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16 Coordination in humans

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Think about it

16.1 What does our nervous system consist of ?

16.2 How does the nervous system function?

16.3What is the structure of the spinal cord and what are its functions?

16.4 What is a reflex action?

16.5What is the structure of the brain and what are its functions?

16.6What are the differences between reflex actions and voluntary actions?

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16.7 What is hormonal coordination?

16.8 How does hormonal control work?

16.9 What are the similarities and differences between hormonal and nervous coordination?

Practical 16.1

STS connection 16.1 STS connection 16.2

Summary concept diagram

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Sanglan (桑蘭 ), a famous Chinese gymnast became paralysed (癱瘓 ) below her thorax after an accident in a practice vault (跳馬 ) .

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What changes occurred in her body after the accident?

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Which part of her body was damaged?

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Do you know the causes of paralysis in other people who have this disability?

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Do you know the causes of paralysis in other people who have this disability?

Our nervous system is important in coordinating the receptors and effectors in our body.

Damage in any part of the nervous system may cause paralysis.

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16.1 What does our nervous system consist of ?

coordination in mammals

endocrine system

nervous system

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Nervous system

16.1 What does our nervous system consist of ?

1 central nervous system (CNS)

2 peripheral nervous system (PNS)

• coordinates the receptors and effectors• consists of two parts:

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General plan of the nervous system

peripheral nervous

system (PNS)

central nervous system (CNS)

cranial nerve

spinal nerve

brain

spinal cord

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Protection of the central nervous system

cranium

central cavity filled with cerebrospinal fluid

(腦脊髓液 )

• provides brain with nutrients and oxygen

• removes wastes from brain cells

• absorbs shock

• maintains shape of brain

3 layers of membranes

Brain

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Protection of the central nervous system Spinal cord

3 layers of membranes

vertebral column

central canal filled with cerebrospinal fluid

spinal cord

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16.2 How does the nervous system function?

Nervous system is made up of neurones (神經元 ).

Neurones …

transmit nerve

impulses

basic units of the

nervous system

nerve cells

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Structure of the neurone

cell body

nucleus

dendron (樹突 )

cytoplasm

axon (軸突 )

myelin sheath (髓鞘 )

nerve fibre

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Structure of the neurone

The make-up of a nerveThe make-up of a nerve

Nerves

nerve fibres of many neurones wrapped in connective tissue

a nerve fibre(axon or dendron)

connective tissue

a bundle of nerve fibres

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Types of neurones

impulses

1 Sensory neurone

receptors CNS cell body

axon

dendron

receptor

in CNS

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Types of neurones

cell body

axon

in CNS

effectorCNSimpulses

effector

2 Motor neurone

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Types of neurones

cell body

axondendron

in CNSmotor neurone

sensory neurone

impulses

3 Interneurone

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Transmission of nerve impulses between neurones

• neurones are separated by synapses (突觸 )

• synapses cause nerve impulses to travel in one direction only

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synapse

axon

dendron

chemicals released from axon ending diffuse across a synapse

Transmission of nerve impulses between neurones

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The role of nervous systemCNS PNS

sensory neurone

interneurone

receptors

effectormotor neurone

interneurone from brain

11 receptor e.g. pain receptor receives stimuli and generates nerve impulses

22 impulses are transmitted to the CNS via sensory neurones

stimuli

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The role of nervous systemCNS PNS

33 information is processed (處理 ) and integrated (融合 ) in CNS which then generates nerve impulses

brain

spinal cord

sensory neurone

interneurone

receptors

effectormotor neurone

interneurone from brain

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The role of nervous systemCNS PNS

44 impulses are transmitted via motor neurones to the effector, e.g. muscle

55 effector brings about a response, e.g. muscle contraction

response

sensory neurone

interneurone

receptors

effectormotor neurone

interneurone from brain

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~ Word corner ~

Cranium, Neurone

Brief RevisionBrief Revision

** Neuro- Nerve

** Crani- Skull

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16.3 What is the structure of the spinal cord and what are its functions?

white matter (outer layer)

grey matter (inner layer)

spinal nerve

dorsal root (sensory neurones)

ventral root (motor neurones)

dorsal root ganglion (cell bodies of sensory neurones)

Structure of the spinal cord

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Functions of the spinal cord• relays nerve impulses between the brain and

other body parts• responsible for many reflex actions

brain

spinal cord

nerve impulses enter and leave the brain through the spinal cord

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16.4 What is a reflex action?

inborn rapid involuntary stereotyped (有固定形式的 )

reflex action (反射動作 )

cranial reflex spinal reflex

is

brought about by

impulses travelling through brain

impulses travelling through spinal cord

brought about by

can be

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Reflex arc

11 receptor

22 sensory neurone

33 intermediate neurone (may be absent)

44 motor neurone

55 effector

• the nervous pathway between a receptor and an effector which brings about a reflex action

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Examples of reflex actions

11 stimulus

22 pain receptors are stimulated

33 impulses sent through sensory neurone

44 interneurone

55 motor neurone

Withdrawal reflex

66 arm muscle (effector) contracts

77 hand withdraws

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11 tendon below the knee cap is tapped

22 stretch receptor is stimulated

33 impulses sent through sensory neurone

44 motor neurone 55 leg muscle (eff

ector) contracts

Knee jerk reflex

66 the leg kicks

Examples of reflex actions

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16.5 What is the structure of the brain and what are its functions?

3 main parts:

cerebrum (大腦 )

cerebellum (小腦 )

medulla (延腦 )

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11 CerebrumCerebrum

• site of intelligence and controls voluntary actions

Outer layer: cerebral cortex grey matter

(cell bodies)

Inner layer: white matter

(axons and dendrons)

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– consists of 2 halves:

• controls left side body movement

– the 2 halves are connected by nerves for communication

2) right cerebral hemisphere

1) left cerebral hemisphere• controls right side body movement

11 CerebrumCerebrum

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3 main areas in the cerebral cortex:3 main areas in the cerebral cortex:

Association areas– link information from different

sensory areas/receptors

Motor areas– send out impulses to effectors

Sensory areas– receive impulses from various

receptors

11 CerebrumCerebrum

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22 CerebellumCerebellum

• outer layer: grey matter inner layer: white matter

• coordinates muscular movements

• maintains balance

cerebellum

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33 MedullaMedulla

• controls many reflex actions and involuntary actions

• outer layer: white matterinner layer: grey matter

medulla

reverse of that in cerebrum and cerebellum

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16.1Examination of a human brain model

Procedure:

1 Examine a human brain model.

2 Identify the structures.

3 Notice the folds on the surface of the brain.

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16.116.1Effects of drug abuse on body organs

Conduct a project on the effects of drug abuse on body organs, particularly the brain.

Go to Activity Book 2, p.143

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Brief RevisionBrief Revision

1 Of the three main parts of the brain, _________ controls voluntary actions, whereas ___________ and _________ controls involuntary actions.

cerebrum

2 The three main areas in the cerebral cortex are the ________ area, the __________ area and the _______ area.

sensoryassociation

cerebellum medulla

motor

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Reflex actions Voluntary actions

involve cerebrum? No Yes

Yes Not necessarilyinvolve

receptor?

16.6 What are the differences between reflex actions and voluntary actions?

No Yesunder

conscious control?

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Reflex actions Voluntary actions

Faster Slower

Stereotyped response

Various responses

speed of response

response to same stimulus

Yes No, they are learnt

inborn?

16.6 What are the differences between reflex actions and voluntary actions?

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16.7 What is hormonal coordination?

Endocrine system

pituitary gland (腦下垂體 )

thyroid gland (甲狀腺 )

pancreas

ovaries (卵巢 )

adrenal glands (腎上腺 )

testes (睾丸 )

woman man

Extension

Main endocrine glandsMain endocrine glands

• responsible for coordination by hormones

• consists of many endocrine glands (內分泌腺 )

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• chemicals secreted by ductless endocrine glands transported in blood

• serve as chemical messengers which act on target organs and regulate body processes

HormonesHormones

Extension

16.7 What is hormonal coordination?

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Transport of hormones:Transport of hormones:

11 secreting cells in endocrine gland secrete hormones

22 hormones diffuse into blood

33 hormones are transported to all parts of the body

44 cells in specific target organs receive hormones and changes occur

Extension

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Examples of endocrine glands

Ovaries and testes

• produce sex hormones (性激素 ) which

1 stimulate ovaries to release eggs (卵子 ) and testes to make sperm (精子 )

2 responsible for the development of secondary sexual characteristics(第二性徵 )

Extension

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Pancreas

• produce insulin (胰島素 ) and glucagon (高血糖素 )

• they work together to regulate the blood glucose level

glucose

insulin

glucagonglycogen

Extension

Examples of endocrine glands

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16.8 How does hormonal control work?

detector

detector

normal level of factors

higher level of factors than normal

lower level of factors than normal

Extension

by a negative feedback mechanism (負反饋機制 )

negative feedback

balancing action to decrease

the level

balancing action to increase

the level

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An everyday example:Extension

RT = room temperatureS = set temperature

The operation of a thermostat (恆溫器 ) of an air-conditioner

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Regulation of blood glucose levelRegulation of blood glucose levelMore insulin is secreted

(1) more glucose is converted to glycogen in liver

(2) more glucose is oxidized to CO2 and H2O in body cells

Less insulin is secreted

(1) more glycogen in liver is converted to glucose

(2) less glucose is oxidized in body cells

Normal blood glucose level

High blood

glucose level

Low blood

glucose level

Blood glucose level falls

Blood glucose level rises

Extension

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Brief RevisionBrief Revision

1 Hormones are secreted by ________________. They act on specific ______________ and regulate body processes.

endocrine glands

2 The blood glucose level is regulated by two hormones: _______ and _________ . They control the interconversion of _________ and _________.

insulin glucagon

target organs

glucose glycogen

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16.9 What are the similarities and differences between hormonal and nervous coordination?

Hormonal coordination

Nervous coordination

Components

Types of message

Transmission route

Extension

Endocrine glands & blood

Neurones, brain & spinal cord

Nerve impulsesHormones

Blood stream Nerve fibres

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Extension

Hormonal coordination

Nervous coordination

Response occurs

Speed of transmission

Duration of response

Body processes involved

In more widespread area

Slower Rapid

Usually long lasting Short term

Reflex actions and voluntary actions

Reproduction, growth, etc. always involuntary

Only in places with nerve supply

16.9 What are the similarities and differences between hormonal and nervous coordination?

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16.216.2Physiological consequences of imbalance of insulin and its remedies

Try to find out the information about diabetes and its remedies, especially through modern advances in science and technology.

Go to Activity Book 2, p.145

Extension

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Summary concept diagramSummary concept diagram

is carried out by

organized into

consists of

responsible for

E

Coordinationin humans

endocrinesystem

neuronescoordinating

different partsof the body

centralnervoussystem

peripheralnervous system

nervoussystem

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Back to summary concept diagram

involved in

including

carried out through

transmits impulses to and from

consists of

centralnervous system

brain spinal cord

involuntaryresponses

reflex actions

reflex arcs

Summary concept diagramSummary concept diagram

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Back to summary concept diagram

voluntaryactions

musclecoordination

balance involuntaryactions

its main parts are

controls

controls

controls

maintains

Summary concept diagramSummary concept diagram

brain

cerebrum cerebellum medulla

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Back to summary concept diagram

peripheralnervous system

cranial nerves spinal nerves

nerves

nerve fibres

axons dendrons

consists of

made up of

each made up of many

classified into

Summary concept diagramSummary concept diagram

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neurones

nerve impulses

classified into

receptors

stimuli fromenvironment

effectors

responses

each consists of

carry messages in the form of

classified into

receive messages from

receive

send messages to

carry out

cell bodynerve fibres

axons dendrons

Summary concept diagramSummary concept diagram

sensoryneurones

interneurones motorneurones

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E

endocrineglands

hormones

targetorgans

negativefeedback

mechanism

endocrinesystem

E

E

E E

consists of

produce chemical messengers called

carried in blood to

their secretion regulated by

Summary concept diagramSummary concept diagram