:) Exchange And.Transport Flashcards
What do cells need to take in?
Things like oxygen and glucose for aerobic respiration and other aerobic reactions
What do cells need to excrete?
Waste products from these reactions- like carbon dioxide and urea
What does how easy the exchange of substance depend on?
The organisms surface area to volume ratio (SA:V)
Smaller animals have compared to bigger animals?
Higher surface area: volume ratio
Which has the bigger surface area relative to its volume a mouse or a hippo?
A mouse
How can you work this out mathematically?
Hippo block 2cm x 4cm x4cm Volume= 32cm3 Surface area= 64cm2 Hippos SA:V= 2:1 Mouse 1cm x 1cm x 1cm Volume=1cm3 Surface area= 6cm2 SA:V= 6:1
How do calculate surface area to volume ratio?
Surface area/ volume
How to calculate sphere?
4/3 Pi r3
What does an organism need to supply?
Every one of its cells with substances like glucose and oxygen (for respiration)
What does an organism need to remove?
Waste products from every cell to avoid damaging itself
How can a single-celled organism deal with getting what it needs and removing waste products?
Substances can diffuse directly into or out of the cell across the cell surface membrane. The diffusion rate is quick because of the small distances the substances have to travel
Why can’t multicellular animals use diffusion across the outer membrane like single-celled organisms can?
It’s too slow
Give three reasons why in multicellular organisms diffusion is too slow?
Some cells are deep inside the body (big distance between them and outside environment
Low SA:V (difficult to exchange substances to supply large volume of animal through relatively small outer surface)
Higher metabolic rate (use up oxygen and glucose faster)
What do multicellular animals need therefore?
Specialised exchange surfaces like alveoli in the lungs
What do most exchange surfaces have and what are they?
A large surface area
They are thin
Animal example of exchange surface?
Cells on plant root grow into long hairs which stick into soil. Each branch of root coveted in millions of microscopic hairs.
Gives roots large SA:V helped my increase rate of absorption of water (by osmosis) and mineral ions ( active transport) from the soil
Animal example of exchange surface?
Alveoli are gas exchange surface in lungs
Each alveolus made from single layer of thin flat cells (alveolar epithelium)
O2 diffuses out of alveolar space into blood CO2 diffuses into opposite direction
Thin alveolar epithelium helps decrease distance over O2 and CO2 diffusion takes place increasing rate of diffusion.
What else do most exchange surfaces have?
Good blood supply or ventilation
Example in mammals?
Alveoli surrounded by larger capillary network giving each alveolus own blood supply. Blood takes oxygen away from alveoli and brings more carbon dioxide
Lungs
What does every organism no matter what their size need to do?
Exchange things with its environment
Fish example?
Fish gills
Are fish gills to fish?
Exchange surface in fish.
What exchange happens in the gills of a fish
Exchange In the gills, O2 and CO2 are exchanged between the fish’s blood and surrounding water
What features do fish gills have?
a large network of capillaries- keeps them well-supplied with blood.
well-ventilated- fresh water constantly passes over them.
What do these features help the fish do?
These features help maintain concentration gradient of O2 increasing rate at which O2 diffuses into the blood.
Where does air go when you breathe in?
Air enters the trachea (windpipe)
What does the trachea split up into?
Two bronchi- one bronchus leading to each lungs
What does each bronchus branch off into?
Smaller tubes called bronchioles
What do bronchioles end in?
Small air sacs (alveoli) where gases are exchanged.
What work together to move air and out?
The ribcage, inter coastal muscles and diaphragm
What is the gaseous exchange system made of?
Goblet cells Cilia Elastic fibres Smooth muscles Rings of cartilage
Goblet cells
Lining the airways
Secrete mucus
Mucus traps microorganisms and dust particles in the inhaled air stopping them from reaching the alveoli
Cilia
On surface of cells lining the airways
Best mucus
Moves mucus plus trapped microorganisms and dust upwards away from the alveoli towards the throat where it’s swallowed. This helps prevent lung infection
Elastic fibres
In the walls of the trachea, bronchi, bronchioles and alveoli help the process of breathing out. On breathing in the lungs inflate and the elastic fibres are stretched. Then the fibres recoil to help push the air out when exhaling
Smooth muscle
Wall of trachea, bronchi and bronchioles allow their diameters to be controlled. During exercise the smooth muscles relax making the tubes wider meaning there’s less resistance to air flor and air can move in and out of lungs more easily
Rings of cartilage
Walls of trachea and bronchi provide support
Strong but flexible- it stops trachea and bronchi collapsing when you breathe in and the pressure drops
Trachea description of cross section
Outer layer Smooth muscle C-shaped cartilage Elastic fibres Ciliated epithelium Inner layer
Cartilage trachea
Large
C-shaped pieces
Smooth muscle trachea?
Yes
Elastic fibres trachea?
Yes
Trachea goblet cells?
Yes
Trachea epithelium?
Ciliated