The Nervous System

The Nervous Systems

Central Nervous System (CNS): Made up of the _________________ and ___________________, the CNS acts as the coordinating centre for mechanical and chemical actions

Peripheral Nervous System (PNS): Consists of the __________ that carry information between the organs of the body and the central nervous system. The PNS can be divided further: - ____________ – controls the skeletal muscle, bones, and skin (conscious) - ____________ – controls the internal organs of the body (not conscious)

Lets take a closer look at these sub-divisons of the nervous system….

Anatomy of the Nerve Cell The nervous system is made up of two different types of cells:

Glial Cells: These cells are _____________________________ of nerve impulses. Instead, they provide _________________ and metabolic activity to the nerve cells. These metabolic activities include: nutrition, maintaining homeostasis, and formation of myelin.

Neurons: These are the ______________________ of the nervous system by conducting _______________________. They are what allow us to control both voluntary and involuntary activities of the body.

There are 3 different types of neurons cells: Sensory Neurons, Interneurons, Motor Neurons

The Neuron Dendrite: The section of the neuron which

_____________________. They send the

signal into the cell body towards the axon.

Axon: __________ the signal away from

the cell body.

Myelin: A _____________________ the

axons allowing signals to travel faster

between neurons. (Protects neuron)

Schwann Cells – a special ____________

that forms the myelin

Nodes of Ranvier – The ______________

the sections of myelin

Sensory Neurons

Sensory Neurons are neurons that carry impulses from ________________ ________________ to the central nervous system (CNS) for processing by the brain

AKA – afferent neurons

Sensory Neurons are found in ___________ called ganglia (ganglion)

Sensory Neurons Some examples: In eyes – called ______________

which respond to light In nose – called ______________

which are sensitive to chemicals In skin – called ______________

which respond to temperature changes and others that respond to touch

Receptive Fields

Each sensory neuron has a _____________________ _________________ where that one neuron will receive stimuli from. These receptive fields have the ability to __________. Receptive fields are larger in our back and forearms, and much smaller in our lips, and finger pads.

Interneurons These neurons are predominantly found within the ____________________ ___________.

They come in many forms and process the incoming signals by the ___________ neurons then in response, signal the appropriate _________ neurons into action.

As the name suggests, they ________ neurons within the body.

Motor Neurons

Motor neurons receive information from ________________.

They will then___________________ to the effectors and cause a response in the target muscles, organs, or glands.

Impulses are carried FROM _______ TO ____________ via _______

AKA – efferent neurons

Neurons Travel in Bundles Neurons travel throughout our body in bundles referred to as ____________.

Neural Circuits When we feel pain, we don't stop to think about how much that pain hurts. For example if we touch a hot stove, we pull our hand away quickly without thinking about it. This is referred to as a _________________.

The reflex arc begins when a __________ picks up a __________. Sensory information is sent to the ___________, and ______________ relay this information directly to the __________neuron. The motor neuron activates the muscle, causing it to contract. This allows our bodies to react as quick as possible.

1) Touch receptor senses the tack (stiumulus) 2) Sensory information is relayed from sensory neuron (purple) to spinal

cord 3)  Interneurons (green) in spinal cord receive the sensory information and

relay it to a motor neuron (red) 4) Motor neuron activates the muscle cell (the effector), causing it to

contract