PULMONARY PHYSIOLOGY
INTRODUCTION
‐ Air movement between the environment & cells
‐ Functions of the respiratory system:
• Exchange of gases between environment & blood (O2 and CO2)
• Homeostasis (body pH → equilibrium)
• Protection against pathogens
• Vocalisation
‐ Respiration: transport of oxygen from outside air to cells and transport of
Carbon Dioxide from cells to the outside
‐ Without food = 3 weeks
‐ Without water = 3-4 days
‐ Without oxygen = 3-6 minutes
‐ Respiratory main function
• O2 ↔ CO2
STRUCTURAL CLASSIFICATION
ALYSSA THERON
,FUNCTIONAL CLASSIFICATION
STRUCTURE AND FUNCTION
‐ Nose and nasal cavity
‐ Pharynx
‐ Larynx
‐ Trachea
‐ Bronchi tree
‐ Upper and lower respiratory airways
NOSE AND NASAL CAVITY
‐ External nose – nose
‐ Internal nose – nasal cavity
‐ Lined with mucous membrane: contains ciliates epithelium and mucous
secreting goblet cells
‐ Rich blood supply
• Dilation of nasal blood vessels (cold/ flu, allergy, toxins) – oedema of
mucous membranes obstruct airways
ALYSSA THERON
, ‐ Nasal cavity: functions of mucous membrane
• Warms air
• Moistens/ humidifies incoming air (so doesn’t dry out)
• Filters incoming air – nose hairs guard nostrils.
Cilia and sticky mucous entrap dust & microorganisms
Cilia moves mucous that has entrapped these microorganisms
towards pharynx where they can be swallowed/ coughed out
PHARYNX (THROAT)
‐ Functions as common passage for:
• Transport of food from oral cavity – oesophagus
• 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 and causing choking
** hypo-pharynx is also known as laryngeal pharynx
LARYNX (VOICE BOX)
‐ Continuous – trachea (superior)
‐ The functions of the larynx:
• To act as a switching mechanism to route air and food into the proper
channels
• Voice production
‐ Inner surface of larynx – mucous membrane (has goblet cells that produce
mucous)
ALYSSA THERON
, TRACHEA (WINDPIPE)
‐ Larynx → trachea → primary bronchi
‐ C-shaped cartilaginous rings: gives firmness to the wall, prevents airways
from collapsing
‐ Mucous membrane: lined with ciliated epithelium
‐ Also responsible for filtering incoming air
BRONCHIAL TREE
‐ Trachea → right & left primary bronchi
‐ Bronchi – lined with ciliated columnar epithelium
‐ Secondary bronchi → tertiary bronchi → bronchioles → terminal
bronchioles → respiratory bronchioles → alveolar ducts
‐ Smooth muscle & elastic fibers – allow expansion and recoiling to increase/
decrease airflow in structures
‐ branching becomes more numerous then walls think out – alveoli design
allows for increased surface area
‐ More branches = smaller structures & smaller walls, therefore increased
surface area
ALYSSA THERON
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 EFT, 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 this summary from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller ath101. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy this summary for R180,00. You're not tied to anything after your purchase.