The human nervous system is composed of nerves, the brain, spinal cord, and meninges. It works with the endocrine system to regulate human behavior and life processes. The nervous system mediates quick actions through neural synapses using neurotransmitters, while the endocrine system is responsible for longer-term reactions. Key areas of the brain that influence human senses are the thalamus and hypothalamus.

1. Human Nervous System Overview
 Human Behavior
The endocrine system and the nervous
system are the two primary contributors to
human behavior.
The nervous system is the primary
mediator of human behavior.

2. Human Nervous System Overview
 Human Behavior
Grossly stated, the internal activities such
as life processes are regulated by the
endocrine system while the observable
behavior is mediated by the nervous
system i.e. the nervous system is
responsible for quick actions—the
endocrine system is responsible for
reactions over time.

3. Human Nervous System Overview
 Nervous System Organization
There are four main components of
nervous system performance. They are:
1. Nerves
2. The Synapse
3. The Brain
4. The Spinal Cord

4. Human Nervous System Overview
 Nerves
There are three basic types of nerves.
They are:
1. Sensory nerves (exclusively afferent)
2. Motor nerves (exclusively efferent)
3. Mixed nerves (both efferent & afferent)

5. Human Nervous System Overview
 The Synapse
Neural synapse travels in one direction
and is influenced by neurotransmitters.
About thirty have been identified.
With their identification, new drugs have
been created to either inhibit or facilitate
neural transmission.

6. Human Nervous System Overview
 The Brain
It is a highly specialized part of the
nervous system. In a sense, it is an
enlargement of the spinal cord.
We will focus much of our attention to the
thalamus and hypothalamus area of the
brain.
(integration of the human senses)

7. Human Nervous System Overview
 The Spinal Cord
It extends from the end of the
medulla oblongata (first cervical
vertebra) to the lower border of the
first lumbar vertebra.
It is surrounded by the protective
connective tissue—the meninges.

8. Human Nervous System Overview
 The Meninges
It is composed of three layers.
They are:
1. The Dura mater (outermost)
2. The Arachnoid mater (middle)
3. The Pia mater (innermost)
The cerebrospinal fluid is found between the
arachnoid and pia layers.

9. Human Nervous System Overview
 Cerebrospinal Fluid
It is produced by the choroid plexuses and
is replaced within the system every six
hours.
An acute infection can interfere with either
drainage or absorption and create
headaches, slowed pulse, and respiratory
rate.

10. Human Nervous System Overview
 Cerebrospinal Fluid
A fistula (spinal fluid leak) within the
inner ear will create a pressure
difference resulting in a patient
complaint of dizziness and headache.