1- histology

Question 1

what is respiratory epithelium?

Answer 1

pseudostratified columnar epithelial ciliated with goblet cells

Question 2

what are goblet cells?

Answer 2

unicellular glands, they secrete mucous and keeps surface moist (found in respiratory epithelium)

Question 3

what special cells are in root of nasal cavity?

Answer 3

specialised olfactory epithelium which is where get neuro-olfactory cells and get smell

Question 4

what is function of nasal cavity?

Answer 4

1. warming
2. moistening
3. filtering the inspired air

Question 5

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

Answer 5

called the vestibule = lined by keratinized stratified squamous epithelium

Question 6

what changes from the vestibule to deeper into nasal cavity?

Answer 6

vestibule = keratinised stratified squamous epithelium

deeper= loses keratin and changes epithelial cells to respiratory epithelium (pseudostratified ciliated columnar epithelial with goblet cells)

Question 7

what are seromucosal glands?

Answer 7

serous glands =produce liquid
mucous glands = produce sticky mucous

seromucosa glands = produce both

Question 8

what causes a blocked nose?

Answer 8

the lamina propria, a band of loose connective tissue containing seromucous glands (SM) and thin-walled venous sinuses (V) which can quickly engorge with blood and ‘block’ the nose.

Question 9

what is lamina propria?

Answer 9

a band of loose connective tissue containing seromucous glands & thin walled venous sinuses

*found under respiratory epithelium

Question 10

what lines the oral pharynx?

Answer 10

oral pharynx = middle part of pharynx that has both air and swallowed food

• this means it must resist abrasion so lined by non-keratnized stratified squamous epithelium

Question 11

what is general rule that i can use to try remember when keratanized or not?

Answer 11

keratonized = dry surfaces

non-keratonized = wet surfaces

Question 12

what lines the epiglottis?

Answer 12

lid bit of larynx (skeleton of cartilage)

the anterior part (sublingual part) of epiglottis touches tongue so lines by same as oral pharynx and is lined by non-keratinized stratified squamous epithelium
- this covers anterior surface over the apex and the upper part of posterior surface

Question 13

the larynx walls are made of cartilage and muscles & lined with respiratory epithelium - what is the exception to this?

Answer 13

the vocal cords that are covered with stratified squamous epithelium

Question 14

what composes the vocal cords?

Answer 14

true vocal cords = continuous with posterior surface of epiglottis so respiratory epithelium and seromucous glands

false cords = ventricles are spaces between the cords - bilateral and after that the cells change to non-keratinized stratified squamous epithelium

Question 15

what is trachea made up of?

Answer 15

15-20 C shaped cartilaginous rings, they’re deficient posteriorly (bits without cartilage) to allow expansion. These deficient bits have fibroelastic tissue & smooth muscle (trachealis muscle)

the rest of it has the normal respiratory epithelium then lamina propria (connective tissue & abundant elastic fibres) then submucosa of connective tissue with seromucous glands then cartilage then adventitia

Question 16

what type of cartilage is in trachea?

Answer 16

hyaline

Question 17

what are the different parts of the bronchi?

Answer 17

part outside lung = extra-pulmonary bronchi (structure similar to trachea)

part inside = intrapulmonary bronchi

Question 18

what are the 2 main changes between extrapulmonary bronchi and intrapulmonary bronchi?

Answer 18

extra to intra

1. smooth muscle = muscularis consisting of a ring of smooth muscle
2. cartilage = the rings are replaced by irregularly shaped cartilage plates

Question 19

what is the wall of bronchus made up of?

Answer 19

respiratory epithelium, lamina propria, muscularis consisting of smooth muscle & submucosa with adipose tissue and some seromucous glands

*also irregularly places cartilage plates

Question 20

when does bronchi turn to bronchiole?

Answer 20

bronchiole form when 1 mm

Question 21

what do bronchioles consist of?

Answer 21

• lack cartilage & glands but may contain a few goblet cells in initial bit

epithelium decreases in height from columnar to cuboidal as you progress down
- lamina propria composed of smooth muscle, elastic & collagenous fibres

Question 22

what is main difference between bronchi & bronchioles?

Answer 22

no cartilage

Question 23

what is the smallest bronchiole that before gas exchange?

Answer 23

terminal bronchioles

Question 24

what are the first part of bronchioles that have respiratory function?

Answer 24

respiratory bronchioles

Question 25

how do bronchioles play a role in asthma attacks and allergic reactions?

Answer 25

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

Question 26

what makes up the terminal bronchioles?

Answer 26

lined with cuboidal ciliated epithelium and contain non-ciliated club cells (previously called Clara cells) that project above the level of adjacent ciliated cells

Question 27

what are the roles of club cells?

Answer 27

• Stem cells
• Detoxification
• Immune modulation
• Surfactant production

Question 28

list the cells that alveoli are made up of

Answer 28

• type 1 alveolar cells
• type 2 alveolar cells
• alveolar macrophages

*alveolar cells also called pneumocytes

Question 29

when does gas exchange start?

Answer 29

in alveoli which are associated with respiratory bronchioles, alveolar ducts and alveolar sacs

Question 30

what are respiratory bronchioles lined with?

Answer 30

cuboidal epithelium

Question 31

what part of bronchial tree are responsible for spongy nature of lungs?

Answer 31

alveoli (about 300 million in each lung)

Question 32

what are type 1 alveolar cells?

Answer 32

simple squamous epithelium that lines alveolar surfaces (covering 90% of surfaces)

provide minimal thickness that is permeable to gases

Question 33

what are type 2 alveolar cells?

Answer 33

polygonal in shape, the free surface is covered by microvilli and the cytoplasm displays dense membrane bound lamellar bodies which contain surfactant.

The surfactant 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 34

where are alveolar macrophages found? and what is their function?

Answer 34

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 then 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 35

what is in septa of alveoli?

Answer 35

type 2 alveolar cells and macrophages - also permeated by capillary networks

Question 36

what does the air blood barrier consist of?

Answer 36

type 1 cells, the endothelial cell & basal lamina of each

Question 37

what is the visceral pleura?

Answer 37

= multi layered and immediately surrounding lungs & faces parietal pleura which lines thoracic cavity (pleural cavity between the 2)

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