Section1- Exchange and transport

Components of the gas exchange system in fish

• Gill arch

• Gill filaments

• Lamella

Adaptation of the lamella

• Flat layers

• Short diffusion pathway

• Surrounded by capillaries

Adaptation of gill filaments

Increase surface area

Parallel flow

Conc gradient will level out when blood and water are both 50% saturated with oxygen

Countercurrent flow

Blood will continue absorbing oxygen from the water as the conc gradient does not level out

Buccaneers-opperculum pump

• Floor of buccal cavity moves downwards this increases in volume the buccal cavity

• Pressure of water in buccal cavity decreases and water flows in from outside through open mouth

• Once buccal cavity has filled, the mouth closes and the floor of the buccal cavity moves up decreasing the volume

• Pressure increases and pushes the water backwards through the gills

Components of tracheal system

• Head

• Thorax

• Abdominal cavity

• Spiracles

• Trachea

• Tracheoles

Adaptation of trachea in tracheal system

• Lined with chitin(spirals)→ provides support and keeps them open

• 1mm thick

Functions of spiracles

Gas exchange and controls water loss

Adaptation of tracheoles in tracheal system

• 0.6-0.8mm

• Branch into the tissue and where gas exchange takes place

Tracheal system solution to build up of water at the bottom of the tracheoles

• Lactic acid begins to build up in the cells

• Decreases the cell water potential causing water to move back into the cells

Mechanical ventilation

Air is actively pumped into the system by muscular pumping movement→ this changes the volume and pressure in the trachea and tracheoles

Wing volume and thoracic volume changes

Abdominal breathing movements

Uses abdominal muscles to create a pumping movement for ventilation, increasing the volume and decreasing the pressure so air moves in and out

Air sacs

Act as air reserves by inflate and deflating through ventilating movements of the thorax and abdomen

Explain how a spirometer works

• Carbon dioxide is absorbed from the exhaled air by soda lime

• A trace is drawn which will show tidal volume, vital capacity and breathing rate can all be calculated

• Due to carbon dioxide being absorbed the total volume of air available in the spirometer will gradually decrease as oxygen is extracted by the participant breathing

Rate of diffusion equation

Rate of diffusion∞ Surface area x concentration difference/ thickness of membrane

Surface area anode volume equation of a cube

SA: (4xlengthxheight)+(2xheightxwidth)

Volume: length x width x height

Surface area and volume equation for cylinders

Surface area: (2πr x height) + 2πr²

Surface area and volume equation for spheres

Surface area: 4πR²

Volume: 4/3πR³

Name and explain Features of efficient gas exchange

• Large surface area→ provides a large area over which the exchange of materials can occur

• Thin layers→ short diffusion pathway

• Blood supply→ good, constant blood supply maintains a large diffusion gradient and ensure the exchanged substances are constantly moving to the area needed

• Ventilation→ maintains the diffusion gradient, makes the process faster and more efficient

Components of the respiratory system

• Nasal cavity

• Nostril

• Mouth

• Trachea

• Bronchus

• Bronchioles

• Larynx

• Intercostal muscles

• Pleural membrane

• Ribs

• Diaphragm

• Abdominal cavity

• Alveoli

Adaptations of the nasal cavity

• Large SA=good blood supply

• Hairy lining= traps dust + produces mucus

• Moist= increases humidity for incoming air and reduces water lost via evaporation

Adaptations of pleural membrane

• Lubricates the lungs

• Adheres the outer walls of the lungs to the thorax by water cohesion

• Allows the lungs to expand the chest while breathing

Trachea adaptations

• U rings of cartilage to hold trachea open and prevent it from collapsing→ incomplete ring allows trachea to expand when food is swallowed

Features and components of trachea

• Cartilage→ prevent airway closing

• Smooth muscle/ elastic fibres→ Constrict= decrease SA widen= increases SA

• Ciliate epithelial→ wafts mucus

• Goblet cells→ produce mucus

• Small blood vessels

• Mucus glands→ secretes mucus

Goblet cells

Produce mucus

How do elastic fibres help the alveoli

Causes recoil which helps move the air out of the alveoli

Intrapulmonary pressure

Pressure within the alveoli of the lungs

Intrapleural pressure

Pressure within the pleural cavity

What happens in inspiration?

• Rib cage up and out

• Internal inter coastal muscle relax

• External intercostal muscles contract

• Diaphragm contracts and flattens so moves down

• Intrapulmonic pressure decreases below atmospheric pressure

Explain what happens in expiration

• Rib cage moves down and in

• Internal intercostal muscles contract

• External intercostal muscles relax

• Diaphragm relaxes and moves upwards

• Intrapulmonic pressure increases above atmospheric pressure

• Passive process except when forced out

Intrapulmonic pressure

Pressure in the lungs

Tidal volume

Total volume of air inhaled or exhaled in one normal breath

Inspiration reserve volume

Max volume of air breathed in over and above the normal volume

Expiratory reserve volume

Max volume of air you can force out of your lungs over and above your normal volume

Vital capacity

Largest volume of air inhaled and exhaled in one breath

Residual volume

Volume of air left in your lungs when you exhale

Total lung capacity

The sum of the vital capacity and residual volume

Calculation for breathing rate

Ventilation rate/ tidal volume= breathing rate (per min)

Calculating oxygen consumption

Volume/ time

Measuring tidal or4 vital capacity

Measure from peak of trough of a single wave

Lung surfactant

Phospholipid that coats the surface of the lungs and helps gases to dissolve