Module 6: The nervous system and the endocrine

system

Identify and describe the functions of the parts of a neuron

Explain the process of neural transmission Explain the roles of neurotransmitters in the

neural transmission Identify and describe the divisions of the

nervous system Discuss the nature and the function of the

endocrine system communication

Learning goals:

Neurons: the building blocks of the nervous system(biology review) Nervous system is electrochemical

communication system Neurons-a nerve cell; basic building block of

the nervous system Example:brain, spinal cord, and nerves Neuron used for 3 tasks1. Receive information(form of electrochemical

impulses2. Carry information down its length3. Pass information on to the next neuron in line

Behavior thought and emotion you’ve experienced is dependent on the ability of the neuron to process information(ability to do 3 steps)

Fire or not fire Dendrites- branching extensions of a

neuron that receive information and conduct impulses toward the cell body

Soma-the cell body of a neuron which contains the nucleus and other parts that keep the cell healthy

Axon-the extension of a neuron through which neural impulses are sent

length of axon is dependent upon location Example brain VS leg Longer axons covered by myelin sheath that

protects the axon and speeds up the transmission of information

axon terminals-the endpoint of a neuron where neurotransmitters are stored

Neuron firesAction potential-a neural impulse;a brief

electrical charge that travels down the axon of a neuron

Refractory period-the “recharging phase” during which a neuron after firing can not generate another action potential

Example camera flash resting potential-the state of a neuron when

it is at rest and capable of generating an action potential

How do neurons communicate

All-or-none-principle that states that if a neuron fires it always fires at the same intensity;all action potentials have the same strength

Example toilet http://www.funnypicturefunnyphoto.com/

funny-picture-photo-toilet-mural-dark-mephi.jpg

Doesn’t necessarily need 2 neurons to meet Synapse-the tiny, fluid filled gap between

the axon terminal of one neuron and the dendrite of another

Neurotransmitter-a chemical messenger that travels across the synapse from one neuron to the next and influences whether a neuron will generate an action potential

When action potential works towards end of neuron it causes the release of neurotransmitters from the axon terminals

Communication between neurons

Neurotransmitters have unique shapes and rapidly cross the synapse and fit into receptor sites on the dendrite

Neurotransmitters can come to rest only in receptor sites designed to fit the their shape. Once in side can serve as 2 functions:

1. excitatory factor-a neurotransmitter effect that makes it more likely that the receiving neuron will generate an action potential or fire

2. inhibitory factor-a neurotransmitter effect that makes it less likely that a receiving neuron will generate an action potential or fire

Example just do it or red light

Think of a radio station? What is the steps to hearing a song on the radio

Receptor cells-(antenna) specialized cells in every sensory system of the body that can turn other kinds of energy into action potentials(neural impulses) that the brain can process

Examples light and sound sensory nerves- carry information from the

sense receptors to the spianal cord and brain Interneurons- nerve cells in the brain and spinal

cord responsible for processing information

Neural chain

Senosry information enters the body through receptor cells

Brain processes the sensory info and decides what to do

Motor nerves receive commands from the brain and react

Brain determines when action is necessary to deal with incoming information

Brain determines course of action To trigger actions the brain must get word

to the body’s muscle Motor nerves-nerves that catrrty

information away from the brain and spinal cord to the muscles and glands

2 major components:1. Central nervous system(CNS)-brain

and spinal cord2. Peripheral nervous system(PNS)-

contains all sensory nerves and motor nerves that connect the brain and the spinal cord to the rest of the body

CNS is encased in bone for protectionInterneurons are responsible for processing

information

Structure of the nervous system

PNS divides into 2 systems:1. Somatic nervous system- division of the

peripheral nervous system that controls the body’s skeletal muscle

Example-develop idea to walk across the classroom, CNS commands -> somatic nervous system commands legs to move

2. Autonomic nervous system-division of the peripheral nervous system that controls the glands and muscles of the internal organs.

PNS

sympathetic nervous system- the part of the autonomic nervous system that arouses the body to deal with perceived threats

Fight or flight responseParasympathetic nervous system-calms

the body down

Subdivisions of autonomic nervous system

Besides nervous system, endocrine system is another way for communicating

Slower communicating system Endocrine system-one of the body’s 2

communicating systems; a set of glands that produce hormones, chemical messengers that circulate in the blood

Hormone-chemical messengers that circulate throughout the body in the blood

Endocrine system

Hormones and neural transmitters are similar

Carry and communicate messages to receptor sites

Pituitary gland- “master gland” controls endocrine glands

Connected to hypothalamus Work together to monitor levels of glucoseand insulinThyroid, adrenal glands examples

cont

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