Name: ______Date: ______Class: ______Page 9/9

UNIT PACKET FOR The Nervous System

kMA Frameworks:

MA LS 4.4 Explain how the nervous system (brain, spinal cord, sensory neurons, motor neurons) mediates communication between different parts of the body and the body’s interactions with the environment. Identify the basic unit of the nervous system, the neuron, and explain generally how it works.

MA LS 4.7 Recognize that communication between cells is required for coordination of body functions. The nerves communicate with electrochemical signals, hormones circulate through the blood, and some cells produce signals to communicate only with nearby cells.

MA LS 4.8 Recognize that the body’s systems interact to maintain homeostasis. Describe the basic function of a physiological feedback loop.

28.1 – The nervous system links sensation to response

28.2 – Neurons conduct nerve impulses

28.3 – The PNS carries information to and from the CNS

28.4 – The CNS integrates nervous information

28.5 – Sensory receptors link the environment to the nervous system

OBJECTIVES:

Put on your review sheet:

1.  Differentiate between sensory neurons, interneurons, and motor neurons.

2.  Differentiate between the central nervous system and the peripheral nervous system

3.  Differentiate between the autonomic and somatic nervous systems

4.  Identify and give the functions of the three main regions of the brain (Cerebrum, Cerebellum, Brainstem)

5.  Describe the functions of the right and left hemispheres of the cerebrum.

6.  Identify the function of the hypothalamus

7.  Define homeostasis

Be able to do by practicing:

8.  Match each of the key terms to its correct definition

9.  Given a picture of a neuron, diagram the path of a nerve impulse

10.  Label the main parts of the brain on a diagram

11.  Label the parts of a neuron on a diagram

12.  Solve a problem similar to the activity we did in “the brain and its functions.” Given parts of the brain and the areas of the body they govern, tell what might happen to the body if certain parts of the brain were damaged. (You will be given all of the information, you will just have to know how to use it)

KEY TERMS:

28.1 – The nervous system links sensation to response

Central Nervous System (CNS): the body’s primary information processing system; includes the brain and spinal cord

Interneurons: nerve cell located entirely in the central nervous system that integrates sensory information and sends motor commands

Motor Neuron: nerve cell that carries signals from the central nervous system to muscle or gland cells.

Neuron: nerve cell; basic unit of nervous tissue

Peripheral Nervous System (PNS): network of nerves carrying signals into and out of the CNS.

Reflex: rapid, automatic response to a stimulus

Response: reaction to an event

Reflex Arc: The nervous system pathway that regulates a reflex

Sensory Neuron: nerve cell that carries information from the environment to the CNS

Stimulus: environmental change that triggers a reaction

28.2: Neurons conduct nerve impulses

Axon: neuron fiber that carries electric impulses away from the cell body and toward other cells

Dendrites: neuron fiver that receives signals and carries them toward the cell body

Myelin sheath: thick coat of material that surrounds and insulates the axon of some neurons

Node: the spaces on an axon between the myelin

Neurotransmitter: chemical that carries information from one neuron to another or to another cell

Synapse: where two neurons meet and electrical or chemical signals are relayed between the two

28.3:The PNS carries information to and from the CNS

Autonomic Nervous System: carries signals to internal organs

Somatic Nervous System: carries signals from the CNS to skeletal muscles

28.4:The CNS integrates nervous information

Brainstem (medulla): lower section of the brain that filters information going to and from the brain
Cerebellum: part of the brain located below the cerebrum and above the spinal cord; planning center that coordinates body movement.

Cerebrum: largest and most complex part of the brain, made up of the left and right hemispheres

Homeostasis: internal stability

Hypothalamus: portion of the brain that maintains homeostasis of the body



NOTES: 28.1 – The nervous system links sensation to response

Structure and Functions of the Nervous System

·  Basic unit: Neuron (nerve cell)

·  Parts of the nervous system:

o  CNS: Central Nervous System

§  Made of brain and spinal cord

o  PNS: Peripheral Nervous System

§  Made of all nerves outside of the CNS.

Flow of Information in the Nervous System

·  Sensory Input: the PNS receives information about environmental change (stimulus), then sensory neurons carry the information from the PNS to CNS.

·  Integration: the CNS interprets the information sent from the PNS

o  Involves neurons located entirely within the CNS, called interneurons.

·  Motor Output: the CNS orders a response

o  Neurons that carry such signals away from the CNS are called motor neurons.

Reflexes

·  A reflex is an automatic response

·  The nervous system pathway that regulates a reflex is called a reflex arc.

·  Example: During a physical, your doctor has probably performed a test by striking your knee with a rubber hammer. Without thinking about it, your lower leg quickly jerks forward – a reflex.

Example of A Reflex Arc


NOTES: 28.2 - Neurons conduct nerve impulses

Neurons

•  Neurons are the specialized cells that transmit information around the body.

•  They are the basic unit of the nervous system

Structure of a Neuron

•  Dendrites: receive signals and carry them toward the neuron’s cell body

•  Axon: a fiber that carries electrical impulses away from the cell body and toward other cells

•  Axon terminals: play a role in transmitting information to other cells

•  Myelin sheath: insulates the axon, allows signal to travel down the axon faster.

Types of Neurons

•  Sensory Neurons: bring impulses toward spinal cord and brain

•  Interneurons: interpret information sent to brain and spinal cord

•  Motor Neurons: bring impulses away from brain and spinal cord

Synapse

•  Synapse: space separating the axon of one neuron from the dendrite of another

•  At end of axon there are vesicles filled with a chemical called a neurotransmitter. This is the chemical that neurons use to communicate with each other.

Conduction of Impulse

•  When there is a stimulus, the impulse moves from the dendrites to the axon terminals.

•  When the stimulus occurs, there are 2 options:

•  Neuron fires if there is a large enough stimulus

•  Neuron does not fire if the stimulus is too small.

•  “All or none” response – neuron either fires or it doesn’t.

•  If neuron fires, impulse travels to other neurons across synapse by release of neurotransmitters.


The Nervous System (CNS and PNS)

What is the Nervous System?

·  The nervous system is a complex network of cells that communicate with one another

·  It controls mental and physical activity and contributes to homeostasis

Two Main Parts:

·  Central Nervous System (CNS)

o  Made of the brain and spinal cord

o  3 major divisions of the brain

o  Cerebrum

§  Has right and left hemispheres

§  Right: recognition of faces, spatial relations

§  Left: understanding of words, grammar, structure of language

§  Body’s left side is controlled by the right side of the cerebrum and the right side is controlled by left.

o  Cerebellum

§  Controls balance, movement, posture, and coordination

o  Brainstem

§  Connects brain to spinal cord

§  Controls reflexes

§  Regulates heart beat, breathing, and digestion

§  Aides in balance & blood pressure

§  Made up of the:

§  Midbrain

§  Pons

§  Medulla Oblongata

·  Peripheral Nervous System (PNS)

o  Made up of all of the nerves

o  Contains the Autonomic Nervous System, which regulates involuntary functions (digestion, heartbeat, glands, etc.)

§  ANS is made up of the:

·  Sympathetic NS: controls body during emergency or major stress (“fight or flight”), and during intense activities that consume energy (running, taking a difficult exam, etc.)

·  Parasympathetic NS: controls body during normal conditions, calms body and returns it to regular maintenance functions

Name: ______Date: ______Class: ______

Parts of the brain and their functions

Identify which part of the brain controls each of the following functions:

Cerebrum / Cerebellum / Brainstem / Hypothalamus
Controls logical thinking
Filters information going to / from brain
Regulates body temperature
Evaluates body positioning
Controls breathing
Regulates hunger
Controls language
Coordinates body movements
Controls creative thoughts
Regulates sleep

28.3 – The PNS carries information to and from the CNS

Use your textbook to find the answers to the following questions:

1.  What are the two divisions of the PNS?

2.  What are the functions of the two sets of sensory neurons in the Peripheral Nervous System?

3.  What does the motor division of the Peripheral Nervous System do?

4.  What are the two systems that are part of the motor division of the PNS and what is the job of each?

5.  Draw a diagram below that relates ONLY the following five terms: Somatic nervous system, sensory division, autonomic nervous system, motor division, peripheral nervous system

6.  List five actions within the body that the autonomic nervous system controls.

28.4 – The CNS integrates nervous information

Use your textbook to find the answers to the following questions:

7.  What are the two structures that make up the CNS?

8.  What are the three jobs of the spinal cord?

9.  What is the largest part of the brain?

10.  The left side of the brain controls movement of the ______side of the body, and it specializes in ______, ______, and ______.

11.  The right side of the brain controls movement of the ______side of the body, and it is responsible for ______, and ______.

12.  The two brain hemispheres are connected by a thick band called the:

13.  The cerebrum is divided into many lobes that have different functions. What are three things that the brain controls?

14.  What does the cerebrum do?

15.  What does the brainstem regulate and control?

16.  What does the hypothalamus do?