Transcript The Nervous System

The Nervous System
Structures and Control
Central Nervous System
Already know it consists of the brain and
spinal cord
 Both are bathed in the cerebrospinal fluid

◦ Both protects and nourishes

This is encased in the meninges – three
layers of connective tissue
Parts of the Human Brain
Cerebrum
Thalamus
Pineal gland
Hypothalamus
Pituitary gland
Cerebellum
Pons
Brain stem
Medulla
oblongata
Spinal cord
Cerebrum
• Largest section, made of many folded
regions called fissures (why?)
• Longitudinal central fissure runs through
the middle, dividing the brain into
hemispheres
• Right and left connected by corpus
callosum
• Controls voluntary actions
• Further divided into four lobes

Each lobe has specific controls
Outer portion is the cerebral cortex,
made of grey matter
 Inner portion is made of white matter
 Consists of glial cells and myelinated
axons
 Glial cells outnumber neurons and
perform custodial roles

◦ Form myelin
◦ Provide nutirents
◦ Regulate extracellular material
Cerebellum
• Aka the “little brain”
• Responsible for coordination of motor
functions
• Also involved in language (although
poorly understood)
Brain Stem
• Two parts: pons and medulla oblongata
• Mediates flow between body and brain
Medulla
Thalamus
• Receives and relays information from
spine to appropriate area of cerebrum
Hypothalamus
• Connection between endocrine system
and nervous system
Spinal Cord
• Main highway system to central hub that
is the brain
Peripheral Nervous System
Divided into two parts: somatic and
autonomic
 Somatic said to be under voluntary
control

◦ Though it involves sensory neurons and
motor neurons connected to skeletal muscle
Autonomic can be thought of as
“automatic”
 Actions that are involuntary

Further divided into two sections:
sympathetic and parasympathetic
 Perform opposite roles in body

Sym vs para