Transcript Document 644050

Need for Transport
National 5 Biology
Learning Outcomes
• Explain why multicellular organisms require transport
systems
• Explain why plants require a transport system for water
• State the name for the movement of water through a plant
• State the structures involved in the transport of water in
plants
• Describe the structure and function of xylem
• Describe the function of guard cells
• Name environmental factors which increase the rate of
transpiration in plants
• Explain why plants require a transport system for sugar
• State the structure involved in the transport of sugar in
plants
SA : V Ratio
Edge of Cube
Area of Face
Total Surface
Area of Cube
Volume of Cube
1cm
1 cm2
6cm2
1 cm3
Surface Area to
Volume Ratio
(SA:V)
6 : 1:1
1
2cm
3cm
4cm
5cm
6cm
The larger the organism, the smaller its SA : V ratio
Larger organisms need transport systems to carry
raw materials.
Plant Transport
• Think –
• What needs to be transported about inside
plants?
• We need to find out more about how it
happens and the problems that arise.
http://www.twigonglow.com/films/plant-transport-1187/
Xylem
They have no cell contents and no nucleus. They
are dead cells.
The end walls have broken down and have
disintegrated.
Side walls are strengthened by lignin to prevent
damage by water pressure
Transport of water
lignin
xylem vessel
Transpiration
Plants need water for photosynthesis.
It is absorbed in the roots and evaporated out of leaves.
http://www.twigonglow.com/films/glossary/transpiration-441/
Transpiration Rate
• Various factors will affect the rate of
transpiration.
• This includes
light
temperature
humidity
wind
Potometer
• Transpiration rate can be measured using a
potometer.
• Changing conditions around the potometer will
change the rate of transpiration
Leaf Structure
cuticle
upper
epidermis
mesophyll layer
vein
moist air space
guard cells
stoma
lower
epidermis
Leaf Structure
Part
Upper
Epidermis
Mesophyll
layer
Function
Protective layer. Transparent to let light in
Cells contain chlorophyll for photosynthesis
Contains xylem and phloem for transport
Vein
Pores on surface to allow gas exchange
Stoma
Guard cells Cells to control gas exchange by opening
Moist air
space
Large surface area to help gas exchange
Guard Cells
• Water enters guard cells
• Water lost from guard cells
• Guard cells become turgid
• Guard cells become flaccid
• Thin outer wall stretches more
than thick inner wall
• Walls not stretched
• Stoma opens
• Stoma closes
Plant Transport
• http://www.twigonglow.com/films/planttransport-1187/
Phloem
Columns of sieve tubes,
with sieve plates at either
end.
sieve tube
Companion cells sit
next to the sieve
tubes.
companion cell
They have a dense
cytoplasm and a nucleus.
sieve plates with pores
nearby cell
They are living cells.
Stem cross section
Root cross section
Learning Outcomes
• Describe the structure of the heart - include names of chambers, blood vessels
entering and leaving the heart
• Describe the position and the function of valves in the heart
• Describe the pathway of blood through the heart, lungs and body
• Describe the structure and function of arteries, veins and capillaries
• Explain how the structure of a capillary network is related to its function
• State what is carried in the blood
• State the location and function of haemoglobin
• Explain the need for iron in the diet and health problems when there is a lack of iron
The heart
The heart is made of a special type of muscle called
cardiac muscle, which doesn’t get tired.
The job of the heart is to pump blood around the
body.
The heart can be thought of as a muscular pump.
http://www.twigonglow.com/films/heart-976/
The heart
right atrium
right ventricle
Left atrium
left ventricle
The heart has four chambers. The heart is shown from the front. Like it is in your
body…the left hand side is nearest your left arm etc…
The heart
Blood contains (as well as many other things) dissolved food,
and gases (e.g. oxygen and carbon dioxide.
Every cell in the body needs food and oxygen.
The blood from the heart must reach all cells, so that
means the heart needs its own blood supply too .
coronary
artery
The coronary artery supplies food and oxygen to the cells of
the heart muscle. When these blood vessels get blocked, you
can suffer a heart attack.
The heart
from
body
to
lungs
The ventricles have thicker walls than the
atria.
to
body
from
lungs
left atrium
from
body
left ventricle
right ventricle
The left ventricle has a
thicker wall than the right
ventricle because the left
ventricle has to pump
blood right around the
body and the right
ventricle only has to pump
blood to the lungs.
The heart
vena
cava
pulmonary
artery
Arteries go away from
the heart.
aorta
pulmonary
vein
Veins return to the heart.
vena
cava
A pulse indicates that blood is flowing through an artery.
Can you find your own pulse?
Circulation around body
Pulmonary
artery
Vena Cava
Pulmonary
vein
Aorta
Blood flow through the heart
Deoxygenated blood i.e. low in oxygen returns to
the heart via the vena cava after travelling to
all parts of the body. It enters the heart at the
right atrium
atrium.
The right ventricle then pumps blood out
through the pulmonary
pulmonary artery to the lungs.
lungs
In the lungs the blood picks up oxygen and loses
dioxide
carbon dioxide.
The oxygenated blood then returns to the heart
via the pulmonary vein,
vein entering the left atrium.
The left
left ventricle pumps blood out through the
aorta to the body.
The heart
Valves between ventricles
and blood vessels
The heart has two sets of valves.
Valves can be open or closed (like gates).
Valves stop blood flowing backwards (ie the wrong
way).
One set of valves are found between the two atria
and the ventricles – blood can’t flow back into the
atrium.
Valves between atria and
ventricles
The other set of valves are found between the two
ventricles and the blood vessels leaving the heart –
blood can’t flow back into the ventricles.
Valves act like a one way street
Valves
Veins/arteries
heart
veins
arteries
capillaries
The heart and blood circulation
Every cell in the body needs food and
oxygen.
The blood circulation must reach all cell
Arteries carry oxygenated blood
(high in oxygen) from the heart
around the body.
blood
vessels
arteries
veins
Veins carry deoxygenated blood
(high in carbon dioxide) back to the
heart.
The exception is the pulmonary artery, which carries blood high in carbon dioxide
from the heart to the lungs.
Arteries Veins and Capillaries
Arteries have thick walls to withstand the
high pressure of the blood being pumped by
the heart.
Arteries divide into smaller blood vessels and
finally into tiny capillaries.
Arteries Veins and Capillaries
Capillaries are in close contact with
the living cells.
They are only one cell thick.
They allow water, gases and other
substances, to pass to between the
blood and the body’s tissues.
Arteries Veins and Capillaries
Veins have thinner walls than arteries.
They carry the deoxygenated blood (high in carbon
dioxide) blood back to the heart.
They have thinner walls because the deoxygenated
blood is at low pressure.
Veins have valves to prevent the backflow of blood.
The pulmonary vein, which carries blood high in oxygen from the lungs to the heart
is the exception.
Arteries Veins and Capillaries
Blood is carried away from the heart in arteries.
arteries
organs
These arteries carry blood to the body’s organs
and tissues.
In the organs the arteries split up into a network of tiny tubes called
capillaries
capillaries.
Substances are exchanged between the capillaries and the tissues.
veins
Blood leaves the tissues in vessels called veins
back to the heart.
which carry the blood
Gas exchange at the tissues
Oxygen diffuses
diffuses from the high concentration in the capillary blood
across into the body cells. Carbon dioxide diffuses from the high
concentration in the cells into the plasma
plasma.
Blood from artery
high oxygen
low carbon dioxide
Blood to vein
high carbon dioxide
low oxygen
living cell
CO2
oxygen
capillary
CO2
More about Capillaries
The capillary network allows efficient exchange of gas, food and waste
because
thin n walled which gives a greater surface
surface area to
1. They are narrow and thi
allow fast diffusion of gases etc.
2. They are very long
long which also increases the surface area.
3. No cell is ever far away from a capillary thus ensuring easy exchange.
http://www.twigonglow.com/films/blood-971/
Red blood cells and plasma
Blood is made up of cells floating in a liquid
called plasma.
The plasma also carries dissolved substances
food and
such as carbon
carbondioxide,
dioxide digested food
waste products.
Red blood cells carry oxygen
oxygen
http://www.twigonglow.com/films/why-is-blood-red-978/
Haemoglobin
A red pigment called haemoglobin
haemoglobin is found in red blood cells. Its
function is to combine with oxygen to form oxyhaemoglobin.
At the lungs, haemoglobin combines with oxygen to make
oxyhaemoglobin.
At the tissues, oxyhaemoglobin releases oxygen and becomes
haemoglobin again.
at lungs
haemoglobin
+ oxygen
oxyhaemoglobin
at tissues
Learning Outcomes
• Describe the structure and function of the lungs
• Explain the function of the rings of cartilage in the trachea
• Describe the function of cilia and mucus in the trachea
• Describe gas exchange within the alveoli
• Explain how the structure of the lungs is related to their
function
Respiratory system
• To carry out respiration, the body needs a
supply of oxygen. It gets this from the air.
• The respiratory system extracts oxygen form
the air to make it available [via the blood] to
the respiring cell.
http://www.twigonglow.com/films/lungs-981/
Respiratory System Structures - Revision
nasal cavity
trachea
air sac
bronchus
intercostal
muscle
Left lung
ribs
heart
diaphragm
Lung Structure
Lungs are spongy organs full of tiny air
sacs called alveoli.
They have a very large surface area.
They are pinky red because they have a
good blood supply.
Rings of cartilage are found around the
trachea and the bronchi to prevent them
from collapsing.
http://www.twigonglow.com/films/factpack-lungs-982/
The lining of air passages
Air contains dust and germs which could damage your lungs.
The cells lining the air passages have small hairs or cilia.
The cilia move in waves to push upwards and keep the lungs clear.
(produce mucus)
Lung Structure
Gas exchange in the air sacs
The bronchi divide into smaller
and smaller tubes called
bronchioles.
Each bronchiole ends in an
air sac, which is lined in
moisture.
Oxygen dissolves in moisture
and diffuses from lungs into
blood because there is a higher
concentration in the air sac
than in the blood.
Carbon dioxide diffuses in
opposite direction because
there is a higher concentration
in the blood than in the air sac.
The alveoli
Oxygen and carbon dioxide are exchanged between the air and blood in the alveoli.
There are many thousands of alveoli.
Importance in Multicellular Organisms
oxygen
carbon dioxide
Learning Outcomes
• State the function of the digestive system
•
• Name the parts of the digestive system and give their
function
•
• Describe the process of peristalsis
•
• Explain how the structure of the small intestine is related
to its function
•
• State where glucose, amino acids, fatty acids and glycerol
are absorbed within the villi
The Alimentary Canal
The alimentary canal leads from the mouth to the anus.
Associated organs are connected to it – the salivary glands,
liver and pancreas by ducts.
1. Digestion in the mouth
Digestion begins in the mouth with mechanical breakdown of
food by teeth and chemical breakdown of starch by the
enzyme amylase.( made in salivary glands)
Saliva contains mucus so food is easy to swallow.
Oesophagus and Peristalsis
Oesophagus is a muscular tube - connects the mouth to
stomach.
It is the start of the alimentary canal, which is a long tube
stretching from mouth to anus.
When food is swallowed wave-like muscular contractions
called peristalsis ensures the food (bolus) moves down in
a slow controlled way no matter what position the body is
in.
The muscle ahead of the food is relaxed while the muscle
behind the food contracts.
Peristalsis
Muscles behind food
contracted
Direction
of
Food
food
movement
Muscles ahead of food
relaxed
Stomach
The stomach is a muscular sac with longitudinal and circular
muscles that contract and relax, churning or mixing food with
acid and enzymes.
The mucus, lining the stomach protects the wall from being
damaged by the acid ( pH 2).
Acid provides the correct pH for the protein digesting enzyme
pepsin to work.
pepsin
protein
Peptides
Small Intestine
As food leaves the stomach, it enters the small intestine.
The first 12 inches make up the duodenum.
There are 2 ducts connected to this :
a) Pancreatic : enzymes made by the pancreas enter through
this. ( lipases,amylases and proteases, an example of a
protease is trypsin)
b) Bile : bile stored in the gall bladder enters through this.
Bile is made in the liver but stored in the gall bladder.
Bile emulsifies fats ( gets them to mix with water) and neutralises
the acid soaked food coming from the stomach as it is an
alkali.
Small Intestine
The main job of the small intestine is to absorb the
products of digestion.
It is well adapted for this by :
•Long and inner membrane is highly folded. This
increases the surface area for absorption
•Thin inner lining ,only one cell thick.
• Many blood capillaries to absorb and transport
products. Lacteals are present to transport fats
Villi in small intestine 100x
Small intestine villus
Fate of Digested Food
Glucose, amino acids ( products of carbohydrate and
protein digestion) are absorbed into the blood
capillaries
Fatty acids and glycerol are absorbed into the lacteal.
Next Step – Liver !
The liver decides how much sugar is needed in the
blood and converts the excess to glycogen and stores it.
Liver
The liver decides how much amino acids should be in
the blood and converts the excess to urea.
This urea is taken to the kidneys for excretion in urine.
Fatty acids and glycerol travel in the lymphatic system.
Excess is stored as fatty tissue.
Large Intestine
Material passing into the large intestine consists of
undigested matter ( fibre), bacteria and dead cells .
The colon absorbs water from this before eliminating
the waste as faeces.