Topic 3A: Exchange and Transport System Flashcards
Name something that essensial to cells
Oxygen
Name 2 waste products that organisms excrete
carbon dioxide & urea
What does an organisms SA:V ratio effect?
how quickly substances are exchanged
Do larger or smaller organisms have a higher SA:V ratio?
smaller
How do you work out volume (cm3)?
lxhxw
How you work out surface area (cm2)?
hxwx how many faces
How do you calculate volume of a cylinder?
pie r2 x h
How do you calculate volume of a sphere?
4/3 pie r3
Explain diffusion of single-celled organisms?
Diffuse directly in/out of the cell across the cell-surface membrane
Diffusion rate is fast due to the small distances substance must travel
Do multicellular organisms diffuse across the membrane slowly and quickly?
Slowly
Name 2 factors affecing the rate of diffusion
a thin exchange surface- alveolar epithelium only one cell think and a large exchange surface
what 2 things does lung disease affect
ventilation and gas exchange
what is tidal volume
the volume of air in each breath (between 0.4-0.5dm3)
what is ventilation rate
number of breaths per min (15 breaths healthy)
what is forced expiratory volume (FEV)
max volume of air that can be breathed out in one second
what is forced vital capacity (FVC)
max volume of air its possible to breath forcefully out of the lungs after a really deep breath in
what do lung diseases do to gas exchange
all reduce the rate of gas exchange in the alveoli, less oxygen is able to diffuse into the blood stream so body cells recieve less oxygen
name and explain the 2 reasons why multicellular organisms diffuse across the outer membrane slowly
some cells are deep within the body, big distance between them and the outside environment
larger animals have low sa:v ratio difficult to exchange enough substances to supply increased volume of animal through small outer surface
what do multicelular organisms need to absord/discrete substances
specialised exchange organs
what does rate of heat loss from an organism depend on
surface area
if an animal has a large volume what does this mean in relation to heat loss
small sa so harder to lose heat from its body
because of the a small SA what does this mean for their metabolic rate (why)
low in large animals, high in small animals to generate enough energy to stay warm
whats good about having a compact shape (animal)
animals with q compact shape have a small sa:v ratio, minimising heat loss from their surface
what does an animals body shape depend on
temp of its environment
do animas with a high sa:v ratio lose lots/little water
lose more water as it evapourates from their surface
the trachea branch into what
tracheoles
explain features of tracheoles
thin, permeable walls and go to indiviual cells
what are tracheoles needed form
means that oxygen diffuses directly into the respiring cells the insects circulatory system doesn’t transport o2
co2 from cells moves down its own conc gradient towards the spiracles released into the atmosphere
name the structures used in breathing (IN ORDER)
tranchea - 2 bronchi - bronchus - bronchioles - alveoli - alveolus
explain intercostal musces
found between the ribs, 3 layers of them (internal and external)
what are the 2 processes that occur during ventilation
inspiration and expiration
explain inspiration
external intercostal and diaphragm muscles contract, causing the ribcage to move upwards and outwards and the diaphram flattens, increasing the volume of the thoratic cavity increases
lung pressure decreases below atmospheric pressure
airflows low-high pressure active process
explain expiration
external intercostal and diaphragm muscles relax, ribcage moves down and inwards
diaphragm curves upwards again
the volume of the thoratic cavity decreases, causing the air pressure gradient and out of the lungs
passive process and can be forced
what are capillaries surrounding
alveoli
what are the walls of each alveolus made from
walls made from single layer of thin, flat cells called alveolar epithelium
what are the walls of the capillaries made from
capillary endothelium
whats the protein called in the walls of each alveolus
made from elastin
explain gas exchange in the alveoli
o2 diffuses out of the alveoli, across the alveolar epithelium and the capillary endothelium and into Hb in the blood
co2 diffuses into the alveoli from the blood
why is losing more water when an animal with increased SA:V ratio and how do they compensate (living in hot conditions)
water evaporates quickly, some small desert mammals have kidney structure adaptations so they produce less urine to compensate
what do small animals need to do to support their high metabolic rates
eat large amounts of high energy foods (seeds and nuts)
what might small mammals have when the weather gets really cold
fur or hibernate
what is created when gas exchange occurs over a gas exchange surface
a boundary between the outside environment and internal environment of an organism
name the 2 most common things that increase rates of diffusion
large SA, thin (short diffusion pathway)
explain gas exchange in single-celled organisms
absorb and release gases by diffusion through their membranes
they have a high SA a thin surface and a short diffusion pathway
where does gas surface exchange occur
gills
what is the counter-current system
in the gills of a fish blood flows through the lamellae in one direction and water flows over them in the opposite dircetion
what does the counter current system mean for the water/oxygen
Means that the water with a relatively high o2 con always flows next to the blood with low o2 conc
meaning steep conc gradient is maintained
where is the main gas exchange surface in plants
mesophyll cells
how are mesophyll cells adapted for gas exchange
increased SA
explain somata
gases move in and out through special pores in the epidermis called stomata
they can open to allow gas exchange and close if the plant is lossing too much water
guard cells control the opening and closing
what are tracheae
microscopic air-filled pipes
what are the pores on the tracheae called
spiracles
explain the structure of the gills
water containing oxygen enters the fish through its mouth and pass out through the gills
each gill is made of lots of thin plates called gill filaments, giving anlarge sa
gill filaments are covered in lots of tiny structures called lamella, increases sa more
lamella have lots of blood capillaries and thin surface layers of cells to speed up diffusion between h2o and blood
