Lec 1- The Respiratory System

Question 1

What is the development of the Respiratory System?

Answer 1

It develops as a diverticulum (out pocket) from the pharynx.

It is from the primitive duct tube so it is endodermal in origin.

Question 2

What is the function of the Nasal Cavity?

Answer 2

1. induce turbulent flow (nasal conchae)
2. warm and moisten inspired air.
3. recover water from expired air
4. speech production (phonation)
5. Olfaction (sense of smell)

Question 3

What is the structure of the Nasal Cavity?

Answer 3

• It is folded and presents a large SA of contact between the air we breathe and the vascular mucosa that line the nasal cavity.
• The nasal cavities run horizontally and this is important for passing endoscopes into nasal cavity as need to know which way to pass the tube.

Question 4

What is the pathway of food?

Answer 4

Food goes down the oral cavity to the oesophagus.

Question 5

What is the pathway of air?

Answer 5

Air goes down the nasal cavity down the nasopharynx to the trachea.

Question 6

What are the three portions of the pharynx?

Answer 6

Nasopharynx
Oropharynx
laryngopharynx

Question 7

What three things does the pharynx connect to?

Answer 7

Nasal cavity, oral cavity and respiratory tract.

Question 8

What do the pharynx and larynx work together to do?

Answer 8

They work together to ensure that food and air enter the oesophagus and trachea respectively.

Question 9

What are the different paranasal sinuses?

Answer 9

sphenoidal sinus - before ear
ethmoidal cells - by side of eye
frontal sinus - by eyebrow
maxillary sinus - by the cheek

Question 10

What are the different components of the conducting airways?

Answer 10

1. trachea
2. primary (main) bronchi
3. Secondary (lobar) bronchi
4. Tertiary (segmental) bronchi
5. Bronchioles
6. Terminal Bronchioles

Question 11

Why do the trachea have horse shoe cartilage?

Answer 11

This is to keep the trachea open.

• this is because you do not want the negative pressure in the trachea to collapse when breathing in.
• there is no cartilage at the back because the oesophagus sits behind the trachea, so more room for the food bolus to bulge into as it makes its way down into the stomach.

Question 12

What make up the anterior and posterior wall of the thoracic cavity?

Answer 12

posterior - composed of vertebral bodies of the vertebral.

anterior - composed by sternum and costal cartilages.

Question 13

How does the ribs articulate with the vertebrae?

Answer 13

By the tubercle,
- the tubercle is a little lump that contains fact and that facet along with two facets on the head of the rib are where the ribs articulate with the vertebrae.

• the superior demifacet of one vertebrae and the inferior demifacet of the one above are where they articulate with the rib.
• one rib articulates with two vertebral bodies.

Question 14

What does the thoracic cavity contain?

Answer 14

Filled with heart and lungs.

Question 15

What is there mediastinum?

Answer 15

The mediastinum is a big structure in the midline that separates the two lungs.

Question 16

What are the two movements of the chest wall during breathing and describe them?

Answer 16

The bucket handle movement

• each rib is able to swing around this axis.
• —swing laterally and superiorly during inspiration.
• enables the chest to increase its lateral diameter.
• enables the volume of the chest to increase and pressure to decrease so air moves in.

The pump handle movement.
-each rib can swing superiorly, moving the sternum forward and increasing the diameter of the chest.

Question 17

What is the pressure needed for air to move into the lungs>?

Answer 17

Alveolar pressure must be lower than atmospheric pressure for air to move into the alveoli.
Negative pressure within the thorax causes air to move into the lungs.

Question 18

What is the innervation to the diaphragm?

Answer 18

Phrenic nerve

• made up from c3, c4 and c5
• these nerve roots keep the diaphragm alive.
• spinal cord injury affecting the neck may mean unable to breathe as may damage the phrenic nerve.

Vagus nerve
- this goes down and pierces the diaphragm which the oesophagus enters.

Question 19

What is the location of the phrenic nerve?

Answer 19

The phrenic nerve is at front - anterior

it runs anterior to the hilum of the lungs and sits at the front.

Question 20

What is the innervation of the Intercostal muscles?

Answer 20

it is supplied by major neurovascular bundle that runs beneath each rib.
It runs on the inferior edge of each rib.

Question 21

What are the different intercostal muscles?

Answer 21

Internal., external and inner most.

Question 22

What are the structures that pass through the diaphragm?

Answer 22

Vena Cava - T8 - 8 letters
Oesophagus - T10 - 10 letters
Aortic Hiatus - T12 - 12 letters

Question 23

Why do you crouch over and hold onto knees when out of breath?

Answer 23

This is because that position is fixing the pectoralis muscles, so the origin of the pectoralis becomes the humerus so it pulls on the thorax enabling us to get a bit more air into our lungs.

Question 24

Why do people with emphysema have neck in shoulder like posture?

Answer 24

This is because the SCM is working hard pulling the sternum and clavicle in aim to pull ribs up and give more ventilation.

Question 25

What does the use of accessory muscles to breathe indicate?

Answer 25

Respiratory distress.

Question 26

Describe the neurovasculature of the thorax.

Answer 26

• there is.a collateral bundle that runs at the bottom of the intercostal space.
• this bundle consists of intercostal vein, intercostal artery and intercostal nerve.
• the intercostal artery goes through the thoracic aorta.
• The intercostal nerve becomes smaller as it comes around as fibres are being distributed as changing from posterior to anterior.

Question 27

How does the blood drain from the intercostal system?

Answer 27

Via the Azygous system

Question 28

Why can you feel pain in the neck during an MI?

Answer 28

This is because the phrenic nerve is sensory so an MI can irritate the pericardium so you can feel irritation through the phrenic nerve.

Question 29

What is the Carina?

Answer 29

The carina is at the bifurcation of the trachea, so it is a very sensitive part.

Question 30

How many lobes does each lung have?

Answer 30

Right has 3
left has 2, this is because the heart is on left and the heart is indenting into the left lung, which means there is not enough space for the left lung so it has lost one of its lobes.

Question 31

Describe the positioning of the inferior lobes of each lung?

Answer 31

• they extend further round the back that it does at the front, which is why we listen to the lung at the back of the chest.

Question 32

Describe the angling of the bronchi?

Answer 32

The right bronchi is more angled than the left, so a foreign body inhaled by a child is more likely to go to the right lung than the left.

Question 33

What is the hilum?

Answer 33

It is where the nerves and vessels enter and leave the structure.

Question 34

Describe the positioning of the pulmonary artery.

Answer 34

The pulmonary artery sits superiorly to the veins and more anteriorly to the airways.

Question 35

Where do the lungs expand into when breathing?

Answer 35

• the lungs and pleura do not occupy the same space, when the lungs are inflated , they expand into the pleura.
• the lungs expand down into costodiaphragmatic recess, which is the space which the lungs will expand during inspiration.

Question 36

When can fluid accumulate in the costodiaphragmatic recess?

Answer 36

When there is pleural effusion.

Question 37

What is the function of the bronchial artery?

Answer 37

• to provide a second vascular supply to the lungs, which directly supply the lung tissue with oxygenated blood.
• they need to be preserved in lung transplants.
• they are important when there is a pulmonary embolus that blocks , as the bronchial artery is still able to supply oxygenated blood to tissue.

Question 38

Where is the dome of the diaphragm?

Answer 38

The right dome is around the fourth intercostal space.

The left dome is around the fifth intercostal space, as the left dome hits the apex of the heart.