Exchange Surfaces Flashcards
(4 cards)
Mammalian gaseous exchange system
Mammalian gaseous exchange system
- Lungs located in the chest cavity surrounded by the rib cage. A lubricating substance is secreted to prevent friction between rib cage and lungs during inflation and deflation.
- External and internal intercostal muscles between the ribs which contract to raise and lower the ribcage
- Diaphragm separates lungs from abdomen area
Cartilage- involved in supporting the trachea and bronchi, preventing the lungs from collapsing during exhalation
Ciliated epithelium – present in bronchi, bronchioles and trachea, involved in
moving mucus along to prevent lung infection by moving it towards the throat
Goblet cells – cells present in the trachea, bronchi and bronchioles involved in mucus secretion to trap bacteria and dust to reduce the risk of infection with the help of lysozyme which digests bacteria
Smooth Muscle, contract to restrict air flow
Elastic fibres – stretch when we inhale and recoil when we exhale thus controlling
the flow of air
Ventilation
Ventilation (inspiration and expiration)
- Ventilation, flow of air in and out of the alveoli
Inspiration
- external intercostal muscles contract and internal costal muscles relax, causes rib to raise upwards
- diaphragm contracts and flattens
- In combination, this causes the volume inside the thorax to increase, thus lowering the pressure
- Difference between air pressure causes air to enter the lungs
Expiration
- internal costal muscles contract, external costal muscles relax, lowers rib cage, diaphragm relaxes and raises upwards
- In combination, decreases the volume in the thorax, increases air pressure, forces air out of lungs
Spirometer
- device used to measure lung volume
- person breaths in and out of air tight chamber, causes it to move up and down, leaving a trace on a graph
- Vital Capacity, maximum volume of air that can be inhaled or exhaled in a single breath, varies depending on age, gender, size, height.
- Tidal Volume, volume of air breathed in and out at each breath at rest
- Breathing Rate, number of breaths per minute (number of peaks or troughs per minute)
- Residual Volume, Volume of air that is always present in lungs
Ventilation and gas exchange in bony fish and insects
Ventilation and gas exchange in bony fish and insects
- each gill supported by an arch, each arch have gill filaments with lamellae on them
Ventilation and gas exchange in bony fish and insects
Ventilation and gas exchange in bony fish and insects
- each gill supported by an arch, each arch have gill filaments with lamellae on them
- Blood and water flow in opposite directions to maintain steep concentration gradient
- fish opens mouth lowering its buccal cavity, enabling water to flow in, fish closes mouth causing buccal cavity floor to rise, increases pressure, water is forced over gill filaments and through opercular cavity
Insects
- Spiracles, tubes supply insects with required gases
- these opening are trachea which split into smaller tracheoles
- tracheal fluid found at the end of each tracheole, allows gases to dissolve and then diffuse into cells
- Spiracles can be opened or closed to minimise water loss
