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Organising the organism…read more

Slide 2

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Forming a lining ­ epithelial tissues
in animals
Animal tissues are grouped into 4 main categories: epithelial tissue ­ layers and
linings, connective tissues ­ hold structures together and provide support (examples
include cartilage, bone and blood), Muscle tissue ­ cells specialised to contract and
move parts of the body. Nervous tissue ­ cells that can convert stimuli to electrical
impulses and conduct those impulses.
Squamous epithelial tissue are made up of cells that are flattened, so they are very
thin, together they form a thin, smooth, flat surface.
This makes them ideal for lining the insides of tubes such as blood vessels, where
fluids can pass easily over them.
Squamous epithelial tissue also form thin walls, such as the walls of the alveoli in the
It provides a short diffusion pathway for the exchange of oxygen and carbon dioxide.
The Squamous cells are held in place by the basement membrane. This is secreted
by epithelial cells. It is made of collagen and glycoprotein's. Basement membrane
attaches epithelial cells to connective tissue.
Ciliated epithelial tissue is made up of column shaped cells. They are usually found
in the inner tubes of the trachea, bronchi and bronchioles and in the uterus and
oviducts. Ciliated cells have cilia that cover a large surface area some of them
produce mucus, the cilia synchronise and move the mucus.…read more

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Slide 4

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Harvesting light ­ cooperation in
Leaves are the major organs of photosynthesis in a plant. Their cells, tissues and
overall shape are arranged to help maximise the rate of photosynthesis.
Requirement for photosynthesis: light, water, carbon dioxide, presence of chlorophyll.
The waste product, oxygen is excreted.
The leaf is adapted in a number of ways:
1) Transparent upper layer, the upper epidermis lets light through.
2) Layer of cylindrical palisade cells underneath the epidermis. They are packed with
chloroplasts containing chlorophyll.
3) Loosely packed spongy mesophyll layer has many air spaces to allow circulation of
4) Lower epidermis layer has pores called stomata, this allows gases to be
exchanged between the leaf and the outside air. The stomata has guard cells are
not turgid, stomata closes and vice versa.
5) Leaf vein system containing xylem and phloem tissues supports the leaf as well as
carrying the transport tissues, which transport water in the leaf.…read more

Slide 5

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Opening and closing stomata ­ role
of guard cells
Guard cells are specialised
cells that appear in pairs on the
lower epidermis. They contain
chloroplasts, and their cell walls
contain spiral thickenings of
Water moves into these cells
they become turgid, because of
the spirals in the walls of the
inner edges, only the outer
walls stretch. The two guard
cells bulge at both ends so a
pore opens between them. This
pore is known as a stoma.…read more

Slide 6

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Locomotion ­ systems cooperation's
The muscular and skeletal systems work
together in order for movement to take place.
But this can happen only is the nervous
system instructs the muscles to coordinate
their actions.
As muscles and nerves work, they use energy.
They need a supply of nutrients and oxygen
from the circulatory system, which in turn
receives these chemicals form the digestive
and ventilation systems.…read more


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