Respiratory system

Question 1

The entrance to the respiratory system is through the …………….

Answer 1

external nares

Question 2

The nasal chambers are divided into left and right by ………………………

Answer 2

a cartilaginous septum

Question 3

The nasal turbinates are found within the nasal chambers. Describe the structure of the nasal turbinates.

Answer 3

Fine scrolls of bone
Covered by a ciliated mucous membrane with excellent blood supply

Question 4

Which “anatomical direction” would you use to correctly describe the position of the nares on the head?

Answer 4

Rostral

Question 5

What is a sinus?

Answer 5

Air-filled cavity within a bone

Question 6

Describe the function of the paranasal sinuses.

Answer 6

Lighten the weight of the skull

Surfaces for heat exchange + mucus secretion.

Question 7

The pharynx is the anatomical name for the throat area. It is divided into two areas. Name these two areas.

Answer 7

The naso-pharynx and the oro-pharynx

Question 8

What is the function of the nasal turbinates?

Answer 8

Warm and moisten the air that is breathed in.
The ciliated mucous membrane helps to trap particles and waft them to the pharynx where they are swallowed (rather than enter the airways).

Question 9

What structure separates the dorsal part of the pharynx from the ventral portion?

Answer 9

The soft palate

Question 10

What structure separates the nasal cavity from the oral cavity?

Answer 10

The hard palate

Question 11

What is the function of the Eustachian (auditory) tubes which connect the pharynx to the middle ear?

Answer 11

To equalise pressure on either side of the ear drum / tympanic membrane.

Question 12

In terms of swallowing, what is the function of the soft palate?

Answer 12

The soft palate prevents food from entering the nasal passages during swallowing.

Question 13

Describe the location of the larynx

Answer 13

The larynx is caudal to the pharynx, in midline and ventral in the neck

Question 14

Describe three functions of the larynx

Answer 14

Air flow into respiratory tract

Stop anything but gases from entering the respiratory system

Vocalisation

Question 15

Describe the structure and function of the epiglottis

Answer 15

The epiglottis is a flap of elastic cartilage.

Seals-off the entrance to the larynx when an animal swallows.

Question 16

Describe the purpose of the incomplete rings of cartilage found in the walls of the trachea

Answer 16

Keep the trachea open (prevent it from collapsing).

The rings are incomplete on their dorsal surface which allows the oesophagus to ‘borrow space’ from the trachea during swallowing.

Question 17

Describe the lining of the trachea

Answer 17

Ciliated mucous epithelium
- Mucus helps trap particles
- Cilia pushes the mucus up to the pharynx where it is swallowed

The tracheal lining is also sensitive and if stimulated, a cough reflex will aid in expelling foreign material.

Question 18

How does the support of the bronchi differ from that of the support of the trachea?

Answer 18

Complete cartilaginous rings: no need to make way for expansion of the oesophagus.

Question 19

Following the bronchial tree to the point where the cartilaginous support disappears, the bronchi become …………….

Answer 19

bronchioles

Question 20

The smallest diameter branches of the bronchial tree are known as ……………….. which lead directly to the ………………

Answer 20

alveolar ducts
alveoli

Question 21

Describe the structure of an alveolar sac.

Answer 21

Has a number of alveoli = thin-walled sacs surrounded by capillary networks.

Question 22

What is meant by the term ‘pulmonary membrane’.

Answer 22

Epithelial lining of the alveolus.

Question 23

Describe the process of gas exchange across the pulmonary membrane.
(Note that you can’t talk about gas exchange if you only mention one gas!)

Answer 23

Oxygen diffuses across the pulmonary membrane from the alveolar space to the capillaries in the pulmonary circulation
Carbon dioxide in the blood is excreted into the alveolus.

Question 24

What is meant by the term ‘dead space’?

Answer 24

All parts of the respiratory tract which are not involved with gas exchange – i.e. everything except the alveoli.
They conduct air into and out of the alveoli.

Question 25

Describe the location of the lungs.

Answer 25

The right and left lungs in thoracic cavity either side of the mediastinum. They fill the thorax except for the mediastinal space in mid-line.

Question 26

The lungs are lined on the external surface by a membrane called ...............

Answer 26

the pleura

Question 27

Describe the purpose of the pleura.

Answer 27

Secrete pleural fluid: reduces friction as the lungs move during respiration.

Question 28

The space between the lungs is known as the mediastinum. List four structures found within the mediastinum.

Answer 28

Heart Blood Vessels Oesophagus Trachea.

Question 29

The diaphragm is a sheet made from .............. and it has a nerve supply from the ................... nerve.

Answer 29

muscle phrenic

Question 30

The lungs fill the ......(a)........... cavity except for the area in midline containing the heart and major vessels. The lungs are surrounded by the ...........(b)............ membranes. Caudally in the thoracic cavity is the .............(c).............; this separates the thoracic cavity from the ............(d)............... cavity.

Answer 30

a. thoracic b. pleural c. diaphragm d. abdominal

Question 31

When the diaphragm contracts, it ...........(e)............., which ...............(f)................. the amount of space in the thoracic cavity. The resulting ...........(g)............... pressure causes ..............(h)................................

Answer 31

e. flattens f. increases g. negative h. air to move into the lungs

Question 32

The external intercostal muscles cause the ribs to move ................(i)....................... which also ...............(j).................. the space in the thoracic cavity and .................(k)..................... The internal intercostal muscles cause air to move .............(l) ................. the lungs during ...............(m)...............

Answer 32

i. upwards and outwards j. increases k. fills the lungs with air l. out of m. forced expiration

Question 33

Breathing is controlled by the respiratory centres which fall within which areas of the brain?

Answer 33

The Pons and the Medulla

Question 34

There are chemoreceptors within the body which measure chemicals within the blood to control respiration. Where are the main two groups of peripheral chemoreceptor and by what names are the known?

Answer 34

The aorta – the aortic glomi The carotid arteries – the carotid glomi

Question 35

Where are the main central chemoreceptors for respiratory control?

Answer 35

The medulla detects mainly CO2 levels

Question 36

Which other substances are detected by the body’s respiratory chemoreceptors?

Answer 36

pH (acidity) and oxygen levels

Question 37

What effect will an increase in CO2 levels have on the respiratory rate?

Answer 37

Respiratory rate will increase to remove the excess CO2

Question 38

What effect will a decreased blood pH (a rise in acidity) have on the respiratory rate?

Answer 38

Respiratory rate will increase to remove the excess acidity (which is generally caused by high CO2 levels)