The Nervous System

Jacqueline Immello, Stephanie Pantano, Shaakira Parker and Anthony

Patti

What is the nervous system?

• The nervous system’s main role is controlling and communicating. This system is where all mental activity takes place.

• It works with the endocrine system in order to regulate and keep homeostasis.

• Often referred to as the body’s control center.

• The nervous system is made up of the brain, spinal cord, and nerves that are located throughout the body.

The Central Nervous SystemThe central nervous system contains

the brain and the spinal cord.

The Brain (Encephalon)

• The brain controls everything the body does

• It is the center of the nervous system

• Forebrain - Cerebrum– Largest portion o the brain (85%)– Controls voluntary muscle movement– The cerebral cortex is the part of the

brain responsible for intellectual functions such as thinking, reasoning, and storing short and long term memory

• Midbrain– Connects higher and lower brain functions

– Body movement– Contains the pleasure center which has to do with the development of addictive behaviors

• Hindbrain– Cerebellum

• controls balance, coordination and movement

– Brain Stem• Connection between the brain and the spinal

chord• Controls the involuntary muscle movement

like breathing, digestion, circulation, etc.• Also sorts messages that are sent to the

brain

The Spinal Cord (Medulla Spinalis)

• The spinal chord, which is made up of nervous tissue and support cells, runs down the middle of the back from the brain to the coccyx (or tailbone)

• Protected by cerebral spinal fluid and the vertebra.

• There are 31 pairs of nerves arranged along the spinal cord.

• The spinal cord is made up of nerve fibers which transfer messages to parts

of the body and the brain– Motor signals travel down the cord– Sensory signals travel upwards

Peripheral Nervous System

• The peripheral nervous system extends out of the central nervous system with nerves.

Neurons• Any of the impulse-conducting cells that constitute the brain, spinal column, and nerves.

• Also known as nerve cells.• Function in receiving and transmitting signals along the aforementioned structures.

Structure of Neurons • Dendrites- highly branched extensions that receive signals from other neurons.

• Axons- extensions which are much longer than dendrites. Transmit signals to other cells. The cells that receive these signals may be neurons or effector cells (muscle or endocrine cells).

• Mycelin Sheath- covers an axon for insulation of electrical current. Consists of Schwann cells.

• Synaptic Terminals- located at branched ends of the axon.

• Synapse- site of communication between a synaptic terminal and another cell.

• Presynaptic and Postsynaptic neurons- The transmitting and receiving neurons.

Neuron Structure and

Communication

• Neurotransmitter (a substance contained in the synapse) binds to and opens gated ion channels (labeled receptors).

• Na+ and K+ then diffuse through the channel.

Synapse

Neuron Function in Information Processing• 3 stages of information processing: sensory

input, integration, and motor output.

• Sensory Input: Sensory Neurons - transmit information from sensors that detect external stimuli and internal conditions.

• Integration: Interneurons - integrate (analyze and interpret) sensory input.

• Motor Output: Motor Neurons – communicate with effector cells. Produce reflexes (automatic responses to stimuli) in the simplest circuits.

Peripheral Nervous System

• This system is further divided into the somatic and autonomic nervous systems.

Somatic Nervous System

• Reception of an outside influence:- touch, hearing, sight

• Voluntary control of the body movements through skeletal muscle

• When stimulated, the response of the nerves is the response arc

Autonomic Nervous System

• Regulates the involuntary organs within our body such as the heart and stomach, muscles, and glands.

• Important in emergencies when undergoing stress and also in regular situations like digestion and rest.

• Can be subcategorized into the sympathetic, parasympathetic, and enteric nervous systems

Sympathetic Nervous System

• "Fight or Flight" responses in the face of danger

• Blood pressure increases, your heart beats faster, and digestion slows down.

• In the sympathetic nervous system the synapse, ganglion uses acetylcholine as a neurotransmitter.

• The synapse of the post-ganglionic neuron with the target organ uses the neurotransmitter norepinephrine.

Sympathetic Nervous System

Parasympathetic Nervous System

• "Rest and Digest" responses• Blood pressure decreases, the heart beats slower, and digestion can start

• This synapse uses the neurotransmitter called acetylcholine.

Parasympathetic Nervous System

Enteric Nervous System

• sends and receives impulses, records experiences and respond to emotions.

• located in the tissue lining the esophagus, stomach, small intestine and colon.

• the neural crest is formed in the early stages of the embryo. – One section turns into the central nervous system.

– Another piece migrates to become the enteric nervous system.

Activities

Label parts 1-3 and list their function in the nervous system

List the names of the sections highlighted in red, blue, and green

Central Nervous System Crossword

Peripheral Nervous System

Fill in the Blanks

Word Box

• cranial nerves• voluntary• peripheral nervous system

(PNS)• central nervous system

(CNS)• spinal nerves• peristalsis• homeostasis• neurotransmitter• somatic nervous system

• enteric division• parasympathetic division• voluntary• involuntary• internal • sympathetic division• postganglionic• preganglionic• autonomic nervous system

The 1 is involved in regulating a vertebrate’s movement and internal environment. The PNS sends information to and from the ____2__ . The 3 , which starts in the brain and ends in the head and upper body, and the 4 , which come from the spinal cord and branch to parts of the body below the head, are the left and right parts of the peripheral nervous system. They both have sensory and motor neurons. The PNS is divided into two systems that help to maintain 5.

The 6 transmits signals to and from the skeletal muscles and is 7 because it is consciously controlled by the reflexes. The other system is the 8

. It controls smooth and cardiac muscles, and the organs of the digestive, cardiovascular, excretory, and endocrine systems, which helps to regulate the 9 environment. The autonomic nervous system has 10 control. It is divided into three parts.

The 11 has to do with a “flight or fight” response or the arousal and energy generation. It performs actions such as stimulating glucose release from the liver, relaxing bronchi in lungs, accelerating the heart, etc. Another division is the 12 , which is the “rest and digest” because it causes responses of calm and a return to self maintenance functions. This division performs actions such as the slowing of the heart, promoting emptying of bladder, stimulating activities of the stomach and intestines, etc.

Both the parasympathetic and sympathetic divisions have 13 . They are released by 14 and 15 neurons. Acetylcholine and norepinephrine are two types of neurotransmitters. The last division is called the 16 , which consist of neurons in the digestive tract, pancreas, and gallbladder that control the organs’ secretions and activities in the smooth muscles that produce 17 . This division is regulated sympathetic and parasympathetic divisions.

Answer Key

Brain Activity answers1. Cerebrum – voluntary muscle movement,

thinking, reasoning, and storing short and long term memory

2. Cerebellum - controls balance, coordination and movement

3. Brain Stem - sorts messages that are sent to the brain and controls involuntary muscle movement

Red - ForebrainBlue - MidbrainGreen - Hindbrain

Crossword Answers

Fill in the Blank Answers

• 1. Peripheral Nervous System

• 2. Central Nervous System• 3. cranial nerves• 4. spinal nerves• 5. homeostasis• 6. Somatic Nervous System• 7. voluntary• 8. Autonomic Nervous

System

• 9. internal• 10. involuntary• 11. sympathetic division• 12. parasympathetic• 13. neurotransmitters• 14. preganglionic• 15. postganglionic• 16. enteric division• 17. peristalsis

Websites• http://faculty.washington.edu/chudler/auto.html

• http://www.apparelyzed.com/spinalcord.html

• http://kidshealth.org/kid/htbw/brain.html#

• http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookNERV.html

• http://www.innerbody.com/image/nervov.html

• http://yucky.discovery.com/flash/body/pg000136.html

• http://www.psyking.net/id36.htm