Gas Exchange, Gas Transport And Control Of Respiration

Question 1

Identify a typical disease for restrictive respiratory problems.

Answer 1

-fibrosis of the lung; actually respiratory disorder syndrome.

Question 2

Identify a typical disease for obstructive respiratory problems.

Answer 2

-asthma or emphysema.

Question 3

How would a restrictive respiratory disease affect a persons breathing and more particularly their dynamic lung measurements?

Answer 3

Decrease in lung capacity.

Question 4

How would an obstructive respiratory disease affect a persons breathing and more particularly their dynamic lung measurements?

Answer 4

Airways narrowed or collapsing on expiration.

Question 5

Explain obstructive lung disease.

Answer 5

Generally have difficulty in getting the air out from their lungs on expiration. Diagnosed by measuring the FEV1sec/FVC ratio (FEV1%).
-FEV1sec is low, but FVC is normal.

Question 6

Explain restrictive lung disease.

Answer 6

Generally have difficulty in getting a full amount of air into their lungs on inspiration. On expiration there is no airway collapse. Both FEV1sec and FVC and decreased.

Question 7

At vertebral level T4/T5 the trachea divides into?

Answer 7

Left and right primary bronchi.

Question 8

Which lung are foreign objects more likely to be inhaled into?

Answer 8

Right lung as its primary bronchi intro is more vertical and wider than left.

Question 9

How many secondary bronchi (lobar) are there in each lung?

Answer 9

• R lung: 3 (one to each of the three lobes).

- L lung: 2 (one for each of the two lobes).

Question 10

Define the term bronchopulmonary segment.

Answer 10

Segment of lung tissue which is served by its own tertiary bronchus, artery/vein and lymphatics.

Question 11

Approximately how many bronchopulmonary segments are there in each lung?

Answer 11

10 per lung (some books: 10R and 8L).

Question 12

Where does the primary bronchus supply air?

Answer 12

The lung.

Question 13

Where does the secondary bronchus supply air?

Answer 13

The lobe.

Question 14

Where does the tertiary bronchus supply air?

Answer 14

The bronchopulmonary segment.

Question 15

Where does the terminal bronchiole supply air?

Answer 15

The lung lobule.

Question 16

If there is no cartilage present in the bronchioles, what holds the airway open?

Answer 16

Smooth muscle.

Question 17

The last part of the conducting portion is known as the?

Answer 17

Terminal bronchiole.

Question 18

What distinguishes a terminal bronchiole from a respiratory bronchiole?

Answer 18

The respiratory bronchiole has alveoli budding directly off it.

Question 19

What is the origin of the pulmonary artery?

Answer 19

Right ventricle via pulmonary trunk.

Question 20

What is the origin of the bronchial artery?

Answer 20

The aorta.

Question 21

What type of blood does the bronchial artery carry?

Answer 21

Oxygenated.

Question 22

What is the function of the bronchial artery?

Answer 22

To take oxygenated blood from aorta to supply all lung tissue (except alveoli).

Question 23

What is the function of pneumocyte type 1/alveolar cell type 1?

Answer 23

Gas exchange.

Question 24

What is the function of pneumocyte 2/alveolar cell type 2?

Answer 24

Secrets surfactant.

Question 25

What is the function of surfactant?

Answer 25

Decrease surface tension.

Question 26

How does surfactant aid expiration?

Answer 26

Prevents alveolar collapse.

Question 27

A third type of cell wanders along alveolar surfaces removing dust, debris and bacteria. These are called?

Answer 27

Alveolar macrophages (dust cells).

Question 28

Small alveolar pores connect adjacent alveoli. What is their function?

Answer 28

Equalise pressure between alveoli.

Question 29

Why is only a small percentage of O2 normally carried by blood plasma?

Answer 29

O2 dissolves very poorly in solution.

Question 30

Another O2 binding protein which is similar to haemoglobin is found in muscle called?

Answer 30

Myoglobin.

Question 31

What is the driving force for the transport of O2 and CO2 across the respiratory membrane?

Answer 31

Partial pressures.

Question 32

How is CO2 normally dissolved in the blood? What are the relative percentages?

Answer 32

- dissolved: 7%. - bound to haemoglobin: 23%. - as the bicarbonate ion: 70%.

Question 33

When CO2 binds to haemoglobin, what compound is formed?

Answer 33

Carbaminohaemoglobin.

Question 34

When carbon monoxide (CO) binds to haemoglobin, what compound is formed?

Answer 34

Carboxyhaemoglobin.

Question 35

Why is CO such a poisonous substance?

Answer 35

It competes with, and displaces O2 from haemoglobin.

Question 36

On a oxygen-Hb dissociation curve what happens to the %O2 Hb saturation at a PO2 of 40mm Hg for the right shifted curve?

Answer 36

Decreases.

Question 37

On a oxygen-Hb dissociation curve what happens to the %O2 Hb saturation at a PO2 of 40mm Hg for the left shifted curve?

Answer 37

Increases.

Question 38

On a oxygen-Hb dissociation curve which shift facilitates O2 delivery to the tissues?

Answer 38

Right shift.

Question 39

On a oxygen-Hb dissociation curve which shift facilitates O2 binding to haemoglobin?

Answer 39

Left shift.

Question 40

Would an increased tissue metabolism be associated with an increase or decrease in pH?

Answer 40

Decrease.

Question 41

Would an increased tissue metabolism be associated with an increase or decrease in temperature?

Answer 41

Increase.

Question 42

Would an increased tissue metabolism be associated with an increase or decrease in PCO2?

Answer 42

Increase.

Question 43

What sensory mechanisms exist in the body to monitor blood gases?

Answer 43

Chemoreceptors.

Question 44

Where are the peripheral chemoreceptors located?

Answer 44

- carotid (arotid sinus). | - aortic (aortic arch) bodies.

Question 45

Where are the central chemoreceptors located?

Answer 45

In the medulla of the brain, close to the respiratory centres.

Question 46

What specific chemicals do the peripheral chemoreceptors monitor?

Answer 46

H+, CO2 and O2.

Question 47

What body fluid are the peripheral chemoreceptors bathed by?

Answer 47

Arterial blood.

Question 48

What specific chemicals do the central chemoreceptors monitor?

Answer 48

H+ derived from blood CO2.

Question 49

What body fluid are the central chemoreceptors bathed by?

Answer 49

CSF.

Question 50

Why are central chemoreceptors so sensitive to blood PCO2 levels?

Answer 50

CSF contains no buffers to contain any change in pH. As soon as CO2 diffuses into the CSF, it is quickly converted to H+ and stimulates the chemoreceptors.

Question 51

Why are peripheral chemoreceptors not very sensitive to PO2 levels?

Answer 51

They are monitoring arterial blood which normally has a PO2>98mmHg.

Question 52

When do peripheral chemoreceptors respond to changing PO2 levels to stimulate respiration?

Answer 52

When the PO2 falls below 60mm Hg, they stimulate the respiratory centres to increase respiration rate; this is called hypoxic drive.