High blood pressure: -
Blood vessels burst -
damage to brain (stroke)
- damage kidneys
Can be increased by stress, alcohol,
smoking, being overweight
Can be decreased by regular exercise and a
balanced diet
Blood pressure is measured in mm of mercury
(mmHg)
Systolic Pressure; maximum pressure the heart
produces
Diastolic pressure; the pressure between
heart beats
Fitness is the ability to do
physical activity
Can be measured by Strength, Flexibility, Stamina,
Agility, Speed
Health is being free from diseases
Smoking
Carbon Monoxide in cigarette smoke decreases the oxygen-carrying
capacity of blood as it combines with haemoglobin, preventing it from
combining with oxygen so less is carried.
Heart disease is caused by a restricted
blood flow to the heart muscle.
Increased by: high levels of saturated fat, which
leads to building up cholestrol
Narrowing of arteries
caused by plaques in
the coronary arteries
can reduce blood flow
to the heart muscle. Also
makes blood clots or
thrombosis, which will
also block the artery.
Human Health and Diet
Carbohydrates- Simple sugars such as
glucose
Stored in the liver as glycogen/converted into fats.
Proteins- Amino acids
Can't be stored in the body but are
used to repair and for growth
EAR in g = 0.6 x body mass in kg
Depends on certain factors; body mass, age,
pregnancy or breast feeding,
Too little protein can
cause Kwashiorkor which
is popular in LEDC'S due
to lack of money to buy
food.
First class proteins
- Meat and Fish.
Contain Amino
Acids which can't
be made by the
human body.
Second class
proteins - Plants
proteins. Don't
include all of the
Amino Acids.
Fats-Fatty acids and glycerol
Stored under the skin/around organs.
Balanced diet varies according to
specific factors. Whether its your age,
gender, level of activity, religion,
vegetarian/vegan, or medical
issues/food allergies
BMI = mass in kg / (height in m)2
More than 30:Obese. 25-30:Overweight
20-25:Normal. Less than 20:
Underweight
Staying Healthy
Malaria
Caused by protozoan called
Plasmodium(parasites), which feeds on human red
blood cells.
Mosquito- Carries Plasmodium and is the vector,
where as us humans are the host. It releases the
Plasmodium into our bodies, which travels to our lungs
and bursts our red blood cells.
Treatments - draining stagnant water,
putting oil on it's surface and spraying
insecticide to stop the mosquitoes life
cycle
Cancer
not smoking - prevents
risk of skin cancer
Wearing suncream-
prevents risk of skin
cancer
Benign tumour cells (in
warts) divide slowly and are
harmless
Cancers are malignant
tumours; the cells have
uncontrolled growth and
may spread
Pathogens(cause diseases)
destroy the body cells or
produce poisionous cells
called Toxins.
The body protects itself by producing antibodies
from the white blood cells resulting in active
immunity
The antibodies protect us by locking onto
antigens which are on the surface of Pathogens
and kills them
Each Pathogen has it's own Anitbody
Vaccinations
Injecting a harmless
pathogen which is carrying
antigens. The antigens
trigger the white blood
cells which then sends out
correct antibodies.
Memory Cells
(T-lymphocyte cell) remain
in the body which provides
immunity against that
disease.
Tested on
animals, human
tissue and
computers
beforehand
An antiviral drug slows down the Pathogens development
Trials
Blind trial, the patient
doesn't know whether
they're receiving a drug
or a placebo. Avoid a
'feel- good factor' and a
biased opinion.
The nervous system
How do eyes work?
Light rays are refracted (bent) by the cornea and the lens.
Binocular vision helps to judge
distance by comparing the
images from each eye, the
more different that they are, the
nearer that the object is.
Accommodation -
Focusing light from
distant or near objects
by altering the shape of
the lens.
When focusing on distant objects, the
ciliary muscles relax and the
suspensory ligaments tighten so the
lens has a less rounded shape.
Vise-versa for focusing on near objects.
Faults in vision
Red- green colour
blindness is caused
by a lack of
specialised cells in
the retina
Long sight - the eyeball is too
short or the lens is too thin, so
the image is focused behind the
retina
Convex lens
Short sight - the
eyeball is too long
or the lens is too
rounded so the
lens refracts light
too much so the
image would be
infront of the retina
Concave lens
Nerve Cells
Nerve cells are
called neurones.
Nerve impulses
pass along the
axon.
Reflex action is show by a reflex
arc. Stimulus-Receptor-Sensory
Neurone-Central Nervous
System-Motor
Neurone-Effector-Respone
Block the transmission of nerve
impulses across synapses by
binding with receptor molecules in
the membrane of the receiving
neurone.
Painkillers- Aspirin, Paracetamol
Stimulants- Nicotine, Ecstasy, Caffeine
Cause more
neurotransmitter
substances to
cross synapses.
Performance enhancers- Anabolic steroids
Hallucinogens- LSD
Effects of smoking
Smoke contains many
chemicals that stop cilia
moving.
Cilia-tiny hairs
found in
epithelial lining
of trachea,
bronchi and
bronchioles
Smokers cough- dust and
particulates in smoke irritating the
epithelial lining and mucus not
being moved by the cilia.
Effects of alcohol
Increases
reaction
times and
risk of
accidents
Cirrhosis of the
Liver- Liver is
damaged when
it breaks down
toxic chemicals
such as alcohol.
Staying in balance
Homeostasis
Definition- Keeping a
constant internal
environment
Involves balancing bodily inputs and outputs
Automatic control system keeps the
levels of temperature, water and carbon
dioxide steady
Negative feedback controls are
used in it. Act to cancel out a
change such as decreasing
temperature level.
Temperature control
Normal body temp: 37 degrees celscius
High temp can cause: heat stroke, dehydration
Low temp can cause: hypothermia
Blood temp is monitored by the hypothalamus
gland in the brain. Reaction to temp extremes
are controlled by the nervous/hormonal
systemss which trigger
vasoconstriction/vasodilation
Vasoconstriction -
Narrowing of small blood
vessels in skin. Causes
less blood flow/less heat
transfer.
Vasodilation- widening of small blood vessels in skin.
Causes more blood flow near the skin surface resulting in
more heat transfer
Control of blood sugar levels
Insulin- hormone, control blood sugar levels
Converts excess glucose in the blood into glycogen, stored in liver
Type 1 diabetes- Pancreas not producing
any insulin, must be treated by insulin
Insulin varies
according to the
persons
diet/activity. Big
effort of exercise
needs more glucose
to be in the blood,
so lower insulin is
then required.
Type 2 diabetes- Body producing little
insulin or body not reacting it, can be
controlled by diet
Controlling plant growth
Plant responses
Phototropism - a plant's growth response to light.
Geotropism - a plant's growth response to gravity.
Shoots are positively phototropic and grow
towards the light, and are also geotropic as
they grow away from the pull of gravity.
Roots are negatively phototropic and positively geotropic.
Plant hormones (auxins)
Auxins- group of plant hormones, more through the plant in solution
They are involved in phototropism and geotropism
Different amounts
of auxins are found
in different parts of
the shoot when the
tip is exposed to
light. Auxin is
mostly found in the
shady parts of the
shoots.
Higher amount of
auxin = increased
length of cells
Therefore,
an
increased
amount of
cell length
on the
shady side
causes for
the shoot to
curve
towards the
light
If tip is removed, will not grow
Uses
Used as a selective weed killer, which kill
specific weeds and increase the crop yield
Root powder to increase root growth of cuttings
Delay fruit ripening to meet market demands
Control dormancy in seeds
Variation and inheritance
Inherited characteristics
Inherited characteristics can be dominant or recessive
They depend on dominant and recessive alleles
Dominant alleles- expressed when
present
Recessive alleles- only in the absence of the
dominant allele.
Alleles- different versions of the same gene
Chromosomes
Human cells have 23 pairs.
Female - XX
Eggs only carry X chromosomes
Male - XY
Sperm carries either X or Y chromosomes
Random chance - equal chance of the offspring being male or female
Genetic variation
Caused by
Mutations -
random changes
in the genes or
chromosomes
Rearrangements of genes during the formation of gametes
Fertilisation - zygote
with alleles from father
and mother
Monohybrid cross
Involves 1 pair of
characteristics
controlled by a
single gene, one
allele being
dominant and the
other being
recessive
Homozygous - identical alleles
Heterozygous- having different alleles
Genotype - genetic make up
Phentoype - alleles are expressed
Inherited disorders
Caused by faulty alleles, mostly recessive
Possible to
predict the
probability of
inheriting such
disorders by
interpreting
genetic
diagrams.