Intro to respi physio and pathophysio Flashcards
What are the fns of the respiratory sys?
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
Where does the lower respiratory tract start and what respi sys organs are part of it?
Start at opening of larynx
Organs involved:
- larynx
- trachea
- bronchus
- pleura
- bronchioles
- alveoli
What organs are part of the upper respiratory tract?
Epiglottis
Pharynx
Nasal cavity
What is the epiglottis responsible for?
Swallowing reflex
- close when swallow food -> divert food to esophagus
- protect URT from food particles
Musculature of trachea
Mainly cartilage
Musculature of bronchi
Cartilage
Little smooth muscle
Musculature of bronchioles up to terminal bronchioles
Mainly smooth muscle
Innervation of bronchi and bronchioles
Muscles innervated by autonomic nervous system (sympathetic and parasympathetic) and other nerves (non-adrenergic/non-cholinergic nerves)
What are alveoli?
Sites of gas exchange -> wide surface area
Air sacs at end of bronchioles
Blood supply to alveoli
Rich supply of capillaries
Histological features of alveoli
Interstitial space
Alveolar macrophages
Type 2 cell
Type 1 cell
Capillary
What makes up the interstitial space in alveoli and the purpose of it?
Components:
- elastic, collagen fibres
- few fibroblasts
Purpose -> support alveoli and fn in lungs
Fn of alveolar macrophages
Immunity -> ingest particles/bacteria
Fn of type 2 cell
Produce surfactant
Fn of type 1 cell
Alveolar epithelium
How does gas exchange occur?
Via diffusion across thin barrier
- movement is dynamic and constant
- inhale: O2 move from alveolus -> capillary blood
- exhale: CO2 move from capillary blood -> alveolus
What is effective oxygenation and CO2 removal from lungs and body tissues dependent on?
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
How is the respi epithelium (mucosa) of airways protected?
Humidification and warming of air in upper passages
Mucous secretion
How are some protective mechanisms of the lungs?
Airway reflexes
- cough, sneeze, swallowing reflex
Mucociliary trapping of foreign matter
Ciliary escalator
Alveolar macrophages
Why do we cough?
Response to irritation of larynx, trachea, bronchi
Mechanism of cough
Deep inspiration followed by forceful expiration against closed glottis -> glottis suddenly opens -> explosive outflow of air to expel irritants/mucus through pharynx and mouth
Why do we sneeze?
Response to irritation of nasal mucosa
Mechanism of sneeze
Similar to cough
- ejects irritants/mucus through nose
Components of the ciliary escalator
Cilia
Epithelial cell
Goblet cell
What does the goblet cell do?
Secrete mucus
Fn of ciliary escalator
Cilia beat to move particles and mucus away from lung to upper respiratory tract
