Respiratory system

Question 1

What type of epithelium lines lower respiratory tract? where is it located?

Answer 1

-Trachea
-lined by ciliated pseudostratified columnar epithelium

Question 2

Denote what epithelial cells types are found in lower repspiratory tract?

Answer 2

mainly mucus-secreting cells, ciliated cells & stem cells

Question 3

Describe how specialised cells aid in struc/func of bronchial tree

Answer 3

-as bronchial tree narrows from bronchi to bronchioles
-fewer ciliated and goblet cells, more Club cells
-reduced mucus production and cilia
-focuses on maintaining open airways, minimising resistance, and preparing air for efficient gas exchange in alveoli.

Question 4

Define alveolus. How many are there?

Answer 4

-tiny air sacs that function as basic respiratory units
-150 million alveoli in each lung

Question 5

What are the alveolus cell types?

Answer 5

Type 1 alveolar cells (squamous)
and 2 alveolar cells (round to cuboidal)

Question 6

Describe type 1 alveolar cells

Answer 6

-squamous
-allow for rapid gas diffusion bwn alveolus & bloodstream
-cover 95% of alveolus SA

Question 7

Describe type 2 alveolar cells

Answer 7

-round to cuboidal cells
-cover 5% of alveolar surface
-repair alveolar epithelium when squamous (Type I) cells are damaged
-secrete pulmonary surfactant that coat alveoli & prevent from collapsing during exhalation

Question 8

Describe steps of conduction system

Answer 8

1. Sinuatrial (SA) node fires
2. Excitation spreads through atrial myocardium
3. AV node fires
4. Excitation spreads down the AV bundle
5. Subendocardial branches distribute excitation through ventricular myocardium