Chapter 20 - Coordination in Mammals (Part 1)

7/30/2019 Chapter 20 - Coordination in Mammals (Part 1)

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CHAPTER 20

COORDINATION

20.1 NERVOUS SYSTEM


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SUB-TOPIC

20.1 Nervous system

20.2 Mechanism of muscle contraction20.3 Hormones in mammals

20.4 Hormones in plants


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OBJECTIVES

(a)Describe the organization of the nervous

system.

(b)Explain the general role of the sympathetic

and parasympathetic nervous system.

(c) Explain the generation of action potential,transmission and characteristic of nerve

impulse along an axon.


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OBJECTIVES

(d)Describe the structure of synapse and

explain the mechanism of synaptic

transmission across synapses.

(e)Compare the transmission of impulse at the

synapse and along the axon.

(f) Explain the mechanism of action of drugs on

the nervous system.


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The basic unit of the nervous systemneuron

Dendrites receive stimuli

Nerve cell body

@ nucleus transmits thestimuli

Axon transmits the impulse toanother dendrite

PRIOR KNOWLEDGE :


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Sensory neurons or receptors receive a stimulus from:

ears - hearing

eyes - sight

nose - smell

skin - touch

mouth - taste

PRIOR KNOWLEDGE :


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Can be found inside my head. Makes my body work.

Makes me think and feel.

Makes sure our hearts keep beating and our

lungs keep working without us having to think

about it.

Part of it makes our muscles work. The biggestpart of it makes us think, see, hear, feel and taste.

Answer:

Brain

PRIOR KNOWLEDGE :

What is it?


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We each have a backbone, called a spine.

It can be found in the spine.

It joins the brain at the top of our neck.

All through our body there are nerves which connectto it. This is called the nervous system.

Messages from the nerves travel to it, which sends

them to the brain. Neurons are long, wiry cells that carry

electrical messages through the nervous system and thebrain.

Answer:

Spinal cord

PRIOR KNOWLEDGE :

What is it?


9/46The Nervous SystemThe Nervous System

THE ORGANIZATION OF

THE NERVOUS SYSTEM


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The Nervous SystemThe Nervous System

THE ORGANIZATION OF THE

NERVOUS SYSTEM

Central NervousSystem (CNS)


Peripheral NervousSystem (PNS)



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Central Nervous System(CNS)


BrainBrain Spinal CordSpinal Cord

Peripheral Nervous System (PNS)Peripheral Nervous System (PNS)


THE ORGANIZATION OF

THE NERVOUS SYSTEM


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THE ORGANIZATION OF

THE NERVOUS SYSTEM


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SensoryNeurons

SensoryNeurons

Motor NeuronsMotor Neurons


THE ORGANIZATION OF

THE NERVOUS SYSTEM


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Sensory NeuronsSensory NeuronsMotor NeuronsMotor Neurons


THE ORGANIZATION OF

THE NERVOUS SYSTEM


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SensoryNeurons

SensoryNeurons


Somatic NervousSystem

(voluntary)

Somatic NervousSystem(voluntary)

Autonomic NervousSystem

(involuntary)

Autonomic NervousSystem(involuntary)


THE ORGANIZATION OF

THE NERVOUS SYSTEM


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Sensory NeuronsSensory NeuronsMotor NeuronsMotor Neurons

Somatic Nervous System(voluntary)

Somatic Nervous System(voluntary)

Autonomic NervousSystem (involuntary)

Autonomic NervousSystem (involuntary)


THE ORGANIZATION OF

THE NERVOUS SYSTEM


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SensoryNeurons

SensoryNeurons


Somatic NervousSystem

(voluntary)

Somatic NervousSystem(voluntary)

Autonomic NervousSystem

(involuntary)

Autonomic NervousSystem(involuntary)

Sympathetic

Division

Sympathetic

Division

Parasympathetic

Division

Parasympathetic

Division


THE ORGANIZATION OF THE

NERVOUS SYSTEM


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A General

Sense thepathway of the

nervous system


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THE NERVOUS SYSTEM

Made up of highly specialized cells whose

function is to:

Receive stimuli

Convert the stimuli into electrical

impulses

Transmit the impulses

to

Receptors

Transduction

Effectors

Objective:

(a) Describe the organization of the nervous system


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Sensory input

Brain & spinal cord

Motor input

Peripheral nervous

system (PNS)

Central nervous

system (CNS)

Sensory receptor

Effector

Motor neuron Sensory neuron


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THE NERVOUS SYSTEM

Receives & processes

information

Initiates action

Consist of:Brain

Spinal cord

Central NervousSystem (CNS)Central NervousSystem (CNS)

Objective:(a) Describe the organization of the nervous system


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Outside of the brain and

spinal cord

Transmit signals between

CNS & the rest of the body

Peripheral Nervous

System (PNS)

Peripheral Nervous

System (PNS)

Objective:


THE NERVOUS SYSTEM


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Can be divided into:.

Conducts impulses from receptors to the CNS

Informs the CNS of the state of the body interior

and exterior

.

Conducts impulses from CNS to effectors(muscles/glands)

Sensory Neuron

Motor Neuron

Objective:


Peripheral Nervous System(PNS)

Peripheral Nervous System(PNS)


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Figure 28.1B

Brain

1 Sensoryreceptor 2 Sensory neuron

3

4

Ganglion

Motorneuron Spinal

cord

Interneuron

CNSNerve

PNS

Quadricepsmuscles

Flexormuscles

Objective:



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Divided into:

.Controls voluntary movements

Activates skeletal muscles


Somatic Nervous System

Objective:



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.

Controls involuntary responses

Heart rate, peristalsis, sweating, respiration

Actions are controlled in the medulla and the

hypothalamus in the brain

Influences organs, glands, & smooth muscles

Autonomic Nervous System

Objective:



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Consist of 2 types of neurons:

Preganglionic neuronCell body in CNS

MyelinatedProjects to the autonomic ganglion

Postganglionic neuronCell body in autonomic ganglionUnmyelinatedProjects to the effector

Autonomic Nervous SystemAutonomic Nervous System

Clusters of

neurons

Objective:



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2 divisions:

Sympathetic

Fight or flight

Energetic and

stressful activities

Primes body for

intense skeletal

muscle activity

Autonomic Nervous SystemAutonomic Nervous System

Objective:

(b) Explain the general role of the sympathetic and parasympathetic nervous system.


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Parasympathetic

Rest and digest

Leisure and

maintenance activitiesDigestion, defecation,

and diuresis

Objective:

(b) Explain the general role of the sympathetic and parasympathetic nervous system.


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A t i ti


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Antagonistic

Control

Both act on the sametarget but often giveantagonist effect

Eg: heart rate

Sympathetic stimulation causes

HR to increase

Parasympathetic stimulation

causes HR to decrease
http://d/My%20Documents/Downloads/D:/10.Coordination/Animation/autonomicns.swf


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Figure 28.13

PARASYMPATHETIC DIVISION SYMPATHETIC DIVISION

Brain

Constrictspupil

Stimulatessalivaproduction

Constrictsbronchi

Slowsheart

Stimulatesstomach,pancreas,and intestines

Stimulatesurination

Promoteserection ofgenitals

Spinalcord

Eye

Salivaryglands

Lung

Heart

LiverStomach

Adrenal

gland

Pancreas

Intestines

Bladder

Genitals

Dilatespupil

Inhibitssalivaproduction

Relaxesbronchi

Acceleratesheart

Stimulatesepinephrineand norepi-nephrine release

Stimulatesglucoserelease

Inhibits

stomach,pancreas,and intestines

Inhibitsurination

Promotes ejacu-lation and vaginalcontractions


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SUMMARY:


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PRIOR KNOWLEDGE :

Sensory receptors are in sense organs, such as eyes, ears, mouth,nose, skin and different regions of the brain respond todifferent signals.

Sensory neurons carry messages toward the CNS from sensoryreceptorsall over body.

Sensory receptorsact as energy transducers. A transducer is a

device for converting a non-electrical signal into an electricalone. In this case, the electrical signal produced is the actionpotential of a nerve.

Objective:

(c) Explain the generation of action potential, transmission and characteristic of nerveimpulse along an axon.
http://d/My%20Documents/Downloads/D:/10.Coordination/Animation/actionpotential.swf


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THE GENERATION OF NERVE RESTING

POTENTIAL AND ACTION POTENTIAL

All living cells have an electrical charge

difference across their cell surface membrane

Due to the difference in the concentration of ions

on the outside and inside of a cell

Known as

Membrane Potential

Objective:

(c) Explain the generation of action potential, transmission and characteristic of nerve

impulse along an axon.


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Depends on the ionic gradients exist across the

plasma membrane of the neuron

Develops when the charge is more negative withinthe cell than from the outside

The voltage measured across the plasma membraneis about -70 mV

Resting Potential

The membrane potential

of a neuron that is nottransmitting signals

Objective:

(c) Explain the generation of action potential, transmission and characteristic of nerveim ulse alon an axon.


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Resting potential is caused by the cell

membranes ability to maintain

a +ve charge

on its OUTER surface

a -ve charge

on its INNER(cytoplasmic) surface

Plasmamembrane

Microelectrodeinside cell

Axon

Neuron

Microelectrodeoutside cell

Voltmeter

70 mV

Objective:


Resting Potential


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Inside the neurons,

Higher K+

ions concentrationLower Na+ ions concentration

Outside the neurons,

Higher Na+ ions concentration

Lower K+ ions concentration

Objective:


Resting Potential

The membrane potential

of a neuron that is nottransmitting signals


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Resting potential is generated and

maintained with help from

Active transportSodium-potassium pumpsPump K+ into the cell and Na+ out of the cell

OUTSIDE OF CELL

Na+

Na+

channel

Na+ Na+Na+

Na+K+ K+

Na+

Na+

Na+

Na+

Na+

K+Plasmamembrane

Protein

Na+

K+

K+

K+

K+

K+ K+

K+

K+K+

K+

Na+ - K+pump

Na+

Na+

K+

channel

INSIDE OF CELL

Objective:



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Passive transport (diffusion)

Passive ions channels (Na+ and K+)OUTSIDE OF CELL

Na+

Na+

channel

Na+Na+

Na+

Na+K+ K+

Na+

Na+

Na+

Na+

Na+

K+Plasmamembrane

Protein

Na+

K+

K+

K+

K+

K+ K+

K+

K+K+

K+

Na+ - K+pump

Na+

Na+

K+channel

INSIDE OF CELL

Objective:

http://d/My%20Documents/Downloads/D:/10.Coordination/Animation/nerve05.swf


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Passive K+ ion channel

Most common type of passive ion channel

Neuron membrane is highly permeable to K+ ionsPassively diffuse out according to the

concentration gradient

Potassium ion pumped into (active transport) the

neuron can diffuse out

Objective:



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Passive Na+ ion channel

Allows a slow diffusion of Na+ ions into the membrane

Permeability to Na+ ions is lower than to the K+ ions

Na+ ions pumped out of the neuron cannot easily pass back

into the cell

This results in the resting potential condition or the :

POLARIZATION STAGE

Objective:



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During resting potential:

Sodium-potassium pump

Pump Na+ out and K+ in actively

Passive ions channels

Pumps more K+ out than Na+ passively

Voltage-gated ions channels CLOSED

Objective:



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Figure 28.4

Resting state: voltage gated Na+

and K+ channels closed; resting

potential is maintained.

1

2

3

4

A stimulus opens some Na+

channels; if threshold is reached,

action potential is triggered.

Additional Na+ channels open,

K+ channels are closed; interior of

cell becomes more positive.

5 The K+ channels close

relatively slowly, causing

a brief undershoot.

Na+ channels close and

inactivate. K+ channels

open, and K+ rushes

out; interior of cell more

negative than outside.

Neuron

interior

Actionpotential

Thresholdpotential

Resting potential

1

2

3

4

5

Na+

Na+

Na+

Na+

1 Return to resting state.

1

Neuron

interior

K+

K+NEXT LECTURE

Chapter 20 - Coordination in Mammals (Part 1)

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