Respiratory anatomy

Question 1

What is the anatomy of the nasal cavity?

Answer 1

Nasal septum separates two halves, and largely made of cartilage, but lined by olfactory mucosa - very sensitive, with trigeminal nerve innervation. Olfactory bulb and tract present at top of cavity, with olfactory mucosa to allow sense of smell (olfactory nerves arise from the bulb).

Question 2

Describe the lining of the nasal cavities?

Answer 2

Have a triangular cross-section. Fairly smooth medial and inferior walls, but an elaborate lateral wall in which the respiratory epithelium covers three scroll-like plates of bones called the conchae.

Question 3

What is the purpose of the conchae?

Answer 3

Increase SA of nasal mucosa to condition air before reaching the lungs (bone protrusions covered in respiratory epithelium – inferior concha lower in cavity with middle concha near the top).

Question 4

What is the purpose of the nasal cavity? (x4 functions)

Answer 4

1. The inspired air passes through these warm, moist plates, becoming warmed and humidified on the way and so protecting the lower parts of the respiratory tract from cold shock and drying. 2. The nasal lining becomes cooled in inspiration. During expiration, the nasal lining cools the expired air. 3. To conserve water, during expiration, the nasal cavity retrieves water by condensation. 4. The nasal mucus and hairs help exclude a range of airborne particles.

Question 5

What is a consequence of the nasal cavity’s role of filtering air at conserving heat and water? Especially in exercise?

Answer 5

Narrow passages of the nasal cavity have a high resistance to airflow. This is particularly apparent through exercise, where the mouth is used instead for inspiration and expiration – hence, there is increased loss of water and exposure to airborne particles.

Question 6

What are the paranasal air sinuses?

Answer 6

A group of air-filled spaces around the nasal cavity. Found as pockets in the lateral walls of the nasal cavity.

Question 7

What is the function of the paranasal air sinuses? (x3 possible functions)

Answer 7

Unknown, but ideas include as ‘crumple zones’ in facial trauma, resonators for the voice and insulating sensitive structures such as dental roots and eyes from rapid temperature fluctuations in the nasal cavities.

Question 8

What is the anatomy of the paranasal air sinuses?

Answer 8

Frontal sinus present above the eyes (frontal bone). Sphenoid sinus found in sphenoid bone below pituitary gland. Ethmoid air cells (sinuses) are found high in nasal cavity on each side of the septum. Maxillae have opening to sinus above upper teeth – opening high inside maxillary sinus, so any infection/mucous cannot leave via the opening. And, of course, there are the three conchae.

Question 9

What is the anatomy of the pharynx – what three sections is it split into?

Answer 9

Nasopharynx (nasal cavity to end of soft plate). Oropharynx (soft plate to epiglottis). Laryngopharynx (epiglottis to opening of the airway).

Question 10

What is the soft plate?

Answer 10

The fleshy, flexible part towards the back of the roof of the mouth.

Question 11

How are the nasal cavities and pharynx kept open?

Answer 11

Not by cartilage like the rest of the respiratory anatomy, but by adjacent bones.

Question 12

What, out of the trachea and oesophagus, is the larynx and pharynx linked to respectively?

Answer 12

Larynx: trachea. Pharynx: oesophagus.

Question 13

What is the anatomical position of the larynx?

Answer 13

Above the thyroid glands.

Question 14

What are the cartilages of the larynx?

Answer 14

I don’t think I need to remember this in such detail – look at Sofia points after all. All cartilage hangs from the hypoid bone. Thyroid cartilage hangs from the hypoid bone, with inferior cricoid cartilage joined by cricothyroid ligaments. Epiglottis attached to hypoid bone.

Question 15

What do the vocal folds of the larynx look like during inspiration and phonation?

Answer 15

Look at photo. Remember other regional anatomy inc. Epiglottis. They vibrate to generate sound.

Question 16

What is the epiglottis?

Answer 16

A flap in the throat that keeps food from entering the trachea and lungs.

Question 17

What is phonation?

Answer 17

The process by which vocal chords produce sounds through vibration.

Question 18

What does a cross-section of the trachea look like?

Answer 18

Incomplete cartilage ring with opening where the oesophageal (and trachealis) muscle is – allows passage of food through the oesophagus.

Question 19

How is the tracheobronchial tree anatomy labelled?

Answer 19

Trachea divides at carina angle of Louis to right and left primary bronchi (outside the lungs). In the lungs, they branch to form lobular, secondary bronchi. Don’t worry about annular ligaments.

Question 20

How are the bronchi held open?

Answer 20

By cartilage horseshoes and plates.

Question 21

What are the two main areas of the chest?

Answer 21

Mediastinum and the lungs.

Question 22

What is the basic anatomy of the lungs?

Answer 22

[Refer to Anatomy topic in LSS].

Question 23

What is the top part of each lung called?

Answer 23

The apex – it projects 2-3cm above the clavicle in an adult and really lies in the root of the neck.

Question 24

What is the purpose of the pleural cavities of the lungs?

Answer 24

Each lung and the inside of the pleural cavities are covered by a thin, shiny, moist layer of tissue called the pleura, which allows each lung to slide smoothly within its pleural cavity during breathing.

Question 25

How do the pleural cavities induce breathing? !!!

Answer 25

Expansion of the pleural cavities produces a drop in the pleural pressure, so air flows through the airways into the lungs, which expand with the increase in pleural cavity volume. The lower part of each lung expands downwards to occupy much of the costadiaphragmatic recess (the lowest region of each pleural cavity, which in expiration contains no lung because the margin of the diaphragm is pressed closely against the lower part of the rib cage).

Question 26

What are the names of the fissures in the left and right lungs?

Answer 26

Look at photo.

Question 27

What is the anatomical position of the diaphragm?

Answer 27

Margin is attached to the costal margin (lower edge of the rib cage). Centre of dome bulges up because of pressure difference between pleural and abdominal cavities. Bulge is therefore higher in expiration.

Question 28

What are the motor nerves to the diaphragm?

Answer 28

Phrenic nerve (C3, 4, 5).

Question 29

What muscles produce breathing? (x4) What is the movement that each muscle induces, and what does this mean for the dimensions and sizes of the pleural cavities (for the two main muscles involved in breathing)?

Answer 29

Contraction of the diaphragm pulls the domed central tendon of the diaphragm down and so increases the height of the pleural cavities. Contraction of the intercostal muscles, which almost fill the spaces between adjoining ribs, pulls the ribs upwards towards the relatively fixed first rib, pulling them anteriorly also. So, inspiration increases the depth and width of the pleural cavities. The abdominal muscles and pelvic diaphragm are also involved in breathing!

Question 30

What are the alveoli?

Answer 30

Alveoli are microscopic spaces lined by very thin simple squamous epithelium through which oxygen and CO2 exchange take place with the blood in a network of alveolar capillaries surrounding them.

Question 31

Where do the alveoli capillaries come from?

Answer 31

These capillaries are on the pulmonary circuit, bringing deoxygenated blood from the right ventricle of the heart via the pulmonary trunk and pulmonary arteries.

Question 32

What are small airways defined as?

Answer 32

Airways with a diameter of less than 2mm. Describes bronchioles.

Question 33

What is a terminal airway?

Answer 33

Bronchioles.

Question 34

What airways are described as ‘large’ airways?

Answer 34

Bronchi.

Question 35

What is meant by the respiratory system has a double circulation?

Answer 35

LUNG HAS DOUBLE CIRCULATION – pulmonary and bronchial circulation. PULMONARY CIRCULATION: takes blood to the lungs where GASEOUS EXCHANGE occurs. BRONCHIAL CIRCUALTION: takes blood to the lung parenchyma to supply lungs with nutrients and remove waste. Most of the blood returns – like it would in the systemic circulation – to the right atria. However, there’s SOME drainage into the pulmonary veins, diluting the oxygen content in the left atria and ventricles.

Question 36

What are the cellular layers separating alveolar air from blood?

Answer 36

One cell thick alveolar epithelium. One cell thick capillary endothelium.

Question 37

How do alveoli resist collapse?

Answer 37

Achieved using surfactant and elastic tissue in the interstitium.