Respiratory Histo Flashcards
_____ portion includes air passages that lead to site of respiration in the lungs
Conducting portion
_____ portion is the locations where gas exchange occurs
Respiratory portion
What things are involved in the respiratory portion?
Respiratory bronchioles
Alveolar ducts
Alveolar sacs
Alveoli
What type of epithelium is the respiratory epithelium?
Pseudostratified Columnar Ciliated
What are the 5 cells types found in a majority of the respiratory epithelium?
- Ciliated Columnar cells
- Goblet cells
- Brush cells
- Small granule cells
- Basal cells
What cell type makes up a majority of the respiratory epithelium?
Ciliated Columnar cells
What cell type in the respiratory epithelium are chemosensory cells with microvilli connected to sensory nerve fibers?
Brush cells
What cell type in the respiratory epithelium are a part of the DNES (diffuse neuroendocrine system)?
Small granule cells - secret granules
What cell type in the respiratory epithelium are stem cells that line the basement membrane?
Basal cells
What are the 3 regions of the nasal cavities?
- Nasal vestibule
- Respiratory region
- Olfactory region
Where at and what type of epithelium is the nasal vestibule?
Just inside the nostrils
Keratinized stratified squamous
Where at and what type of epithelium is the respiratory region of the nasal cavities?
Inferior 2/3
Pseudostratified columnar ciliated (respiratory mucosa)
Where at and what type of epithelium is the olfactory region of the nasal cavities?
Superior 1/3 Pseudostratified columnar ciliated with a few differences - Dramatically thicker - NO GOBLET CELLS - Nonmotile cilia
What are the unique features of the olfactory region of the nasal cavities epithelium?
Pseudostratified columnar ciliated
- Thicker
- NO GOBLET CELLS
- Nonmotile cilia
- Olfactory (Bowman’s) glands
What do Olfactory (Bowman’s) glands secrete in the nasal cavity?
Serous product to dissolve odorant molecules
What 4 cell types will you find in the olfactory region of the nasal cavities?
- Olfactory Receptor Neurons (ORNs)
- Basal cells
- Brush cells
- Sustentacular cells
Describe brush cells in the olfactory region of the nasal cavities
Ciliated columnar cells that are in contact with CNV
- chemosensory cells
Describe sustentacular cells in the olfactory region of the nasal cavities
Mechanical and metabolic support for the ORNs
Describe ORNs
Single dendritic process with odorant receptors
- ligand binding causes action potential
What is the main function of the nasal cavities?
Adjust temperature and humidity of inspired air
What are paranasal sinuses?
Air-filled spaces in the bones of the walls of the nasal cavity
What type of epithelium is in the paranasal sinuses?
Respiratory epithelium - pseudstratified columnar ciliated
Paranasal sinuses communicate with the nasal cavities via openings in the mucosa. How does mucous from the paranasal sinuses get to the nasal cavities?
Ciliary movements
What are often subject to acute infections after a viral upper respiratory tract infection?
Paranasal sinuses
- sometimes physically drained
Function of larynx?
Passage of air between pharynx and trachea
The larynx is reinforced with cartilage and some skeletal muscle that reinforces phonation. What are the types of cartilage found?
Hyaline
Elastic
Function of Epiglottis?
Prevent swallowed food/fluid from entering the trachea (airway)
Describe the important features of the epiglottis?
- Core of ELASTIC cartilage
- Lingual surface = stratified squamous
- Laryngeal surface = pseudostratified columnar ciliated
- Mixed glands beneath epithelium
The epiglottis has 2 surfaces each with different epithelium. List those surfaces and their corresponding epithelium
- Lingual surface = stratified squamous
2. Laryngeal surface = pseudostratified columnar ciliated
What type of epithelium is the vestibular folds?
Respiratory epithelium
Are the vestibular folds movable?
NO
What type of epithelium is the vocal folds?
Nonkeratinized stratified squamous
Purpose of the vocal folds?
Protects from abrasion and used for sound production!
Laryngitis
Inflammation of the larynx - changes shape of vocal folds and causes hoarseness
Croup
Childhood form of laryngitis - causes hoarseness and loud, harsh, cough
The trachea extends from the larynx and divides into?
Main (primary) bronchi
Why does the lumen of the trachea remain open?
Due to the cartilagenous rings
What type of mucosa is found at the trachea?
Pseudostratified columnar ciliated
What is found in the submucosa layer at the trachea?
Dense CT; houses the hyaline cartilage partial rings and TONS OF GLANDS
Serosa or adventitia for the trachea?
Adventitia
What type of muscle sits posteriorly on the trachea and spans the open ends of the hyaline cartilage rings?
Trachealis muscle - smooth muscle
The trachea splits into primary bronchi that enter each lung. The primary bronchi will differentiate into?
Secondary bronchi
Tertiary bronchi
Bronchioles
Terminal Bronchioles
Describe the mucosa of the bronchi
Pseudostratified columnar ciliated
- shorter cells with fewer goblet cells
- Abundant glands
As you move down the bronchi, what happens to the cartilage rings?
They are gradually replaced with hyaline cartilage PLATES as the lumen size decreases
What does the lamina propria contain in the bronchi?
Spiral smooth muscle
Bronchioles arise from?
Tertiary bronchi
The bronchioles enter ______ and branch to form 5-7 ______
Pulmonary lobule
Terminal bronchioles
The larger bronchioles have what type of mucosa?
Pseudstratified columnar ciliated
As bronchioles get closer to the terminal bronchioles, what happens to the mucuosa?
Transitions from the respiratory epithelium:
Pseudostratified columnar ciliated
–> simple columnar
–> simple cuboidal at terminal bronchioles
What are bronchioles lacking?
NO CARTILAGE, GLANDS and submucosa
What layer is prominent in the bronchioles?
Muscularis layer of smooth muscle
Asthma
Recurrent obstruction of air due to bronchiole inflammation and smooth muscle constriction (bronchospasm)
What part of the respiratory tract is inflamed with asthma?
Bronchioles
Symptoms of asthma?
Wheezing, coughing, shortness of breath and chest tightness
Describe the bronchiole changes associated with asthma
THICK bronchiolar wall and basement membrane
Increased goblet cells, eosinophils, mast cells and lymphocytes
- hyperplastic smooth muscle
– Enlarged blood vessels
What type of epithelium are terminal bronchioles?
Simple cuboidal
What is the predominant cell type in the terminal bronchioles?
Club cells
Describe the appearance of club cells
Dome shaped with secretory granules
What are the 3 functions of club cells in the terminal bronchioles?
- Produce surfactant
- Detoxification of inhaled compounds
- Secretion of antimicrobial peptides for immune defense
What does a terminal bronchiole then divide into?
2 or more respiratory bronchioles
What is the 1st part of the respiratory region?
Respiratory bronchioles
What type of epithelium is at the respiratory bronchioles?
Simple cuboidal
Respiratory bronchioles give rise to?
Alveolar ducts
What type of cells line alveolar ducts?
squamous
What form around alveolar ducts?
Alveolar rings - smooth muscle, collagen, elastic fibers
Large clusters of 2 or more alveoli that form ends of alveolar ducts
Alveolar sacs
Alveoli are lined by what type of epithelium?
Simple squamous
What permit movements of air between alveoli?
Alveolar pores
What is found in between alveoli?
Interalveolar septum
Interalveolar septum contains?
Capillaries
Elastic fibers - permit inhalation
Reticular fibers - prevent collapse
What cells line alveoli?
Type 1 and Type 2 alveolar cells
What alveolar cells participate in gas exchange?
Type 1 alveolar cells
What alveolar cells produce surfactant and bulge into the alveolus?
Type 2 alveolar cells
What are the qualities of a type 2 alveolar cell?
Line SOME of the alveolus, round, bulge into the alveoli
What separates air in the alveoli from the blood?
Respiratory membrane = air-blood barrier
What makes up the respiratory membrane?
- 2/3 attenuated (thin) cells lining alveolus
- FUSED basal lamina of capillary endothelium and attenuated cells
- Thin, endothelial capillary cells
Emphysema
Permanent enlargement of air spaces distal to terminal bronchiole
- obstruction of air flow and destruction of alveolar wall
What can increase your risk of emphysema?
Smoking, chronic inhalation of particulate material
What are lost with emphysema?
Some areas of gas exchange
Pneumonia
Inflammation of lung tissue
- air spaces fill with exudate (RBCs, WBCs, fibrin)
How does the lung appear with pneumonia?
Red, firm (lack of air spaces), heavy (exudate)
