7. Respiratory System

Question 1

What is respiratory epithelium?

Answer 1

Simple/ pseudo stratified columnar ciliated with goblet cells interspaced

Question 2

Describe the functions of the nose

Answer 2

Filter - Covered by respiratory epithelium
Humidify - Thin walled blood vessels warm inspired air
Olfactory
- Three bony projections
- Nasal sinuses of air lowers weight of skull

Question 3

Describe olfactory epithelium

Answer 3

Columnar pseudostratified with absence of goblet cells. Embedded myelinated olfactory nerves and blue staining glands secrete solvent for odorous substances = detects odours

Question 4

Describe the larynx

Answer 4

Respiratory epithelium overlies loose irregular fibrous tissue and held open by hyaline cartilage.

Question 5

Describe the vocal chords

Answer 5

Reinke’s Space (no lymphatics) tensioned by vocalist (skeletal) muscle fibres.

Question 6

Describe the trachea

Answer 6

Lined by respiratory epithelium and held open by c-shaped hyaline cartilage rings (joined by smooth trachealis muscle). Numerous seromunicious glands and lymph nodes

Question 7

Describe Bronchi

Answer 7

Respiratory epithelium lines a band of smooth muscle and held open by hyaline cartilage. MALT lymph nodules and pulmonary vessels lie in connective tissue.

Question 8

Describe bronchioles

Answer 8

Simple columnar ciliated epithelium but goblet cells replaced by Clara cells (unknown function). No hyaline cartilage but prominent band of smooth muscle and lymph nodes + pulmonary vessels present.

Question 9

Terminal -> Respiratory Bronchioles

Answer 9

A prominent sphincter like ring of smooth muscle regulates ventilation to alveoli and lined by sparsely ciliated simple cuboidal epithelium with Clara cells.

Question 10

Describe alveoli

Answer 10

Each 250um in diameter lined by simple squamous epithelium of two types. Embedded fibroblasts produce reticulin and elastic tissue for recoil. Pores of kohn ensure equal inflation but spreads infection.

Question 11

Describe Type I pneumocytes

Answer 11

Form thin air-blood barrier (200-800nm) with flattened squamous separated by a basement membrane.

Question 12

Describe Globular Type II Pneumocytes

Answer 12

Synthesises and secretes lipid-rich surfactant to lower surface tension of air sacs and prevent dedication.

Question 13

What supplies the lungs with O2?

Answer 13

Bronchial Arteries

Question 14

Name the 5 layers of the visceral pleura

Answer 14

Pleural Cavity
1. Flattened squamous mesothelial cells
2. Loose fibrocollagenous connective tissue
3. Irregular external elastic
layer
4. Interstitial fibrocollagenous layer
Irregular internal elastic layer