Unit 5; Respiratory System Flashcards
What are the 4 functions of the respiratory system
- exchange of gases between atmosphere and blood
- homeostatic regulation of body pH
- protection from inhaled pathogens and irritating substances
- vocalization
What is the first exchange in the respiratory system
gas exchange between atmosphere and lungs
What is the second exchange in the respiratory system
gas exchange between lungs and blood
What occurs between exchange 2 and 3
transport of gases by blood
What is the third exchange in the respiratory system
exchange of gases between blood and tissues
What is another term for the transport of gases between atmosphere and lungs
ventilation
What is it called when air moves into lungs
inspiration or inhalation
What is it called when air moves out of the lungs
expiration or exhalation
What is the conducting system of the respiratory system
airways
What is the exchange surface of the respiratory system
alveoli
What is the pumping system of the respiratory system
bones and muscle of thorax
What are the components of the upper respiratory system
mouth, nasal cavity, pharynx, larynx
(above trachea)
What are the components of the lower respiratory system
trachea, bronchi, bronchioles, lungs
(below trachea and at lungs)
What are alveoli
tiny sacs found at the ends of terminal bronchioles wrapped in capillary network - gas exchange occurs between alveoli and capillaries
Why does gas exchange occur specifically at the alveoli
small surface area and connected to huge capillary network - allows for efficient diffusion
What are the two types of alveolar cells
type 1 and type 2
What are type 1 alveolar cells
large but thin
- allow for rapid gas diffusion (thin layer = faster diffusion)
What are type 2 alveolar cells
small but thick
- synthesize and secrete surfactant
Where does low oxygen blood exit the heart
right ventricle
Where does low oxygen blood travel once it has left the right ventricle
pulmonary arteries via the pulmonary trunk
Why is the rate of blood flow high in pulmonary circulation
all blood leaving the heart goes to the same place: the lungs
Why is the rate of blood flow lower in systemic circulation
the blood leaving the heart flows all around the body, not all to the same place (unlike exchange 2)
Why is blood pressure low in pulmonary circulation
right ventricle doesn’t have to contract as hard since its only sending blood to one place
Why is blood pressure higher in systemic circulation
left ventricle has to contract harder since it is pushing blood around the body, and not just to one location
Which ventricle pumps more forcefully in the heart
the left ventricle (systemic circulation)
What is another term for the chest
the thorax
What makes the thorax (chest) a closed compartment
- closed off at top by neck muscles and connective tissues
- closed off at bottom by the diaphragm
What is the wall of the thorax formed by
ribs and intercostal muscles
(costal=ribs, therefore intercostal muscles are literally just muscles at the ribs)
What are the neck muscles involved in the closed compartment of the thorax
sternocleidomastoids and the scalenes
What happens when the intercostal muscles contract
inspiration
What happens when the intercostal muscles relax
passive expiration
What muscles are required for active expiration
internal intercostals and the diaphragm
What shape is the diaphragm when relaxed
dome
What shape is the diaphragm when contracted
flat
When does the volume of the thorax increase
when the diaphragm contracts and flattens (inhalation)
When does the volume of the thorax decrease
when the diaphragm relaxes and expands (exhalation)
What surrounds the lungs
pleural sac
What is found within the pleural sac, and what is its purpose
pleural fluid; acts as a lubricant
What is the equation for total gas pressure
total pressure = sum of partial pressures
Gas moves from areas of _____ pressure to ______ pressure
high to low
What two factors determines if a gas will dissolve in a liquid
- partial pressure of the gas
- solubility of the gas in liquid
What is the law applied to pressure-volume relationships
Boyle’s law
What is the driving force of airflow
changes in alveolar pressure
Can the lungs change volume on their own?
no!
What does lung volume depend on
- transpulmonary pressure
- degree of elasticity of the lungs
Pressure inside of the lungs is known as ___________ pressure
alveolar
Pressure outside the lungs is known as pressure in the ___________ _________
intrapleural fluid
Difference between the alveolar pressure and the pressure of the intrapleural fluid is known as…
transpulmonary pressure
What is bulk airflow
flow of air between atmosphere and lungs
In what 3 ways do the airways condition the air before it reaches the lungs
- warm to 37 degrees
- add water vapour
- filter out foreign material
What are airways lined with
ciliated epithelia
What do ciliated epithelia secrete
watery saline solution
How do the ciliated epithelia secrete watery saline solution
cells move Cl from ECF into the lumen of the cell (via apical ion channel)
Na moves between cells from ECF to the lumen, and the concentration gradient of NaCl draws water towards the lumen creating a watery saline solution
Cilia are covered with _________
mucus
What cells secrete mucus
goblet cells
What is the mucus escalator
when mucus moves up the pharynx and transfers to the digestive tract where bacteria is destroyed
What disease results from a mutation in the Cl channel
cystic fibrosis
What is the result of the defective Cl channel in cystic fibrosis
insufficient secretion of the watery saline = thick and sticky mucus
What is the subsequent concern with cystic fibrosis
the thick and sticky mucus restrains the cilia, which doesn’t allow for proper movement or removal of bacteria = repeated infections (leads to overactive immune cells)
What does the somatic neuron trigger
contraction of diaphragm and inspiratory muscles - leads to inspiration
During inspiration, thoracic volume ___________ and alveolar pressure ___________
increases, decreases
When impulses from somatic motor neuron stop, what happens
diaphragm and thoracic muscles relax = expiration
During expiration, thoracic volume ____________ and alveolar pressure ______________
decreases, increases
What is elastic recoil
when exhalation occurs, thoracic volume decreases which causes recoil of the lungs and lung volume subsequently decreases
Passive expiration depends entirely on ____________ _________
elastic recoil
Active expiration depends on contraction of __________ ________________ and _________ muscles
internal intercostals and abdominal muscles