Exchange surfaces Flashcards
Vital capacity (2)
- Maximum volume of air inhaled/ exhaled in one breath
- tidal volume + IRV + ERV
Residual volume
- amount of gas remaining in lungs after expiration
- 20% of lung capacity
Tidal volume
- amount of gas inspired and expired during normal breathing
- 7-8% of TLC
Inspiratory reserve volume
Gas inhaled above tidal inspiration (above normal breathing)
60% TLC
Expiration reserve volume
Exhaled beyond tidal capacity
Equation for VC
- TV + IRV + ERV
Features of the Trachea (6)
Hyaline cartilage (incomplete, c-shaped rings)
Smooth muscle
Elastic fibres
Cliated epithelium
Goblet cells
Mucous glands
Features of alveoli (5)
Elastic fibres
Provides larger surface area
Thin layer of squamous epithelium allows quick diffusion
Network of capillaries for good blood supply and maintains steep conc.grad
Lung surfactant to maintain inflation at inner surface and elasticity.
Features of the larger bronchioles (4)
Smooth muscle: constriction
Elastic fibres
Ciliated epithelium
Goblet cells
What parts of the lungs contain cartilage (2)
Trachea
Bronchi
Features of bronchi (6)
Cartilage
Smooth muscle
Elastic fibres
Ciliated epithelium
Goblet cells
Mucous glands
Features of smaller Bronchioles (2)
- smooth muscle
- elastic fibres
Lung features with smooth muscle (4)
Teaches
Bronchi
Larger bronchioles
Smaller bronchioles
Features of smallest bronchioles
Elastic fibres
What structures contain elastic fibres
All of them
Name all 6
Describe function of cartilage (5)
- connective tissue
- supports and gives strength to trachea and bronchi
- flexible
- resistant tension and compression
- Holds airway open
What structures contain mucous glands (2)
Trachea
bronchi
What structures contain goblet cells (3)
Trachea
Bronchi
Larger bronchioles
Role of ciliated epithelium in lungs (3)
Secrets mucus via goblet cells to trap dust and bacteria
This moved to top of oesophagus by beating of cilia
Sealed by digestive tract to be disposed
Structures that contain ciliated epithelium (3)
Trachea
Bronchi
Larger bronchioles
Role of goblet cells in lungs
Produces mucus at surface of; Trachea, Bronchi and larger bronchioles
Mucus traps foreign particles like pathogens and dust.
Function of smooth muscles (4)
Found in; Trachea, Bronchi and lager bronchioles
Allow expansion for extra oxygen
Contracts to constrict the airways
Function of elastic fibres (3)
In all lung tissue
Provides elasticity for ‘elastic recoil’ in passive expiration
Helps to expel air
Function of the trachea (3)
Main airway
Flexibly allows easy movement of food in oesophagus
Contains c.epithelium to trap dust and bacteria before entering lungs
Total lung capacity (TLC)
- Amount of gas in the lungs after max inspiration
How is the nose adapted maximise gaseous exchange (3)
- hairy lining secretes mucus to trap dust and bacteria
- moist surface; denses air to prevent evaporation
- warms air to body temperature
Describe the process of Inspiration in mammals (4)
- Air pressure moves from high on atmosphere to low in thoracic cavity
- Diaphragm contacts and flattens
- Thoracic cavity increases
- Intercostal muscles contract, causing ribs to move upwards and outwards.
Describe the process of expiration (4)
- Air moves from high pressure in thorax to a lower pressure in the atmosphere
- Diaphragm relaxes, turning into a dome shape
- Thoracic cavity volume decreases
- intercostal muscles relax, causing ribs to move down and inwards
Need to specialised exchange surfaces in larger organism (3)
- Metabolic activity is high therefore there is high oxygen demand
- as well as high CO2 production
- have small SA:V ratio, diffusion alone is not enough due to slower rate
Features of efficient specialised exchange surfaces (4)
- Increased surface area (eg root hair cells, villi)
- Thin layers; short distance and therefore quicker rates for diffusion (eg alveoli)
- Good blood supply; steeper concentration gradient allow quicker diffusion. Substances are constantly being delivered and removed (eg alveoli, gills)
- Ventilation; maintains steep concentration gradient (alveoli, fish)
Spiracles (3)
- opening along thorax of insects
- air enters and leaves
- water is lost here
Sphincters
Open (to lose water) and close (to avoid water loss) spiracles, in insects
Describe gas pathway in insects (3)
- Tracheal system; no blood pigments to carry oxygen
- air enters via spiracle
- travels down tracheae
- into the small trachioles which supplies gas to the tissue
Tracheae (3)
- Tube that leads from Spiracle in insects
- carries air into the body
- lined with chitin
Tracheoles (3)
- Single cell exchange surface
- no chitin so that it is permeable to gas
- supplies tissue with gas, therefore very abundant for increase SA
Mechanical tracheal system
- in larger insects
- air pumped by muscles in the thorax
- air pressure changes in tracheal components
Close gas exchange cycles in insects (3)
- spiracle close
- O2 diffuses into cells while CO2 diffuses out
- held in ‘buffering process’
Open gas exchange cycle (3)
- usually when high CO2 is built up
- spiracle open to allow quick diffusion of CO2 out
- pumping could also occur in the thorax to maximise this process
Fluttering gas exchange cycle (2)
- allows fresh air in without losing water
- spiracle opens and closes very rapidly
Advantages of discontinuous gasps exchange
- reduces fungal spore entry
- reduces water loss
- helps insects in enclosed spaces
Describe the adaptations of gills for an efficient exchange surface (4)
Thin layer- short diffusion
Good blood supply- steep concentration
Overlapping tips- more resistance to slow water down for more time for gaseous exchange
Large surface area- increases rate of diffusion
Ram ventilation
- continuous movement in order to ventilate gills
- usually in cartilaginous fish.
Compare main organ for gaseous exchange in fish, mammals and insect
Fish- Gills
Mammals- lungs
Insects- Tracheae and Trachioles
Describe ventilation in fish
- The mouth of the fish opens, which lowers the buccal cavity. The increases the volume and decreases the pressure in the buccal cavity.
- The pressure in the buccal cavity is lower than the surrounds. The causes water to move into the mouth.
- The mouth closes which decreases the volume and increases the pressure in the buccal cavity.
- This causes the operculum to open and causes water to be pushed passed the gill filaments.
- Water moves out of the operculum
Peak flow meter
- fastest rate of air flow from lungs
Structure and function of squamous epithelium for gaseous exchange (2)
- Thin layer, lining for gaseous exchange
- provides a short distance for a diffusion pathway
