Transcript - SlideBoom

Mr. Lajos Papp
The British International School, Budapest
2014/2015
Levels of organisation
Describe the levels of organisation within
organisms
Organelle: a specialized part of a cell that has its own
function, e.g. the nucleus, chloroplast.
Cell: the smallest part of a living structure that can
operate as an independent unit , e.g. liver cell, nerve
cell.
Tissue: a group of cells with similar structures, working
together to perform a shared function, e.g. nerve tissue.
Organ: a structure made up of a group of tissues,
working together to perform specific functions, e.g.
liver, kidney.
(Organ) System: a group of organs with related
functions, working together to perform body functions,
e.g. digestive system.
Cell structure
Describe cell structures, including
nucleus
cytoplasm
cell membrane
cell wall
chloroplast
vacuole
Describe the functions of
nucleus: contains the genetic material. This carries the
coded instructions for controlling the activities and
characteristics of the cell.
cytoplasm: contains water and dissolved substances
such as sugars and salts.
cell membrane: a membrane that controls the entry and
exit of dissolved substances and separates the cell’s
contents from its surroundings.
cell wall: provides structural support, permeable for
dissolved substances and water and prevents damage i.e.
cell can’t explode.
chloroplast:
necessary
for
photosynthesis.
contains
the
chlorophyll
production
and
of
enzymes
glucose
by
vacuole: contains water necessary to provide turgor
pressure and may store ions and molecules.
Staining and observing onion epidermis
Compare two different stains
Viewing pondweed leaves with a microscope
Compare the structures of plant and animal
cells
Cell organelles found in both types of cells
Cell organelles found only in plant cells
http://www.bbc.co.uk/learningzone/clips/parts-of-plantand-animal-cells/10602.html
http://www.youtube.com/watch?v=hn2n2swnLLI
http://www.dnatube.com/video/3990/Ruch-rotacyjny-
cytoplazmy-w-komorkach-Elodea-canadensis
Biological molecules
Identify
the
chemical
elements
present
carbohydrates, proteins and lipids (fats and oils)
Carbohydrates: carbon, hydrogen, oxygen.
Proteins: carbon, hydrogen, oxygen, nitrogen.
Lipids: carbon, hydrogen, oxygen.
in
Describe the structure of carbohydrates, proteins
and lipids as large molecules made up from smaller
basic units.
monomer
polymer
simple sugar (glucose)
starch (plant), glycogen (animal)
fatty acids, glycerol
fats (animals), oils (plants)
amino acid
protein
http://www.webpages.uidaho.edu/bionet/biol115/t2_basi
cs_of_life/flash/T2L2M4_activity_carbonhydrate.htm
Describe the tests for glucose and starch.
Practical.
Understand the roles of enzymes as biological
catalysts in metabolic reactions.
Enzymes are proteins that act as biological catalysts
controlling the rate of chemical reactions in living
organisms.
Enzymes help chemical substances change into new
substances.
Enzymes are specific, which means that each enzyme
only works on one substance.
Enzymes are produced by cells.
Enzymes work best at a particular temperature, called
their optimum temperature. At temperatures that are
too high the structure of an enzyme will be changed so
that it will not work. This is irreversible and the enzyme
is said to be denatured.
Enzymes work best at a particular pH, called their
optimum pH. Extremes of pH can denature enzymes.
http://highered.mcgrawhill.com/sites/0072943696/student_view0/chapter2/ani
mation__how_enzymes_work.html
http://www.dnatube.com/video/4999/Enzyme-Animation
http://www.youtube.com/watch?v=feik6wOXFA0&list=PL
B18E7605870F23C9
Understand how the functioning of enzymes can be
affected by changes in temperature, including those
due to change in active site.
Worksheets, plotting graphs.
http://highered.mcgraw-
hill.com/sites/0072943696/student_view0/chapter2/ani
mation__protein_denaturation.html
Temperature
enzymes
have
an
optimum
temperature:
the
temperature at which they work best giving the fastest
reaction. Graph.
When temperature increases, the molecules move faster
so collide with an enzyme in less time, having more
energy makes them more likely to bind to the active
site: the part of an enzyme where a specific substrate
will fit perfectly.
If the temperature is too high, the enzyme molecules
vibrate too vigorously and the enzyme is denatured: it
loses its 3D shape and will no longer bind with a
substrate. When the temperature is too low there is not
enough kinetic energy for the reaction so it reacts too
slowly.
Describe experiments to investigate how enzyme
activity can be affected by changes in temperature.
Practicals:
 starch - amylase
 lipids - lipase
Movement of substances into and out of cells
Understand definitions of diffusion, osmosis and
active transport.
Diffusion
the net movement of molecules from a region of higher
concentration to a region of lower concentration down a
concentration gradient, as a result of their random
movement.
Examples: oxygen entering red blood cells, carbon
dioxide entering leaf cells.
http://www.youtube.com/watch?v=VY0mZUDvbH4
Osmosis
the diffusion of water molecules from a region of low
solute concentration (high concentration of water
molecules) to a region of higher solute concentration
(low concentration of water molecules), through a
partially permeable membrane.
Examples: water entering the roots of plants.
http://www.youtube.com/watch?v=w3_8FSrqc-I
Active transport
movement of ions in or out of a cell through the cell
membrane, from a region of lower concentration to a
region of higher concentration against a concentration
gradient, using a channel protein and energy
released during respiration.
Understand that movement of substances into and
out of cells can be by diffusion, osmosis and active
transport.
http://www.youtube.com/watch?v=ThLPtmZdgPg
Understand the factors that affect the rate of
movement of substances into and out of cells:
the effects of surface area to volume ratio,
temperature,
concentration gradient.
Understand the effects of surface area to volume ratio
The larger the surface area to volume ratio the more rapidly
materials can pass into the body. Living organisms with large
volumes make use of it by having organs with extremely large
surface areas (lungs or gills) to exchange gases with the
environment.
Potato experiment.
Understand temperature
The higher the temperature, the faster the particles
move, higher rate of diffusion and osmosis.
Diffusion in cold and hot water experiment.
Understand concentration gradient
The higher the concentration gradient, the higher the
rate of diffusion and osmosis is.
Visking tubing experiment.
Describe experiments to investigate diffusion and
osmosis using living and non-living systems.
living
non - living
Diffusion
gases in lungs or
leaf
dye particles in
water
Osmosis
red blood cells,
potato chips
visking tube with
glucose
Nutrition
Flowering plants
Describe
the
process
of
photosynthesis
and
understand its importance in the conversion of light
energy to chemical energy.
Solar energy is converted into chemical energy by
chlorophylls (pigments found in a plant cell organelle
named chloroplast). Energy enters into an ecosystem.
Write the word equation and the balanced chemical
symbol equation for photosynthesis.
carbon dioxide + water →
6 CO2
+
6 H2O →
Testing leaves for starch.
glucose +
oxygen
C6H12O6 + 6 O2
During photosynthesis plants form starch grains in the
chloroplasts. Destarching a plant involves preventing
photosynthesis, usually by keeping the plant in the dark
for 24 to 48 hours until the starch is used by the plant
for energy.
Leaves are often tested for starch using iodine. The leaf
must first be boiled in alcohol to remove chlorophyll
and cuticle. Be careful when boiling alcohol because it
is a fire hazard.
Understand
how
varying
carbon
dioxide
concentration, light intensity and temperature affect
the rate of photosynthesis.
Positive correlation, limiting factors.
Simulations, graphs, plannings.
http://www.kscience.co.uk/animations/photolab.htm
http://www.syngenta.com/country/uk/en/learningzone/KS345/biology/Pages/Photosynthesis_in_Action.as
px
http://www.saddleworth.oldham.sch.uk/science/simula
tions/waterweed.htm
Describe the structure of a leaf and explain how it is
adapted for photosynthesis.
Handout, labelling, adaptations.
Adaption
Large surface area
Thin
Purpose
To absorb more light
Short distance for carbon dioxide
to diffuse into leaf cells
Chlorophyll
Absorbs
sunlight
to
transfer
energy into chemicals
Network of veins
To support the leaf and transport
water and carbohydrates
Stomata
Allow carbon dioxide to diffuse
into the leaf
Adaption
Purpose
To allow more light to reach the
Epidermis is thin and transparent
palisade cells
Thin cuticle made of wax
To protect the
blocking out light
leaf
Palisade cell layer at top of leaf
To absorb more light
without
Air spaces allow carbon dioxide
Spongy layer
to diffuse through the leaf, and
increase the surface area
Palisade cells contain many
chloroplasts
To absorb all the available light
Understand that plants require mineral ions for
growth and that magnesium ions are needed for
chlorophyll and nitrate ions are needed for amino
acids.
Describe experiments to investigate photosynthesis,
showing the evolution of oxygen from a water plant,
the production of starch and the requirements of
light, carbon dioxide and chlorophyll.
Humans
Identify
sources
and
describe
functions
of
carbohydrate, protein, lipid (fats and oils), vitamins
A, C and D, the mineral ions calcium and iron, water
and dietary fibre as components of the diet.
nutrient
source
cane sugar, rice, potatoes, wheat, sweets,
carbohydrate
soft drinks
poultry, fish and sea food, meat, dry beans
protein
lipid
vitamin A
and nuts, lentils
cocoa, coconut, nut oil, fish oil, meat, milk,
eggs
spinach,
carrots,
squash,
pumpkin,
cantaloupe, apricots, liver, milk, whole eggs
nutrient
source
citrus
vitamin C
fruits,
cabbage,
sprouts,
cauliflower, pineapple, strawberries
and green and red peppers
vitamin D
milk, fish oil and eggs
calcium ion
milk, cheese and fish
nutrient
source
red meat, dark green vegetables
iron ion
e.g. spinach and parsley, and liver
drinks, foods (especially salad
water
foods
like
tomatoes),
respiration
fibre
bread, pasta, cereals
aerobic
nutrient
function
fuel
carbohydrate
for
cellular
respiration,
component of important molecules
enzymes, growth, repair of tissues,
protein
immunity, vision, movement
component
lipid
of
membranes,
insulation, protection of organs,
energy storage
vitamin A
cell
vision
nutrient
function
to make skin, tendons, ligaments, and
blood vessels,
vitamin C
heals wounds and forms scar tissue,
repairs and maintains cartilage, bones
and teeth
vitamin D
helps bones absorb calcium
calcium ion
teeth, bones, blood clotting
nutrient
iron ion
function
haemoglobin
solvent, reactant, body temperature
water
regulation
fibre
helps digestion
Describe the structures of the human alimentary
canal and describe the functions of the mouth,
oesophagus, stomach, small intestine, large intestine
and pancreas.
part
structure
mouth
teeth, salivary glands, tongue
oesophagus
muscular tube
stomach
muscular wall (sack), cells in the wall
small intestine
muscular
tube,
infoldings,
(muscular movement)
peristalsis
part
large intestine
pancreas
structure
muscular tube, infoldings, peristalsis
(muscular movement)
located below the stomach
part
mouth
function
mechanical, chemical digestion, bolus
formation
oesophagus
swallowing
stomach
mechanical digestion, protein digestion
small intestine
completes
nutrients
digestion,
absorption
of
part
large intestine
pancreas
function
absorbs water, minerals
produces digestive enzymes, regulatory
hormones
Understand the processes of ingestion, digestion,
absorption, assimilation and egestion.
ingestion: take food into the body by the mouth for
digestion or absorption.
digestion: the process by which food is converted into
substances that can be absorbed and assimilated by the
body. It is accomplished in the alimentary canal by the
mechanical
(physical)
and
enzymatic
(chemical)
breakdown of foods into simpler chemical compounds.
absorption: the process of absorbing substances into
cells or across the tissues and organs through diffusion
or osmosis.
assimilation: The conversion of nutriment into a
useable form that is incorporated into the tissues and
organs.
egestion: the discharge or expulsion of undigested
material (food) from the digestive tract via the anus.
Explain how and why food is moved through the gut
by peristalsis.
http://www.bbc.co.uk/schools/gcsebitesize/science/ad
d_edexcel/common_systems/digestionrev1.shtml
https://www.youtube.com/watch?v=YJ34Qx6hzJk
https://www.youtube.com/watch?v=rJS-
Kh5wCQU&list=PLLs8TGOI7tWMynSz_LN2igSkx
ZZ9oMJ0L
https://www.youtube.com/watch?v=ZZCgF24HI_o
Understand the role of digestive enzymes, to include
the digestion of starch to glucose by amylase and
maltase, the digestion of proteins to amino acids by
proteases and the digestion of lipids to fatty acids
and glycerol by lipases.
Understand that bile is produced by the liver and
stored in the gall bladder, and understand the role of
bile in neutralising stomach acid and emulsifying
lipids.
Demonstration.
Describe the structure of a villus and explain how
this helps absorption of the products of digestion in
the small intestine.
Respiration
Understand that the process of respiration releases
energy in living organisms.
Describe the differences between aerobic and
anaerobic respiration.
https://www.youtube.com/watch?v=W9akfo7JHMQ
#t=37
Aerobic
respiration
Anaerobic
respiration
uses oxygen
without oxygen
cells that use it
occurs in most cells
occurs in bacteria,
yeasts, and in muscle
cells
production of
lactic acid
not
yes
amount of energy
released
high
low
definition
Aerobic
respiration
Anaerobic
respiration
lactic acid, energy,
products
carbon dioxide,
water, energy
reactants
glucose, oxygen
glucose
site of reactions
cytoplasm and
mitochondria
cytoplasm
ethyl alcohol, energy,
carbon dioxide
Write the word equation and the balanced chemical
symbol equation for aerobic respiration in living
organisms.
glucose + oxygen → carbon dioxide + water
C6H12O6 +
6O2 →
6CO2
+ 6H2O
Write the word equation for anaerobic respiration in
plants and in animals.
Plants:
glucose → ethanol + carbon dioxide
Animals:
glucose → lactic acid
Gas exchange
Understand the role of diffusion in gas exchange.
Flowering plants
Understand gas exchange (of carbon dioxide and
oxygen) in relation to respiration and photosynthesis.
Explain how the structure of the leaf is adapted for
gas exchange.
Stomata only lower epidermis.
Spongy mesophyll cells allow gases to diffuse to all the
cells.
The leaf has large internal surface area.
Leaves are thin, gases never have far to travel.
Describe the role of stomata in gas exchange.
Carbon dioxide and oxygen enter and leave the plant
through the stomata. The stomata open wider when the
leaf is exposed to light and tend to close again during
the dark. There is a greater demand for gas exchange
while the plant is photosynthesising as well as respiring.
Humans
Describe the structure of the thorax, including the
ribs,
intercostal
bronchi,
muscles,
bronchioles,
membranes.
diaphragm,
alveoli
and
trachea,
pleural
Understand the role of the intercostal (between ribs)
muscles and the diaphragm in ventilation.
Explain how alveoli are adapted for gas exchange by
diffusion between air in the lungs and blood in
capillaries.
Understand the biological consequences of smoking
in relation to the lungs and the circulatory system,
including coronary heart disease.
Tar can cause cancerous mutations in the lungs.
Smoke removes the cilia which keep the lungs clean.
Smoking also hardens the arteries, constricting the
blood flow and putting strain on the heart, resulting
in coronary heart disease.
http://www.drugabuse.gov/publications/researchreports/tobacco/what-are-medical-consequencestobacco-use
Describe experiments to investigate the effect of
exercise on breathing in humans.
Experiment
Variables
Procedure
Data collection
Data processing
Conclusion
Transport
Understand why simple, unicellular organisms can
rely on diffusion for movement of substances in and
out of the cell.
Understand the need for a transport system in
multicellular organisms.
Simple unicellular organisms can obtain all the nutrients
and gases they require by simple diffusion, and excrete
waste products in the same way. Their surface area,
over with exchange with the external environment can
occur, is large enough when compared to their total
volume.
In larger organisms the cell nuclei situated towards the
centre would not receive all the nutrients they needed
and excretion of waste products would be a problem
unless some form of transport system were used.
Flowering plants
Describe the role of xylem in transporting water and
mineral salts from the roots to other parts of the
plant.
Xylem vessels are long tubes made up of the hollow
remains of dead cells. They carry water and dissolved
minerals up from the roots, through the stem, to the
leaves. They also give support to the plant.
In roots the xylem and phloem vessels are usually
grouped together separately, but in the stem and leaves
they are found together as vascular bundles or veins.
Explain how water is absorbed by root hair cells.
Roots are covered in tiny root hair cells, which increase
the surface area for absorption. Water enters by osmosis
because the solution inside the cells is more
concentrated than the water in the soil.
Water continues to move between cells by osmosis until
it reaches the xylem vessels, which carry it up to the
leaves.
Understand that transpiration is the evaporation of
water from the surface of a plant.
In the leaves, water moves out of the xylem and enters
the leaf cells by osmosis. Water evaporates from the
surface of the cells inside the leaf and then diffuses out
through the open stomata. The evaporation of water
causes more water to rise up the xylem from the roots.
Water loss from the leaves is known as transpiration.
The flow of water through the plant from the roots to
the leaves is known as the transpiration steam.
Transpiration brings up water and minerals from the
soil. As water evaporates it cools the plant.
Explain how the rate of transpiration is affected by
changes in humidity, wind speed, temperature and
light intensity.
Transpiration occurs faster in conditions that encourage
evaporation, so when:
warm,
windy,
dry,
sunny.
Describe experiments to investigate the role of
environmental factors in determining the rate of
transpiration from a leafy shoot.
Potometer.
https://www.youtube.com/watch?v=oUr1P9RZnEU
Experiment
Variables
Procedure
Data collection
Data processing
Conclusion
Humans
Describe the composition of the blood: red blood
cells, white blood cells, platelets and plasma.
Understand the role of plasma in the transport of
carbon dioxide, digested food, urea, hormones and
heat energy.
Explain how adaptations of red blood cells, including
shape, structure and the presence of haemoglobin,
make them suitable for the transport of oxygen.
Adaptation of red blood
How it helps
cells
Large
surface
area
for
Biconcave disc shape
oxygen to enter and leave
No nucleus
More room to carry oxygen
Contains haemoglobin
It combines with oxygen
Adaptation of red blood
How it helps
cells
Can fit inside the smallest
Small
blood capillaries
Can squeeze into the smallest
Flexible
capillary
Large number
Can carry a lot of oxygen
Describe how the immune system responds to disease
using white blood cells, illustrated by phagocytes
ingesting pathogens and lymphocytes releasing
antibodies specific to the pathogen.
Describe the structure of the heart and how it
functions.
The heart contains several valves and four chambers,
two called atria and two called ventricles. The atria have
thin walls. They collect blood before it enters the
ventricles.
The ventricles have thick muscular walls that contract,
forcing the blood out. The valves allow the blood to
flow one way only, preventing it flowing back.
The heart is two pumps in one. The right side pumps
blood to the lungs to collect oxygen. The left side
pumps the oxygenated blood around the rest of the
body. The deoxygenated blood returns to the right side
of the heart before sent to the lungs again.
Explain how the heart rate changes during exercise
and under the influence of adrenaline.
Experiment
Variables
Procedure
Data collection
Data processing
Conclusion
During exercise adrenaline is released from the adrenal
glands. Adrenaline has two effects of the heart:
1. Makes it beat faster
2. Makes each beat harder
The combined effect is to massively increase the
volume of blood pumped by the heart per minute.
Describe the structure of arteries, veins and
capillaries and understand their roles.
Blood
vessel
Function
Adaptation
Explanation
High pressure to
Carry blood Thick
Arteries
away
heart
withstand
and
from muscular and maintain,
elastic wall
Elastic
reduces it
wall
Blood vessel
Function
Adaptation
Thinner wall
Explanation
Lower pressure,
no
need
to
withstand
Carry
blood
Veins
Large lumen
Less resistance
towards heart
to blood flow
Valves
Prevent
flow
back
Blood vessel
Function
Adaptation
Explanation
Thin, permeable
Substances can
wall
enter and leave
(one cell thick)
blood
Exchange
Capillaries
substances
Can
reach
inside
body
with cells
Small size
tissues and cells
Understand the general structure of the circulation
system to include the blood vessels to and from the
heart, the lungs, the liver and the kidneys.
Excretion
Understand the origin of carbon dioxide and oxygen
as waste products of metabolism and their loss from
stomata of a leaf (in flowering plants).
carbon dioxide: respiration
oxygen: photosynthesis
Leaf structure.
Understand that the lungs, kidneys and skin are
organs of excretion.
lungs: remove carbon dioxide from blood.
kidneys: remove urea from blood.
skin: removes water and salts by sweating.
Understand how the kidney carries out its roles of
excretion and osmoregulation.
Excretion: removal of toxic materials, the waste
products of metabolism and substances in excess of
requirements from organisms.
Carbohydrates and lipids only contain C, O, H but
proteins contain N as well. Amino acids are broken
down in the liver. They are turned into carbohydrates
and urea. The urea passes into the blood and travels to
the kidneys.
Osmoregulation: refers to the control of the levels of
water and mineral salts in the blood. It is a homeostatic
mechanism and it keeps the organism's fluids from
becoming too diluted or too concentrated.
Describe the role of ADH in regulating the water
content of the blood.
Osmoregulation
The hypothalamus detects changes in the amount of
water present in the blood. If there is too little water (the
blood is too concentrated) it tells the pituitary gland to
secrete ADH.
Osmoregulation
This hormone has an effect on the kidney; ADH makes
the kidney re-absorb water from the ultra-filtrate.
Higher levels of ADH make the kidney work harder to
reabsorb more water.
Osmoregulation
This results in the production of very small quantities of
very concentrated urine. The result of reabsorbing water
is to reduce the concentration of the blood.
Summary
Too little water in the blood, detected by the
hypothalamus.
More ADH produced by the pituitary gland.
Summary
More water reabsorbed by the kidneys, caused by ADH.
Blood becomes less concentrated (becomes more
diluted).
Summary
When the blood becomes too dilute, our pituitary glands
stop making ADH. The kidney stops reabsorbing water.
Summary
Large volumes of very dilute urine are formed. This is
just the opposite of what happens when your blood is
too concentrated.
Summary
Too much water in the blood, detected by the
hypothalamus.
Less
ADH
produced
by
the
pituitary
gland.
Less water reabsorbed by the kidneys, caused by ADH.
Summary
Blood becomes more concentrated.
Pituitary produces more ADH.
Blood returns to correct osmotic concentration.
When the concentration of the blood starts to rise, the
pituitary gland starts to make ADH again. Eventually
the concentration of the blood will return to normal.
Describe the structure of the urinary system,
including the kidneys, ureters, bladder and urethra.
Describe the structure of a nephron, to include
Bowman’s capsule and glomerulus, convoluted
tubules, loop of Henlé and collecting duct.
Describe ultrafiltration in the Bowman’s capsule and
the composition of the glomerular filtrate.
Your blood enters the glomerulus (a bunch of blood
capillaries linking to Bowman's capsule) under high
pressure. It is filtered through capillary wall of the
glomerulus.
The holes in the capillary allow the blood to pass
through while trapping (holding back) larger particles
(blood cells) as well as molecules like proteins.
What passes through the ultrafiltration system becomes
the filtrate. This includes: glucose, water, ions, some
amino acids, and urea.
Understand that selective reabsorption of glucose
occurs at the proximal convoluted tubule.
Understand that water is reabsorbed into the blood
from the collecting duct.
Understand that urine contains water, urea and
salts.
Coordination and response
Understand that organisms are able to respond to
changes in their environment.
Understand that homeostasis is the maintenance of a
constant internal environment and that body water
content and body temperature are both examples of
homeostasis.
Understand that a coordinated response requires a
stimulus, a receptor and an effector.
Stimulus: change in the environment that triggers a
response.
Receptor: a special cell adapted to detect stimuli.
Effector: A muscle, gland, or organ capable of
responding to a stimulus.
Coordination and response in flowering plants
Understand that plants respond to stimuli.
A 'tropism' is a growth in response to a stimulus. Auxin
is a plant hormone produced in the stem tips and roots,
which controls the direction of growth.
Describe the geotropic responses of roots and stems.
Describe positive phototropism of stems.
Response
Part of plant
Direction of
growth
Advantage
To get
Positive
Growth
maximum
towards light
light for
Stem tip
phototropism
photosynthesis
Negative
Growth away Less chance of
Root tip
phototropism
from light
drying out
Response
Part of plant
Direction of
growth
Advantage
More chance
Positive
Towards
Root tip
geotropism
of finding
gravity
moisture
Negative
Away from
More chance
gravity
of finding light
Stem tip
geotropism
Coordination and response in humans
Describe how responses can be controlled by nervous
or by hormonal communication and understand the
differences between the two systems.
Nervous system
Endocrine system
information passes as electrical information passes as chemical
impulses along neurons
messengers in the blood
effects are usually slow and longer
effects are rapid and short-lived
lasting
affects particular organs
affects the whole of the body
controls
growth,
development,
often involves reflexes
metabolism, and reproduction
Understand that the central nervous system consists
of the brain and spinal cord and is linked to sense
organs by nerves.
Understand that stimulation of receptors in the sense
organs sends electrical impulses along nerves into
and out of the central nervous system, resulting in
rapid responses.
Describe the structure and functioning of a simple
reflex arc illustrated by the withdrawal of a finger
from a hot object.
https://www.youtube.com/watch?v=Y5nj3ZfeYDQ
Describe the structure and function of the eye as a
receptor.
sclera (white protective covering of the eye),
cornea (front of the sclera, the curved surface is very
important in refracting the light towards the retina),
conjunctiva (thin transparent layer continuous with the
epithelium of the eyelids),
choroid (black layer which prevents internal reflection
of light and contains blood vessels to supply the retina),
aqueous humour (clear solution of salts),
pupil (variable opening in the iris to allow light to enter
the eye),
iris (coloured part of the eye, circular and radial
muscles which control the size of the pupil),
vitreous humour (clear gelatinous substance which fills
the eyeball),
retina (contains rods and cones and nerve cells for
vision),
lens (transparent, elastic bi-convex structure which
focuses the light onto the retina),
fovea (yellow spot contains cones only, spot of most
accurate vision),
optic nerve (carries impulses to the brain),
blind spot (point where optic nerve leaves the eye, not
light sensitive).
https://www.youtube.com/watch?v=XkLnpPi3JpU
http://www.bbc.co.uk/science/humanbody/body/factfiles
/sight/sight_animation.shtml
Understand the sources, roles and effects of the
following hormones: ADH, adrenaline, insulin,
testosterone, progesterone and oestrogen.
hormone
source
role
effects
controls how high concentration –
ADH
hypothalamus, much water small
pituitary gland is
in
blood
volume
the concentrated
vice versa
of
urine,
hormone
source
role
effects
fight or flight, increases blood sugar
adrenaline
adrenal
gland
prepares
the level, heart rate, blood
body for physical pressure,
activity
breathing
rate, sweat production
hormone
source
role
effects
liver cells take up
glucose and store in
insulin
controls blood
pancreas
the form of glycogen,
glucose level
decreases
glucose level
blood
hormone
source
role
controls
testosterone
testes
secondary
effects
it fuels a healthy
libido, builds muscle
sexual characteristics
in males
mass,
deep
voice,
body hair
controls
progesterone ovaries cycle,
pregnancy
menstrual
maintains
maintenance
endometrium
of
hormone
source
role
controls
oestrogen
ovaries
secondary
sexual characteristics
in females, controls
menstrual cycle
effects
stimulates ovulation,
maintenance
endometrium
of