Topic 3 - exchange and transport system Flashcards
single celled organism
direct diffusion of oxygen
very high SA:VOL
small mammal
high SA:Vol, faster rate of respiration
big mammal
small SA:Vol, slow rate of respiration
gas exchange in insects
> No transport system,
transported directly to tissue
spiracles and trachea/ tracheoles supply gases,
move in and out through diffusion,
mass transport as a result of muscle contraction
volume changes in tracheoles
covered in waxy cuticle to reduce evaporation
gas exchange in fish
> Small surface are to volume ratio
impermeable membrane (no skin diffusion)
4 pairs of gills supported by arch, gill filaments with lamellar, counter current directional for blood and water - steep diffusion gradient so max oxygen is diffusion into deoxygenated blood
projections are held apart by water
Ventilation - continuous unidirectional flow, 1) opening mouth, lowering the floor of the buccal cavity (water in), 2)close mouth , buccal cavity floor raise (increase pressure), 3) water forced over gill by the difference in pressure between mouth cavity and operculum cavity, 4) operculum acts a valve and pump
gas exchange in Dicotyledenous plants
> mesophyll is where gas exchange for CO2 happens
spongy, Large surface area
gases diffuse in/ out
stomata, short diffusion distance
]> guard cells reduce water loss
air space so gases can move around the lead and come into contact with the mesophyll layer
Xerophytic Adaptions for plants
> curled leaf > stomata sunken in pits > hairs on epidermis (water vapour build up) > thick waxy cuticle (less evaporation) > fewer stomata
Gas exchange in humans
> Lungs - large surface area, external and internal intercostal muscles between ribs contract to raise and lower rib cage
Trachea, bronchi and bronchioles - allow air flow, held open by rings of cartilage, smooth muscles so contract
Trachea and bronchi - thick wall of cartilage, glandular and connective tissue, elastic fibres, smooth muscle and blood vessels in cartilage, inner lining - an epithelial layer of ciliates epithelium and goblet cells
Bronchioles - larger bronchioles contain cartilage, wall of smooth muscle and elastic fibres, alveoli clusters at the end
Mammalian gas exchange system (alveoli)
One cell thick, surrounded by capillaries which are one cell thick - reduces diffusion pathway
Constant blood supply means a steep concentration gradient
Large number of alveoli giving a large surface area
Tidal volume
Volume of air breathed in OR out per breath at rest
Breathing/ventilation rate
Number of breaths per minuet
Pulmonary ventilation
Total volume of air breathed in one minute
Oxygen consumption
Volume of oxygen used per minute
Vital capacity
The maximum volume of air that can be inhaled or exhaled in a single breath
Residual volume
The volume of air which is present in the lungs
Spirometer
Used to measure lung volume
Breath in and out of the airtight chamber, causing it to move up and down, leaves a trace on a graph
inspiratory and expiratory reserves
The tidal volume can be exceeded during exercise when inspiratory reserve volume is reached - to increase the amount of air breathed in
Expiratory reserve volume - the additional volume of air that can be exhaled on top of the tidal volume
pulmonary ventilation equation
PV = tidal volume x breathing rate
Ventilation
Flow of air in and out of the alveoli, two sets of muscles intercostal muscles and diaphragm
Ventilation - inspiration
External intercostal muscles CONTRACT and internal muscles RELAX - ribs raise up
Diaphragm CONTRACTS AND FLATTENS
Increase in thorax volume - lowering pressure
Lung and atmospheric pressure create a gradient - air to be forced into lungs
Ventilation - expiration
Internal intercostal muscles CONTRACT and external muscles relax - lowering the rib cage
Diaphragm RELAXES AND RAISES UPWARDS
Decreases thorax volume - increasing the pressure forcing air out of the lungs
Digestion
Hydrolysis of large biological molecules into smaller molecules which can be absorbed across cell membranes
Carbohydrates
starch to maltose (broken by amylase from salivary gland)
Maltose to glucose + glucose (broken by maltase from small intestine)
lipids
Lipid droplets + bile salts, emulsified to small lipid droplets. Lipase breaks down into micelles
Micelles
Tiny droplets of monoglycerides and fatty acids that release monoglycerides close to the surface of cell
Endopeptidase
Hydrolyse peptide bonds within a polypeptide
Exopeptidase
Hydrolyse peptide bonds at the end of the peptide