Histology of nasal cavities etc.

Question 1

Nasal cavity

Answer 1

Hyaline cartilage
Bone
Skin (keratinocytes and connective tissue)
Sebaceous glands
Vibrissae
Mucosa
- Epithelial layer with basement membrane and lamina propria
-- Warms air, highly vascularized 
--Keeps epithelium from drying out

Air enters through the nares into the nasal vestibules. The inferior 2/3rd of nasal cavities = respiratory region.

The stratified, squamous epithelium of the mucosa in the anterior cavity becomes ciliated, columnar and pseudostratified in the posterior cavity

Question 2

3 distinct part of mucosa

Answer 2

epithelial part
basement membrane
lamina propria

Question 3

bony structures in the nose

Answer 3

3 conchae (or turbinates)

have a whole capillary system shaped in order to release heat into the incoming cold air by increasing the surface area of the nose.

Question 4

2 types of histology in this region

Answer 4

stratified squamous epithelium or respiratory ciliated, columnar and pseudostratified epithelium

Question 5

respiratory epithelium

Answer 5

is found in the nasal cavities, pharynx and larynx

Pseudostratified, columnar, ciliated epithelial cells
Goblet cells
Basal cells
Brush cells- may be like stem cells
Small granule (Kulshitsky) cells- part of the diffuse neuroendocrine system (DNES)

Question 6

functions of mucus

Answer 6

keep epithelium hydrated, trap germs and particles

Question 7

smelling

Answer 7

tiny molecules of the substance come in, bind to G protein coupled receptors, axons travel through cribriform plate. THen into the olfactory bulb (this is when it becomes a cranial nerve)

Question 8

what happens when you break your cribriform plate?

Answer 8

lose CSF! Clear watery fluid coming out of the nose. If it comes rushing out upon standing up that is likely CSF.

Question 9

olfactory region histology

Answer 9

Olfactory region in dome of each nasal cavity, lined with olfactory mucosa
- Olfactory epithelium:
— Olfactory receptor cells/Olfactory neurons (bipolar neurons)
— Sustentacular cells (parallel to glia) also known as OLFACTORY ENSHEATHING GLIA
— Basal cells (parallel to stem cells)
— Brush cells (same as in respiratory epithelium)
Lamina Propria is contiguous with periosteum of underlying bone

Olfactory Glands (Bowman’s glands- gives the boogers their particular characteristics)

• • Lipofuscin + serous secretions give nasal mucous its brown-yellow color
• • Secretions both traps molecules and dissolves odorants

Question 10

A special aspect of sustentacular cells is that they are

Answer 10

permissive to stem cells becoming new neurons

Question 11

Olfactory mucosa designed to trap volatile odorants

Answer 11

Olfactory Neurons (ON) are bipolar neurons present throughout the epithelium

• • Apical pole has non-motile cilia
• • Large, unmyelinated axons leave epithelium and unite in lamina propria as small nerves.
• ——Pass through small foramina in cribiform plate, come together and become the olfactory nerve (CN I)

Sustentacular cells: columnar, broad apex, microvilli. Most numerous in epithelium.
Basal cells: small, spherical/cone shaped, replace olfactory neurons every 2-3 months
Brush cells (not seen): columnar, microvilli, basal surface comes into contact with CN V

Question 12

Paranasal sinuses are extensions of the respiratory epithelium of the nasal cavity

Answer 12

Bilateral cavities in the frontal, maxillary, ethmoid and sphenoid bones (named accordingly)

Lined with thinner respiratory epithelium (pseudostratified, columnar), fewer goblet cells

Question 13

Pharynx contains 3 regions, each has its own histological characteristics

Answer 13

Nasopharynx

• • Adenoids
• • Orifice of eustachian tubes

Oropharynx

• • Soft palate
• • Base of tonuge
• • Tonsils
• • Uvula

Hypopharynx

Question 14

Nasopharynx epithelia

Answer 14

has 2 basic types of epithelia: stratified squamous (scattered a bit throughout) and respiratory (mostly respiratory)

There is also a lot of “transitional” epithelium throughout the pharynx

Question 15

lymphoepithelium

Answer 15

Nasopharynx has “lymphoepithelium”

Epithelium is interrupted by small lymphocytes

Nasopharyngeal tonsils (adenoids) have extranodal lymphoid tissue, has germinal centers (MALT)

Question 16

Oropharynx histological properties

Answer 16

Stratified, squamous epithelium, not respiratory, nor transitional (similar to oral cavity)

The tonsils in the oropharynx have “crypts” from invagination of mucosa

Question 17

Larynx

Answer 17

Larynx is passageway between pharynx and trachea. Respiratory Conduit and Produces Sound

Includes epiglottis, supraglottis, glottis, subglottis

Question 18

Epiglottis

Answer 18

cartilage flap, prevents swallowed food or fluid from entering that passage

food will go down the hypopharynx into the esophagus

Question 19

Supraglottis:

Answer 19

Area above the vocal cords (vocal folds), includes the false vocal cords (vestibular folds)

Question 20

Glottis:

Answer 20

Includes the true vocal cords. Vocalis muscle attaches

Question 21

Subglottis

Answer 21

Area below vocal cords. Extends to cricoid cartilage.

Question 22

Larynx contains

Answer 22

characteristic tissues in different compartments: specialized for sound or respiration

= Epiglottis covered by stratified squamous epithelium
- Glottis: Vocal folds covered by stratified squamous epithelium

• Supraglottis
  surrounded by seromucous glands
  Vestibular folds contain MALT. Covered by respiratory epithelium
• Subglottis covered by respiratory epithelium

Question 23

in the larynx, respiratory epithelium is going to be where?

Answer 23

supraglottis or subglottis

Question 24

in the larynx, stratified squamous epithelium is going to be wherle?

Answer 24

epiglottis or glottis

Question 25

Skeleton of the larynx composed of

Answer 25

cartilage and connective tissue Epiglottis and corniculate cartilage are elastic Thyroid, cricoid, and arytenoid are hyaline Can calcify or ossify with age