Download Divisions of the Nervous System

Divisions of the Nervous
System:
Central Nervous System
Objectives
• Identify and contrast the two divisions of the
nervous system
• Explain the functions of the brain and spinal
cord
• Explain the functions of the main parts of the
brain
Introduction
• The nervous system is divided into two parts:
• Central nervous system relays messages, processes
information, and analyzes information
• Peripheral nervous system receives information from the
environment and relays commands from the central nervous
system to organs and glands
Central Nervous System (CNS)
• Consists of the brain and spinal
cord
– Skull and vertebrae column
protect the brain and spinal cord
• Meninges are connective
tissues that wrap around the
brain and spinal cord
• Cerebrospinal fluid bathes the
brain and spinal cord and acts
as a shock absorber to protect
the CNS
– Also allows for the exchange of
nutrients and wastes between the
blood and nervous tissue
The Brain
• Impulses flow to and
originate from the brain
• Contains approx. 100
billion neurons
• Main parts include:
–
–
–
–
–
Cerebrum
Cerebellum
Brain stem
Thalamus
Hypothalamus
Cerebrum
• Largest region of the brain
• Responsible for the voluntary
activities of the body
• Site of intelligence, learning, and
judgment
• Divided into right and left
hemispheres
– Each controls the opposite side of the
body
– Right side may be associated with
creativity and artistic ability
– Left side may be associated with
analytical and mathematical ability
• Folds and grooves increase surface
area
Cerebrum
• Consists of two layers:
• Outer layer is the cerebral cortex
– Consists of gray matter (densely
packed nerve cell bodies)
– Processes info from the sense
organs and controls body
movements
• Inner layer consists of white
matter
– Bundles of axons and myelin
sheaths
– Connects the cerebral cortex and
the brain stem
Cerebellum
• Second largest region of
the brain
• Located at the back of
the skull
• Coordinates and
balances the actions of
the muscles so the body
can move gracefully
Brain Stem
• Connects the brain and spinal
cord
• Located below the
cerebellum
• Regulates flow of info
between brain and the rest
of the body
• Contains two regions
– Pons – relay center between
the cerebrum and cerebellum
– Medulla oblongata – relay
center and controls many
homeostasis activities, such as
heart rate and respiration
Thalamus & Hypothalamus
• Found between the brain stem
and the cerebrum
• Thalamus receives messages
from all sensory receptors and
relays info to the proper
region of the cerebrum for
processing
• Hypothalamus is the control
center for recognition and
analysis of hunger, thirst,
fatigue, anger, and body temp.
– also controls the coordination of
the nervous and endocrine
systems
The Spinal Cord
• The main communications
link between the brain and
the rest of the body
• Certain kinds of information,
such as reflexes, are
processed directly in the
spinal cord
• A reflex is a quick, automatic
response to a stimulus
– Allows the body to respond to
danger immediately
– Examples: blinking and
squeezing
Notes Review
• Identify and contrast the two divisions of the
nervous system
– Central nervous system relays messages,
processes information, and analyzes information
– Peripheral nervous system receives information
from the environment and relays commands from
the central nervous system to organs and glands
Notes Review
• Explain the functions of the brain and spinal
cord
– The brain is the site where all nerve impulses flow
to and originate from.
– The spinal cord is the main communications link
between the brain and the rest of the body.
Notes Review
• Explain the functions of the main parts of the brain
– Cerebrum is responsible for the voluntary activities of the
body and is the site of intelligence, learning, and judgment
– Cerebellum coordinates and balances the actions of the
muscles so the body can move gracefully
– Brain stem regulates the flow of information between the
brain and the rest of the body
– Thalamus receives messages from all sensory receptors
and relays info to the proper region of the cerebrum for
processing
– Hypothalamus is the control center for recognition and
analysis of hunger, thirst, fatigue, anger, and body temp.