1.2 The Respiratory System

Question 1

What is the passage of air?

Answer 1

Nose, larynx, trachea, bronchi, bronchioles, alveoli

Question 2

What is the structure of the alveoli?

Answer 2

One cell thick walls that allow for a short diffusion pathway
Good blood supply due to network of capillaries around
Huge surface area that allows for a greater uptake of O2

Question 3

Lung Volumes

Question 4

What is Tidal volume?

Answer 4

Volume of air breathed in or out per breath

Question 5

What is Inspiratory reserve volume?

Answer 5

Volume of air that can be forcibly inspired after a normal breath

Question 6

What is Expiratory reserve volume?

Answer 6

Volume of air that can be forcibly expired after a normal breath

Question 7

What is residual volume?

Answer 7

Volume of air that remains in the lungs after maximum expiration

Question 8

What is minute ventilation?

Answer 8

Volume of air breathed in or out per minute

Question 9

Gaseous Exchange

Question 10

What happens at gaseous exchange at the alveoli?

Answer 10

PP of O2 in alveoli is higher than PP in capillary
Because O2 removed by working muscles so concentration in blood is low, so is PP
Bigger concentration gradient, faster diffusion
O2 diffuse from alveoli into blood until pressure is equal.

Question 11

What happens at gaseous exchange at the muscles?

Answer 11

PP O2 has to be lower at the tissues than in blood so diffusion can occur
Capillary membrane surrounding muscle the PP O2 is lower that blood
Low PP allows O2 to diffuse from blood into muscle until equilibrium is reached
PP CO2 blood is lower than in tissues so diffusion occurs & CO2 moves into blood to be transported to lungs.

Question 12

What is the Neural control?

Answer 12

Brain
Nervous System

Question 13

What is Chemical control?

Answer 13

Blood Acidity Levels

Question 14

How does Breathing increase?

Answer 14

Blood acidity is high
The brain is informed
Sends impulses through NS

Question 15

What does the Sympathetic NS do?

Answer 15

Prepare body for exercise, increases breathing rate

Question 16

What does the Parasympathetic NS do?

Answer 16

Lower Breathing rate

Question 17

How does respiratory rate increase?

Answer 17

Increase in CO2 on blood stimulates respiratory centre

Question 18

What are the 2 main systems?

Answer 18

Inspiratory centre
Expiratory centre

Question 19

What is the Inspiratory centre?

Answer 19

Responsible for inspiration & Expiration
Sends nerve impulses via phrenic nerve to inspiratory muscles to cause them to contract
Takes 2 seconds then impulses stop & passive expiration occurs due to elastic recoil of lungs

Question 20

What is the Expiratory centre?

Answer 20

Stimulates the expiratory muscles during exercise

Question 21

What happens to Blood acidity during exercise?

Answer 21

Increases as a result of increase in plasma concentration of CO2 & lactic acid
Detected by chemoreceptors, sends to inspiratory centre to increase ventilation until blood acidity returns back to normal

Question 22

How does blood acidity return back to normal?

Answer 22

Respiratory centre sends impulses down the phrenic nerve to stimulate more inspiratory muscles
Resulting in rate, depth and rhythm of breathing rate

Question 23

How does smoking impact the respiratory system?

Answer 23

Cause irritation of the trachea and Bronchi
Increases breathlessness caused by swelling and narrowing of the lungs.