Intro to respi physio and pathophysio

Question 1

What are the fns of the respiratory sys?

Answer 1

Metabolism and acid-base regulation
- provide O2 to tissues for metabolism
- remove CO2 and regulates pH
- CO2 convert into carbonic acid -> add to acid load -> unfavourable for cells to fn
- CO2 is by product of cellular metabolism

Endocrine fn
- produces hormones (eg: angiotensin 2)

Immunological fn
- clearance of irritants and potential pathogens

Voice pdtn by larynx (voice box) -> coordinated w/ breathing

Question 2

Where does the lower respiratory tract start and what respi sys organs are part of it?

Answer 2

Start at opening of larynx

Organs involved:
- larynx
- trachea
- bronchus
- pleura
- bronchioles
- alveoli

Question 3

What organs are part of the upper respiratory tract?

Answer 3

Epiglottis

Pharynx

Nasal cavity

Question 4

What is the epiglottis responsible for?

Answer 4

Swallowing reflex
- close when swallow food -> divert food to esophagus
- protect URT from food particles

Question 5

Musculature of trachea

Answer 5

Mainly cartilage

Question 6

Musculature of bronchi

Answer 6

Cartilage

Little smooth muscle

Question 7

Musculature of bronchioles up to terminal bronchioles

Answer 7

Mainly smooth muscle

Question 8

Innervation of bronchi and bronchioles

Answer 8

Muscles innervated by autonomic nervous system (sympathetic and parasympathetic) and other nerves (non-adrenergic/non-cholinergic nerves)

Question 9

What are alveoli?

Answer 9

Sites of gas exchange -> wide surface area

Air sacs at end of bronchioles

Question 10

Blood supply to alveoli

Answer 10

Rich supply of capillaries

Question 11

Histological features of alveoli

Answer 11

Interstitial space

Alveolar macrophages

Type 2 cell

Type 1 cell

Capillary

Question 12

What makes up the interstitial space in alveoli and the purpose of it?

Answer 12

Components:
- elastic, collagen fibres
- few fibroblasts

Purpose -> support alveoli and fn in lungs

Question 13

Fn of alveolar macrophages

Answer 13

Immunity -> ingest particles/bacteria

Question 14

Fn of type 2 cell

Answer 14

Produce surfactant

Question 15

Fn of type 1 cell

Answer 15

Alveolar epithelium

Question 16

How does gas exchange occur?

Answer 16

Via diffusion across thin barrier
- movement is dynamic and constant
- inhale: O2 move from alveolus -> capillary blood
- exhale: CO2 move from capillary blood -> alveolus

Question 17

What is effective oxygenation and CO2 removal from lungs and body tissues dependent on?

Answer 17

Ventilation
- movement of air into and out of respi tract

Gas exchange at alveoli in lungs
- whether diffusion of gas is effective

Perfusion of alveoli in lungs
- blood supply

Circulation of tissues

Question 18

How is the respi epithelium (mucosa) of airways protected?

Answer 18

Humidification and warming of air in upper passages

Mucous secretion

Question 19

How are some protective mechanisms of the lungs?

Answer 19

Airway reflexes
- cough, sneeze, swallowing reflex

Mucociliary trapping of foreign matter

Ciliary escalator

Alveolar macrophages

Question 20

Why do we cough?

Answer 20

Response to irritation of larynx, trachea, bronchi

Question 21

Mechanism of cough

Answer 21

Deep inspiration followed by forceful expiration against closed glottis -> glottis suddenly opens -> explosive outflow of air to expel irritants/mucus through pharynx and mouth

Question 22

Why do we sneeze?

Answer 22

Response to irritation of nasal mucosa

Question 23

Mechanism of sneeze

Answer 23

Similar to cough
- ejects irritants/mucus through nose

Question 24

Components of the ciliary escalator

Answer 24

Cilia

Epithelial cell

Goblet cell

Question 25

What does the goblet cell do?

Answer 25

Secrete mucus

Question 26

Fn of ciliary escalator

Answer 26

Cilia beat to move particles and mucus away from lung to upper respiratory tract