2 structure and functions in living organisms G (gas exchange in humans)

Question 1

main components of the breathing system:

Answer 1

• ribs
• intercostal muscles
• lungs
• diaphragm
• trachea
• bronchi
• bronchioles
• alveoli
• plural membranes

Question 2

where is the gas exchange system located?

Answer 2

in the thorax (upper part of the body)

Question 3

structure of the trachea:

Answer 3

• tube with connects the mouth and the nose to the bronchi in the lungs
• made of C-shaped rings which prevent the tube from collapsing into itself
• made with goblet and epithilial cells

Question 4

structure of the ribs:

Answer 4

help to protect the organs in the thorax

Question 5

structure of the intercostal muscles

Answer 5

between the ribs, help to connect the bones and are important in moving air in and out of the lungs

Question 6

structure of the diaphragm:

Answer 6

• below the lungs, separating the organs of the thorax and the abdomen
• domed sheet of tissue and muscle is important in moving air into and out of the lungs

Question 7

structure of the bronchi:

Answer 7

• when the trachea splits open it forms the bronchi
• these tubes lead to the lungs
• also surrounded by cartilage rings

Question 8

structure of the bronchioles:

Answer 8

• when the bronchi divide or branch into smaller and smaller tubes
• carry air deep into the thorax

Question 9

structure of the alveoli:

Answer 9

• at the end of each bronchiole
• site of gas exchange

Question 10

structure of the pleural membranes:

Answer 10

• lungs are surrounded by these
• forms a double layer between the lungs and the thorax walls
• in between the membranes there is a thin layer of pleural fluid
• together they form an air tight seal and prevent the lungs from sticking to the thorax wall as they inflate and deflate

Question 11

define ventilation:

Answer 11

the process of moving air into and out of the lungs, moving air relies on differences in air pressure between the lungs and the atmosphere

Question 12

describe the process of inhalation:

Answer 12

1. diaphragm contracts, moving down and flattening, intercostal muscles contract, moving ribcage up and out
2. this causes the volume of the thorax to increase and air pressure in the thorax to fall
3. air pressure in the thorax is now less than atmospheric pressure, causing air to move into the lungs

Question 13

describe the process of exhalation:

Answer 13

1. diaphragm relaxes, moving up and doming, intercostal muscles relax, moving rib cage down and in
2. this causes the volume of the thorax to decrease and air pressure in the thorax to rise
3. air pressure in the thorax is now more than atmospheric pressure

Question 14

how are the alveoli adapted for gas exchange?

Answer 14

1. lots of them- large surface area- increases the rate of diffusion
2. lots of capillaries- high concentration gradient- increases rate of diffusion
3. one cell thick- very short diffusion distance- faster diffusion

Question 15

what is present in tobacco smoke?

Answer 15

carbon monoxide in tobacco smoke- permanently binds to haemoglobin- reduces the amount go oxygen in the blood

Question 16

what effect do the chemicals in the tobacco smoke have on cilia?

Answer 16

• destroy and reduce the number of cilia
• increase mucus production
• mucus cannot be moved out of the airways quickly so builds up
• this causes smokers cough and increases the risk of infections
• bronchitis is a disease resulting from the build- up of infected mucus in the bronchi and bronchioles

Question 17

what effect do the chemicals in the tobacco smoke have on alveoli?

Answer 17

• damages them
• alveoli walls freak down in places and fuse together forming larger, irregular air spaces
• decreases the surface area for gas exchange
• so less oxygen diffuses into the blood
• this disease is called emphysema

Question 18

what does smoking increase your risk of?

Answer 18

• coronary heart disease
• lung cancer

Question 19

Practical: The Effect of Exercise on Breathing:

Answer 19

1. count the number o breaths someone takes in 30 seconds at rest
2. ask them to jog or five minutes
3. calculate the number of breaths in the first 30 seconds straight after exercise
4. limewater to calculate the release of CO2- inhaled air stays colourless, exhaled air turns milky white
5. control age, gender, fitness