The Nervous System Coordinates all the body’s activity
Dec 14, 2015
The Nervous SystemCoordinates 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
consciousnesshttp://www.youtube.com/watch?v=Tyv4du7BTOc
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
CNSPNS
SomaticAutonomic
SympatheticParasympathetic
Brain Spinal Cord
Cerebrum Brain Stem Cerebellum
Pons/Medulla/Hypothalamus/Midbrain/Thalamus