the nervous system!

Nervous system

Made of the structures that control the actions and reactions of the body in response to stimuli from the environment

CNS stands for:

central nervous system

PNS stands for:

Peripheral nervous system

what does the cns consist of?

the brain and the spinal cord

what does the pns consist of?

sensory and motor neurons

Brain

The body’s central command organ that constantly receives impulses from all over the body

Spinal cord

A structure that allows the brain to communicate with the rest of the body

Function of the PNS

Connects the CNS to the rest of the body

Parts of the PNS

Sensory and motor

Involuntary actions

Processes that the brain controls that happen automatically (e.g. heart beating)

Voluntary actions

Processes that you can control yourself (e.g. moving arms and legs)

Main areas of the brain

Cerebrum, cerebellum, brain stem

Cerebrum

Largest part of the brain where you think and problem-solve, and where memories are stored. Controls voluntary movements and senses

Cerebellum

Second largest part of the brain that processes information from your body, and allows the brain to keep track of your body’s position and coordinate movements

Brain stem

Connects the brain to your spinal cord. the medulla controls involuntary processes, such as blood pressure, body temperature, heart rate, and breathing.

The spinal cord

Made of a bundle of nerves surrounded by protective bones called vertebrae

Nerves

A collection of nerve cell extensions bundled together with blood vessels and connective tissue, they’re also everywhere in the body

What does the spinal cord do?

special cells carry sensory information to the spinal cord, which carries these impulses to the brain. the brain interprets these impulses as a sensation and sends information back to the spinal cord.

A: Brain stem, B: Cerebrum, C: Cerebellum

What are the parts of a neuron?

A large region called the cell body, a long extension called the axon, short branches called dendrites, and an axon terminal.

Dendrite

A short, branched extension of the cell body. A neuron has one, two, or multiple.

Axon

Extensions of the neuron which carry away impulses from the cell body. A neuron only has one, and they can be short or long.

Axon terminal

Where a signal is changed from an electrical signal to a chemical signal

Neurotransmitter

Chemical signal that is released into the gap between the neuron and other cells

A: Dendrite, B: cell body, C: axon, D: axon terminal

Neuron

A cell that moves messages in the form of fast-moving electrical energy

Impulses

Electrical messages moved by neurons

Glial cells

Cells that protect and support neurons

Function of sensory neurons

Gather information from in or around your body, and move the information to the brain.

Function of motor neurons

Move impulses from the brain and spinal cord to other parts of the body

Sensory organs

Eyes, mouth, ears, skin, and nose.

Cornea

A clear membrane that covers the front of the eye

Pupil

An opening in the eye where light in an object passes

Lens

An oval-shaped piece of clear, curved material in the eye

Retina

A layer of light-sensitive photoreceptor cells that change light into electrical impulses

Eardrum

A thin membrane separating the outer ear from the middle ear

Cochlea

A fluid-filled organ of the outer where vibrations make waves in the fluid.

The five basic tastes

sweet, sour, salty, bitter, and savory..

Olfactory cells

Sensory receptors in the nose that react to chemicals in the air