Nervous System

Objectives:1.Identify structures of the nervous

system.2.Explain differences in the function of the peripheral nervous system and the

central nervous system.

D. Nervous Tissue• Nervous tissue is

– found in the brain, spinal cord, and nerves. – made up of:

1. Neurons: nerve cells (bundles of axons)2. Neuroglial cells: helper cells

– “glia” = glue– Support and bind components of nervous tissue to

each other and to blood vessels– Function similarly to connective tissue in other

organ systems

Parts of a Neuron• Sketch neuron and label parts.

Nervous System• Organs of this system are divided into 2

groups:1. Central Nervous System (CNS)

• Brain• Spinal cord

2. Peripheral Nervous System (PNS)• Composed of the nerves (peripheral nerves)

that connect the CNS to other body parts• Functions of the nervous system:

1. Sensory2. Integrative3. Motor

1. Sensory Function• Sensory receptors at the ends of

peripheral neurons:– Gather info by detecting changes inside and

outside the body.• Inside: temperature and oxygen concentration• Outside: light and sound intensities

– Convert info into nerve impulses (electrochemical changes) which are transmitted along peripheral nerves to the CNS

2. Integrative Function• Nerve impulses are integrated (brought

together) in the CNS.• Allows us to make conscious or

subconscious decisions.

3. Motor Function• Peripheral nerves carry impulses from

the CNS to effectors (responsive structures).

• Effectors are NOT part of the nervous system, but include muscles and glands.

Motor Function• Motor functions can be divided into 2

groups:– Somatic nervous system

• Consciously controlled (voluntary)• Controls skeletal muscle

– Autonomic nervous system:• Involuntary• Includes heart, smooth muscle, and various

glands

Nervous System Function Recap

1. Detects changes inside and outside the body,

2. Makes decisions based on the information received, and

3. Stimulates muscles or glands to respond.

• What is the purpose of this process?????

Neuroglial Cells• Functions:

– Fill spaces– Provide structural frameworks– Produce myelin– Carry on phagocytosis

• Vary from CNS to PNS• Table: Type of Cell, Location, Function,

Other specific info