The Respiratory System

Question 0

What is the purpose of ventilation

Answer 0

The purpose of ventilation is to get oxygen in and carbon dioxide out

Question 1

What is ventilation?

Answer 1

Ventilation is the process of getting air in and out of animals.

Question 2

What is gas exchange?

Answer 2

Gas exchange is the process of getting oxygen into the bloodstream and carbon dioxide out.

Question 3

What is respiration?

Answer 3

Respiration is the process where cells produce energy. Typically this involves glucose and oxygen

Question 4

What are the two types of respiration

Answer 4

Aerobic 
C6H12O6 + 6 O2 --> ATP + 6 CO2 + 6H2O
Anaerobic 
lactic acid fermentation
A) glucose --> lactic acid (lactate) + 2 ATP 
Alcoholic fermentation
B) glucose --> ethanol + CO2 + 2 ATP

Question 5

What is the structure of the respiratory system?

Answer 5

Trachea
Bronchus (with rings of cartilage)
Secondary and tertiary bronci
Bronchioles
Alveoli
Pleural fluid (inner and other membrane)
Diaphragm

Question 6

What is the role of the rings of cartilage?

Answer 6

To prevent the airways from collapsing during inhalation

Question 7

What happens during inhalation?

Answer 7

External intercostal muscle contract.
Ribcage moves upwards and out wards
Diaphragm contracts and moves downwards
The volume of thoracic cavity increases
Thus pressure decreases
Air is drawn into lungs, and lungs inflate.

Question 8

What happens in non-forced exhalation?

Answer 8

External intercostal muscles relax
Ribcage moves downwards and inwards due to elastic connective tissue surrounding the ribs
Diaphragm also relaxes which allows the diaphragm to move up into a more domed position, hence volume of thoracic cav. Decreases and pressure increases. Air is forced out of the lungs and they deflate.

Question 9

What happens with forced exhalation

Answer 9

The key difference is that internal intercostal muscles and abdominal muscles now contact reducing the volume of the thoracic cavity even more, e.g, speaking, blowing out candles, etc.

Question 10

Describe the nervous control of inhalation

Answer 10

When carbon dioxide levels reach a critical point, the inspiratory centre sends impulses along the intercostal nerve to the external intercostals and along the phrenic nerve to the diaphragm. These muscle groups then contract to facilitate inhalation/inspiration
(See diagram)

Question 11

Describe the nervous control of non-forced exhalation

Answer 11

Stretch receptors are stimulated at peak inhalation period.
Impulses sent to the exhalation centre via the vagus nerve EC inhibits ic
Inhalation centre stops stimulating diaphragm and external intercostals
Exhalation begins
(See diagram)

Question 12

Describe the nervous control of forced exhalation

Answer 12

The same as non-forced

Additionally, EC stimulates internal intercostals to contract

Question 13

What is the composition of inspired air?

Answer 13

Oxygen - 20.95%
Carbon dioxide - 0.04%
Nitrogen - 79.01%

Question 14

What is the composition of alveolar air?

Answer 14

Oxygen - 13.80
Carbon dioxide - 5.50
Nitrogen - 70.70

Question 15

What is the composition of expired air?

Answer 15

Oxygen - 16.40
Carbon dioxide - 4.00
Nitrogen - 79.60

Question 16

What pressure gradient do gases diffuse from?

Answer 16

Gases diffuse from a higher partial pressure to a lower partial pressure

Question 17

How thick is the alveolus membrane?

Answer 17

One cell layer thick

Question 18

What are the three factors affecting diffusion and how do they do this?

Answer 18

Membrane thickness: thin membrane allows diffusion to occur more readily
Difference in p.p(diffusion gradient) /conc.: the greater the diff. In conc. the greater the rate of diffusion
Surface area: the greater the surface area, the greater the rate of diffusion.

Question 19

What is ficks law?

Answer 19

Rate of diffusion is proportional to the surface area x the diffusion gradient, divided by the membrane thickness.