Transcript Humans as Organisms

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The Human Body Action and Control
Some systems in the human body
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Respiratory system
Circulatory
system
Digestive
system
Muscular system
Skeletal system
The digestive system
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The whole point of digestion is to break down our food so
that we can get the bits we need from it…
The main foods
affected are
CARBOHYDRATES –
these are broken down
into GLUCOSE
The small intestine
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This is where the “small parts” are absorbed into our blood
stream…
Everything else
passes into the
large intestine
Glucose gets
absorbed into
the blood
Enzymes
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Carbohydrase (produced in the mouth,
pancreas and small intestine) breaks
_______ (a carbohydrate) down into
glucose:
Protease (produced in the stomach,
pancreas and small intestine) breaks
_______ down into amino acids:
Lipase (produced in the pancreas and
small intestine) breaks fats (_____)
down into fatty acids and glycerol:
Words – blood, lipids, proteins, digestion, starch, smaller
Bloodstream
Enzymes are chemicals produced by the body to help
_______. When they react with food they break it down
into ______ pieces which can then pass into the ______:
Method:
The Model Intestine
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1)
Put some water into two boiling tubes and test the water for starch and
glucose
2)
Place the starch into the visking tube bag, add some enzyme and wash the
outside
3)
Place some starch WITHOUT enzyme in another visking tube bag
4)
Place both visking tubes into the separate boiling tubes and start the stopclock
5)
Test the water around the visking tubes for starch and glucose every two
minutes
6)
After ten minutes test the water one last time and then test the solutions in
the visking tube bag
1) Why did the starch stay inside the visking tube?
2) What difference did adding the enzyme make? What did it do to
the starch?
3) Where did the glucose go?
Bile and the liver
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Bile is a chemical produced in the
liver and stored in the gall
bladder. It has 2 functions:
1) It neutralises stomach acid
and produces alkaline
conditions for enzymes to
work in
2) It emulsifies (“breaks down”
fats:
Fat
globules
Fat
droplets
Arteries, veins and capillaries
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Arteries carry high pressure
blood away from the heart.
They have smaller lumen and
no valves.
Capillaries have thin walls
(one cell thick) to allow
glucose and oxygen to pass
through. Also used to
connect arteries to veins.
“Lumen”
Veins carry low pressure blood back to the
heart. They have thinner, less elastic walls and
have valves to prevent backflow of blood.
The four parts of blood
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1. RED BLOOD CELLS – contain haemoglobin
and carry ______ around the body. They
have no _______ and a large surface area.
2. PLATELETS – small bits of cells that lie
around waiting for a cut to happen so that
they can ____ (for a scab).
3. WHITE BLOOD CELLS – kill invading
_______ by producing _________ or
engulfing (“eating”) the microbe.
These three are all carried around by the
PLASMA (a straw-coloured liquid). Plasma
transports CO2 and ______ as well as
taking away waste products to the ______.
Words – antibodies, clot, kidneys,
oxygen, nucleus, glucose, microbes.
Fighting disease
If microbes enter our body they need to be
neutralised or killed. This is done by
WHITE BLOOD CELLS:
White blood cells do 3 things:
1) They eat the microbe
2) They produce antibodies to
neutralise the microbe
3) The produce antitoxins to
neutralise the poisons produced
by microbes
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Producing antibodies
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You’re going
down
Step 1: The white blood cell “sees”
the antigen (microbe)
Step 2: The cell produces
antibodies to “fit” the antigen
Step 3: The antibodies fit onto the
antigens and cause them to “clump”
Step 4: The antigens are “eaten”
by the white blood cells
The Nervous System
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The NERVOUS SYSTEM consists mainly of the brain, the
spinal chord, nerve cells (“neurones”) and receptors.
Types of receptor:
1) Light receptors in the eyes
2) Sound receptors in the ears
3) Taste receptors on the tongue
4) Smell receptors in the nose
5) Touch, pressure and temperature receptors in the skin
6) Changes of position receptors in the ears (balance)
Stimulus
Receptor
Coordinator
Effector
Response
Examples of reactions
Stimulus
Bright light
Sour taste
Losing balance
Sit on a drawing pin
Receptor
(i.e. the thing that
detects the stimulus)
Effector
(i.e. the thing that
will do the reaction)
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Response
(i.e. action taken)
Types of nerve cell
Nucleus
Cell body
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Muscle strands
(effector)
Nerve cells (neurones) are elongated with branched
endings to connect to many muscles fibres.
1) Motor neurone
2) Sensory neurone
Impulse
Impulse
3) Relay neurone
Conscious actions
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A conscious action is one where the brain makes a considered response.
Here’s what happens:
4) The brain
3) Here another sensory neurone
decides to move
carries the signal to the brain
away the hand
5) This impulse is
sent by MOTOR
NEURONES to the
hand muscles (the
effectors) via the
spinal chord…
2) The impulse is carried
by SENSORY NEURONES
to the spinal chord
1) Receptors in
your skin detect
a stimulus
Stimulus
6) Which then
moves the hand
away
Receptor
Motor Neurone
Sensory Neurone
Effector
Coordinator
Response
Reflex actions
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Sometimes conscious action is too slow to prevent harm, e.g…
In situations like this
the body bypasses the
brain to produce a
quicker response.
Here’s how it works…
Reflex actions
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Synapses
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Neurones never touch each other – there is a small gap
between them called a SYNAPSE. A signal is sent from one
neurone to the next by a chemical transmitter across the
synapse. These transmitters are then destroyed.
The Iris Reflex
When the light is bright
the radial muscles relax,
the circular muscles
contract and the pupil
increases in size.
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When the light is bright
the radial muscles _____,
the circular muscles
_______ and the pupil
________ in size.
The Eye
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The Eye
Iris
Lens
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Sclera
Retina
Pupil
Optic
nerve
Cornea
Ciliary muscles
Suspensory
ligaments
Seeing things
Rays of light are refracted
(bent) first by the cornea
and then by the lens. They
focus on the retina.
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Seeing things at different distances
For distant objects the
ciliary muscles relax
and the suspensory
ligaments pull tight
making the lens pull
thin – the light doesn’t
bend as much.
For close objects the
ciliary muscles contract
allowing the lens to go
fat, thus bending the
light more.
Smoking, drugs and alcohol
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Smoking
Drugs
Alcohol
Smoking
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Cigarettes contain 3 harmful things:
1. NICOTINE, which is an ___________ drug that raises
the heart beat, narrows the arteries and so causes
____ _____ _____. This leads to heart _________.
2. TAR, which coats the lining of the _______ making
them less able to take in oxygen. It also contains
carcinogens which cause ______________.
3. CARBON MONOXIDE, which is a _______ ____ which
joins up with ____ blood cells making them incapable of
transporting _____________ around the body.
Words – high blood pressure, oxygen, red, addictive,
disease, poisonous gas, lungs, cancer
Damaging the alveoli (emphysema)
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Before smoking
After smoking – less
surface area
Homeostasis
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Homeostasis means “controlling internal conditions”:
Waste products that need to be removed + how
CO2
Produced by respiration, removed via lungs
Urea
Produced by liver breaking down amino acids,
removed by kidneys and transferred to bladder
Internal conditions that need controlling + how
Temperature
Increased by shivering, lost by sweating
Ion content
Increased by eating, lost by sweating + urine
Water content
Increased by drinking, lost by sweating + urine
Blood glucose
Increased and decreased by hormones
Kidneys
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Kidneys are responsible for controlling ion, urea and
water content.
Blood in
Kidneys are made up of two
important tissues – BLOOD
VESSELS and TUBULES.
Blood out
Ureter (tube that takes
urine down to bladder)
Kidneys
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Kidneys work in 3 stages:
Blood vessel
1. ULTRAFILTRATION - Lots of water and
products of digestion are squeezed out of
the blood and into tubules under pressure.
2. SELECTIVE REABSORPTION – the blood
takes back the things it wants (e.g. glucose
and ions) even though this means going
against a concentration gradient.
3. WASTE – excess water, excess ions and
any urea are now removed through the
ureter
Tubule
Kidney structure
1) Ultrafiltration
2) Selective
reabsorption
3) Excretion
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Controlling water content
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The amount of water reabsorbed into the blood vessels in
the kidney is controlled by the hormone ADH:
The Skin
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Controlling body temperature
Body temperature is controlled by the thermo-regulatory centre in the
________. It is kept at 370C as this is the best temperature for
__________ to work in. If the body becomes too hot then blood
vessels _________ and sweat glands release ________. If the body is
too ______ then blood vessels constrict and muscles start to
__________.
Words – sweat, enzymes, cold, dilate, shiver, brain