Respiratory system Flashcards
What are the different ways to classify a glandular epithelia?
- According to cell number → Unicellular (Goblet cells) vs Mutlicellular (sweat glands)
- Fate of secretion → Exocrine (salivary glands) vs Endocrine (endocrine pancreas)
- Way the secretory product leaves the cell → Merocrine (sweat gland) vs Holocrine (sebaceous gland) vs Apcorine (mammary gland)
- Ducts → Simple (gastric gland) vs Compound (salivary gland)
- Secretory protion → Tubular (sweat gland) vs Acinar {Mucous (sublingual) vs Serous (parotid)}
What is the difference between an exocrine and and endocrine gland?
Endocrine:
- Releases secretory product through a duct on a surface
Exocrine:
- No duct
- Production of hormone released direclty to the blood stream → act far from site of secretion
- In maturation, the duct disappears → mass of cell detached from epithelium → capillaries
2 types of endocrine glands….
What are the 4 possibilities for glandular classifications based on the secretory portion?
*For simple ducts
- Simple tubular (Gastric gland)
- Simple coiled tubuler (sweat gland)
- Simple branched tubular (Pyloric glands)
- Simple branched acinar (trachea)
*acinus = 1, acini = more than 1
What are the different possibilities of glandular classifications based on secretory portion?
*For compound ducts
- Compound Tubule-Acinar (Submandibular gland)
- Compound Tubular
- Compound Acinar (Parotid/Sublingual glands)
What are the 2 portions of the respiratory system?
Conducting portion:
Nasal cavity → Nasopharynx → Oropharynx → Larynx → Trachea → Bronchi → Bonchioles (regular and terminal bronchioles)
Respiratory portion:
Respiratory bronchioles → Alveolar ducts → Alveolar sacs → Lung alveoli
What are the fuctions of the conducting and respiratory portions of the respiratory system?
Conducting portion: warming, humidifying, cleaning, and delivery of air
*Structure to ensure uninterropted supply of air (cartilage, smooth muscles, CT → provide rigidity, flexibility and extensibility)
*Possess glands and ciliated cells to remove foreign particles
Respiratory portion: site for gas exchange (O2, CO2)
What are the general components of the conducting portion of the trachea? (layers)
Lumen → Outside:
Lumen → Epithelium (Mucosa) → Lamina propria (Mucosa) → Submucosa (contains glands) → smooth muscles + Hyalin cartilage → Adventitia (dense irregular CT)
How is the Epithelium of the mucosa classified?
How is the Lamina propria classified?
Pseudo stratified columnar ciliated epithelium with goblet cells
Lamina Propria = Loose C.T., contains elastic fibers, capillaries
What structures are considered to be in the submucosa?
- Denser C.T.
- Glands (serous and mucous acini)
- A bit of Trachealis muscle (smooth muscles)
How is the CT of the adventitia classified?
Dense irregular C.T.
What are the features of the serous acinus and the mucous acinus in the submucosa?
Serous Acinus:
- Pyramidal cells
- Small lumen
- Acidophilic granules (which are?)
- Myoepithelial cells
- BM
- Aqueous secretions to humidify the air and facilitate breathing
Mucous Acinus:
- Columnar cells w/ ground/basal nucleus
- Secretes mucus to stick to foreign particles
- Pale cytoplasm (doesn’t stain well with eosin)
- No myoepithelial cells
**FINISH AND CONFIRM
What are the different cells found on the BM of the pseudo stratified columnar ciliated epithelium of the mucosa?
- Goblet cells → columnar, triangular nucleus, secrete mucous, Unicellular glands
- Ciliated cells → Columnar, most abundant, 100s of cilia (up to 5um long)
- Brushy cells (sensory cells?) → not seen in light microscope, CD8 precursors
- Small Granule cells → granules stained with Argentaffin, granules contain serotonin (permeabilty of capillaries), norepinephrine (smooth muscle constriction)
- Short cells → stem cells giving rise to the other types
How does the mucosa epithelium change in smoking individuals?
Smoking causes Squamous Metaplasia
Short cells stop producing a pseudo stratified epithelium → produce squamous, dry epithelium
What sections will cilia never be found in?
Longitudinal section
What is the general structure of a cilia?
- Basal body at the base
- Axoneme is the “continuation” of the basal body
- Axoneme is covered by a plasma membrane