Understanding Ourselves

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Understanding Ourselves
(OCR)
W Richards The Weald School
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Body systems
The RESPIRATORY SYSTEM takes in _____
The ___________ SYSTEM transports oxygen and
glucose around the body
The SKELETAL and MUSCULAR systems use the _____
from glucose to allow ________
The DIGESTIVE SYSTEM takes in ________
Words energy, movement, oxygen, glucose,
circulatory
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Circulation
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The Circulatory system
The circulatory system is responsible for pumping
______ around the body. We need blood to be
taken around the body because blood contains
________ and _______. These are needed so that
all the ____ in our bodies can produce _____
through _________. Blood is pumped at high
pressure. Blood pressure is measured in mmHg
(millimetres of ______). Normal pressure is
about 120/80 mmHg.
Words energy, mercury, blood, glucose,
respiration, oxygen, cells
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High Blood Pressure
High blood pressure is a condition where the
______ and blood vessels experience extra strain.
It can be caused by

• Excess weight
• High stress levels
• _____
• Excess _______
• Diets that are high in saturated ___, sugar or
  salt

Long term high blood pressure can cause blood
vessels to weaken or even ______.
Words alcohol, burst, smoking, heart, fat
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(Aerobic) Respiration
Words breathing, energy, Mrs Gren, respiration,
food
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Anaerobic respiration
Unlike aerobic respiration, anaerobic respiration
is when energy is provided WITHOUT needing
_________
This happens when the body cant provide oxygen
quick enough for __________ respiration to take
place. Anaerobic respiration produces energy
much _______ than aerobic respiration but only
produces 1/20th as much. Lactic acid is also
produced, and this can build up in muscles
causing ______ and an oxygen ______. This
debt then needs to be repaid by deep
breathing to ________ the lactic acid.
Words debt, oxygen, fatigue, oxidise, aerobic,
quicker
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The Effect of Exercise
Heart rate/min
Breathing rate/min
100
225
Rest
Exercise
Recovery
75
175
50
125
25
75
5 mins
10 mins
15 mins
20 mins
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Balanced diet
A balanced diet should contain fats, proteins and
carbohydrates in roughly these amounts
It should also contain water, vitamins, minerals
and fibre.
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Modern diets and health problems
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Poor diets
If we dont have a balanced diet we may suffer
form a deficiency symptom
Vitamin D Protein Vitamin C Vitamin A Iron Calcium Anaemia Scurvy (bleeding gums and joints) Weak bones and teeth Wasting of body tissue Rickets Poor night vision
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Metabolic Rate and health

• The rate at which our bodies carry out chemical
  reactions is called the metabolic rate. This
  rate varies with
• The amount of work we do
• The amount of fat in our body
• Inherited factors

Condition How this affects our health
Lack of exercise Fatty diets Warm weather Using cars instead of walking Playing XBox instead of football
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Body-Mass Index
A commonly-used way to indicate is someone is
overweight or underweight is the Body Mass Index
(BMI)
BMI Meaning
lt18.5 Underweight
18.5-25 Ideal
25-30 Overweight
30-40 Obese
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Protein
Proteins are long chains of amino acids. There
are two main types of these

• Essential amino acids (must be eaten)
• Non-essential amino acids (can be made in the
  body)

People who do not eat enough protein will not
grow properly. Protein deficiency can result in
a disease called kwasiorkor, where the muscles
waste away and the belly swells.
How much protein should we eat?
RDA of protein (in g) 0.75 x body mass (in kg)
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Eating disorders
Anorexia nervosa this is a condition where
sufferers restrict what they eat and sometimes
starve themselves, leading to possible weight
loss, abdominal pains, discoloured skin,
irregular periods etc.
Bulimia nervosa this is when people vomit or
take laxatives straight after eating to get the
food out as quickly as possible. It can lead to
weight fluctuations, poor skin, hair loss,
irregular periods, tiredness etc.
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The digestive system
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.
Hydrochloric acid is produced in the stomach to
kill bacteria. Digestion also depends on
enzymes...
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Enzymes
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 ______
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
Bloodstream
Lipase (produced in the pancreas and small
intestine) breaks fats (_____) down into fatty
acids and glycerol
Words blood, lipids, proteins, digestion,
starch, smaller
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Bile and the liver

• Bile is a chemical produced in the liver and
  stored in the gall bladder. It has 2 functions
• It neutralises stomach acid and produces alkaline
  conditions for enzymes to work in
• It emulsifies (breaks down fats

Fat globules
Fat droplets
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Disease
A disease is any condition where the body does
not work properly. It can be caused by a number
of things

• A spread of infection from another person (an
  infectious disease, e.g. A cold)
• Poor diets (e.g. Scurvy)
• Organ malfunction (e.g. Diabetes)
• Genetic inheritance (e.g. Colour blindness)
• Mutations in cells (tumours, e.g. Cancer)
  these can be caused by smoking, drinking, too
  much sun etc

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Pathogens
Pathogens are microbes (micro organisms) that can
cause diseases. They can enter the body in a
number of ways
or other natural openings
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Disease
A disease is any condition where the body isnt
working as it should. This could be caused by a
malfunction in the body (as with diabetes) or it
could be caused by a type of pathogen
Viruses
Bacteria

• 1/1000th mm big
• Living cells (some are harmless)
• Grow very quickly
• Affected by antibiotics
• Examples food poisoning, tetanus, sore throats

• 1/1,000,000th mm big
• Genetic info inside a protein coat
• Not affected by antibiotics
• Release poisons
• Examples colds, flu, polio, chicken pox

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Using Antibiotics
Antibiotics can be used to kill bacteria.
However, there are two problems
1) Overuse of antibiotics can lead to bacteria
becoming resistant (e.g. the MRSA superbug).
This means that antibiotics must be used
sparingly. 2) Antibiotics have no effect on a
virus, like the common cold. It is difficult to
kill a virus without damaging body tissue. A
virus is usually allowed to run its course.
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Fungi
Fungi can also cause unwanted conditions. These
conditions can be treated with anti-fungal
medicine and antibiotics. Some examples (dont
look if youre faint hearted!)
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Transmitting Diseases
Pathogens can be transmitted in a number of ways

1. Horizontal transmission (directly ______ an ill
   person)
2. Vehicle transmission (touching an ill persons
   ________)
3. Vertical transmission (mother to ____)
4. Airborne (______ in the air)
5. Vector-borne (third party, e.g. __________)

Words mosquitoes, belongings, touching, baby,
germs
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Malaria
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Microbes our defence against them
Our bodies have defence mechanisms against
invading microbes
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Cleaning our air
Our respiratory system has two types of
specialised cell that help to keep our lungs
clean
1. Mucus is produced and traps dust, bacteria etc
2. The mucus is swept upwards to the mouth by
cilia (cells with tiny hairs)
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White blood cells
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
• They eat the microbe (these white blood cells are
  called phagocytes)
• They produce antibodies to neutralise the microbe
  (lymphocytes)
• The produce antitoxins to neutralise the poisons
  produced by microbes (lymphocytes again)

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Producing antibodies
Youre going down
Step 1 The lymphocyte sees the pathogen
(microbe)
Step 2 The cell produces antibodies to fit the
pathogen
Step 3 The antibodies fit onto the pathogens and
cause them to clump
Step 4 The pathogens are eaten by the white
blood cells
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Specific antibodies
Antibodies are specific they will neutralise
the microbe they have been made for.
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Fighting disease
NATURAL IMMUNITY
This is when antibodies are produced by a person
when needed or they are passed on by the mother
during pregnancy.
ARTIFICIAL IMMUNITY

• Can be done in two ways
• A vaccine with dead microbes is injected the
  body is tricked into producing antibodies ready
  for the real thing. This is called ACTIVE
  IMMUNISATION
• The antibodies are injected directly into the
  body this is called PASSIVE IMMUNISATION.

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Vaccinations
Some people argue that the MMR vaccine is a good
idea, others think it is a bad idea. Briefly
summarise each side of the argument
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Researching new medicines
Before new drugs can be approved they have to go
through three stages
3. Does it work? People with the illness are
tested on. This can involve using a placebo
a dummy pill
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The Nervous System
The CENTRAL NERVOUS SYSTEM (CNS) enables us to
react to our surroundings. It consists mainly of
the brain, the spinal chord, nerve cells
(neurones) and receptors.

• Types of receptor
• Light receptors in the eyes
• Sound receptors in the ears
• Taste receptors on the tongue
• Smell receptors in the nose
• Touch, pressure and temperature receptors in the
  skin
• Changes of position receptors in the ears
  (balance)

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Nervous Reactions
When we react to a stimulus our bodies use the
following pattern
For example, consider a man and a camel
Oh No!
What are the stimulus, receptor, coordinator,
effector and response in this situation?
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Examples of reactions
Stimulus Receptor (i.e. the thing that detects the stimulus) Effector (i.e. the thing that will do the reaction) Response (i.e. action taken)
Bright light
Sour taste
Losing balance
Sit on a drawing pin
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Types of nerve cell
Nerve cells (neurones) are elongated with
branched endings to connect to many muscles
fibres.
1) Motor neurone
2) Sensory neurone
3) Relay neurone
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Synapses
Neurones never ____ each other there is a small
gap between them called a _____. A signal is
sent from one _______ to the next by a _______
transmitter across the synapse. These
transmitters are then ________.
Words chemical, synapse, neurone, touch,
destroyed
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Conscious actions
A conscious action is one where the brain makes a
considered response. Heres what happens
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Reflex actions
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. Heres how
it works
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Reflex actions
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Vision
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The Eye
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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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Focussing on different distances
For distant objects the ciliary muscles relax and
the suspensory ligaments pull tight making the
lens pull thin the light doesnt bend as much.
For close objects the ciliary muscles contract
allowing the lens to go fat, thus bending the
light more.
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The Iris Reflex
When the light is bright the radial muscles
relax, the circular muscles contract and the
pupil increases in size.
When the light is bright the radial muscles
_____, the circular muscles _______ and the pupil
________ in size.
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Drugs Research Project
Explain and give examples for the following

1. Why do people use legal drugs?
2. What are the drawbacks of legal drugs?
3. Alchohol is a legal drug. What does it do to
   the human body?
4. Why do people use illegal drugs?
5. What are the drawbacks of illegal drugs? What
   can they cause?
6. Find out which drugs are in which classes

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Drugs
Drug Effect on nerves Effect on activities Abnormal behaviour caused
Caffeine/ other stimulants
Barbiturates/ other sedatives
Paracetamol/ other painkillers
Speed up synapse transmissions
Reactions could become faster
Highly strung, leads to exhaustion
Slow down synapse transmissions
May make you drowsy, you shouldnt drive
Highly addictive, make you irritable
Prevent synapse transmissions
May make you drowsy, you shouldnt drive
Side effects include dizziness or itchiness
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Smoking

• Cigarettes contain 3 harmful things
• NICOTINE, which is an ___________ drug that
  raises the heart beat, narrows the arteries and
  so causes ____ _____ _____. This leads to heart
  _________.
• TAR, which coats the lining of the _______ making
  them less able to take in oxygen. It also
  contains carcinogens which cause ______________.
• CARBON MONOXIDE, which is a _______ ____ which
  joins up with ____ blood cells making them
  incapable of transporting _____________ around
  the body. In pregnant women it can cause oxygen
  deprivation, leading to low birth ______.

Words high blood pressure, oxygen, red,
addictive, disease, poisonous gas, lungs, cancer,
mass
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Homeostasis
Homeostasis means controlling internal
conditions
Waste products that need to be removed how Waste products that need to be removed how
CO2
Urea

Internal conditions that need controlling how Internal conditions that need controlling how
Temperature
Ion content
Water content
Blood glucose
Produced by respiration, removed via lungs
Produced by liver breaking down amino acids,
removed by kidneys and transferred to bladder
Increased by shivering, lost by sweating
Increased by eating, lost by sweating urine
Increased by drinking, lost by sweating urine
Increased and decreased by hormones
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Maintaining Body Temperature
Cold
Hot
Vasoconstriction
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Hormones
Hormones are chemical messengers produced by
endocrine _____. They control the way in which
parts of the body work and are transported to
their target organs in the _______. Some
examples...

• The pancreas produces _______
• The adrenal gland produce ________
• The pituitary gland produces FSH and LH
• Testes produce __________
• Ovaries produce progesterone

Words testosterone, glands, bloodstream,
insulin, adrenaline
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Controlling Blood Sugar levels
We need glucose in our bodies to help our cells
to respire and produce energy. What happens if
we have too much glucose?
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Diabetes
Diabetes is a ________ in which a persons blood
sugar (i.e. glucose) level may rise to a _______
level. This is because the ______ doesnt
produce enough _________. Diabetes can be
treated by __________ carefully or by injecting
extra insulin when needed. Diabetics have to
test their blood sugar level before they decide
how much insulin to _______ themselves with.
Words insulin, disease, inject, dangerous,
eating, pancreas
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The Menstrual Cycle
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Fertility
The amount of glucose in our blood is an example
of a process controlled by hormones. Hormones
are chemical messengers, produced by glands and
tranposrted by blood. Another example of a
process controlled by hormones is the menstrual
cycle, where hormones can...

1. stimulate the release of eggs
2. inhibit the release of eggs

In normal circumstances natural hormones are
responsible for releasing the egg and for
thickening the lining of the womb. These
hormones are produced by the pituitary gland in
the brain and in the ovaries.
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Genes, Chromosomes and DNA
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How genes work
Some facts - Made up of paired bases A links
with T and C links with G to form a double
helix - Contain instructions on what a cell
does, how the organism should work etc - The
instructions are in the form of a code - The
code is made up from the four bases that hold the
strands together - The bases represent the order
in which amino acids are assembled to make
proteins - Only some of the genes in each cell
are switched on - DNA can be mutated by
X-rays, UV, certain chemicals etc
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Sexual Reproduction
We have similar characteristics to our parents
due to genetic information being passed down in
genes through gametes
The human egg and sperm cell (GAMETES) contain
23 chromosomes each.
When fertilisation happens the gametes fuse
together to make a single cell called a ZYGOTE.
The zygote has 46 chromosomes (23 pairs) and
contains information from each parent.
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Sexual vs. Asexual reproduction

• Sexual reproduction
• 2 parents are needed
• Offspring will have pairs of chromosomes
• This will cause genetic variation
• Asexual reproduction
• Only 1 parent needed
• Offspring are GENETICALLY IDENTICAL to parent
  (clones)

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Boy or Girl?
Girl
Boy
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Boy or Girl?
Mother
Son
Father
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Eye colour
In eye colour the brown eye allele is dominant,
so we call it B, and the blue eye is recessive,
so we call it b
bb
BB
Bb
Homozygous brown-eyed parent
Heterozygous brown-eyed parent
Blue-eyed parent
What would the offspring have?
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Eye colour
Example 1 A homozygous brown-eyed parent and a
blue-eyed parent
Example 2 2 heterozygous brown-eyed parents
X
X
Parents
Gametes
(FOIL)
Offspring
All offspring have brown eyes
25 chance of blue eyes
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Eye colour
Example 3 A heterozygous brown-eyed father and a
blue-eyed mother
Equal (50) chance of being either brown eyed or
blue eyed.
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Another method
Example 3 A heterozygous brown-eyed father and a
blue-eyed mother
B b
b
b
B b
b Bb bb
b Bb bb
Father
Mother
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Example questions
1) In mice, white fur is dominant. What type of
offspring would you expect from a cross between a
heterozygous individual and one with grey fur?
Explain your answer with a genetic diagram.
2) A homozygous long-tailed cat is crossed with
a homozygous short-tailed cat and produces a
litter of 9 long-tailed kittens. Show the
probable offspring which would be produced if two
of these kittens were mated and describe the
characteristics of the offspring (hint work out
the kittens genotype first).
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Inherited diseases
1) Cystic fibrosis a disease that causes thick
and sticky mucus to coat the lungs, gut and
pancreas. Its caused by recessive alleles
2) Huntingdon's disease a disease of the
nervous system that causes shaking and eventually
dementia. Its caused by a dominant allele
3) Sickle cell anaemia a disease that alters
the shape of red blood cells, thereby reducing
their oxygen capacity, causing weakness and
anaemia. Its caused by recessive alleles
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Key words
Gamete Zygote Allele Dominant Recessive Homoz
ygous Heterozygous

• This allele determines the development of a
  characteristic
• This is formed when an egg is fertilised by a
  sperm
• This allele will determine a characteristic only
  if there are no dominant ones
• This word refers to a pair of chromosomes being
  made of two different alleles of a gene
• An egg or a sperm are called this
• This word refers to a pair of chromosomes being
  made of two of the same alleles of a gene
• An alternative form of a gene