exchange and transport systems Flashcards
the rate of heat loss depends on what
surface area
animals with a compact shape have a what surface area
small surface area
why do compact animals have a small surface area
minimises heat loss from their surface
what are the 2 main adaptations for gas exchange surfaces
large surface area
thin walls( one cell thick)
where do single celled organisms undergo diffusion
on their outer surface
why do single celled organism not need a gas exchange system
they have a large SA
thin surface and short diffusion pathway
where does oxygen enter and leave in fish
in water through the mouth and passes out through gills
what are the thin plates that make up the gills called
gill filaments
what do the gill filaments do
give a big surface surface area for exchange of gases
what are the gil filaments covered in
tiny structures called lamellae
what is the function of the lamellae
increase surface area even more
how are he lamellae adapted to carry out diffusion
thin surface layer of cells to speed up diffusion and lots of capillaries
explain the counter-current system in fish
blood flows through lamellae in one direction and water flows in opposite
why is the counter current system good in fish
it maintains a large concentration gradient between water and blood
is there a higher concentration of water or blood naturally in fish and what does this mean
water so oxygen diffuses from water into the blood
what do insects use for gas exchange
air filled pipes called trachae
how does air move into the trachea of insects
by pipes called spiracles
what do the trachae break of into
smaller tracheoles
how are the trachae adapted and why
thin, permeable walls an go directly to individual cells
how does carbon dioixide move out of insects
towards the spiracles to be released from the atmosphere
how do insects move air in and out
rhythmic abdominal movements
what is the main gas exchange surface on plants
on the surface of the mesophyll cells
how is the surface of the mesophyll cells adapted for gas exchange
have a large surface area
where do gases move in and out of in a plant
pores in the epidermis called stomata
what do insects do if they are loosing too much water
close their spiracles using muscles
how are insects adapted to conserve water
have a waxy cuticle and tiny hairs around spiracles which reduces evaporation
how are plants adapted to conserve water
guard cells loose water making them flaccid which closes the pores
what kind of plants are adapted for extreme conditions
xerophytes
how are the stomata adapted in xerophytes
they are sunk in to trap moist air , reducing concentration gradient between leaf and air , reducing evaporation
what is inspiration
breathing in
what does the layer of hairs on the epidermis do for xerophytes
traps moist air round the stomata
what do the curled leaves on xerophytes do
protect the stomata from wind
what happens in the first stage of inspiration
what happens in the second stage of inspiration
external intercostal and diaphragm muscles contract
ribcage moves up and out, diaphragm flattens volume of thoracic cavity increases
what happens in the 3rd stage of inspiration
lung pressure decreases as volume of thoracic cavity increases
what direction does air always flow and what does this mean for the lungs
from high pressure to low pressure so from trachea to lungs
what kind of process is inspiration and what does this mean
active process so requires energy
what is expiration
breathing out
what happens in the first 2 stages of expiration
external muscles relax and internal contract
ribcage move downwards and inwards and diaphragm becomes curved
what happens to the volumes in expiration
- thoracic cavity
- lungs
volume of TC decreases so air pressure increases
air is forced out of the lungs as it moved down pressure gradient
can expiration be forced
yes
what happens during forced expiration
external intercostal muscles relax and internal contract
moving ribcage down and in
what can the movement of the intercostal muscles be described as during expiration
antagonistic
what are the 2 ways alveoli are adapted for gas exchange
thin exchange surface- one cell thick so a short diffusion pathway
large surface area
what is tidal volume
volume of air in each breath
what is ventilation rate
number of breaths per minute
what is FEV
forced expiratory volume - maximum amount of air you can force out
what happens when someone has pulmonary tuberculosis
cells build up a wall of bacteria in the lungs
infected tissue dies and gas exchange susyem is damaged
what does reduced tidal volume lead to
less air that can be inhaled with one breath
what are some common symptoms of tuberculosis
persistent cough, coughing up blood or mucus
chest pain
shortness of breath
fatigue
what is fibrosis and what can it be a result of
formation of scar tissue in the lungs
infection or exposure to asbestos/ dust
why is scar tissue bad for the lungs
thicker and less elastic then normal tissue
so lungs arent able to expand so cant hold as much air
what does fibrosis result in for the lungs
reduced tidal volume
reduction in rate of gaseous exchange
fast ventilation rate
what happens in asthma
airways become inflamed and irritated
what happens during an asthma attack
smooth muscle lining contracts and lots of mucus is produced
what is a result of the mucus production in asthma
constriction of the airways, reduced air flow so FEV reduced
what are some symptoms of asthma
wheezing
shortness of breath
increased ventillation rate
what is emphysema caused by
smoking or air pollution
what does emphysema cause
inflammation which attracts phagocytes to the area which produce an enzyme which breaks down elastin