Function/Organization/Parts of Neurons

What is the function of the nervous system (2) ?i i

1. To maintain homeostasis

2. Act as a communication system

What is integration ?i i

Integration is recieving input from the environment, coordinates input, then acts upon it .i i

What parts of the body make up the Central Nervous System (CNS) (2) ?i i

The brain and spinal cord .i i

What makes up the Peripheral Nervous System (PNS) (2) ?i i

1. All the nerves leading to and from the brain (cranial nerves)

2. Nerves of the spinal cord (spinal nerves)

What are the two subdivisions of the peripheral nervous system ?i i

1. Somatic nervous system

2. Autonomic nervous system

Describe the somatic nervous system (4) (control and travels where) .i i

1. Under voluntary control

2. Travels to the skeletal muscles, skin, and sensory organs

Describe the autonomic nervous system (1) .i i

1. Control the involuntary actions in our body

What are neurons ?i i

Neurons are the main structural and functional cells of the nervous system .i i

What do neurons do ?i i

Neurons carry messages in the nervous system .i i

What are the 3 types of neurons ?i i

1. Motor neurons

2. Sensory neurons

3. Interneurons

What do motor neurons do ?i i

Carry motor information from the CNS to the effectors .i i

What are effectors ?i i

Effectors are muscles, glands, and other organs that perform some type of action .i i

What do sensory neurons do ?i i

Carry sensory information to the CNS from the sensory receptors .i i

Where are interneurons found and what do they do ?i i

1. Found in the CNS

2. Connect the motor and sensory neurons

What are glial cells (3) ?i i

Glial cells are cells that support the neurons by providing insulation, support, and to nourish .i i

How many more glial cells are there in the brain than neurons ?i i

10x more glial cells than neurons in the brain .i i

What are nerves (2) ?i i

Nerves are composed of a collection of hundreds of neurons. Held together by a covering of connective tissue .i i

Name the 5 structures of a myelinated neuron .i i

1. Dendrite

2. Cell Body

3. Axon

4. Nodes of Ranvier

5. Terminal Branches

What are dendrites (3) ?i i

Dendrites are branch like extensions, recieve impulses (messages), and send them to the cell body .i i

What does the cell body contain and what does it do (3) ?i i

The cell body contains the nucleus and other organelles, and sends the impulse to the axon .i i

What does the axon do ?i i

Axons carry the impulse .i i

What does it mean if an axon is myelinated ?i i

A myelinated axon means it is wrapped with a type of glial cell called a Schwann Cell. Schwann cells form myelin which insulates the axon and appears white in colour .i i

What are Nodes of Ranvier ?i i

Nodes of Ranvier are gaps between Schwann Cells where the axon is bare .i i

What are terminal branches and what special structure do they have ?i i

Terminal branches are extensions at the end of the axon that have special structures called synaptic knobs .i i

Why are synaptic knobs important ?i i

Synaptic knobs are important when the impulse leaves the axon to travel to another neuron .i i