Respiratory Structure and Function: Lecture 2 & 3 Flashcards
What is the MAIN purpose of the respiratory system?
to get oxygen into the body for the cells and to get rid of carbon dioxide that the cells of the body produce
What are the 2 separate processes of the respiratory system?
- Internal respiration
- External respiration
What is the difference between internal and external respiration?
External = all of the movement of oxygen and carbon dioxide outside of the cells
Internal = everything that happens in the cell
What is External Respiration?
all the events that are involved in the exchange of O2 and CO2 between the external environment and the cells of the body
How many steps are there for external respiration?
4
What are the 4 steps of external respiration?
- Ventilation
- Diffusion (i)
- Blood transport
- Diffusion (ii)
“at the level of the tissue”
What is happening at ventilation?
movement or air into and out of the lungs
What is happening at diffusion (i)?
O2 and CO2 are exchanged between the air in alveoli within the pulmonary capillaries via diffusion
What is happening at blood transport?
O2 and CO2 are being transported to the lungs and tissues
What is happening at diffusion (ii)?
at the organ or tissue…
O2 and CO2 are being diffused between the tissue and the blood across systemic capillaries (tissues)
blood —– tissue—- diffused into cell
True or False
Oxygen and Carbon dioxide are completing these steps in opposite orders
True
When we breathe in what is the fraction of the oxygen we breathe in from the air?
20.93% - 21% percent oxygen
When we breathe in what is the fraction of the carbon dioxide we breathe in from the air?
0.03% - basically nothing
What is the concentration of oxygen at the end of a breath?
lower than 21%. Approx 16%
What is the concentration of carbon dioxide at the end of a breath?
higher than 0.03%. 4 -5%
Veins carry what?
deoxygenated blood, carbon dioxide rich blood
Arteries carry what?
oxygenated blood, carbon dioxide poor blood
What is the Wasserman Gears of Life?
“gears” that explain the external respiratory system
- oxygen is inspired
- is diffused by pulmonary circulation
- oxygen is sent to peripheral circulation
- is diffused into the muscles
- oxygen is consumed by mitochondria
- carbon dioxide goes through the same system backward
What are the nonrespiratory functions of the respiratory system?
- water
- heat loss
- enhances veinous return
- speech
- singing
How does the respiratory system enhance veinous return?
due to the fluxations of pressure in the chest wall, where the heart is enclosed
What are the 3 general pieces of anatomy in the respiratory system?
Airways leading into the lungs
- bronchi
Lungs
- airways
- alveoli
- all these elastic structures
Thorax
What are the pathways of oxygen going from the atmosphere into the lungs?
- nasal passage / oral passage
- larynx goes down
- trachea
- right and left bronchi
- right and left bronchioles
- terminal bronchiles
- alveolar sacs
- alveolus
What is the start of the conduction zone called?
trachea
How many times does the bronchus split through bronchioles to alveoli?
23 times
is there any gas exchange in the conducting zone?
NAUR
Where does gas exchange occur mainly?
Alveoli, alveolus
True or False
The pressure at the alveolus level is very low due to the huge amount of cross-sectional area
True, for us to have a gas exchange
From the bronchi to the terminal bronchioles and the alveoli, there are cilia. What is its purpose?
to help protect against foreign things, aka coughing will occur
Why do we secret mucus in the lungs?
- to keep moist and lubricated
- it can represent inflammatory responses
- kids with CF
Where is the end of the conduction zone?
terminal bronchioles
What dictates the respiratory zone?
alveolus, alveolar sacs
Why are the small airways in the respiratory system covered in smooth muscle?
aka terminal brochioles
this can change the diameter of the tube
Where are the Pores of Kohn?
within the alveolar sacs
What do the Pores of Kohn do?
- allows for alveolar communication
- ensuring each alveolus is properly inflated, “pressure needs to be the same”
surfactant does what?
regulates breathing pressures, and keeps the alveolus from collapsing
True or False
Capillaries completely engulf each alveolus
True
How many alveolus are there?
approx 3 million
How many capillaries are there?
6 million
Where are the lungs located?
thoracic cavity
What is dictated as the thoracic cavity?
bottom of the lungs to the top of the collarbone
What is the thoracic cavity? Definition
air-tight sealed space, shared with heart and blood vessels
What is in the lower part of the thoracic cavity?
diaphragm
What are some key features that are kept in the lungs?
- highly branched airways
- alveoli
- pulmonary blood vessels
- large quantities of elastic connective tissue
What do the large quantities of elastic connective tissue help us with?
- managing the size of our chest
- the volume of air in
- ease of breathing
True or False
The elastic connective tissue allows us not to use our muscles to breathe out
True, due to the elastic properties of the lung
What is the nasal passage?
nose
What is the pharynx?
splits up respiratory from digestive
What is the larynx?
voice box
What is the trachea?
windpipe
- rigid, nonmuscular tubes
- rings of cartilage preventing collapse
What do bronchioles contain?
- walls that contain smooth muscle innervated by the autonomic nervous system
- sensitive to certain hormones and local chemicals
- no cartilage to hold them open
What is found at the end of the bronchioles?
alveoli (air sacs) clustered at the ends of the terminal bronchioles
Why do the bronchioles have smooth muscles?
for constriction and dilation controlled by the autonomic nervous system
What do “puffers” do?
bronchial-dilator: relax smooth muscle to open up the airways
- targets the smaller areas of the bronchioles
What are the alveoli?
thin-walled, inflatable sacs that function in gas exchange
What do the walls of Alevoli consist of?
a single layer of flattened Type 1 alveolar cell
What do Type 2 alveolar cells do?
make pulmonary surfactant
Where are type 2 alveolar cells located?
in the lumen of the alveolus
After how many weeks approximately will infants create surfactant on their own?
34-35 weeks
What does surfactant do?
decrease the surface tension on the Type 1 walls of the alveolus
What do Alveolar macrophages do?
Guard lumen
- the individual alveolus
What do Pores of Khon do?
allow for airflow between adjacent alveoli
aka collateral ventilation, communication between cells
What is the approximate diameter of an alveolus?
300 micrometers
Why does the Type 1 alveolar cell need to be thin?
to maximize gas echange
The distance between the alveolar wall and the pulmonary capillary is what?
0.5 micrometres
What is the distance between the alveolar wall and the pulmonary capillary called?
interstitial space
When would the interstitial space be larger than normal or compromised?
pulmonary edema
What is high-altitude pulmonary edema?
the high altitude pressure will cause a leakage of the capillary network into the interstitial space causing it to expand
True or False
Cystic fibrous and Pulmonary embolism leads to fluid accumulation in the interstitial space
True
The chest wall is composed of what?
- ribs
- diaphragm
What is the most important thing about the chest wall other than protection?
It has muscles involved that generate pressure that causes airflow
People with lung disease will overuse which muscle?
sternocleidomastoid
What are the 5 key muscles for INSPIRATION?
- diaphragm (MAIN ONE)
- sternocleidomastoidd
- scalenes
- external intercostal (lines go towards sternum)
- parasternal intercostals
What are the 5 key muscles for EXPIRATION?
- Internal intercostals (facing away from the sternum)
- external abdominal oblique
- internal abdominal oblique
- transversus abdominis
- rectus abdominis
True or False
The muscles for inspiration are the same as the muscles we use to hold our breath in?
True
True or False
When we relax the muscle of inspiration our lungs will naturally deflate
True
True or False
Resting expiration is generally passive
True
If we need to cough, exercise, sing, or breathe out anything faster than the natural resting lung rate then we use which muscles?
expiration muscles
At rest, during passive/resting exhalation which expiratory muscles are recruited?
none of the above!! always during passive/resting
The diagram accounts for what percent of the enlargement of the thoracic cavity during quiet respiration?
75%, due to the contraction and flattening of the diaphragm
The onset of expiration begins at what?
the relaxation of inspiratory muscles
When we open up the lungs via the ribs and the diaphragm, what happens to the pressure inside the lungs?
- decreasing pressure in the lungs
- lower than atmospheric, allowing air in
- Boyles law
True or False
By increasing the volume we can decrease the pressure
True
What is the pleura?
the double-walled, closed sac that separates each lung from the thoracic walls/chest wall
The pleura attached to the outer surface of the lung is called what?
*Attached to the actual organ
visceral pleura
The pleura attached to the chest wall (the thoracic wall and the diaphragm) is called what?
Parietal pleura
The pleural sac is comprised of what 3 things?
- visceral pleura
- partial pleura
- fluid in between the two
What is the intrapleural pressure?
pressure in the pleural sac
