Topic 8.3 Nervous Coordination and Regulation

8.3.1 List the main functions of the nervous system i.e. receive, coordinate, and respond to information.

8.3.2 Differentiate between the terms stimulus, receptor, impulse, and effector.

8.3.3 Describe the importance of the nervous system in maintaining homeostasis within the human body.

Topic 8.4 The Neuron

8.4.1 Describe the function of the neuron.

8.4.2 Identify from a model or diagram and describe the function of the structures of a neuron:

cell body dendrites axon schwann cell (myelin) node(s) of Ranvier neurilemma

8.4.3 Differentiate between sensory, motor, and mixed nerves.

8.4.4 Illustrate and explain the function of a reflex arc using an example.

8.4.5 Demonstrate some human reflexes and measure reaction rates.

8.4.6 Explain how a nerve impulse is transmitted through a neuron using the following terms:

resting potential sodium-potassium pump action potential refractory period threshold all-or-none response

8.4.7 Explain how the nervous system distinguishes between stimuli of different types and strengths

8.4.8 Describe the transmission of a nerve impulse across a synapse.

8.4.9 Discuss the effects of psychoactive drugs and neurotoxins on synaptic transmission.

Topic 8.5 The Nervous System

8.5.1 Differentiate between the central nervous system and peripheral nervous system. Page 391

8.5.2 Describe the functions of the following structures of the C.N.S. brain spinal cord meninges gray matter white matter cerebrospinal fluid

Page 391

8.5.3 Describe the function of the following structures of the C.N.S. cerebrum (related lobes - frontal, temporal, parietal, occipital) cerebellum corpus collosum medulla oblongata pons thalamus hypothalamus pituitary gland

Pages 391 - 396

8.5.4 Differentiate between autonomic and somatic nervous systems. Pages 396- 397

8.5.5 Explain how the sympathetic and parasympathetic divisions of the autonomic nervous system contribute to homeostasis. Pages 397 - 398

Topic 8.6 Disorders of the Nervous System and Endocrine System

8.6.1 Describe the cause, symptoms, and treatment of three of the disorders related to the following hormones:

STH (giantism, acromegaly, dwarfism) Pages 362 - 363 cortical, aldosterone (Cushing's disease, Addison's disease) thyroxine (hyperthyroidism, goiter, hypothyroidism, cretinism)

P. 361 - 362 insulin (hypoglycemia, hyperglycemia, diabetes meilitis) Page 365

8.6.2 Discuss the effects of anabolic steroid use on the body.

semicircular canals auditory nerve

8.6.3 Describe the cause, symptoms, and treatment of five of the following disorders of the nervous system: (Page 399 italisized foundKunderlined — part of the study of the eye)

multiple sclerosis deafness Alzheimer's disease meningitis astigmatism motion sickness

Huntington's chorea color blindness motion sickness Parkinson's disease cerebral palsy dyslexia gleucpma 0119191;11 myopia hyperopia

8.7 Topic Sensory Receptors

.1 List and describe the stimulus detected for the different sensory

receptors present in the human body

8.1 .2 Identify the following parts of the eye from a model, diagram, or

specimen and describe the function:

sclera choroid iris lens retina,cillary muscles cornea

aqueous humor vitreous humor puplU optic nerve 8.7

.3 Explain the process of vision in humans, including the role of rods

and cones.

.4 Identify the following parts of the ear from a diagram, model, or

specimen and describe their function:

pinna ossicles oval window,vestibule cochlea

auditory canal tympanic membrane eustachian tube

Sensory neurons Sensory neurons

Motor neurons

External Environment

> Motor neurons

SO matic nervous system

Autonomic nervous system

Human Nervous System

CNS PNS

• Brain & Spinal Cord • Intemeurons

= Everything else = Sensory & Motor Neurons

SNS

ANS

• Voluntary • Input from external sense organs • Output to skeletal muscles = Motor and Sensory Nerves = Cranial — to & from brain - Spinal — to & from spinal cord

• Involuntary • Input from internal receptors =, Output to smooth muscles and glands • Motor and Sensory Nerves

Sympathetic NS

• Flight or Fight Response • Speed functions up

Parasympathetic NS

6 Rest & Digest Response • Slow functions down

The Nervous System r octr

A) Main Functions of the Nervous System:

, Reception: Collection and conduction of information about the environment to the central nervous system. (Receiving stimuli)

z Interpretation: Translating the information into context, based on experience. (Switch board) - P ra.ti on Sorting: Deciding what information is high priority and what can be ignored. (Switch board) Transmission: Sending out messages to cause a reaction in response to the received information. (Response)

B) Parts of the Nervous System:

I, Central Nervous System (CNS): brain and spinal cord (controls the activities of the body).

,Z. Peripheral Nervous System (PNS): nerves that extend beyond the spinal cord and the brain.

,9 Autonomic Nervous System (ANS): controls all involuntary activities of the body. (eX. 1\e4.4-1- beck-t- +- r e\ sf I r-c7L-tx k) )

9 So 044,-t-l‘c. N ed. vovt...t Ckl..‘ Cs N &,) . tfr-D I s c4.11 v 0 ILL in+0.1,-, j a....e._1-1vics ( e...X. wa-Lk: A.5 -t- s;uAl)

C) Neurons (3 types): A neuron is a nerve cell. When many neurons (nerve cells) are

bound together, it is called a nerve. Neurons are specialized to carry nerve impulses to and from the CNS. The size of a single neuron can be less than lcm or greater than lm.

Sensory Neurons: (?.r t °E tLe-- ?S 0 - send impluses from receptors to association neurons in CNS - can regenerate (due to having a neurilemma ok.1 so b-,1 -e- 1, r■ - cell body on the side -attached to skin, eye, ear, nose, and taste bud receptors

- located in CNS -00A ° kw:1w 0 a" rn+er-vve- o I- Re ( 0-j httkr-0,14) Association Neurons: ( I

- send impluses from sensory neurons to motor neurons - cannot regenerate Lao, ti-- ii,.._.,,.... h e..v..r t:tc try-v...0k, or Motor Neurons: ( e(krf of {-Le. f NO - send impulses from association neurons to muscles, organs, or glands Ce4e-c--1-G is s) - can regenerate (due to having a neurilemma 0,1/41 so /.., eV,o,

Saw.

impidse_s)

L RECEPTION)

Defection by ex terrui

;enw or/ans

ITRANSMISSIONI

Sensory (afferent) neurons transmit information

ECEPTION__,

Oeteceon by ;titer:lit sense organs(sectettcs)

r TRANSMISSION I

Sensory Iarterenti neurons te3f1Srnit InfOrMICK3n Cv

ITRANSMISSION

ITRANSMISSION 1

Efferent neurons transmit imOutles

out appropriate action icy. respiration rate increases: heart rate increaset Wood pressure tiara

Figure 39-1 Flow of information through the nervous system.

Motor leiferent) naurons transmit impulses

1 RESPONSE

Effectors carry out appropriate action.

• leg. animal runs surly,

-rruiL.1

(e.g. viCr.g:on, ...movement, :e bf000 pH. thane iighcodor)

in blood pressure)

CENTRAL NERVOUS SYSTEM

arlin and spinal cord

(ir..forrra don entworeted .seasort!sii rtspor.se initiated)

Are

Figure B-12 SENSORY NERVE ENDINGS IN THE SKIN

touch touch pressure heat pain cold

nerve endings Meissner's

Pacinian

Ruffini free nerve

Krause on hair root

corpuscles corpuscles

corpuscles endings end bulb

, 1/ 1-4

OLL

Copyright" 1987 John Wiley & Sons Canada Limited

Anatomy of a Neuron

Cell body: a mass of neuroplasm (cytoplasm) at the top of a neuron containing a nucleus and dendrites.

Dendrites: extensions of the cell body that receive nerve impulses from another neuron and direct them towards the cell body.

Axon: a long shaft of a neuron that extends away from the cell body. It takes nerve implulses away from the cell body and to the next neuron or affector. (may or may not have a myelin sheath).

Schwann cell: a cell that raps around the axon (like a jelly-roll) and secretes the myelin sheath.

Neurilemma: a membrane surrounding the myelin sheath in motor and sensory neurons, providing the ability to regenerate and repair the neurons. (not present in association neurons)

Myelin Sheath: a white fatty substance that surrounds the axons of motor and sensory neurons and acts as insulation to prevent ion loss and to increase the speed of nerve impulse travel.

Node of Ranvier: a gap in the myelin sheath which serves to give a boost to a passing nerve impulse. It does this by allowing the impulse to escape and jump across portions of the axon.

Sensory neuron Interneuron Motor Neuron

Length of Long dendrites and short i Short dendrites and either a Short dendrites and long Fibers axon Ishort or long axon axon

Mostly inside the PNS Mostly inside the PNS (only I Location (only the synaptic endings

are inside the CNS) Entirely within the CNS the dendrites are inside the

CNS)

Myelinated Yes No Yes

Cell Body At side of neuron tAt end of neuron At end of neuron

Capable of Regeneration Yes No Yes

Conduct impulse from Conduct impulse from a Conduct impulse from an Function sensory receptors to I sensory neuron to the interneuron to an effector

interneurons in the CNS jappropriate motor neuron (muscle or gland)

A neuron has a cell body with extensions leading off it. Numerous dendrites provide a large surface

area for connecting with other neurons, and carry nerve impulses towards the cell body. A single long

axon carries the nerve impulse away from the cell body. The axon is only lOpm in diameter but can be up

to 4m in length in a large animal (a piece of spaghetti the same shape would be 400m long)! Most

neurons have many companion cells called Schwann cells, which wrap their cell membrane around the

axon many times in a spiral to form a thick insulating lipid layer called the myelin sheath. Nerve impulses

can be passed from the axon of one neuron to the dendrites of another at a synapse. A nerve is a

discrete bundle of several thousand axons. A ganglion is a bundle of cell bodies.

There are several differences between axons and dendrites:

Axons

• Take information away from cell body

• Smooth Surface

• Generally only 1 axon per cell body

• Not in contact with the synapse

• May have myelin & Schwann cells

• Branch further from the cell body

• Positioned in centre of the neuron

• Usually longer length than dendrites

• Directs impulse towards the next neuron

• Bring information to the cell body

• Rough Surface (dendritic spines)

• Usually many dendrites per cell body

• In contact with the synapse

• Most have no myelin or Schwann cells

• Branch near the cell body

• Positioned at end of neuron

• Usually shorter length than axons

• Directs impulse towards the cell body of the

same neuron

Schwann node of Ranvier

cells myelin sheath rece 10r5 cell body

Motor Neuron

motor end plates on muscle fibers

axon

nu Cl eus synaptic endings

4 Sensory Neuron

cell

body

dendrite s.

-axon Sensors receptors

node of Ranvier

dendiptes

cell body

axon

sraptic endings

myelin sheath

3 Types of Neurons

4. Also known as art Association Neuron or Relay Neuron

Nruu t\1

,

)2.

3 T/FeS letitorys

ER Otis C C L IONAL

taTo RO ?Mgt)

OTOTTgOU @0?0

' CNS PNS

Axon branches

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Priis

CNS PNS CI ;

SO Dn. AX0111 WOTTCX? (ME

e@l2,11

PIA ctr' E

CNS PNS r

P

Smooth

G (effector) muscle AUTONOMIC

GANGUON

E00 -)r

al:X0g06) USgg'2@g F

FO@VCealapah0 0 ft) O@ (NEODOC)69 G

PRE CAN Zr IVO iv) AUTO MO 0 R DCY

CNS

Gray -,- rnatter,•

White matter

tiO)/4

Wctg. rAlf@GMg

co Mterneurons are found mostly in the CNS. They make up the bulk of the neu-rons of the brain and spinal cord. They come in a variety Of shapes and sizes. Many of them are dirpntiv rp•W.,-1 - - • •

131

Etlf?Orli See 11

CENTRAL NERVOUS SYSTEM

(CNS)

PERIPHERAL NERVOUS SYSTEM (PNS)

AFFERENT (maw) NeuRoss -Ext.emal muti

Somatic or visceral Receptor

Visceral (Autonomic) t Smooth

—a. (Muscle effectors)

Spinal cord (or brain)

Somatic 4 J s",setal EFFERENT MOTO") Neuman

■-■■■•

CM Use light colors throughout the plate. Do not color the summary diagram at the top of the page until completing the rest of the plate_

Neurons generally function in one of three modes: they conduct impulses from receptors in the body to the central nervous system or CNS (sensory

I- or afferent neurons); or they conduct motor command impulses from the CNS to muscles of the body (motor or efferent neurons); or they form a network of interconnecting neurons in the CNS-between motor and sen-sory neurons (interneurons). If the sensory or motor neurons relate to muscuioskeletal structures or the skin and fascia, the prefix "somatic" may be applied (somatic afferent/somatic efferent). If these neurons are related to organs with hollow cavities (viscera), the prefix "visceral" may be applied (visceral afferent/visceral efferent).

Rocess)

Pagn g36/09 GA@Ce C3igCX0

OPOOgaCW, P @Alga 00CNic 622M

0§Z`UTI P2

Sensory neurons conduct impulses from sensory receptors to synapses in the CNS. The receptors may be sensitive to touch, pressure, pain, joint position, muscle tension, chemical concentration, light, or other mechanical stimulus, basically providing information on the external or internal environ-ment and related changes. Sensory neurons are unipolar neurons with cer-tain exceptions, and are characterized by peripheral processes ("axons"), cell bodies. and central processes ("axons").

PER

Skeletal

Attli rel

muscle (effector) "I

50 An T

MOTOR

Motor neurons conduct impulses from cell bodies located in the CNS, through axons that leave the CNS and subsequently divide into branches, each of which becomes incorporated into the cell membrane of a muscle cell (motor end plate). Here the neuron releases its neurotransmitter that induces the muscle cell to shorten.

Autonomic motor neurons function as paired units connected at a ganglion by synapse. The first or preganglionic neuron arises in the CNS, and its axon embarks for a ganglion located some distance from the CNS. There it syn-apses with the cell body or dendrite of a postganglionic neuron whose axon proceeds to the effector organ: smooth muscle, cardiac muscle, or glands.

o

I Part,Otlft6:tieuron that releases ri*OltAilsrnitters- into the synaptic cleft.

am**the myelin sheath.

tv.

2. Fatty niatC - 't surrounds sorrig:azons.

Answer 1*".

5. Part ofueurotP the ..nucleus

_

*neuron that contains genetic material.

NeurOscienee-for Kids - Parts of a Neuron Review http://faculty.washington.edu/chudier/reveell.htmi

MParts of a Neuron Review '

Here is a short review about the parts of a neuron. Take a look at this figure and then answer the questions. The numbers on the figure correspond to the number of the question. To see the answers, click on the "answer" button.

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5/12/00 2:04 PM ,

Compare and Contrast Frame

Unit Ce-kevi.*rx_t t1/4)(2XvoLLS rr+ Topic 1•,..)Q.A.A.r.o YIS

How are FjXOM and Depa 4-ec

alike?

How are Pt xo and different?

Write a statement to compare and contrast the two terms, concepts, or events.

Compare and Contrast Frame: Used by permission of Lynda Matchullis and Sete Mueller, Nellie McClung Collegiate, Pembina Valley S.D. No, 2.7.

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