Summary
Summary FLG221 Pulmonary physiology
- Course
- Institution
FLG221 Renal physiology
[Show more]
Seller
Follow
LizeMostert
Content preview
FLG 221: Pulmonary PhysiologyIntroduction
- Air movement between environment and cells
- Functions of the respiratory system:
1. Exchange of gases between environment and blood (CO2 and O2)
2. Homeostasis (body pH)
3. Protection against pathogens
4. Vocalization
- Without food for 3 weeks
- Without water for 3 – 4 days
- Without oxygen for 3 – 6 minutes after which brain damage and death results
- Respiratory system main function: O2 ↔ CO2
Structural classification
Functional classification
,Structure and function:
1. Nose and nasal cavity
2. Pharynx
3. Larynx
4. Trachea
5. Bronchi tree
6. Upper and lower respiratory airways
Nose and nasal cavity
- Lined with mucous membrane: contains ciliated epithelium and
mucous secreting goblet cells (mucous traps debris)
- Rich blood supply. Dilation of nasal blood vessels (cold/flu, allergy,
toxins) → oedema of mucous membranes → obstruct airways
Nasal cavity:
Functions of mucous membrane:
- Warms air (protects airway)
- Moistens/humidifies incoming air (prevents dehydration)
- Filters incoming air: nose hairs guard nostrils. Cilia and sticky mucous
entrap dust and microorganisms (cilia move debris towards pharynx)
Pharynx (throat)
- Functions as common passage for:
o transport of food from oral cavity → oesophagus
o transport of air from nasal cavity → larynx
- During swallowing soft palate is raised reflexly: prevents food from entering nasal cavity. Larynx is
elevated and breathing is inhibited reflexly: prevents food entering trachea → “choking
Larynx (voice box)
- Continuous → trachea (superior)
- The functions of the larynx:
o To act as a switching mechanism to route air (lowered) and food (elevated) into the proper
channels
o Voice production
- Inner surface of larynx: mucous membrane
, o Traps debris not filtered by nasal cavity
Trachea (windpipe)
- Larynx → Trachea → Primary Bronchi
- C-shaped cartilaginous rings: gives firmness to the wall, prevents airways from collapsing
- Mucous membrane: lined with ciliated columnar epithelium (contain goblet cells)
- Also responsible for filtering incoming air (mucous traps, cilia propels)
Bronchial tree
- Trachea → Right and Left primary bronchi
- Bronchi: lined with ciliated columnar epithelium
- Secondary bronchi → tertiary bronchi → bronchioles → terminal bronchioles (transition of conducting
to respiratory zone where gas exchange takes place)→ respiratory bronchioles (smooth muscle)→
alveolar ducts
- Smooth muscle & elastic fibres
As branching becomes more numerous the wall thins out. Alveoli design allows for increased surface area
The conducting airways
- The upper airways and bronchi condition air before → alveoli.
- Conditioning:
- Warming of air (37C): Ensures core body temp does not change & alveoli not damaged by cold air
- Adding water vapour (humidifying – prevents dehydration)
- Filtering out foreign material: ↓ viruses, bacteria & foreign inorganic particles so do not reach alveoli
(throughout airway)
Cells of the conducting airways
1. Ciliated columnar epithelial cells: mucociliary movement. Sweep foreign substances upwards
(towards pharynx)
2. Mucus secreting goblet cells: produce mucins. Mucins play added role in innate immunity of mucosa –
proteins
3. Serous cells: found in airway epithelium. Produce lysozymes, IgA – antimicrobials
4. Clara cells: found in bronchioles. Produce antiinflammatory substances (phospolipase A2 inhibitor)
5. Other cells: neuroendocrine cells (regulate smooth muscle function and growth)
, Lungs
- Lungs: exchange surface
o Surface area: 75 m2
o Thin walled
o Moist
o Enclosed by pleural membranes (pleural fluid – in between)
- Occupy most of the thoracic cavity
- Ribs & skin protect
- Right lung three lobes Left lung two lobes
The Pleura
- A double-layered sac surrounding each lung
o Parietal pleura - outer membrane which is attached to the inner surface of the thoracic wall
o Visceral pleura - membrane that covers the surface of each lung (inner membrane)
- Pleural fluid
o forms a pleural seal that holds the outer surface of the lungs against the inner surface of the
thoracic wall
o Reduces friction between pleural membranes
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller LizeMostert. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $2.92. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
79271 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now