The nervous system Life Science 2010 鄭先祐 (Ayo) 製作.

The nervous system

Life Science 2010

鄭鄭鄭 (Ayo) 製作

The nervous system 2

• Fig. 22.1 animal nervous systems

• (a) Hydra, with no coordinating center

• (b) planarian, with a brain.

• (c) Earthworm, well-defined brain.

• (d) Frog, well-developed brain protected by bone.

• (e) human.


The nervous system• Central nervous system ( 中樞神經系統 )

– Brain + spinal cord

• Peripheral nervous system ( 周圍神經系統 )– Somatic nervous system

• cranial nerves

• spinal nerves (dorsal + ventral root)

– Autonomic nervous system ( 自主神經系統 )• Sympathetic nervous system ( 交感神經系統 )

• parasympathetic nervous system ( 副交感神經系統 )

Table 22.1 parts of the human nervous system


Fig. 22.2 a simple reflex arc is shown

in the knee-jerk response.


• Notice the diminutive size of the cerebrum relative to the olfatory bulb in fish.

大腦小腦

延腦嗅囊

Fig. 22.3 (a) fish (b) snake


Fig. 22.3 (a) cat (b) human

(c)

The nervous system 7Fig. 22.4 Birds are so stupid because they can fly.


• Fig. 22.5 Under the wrinkled exterior of the human brain resides an incredibly complex array of neurons.


Fig. 22.6 The human brain in surface view, showing the two halves,, or cerebral hemispheres.

大腦皮層

視丘

橋腦小腦

The nervous system 10Fig. 22.6 (b) Major lobes of human brain.

額葉

頂葉

枕葉

顳葉

小腦延腦


Table 22.2 Function of human brain

• Medulla oblongata ：呼吸、消化、心跳、 ...• cerebellum ：控制平衡和協調。• Pons 連接大腦和小腦。• Thalamus ： The great relay station• Reticular system ：過濾感覺神經訊息• Hypothalamus ：調解心跳、血壓、体溫、

和腦下垂體，控制饑餓、口渴和性的動機。


Fig. 22.7 The reticular system of the human brain. The impulse originating at the lower right passes

through the reticular system, with its untold

millions of neurons.

The smaller arrows indicate the entire cerebrum has been alerted, but a specific part (the lighted area) is the target of most of the impulses.

The nervous system 13Fig. 22.8 Sensory and motor cortex.

感應區動作區

思考區


Essay 22.1 Penfield's mapping

• Wilder Penfield, of the Montreal Neurological Institute, was one of the group of researchers who fascinated scientific world by stimulating the human brain with electrodes.

• Most of work was done on epileptic ( 癲癇 ) patients.


Epileptic patients

• the attacks are caused by uncontrolled neural discharges from the injured area sporadically surging through the brain.

• Penfield's surgery was an attempt to identify and remove the damaged area without damaging other areas of the brain.

• The patients were conscious throughout the operation (the brain can not feel pain) and could respond to questions when various parts of their brain were stimulated.


Essay 22.1 Penfield's mapping

• Penfield was able, in effect, to "map" the brain, to determine which parts are associated with specific functions.

• Penfield found that the human brain may "remember" virtually everything it has ever experienced, and that these memories can be elicited in very specific terms.

• We all have what are called "photographic memories" to an extent.


• Penfield has described the storage of such memories as being similar to recording by a tape recorder.

• The recorder is able to run only forward, and it has only one speed.

• Electrode stimulation cannot elicit events in any sequence other than the one in which they happened, and, when elicited, these remembered events are re-experienced at the same rate they occurred.


Two Brains, Two minds?

• Fig. 22.9 The right and left sides of the brain control, in a general way, different abilities.

• 左腦：言語、理性、作文

• 右腦：音樂、三度空間感、直覺、想像


Fig. 22.10 The corpus callosum is a broad tract of nerve fiber that connects the two

hemispheres of the brain.


Fig. 22.11 Splitting the two visual fields of the brain.

• 有 corpus callosum 可以整合左右影像。

• 若是切開，則無法整合。


Fig. 22.12 The autonomic nervous system.

交感神經副交感神經


Fig. 22.13 The sensory System detects the

presence of a bear and relays that information to the cerebrum, where the

bear is recognized as such. The hypothalamus and sympathetic nervous system are then activated,

which stimulates the adrenal medulla to

secrete norepinephrine.


Fig. 22.13


Autonomic Learning

• Researchers of Rockefeller University were able to teach rats to increase or decrease heart rate, blood pressure, intestinal contractions, blood vessel diameter, and even rate of urine formation.

• The ones in the desired direction were rewarded by electrical stimulation of the "pleasure center" of the brain; variations in the other direction were punished by a slight but unpleasant shock.


• Some of the amazing feats accomplished by some practitioners of yoga, such as when they drastically lower their metabolic rate, may be due to autonomic learning (Fig. 22.14)

• Fig. 22.14 Yogis may work their wonders by using autonomic learning to alter the condition of their tissues.


Biofeedback • People are provided with information that

allows them to monitor their autonomic processes and control them.

• For example, when given information on their brainwaves, they may learn to consciously generated those waves that indicate restfulness and peace (Fig. 22.15)

Fig. 22.15 腦波

(a) wakeful

(b) at rest


Fig. 22.15 Biofeedback techniques allow the subject to monitor his or her brainwaves and thus to increase the

likelihood of generating waves of a specific type, such as those associated with relaxation.

Here, an entire football team reduces stress before a game with techniques learned through biofeedback training.


Mindbenders

• Drugs are psychoactive agents: that is, they can alter mood, memory, attention, control, judgement, time-and space sense, emotion, and sensation.

• Most cause effects that can be placed along a continuum between stimulation and depression (Fig. 22.16).


Fig. 22.16 ( 上半部 stimulation)A continuum of drug action. The effects are shown at left, the various agents at right. The

neutral area is drug free.


Fig. 22.16 ( 下半部 depression)A continuum of drug action. The effects are shown at left, the various agents at right. The

neutral area is drug free.


Essay 22.2 pills and personalities

• Do you ever feel dumb? If so, maybe there's a pill in your future.

• Are you ever impulsive( 衝動 )? 購買慾？

• Are you shy? Forgetful?

• 這些都有各別的藥丸。


藥丸的功效• A shy child may have an easily stimulated

amygadala.

• Shy children my also produce too much of the excitatory neurotransmitter norepinephrine. A drug that blocks the receptors for epinephrine at the synapse could help.

• Too little serotonin leading to fewer social invitations.


• Other drugs can reduce obsessive behavior ( 強迫性行為 ) (such as constant and needless cleaning), impulsiveness (that can lead to shoplifting, or kleptomania 竊盜狂 ), and anxiety ( 焦慮 ).

• There are drugs that can help concentration, increase memory, and stimulate other traits that can increase IQ scores on tests.

• Will a changed person still be the same person? If someone is to be changed, who decides? Is it good or bad?


The growth of psychopharmacology

• Tree advances have propelled the growth of psychopharmacology.

• (1) there is good evidence that emotion springs from the activity of neurotransmitters operating in certain parts of the brain

• (2) we have abundant information regarding which part of the brain controls what emotions.

• (3) we're learning which transmitters operated in each of those areas.


Tabacco• Tabacco is the dried leaf of the plant Nicotiana

tabacum.

• Over 6800 different chemicals are found in tobacco smoke, many of them carcinogens.

• The major psychoactive product nicotine is carcinogenic.

• In large doses, nicotine may also cause cramps( 抽筋 ), vomiting( 嘔吐 ), diarrhea( 腹瀉 ), dizziness( 頭昏 ), confusion( 困惑 ), and tremors( 發抖 ).


Smoking

• The development of the smoking habit is curious. 另外就是香煙強力廣告的誘惑。

• Smoking may cause physiological and psychological dependence on the products in the smoke.


Table 22.3 some mindbending drugs

• Tobacco ( 煙草 ) ： stimulant 生理和心理依賴• Caffeine ( 咖啡 ) ： stimulant 有點心理依賴• THC(marijuana/hashish, 大麻 ) ：少量鎮定，

多量有幻覺可能會產生心理依賴• Alcohol ： depressant 生理和心理依賴• Opiates( 鴉片 ) ： depressant 強烈的生理依賴• Cocaine( 古柯鹼 ) ： stimulant 生理和心理依賴


Table 22.3 some mindbending drugs

• Amphetamines ( 安非他命 ) ： stimulant 生理和心理依賴

• Barbiturates( 巴必妥 ) ： depressant 生理和心理依賴

• Phencyclidine ： relaxation, euphoria, 幻覺• Methaqualone ： depressant 生理依賴• Psychedelics ：幻覺


Fig. 22.18 Marijuana plants were once a common weed. The species, however, has undergone tremendous artificial

selection to produce plants high in THC ( 大麻 ).


• Fig. 22.19 An early governmental warning of the hazards of marijuana use. Such exaggeration have led to a general skepticism regarding such warnings.


• Fig. 22.20 Photo of Coca-Cola ad touting that it contains cocaine.


Essay 22.3 The hangover ( 宿醉 ) • A hangover is a

seemingly interminable but temporary chemical imbalance in the body, caused by alcohol acting as an anesthetic on the central nervous system.


• Fig. 22.21 Admitted to a hospital as a result of an overdose of barbiturates.

This person is in a stupor( 昏迷 ) at this point but has been tied down because he can be expected to be violent should be ever awaken.


The hangover ( 宿醉 )

• A dilation of blood vessels in the brain, the movement of water, potassium, and other ions from the cell outward to the intercellular spaces, depletion of magnesium form the kidneys, and inflammation of the stomach lining.

• The results are headache, insatiable thirst, upset stomach, fatigue, grouchiness( 嘮叨 ), and perhaps remorse( 懊悔 ).

• The morning-after drink provides superficial relief while slowing down recovery.


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Ayo NUTN website: http://myweb.nutn.edu.tw/~hycheng/

The nervous system Life Science 2010 鄭先祐 (Ayo) 製作.

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Transcript of The nervous system Life Science 2010 鄭先祐 (Ayo) 製作.