Respiratory Physiology Flashcards
Diffusion only works for ______ organisms. Give one metric which explains this
Small
The surface area to volume ratio gets much smaller as mass increases
List 5 strategies for gas exchange, and an example for each
1) Diffusion (water or air)– Bacteria
2) Bulk flow of water – Sponge
3) Bulk flow of air – Insect
4) Diffusion/gas transport– Leech/Earthworm
5) Ventilation/ gas transport– Vertebrate
How much oxygen does air have per volume compared to water? What does this mean?
1/30 as much oxygen
Need a higher flow rate of water!
What strategy do amphibians employ?
Diffusion/gas transport alone or in combination with ventilation/gas transport (skin, or both skin and lungs)
Name two amphibians
Frog and salamander
What happens when amphibians transition from tadpoles to frogs?
Go from using gills to lungs
Name and discuss three factors that affect the efficiency of gas exchange
1) Distance between blood flow and medium (thinner membrane= better!)
2) Tidal ventilation vs constant ventilation (tidal ventialtion= breathing, not as good as constant exposure)
3) Direction of flow countercurrent is more efficient than crosscurrent, which is more efficient than concurrent
How efficient is a countercurrent exchanger? How about a simple lung
80-90% efficient, vs. 20-25% efficient
What do underwater animals use for gas exchange with the environment?
Gills
Name four types of underwater creatures that have gills
Molluscs, Cephalopods (squids), Crustaceans (lobsters)
Name one creature that maintains embryonic external gills
Axolotl
What kind of pump do sharks use to ventilate gills (what body part does it use also)?
Buccal Pump (Mouth)
Name two factors that increase the efficiency of fish gills at oxygen extraction. Name two key parts
Buccal-Opercular Pump
Countercurrent Flow in gills
Primary lamella, secondary lamella
How frequently do fish breathe compared to humans?
Five times more often!
What openings facilitate bulk flow of air in insects? Can they be opened and closed?
Spiracles
Yes
What openings does a spider have? What kind of a lung does the spider have? What is special about this lung? What is one internal part of this lung?
Spiracles
Book lung
It increases surface area!
Lamallae
What kind of a mechanism do reptiles use to ventilate their lungs? Describe.
Suction-pump mechanisms. Movements of abdominal muscles and limbs open and close the lungs
Bird lungs are very ________ and can extract a ______ percentage of oxygen from the air. They use ________ ventilation, and have both _______ and lungs ___________.
Efficient high continuous air sacs lungs
List the parts of the air pathway from mouth to the end
Mouth/nostril, pharynx, larynx, trachea, primary bronchi, secondary bronchi, tertiary bronchi, bronchioles, terminal bronchioles
What fills most of the chest cavity?
the lungs
Where is the trachea located? What is it made of? How many rings? what is on the side facing the esophagus?
In front of the esophagus
Hyaline cartilage
16 to 20 incomplete rings
Smooth muscle
What lines the inside of the trachea? What do we call the smooth muscle at the back of the trachia?
respiratory epithelium
Trachealis muscle
What does the respiratory epithelium do? Why?
Produces and transports mucus. To capture foreign particles and pathogens
Where do we find the respiratory epithelium? What does it have, what do they do, and in what direction?
In nose, trachea and bronchi. Cilia in nose beat down toward pharynx. Cilia and trachea and bronchi beat upwards toward mouth. They can move particles at 1-2 cm per minute!
What is one disorder of the epithelial cells in the lungs? Describe it in detail
Cystic Fibrosis: If there is a mutation in the CFTR, then Cl transport across the membrane is defective, and as a result, water transport is defective as well. The mucus produced by the epithelial cells has less water, so it is thick and sticky and obstructs the airways.
What landmark surgery occured in 2011? What was the object made of?
First synthetic trachea transplant. Articial windpipe made of porous glass and stem cells
What are the three layers that cover the lung, from inside to out. What is their function?
Visceral pleura, pleural cavity filled with intrapleural fluid, parietal pleura.
Protection!
State Boyle’s Law. Why is it important for the lungs?
P1V1= P2V2. So that when we expand the chest cavity, the lungs fill with air, and vice versa
What happens if we puncture the chest cavity? (official term and description)
Pneumothorax. Now, instead of being at greater than atmospheric pressure, the pressure in the lung equilibriates with atmospheric pressure, and the lung collapses!
What are the structures in the conducting zone?
Trachea, bronchi, bronchioles, terminal bronchioles
What are tthe structures in the respiratory zone?
Respiratory bronchioles, alveolar ducts, alveolar sacs
What is the surface are of the lung equal to?
A tennis court (760 sq. feet)
How many alveolar sacs are there?
8*10^6
What surrounds the alveolar sacs?
Capillaries
How thick is the epithelial cell wall of the alveolar sacs?
One cell thick!
Discuss gas transport as we go deeper and deeper into the lung
Convection and bulk air flow through the bronchiles, then diffusion through the alveoli
What is another disease of the lung? How does it work?
Asthma. Bronchioles constrict due to smooth muscle, and may also have inflamed/enlarged linging. Makes it difficult for air to travel to alveoli!
How thick is the alveolo-capillary membrane?
0.5 micrometer
Name the four layers of the alveolo-capillary membrane (from gas to blood)
Surface film, alveolar epithelium, interstitial space, capillary endothelium
Name the three cell types of the Alveoli (along with description)
1) Type I alveolar cells- 97% of total, where gas exchange occurs!
2) Type II alveolar cells- secrete SURFACTANT
3) Alveolar duct cells- wandering macrophages that remove debris
What is surfactant composed of? What is its function? When does it start being made?
- Detergent-like substance- consists of DPPC, phospholipids (mostly), lipproteins
- A thin layer of alveoli causes surface tension that collapses the alveoli when people exhale. The surfactant decreases the surface tension and stops the alveoli from collapsing.
- Surfactant is produced late in fetal life, so it can be an issue if born too early!
What law governs the collapse of alveoli? What is the effect that surfactant has specifically? Give the equation
Law of Laplace: Air from smaller ones flows into larger ones if surface tension is too high, collapsing smaller ones.
P=2T/r
______________ is the _____ cause of death in _______ infants. Due to a _________ and ______ collapse
Neonatal Respiratory Distress Syndrome
leading, premature
lack of surfactant, alveoli collapse
What do we use to counter Neonatal Respiratory Distress Syndrome?
synthetic surfactant, ventilator
Name two synthetic surfactants
Exosurf
Alveofact (cow lung, also use pig lung)
What lung condition results from smoking? Describe it
Emphysema (“smoker’s lung”)- alveoli start breaking up and collapsing, creating large open pockets. This reduces surface area, and reduces gas exchange!
What was the first working replacement lung implanted in?
a Rat
What determines airflow into and out of lungs?
Pressure differences: air moves into lungs when pressure inside is less than atmospheric pressure. Air moves out when pressure inside is greater than atmospheric pressure.