State the uses of energy in living organisms?
Organisms need energy for
1. muscle contraction,
2. protein synthesis,
3. cell division,
4. active transport, growth,
5. transmitting nerve impulses
6. and maintaining a constant body temperature.
• identify the organs in the
respiratory system in
diagrams and images
• explain the role of goblet
cells, mucus and ciliated cells
in protecting the gas exchange
system from pathogens and
Particles
• Describe aerobic respiration, and write the word equation for it.
• Respiration is a metabolic reaction that takes place in all living cells, and releases energy from
glucose and other nutrient molecules.
• There are two type of respiration Aerobic and anaerobic respiration
• Aerobic respiration happens in mitochondria.
• Oxygen is combined with glucose, releasing a lot of energy and producing carbon dioxide and
water.
• Describe anaerobic respiration in human muscles and in yeast, and
write the word equations for them
• Anaerobic respiration happens in the cytoplasm.
• Glucose is broken down without using oxygen, releasing a small amount of energy.
• In humans, lactic acid is produced. This happens when you do vigorous exercise, and your lungs
and heart cannot supply oxygen to your muscles as quickly as they are using it.
In yeast, carbon dioxide and ethanol are produced.
The air path inside the body.
Air moves to them through the trachea, bronchi and bronchioles and in alveoli.
Each lung is filled with many tiny air spaces called air sacs or alveoli.
It is here that oxygen diffuses into the blood, so the surface of the alveoli is the gas exchange
surface.
The nose and mouth
• Air can enter the body through either the nose or mouth.
• Nose contain cell with hair like projection called cilia and goblet cell.
• The cilia are always moving, and bacteria or particles of dust get trapped in them
and in the mucus up to the back of the throat, so that it does not block the lungs.
Cilia are found all along the trachea and bronchi, too.
Goblet cells, that make a liquid containing water and mucus. Mucus trap particles in
the air.
The water in this liquid evaporates into the air in the nose and moistens it.
The trachea
• the air then passes into the windpipe or trachea.
• Below the epiglottis is the voice box or larynx that contains the vocal
cords.
• The vocal cords can be tightened by muscles so that they make sounds
when air passes over them.
• The trachea has rings of cartilage around it.
• As you breathe in and out, the pressure of the air in the trachea increases
and decreases.
• The cartilage helps to prevent the trachea collapsing at
times when the air pressure inside is lower than the pressure
of the air outside it.
The bronchi
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The trachea goes down through the neck and into the thorax.
The thorax is the upper part of your body from the neck down to the bottom of the
ribs and diaphragm.
In the thorax, the trachea divides into two.
The two branches are called the right and left bronchi (singular: bronchus).
One bronchus goes to each lung and then branches out into smaller tubes
called bronchioles
• Describe the features of gas exchange surfaces in
humans
• The place where oxygen enters an organism’s body
and carbon dioxide leaves is called the gas
exchange surface.
• Exchange surface is the alveoli in the lungs.
They have other characteristics which help the process
to be quick and efficient:
• They are thin to allow gases to diffuse across them
quickly.
• They are close to an efficient transport system to take
gases to and
from the exchange surface.
• They have a large surface area, so that a lot of gas
can diffuse
across at the same time.
• They have a good blood supply of oxygen.
• investigate the differences in carbon dioxide content between inspired air and expired air, using
limewater
Inspired air contains more oxygen and less carbon dioxide than expired air.
• explain the roles of ribs, and the external and internal intercostal muscles, inbreathing, and how changes
in volume and pressure in the thorax produce air movements
The intercostal muscles and the diaphragm cause breathing
movements, which ventilate the lungs.
1. When breathing in or inspiration
• the diaphragm and external intercostal muscles contract,
• Diaphragm is lowered
• The rib cage is raised
• increases the volume of the thorax
• therefore reduces the air
• pressure in the lungs.
2. When breathing out, or expiration
• The diaphragm and external intercostal muscles relax.
• The diaphragm springs up
• The rib cage is lowered
• The volume of thorax decreases
• So air is forced out of the lungs
Explain the effects of physical activity on rate and depth of breathing, including reference to lactic acid and
oxygen debt, and the control of breathing rate by the brain
Physical activity causes the rate and depth of breathing to increase, in order to
supply extra oxygen to muscles.
The depth and rate of breathing is controlled by the brain, which detects a
decrease in the pH of the blood when it contains more carbon dioxide or lactic acid
than usual. If there is a lot of carbon dioxide or lactic acid in the blood, this causes
the pH to fall.
When the brain senses this, it sends nerve impulses to the diaphragm and the
intercostal muscles, stimulating them to contract harder and more often.
The result is a faster breathing rate and deeper breaths.
During exercise, faster aerobic respiration by muscles produces more carbon
dioxide, and
therefore results in an increase in breathing depth and rate.
During intense physical activity, muscles may use anaerobic respiration as well as
aerobic respiration, to supply extra energy. But this produce lactic acid.
After exercise has finished, the lactic acid produced is broken down in the liver by