Lecture 1 Flashcards
What are the Functions of the Respiratory System?
Gas exchange – Oxygen added to the blood from the air, carbon dioxide removed from the blood into the air.
Acid base balance – regulation of body pH (see renal lectures)
Protection from infection
Communication via speech
What are the 2 types of respiration and what do they do?
Cellular/Internal respiration – biochemical process that releases energy from glucose either via Glycolysis or Oxidative Phosphorylation. Latter requires oxygen and depends on:
External Respiration – movement of gases between the air and the body’s cells, via both the respiratory and cardiovascular systems
What is the difference between pulmonary and circulatory resp?
Pulmonary is heart to lungs and circ. is heart to tissues
What do the pulmonary vein and pulmonary artery carry?
Pulmonary vein = oxygenated blood back to heart from lungs,
Pulmonary artery = de-oxygenated blood from heart to lungs
Veins are returning (venous return). Arteries = Away from heart
Where do the 3 places of gas exchange occur?
I = Atmosphere and Lung II = Lung and blood III = blood and cells
What is the net volume of gas exchanged in the lungs per unit time in steady state?
250ml/min O2; 200ml/min CO2
What is resp rate at rest and what can this get up to in exercise?
12-18 at rest, 40-45 during exercise
Order the following nose -> lung
Larynx, Bronchus, Pharynx, Epiglottis, Trachea
Nose, Pharynx, Epiglottis, Larynx, Trachea, Bronchus, Lung
Never Pull Euan Looking To Break Legs
Name the components of the upper resp. tract
Larrynx and above (Nasal cavity, Tongue, Pharynx, Vocal Chords, Esophagus, Larrynx)
Name the components of the Lower resp. tract.
Trachea and below (Trachea, Lungs, Bronchus)
Which systems share the pharynx?
Digestive and Resp.
What does the epiglottis do?
Small flap of tissue that folding over the trachea and stopping food entering trachea when you swallow.
What does the larynx do?
Produces sound (contains vocal chords)
What is the trachea made of?
Stiff rings of cartilage
What defines the separation of the upper and lower respiratory systems?
Lower resp system is enclosed in thorax, bound by ribs, spine and diaphragm
What does the respiratory zone consist of?
Alveoli (site of gas exchange) and airways to which alveoli are attached
What does the conducting zone of the airways consists of
the trachea, bronchi (highest points of resistance to air flow), and bronchioles. Air in these airways is referred to as Anatomical Dead Space as it does not participate in gas exchange as the walls of the airways are too thick.
What is the major determinant of airway resistance?
radii and number of airways
What does airway resistant determine?
how much air flows into the lungs at any given pressure difference between atmosphere and alveoli
What is the volume of the lungs and the surface area of the alveoli?
The surface area of the alveoli is enormous (80m2) but extremely thin so fits in a volume of approx. 6 L (3 L in each lung)
What is the generic composition of air?
78% Nitrogen, 21% O2, 1% argon, co2 and others
What are the hairs on resp tract cells called?
Cilia
What happens to the trachea under the sternum angle and where is the sternum angle?
Trachea splits into 2 primary bronchi.
Sternum angle is 2/3 finger widths down from jugular notch
How many times do the bronchi continue to divide?
About 24
What is the digestive system also known as and what is the only part of the upper respiratory tract that isn’t shared with the digestive system?
Alimentary system. Larynx
What splits the superior and middle lobes of the right lung?
Horizontal fissure
What splits off the inferior lobe?
Oblique fissure
What cavity is the pleural cavity in?
Thoracic cavity
Where do the secondary bronchi go?
To each lobe of lung. Therefore there are 2 secondary bronchi on left lung and 3 secondary bronchi on the right
What do the tertiary bronchi form?
Each one goes to its own segment.
The lungs are split into lobes which are further divided into segments
What maintains patency (airway is open and air can flow freely) in airways?
Semi rigid Cartilaginous C shaped rings
What are bronchi once they have lost cartilaginous rings?
Bronchioles
How do bronchioles stay open?
Physical forces in thorax
How much air is sitting in our dead space at any one time? Where is this air?
~ 150ml. Air in “conducting zones” - trachea,bronchi and bronchioles.
Why are aspirated foreign bodies more likely to get stuck in the R bronchi compared to the left?
Because slightly wider and more vertical trajectory
Match the diameter(mm) to the branch:
Trachea Primary bronchi Smaller bronchi Bronchioles Alveoli
1-10 0.3 0.5-1 15-22 10-15
Trachea = 15-22mm Primary bronchi = 10-15mm Smaller bronchi = 1-10mm Bronchioles = 0.5-1mm Alveoli = 0.3
Where is the greatest resistance to airflow in the lungs and why?
Trachea- smaller bronchi.
Because even though they are wider, there is much less of them. (1 trachea, 10s of millions bronchioles).
Therefore cross sectional area if trachea is about 2.5cm, and bronchioles is 100-5000cm, with alveoli cross sectional area is greater than 1000000cm
Where is the greatest resistance to airflow in the lungs and why?
Trachea- smaller bronchi.
Because even though they are wider, there is much less of them. (1 trachea, 10s of millions bronchioles).
Therefore cross sectional area if trachea is about 2.5cm, and bronchioles is 100-5000cm, with alveoli cross sectional area is greater than 1000000cm
What receptors does the sympathetic nervous system act on and cause in the lungs?
Beta 2 receptors (because you have 2 lungs). When adrenalin or noradrenaline bind to beta 2 receptors in the lungs it brings about relaxation to the bronchioles smooth muscle, increasing diameter and reducing resistance in airways leading to more air in and out, as part of flight or flight
What do the elastic fibres surrounding the alveoli do?
They mean that we can have passive exhalation as they destretch
What do type I and type II cells do?
Type I = main type in alveolar wall. Gas exchange occurs across these cells
Type II = secrete surfactant. Not involved in gas exchange
One key immune cells in alveoli
Alveolar macrophages
