Transport systems in living things Flashcards
(32 cards)
Why is there a need for a
transport system in humans,
plants & animals?
● Humans are complex organisms made up of millions of cells
● Most of these cells are far away from the outside of the organism and cannot get
materials directly from the environment
● A transport system is needed to take substances to all the cells and to carry waste substances
away
What are the two transport processes?
- Diffusion
- Osmosis
What is diffusion?
The net movement of particles from a region of higher concentration to a region of lower concentration
What is osmosis?
The net movement of water molecules from a region of higher water potential to a region of lower water potential through a partially permeable membrane.
osmosis is a type of diffusion that…
- Only involves water molecules
- Requires a partially permeable membrane
What is the function of the heart?
● The walls of the heart are made of muscles
● Muscles contract and relax, allowing the heart to pump blood around the body
What are Cornary arteries?
Coronary arteries are blood vessels that transport oxygen and nutrients to the heart muscles
What harmful effects can occour in Cornary arteries?
● Fatty substances may build up inside them
● Blockage can lead to a heart attack
● Heart muscles may get damaged or die
What are the two main functions of blood?
- To transport materials around the body
- To protect us against diseases
What is the composition of blood?
-55% plasma
-44% blood cells
-1% platelets
What are the characteristics of red blood cells?
● No nucleus
● Contains haemoglobin, which combines with oxygen and transports it around the body
● Bright red in colour when they carry oxygen
● Biconcave shape increases its surface area to volume ratio, allowing oxygen to diffuse into it at a higher rate
What are the characteristics of white blood cells?
● Contains nucleus
● Lacks haemoglobin (colourless)
● Irregular in shape
● Larger than red blood cells
● There are fewer white blood cells than red blood cells
● Keeps body healthy by fighting disease
What is plasma?
A pale yellow liquid made up of
● water (90%)
● dissolved substances (10%)
What is the function of plasma?
Plasma transports water and
substances around the body.
What is the chracteristics of platelets?
● Not true cells
● Fragments of cytoplasm
What is the function of platelets?
Play a part in blood clotting
● prevents excessive blood
loss
● prevents entry of germs
into the blood
What is the difference between the veins and the arteries?
veins carry blood to the heart while the arteries carry blood away from the heart
What is the function of the artery?
Carry blood away from the heart
What is the structure of the artery?
Arteries have walls which are thick,muscular and elastic.
Why does arteries need thick,muscular and elastic walls?
-Arteries need to withstand the immense pressure of the blood as it is forced out of the heart. —-Thick elastic walls help to withstand the high blood pressure in the artery.
What is the function of the vein?
Carry blood to the heart
What is the structure of the vein?
-Walls of the veins need not be as thick and muscular as those of arteries
-Veins contain less elastic tissue than arteries
Why does the vein need not have thick,muscular and elastic walls compared to arteries?
● Blood pressure in the veins is much lower than the blood pressure in the arteries
● Blood flows more slowly and smoothly in the veins
What is the function of the capillary?
Carry substances to and from cells
