Faiza Tufail
P2 Unit 5
P2 – The main tissue types of the body and the role these play in two named
organs of the body.
There are four main types of tissues in the body.
The four main types of tissues are; connective
tissue, epithelial tissue, muscle tissue and
nervous tissue.
Connective Tissue
Connective tissues are a form of fibrosis tissue.
They provide support and hold structures like
bones, cartilages, blood etc. There are three
types of fibrosis tissue;
• Collagenous Fibres – is a group of protein
that occurs naturally. This fibrosis tissue is
made of collagen and consists of bundles of
fibrosis that are coils of collagen molecules.
• Elastic Fibres – this fibrosis tissue is made up of elastic so it is stretchable.
• Reticular Fibres – are very delicate and form fine networks instead of thick
bundles. This fibrosis tissue joins connective tissues to other tissues.
The following; blood, cartilage, bone, areolar and adipose are all forms of connective
tissues.
Epithelial Tissue
Epithelial tissue covers the whole surface of the body. It is made up of cells that are
joined very closely and arranged in one or more layers. This tissue is specialised to
form the covering or lining of all internal and external body surfaces. Epithelial
tissues can be divided into two groups depending on the number of layers of which it
composes. The role of an epithelial tissue is to cover the surface of the body. There
are five types of simple epithelial tissue;
Squamous Epithelium – the appearance of this tissue is thin, flat plates.
Squamous epithelium could be found in the mouth, blood vessels, heart, lungs skin
etc.
Simple Cuboidal Epithelium – the appearance of this tissue is roughly square
or cuboidal in shape. This tissue is found in the lining of the kidney tubules as
well as in the ducts of glands.
Simple Columnar Epithelium –the appearance of this tissue is column shaped.
It forms the lining of the stomach and intestines. Some columnar cells are
specialised for sensory reception such as the nose, ears, taste buds, tongue.
Ciliated Columnar Epithelium – the appearance of this tissue are fine hair-like
outgrowths, cilia on a free surface. Ciliated columnar epithelium is found
in air passages like the nose. It could also be found in the uterus and
fallopian tubes in females.
Stratified Epithelium – the appearance of this tissue is flat and scaly from the top,
it may or may not be keratinised. This tissue is found on the skin surface.
Faiza Tufail
P2 Unit 5
Muscle Tissue
Muscle tissue is responsible for the movements of the body and the various parts of
the body.
Smooth Muscle Tissue – this muscle tissue is found in various parts of the body such
as the arteries, bladder, digestive tract, blood vessels, gut, internal tubes etc. The role
of a smooth muscle tissue is to contract organs such as blood vessels, bladder and
uterus.
Skeletal Muscle Tissue – this muscle tissue is attached to bones by tendons and is
associated with the body voluntary movements. This muscle is a striated muscle.
Cardiac Muscle Tissue – this muscle tissue is found in the heart. Calls are joined to
one another by intercalated discs which allow the synchronization of the heart beat.
Cardiac muscle is branched and a striated muscle.
Nervous Tissue
Nervous tissues are cells that can convert stimuli (a change in the internal and
external environment) to epithelial impulses and conduct those impulses for example;
Temperature - a person may pull away from an object with a high temperature. This
is known as the reflex arm.
Light – An individual’s eye may become bigger in the dark as it is trying to find light
to see better and a little clearer. The pupil will become bigger in the dark and smaller
in the light.
There are two types of nervous tissues;
Neurons -Billions of neurons vary in size, in which human bodies consist of. Neurons
could be broken down into the cell body, which contains each neuron’s nucleus,
mitochondria, and nerve processes. Neurons, nerve cells are very sensitive to various
types of stimuli such as heat/cold, light/dark pressure.
Neuroglia -The Neuroglia also known as ‘glia’, maintains homeostasis, from myelin,
and provides support and protection for the brains neurons. Some ‘glia’ cells maintain
homeostasis, form myelin, and provide support and protection for the brain's neurons.
Faiza Tufail
P2 Unit 5
Muscle Tissue - Heart
The heart is a large pump, which pumps blood around the body. The muscle tissue
around the human heart, like all tissues in the body relies on blood supply to deliver
oxygen and nutrients and to remove waste products such as CO2.
The left side of the
heart has to pump
blood around the
whole body
therefore, it has
thicker muscle
tissue, as the blood
has to travel a
longer distance.
The right side of the
heart has thinner
muscle tissue,
because it only has
to pump
deoxygenated blood
to the lungs, which
is close to the heart,
therefore the heart
does not have to
pump as much as
the left side.
Nervous Tissue – Brain
A brain is a Nervous Tissue as it controls and regulates body
functioning. This is because messages are sent to and from the
brain. When a message comes into the brain from any part of the
body, the brain tells the body how to react for example, if a
person accidentally touch the hot iron, the nerves in their skin
will shoot a message of pain to their brain. The brain monitors
and regulates the body's actions and reactions. It continuously
receives sensory information, and rapidly analyzes this data and
then responds accordingly by controlling bodily actions and
functions. The brainstem controls breathing, heart rate, and
other autonomic processes that are independent of conscious
brain functions.