Histology

Question 1

What is the functions of the respiratory system?

Answer 1

Supplies oxygen to the blood for delivery to cells throughout the body
Removes carbon dioxide that has been accumulated in the blood from the tissues of the body
Phonation
Olfaction
Lungs function in blood pressure control via renin-angiotensin system

Question 2

What does the nasal cavity provide an extensive area for?

Answer 2

Warming
Moistening
Filtering inspired air
The roof contains an area of specialised oflacory epithelium

Question 3

What is the vestibule of the nasal cavity lined by?

Answer 3

Keratinised stratified squamous epithelium

Question 4

What does the lining change to when you get deeper into the nasal cavity?

Answer 4

The keratin is lost and is changed to pseudostratified ciliated columnar epithelium with goblet cells - more commonly known as respiratory epithelium

Question 5

What is present in respiratory epithelium?

Answer 5

Pseudostratified columnar epithelium ciliated with goblet cells - respiratory epithelium 
Goblet cell 
Basal cell (stem cell) 
Cilia 
Lamina propria/submucosa

Question 6

What is under the respiratory epithelium (RE)?

Answer 6

Lamina propria, a band of tissue containing seromucous glands ( M and S) and a rich venous pleuxs (V) which can quickly engorge with blood and block the nose

Question 7

What is the oropharynx lined with and why?

Answer 7

Non-keratinized stratified squamous epithelium, as is the anterior (lingual) surface and upper part of the posterior surface of the epiglottis. The oropharynx transmits both air and swallowed food as it must resist abrasion

Question 8

What is the larynx made up of?

Answer 8

Cartilage and muscles with respiratory epithelium lining its surfaces with the exception of the vocal folds and adjacent structures, which are covered with stratified squamous epithelium

Question 9

Where is the trachea located?

Answer 9

Continuous with the larynx and terminates by dividing into the main bronchi

Question 10

How many cartilages does the trachea contain and what is their shape?

Answer 10

15-20 C shaped cartilages. The open side of the C of the cartilage is spanned by fibroelastic tissue and smooth muscle (trachealis muscle)

Question 11

What type of cells lines the trachea?

Answer 11

Lining of respiratory epithelium backed by a basal lamina, a lamina propria of connective tissue with abundant elastic fibres and a submucosa of connective tissue that includes numerous seromucous glands

Question 12

What does the trachea divide into?

Answer 12

2 main (primary) bronchi which divide further within the lungs.

Question 13

What are the rings of cartilage replaced by in the bronchus?

Answer 13

Irregulary shaped cartilage plates

Question 14

What type of cells make up the bronchus?

Answer 14

Respiratory epithelium (RE), lamina propria (LP), a muscularis consisting of a ring of smooth muscle and a submucosa (SM) with adipose tissue and some seromucous glands

Question 15

What happens to the size of the bronchi as they branch?

Answer 15

They become smaller and the cartilage becomes more discontinuous and is finally lost when the airway is about 1mm in diameter

Question 16

What is the name of the smaller airways that lack cartilage?

Answer 16

Bronchioles

Question 17

What is the structure of bronchioles?

Answer 17

They are less than 1mm in diameter and lack cartilage and glands but may containt a few goblet cells in their initial portion

Question 18

What happens to the epithelium as you move down the resp tree?

Answer 18

It decreases in height from columnar to cuboidal as you progress down the tree to the smallest bronchioles. The lamina propria is composed of smooth muscle and elastic and collagenous fibres

Question 19

What is the names of the different types of bronchioles?

Answer 19

The smallest ones that lack respiratory function are called terminal bronchioles which then branch into the respiratory bronchioles which can perform gas exchange

Question 20

What does the smooth muscle of the bronchioles respond to?

Answer 20

Parasympathetic innervation, histamine and other factors by contracting and constricting the diameter of the bronchiole. This mechanism plays a significant role in asthma attacks and allergic reactions

Question 21

What are terminal bronchioles lined by?

Answer 21

Cuboidal ciliated epithelium and contain non-ciliated club cells that project about the level of adjacent ciliated cells

Question 22

What is the function of club cells?

Answer 22

Stem cells
Detoxification
Immune modulation
Surfactant production

Question 23

What interrupts the continuity of the respiratory bronchioles?

Answer 23

Alveoli

The low cuboidal epithelium is replaced by discontinous squamous type 1 alveolar cells

Question 24

Where does gas exchange occur in the lungs?

Answer 24

Alveoli which are found associated with respiraotry bronchioles, alveolar ducts and alveolar sacs

Question 25

What is the structure of alveoli?

Answer 25

The terminal portion of the bronchial tree that is responsible for the spongy nature of the lungs. They resemble thin-walled pockets.

Question 26

What occurs in alveoli?

Answer 26

Oxygen and CO2 exchange

Question 27

What are the two types of alveoli and what are their functions?

Answer 27

Type 1 and Type 2
Type 1 = simple squamous epithelium that lines the alveolar surfaces covering over 90% of the alveolar surface. Provide a barrier of minimal thickness that is permeable to gases
Type 2 = polygonal shape, free surface is covered by microvilli and the cytoplasm has membrane bound lamellar bodies which contain surfactant

Question 28

How is surfactant spread over the lungs?

Answer 28

It is released by exocytosis and spreads over the pulmonary surface to reduce the surface tension at the air-fluid interface. This reduces the tendency for the alveoli to collapse at the end of expiration

Question 29

What type of WBC are present in the alveoli and what do they do?

Answer 29

Alveolar macrophages that phagocytose inhaled particles that have escaped entrapment by the mucous lining of the airways. They will migrate up the bronchial tree by ciliary action to the pharynx where they are swallowed or move into septal connective tissue

Question 30

What is the visceral pleura made up of?

Answer 30

Outer layer of simple squamous epithelium called mesothelium backed by layers of fibrous and elastic connective tissue

Question 31

What is the the difference between visceral and parietal pleura?

Answer 31

Visceral pleura surrounds the lung whereas parietal pleura is of a similar makeup but simpler and lines the thoracic cavity

Question 32

What is between the visceral and parietal pleura?

Answer 32

Small amount of lubricating fluid