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B3 > B3 > Flashcards

B3 Flashcards

1
Q

How are exchange surfaces adapted?

A
  • thin so substances only have a short diffusion pathway
  • large surface area so more substances can diffuse at once
  • lots of blood vessels to get stuff into and out of blood quickly
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2
Q

When do guard cells close the stomata ?

A

If the plant is losing water faster than it is being replaced by the roots

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3
Q

How does the flattened shape of a leaf increase rates of diffusion?

A

It increases the area of the exchange surface so that it’s more effective

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4
Q

How do the walls of the cells inside a leaf contribute towards diffusion?

A

They form another exchange surface

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5
Q

How do air spaces in a leaf contribute towards diffusion?

A

It increases the area of this surface so there’s more chance for carbon dioxide to get into the cells

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6
Q

When is evaporation quickest?

A

In hot, dry and windy conditions

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7
Q

Where are the lungs located ?

A

In the thorax

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8
Q

How are Villi adapted ?

A
  • increase surface area in small intestine so they can absorb more nutrients which then diffuse into bloodstream
  • microvilli further increase surface area
  • capillaries are one dell thick so allow diffusion to happen at a faster rate
  • villi can sway side to side so nutrients can pass through and they can also absorb nutrients around them
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9
Q

What is inspiration ?

A

When pressure outside the lungs is greater than inside (air will move in)

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10
Q

What is expiration?

A

When pressure inside is greater than outside (air is forced out)

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11
Q

Explain the steps of inspiration

A
  1. External intercostal muscles contract, intercostal muscles relax
  2. Rib cage is pulled up and out , increases volume of chest
  3. Diaphragm moves down as it contracts
  4. Increases volume in the thorax and reduces pressure inside
  5. Air is forced into the lungs
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12
Q

Explain expiration

A
  1. Intercostal muscles muscles and diaphragm relaxes, diaphragm moves up
  2. Thorax volume decreases
  3. Pressure increases, so air is forced out
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13
Q

What are the bronchi connected to?

A

The lungs

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14
Q

Where does gas exchange in the lungs take place?

A

In the alveoli

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15
Q

What is the job of the lungs?

A

Transfer oxygen to the blood and to remove waste carbon dioxide from it
To do this the lungs contain alveoli where gas exchange takes place

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16
Q

How do root hair cells take in minerals?

A

Through active transport. The plant can absorb minerals from s dilute solution against a concentration gradient

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17
Q

How does active transport happen in the body?

A

Glucose is taken from the gut and from the kidney tubules

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18
Q

When is active transport used in the gut?

A

When there is a low concentration of nutrients in the gut and a high concentration in the blood

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19
Q

What do phloem tubes do?

A

They transport food substances made in the leaves to growing regions and storage organs of the plant (both directions)

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20
Q

What do xylem tubes do?

A

They take water and minerals from the roots to the stem and leaves

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21
Q

What is the definition of transpiration?

A

The movement of water through a plant caused by the evaporation and diffusion of water from inside the leaves

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22
Q

Why is there a constant transpiration stream In a plant?

A

Water is taken out of the plant by evaporation and diffusion so the water needs to be replaced by the xylem bringing water up through the plant from the roots

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23
Q

What is a potometer?

A

It is used for measuring the rate of photosynthesis and the rate of water upstate of a leafy plant shoot

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24
Q

How does blood get into the heart?

A

Blood flows into the atria of the heart from the vena cava and pulmonary vein

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25
Q

What do the atria do?

A

The contract, pushing the blood into the ventricles

26
Q

What do the ventricles do ?

A

They contract, pushing blood into the pulmonary artery and the aorta and out of the heart

27
Q

What do capillaries do ?

A

They are involve in the exchange of materials at the tissues

28
Q

What are the features of arteries?

A
  • strong and elastic walks to withstand high pressures

- thick layers of muscle and elastic layers to make them strong and to allow them to stretch and spring back

29
Q

What are the features of capillaries?

A
  • Carry bloody really close to every cell in the body to exchange substances with them
  • permeable walls so substances can diffuse in and out
  • take away waste
  • walls are one cell thick, increases rate of diffusing by increasing distance
30
Q

What are the features of veins?

A
  • not as thick walls as blood pressure in veins isn’t as high
  • bigger lumen to help blood flow
  • valves to prevent backflow of blood
31
Q

What happens to Haemoglobin in the lungs?

A

It combines with oxygen to form oxyhaemoglobin

32
Q

What do platelets do?

A

-help blood clot

33
Q

What can a lack of platelets cause? What do they stop?

A
  • a lack can cause excessive bleeding and bruising

- they stop blood pouring out and stop microorganisms getting in

34
Q

What is plasma ?

A

A liquid that carries dissolved substances around the body

35
Q

What substances can plasma carry?

A

-red + white blood cells, glucose, amino acids, carbon dioxide, urea, hormones, antibodies + antitoxins

36
Q

What is oxygenated blood?

A

Red blood cells that have oxygen in them from the lungs

37
Q

What does an artificial blood product do ?

A

Replace the need for a blood transfusion

38
Q

What are the advantages of an artificial heart ?

A
  • reduces the need for a donor heart

- they’re not rejected by body’s immune system

39
Q

What are the disadvantages of an artificial heart?

A
  • surgery can lead to bleeding and infection
  • they don’t work as well as natural ones
  • parts of the heart could wear out
  • blood doesn’t flow smoothly through it which could lead to blood clots and strokes
40
Q

What is coronary heart disease?

A

When the arteries that supply the blood the the muscle of the heart get blocked

41
Q

What is homeostasis ?

A

The maintenance of a constant internal environment

42
Q

What are the 6 things that bare er to be controlled in the body ?

A
  1. Body temperature
  2. Water content
  3. Ion content
  4. Blood sugar levels
  5. Carbon dioxide levels
  6. Urea
43
Q

What does the thermoregulatory centre in the brain contain?

A

Receptors that are sensitive to the temperature of the blood flowing through the brain

44
Q

What happens when you’re too hot?

A
  • hairs lie flat
  • sweat is produced
  • blood vessels supplying the skin dilate (vaso-dilation) so more blood flows close to the surface of the skin which makes it easier for heat to be transferred from blood to the environment
45
Q

What happens when you’re too cold?

A
  • hairs stand up to trap an insulating layer of air
  • no sweat is produced
  • blood vessels construct to close off skins blood supply
  • shivering (muscles contract) which needs respiration, which releases some energy to warm the body
46
Q

What are the 3 main jobs of the kidney?

A
  1. Removal of urea from the blood
    2.adjustment of ions in the blood
    3 adjustment of water content of the blood
47
Q

Where is urea produced ?

A

The liver

48
Q

Where is urea excreted?

A

The bladder

49
Q

How is water lost from the body ?

A
  • urine
  • sweat
  • in the air we breathe out
50
Q

What happens on a cold day if you don’t sweat?

A

You produce more urine which will be pale and dilute

51
Q

What happens on a hot day when you sweat a lot?

A

You’ll produce less urine which will be dark coloured and concentrated

52
Q

What is insulin produced by?

A

The pancreas, which causes glucose to change to glycogen

53
Q

What happens when glucose falls during exercise ?

A

Glycogon is released and converted back to glycogen

54
Q

Describe filtration

A

Blood passes through capillary at start of the nephron
Small molecules are filtered out and pass into nephron tube
The small molecules are glucose, urea ions and water

55
Q

Describe reabsorption

A

The kidneys must reabsorb molecules which are needed
This includes glucose, the right amount of water and ions
Water takes place by osmosis
Glucose and mineral ions =active transport

56
Q

Describe the formation of urine

A

Molecules which are not reabsorbed continue along nephron tube as urine which then passes down to bladder

57
Q

What are the waste products in dialysis ?

A

Urea, excess salt

58
Q

What controls blood glucose levels?

A

Insulin and glucagon

59
Q

What is added if blood glucose level is too high/low?

A 
HIGH= insulin
LOW= glucagon
60
Q

How can diabetes be controlled?

A
  • limiting intake of foods rich in simple carbohydrates
  • regular exercise to lower blood glucose level
  • insulin therapy , makes sure glucose is removed from the blood quickly once food had been digested

B3 (1 decks)

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