Human Health & Systems Flashcards
Stages of nutrition
Ingestion / eating: food is taken in by the body
Digestion: food is broken down
Absorption: digested food passes into the bloodstream
Assimilation: using the food in the cells of the body
Elimination: getting rid of indigested food
Ingestion / eating:
food is taken in by the body
Absorption
Physical digestion
• taking large pieces of food and breaking them down into smaller pieces
Happens in the •mouth (teeth) and •
Chemical digestion
Involves the use of chemicals called enzymes to break down food
Enzymes are chemicals that speed up reactions without being used up in the reaction
Enzymes act on a substrate and breaks it down into a product
Example: substrate = starch,, Enzymes = amylase (saliva),, Product = maltose (sugar)
enzymes
Enzymes are chemicals that speed up reactions without being used up in the reaction
Chemical digestion
• amylase in mouth
• enzymes in the stomach
• most chemical digestion happens in the small intestine
• bile made in liver to break down fats
• pancreas makes digestion juices which contain enzymes
In a cigarette
- Acetone
- Mercury
- Lead
- Nicotine
- Cadmium
- Carbon Monoxide
- Hydrogen Cyanide
- Urethane
- Arsenic
- Phenol
- Formaldehyde
- DDT
Anaerobic Respiration
does not use
oxygen to release energy from food.
Aerobic Respiration
needs oxygen to
release energy from food.
How does Oxygen get to our
Cells??
• Oxygen is carried by the haemoglobin in
red blood cells to all other cells of the body
Remember!
Much less energy is released from food by
Anaerobic Respiration than by Aerobic
Respiration.
Examples of anaerobic respiration
• Yeast converts sugars to alcohol in
“Fermentation” – this produces alcohol for
drinks such as beers and wine
Did you know ???s
When you get a cramp whilst exercising it is
caused by the acid that your cells produce when
they respire anaerobically (without oxygen).
• the only reason they do this is because your body
needs to produce so much energy while you
exercise that not enough oxygen reaches the cells
on time.
• To try to sort this out you start breathing fast and
get out of breath as your lungs are trying to take in
as much oxygen as possible!!
Now to test for Carbon Dioxide!
• Limewater turns cloudy in the presence of
Carbon Dioxide.
• What happened when you breathed into
limewater??
• What does this tell you??
Breathing
As you can see from the Equation Oxygen
and food are the two important things our
cells need to give us energy.
• We’ve learned how the food gets to our
cells by digestion.
• The oxygen gets to our cells by breathing!
Pharynx
This is the scientific name for your throat
area.
Trachea
This is the tube that leads into your lungs.
• It is very strong and is kept open by Rings
of Cartilage.
• If we didn’t have rings of cartilage what do
you think might happen??
Bronchus
As we have two lungs our Trachea divides
to branch into each one.
• These two branches are called Bronchi.
Bronchioles
To spread out through all our lungs the
bronchi break up to even smaller little
branches called BRONCHIOLES.
Alveoli
The final place the air we breathe in goes to
in our lung is the ALVEOLI.
It is in the Alveoli that Carbon Dioxide is
brought into the lungs to be exhaled and
oxygen is brought into the body for
respiration.
• This is called Gas excha
• It is in the Alveoli that Carbon Dioxide is
brought into the lungs to be exhaled and
oxygen is brought into the body for
respiration.
• This is called Gas exchange. Why do you
think it is called this?
