3.1 - Exchange and Transport Flashcards
What substances need to be exchanged between an organism and their environment?
- Glucose - in
- Oxygen - in
- Urea - out
- Carbon dioxide - out
What makes an efficient exchange
Factors of an efficient exchange system?
- Large Surface Area
- Thin
- Good Blood Supply/Ventilation
Function of Goblet Cells and where are they found?
- Line airways
- Secrete mucus which traps microorganisms and dust particles which stops them from reaching alveoli
Function and location of Cilia
- Surface of cells lining airways
- Beat mucus which moves trapped microorganisms and dust away from the alveoli and towards the throat to be swallowed
- This prevents lung infections
Function and location of Elastic Fibres
- Walls of the trachea, bronchi, bronchioles and alveoli
- During inspiration, the lungs inflate and the elastic fibres are stretched
- During expiration, the elastic fibres recoil to help push the air out when exhaling
Function and location of Smooth Muscle
- Walls of the trachea, bronchi and bronchioles
- Allows their diameters to be controlled
- E.g. during exercise, smooth muscle relaxes which makes the tubes wider. This means there is less resistance to airflow and air can move in and out of the lungs more easily.
Function and location of Rings of Cartilage
- Walls of trachea and bronchi
- Provide structural support
- Strong but flexible
- Stops the trachea and bronchi collapsing during inspiration when the pressure drops
What is inspiration and expiration?
A form of ventilation in mammals that consists of breathing in and out
Outline inspiration
- External intercostal and diaphragm muscles contract
- Causes ribcage to move up and out and the diaphragm to flatten which increases the volume of the thorax
- As volume of thorax increases, lung pressure decreases to below atmospheric pressure
- Causes air to flow into the lungs
- Active process - requires energy
Outline expiration
- External intercostal and diaphragm muscles relax
- Ribcage moves down and in, the diaphragm becomes curved again
- Thorax volume decreases causing the air pressure to increase above atmospheric pressure
- Air is forced out of the lungs
- Passive process - no energy required
During forced expiration (e.g. blowing out candles) the intercostal muscles contract to pull the ribcage down and in
What is the tidal volume?
Volume of air in each breath (usually 0.4 dm3)
What is the vital capacity?
Max. volume of air that can be breathed in or out
What is the breathing rate?
How many breaths are taken per unit time (usually 1 min)
What is oxygen consumption/uptake?
Rate at which an organism uses up oxygen
(dm3 used per minute)
Sketch and label spirometer trace
What is a spirometer?
A machine that gives readings of:
- Tidal Volume
- Vital Capacity
- Breathing Rate
- Oxygen Uptake
What system do fish use for gas exchange?
Counter-Current System
How are fish gills ventilated?
- Fish opens its mouth which lowers the floor of the buccal cavity.
- The volume of the buccal cavity increases, decreasing the pressure inside the cavity, water is then sucked into the cavity.
- Fish closes its mouth, raising the floor of the buccal cavity again.
- The volume inside the cavity decreases and the pressure increases, water is forced out of the cavity across the gill filaments.
- Each gill covered by bony flap (operculum) which protects the gill. The increase in pressure causes the operculum on each side of the head to open, allowing water to leave the gills.
What is the counter-current system in fish gas exchange?
Outline gas exchange in fish
