Biological Role of Respiration, Histology and Defense Mechanisms

Question 1

Main compartments of the respiratory system

Answer 1

1. conduction zone
2. respiratory zone
3. musculo-elastic ventilation apparatus

Question 2

Conduction zone

where and role?

Answer 2

conditioning of inhaled air

neck

Question 3

Respiratory zone

where and role?

Answer 3

site of gas exchange

lungs

Question 4

Musculo-elastic ventilation apparatus role

Answer 4

drives ventilation

Question 5

What happens to the structure of the airways and vessels as they progress?

Answer 5

divide into successions of bifurcations

Question 6

What is mucosa?

Answer 6

membrane that lines the nasal cavity
made of layers of epithelial cells overlying a layer of loose connective tissue
lined by lymphoid tissue all the way

Question 7

Types of sinuses

Answer 7

maxillary sinus - cheekbone
ethmoid sinuses
sphenoid sinus
frontal sinus

Question 8

How is turbulence created?

Answer 8

turbinate bones in nasal cavity which form narrow passageways
drives air in and out of sinuses

Question 9

Defence mechanisms against particles

Answer 9

vibrissae prevent large particles entry

mucus which covers lining trap smaller particles

Question 10

Respiratory epithelium characteristics

Answer 10

lots of goblet cells

below epithelium: sponge-like mucosa, due to extensive venous plexus

Question 11

Actions of venous plexus in mucosa

Answer 11

mediate exchange of moisture with the air
filling status regulates flow of air through nasal cavities
swell during infections of nasal cavity

Question 12

Other epithelium in nasal cavity

Answer 12

olfactory which conveys sense of smell

top of nasal cavity

Question 13

Histology of trachea

Answer 13

horse shoe shaped cartilage
seromucous glands in submucosa
smooth muscle completes rings partially formed by cartilage
pseudostratified ciliated epithelium with mucous producing goblet cells

Question 14

What is mucociliary clearance?

Answer 14

mucus transported towards pharynx by beating movement of cilia

Question 15

Bronchus histology

Answer 15

cartilage which varies between generations
1st: several rods spanning most of circle
later: single small plate
lumen bordered by respiratory epithelium
sometimes - incomplete ring of smooth muscle between epithelium and cartilage
may be submucosal glands

Question 16

Difference between bronchi and larger bronchioli

Answer 16

bronchioli: no cartilage , complete smooth muscle, no submucosal glands, fewer goblet cells in epithelium

Question 17

Histology of smaller bronchioli

Answer 17

epithelium is cuboidal with ciliated and non-ciliated club cells
complete ring of smooth muscle
higher ratio of muscle ring thickness to luminal diameter than bronchi

Question 18

Club cells role

Answer 18

protective role

generate serous secretions

Question 19

What do terminal bronchioles do?

Answer 19

give rise to respiratory bronchioles that have cuboidal epithelium and alveoli built in their walls

Question 20

Characteristics of tissue around alveoli and nearby airways

Answer 20

connective tissue contain numerous elastin fibres

Question 21

What do alveoli have to make gas exchange more efficient?

Answer 21

alveolar pores - allows quicker filling as it dampens turbulence of air

Question 22

What is the blood-air barrier?

Answer 22

space which oxygen crosses to enter the lungs

Question 23

What is the blood-air barrier made of?

Answer 23

ultra thin walls of capillary endothelium and type 1 cells (pneumocyte)

Question 24

Pulmonary arteries function and structure

Answer 24

provide blood supply to alveolar capillary networks

elastic arteries with comparatively thin walls

Question 25

Bronchial circulation role and structure

Answer 25

provide blood supply to bronchi from the aorta

small, strong muscular wall, little elastin

Question 26

What is surfactant?

Answer 26

compound made of phospholipids, proteins and carbohydrates

made by type 2 alveolar cells

Question 27

What does surfactant do?

Answer 27

reduce surface tension so water in the alveolar surafce does not exert strong capillary forces so expansion of the lung is not inhibited

Question 28

Distinguishing type 1 pneumocyte

Answer 28

only nuclei discernible, flat at air interface

looks similar to flat endothelial cells

Question 29

Distinguishing endothelial cells

Answer 29

ideally: nucleus curved around capillary

looks similar to type 1 pneumocyte

Question 30

Distinguishing type 2 pneumocytes

Answer 30

corners of alveoli, roundish cells with light content and light granular nuclei

Question 31

Distinguishing macrophages

Answer 31

within alveoli
larger than type 2 pneumocytes
cytoplasm often dirty
nuclei larger than type 2 pneumocytes with heterochromatin spots

Question 32

Where are the lymph vessels of the lungs?

Answer 32

in the septa next to the vessels of pulmonary circulation

also in the interstitial layer adjacent to the pleura

Question 33

Where can carbon be deposited?

Answer 33

lymph nodes and macrophages

Question 34

What is Waldeyer’s Ring?

Answer 34

series of tonsils (aggregates of lymph follicles) at the anterior pharynx, very close under surface of the skin

Question 35

Defense against pathogens in the airways and alveoli

Answer 35

mucus of airways contain immunoglobulins, mainly IgA

alveoli: alveolar macrophages