Nervous System (Anatomy)

Central Nervous System (CNS)

Consists of the brain and spinal cord

Peripheral Nervous System (PNS)

Everything else

• cranial and spinal nerves (motor and sensory)

• Networks of nerves (plexuses) innervate muscles

Connects the CNS to the rest of the body

Autonomic Nervous System (ANS)

Controls glands and smooth and cardiac muscle

• involuntary controls with

  • Parasympathetic

  • Sympathetic

Parasympathetic

rest and digest (ANS)

• think paralyzed (you cant do anything)

Sympathetic

fight or flight (ANS)

• Sympathy - when you have sympathy for someone you take action and want to fight for them

Neurons

• consists of a cell body with projections

• dendrites

• axon

• myelin sheath

Dendrites

recieve incoming information and transmit impulses to the cell body

Axon

conducts impulses away from the cell body to another cell (soma)

• decides if it has enough power to go through (stockgate)

Myelin Sheath

insulates the axon and increases the speed of impulses transmitted

• ex. flat iron when a cord breaks, it dosnt’t get as hot

Sensory (Afferent) Neurons

When the nerve arrives at the brain

• transmit impulses from sensory receptors toward the central nervous system

When we get stronger we gain more muscle strength, same for growing more sensory neurons to do everyday activities

Interneurons (Association) Neurons

Connected, takes the sense, gives reaction, and give it to the exit

• shuttle signals through CNS pathways

• most are confined to the CNS

Motor (Efferent) Neurons

Creates a signal that says what the body needs to do

• carry impulses from the CNS to effectors (muscles and glands)

  • spine to muscles

Neurons

Cerebrum

largest part of the brain, located at the top and front of the brain

• thinking, feelings, senses, movement

Cerebellum

under cerebrum which is a motor function (makes everything look practiced)

• Think: Sarah (cere) is the bell of the ball

• MUSCLE MEMORY

Brain Stem

Controls survival basics, reflexes, and manages sleep

Motor Areas

(Cerebral Cortex)

• control voluntary movement

• contains majority of motor neurons

Sensory Areas

(Cerebral Cortex)

• conscious awareness of sensation

Association Area

(cerebral Cortex)

• executive function

• integrate diverse information

Nerves

Cable-like organs in the PNS

• Numerous axons wrapped in connective tissue

• Present in the CNS and PNS

  • 12 pairs of cranial nerves

  • 31 pairs of spinal nerves

Vagus Nerve

longest nerve in the body that connects your brain to your heart, lungs, and digestive system to control things like heart rate and digestion

Oculomotor Nerve

3rd pair of cranial nerves that control most eye related things

Optic Nerve

2nd cranial nerve that transmits visual information from the retina to the brain

Olfactory Nerve

first cranial nerve responsible for your smell

Heart Nerves

Cardiac branches of vagus nerve fibers arising from trunks of the Sympathetic Nervous System

• control your heart rate, pumping strength, and overall heart function

Respiratory Nerves

Respiratory Center

• Group of cell bodies located on each side of the medulla

• The network of central brainstem centers and peripheral nerves that controls the muscles of breathing and relay sensory feedback from the lungs

Cerebral Cortex

Motor areas, sensory areas, association area, integration, and executive function