and what happens when a person has the condition?

A
  • Coronary heart disease occurs when the coronary artery becomes blocked and can’t provide oxygen and glucose (blood) to the muscle tissues in the heart
  • The coronary artery becomes blocked by a buildup of fatty plaques containing cholesterol
  • This leads to that part of the heart being unable to contract, causing a heart attack.
19
Q

what are the possible causes of coronary heart disease?

A
Lack of exercise
Diet high in fat and cholesterol
Diabetes
High Blood Pressure
Genetics
Stress
Smoking
20
Q

how do you prevent coronary heart disease?

A
  • A healthy, balanced diet and exercise can reduce the chances of a person becoming obese. This includes a low intake of saturated fats (it forms atheroma and thrombus)
  • Exercising increases muscle tone, good heart muscle tone leads to an improved coronary blood flow and the heart requires less effort to keep pumping.
21
Q

how is coronary heart disease treated?

A

It can be treated with aspirin, angioplasty and stent as well as by-pass surgery

22
Q

what are the types of blood vessels?

A

Arteries
Veins
Capillaries

23
Q

Arteries: what is the structure and the function?

A

structure:

  1. It has a thick, tough wall to withstand the high pressure (these walls can expand and relax to cause a pulse)
  2. No valve as its not need due to the high pressure
  3. Lumen is quite narrow to maintain high pressure

function:
Transports oxygenated blood throughout the body

24
Q

Veins: what is the structure and the function?

A

structure:
1. Thin walls with very little muscle and fibrous tissues as blood is carried in low pressures
2. Large lumen to reduce resistance to blood flow while also maximising the blood flow
3. Valves are present to prevent blood flow

function:
Transports deoxygenated blood back to the heart

25
Q

Capillaries: what is the structure and the function?

A

structure:
1. Thin permeable wall (only one cell thick) with no muscles to allow diffusion of materials between the capillaries and tissues
2. Lumen is only one blood cell wide to allow the transport of white blood cells in case of an infection while allowing the blood to move slow enough to diffuse materials
3. No valve present as the pressure is still considerably high

function:
1. To diffuse substances between the capillaries and surrounding tissues
2. Oxygen and nutrients diffuse from the capillaries to surrounding tissues
3. Waste products like carbon dioxide and hormones diffused from the tissues to the capillaries

26
Q

what are the different type of blood cells in the blood?

A

Red blood cells
White blood cells
Platelets
Plasma

27
Q

Red blood cells: what is the function?

A
  1. Transporting oxygen using haemoglobin (a red protein that combines with oxygen)
  2. They have no nucleus so they can contain more haemoglobin
  3. They are small and flexible to fit through the capillaries and have a biconcave shape (disc shape) to maximize surface area for oxygen absorption
28
Q

White blood cells : what is the function?

A

Ingesting pathogens (phagocytosis) and producing antibodies

29
Q

Platelets : what is the function?

A

Ingesting pathogens (phagocytosis) and producing antibodies

30
Q

Plasma : what is the function?

A

Transporting blood cells, ions, soluble nutrients, hormones and carbon dioxide