Histology

Question 1

f: 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 (smelling)
Lungs function in blood pressure control via renin-angiotensin system

Question 2

describe the path of inhaled air

Answer 2

. Air enters the nose or mouth travels via the pharynx and larynx into the trachea which branches into the principal bronchi to convey the air to the lungs. In the lung each bronchus divides into smaller bronchi which divide into smaller bronchioles. These bronchioles terminate in the alveolar sacs where gaseous exchange occurs

Question 3

f: nasal cavity

Answer 3

Warming
2. Moistening
3. Filtering
the inspired air.

In addition in the roof it contains an area of specialised olfactory epithelium.

Question 4

what is the initial part of the nasal cavity called and lined by?

Answer 4

vestibule

keratinised stratified squamous epithelium

Question 5

name the components of the respiratory epithelium

Answer 5

Pseudostratified columnar epithelium ciliated with goblet cells

Question 6

what is under the respiratory epithelium (RE) ?

Answer 6

lamina Propria

Question 7

what is the lamina propria composed of?

Answer 7

loose connective tissue
seromucous glands
thin-walled venous tissues

Question 8

How do sinuses block the nose?

Answer 8

thin-walled venous sinuses (V) which can quickly engorge with blood and ‘block’ the nose.

Question 9

why is the oropharynx lined by non-keratinized stratifies squamous epithelium?

Answer 9

the oropharynx transmits both air and swallowed food, it must resist abrasion

Question 10

what are the walls of the larynx made up of and what is the exception?

Answer 10

made up of cartilage and muscles with respiratory epithelium lining its surfaces with the exception of the vocal folds

Question 11

what are the vocal folds covered with?

Answer 11

stratified squamous epithelium

Question 12

how many cartilages does the trachea have on avg?

Answer 12

15-20

Question 13

what muscle is the open side of the cartilage spanned by?

Answer 13

fibroelastic tissue and smooth muscle (trachealis muscle).

Question 14

what shape is the cartilage?

Answer 14

c shaped

Question 15

name the layers and the components of the trachea wall

Answer 15

The wall of the trachea includes a 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 16

at what size of the bronchus is the cartilage lost? what is this airway called?

Answer 16

when the airway is 1mm in diameter

bronchioles

Question 17

what does the epithelium change to as you move from the bronchus to the bronchioles?

Answer 17

from columnar to cuboidal

Question 18

d:terminal bronchioles

Answer 18

The smallest bronchioles that lack respiratory (gas exchange) function

Question 19

what type of stimulation does the SM in the bronchioles respond to?

Answer 19

respond to parasympathetic innervation, histamine and other factors by contracting and constricting the diameter of the bronchiole

Question 20

what lines the terminal bronchioles?

Answer 20

cuboidal ciliated epithelium and contain non-ciliated club cells

Question 21

f: club cells

Answer 21

Stem cells
Detoxification
Immune modulation
Surfactant production

Question 22

what is the low cuboidal epithelium replaced by when it moves to alveoli?

Answer 22

replaced by discontinuous squamous type I alveolar cells.

Question 23

where does gas exchange occur?

Answer 23

in the alveoli

respiratory bronchioles

Question 24

what do alveoli look like?

Answer 24

resemble thin-walled pockets similar to a honeycomb

Question 25

d: pneumocytes

Answer 25

alveolar cells

Question 26

what does alveolar epithelium consist of?

Answer 26

Type I alveolar cells and Type II alveolar cells

Question 27

how much of the alveolar surface is covered by type 1 alveoli?

Answer 27

90%

Question 28

what is the composition of alveoli type 1 cells?

Answer 28

simple squamous epithelium

Question 29

what does the type 1 alveolar cells allow?

Answer 29

provide a barrier of minimal thickness that is permeable to gases
gas exchange

Question 30

what shape are type 2 alveolar cells?

Answer 30

polygonal in shape

Question 31

describe the structure of the type 2 alveolar cells

Answer 31

the free surface is covered by microvilli and the cytoplasm displays dense membrane bound lamellar bodies which contain surfactant

Question 32

how is the surfactant released?

Answer 32

exocytosis

Question 33

f: surfactant

Answer 33

is released by exocytosis and spreads over the pulmonary surface to reduce the surface tension at the air-fluid interface

Question 34

what does the surfactant reduced the chance of happening?

Answer 34

alveolar collapse at the end of expiration

Question 35

apart from type 1 + 2 alveolar cells, what other cell is present in the alveoli?

Answer 35

alveolar macrophages - dust cells

Question 36

what happens to the dust cells and how do they arise?

Answer 36

free cells either in the septa or migrating over the luminal surfaces of the alveoli, phagocytosing inhaled particles that may have escaped entrapment by the mucous lining of the airway. They typically will migrate up the bronchial tree, transported by ciliary action, to the pharynx where they are swallowed or will move into the septal connective tissue where they will remain

Question 37

what is the thin tissue at the septa of the alveoli referred to as?

Answer 37

air-blood barrier

Question 38

what does the air-blood barrier consist of?

Answer 38

consists of the Type I cell, the endothelial cell and the basal lamina of each

Question 39

what does the visceral pleura consist of?

Answer 39

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