PGY 300 Respiratory Physiology Review
Interactions of Major Organ System of Human Body ○ Respiration involves ventilation (breathing), gas exchange (between air and capillaries in lung or systemic capillaries and tissues of body), and oxygen utilization (cellular respiration) ○ Respiration as ...
● Interactions of Major Organ System of Human Body
○ Respiration involves ventilation (breathing), gas exchange (between air and capillaries in lung or
systemic capillaries and tissues of body), and oxygen utilization (cellular respiration)
○ Respiration as two separate processes: gas exchange and cellular metabolism
■ Pulmonary respiration: primarily obtain oxygen for use via cells of body and to eliminate
carbon dioxide produced by cells
● Pulmonary gas exchange: ventilation (between atmosphere and alveoli)
○ Diffusion: transport over short distances
○ Convection (bulk flow): transport over long distances
○ Both diffusion and convection driven by pressure differences
■ Cellular respiration: set of metabolic reactions within cell or organism converting nutrient
biochemical energy into adenosine triphosphate (ATP)
○ Four integrated processes for respiration
■ Ventilation (breathing): inspiration and expiration
■ Exchange of O2 and CO2 between lungs and blood
■ Transport of O2 and CO2 in blood
■ Exchange of gases between blood and cells
■ Diseases affecting respiration can occur at any of these processes
● Anaerobic and Aerobic Respirations
○ Anaerobic respiration: glycolytic metabolism or glycolysis
■ No oxygen used; no carbon dioxide produced; but only small amount of ATP produced
○ Aerobic respiration
■ Glycolysis in cytoplasm; citric acid cycle in mitochondria
■ Net gain: 30~38 ATP
■ Energy consumption of skeletal muscle cells increases up to 100-fold when going from rest
to high-intensity exercise
○ Cytoplasm and mitochondria
■ ATP-phosphocreatine system (cytoplasm)
■ Anaerobic ATP generation: glycolysis → oxygen-independent ATP generation (cytoplasm)
■ Aerobic ATP generation: oxidative phosphorylation → oxygen-dependent ATP generation
(mitochondria)
○ Humans surrounded by air with plenty of oxygen (21%)
■ Necessary to have pulmonary and circulatory systems
○ Earth worm: gas diffusion takes place through thin skin
■ O2 diffuses in and CO2 diffuses out
■ Blood vessels absorb the O2 and carry it to body
○ Diffusion
■ Fick’s second law of diffusion: 𝜕C/𝜕t = D (𝜕2C/𝜕x2)
■ Diffusion time (t) ≈ x2/(2D)
● 𝑡 = elapsed time since diffusion began
, ● 𝑥 = mean distance traveled by diffusing solute in one direction along one axis after
elapsed time (t)
● D = diffusion coefficient of a solute in free solution
○ Units of area/time (e.g. cm2/s)
● Major Functions of Respiratory System
○ Exchange of gases between atmosphere and blood
○ Warm air to body temperature (37°C)
○ Adding water vapor until inspired air reaches 100% humidity.
○ Filtering out foreign material such as particulates (dust, pollen, smoke), viruses, or bacteria
○ Vocalization
● Organization of Respiratory System
○ Lungs and thoracic cavity
■ Respiratory system divided into upper and lower regions
● Upper: nasal cavity, pharynx, tongue, vocal cords, larynx, and esophagus
● Lower: trachea, left and right lungs, diaphragm, and left and right bronchi
● Left lung divided into two lobes (superior and inferior with cardiac notch), right
lung divided into three lobes (superior, middle, and inferior)
○ Lobes of lung increase flexibility
○ 60% of total lung volume found in right lung
○ Each lung enclosed in two pleural membranes; esophagus and aorta pass
through thorax between pleural sacs
■ Pleural sacs enclose lungs (double membranes including parietal and
visceral): fluid filled (25~30 ml); provide a slippery surface; holds
lungs tight against thoracic wall due to cohesiveness of water
■ Muscles of thorax, neck, and abdomen create force to move air during breathing
● Inspiration: sternocleido-mastoids, scalenes, external intercostals, and diaphragm
● Expiration: internal intercostals and abdominal muscles
● Between ribs: internal and external intercostals
○ Respiratory tract = conducting zone + respiratory zone
■ Bronchi and alveoli
● Branching of airways creates about 80 million bronchioles
● Each alveoli cluster surrounded by elastic fibers and network of capillaries
● Deoxygenated blood enters via pulmonary artery
● 80-90% of alveolar surface covered by capillaries
● Alveoli as site of gas exchange: blood supplies to air sac; alveoli and capillary
network allowing gas exchange with red blood cells
○ Type I alveolar cell for gas exchange
○ Endothelial cell of capillary
○ Type II alveolar cell synthesizes surfactant
○ Limited interstitial fluid
○ Alveolar macrophage ingests foreign material
● Conducting zone: non-collapsible airway; cartilaginous rings; hyaline
cartilage; no gas exchange
○ Including larynx, trachea (branches into two primary bronchi), cartilage
ring, left and right primary bronchus (divides 22 more times terminating in
cluster of alveoli), and secondary bronchus
● Respiratory zone: collapsible airway; gas exchange
○ Including bronchiole (terminal and respiratory) and alveoli
○ Chronic obstructive pulmonary disease (COPD)
■ Common chronic disease with increasing prevalence (5% of global population)
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 Rubricguru. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $7.49. You're not tied to anything after your purchase.
