Veterinary Histology: Respiratory System

Front 1

Principle Functions of the Respiratory System

Back 1

- air filtration
- air conduction
- gas exchange
- air passing over olfactory mucosa carries the stimuli for smell

Front 2

What is the respiratory tract derived from?

Back 2

- endoderm
- arises as a diverticulum of the foregut

Front 3

Conducting portion

Back 3

- nasal cavity
- naso and oropharynx
- larynx
- trachea
- primary bronchi

Front 4

Respiratory portion

Back 4

- secondary and tertiary bronchioles
- respiratory bronchioles
- alveolar ducts
- alveolar sacs
- alveoli

Front 5

Paranasal sinuses

Back 5

- communicate with the nasal cavity
- functions may be to reduce the weight of the skull
- lined with PSCC with interspersed goblet cells
- sinusitis is often a result of upper respiratory tract infection and usually involves all of the sinus caviities (canalso be caused by a a tooth root infection)

Front 6

Nasal cavity

Back 6

- warms and filters inspired air
- shape and increased surface area of the nasal turbinates results int eh removal of particles int the air through turbulent precipitation
- 3 regions: cutaneous, respiraotry, olfactory

Front 7

Turbulent precipitation

Back 7

- air stream is broekn into eddies which results in suspended matter in teh air being thrown against the mucus covered wall of the nasal cavity
- the rich blood supply of the lamina propria resutls in warming the air before it gets to the lower airways

Front 8

Nasal cavity: cutaneous segment

Back 8

- most rostral
- lined by keratinized, stratified squamous epithelium

Front 9

Nasal cavity: respiratory segment

Back 9

- largest part of nasal cavity
- underlying lamina propria is attached to the periosteum of teh turbinate bones
- lateral wall has shelf-like, boney projections called turbinates or conchae
- 5 types of cells: PSCC, goblet, brush, small granule, basal

Front 10

Brush cells

Back 10

- cell with short blunt microvilli
- function is uncertain.. receptor??

Front 11

Small granule cells

Back 11

- enteroendocrine cells
- secretory products from tehse cells suggest that there is a role in vascular perfusion of the region

Front 12

Nasal cavity: Olfactory segment

Back 12

- found in caudal dorsal region of nasal cavity
- 3 types of cells: olfactory, supporting and basal

Front 13

Olfactory cells

Back 13

- bipolar neurons
- numerous apical cilia that contain odorant-binding proteins and thus act as olfactory receptors
- basal pole of teh cells give rise to an axonal rpocess that leaves and makes the olfactory nerve
-

Front 14

Supporting cells

Back 14

- most numerous cell type
- have lots of lipofuscin as a result of oxidation of lipids in teh cell

Front 15

Olfactory glands

Back 15

- found in submucosa
- ducts pass through the epithelial layer
- provide a watery secretion which washes the mucosal surface of odorants and clears it for new ones
- they also have lipofuscin and cytochrome P-450-monooxygenase
- cells of the olfactory glands are though to be th eprimary site for chemically induced nasal tumors

Front 16

Larynx

Back 16

- epithelium is nonkeratinized stratified squamous epithelium
- some lymphocytes, plasma cells and mast cells are seen
-

Front 17

Tracheobronchial airways

Back 17

- caudal to the larynx
- PSCC epithelium, goblet cells and basal cells

Front 18

Trachea

Back 18

- supported by C-shaped hyaline cartilage rings with fibroelastic tissue and the trachealis muscle completing the ring
- birds have a full ring of cartilage

Front 19

Bronchi vs Bronchioles

Back 19

- bronchioles have no cartilage or goblet cells and glands (but the bronchi do)

Front 20

Bronchial glands

Back 20

- present in larger bronchi
- serous cells