Lungs: anatomy, ventilation and gases Flashcards
The lungs are two cone shaped organs separated by the heart. Name the 4 surfaces of the lung:
- Apex (extends above clavicle)
- Base (over diaphragm)
- Costal (rib) surface
- Medial surface
From what artery is blood supplied to the lungs?
Pulmonary artery
How many lobes are there in the right and left lungs?
Left lung has 2 lobes (due to the heart)
Right lung has 3 lobes
What are pleura?
Pleura are serous membranes that surround the lungs.
Name the two layers of the pleura and the cavity between.
visceral layer, parietal layer and pleural cavity.
The visceral and parietal pleura form a double layer separated by 5-10ml of serous fluid, what does the fluid do?
Prevent friction
What is ventilation the process of?
Ventilation is the process through which O2 and CO2 are transported to and from the lungs.
Name the two main phases of ventilation…
- Inhalation
2. Exhalation
Breathing can come from which two areas?
- Abdominal (diaphragmatic) breathing (where most breathing should come from)
- Upper rib breathing
Name the two Primary ventilation muscles.
- Intercostal muscles
2. Diaphragm
Give examples of secondary ventilation muscles…
Trapezius, sternocleidomastoid and the scalenes.
The average pair of human lungs can hold about six litres of air.
What does the term ‘tidal volume’ represent?
The normal volume of air that enters the lungs during inspiration when no extra effort is applied.
(a normal tidal volume is 500ml)
Inspired air of gases:
Oxygen: 21%
Carbon Dioxide: 0.04%
Nitrogen and rare gases: 78%
Give the percentages of expired air per gas.
Oxygen: 16%
Carbon Dioxide 4%
Nitrogen and rare gases: 78%
Fill in the missing word:
98.5% of oxygen in the blood is transported by ______ in red blood cells.
Haemoglobin (Hb)
What do the terms ‘Oxyhaemoglobin’ and ‘Deoxyhaemoglobin’ mean?
Oxyhaemoglobin is when plenty of oxygen inbound to haemoglobin.
Deoxyhaemoglobin is haemoglobin that lacks oxygen.
Why is oxygen an essential gas in the body?
Because cells use oxygen to create the energy that is required for various processes.
What percentage of oxygen is dissolved in plasma?
1.5% of oxygen is dissolved in plasma
Carbon dioxide diffuses into the blood from respiring cells easily. It is transported in the following 3 ways:
- 70% found in plasma as HCO3- ( Bicarbonate)
- 23% carried in red blood cells (bound to haemoglobin)
- 7% dissolved in plasma (the water component of blood)
Bicarbonate buffer reaction.
What does that mean?
Bicarbonate is alkaline, which buffers the acidity of blood to keep pH stable.
Fill in the missing words:
CO2 diffuses down its concentration gradient from ____ into the ____.
tissues
blood
Fill in the missing word:
Because of the high water content of blood, CO2 combines with water to produce _____.
(also name the chemical formula)
Carbonic acid
H2CO3
As carbonic acid is unstable, it decomposes immediately into _______ and ___.
Bicarbonate and H+ (hydrogen ion)
pH is the measure of acidity, alkalinity and neutrality.
Blood pH needs to be controlled within very narrow limits.
What does Low pH =
What does High pH =
Low pH = elevated H+ ion concentration > more acidic
High pH = more alkaline
How does ventilation help to lower the acidity of body fluids?
Because ventilation means the exhalation of CO2. (Carbon dioxide)
