the respiratory tract

Question 1

how are the airways designed

Answer 1

branching tree of blind ending tubes

Question 2

what is the function of the respiratory system

Answer 2

• gas exchange and trasport (O2 and CO2)
• metabolic functions (synthesis of surfactant, synthesis and release of histamine, uptake and inactivation of compounds , activation of angiotensin by ACE)
• body temp regulation
• body acid-base regulation
• vocalisation and display
• facilitates venous return to the heart

Question 3

what are the 2 types of airways in the mammalian lung and how do they work

Answer 3

conducting: moves air in and out of the lung (No gas exchange occurs here
respiratory: includes the respiratory bronchioles and alveoli and moves the respiratory gases, that is oxygen and carbon dioxide, in and out of the blood

Question 4

What structures are part of the conducting zone?

Answer 4

• Nasal cavities
• Oral cavity
• Pharynx
• Larynx
• trachea
• bronchi
• most bronchioles

Question 5

what is the function of the nasal cavities

Answer 5

humidify, warm, filter, and act as a conduit for inspired air, as well as protect the respiratory tract through the use of the mucociliary system.

Question 6

what is the function of the oral cavity

Answer 6

to supplement or replace the nasal cavity’s functions when needed.

Question 7

what is the function of the larynx

Answer 7

protect the lower respiratory tract from aspirating food into the trachea while breathing. it also contains the vocal cords and functions as a voice box for producing sounds

Question 8

what is the function of the pharynx

Answer 8

aka the throat: carries air from nose and mouth

Question 9

what is the function of the trachea

Answer 9

carries air in and out of the lungs.
- stiff flexible tube for oxygen to reliably flow through

Question 10

what is the function of the bronchi

Answer 10

carries air in and out of lungs. also healp moisturize the air you breath and screen out foreign particles

Question 11

what is the function of the bronchioles

Answer 11

delivers air to alveoli

Question 12

label the letters on this histological cross section of the trachea

Answer 12

Question 13

label

Answer 13

Question 14

describe the pathway of air through the airways

Answer 14

nasal cavities/mouth => pharynx => tranchea => primary bronchi => bronchioles => terminal bronchioles => respiratory bronchioles => alveolar ducts => alveolar sacs

Question 15

list the defence mechanisms of the respiratory system

Answer 15

• filtration
• reflexes
• fluid lining
• mucociliary escalator
• detoxification mechanisms

Question 16

label this histological section of the bronchus

Answer 16

E: respiratory epithelium
LP: lamina propria (loose, highlt vascular supporting tissue
M: mucous
S: serous mucous
G: seromucinous glands
C: cartilage

Question 17

label this cross section of bronchiole

Answer 17

V: vasculature
M: smooth muscle

Question 18

describe the features of the alveolar ducts

Answer 18

• has alveoli which open on all its sides
• has no walls
• calibre of the alveolar duct is substantially greater than that of the respiratory bronchiole
• openings gaurded by rings of smooth muscle

Question 19

describe the features of the alveolar sacs

Answer 19

• rotunda-like area on the end of the alveolar duct
• usually there is a cluster of alveolar sacs at the end of one alveolar duct

Question 20

label this histological section of the terminal portion of the respiratory tree

Answer 20

Question 21

describe the shape, dimensions, wall, pulmonary capillaries, blood gas barrier and fibre skeleton of the alveoli

Answer 21

shape: minute polygonal chambers
dimensions: diameter changes with inflation and deflation of the lung. varies with size of animal
wall: two outermost surfaces are formed from alveolar epithelial cells
Pulmonary capillaries: network of alveolar capillaries lie between the two epithelial sheets.
Blood gas barrier: single basal lamina.
Fibre ‘skeleton’: connective tissue cells & fibres form alveolar interstitium. This includes a ‘skeleton’ of collagen fibrils and elastic fibres.

Question 22

what do the letters indicate on this alveolar cross section

Answer 22

Question 23

which cells produce surfactant

Answer 23

alveolar type 2 cells (type 2 epithelium)

Question 24

What is the role of surfactant?

Answer 24

A compound that lower the surface tension between two different states, between a gas and a liquid etc.

Question 25

What is the role of angiotensin?

Answer 25

Peptide hormone that causes vasoconstriction and an increase in blood pressure.

Question 26

label

Answer 26

A: Bronchi

B: Bronchioles

C: Respiratory bronchioles

D: Alveolar ducts

E:Alveolar sacs

F: Alveoli