Exchange and Transport in Animals (not heart or O2/CO2 transport) Flashcards
What does ventilation do?
Maintains the concentration gradient necessary for passive diffusion.
Adaptations of trachea- 2
incomplete C-shaped rings of strong and flexible hyaline cartilage
Smooth muscle contracts for forced exhalation
Adaptations of Nasal cavity - 3
Large surface area and good blood supply.
Goblet cells secrete mucus
Moist surfaces (due to mucus)
Adaptations of bronchi- 3
Cartilage supports shape
smooth muscle helps control diameter
nerves of parasympathetic (slows down) and sympathetic (speeds up) nervous systems control muscle relaxation and contraction
Adaptations of bronchioles- 2
smooth muscle controls diameter
lined with cilia and goblet cells
Adaptations of alveoli- 6
Very flattened epithelial layer - 1 cell thick
Good blood supply
Collagen to strengthen
Elastin for recoil
Huge numbers to maximise SA
Covered with layer of fluid to dissolve gases
Surfactant
Prevents collapse and allows inflation, ensures balanced surface tension.
Role of smooth muscle in asthma
and asthma treatments- 2
Cells lining bronchioles release histamines (chemicals make epithelial cells inflamed and swollen), stimulating goblet cells to make excess mucus and smooth muscle in bronchiole walls to contract. - airways narrow and fill with mucus.
Relievers- chemicals attach to active sites of surface membrane of smooth muscle cells in bronchioles, making them relax and dilate airways.
Preventers- (often steroids) taken everyday reduce sensitivity of airway linings
What does ventilation do?
Maintains the concentration gradient in alveoli necessary for passive diffusion by constantly cycling fresh air. O2 levels high and CO2 levels low in alveoli.
Three ways we can measure ventilation.
Observation/ counting breaths per minute
Chest belt and pressure meter
Spirometer
Are inspiration and expiration active or passive processes?
Inspiration = active Expiration= considered passive
Inspiration: External intercostal muscles Internal intercostal muscles Diaphragm Air pressure in lungs Air movement(along pressure gradient) Lung volume
External intercostal muscles: contract, pulling ribs UPWARDS and OUTWARDS
Internal intercostal muscles: relaxed
Diaphragm: muscles contact, causing diaphragm to flatten
Air pressure in lungs: decreases
Air movement(along pressure gradient): air moves into lungs
Lung volume: increases
Expiration: External intercostal muscles Internal intercostal muscles Diaphragm Air pressure in lungs Air movement(along pressure gradient) Lung volume
External intercostal muscles: relax
Internal intercostal muscles: contract, pulling ribs INWARDS and DOWNWARDS
Diaphragm: muscles relax, causing diaphragm to curve upwards
Air pressure in lungs: increases
Air movement(along pressure gradient): air moves out of lungs
Lung volume: decreases
What happens during forced exhalation?
Internal intercostal muscles contract and abdominal muscles contract, pushing diaphragm upwards.
What feature of tissues also aids expiration?
Elastic recoil of tissues (bronchi/bronchioles) aids expiration.
What causes ventilation? (not muscles)
pressure gradient
Ventilation equation with units
pulmonary ventilation (dm3min-1) = tidal volume (dm3) x ventilation rate (min-1)
Considerations when using a spirometer
- Closed system- created by water
- Use of a nosepiece
- Patient health
- Sodalime absorbs CO2 (will cause trace to go down)
- Counterbalance removes resistance for breathing
Which part of a spirometer is mobile?
The upper half which is full of oxygen.
What is the lower half of a spirometer tank full of?
Water
Will the trace on a spirometer rise or fall when the patient breathes in?
fall
What is vital capacity?
Volume of air that can be exchanged via the lungs via a maximal inhalation and exhalation.
What is residual volume?
Volume of air that is always present in the lungs.
What is tidal volume?
Volume of air that is exchanged via normal breathing. (one breath)