Respiratory System Flashcards
What is tidal volume?
The amount of air moved during quiet breathing
What is the thickness of the respiratory membrane?
0.5 micrometers
What are the requirements for the respiratory membrane?
- thin
- moist
- large blood supply
- large surface area
How many pulmonary lobes are in the right lung?
3
How many pulmonary lobes are in the left lung?
2
What are the functions of the respiratory system?
- moves air in and out of the body for O2 and CO2 exchange
- olfaction
- non-specific defence against pathogens
- acid-base balance
- vocal communication
What is the conducting zone?
Conducts air to the respiratory zone
What is the respiratory zone?
The area in which gas exchange occurs
What are the three types of cells in the alveoli?
- type 1
- type 2
- alveolar macrophages
What do type 1 alveolar cells do?
- simple squamous epithelium
- has exchange
What do type 2 alveolar cells do?
- maintain type 1 cells
- produce surfactant that prevents the alveoli from collapsing when we exhale
What do alveolar macrophages do?
- digest pathogens that reach the alveoli
- once they reach capacity they move up the conducting zone and get trapped in the mucociliary escalator
What makes up the blood/gas barrier?
- simple squamous epithelium of the type 1 alveolar cells
- simple squamous epithelium of the endothelial cells
- shared basement membrane
What are some characteristics of the blood/gas barrier?
- one of the thinnest surfaces in the body
- basement membrane contains collagen
What is Boyle’s law?
At a constant temperature, the pressure of a given quantity of gas is inversely proportional to its volume
What is Charles’s law?
At a constant pressure, the volume of a gas is directly proportional to its absolute temperature
How does the nasal cavity modify air entering the lungs?
- cleans
- moistens
- warms
Nasal cavity: cleans
Entry: hairs
Within: coli and mucus
Nasal cavity: moistens
Glands and goblet cells
Transduction
Nasal cavity: warms
Blood sinusoids: blood vessels that occupy the CT of underlying epithelium
Embryological development
Derived from ectoderm
By 8 weeks resemble an adult structure
What are the sections of the pharynx?
Nasopharynx, oropharynx and larygopharynx
Nasopharynx epithelium
Respiratory epithelium
Larygopharynx epithelium
Non keratinised stratified squamous epithelium
What is the primary function of the larynx?
Protection of the airway
Secondary: phonation
What does the epiglottis do?
When swallowing bends backwards and covers the larynx
What type of cartilage is around the trachea?
Hyalin
Why are there gaps in the cartilage?
Allows room for esophagus to expand when food is swallowed
How does smoking affect the respiratory system?
- causes paralysis of cilia function
- overtime causes metaplasia - changes to stratified squamous epithelium
Main bronchi
Go into each of the lungs
Lobal bronchi
Go into each of the lobes
Segmental bronchi
Go into bronchopulmonary segments
Bronchi epithelium/cartilage/muscle
- cartilage
- pseudostratified columnar ciliated
Bronchioles epithelium/cartilage/muscle
- smooth muscle
- ciliated pseudostratified epithelium to simple ciliated columnar
What are terminal bronchioles?
- final branches of conducting zone
- ciliated columnar epithelium (no goblet cells)
Where do the lungs receive blood from?
- pulmonary arteries (98%)
- bronchial arteries (2%)
Do alveolar ducts have smooth muscle?
Yes
What stimulates the diaphragm?
Phrenic nerve
What does the diaphragm move?
Moves itself inferiority
Pushes outward on sternum and ribs
What is normal blood pH?
7.35-7.45
Explain why the interpleural pressure is negative
- due to their elasticity, at the end of normal expiration the chest wall with its pleura tends to expand outward whereas as the lungs with their pleura tend to recoil inwards
- as the chest wall and lungs are pulling in opposite direction, a slightly negative pressure is generated in the interpleural space
Explain how changes in the position of the diaphragm and chest diameter influence changes in volume and pressure that contribute to inflation of the lungs (refer to Boyle’s law)
- when the diaphragm contracts inferiority and the ribs move up and out during inspiration, the parietal pleura follows
- as the visceral layer clings to the parietal layer the lungs expand
- due to the increase in volume, the internal pressure of the lungs relative to the outside drops (Boyle’s law) and air flows in
Explain how the warming of the air inhaled by structures su h S the nasal conchae contributes to inflation of the lungs
- according to Charles’s law, the volume of a gas is directly proportional to its absolute temperature
- by the time air reaches the alveoli, it has been warmed to 37 degrees
- if the air outside is cooler than this, then the inhaled volume will increase due to thermal expansion, further contributing to lung expansion
What is the role of surfactant?
- for gas exchange to occur alveoli must stay moist
- this creates a problem as during exhalation the alveoli would stick together like pieces of wet paper making them difficult to rein flame
- surfactant coats the alveoli and smallest bronchioles to prevent them from collapsing during exhalation
Why does residual volume always occur?
Because the lungs are stuck to the chest wall via pleura
Where does gas exchange first occur?
Respiratory bronchiole
Where does smooth muscle disappear?
Alveolar duct
Where does simple squamous epithelium first appear?
Respiratory bronchiole
Where are is the ventral respiratory group?
- medulla oblongata
- contains I and E neurons
- E neurons cause the diaphragm to contract, I inhibit E neurons
How many times do you breath per minute?
12
Where are the peripheral chemo receptors?
Aortic and carotid bodies
What does the dorsal respiratory group alter?
Rat and depth of breathing
