Week 1 - Intro, Histology, Upper Tract Flashcards
Define inspiratory reserve volume
Extra volume that can be breathed in over the tidal volume at rest
Define expiratory reserve volume
Extra volume that can be breathed out over the tidal volume at rest
What is the atmospheric pressure?
101 kPa
How can you use partial pressure to determine the volume of a gas?
The partial pressure of a gas is proportional to the percentage volume of that gas in the mixture
How can you use the pressure of a gas to determine its volume?
The pressure of a gas is inversely proportional to its volume
Explain Boyles law
If temperature is constant, pressure is inversely proportional to volume
- when your lungs expand in inspiration, the volume of air inside the lungs will increase so the pressure inside the lungs will fall. The pressure will fall below atmospheric pressure so air will flow into the lungs from the atmosphere
- when your lungs expand in expiration the volume of air in the the lungs decreases so the pressure rises above atmospheric pressure, hence air flows out of the lungs
How can you use the absolute temperature to determine the pressure of a gas?
If the amount and volume of a gas stays the same, then the pressure is directly proportional to the absolute temperature
- Kinetic energy increases with temperature so molecules will hit the walls more often, hence increasing the pressure
What is ‘vapour pressure’?
The pressure exerted when water molecules enter the gas phase
- On biological systems gas mixtures are always in contact with water
- Gas molecules dissolve and water molecules evaporate, exerting their own partial pressure – vapour pressure
What is ‘saturated vapour pressure’?
The pressure exerted by gas that is saturated by water (it is saturated when the water molecules enter and leave at the same rate - in equilibrium)
- depends on temperature
What is partial pressure in liquids?
Indicates pressure exerted by the dissolved gases in the liquids
- amount of dissolved gas = solubility X tension
- If the gas reacts with a component of the liquid, this reaction must take place before tension and content can be determined
- – Total content = dissolved gas + reacted gas
How is oxygen transported in the blood?
- Bound to haemoglobin
- dissolved in plasma (small amount)
How are the alveoli supplied with blood?
They are surrounded by pulmonary capillaries
- the blood vessels in the pulmonary circulation branch to form a tree like the airways
Describe ‘the bends’ (decompression sickness in divers)
Pressure increases dramatically with depth in water
- as you dive deeper, nitrogen moves from the lungs (high pressure) into the blood (low pressure)
- Swimming up to the surface too quickly doesn’t give the nitrogen enough time to leave the blood (can form painful bubbles)
- A slow return to the surface lets the nitrogen return to the lungs where it is breathed out
Define tidal volume
Volume in and out with each breath during quiet respiration
What is the upper respiratory tract?
The parts of the respiratory system lying outside of the thorax Includes: - Larynx - Pharynx - Nose
What are the functions of the upper respiratory tract?
- Conducting air from atmosphere to lower respiratory tract
- Conditioning (warming, humidifying, trapping particles) inspired air
- Protection of the airway during swallowing
- Smell
- Swallowing
- Speech
What is the lower respiratory tract?
The parts of the respiratory system lying inside the thorax Includes: - Trachea - Main bronchi - Lobar bronchi - Segmental bronchi - Sub-segmental bronchi - Bronchioles - Terminal bronchioles - Alveolar ducts - Alveoli
Describe the structure of the nasal cavity
- Divided into 2 cavities by the nasal septum (made of cartilage and bone and runs in the midline)
- Lateral wall of the nasal cavity has 3 bony projections which are known as conchae
- There are superior, middle and inferior conchae
- The conchae slow the airflow, helping to mix the air
- The space underneath a concha is called a meatus
- Lined by pseudostratified ciliated epithelia
What is the nasal cavity?
A part of the nose (other part is the external nose)
What are the functions of the nose?
- Filter air (nostril hairs filter large particles, mucus traps particles which are then wafted by the cilia)
- Smell
- Warm and humidify the air (vessels just below the epithelium warm the air, watery nasal secretions humidify the air)
- Receives local secretions (sinuses, nasolacrimal duct)
What are the paranasal sinuses?
Air-filled cavities in the skull which open into the nasal cavity
- Lined by respiratory epithelium
- Named for the skull bones within which they are located
- 4: frontal, ethmoidal, maxillary, sphenoidal