Breathing Mechanisms

Question 1

State the meaning of these keywords:

• lungs,
• ribcage,
• rib muscles,
• diaphragm,
• abdomen,
• thorax,
• trachea,
• bronchi,
• bronchioles
• alveoli.

Answer 1

Lungs- organs for oxygen exchange
Rib cage- bony structure that protects the lungs
Rib muscles- aid breathing by expanding/ contracting the rib cage
Diaphragm- muscle below the lungs that aids breathing
Abdomen- lower torso that is affected by diaphragm movement.
Thorax- chest region housing all vital organs
Trachea- windpipe connecting the throat to the lungs
Bronchi- large airways that is branching into the lungs
Bronchioles- small airways in the lungs
Alveoli- tiny sacs for gas exchange in the lungs

Question 2

What are the processes that happen while inhaling and exhaling-

Answer 2

To inhale-
The inter coastal muscles contract, rib cage moves upwards
At the same time, Diaphragm contracts causing it to flatten/ move down.
These 2 movements cause an increase in the volume of the thorax.
There is a decrease in pressure in the lungs which causes atmospheric air to enter the lungs.

To exhale-
The intercostal muscles relax, ribcage moves downwards
Diaphragm relaxes causing it to return to its doomed shape.
2 movements cause decrease in the volume of the thorax.
An increase in pressure in the lungs causes air to leave the lungs.

Question 3

How can the alveoli help the lungs perform their function?

Answer 3

The alveoli provides a very large surface area in the lungs, and it is also richly supplied with capillaries so that gases easily diffuse in and out of the blood.

Question 4

During breathing, oxygen moves into the blood.
Explain how oxygen moves into the blood.

Answer 4

It moves by diffusion

Question 5

Explain how the human lungs are adapted for efficient
exchange of gases by diffusion. (6 marks)

Answer 5

1- Many alveolis
Which provides a larger surface area

2- capillaries are thin
Which provides a short diffusion path away for oxygen and carbon dioxide.

3- large capillary network around alveoli
Which helps to remove oxygenated blood quickly so that carbon dioxide is brought to the lungs quickly.

4- breathing mechanisms moving air in and out
Which brings in oxygen and removes carbon dioxide

Question 6

During exercise the human body needs to react with the increase demand for energy, what are the number of changes that take place? Hint: exercise

Answer 6

Heart rate increases: more blood flow to the muscles
The rate and depth of breathing increases
Glycogen stored in the muscles is converted back into glucose.

Question 7

What happens when there is insufficient oxygen reaching the muscles?

Answer 7

Energy is transferred by anaerobic respiration.

Question 8

What is anaerobic respiration?

Answer 8

Incomplete breakdown of glucose that causes a build up of lactic acid

Question 9

What is oxygen debt?

Answer 9

The amount of oxygen required from the body for the removal of lactic acid

Question 10

Why is less energy transferred in anaerobic respiration rather than aerobic respiration?

Answer 10

Due to the incomplete breakdown of glucose

Question 11

Why do the muscles feel fatigued during vigorous activity? How can vigorous exercise/ activity affect muscles?

Answer 11

Due to the build up of lactic acid in the MUSCLES
Vigorous exercise causes muscles to not contract efficiently.

Question 12

Write down the chemical and word equation of anaerobic respiration and aerobic respiration-

Answer 12

Glucose —> Lactic acid
C6 H12 O6 —> 2C3 H6 O3

Glucose + oxygen —> carbon dioxide + water
C6 H12 O6 + 6O2 —> 6CO2 + 6 H2O

Question 13

What do plant and yeast cells produce instead of lactic acid?

Answer 13

Carbon dioxide, ethanol

Question 14

State the word equation for anaerobic respiration of yeast/ plant cells-

Answer 14

Glucose —> carbon dioxide + ethanol

Question 15

Where do most of the reactions in aerobic respiration occur?

Answer 15

Michondria

Question 16

How can the energy that is transferred during respiration be used in variety of ways?

Answer 16

To build larger molecules from smaller ones
To enable the muscles to contract in animals
To maintain a steady body temperature in colder temperatures (mammals, birds)
In plants, it can be used to build sugars and nutrients into amino acids which are then built into proteins.

Question 17

Describe the positive pressure systems that are used for ventilation-

Answer 17

PPS causes air to be forced into the lungs
PPS forces air down the trachea and into the lungs.
The volume of air delivered to the patient is carefully monitored.
Once the lungs have been ventilated the air flow cuts off and they’re allowed to deflate

Question 18

Describe the negative pressure systems that are used for ventilation-

Answer 18

NPS causes air to be drawn into the lungs
The air is sucked out from the chamber or shell which causes a negative pressure inside the chamber leading to the air to be drawn in the persons lungs.

Question 19

What are the pros and cons of negative/ positive ventilators?

Answer 19

NPS-
Pros: It is a long term breathing assistant.
No surgical procedure required for this ventilator.
Cons- restricted movement. Disrupted blood flow to the lower limbs and abdomen.

PPS-
Pros- person is able to move. More common nowadays ( easy and quick to use)
Cons- surgically placed tubes are surgically placed and the person needs to be sedated (for the tubes)

Question 20

Give some examples of positive/ negative ventilators?