6.4

Question 1

Why do we need a ventilation system?

Answer 1

• Large organism: small organisms can use simple diffusion while large organisms need respiratory system + circulatory system for delivery of nutrients + removal of waste
• land borne: dry skin, cannot diffuse gas through skin (gases need moist surfaces to diffuse
• need to maintain large concentration gradient btwn alveoli and blood

Question 2

Draw an alveoli (w/movement of gases) ANOTATE!

Question 3

Type 1 pneumocyte

Answer 3

• single epithelium layer
• flattened cell 0.15 um thick
• capillaries also 1 cell thick
• small distance for O2 and CO2 to travel during gas exchange.
  Role: provide a thin layer for gases to pass through

Question 4

Type 2 pneumocyte

Answer 4

• rounder cells in lining of alveoli (make up 5% of alveoli)
• secrete fluid (surfactant) which coats inner surface of alveoli
• moisture aids in diffusion of gases
• surfactant reduces surface tension + prevents sides of alveoli from sticking together
• premature babies can suffer from insufficient pulmonary surfactant

Question 5

Trachea

Answer 5

• Rings of cartilage
• keeps open even during low pressure

Question 6

Bronchi

Answer 6

• rings of cartilage

Question 7

Bronchioles

Answer 7

• smooth muscle fibres in wall
• allows width of airway to change

Question 8

Alveoli (purpose)

Answer 8

Gas exchange

Question 9

Diaphragm

Answer 9

• controls vol. of chest capacity
• muscle

Question 10

Muscles during ventilation

Answer 10

• contracting muscles: get shorter
• relaxing muscles: lengthen passively
• muscles can only move in one direction
• muscles alternate btwn relaxing and contracting (antagonistic pairs)

Question 11

Inspiration

Answer 11

• decrease in pressure
• volume increase
• rib cage moves up and ouward
• external intercoastal muscles contract
• internal intercoastal muscles relax
• diaphragm: contracts
  Abdominal muscles: relax

Question 12

Expiration

Answer 12

• increase in pressure
• decrease in volume
• rib cage moves down and inward
• external intercoastal muscles: relax
• internal intercoastal muscles: contract
• diaphragm: relaxes
• abdominal muscles: contract

Question 13

Causes of lung cancer

Answer 13

• smoking (86% of mutagens)
• second hand smoking
• air pollution
• family history of lung cancer
• past cancer treatment
• radon gas: radioactive gas that leaks out of certain rocks
• asbestos, silica: inhaling particles

Question 14

Consequences of smoking

Answer 14

• difficulties breathing
• persistent cough
• chest pain
• loss of appetite
• fatigue
• weight loss
• 15% survival rate for 5 years
• lung can be removed surgically if tumour is discovered
• those cured from lung cancer likely suffer longer term effects

Question 15

Causes of emphysema

Answer 15

• smoking
• long history of chest infection
• inflammatory response in the lungs
• air pollution

Question 16

Consequences of emphysema

Answer 16

• WBC release protease: breaks down connective tissues; destruction of small airways and alveoli, breakdown of capillaries, insufficient ventilation (low SA:vol. Ratio, formation of air pockets), inefficient gas exchange as a result of low O2 levels
• not curable, but have treatments which can help manage disease
• difficulty breathing
• loss of appetite
• cough
• weight loss

Question 17

Know the ventilation graph

Answer 17

• tidal vol.
• inspiratory reserve vol.
• exploratory reserve vol.
• total lung capacity
• vital capacity
• function residual capacity