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Biology > Gas Exchange in Humans > Flashcards

Gas Exchange in Humans Flashcards

1
Q

The larger an organism is….. What does this mean in terms of diffusion

A

The smaller its surface area to volume ratio. This means that simple diffusion will not be fast enough to supply all its needs and the organism would die.

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2
Q

How do larger organisms get past the problem of diffusion being slow? Which system is an example that helps this?

A

They have specially adapted gas exchange surfaces which increase the effectiveness of gas exchange between the organism and the outside world. Human respiratory system often helps this

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3
Q

Definition of gas exchange

A

The diffusion of oxygen into the blood and the carbon dioxide out of the blood

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4
Q

Where does gas exchange take place in humans?

A

It takes place in the alveoli of the lungs

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5
Q

Difference between respiration and breathing

A

Respiration is the release of energy from glucose using oxygen which produces carbon dioxide as a waste product - it takes place in every living cell.

Breathing is the movement of gases into and out of the lungs. It is the way in which the oxygen needed for respiration enters the body and carbon dioxide leaves the body.

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6
Q

Where is the respiratory system located?

A

It is located in the chest cavity known as the thorax

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7
Q

Labelled diagram of respiratory system

A

On OneNote LOOOOKKKK

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8
Q

Bronchi

A

The two tubes that the trachea splits into

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9
Q

Diaphragm

A

A muscular sheet at the bottom of the thorax involved in ventilation

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10
Q

Trachea

A

Transmits air from outside to to the lungs

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11
Q

What does it mean by rings of cartilage?

A

It means that it is flexible, but doesn’t collapse when breathing out

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12
Q

Alveoli

A

Air sacs where gas exchange occurs

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13
Q

Ribs

A

Bones that surround the lungs - act as protection and involved in ventilation

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14
Q

Bronchioles

A

The smaller tubes that the bronchi split into

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15
Q

Intercostal muscles

A

The muscles found between the ribs involved in ventilation

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16
Q

Pleural membranes

A

Moist membranes between the inside of the thorax and lungs that provide lubrication to prevent the lungs from ‘sticking.’

17
Q

Diagram of the alveolus to show the adaptations of the alveoli for gas exchange

A

On OneNote -LOOOKKKK

18
Q

How is alveoli adapted for gas exchange?

A

The alveoli has a spherical shape which increases the surface area over which gas exchange can occur so that many gases can pass into the blood stream at once.

The cells lining the alveoli are one cell thick so there is only a short diffusion distance which means that the gases do not have far to travel so that they can be exchanged quickly.

There is a rich network of capillaries surrounding each alveolus. The blood flow maintains a steep concentration gradient for diffusion of gases by continuously delivering excess carbon dioxide to the alveolus and taking away the oxygen to deliver to the respiring cells.

Ventilation also helps to maintain this steep concentration gradient by constantly removing carbon dioxide and delivering oxygen.

They have moist surfaces to allow gases to dissolve so that they can diffuse faster.

19
Q

Practical: investigate breathing in humans including the release of carbon dioxide

A

Two boiling tubes filled with limewater connected by rubber tubings in which Tube A air enters and Tube B air leaves and in the middle is where your mouth goes.

The limewater changes from a colourless solution to a milky colour when carbon dioxide is bubbled through it.

As the person breathes in, air is drawn through Tube A and bubbles through the limewater. As the concentration of carbon dioxide in inhaled air is low, there is no colour change in the limewater in Tube A.

However, as the person breathes out, exhaled air passes through tube B. This air contains more carbon dioxide than inhaled air so the limewater turns milky.

20
Q

Ventilation definition

A

The movement of gases into and out of the lungs known as breathing. It involves inhalation and exhalation.

21
Q

What does ventilation require?

A

It requires pressure changes to occur in the lungs so that the air can be forced in and out of the alveoli

22
Q

How are these pressures brought about? Explain where these are

A

It is brought about by the movement of two sets of muscles - the diaphragm and the intercostal muscles.

The diaphragm is a sheet of muscle that separates the thorax from the abdomen.

The intercostal muscles lies between the ribs. The external intercostal muscles lie on the outside of the ribcage. The internal intercostal muscles lie on the inside of the ribcage.

23
Q

During gentle breathing, which muscles are involved and what about during exercise and why

A 
During gentle breathing, the diaphragm is involved
During exercise (breathing hard), the intercostal muscles start to work to move the ribs and assist with breathing
24
Q

What evens happen during inhalation? 6 marks

A
  1. The external intercostal muscles contract, making the ribs move upwards and outwards
  2. The diaphragm contracts and flattens in shape
  3. These changes cause the volume in the thorax to increase
  4. This causes the pressure in the thorax to decrease
  5. Atmospheric pressure is now higher than the pressure in the thorax
  6. This pressure difference causes air to be drawn into the lungs
25
Q

What events happen during exhalation? (7) 7th mark for saying what happens to the intercostal muscles when breathing hard

A
  1. The external intercostal muscles relax allowing the ribs to move back inwards and downwards which also pushes against the lungs. When breathing harms the internal intercostal muscles will contract to help the ribs move back down and in faster.
  2. The diaphragm relaxes and returns to its domed shape, pushed up by the liver and the stomach. It pushes up on the lungs from below
  3. These changes cause the volume of the thorax to decrease
  4. This causes the pressure in the thorax to increase
  5. The pressure in the lungs is now greater than atmospheric air
  6. This pressure difference causes air to be forced out of the lungs
26
Q

How does air move? From what area to what area?

A

Air moves from an area of high pressure to an area of low pressure

27
Q

What happens to our muscles when we exercise? How do we do this? What do we need?

A

When we exercise, our muscles contract. This requires energy. The more movement needed, the more energy they need. They get this energy from respiration so they need a constant supply of oxygen and glucose.

28
Q

What can the muscles do so that we can exercise ?

A

Muscles can store glucose in the form of glycogen. This can be converted back into glucose for respiration when needed.

29
Q

How is the oxygen supplied in order to exercise?

A

It is supplied by breathing and transported into the blood to the working muscles

30
Q

Is anaerobic respiration less efficient than aerobic respiration? If so why?

A

Yes anaerobic is less efficient. This is because the glucose is not completely down into carbon dioxide and water but instead forms another molecule called lactic acid. This means less energy is released.

When muscles respire anaerobically, they often get fatigued which means they can’t contract efficiently. This is caused by the build up of lactic acid. This lactic acid must be removed by the blood from the muscles and broken down into carbon dioxide and water. This need oxygen. The amount of oxygen needed to do this is the oxygen debt also known as the EPOC. EPOC is the reason why your breathing rate remains high after you have stopped exercising.

The fitter you are, the quicker the recovery will be, the soon the lactic acid will be converted into carbon dioxide and water and the sooner you stop panting.

31
Q

What happens to your breathing rate when you exercise and why?

A

During exercise, you are doing more physical work and so MORE oxygen needs to be given to the muscles by the blood. The more exercise you do, the more your breathing rate will INCREASE as its bringing more oxygen into your lungs so the heart can pump it to the muscles. This means that THE RATE AND DEPTH OF YOUR BREATHING INCREASES which makes sure more oxygen is absorbed into the blood and MORE CO2 is removed. You need more oxygen so you can respire more for respiration - this means the oxygen is used for respiration.

32
Q

What happens to your heart rate when you exercise and why?

A

When you exercise, your heart rate INCREASES so that MORE blood is pumped to the muscles MORE quickly. This is so it can supply more oxygen for respiration. It also increases because it allows waste products (e.g. carbon dioxide) to be removed. You also need glucose for respiration and so it increases.

33
Q 
The effect of nicotine (a chemical in tobacco smoke) on humans
What is it?
What does it specifically affect?
What does it increase?
What effects does it cause?
What can it lead to?
A

Nicotine is a highly addictive drug that affects the central nervous system acting both as a stimulant and a relaxant.

As its so addictive, it causes unpleasant withdrawal effects if they do not smoke regularly.

Nicotine increases the heart rate and narrows the blood vessels, causing high blood pressure.

This can lead to heart disease

34
Q

The effect of tar
What is produced to trap dirt and microbes and what moves this?
How does this affect you when smoking?
What can it lead to? Which disease?
Over a long period of time, what can it lead to? Which disease?

A

Cells in the lining of the respiratory tract produces spicy mucus to trap dirt and microbes. Cells with tiny hair like parts, called cilia, normally move this mucus out of the lungs to the back of the throat where it is swallowed and destroyed by the HCL.

The tar forms a black sticky substance in the lungs which coats the cilia making them unable to move to clear the mucus containing dust and micro-organisms.

The mucus therefore collects in the lungs and leads to a persistent cough and recurrent infections. This is responsible for the disease bronchitis.

Over a long period of time, this continuous coughing damages the alveoli. The walls between adjacent alveoli break down making large individual alveoli with a reduced surface area. This causes a disease called emphysema and the patient can’t get enough oxygen for any activity.

35
Q

Carcinogenic Chemicals

What does this cause?

A

Some chemicals in tar are carcinogenic which means they can cause random mutations to occur. They are a rare change in DNA which can lead to cells starting to divide forming a tumour. This is cancer.

36
Q 
Carbon monoxide
What does it cause? As well as nicotine
Haemoglobin?
Increase in what?
What about when you are pregnant
A

Causes an increase in blood pressure

It combines with haemoglobin in red blood cells in preference to oxygen so not enough oxygen can be carried to respiring cells which then die off. Amputation may be necessary.

It causes an increase in heart rate to compensate for the reduced oxygen carrying capacity of the blood which can lead to heart disease.

It may pass to an unborn baby if a woman smokes while pregnant. This leads to low birth weight babies which can lead to an increased risk of coronary heart disease and heart attack.

37
Q

Chemicals causing cholesterol to be released into the blood

What can the cholesterol do?
What can be formed? In which two ways can this do?

A

The cholesterol can attach to the lining of blood vessels that have been irritated by smoke chemicals. This can cause the lining of the blood vessel to become thicker which reduces blood flow and can cause clots to form.

If the clot travels to the brain, a stroke may occur.

If the clot occurs in the blood vessels supplying the heart, it reduces the amount of oxygen and glucose able to be supplied to the heart muscle which means that the heart muscle does not have enough oxygen for respiration. This leads to death of the heart muscle and a heart attack occurs.

38
Q

Design an experiment to show the effect of exercise

A

Independent variable -
Dependent variable -
Control variable -

Biology (10 decks)

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