Transcript The Nervous System

The Nervous System
Coordinates all the body’s activity
The Nervous System
• 1. Two main divisions
• a. Central Nervous System (CNS) – consists
of brain and spinal cord
• b. Peripheral Nervous System (PNS) –
includes nerves extending from brain and
spinal cord
• c. The CNS receives messages from the PNS,
interprets them, and then sends out a
response.
Neurons
• 2. Neurons - nerve cells that transmit
messages to and from the spinal cord and
brain
• a. Sensory Neurons – carry messages FROM
body TO CNS
• ex. Playing games in computer lab. When
light switches to green, a sensory neuron
transmits a message from your eye to your
brain
Neurons
• b. Motor Neurons – carry message TO
body FROM CNS
• ex. Your brain sends a signal through a
motor neuron to tell your finger to
click the mouse.
• c. Interneurons – connect neurons
3. Structure and Functions of
Neurons
• 1. Dendrites – receive information and
transmit impulses toward cell body
• 2. Cell Body – large area which contains
cell nucleus or power plant
• 3. Nucleus – command center of the
neuron
• 4. Axon – transmit impulses away
from cell body and toward axon
terminal
• 5. Axon Terminals – branched
structures at the ends of neurons.
• 6. Myelin Sheath – insulating coat
which covers the axon. This helps
messages relay faster.
Neuron
Motor Unit
The Central Nervous System
• 1. The brain
• a. Helps you think, remember,
reason, feel emotion, and
coordinate muscle movement
• b. Divided into three main parts:
cerebrum, cerebellum, brain stem
The Brain
The Central Nervous System
• 2. The Cerebrum
• a. largest, most complex part of brain
• b. right and left sides communicate with
each other to coordinate movement.
Right controls left side and vice versa.
• c. left hemisphere is for language,
reasoning, and critical, concrete thinking
• d. right hemisphere is for abstract
thinking
The Central Nervous System
• 3. Four lobes (parts) of the cerebrum
• a. Frontal Lobe –use of language
• b. Parietal Lobe – sensory information,
including feelings of heat, cold, pain,
touch
• c. Occipital Lobe – Controls sense of
sight
• d. Temporal – sense of hearing and smell
Lobes of the Brain
The Central Nervous System
• 4. The Cerebellum
• a. second largest part of brain
• b. maintains body’s posture and
balance
• c. coordinates complex muscle
movements like serving a
volleyball or playing violin
The Central Nervous System
• 5. The Brain Stem
• a. 3 inch long stalk of nerve cells that
connect the spinal cord to the rest of
the brain
The Central Nervous System
• b. five parts
• 1. Medulla Oblongata – regulates heartbeat, breathing
rate
• 2. Pons – controls muscles of eye and face.
• 3. Midbrain – controls pupil size
• 4. Thalamus – relays incoming information from the
eyes, ears, and pressure receptors in skin
• 5. Hypothalamus – regulates body temp, appetite,
sleep
Brain Stem
The Peripheral System
• 1. Broken into two parts
• a. Autonomic Nervous System – controls
involuntary functions such as digestion and heart
rate
• - you cannot control this; it is automatic!
(autonomic)
b. Somatic Nervous System – voluntary
responses that are under your control
- feeling and itch on your skin and scratching it
The Peripheral System
• 2. Autonomic Nervous System
• a. Broken down into two smaller networks
• b. Sympathetic nervous system – kicks in when
you are startled. Messages are sent that
increase your heart rate. Also, blood vessels
dilate to allow for greater blood flow.
• - “Fight or flight response”
• - Example… you are riding in a car and a deer
jumps
out in front of you. Think about how you feel.
Your body prepares you to make a sudden
reaction.
The Peripheral System
• c. Parasympathetic nervous system –
opposite of sympathetic nervous
system
• - slows heartbeat, relaxes blood
vessels, lowers blood pressure
Problems of the Nervous
System
• 1. Headaches – caused by muscle
tension, eyestrain, sinus infection,
dehydration, or food allergies
• 2. Head injuries
• a. concussion – a temporary loss of
consciousness
http://www.youtube.com/watch?v=Tyv
4du7BTOc
Problems of the Nervous
System
• 3. Spinal Injuries
• a. swelling of spinal cord tissue can
result in temporary loss of nerve
function
• b. if spinal cord is severed, you may
become paralyzed.
• http://www.youtube.com/watch?v=DCyG7xH9C98
Problems of the Nervous
System
• 4. Meningitis – inflammation of the
spinal and cranial meninges caused by
a virus or bacteria
• a. symptoms include fever, headache,
light and sound sensitivity, and neck
stiffness.
• b. can result in death
How to care for/prevent these
problems:
• 1. Eat a well-balanced diet, exercise
regularly, get lots of sleep!
• 2. Wear protective devices – helmet,
seat belt
• 3. Stay away from drugs and
alcohol!!!
Nervous System
PNS
Somatic
CNS
Autonomic
Cerebrum
Sympathetic
Spinal
Cord
Brain
Brain Stem
Cerebellum
Parasympathetic
Pons/Medulla/Hypothalamus/Midbrain/Thalamus