Neuron Structure

Previous Lesson’s

Somatic Nervous System
The main function of the somatic nervous system is to transfer __
__ __ __ __ __ __ __ from CNS to skeletal muscles. It controls
voluntary movements. It consists of:
•Cranial Nerves (__ __ pairs)
•Spinal Nerves (__ __ pairs)
There are 12 pairs of cranial nerves that come from the __ __
__ __ __. Examples of cranial nerves are optic, auditory &
olfactory, etc.
Spinal nerves come from the __ __ __ __ __ __
__ __ __ __. There are 31 pairs of spinal nerves.

Autonomic Nervous System

The autonomic nervous system relays
__ __ __ __ __ __ __ __ from the Central Nervous System to the involuntary
organs and smooth muscles of the __ __ __ __. It regulates involuntary and
unconscious actions, such as internal-organ function, breathing, digestion, and
heartbeat.
It is divided into two parts that work opposite to each
other:
•Sympathetic Nervous System
•Parasympathetic Nervous System
The sympathetic nervous system has nerves from the spinal cord between
the neck and waist region. It prepares the body for violent actions and is
generally stimulated by adrenaline. It is responsible for the body’s “fight or
flight” response to danger.
The parasympathetic nervous system is mainly involved in re-establishment
of normal conditions when violent action is over. This calms the body after
action.
PNS includes two types of nerve fibers:
Afferent nerve fibers – responsible for transmitting messages from tissues
and organs to the CNS.
Efferent nerve-fibers– responsible for conveying messages from CNS to the
organ that responds.

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STUDENT OBJECTIVES: After watching an multimedia PowerPoint, with an accuracy of 71%, you

should be able to:

1. Define: cavity, organ, diaphragm, thorax, thoracic, abdomen,

abdominal, cranial, appendages,

2. Identify & name 20 body organs:

3. Locate each organ named in a model and a diagram of the

human body

4. Name specific organs contained in the 3 main body cavities, (i)

cranial, (ii) thoracic, (iii) abdominal.

OK

Write this
down

STUDENT OBJECTIVES: After watching an multimedia PowerPoint, with an accuracy of 71%, you should be able

to:

1. Define: cavity, organ, diaphragm, thorax, thoracic,

abdomen, abdominal, cranial, appendages,

2.Identify & name 20 body organs:

3.Locate each organ named in a model and a diagram of the

human body

4.Name specific organs contained in the 3 main body cavities,

(i) cranial, (ii) thoracic, (iii) abdominal.

K

W

L

What do I
KNOW?

What do I

WANT to know?

What have I

LEARNED?

List 3 things that
YOU know about
Forms of Energy.

1
2
3

Write 1 question
that you want to
LEARN about
Transfer of Energy.

*Questions begin with a capital letter &
end with a question mark.

List 3 things that
YOU learned
(NEVER knew before)
about Transfer of
Energy.

K

W

L

What do I
KNOW?

What do I

WANT to know?

What have I

LEARNED?

List 3 things that
YOU know about
Energy Transfer.

1
2
3

Write 1 question
that you want to
LEARN about

Forms of

Energy.

*Questions begin with a capital letter &
end with a question mark.

List 3 things that
YOU learned
(NEVER knew before)
about Transfer of
Energy.

K

W

L

What do I
KNOW?

What do I

WANT to know?

What have I

LEARNED?

List 3 things that
YOU know about
Energy Transfer.

1
2
3

Write 1 question
that you want to
LEARN about
Transfer of Energy.

*Questions begin with a capital letter &
end with a question mark.

List 3 things that
YOU learned
(NEVER knew before)
about Transfer of
Energy.

MARCH is

SCIENCE month

Psalms 18:2
The Lord is my protector; he is my strong
fortress. My God is my protection, and with
him I am safe. He protects me like a shield; he
defends me and keeps me safe.

OK

ervous
System

The second control system;
controls fast actions

Neuron Structure
A Neuron (nerve cell) is a structured single cell. Neurons are unique because
they can be very long. Neurons are irregular in shape & long; and able to
conduct electrical signals.
1.

Cell body – cytoplasm, nucleus & organelles

2.

Cytoplasm - grainy

3.

Nucleus - Large, centrally located, controls the neuron

4.

Dendrite (tiny nerve fibres) – carry impulses toward the cell body. It is the
shortest fibre.

5.

Axon – (long nerve fibre) - a single long fiber that carries impulses away
from the cell body. The longest fiber on the cell body. The axon branches at
the tip. It has a myelin sheath around it.

6.

Myelin Sheath – a fatty protective sheath over the axon. It insulates the
axon. The myelin sheath transmits the impulse faster. It is formed by
individual Schwann cells.

7.

Schwann cells – cells that form the myelin sheath

8.

Node of Ranvier – gaps in the myelin sheath

9.

Synapse – gap (space) between a pair of neurons. Nerve impulses pass
over the synapse when moving from one neuron to another

.

Lesson Review:

1. What is a energy? {1}
2. How do you know that work has been done? {1}
3. What is the definition of ‘kinetic energy’? {1}
4. What factors can affect the amount of kinetic energy of an object? {3}
5. If object A is 10 meters high & object B is 30 meters high. Which

object will have more kinetic energy? {1}

Total - 7

YOU are
the future
& the future

Is

_______________

DO NOT THROW AWAY YOUR NOTE BOOKS FROM

GRADE 7

GRADE 8

GRADE 9

YOU NEED
THEM TO

STUDY

SUCCESSFULLY

TO PASS
THE B.J.C.

SCIENCE

EXCITING