L27. Respiratory 2

Question 1

Describe the bronchi

Answer 1

1. bifucation of the trachea
2. branches ~8 times in each lung
3. diameter decreases with each branching
4. pulmonary arteries and pulmonary veins run along the adventitia layer

Question 2

What are the trends seen in branching?

Answer 2

1. decrease in the diameter as we branch
2. decrease in the amt of cartilage from rings to plates in the adventitia
3. increase in the amount of smooth muscles and elastic tissue between the ,Desmucosa and submucosa layer, and lamina proproa respec
4. decrease in the amount of submucosal seromucosal glands and goblet cells
5. decrease in the height of the epithelial cells

Question 3

Describe the bronchioles

Answer 3

1. bronchioles are continuous with the bronchi
2. they branch ~6 more times before reaching terminal bronchiole
3. no longer have cartilage
4. no goblet cells to produce seromucosal secretions – keeps airways clear
5. Clara cells secretes lipoprotein, lowers surface tension and keeps bronchioles open
6. simple columnar/cubodial epithelium
7. elastic tissue and smooth muscles are prominent

Question 4

Describe the bronchiolar epithelium

Answer 4

simple columnar epithelium
no goblet cells
contains Clara cells and ciliated cells

Question 5

Describe the Clara cells

Answer 5

• apically secrete ( through exocytosis) lipoprotein secretions
• secretion is anti-inflammatory and is a lubricant
• has a prominent SER for detoxification enzymes

Question 6

What are the 2 sites for the respiratory portion of the respiratory system?

Answer 6

Respiratory bronchioles

alveolar proper

Question 7

Describe the respiratory bronchioles

Answer 7

discontinuous bronchiolar tissue that are interuppted by alveolar air sacs
-some gas exchange here

Question 8

Describe the alveolar proper

Answer 8

• most of the gas exhcange between the alveolar capillaries occur here
• cluster of alveolar ducts at the terminal ends of the respiratory brinchioles
• composed of simple epithelilum with a thin lamina propria between adjacent alveoli forming the interalveolar septim (made up of reticular connective tissue with elastic fibers)

Question 9

Describe the epithelium of the alveolus

Answer 9

contains a mix of simple squamous and cubodial pneumocytes

Question 10

Describe the submucosa layer of the alveolus

Answer 10

• little or no smoothe muscles
• contains elastic fibers required for recoil
• some reticular connective tissue between the alveoli (interalveolar septum)

Question 11

Describe the adventitia layer of the alveolus

Answer 11

sparse

Question 12

What is the function of the alveolar pore

Answer 12

connecting pores between adjacent alveoli facilitate air pressure equalization

Question 13

Describe the simple squamous pnemocytes

Answer 13

responsible for site of gas exchange

• simple squamous epithelium with tight junctions
• tight junctions also seen in the endothelial
• fused basal lamina between the simple squamous pnemocytes and the capillary enothelial

Question 14

Describe the cubodial pneumocytes

Answer 14

• interspersed between the type 1 pneumocytes
• secretes phospholipoprotein (surfactant) apically ,keeps the alveolus open by lowering surface tension
• lamellor bodies contains these surfactant, they are secretory bodies

Question 15

What are dust cells

Answer 15

-macrophages that phagocytose particulate matter within the alveloli

Question 16

What happens when there is a chronic activation of dust cells

Answer 16

• breakdown of the elastic reticular component of the lamina propria
• causes loss of the interalveolar septa: functional loss of alveoli

Question 17

Emphysema

Answer 17

scarring of the interalveolar septa, lost of elasticity and reticular fibers
loss of alveolar tissue
does not regenerate even though there may be stem cells