nervous systen and hormone

8/9/2019 nervous systen and hormone

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VOW PAGE

I admit that this coursework is my own work that I have done it myself except for the

article and summary that I have explained the sources.

Signature : (_______________________)

Name : SITI QURRATUL AINI ULFA BINTI RODIN JAYA

I/C NO : 910606-03-6028

Date : ___ ________________ 2010.


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BIOLOGY 2

THE NERVOUS SYSTEM

AND

THE HORMONE AND COORDINATION

SCIENCE DEPARTMENT

IPG KAMPUS SULTAN MIZAN, KOTA PUTRA, BESUT, TERENGGANU


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APPRECIATION

Assalamualaikum.

Firstly I am very grateful because finally I did finished my coursework task on the

right time given. First of all, I would like to convey my appreciation to my parents. This is

because they had given me a lot of supports in doing this coursework perfectly.

I would like to thank my dedicated lecturer and also my coordinator from the

bottom of my heart. He have helped me and my classmates on how to understand this

coursework and make it easier and simple. Without his help, I does not sure whether I

can finished this coursework on time or not.

I also wanted to convey my appreciation to all of my friends for giving me

lots of moral supports and pulling me up each time I fall. They have helps me in doing

this coursework and they also did gave comments on my coursework such as their

opinion about the arrangement of the tasks, views about the task and so on.

Thank you.


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CONTENTS

VOW PAGE I

HEADING ENCLOSURE II

CONTENTS III

INTRODUCTION 1

1.0 GRAPHIC NOTES

1.1 Nervous System 2 - 6

1.2 Hormone and coordination 7 - 10

2.0 INVESTIGATION 11 - 22

REFLECTION 23

BIBLIOGRAPHY 24

COLLABORATION FORM 25


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INTRODUCTION

A nervous system involves the detection of stimuli (sensory inputs) integration

and response (motor output). The response may be to both the internal and external

environments. This enables the organisms to survive, to obtain foods, and to reproduce

to maintain their species. Maintenance of a constant internal environment provides

optimum conditions for enzymatic reactions and normal cell activities.

All animals contain chemical components produced by exocrine orendocrine

glands. Exocrine glands release their chemicals into ducts. The endocrine glands

(Figure 22.1) release their secretions, the hormones,directlyinto the blood-stream.

These hormones are then carried to other parts of the body (targetorgans), where in

extremely minute quantities, they elicit cellular responses. E.H.Starling (1902)

suggested the name hormone (Greek meaning "to stimulate" or "to excite") for these

chemical messengers or transmitters.

Hormones are specifically-acting organic compounds with varying chemical

compositions, usually steroids, proteins, peptides or amino acids. Based on their

general roles, hormones are metabolic (stimulate or retard metabolic activities),

trophic(regulate rate and secretion of other endocrine glands) and morphogenetic

(affect rate and development of various parts).

Hormones are an additionalmeansofcoordination andcommunication.

Together with the nervous system, the endocrine system forms a combinedneuro-

endocrinesystem. The hormone pathway is by the bloodstream, while nervous

pathway is by theneuron-reflex arc


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1.1.1 Organisation of the nervous system

The nervous system of a mammal comprises of :

Cental Nervous System (CNS)

Consisting of the brain and the spinal cord

Peripheral Nervous System (PNS)

Consisting of the cranial nerves from the brain, the spinal nerves from the spinalcord and the sense organs

Nervous System

Central NervousSystem (CNS)

Brain

Spinal Cord

Perpheral NervousSystem (PNS)

Voluntary (somatic)nervous system

Cranialnerves

Spinal nerves

Autonomic NervousSystem

Sympatheticnervous system

Spinal nerves

Parasympatheticnervous system

Cranialnerves

Spinal nerves


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1.1.2 Cells of the nervous system

A neuron (nerve cell) is the basic functional unit of the nervous system. Neurons are

cells specialized to generate and transmit nerve impulses (action potentials).

There are three basic types of neurons :

A nerve consists of many neurons bound together by connective tissues. It varies in

length and diameter.

Transmit nerve impulses from the receptors to the central nervoussystem.

Sensory neurons (Afferent neurons)

They are the major components of the integration centres in the centralnervous system.

E.g : Interneurons connect sensory neurons to the motor neurones.

Interneurons (Association neurons)

Transmit impulses from the central nervous system to the effectors (motororgans).

E.g : Muscles or glands that carry out the response.

Most motor neurons are stimulated by impulses conducted by

interneurons.However, there sre some that are stimulated by sensory neurons.

Motor neurons (Efferent neurons)

Sensory nerves Only sensory neurons

Motor nerves Only motor neurons

Mixed nervesBoth sensory and motor

neurons


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Structure of a neuron

A cell body. cytoplasm contains many mitochondria, endoplasmic reticulum,

golgi apparatus, and ribosomes.

Each motor neuron possesses

Consists of endoplasmic reticulum and ribosomesthat functioninprotein synthesis.

Nissl granules

Number of processes from the cell body.

Dendrons

The fine terminal branches.

Conduct nerve impulse towards the body.

Dendrites

Conducts impulse away from the cell body.

Contains axoplasm surrounded by the axon membrane

(axomembrane).

Axon

The terminal branches of the axon ends in knoblike structures.

Contains many mitochondria, endoplasmic reticulum, and synapticvesicles filled with neurotransmitters.

Synaptic knobs

The small uncovered parts of the myelinated axon between theschwann cells.

Nodes of Ranvier

Forms the axons that are covered with a fatty myelin sheath.

Located at regular intervals with their cell membranes wrappedaround the axon.

Schwann cells


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In the myelinated fibre, the myelin shealth has three function :

Receptors

In animals, stimuli are detected by receptors or sensory cells. A receptor may be a

specialized cell which makes synaptic contact with a sensory neuron or it may be part of

the structure of a sensory neuron.

Receptors are stimulated by specific stimuli. There are five main types :

Function of myelinsheath

Guidesregeneration of

PNS axons

Acts as an electricalinsulator and prevents

movement of ions.

Speeds up thetransmission of nerve

impulse along theaxon.

Receptors

Chemoreceptors By chemicals

MechanoreceptorsPressure, touch, sound

waves and tension(strecth)

ThermoreceptorsChanges in environmental

temperature

Photoreceptors by light

ElectroreceptorsElectrical fields and are

found mainly in fish


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1.2 HORMONE AND COORDINATION IN HUMAN

Consist of chemical substances that can alter the cell metabolism or thebehaviour of an individual

Chemical signals

Receptors for chemical messengers are proteins with specific bindingsites located either in the cytoplasm, nucleoplasm, or more commonly,in the cell surface membrane of the target cell.

Receptors

Cells that can recognise and respond to specific chemicals signals

Target cells

3 types of signalling

Local signalling

Paracrine signalling

Synaptic signalling

Long distancesignalling

(hormonal) signalling betweenof the tissue or organs

Signalling betweenindividuals of a

species

E.g : pheromones are emitted

to act as chemical signals thatoften influence the

reproductive behviour ofsome mammals and insects


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Paracrine signaling :

- A secretory cell secretes local regulator molecules.

- E.g : Acetylcholine diffuse through extracellular fluid to act on nearby target

cells.

Synaptic signaling :

- A neuron release neutrotransmitter molecules.

- E.g : Diffuse through the synaptic cleft to act on adjacent neurons.

Long distance signaling :

- Specialised endocrine cells secrete hormones into body fluids, mainly into the

blood.


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1.2.1 The Human Endocrine System

The main coordinating systems in animals are the nervous systemand endocrine

system. The two system coordinate to maintain homeostatic control of the bodys

internal environment. The nervous system provides for rapid responses while the

endocrine system regulates more long-term changes.

The endocrine glands are ductless glands. This gland secrete chemicals called

hormones. Most of the hormones are secreted directly into the surrounding capillaries.

They are carried by the bloodstream to the target cells or organs. (Neurohormones are

produced by the specialized nerve cells called neurosecretory cells).

Nervous System Endocrine SystemSignal Nerve Impulses Hormones which act as

chemical messengerTransporting medium

for signalNerve impulse transmitted alongneurons and across synaptic cleft vianeutransmitters

Blood

Duration A shorter time is required for a nerveimpulse to generated and betransmitted. Effects are usually short-lived.

It takes a longer time fora hormone to beproduced and to reachthe target cell.

Localisation of

responses

Responses are localized to the

effector.E.g : A muscle or a specific gland.

Responses are

widespread.


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Hormones are chemical messengers required in minute quantities.

Roles of hormones include regulating cell metabolism, homeostasis, growth,

reproduction or behavior of an individual.

Hormones act by :

Activating genes in target cells, regulatingproduction of specific proteins or enzymes.

Activating enzyme cascadereactions.

Secretion of hormone regulated intwo ways :

by negative feedback and/or antagonistic hormonal actions


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2.0 Investigation about the hormone and coordination in human from the website.

a) Method :

a. Surfing the internet.

b. Find the information about hormone and coordination in human.

c. Analyze what is the importance of hormone coordination and its effect in

human.


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b) Observation :

a. The importance of hormone coordination.

A substance, usually a peptide or steroid, produced by one tissue and

conveyed by the bloodstream to another to effect physiological activity,

such as growth or metabolism.

Important in control,coordination and regulation of the body's systems.

The major endocrine glands are the pituitary, the thyroid, the four

parathyroids, the pancreas, the two adrenals, and the paired testes or

ovaries (See endocrine). Hormones are also produced by organs or

tissues whose function is not primarily an endocrine one: the digestive

tract, the heart, and the kidneys all produce hormones. Even nerve cells

produce them. For example, the hormones controlling secretion from the

anterior lobe of the pituitary gland are synthesized in the hypothalamus,

but they are released into the local blood supply to the anterior pituitary,

rather than entering the general circulation. These cells are said to have a

neuroendocrine function. Furthermore, it is now recognized that hormones

need not even be released into blood vessels. The hormonal products of

some nerve cells stimulate adjacent neurones and thus act as

neuromodulators, while in the digestive tract hormones act on surrounding

cells and are said to have a paracrine function (para: Greek for beside).

Finally, some hormones, such as growth factors, can act on the originating

cell itself; in this case they are described as exhibiting autocrine control.

The classical definition has therefore been extended to include chemical

messengers which are secreted by certain cells, and which reach and act

upon cells which are receptive to them, whether local or distant.


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b. Effects of hormone coordination in human.

1. Change enzymatic activity / alter cellular metabolism.

2. Change membrane permeability (alters nervous response and

behavior).

3. Cause other glands to release their own hormone.

4. Effects of disorder regulation of hormone in human body :

- Pituitary gland is pea-sized structure located at the base of the brain.

- In humans, it consists of two lobes: the Anterior Lobe and the Posterior Lobe

- Thyroid Stimulating Hormone (TSH). TSH is also known as thyrotropin The

secretion of TSH is stimulated by the arrival of thyrotropin releasing hormone

(TRH) from the hypothalamus inhibited by the arrival of somatostatin from the

hypothalamus. As its name suggests, TSH stimulates the thyroid gland to secrete

its hormone thyroxine (T4). Some people develop antibodies against their own

TSH receptors. When these bind the receptors, they "fool" the cell into making

more T4 causing hyperthyroidism. The condition is called thyrotoxicosis or

Graves' disease.

- Hormone deficiencies. A deficiency of TSH causes hypothyroidism: inadequate

levels of T4 (and thus of T3 ). Recombinant human TSH (Thyrogen) is now

available to treat patients with TSH deficiency. Some people inherit mutant TSH

receptors. This, too, results in hypothyroidism. A deficiency of TSH, or mutant

TSH receptors, have also been implicated as a cause of osteoporosis. Mice,

whose TSH receptors have been knocked out, develop increased numbers of

bone-reabsorbing osteoclasts.

- Follicle-Stimulating Hormone (FSH)FSH. Synthesis and release of FSH is

triggered by the arrival from the hypothalamus of gonadotropin-releasing

hormone (GnRH). The effect of FSH depends on one's sex FSH in females. In

sexually-mature females, FSH (assisted by LH) acts on the follicle to stimulate it

to release estrogens. FSH produced by recombinant DNA technology (Gonal-f)

is available to promote ovulation in women planning to undergo in vitro

fertilization (IVF) and other forms of assisted reproductive technology. FSH in


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malesIn sexually-mature males, FSH acts on spermatogonia stimulating (with the

aid of testosterone) the production of sperm.

- Luteinizing Hormone (LH)LH is synthesized within the same pituitary cells as

FSH and under the same stimulus (GnRH). The effects of LH also depend on

sex. LH in female sIn sexually-mature females, a surge of LH triggers the

completion of meiosis I of the egg and its release (ovulation) in the middle of the

cycle; stimulates the now-empty follicle to develop into the corpus luteum, which

secretes progesterone during the latter half of the menstrual cycle.Women with a

severe LH deficiency can now be treated with human LH (Luveris) produced by

recombinant DNA technology. LH in malesLH acts on the interstitial cells (also

known as Leydig cells) of the testes stimulating them to synthesize and secrete

the male sex hormone, testosterone. LH in males is also known as interstitial cell

stimulating hormone (ICSH).

- Prolactin (PRL)Prolactin is a protein of 198 amino acids. During pregnancy it

helps in the preparation of the breasts for future milk production.

After birth, prolactin promotes the synthesis of milk. Prolactin secretion is

stimulated by TRH repressed by estrogens and dopamine. In pregnant mice,

prolactin stimulates the growth of new neurons in the olfactory center of the

brain.

- Growth Hormone (GH)Human growth hormone (HGH; also called somatotropin)

is a protein of 191 amino acids. The GH-secreting cells are stimulated to

synthesize and release GH by the intermittent arrival of growth hormone

releasing hormone (GHRH) from the hypothalamus. GH promotes body growth

by binding to receptors on the surface of liver cells. This stimulates them to

release insulin-like growth factor-1 (IGF-1; also known as somatomedin) IGF-1

acts directly on the ends of the long bones promoting their growth things that can

go wrong. In childhood, hyposecretion of GH produces the stunted but

normally well-proportioned growth of a midget. Growth retardation can also

result from an inability to respond to GH. This can be caused by inheriting two

mutant genes encoding the receptors for GHRH or GH or homozygosity for a

disabling mutation in STAT5b, which is part of the "downstream" signalin process


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after GH binds its receptor. Hypersecretion leads to gigantism In adults, a

hypersecretion of GH or GHRH leads to acromegaly. Hormone-replacement

therapyGH from domestic mammals like cows and pigs does not work in

humans. So for many years, the only source of GH for therapy was that extracted

from the glands of human cadavers. But this supply was shut off when several

patients died from a rare neurological disease attributed to contaminated glands.

Now, thanks to recombinant DNA technology, recombinant human GH (rHGH) is

available. While a great benefit to patients suffering from GH deficiency, there

has also been pressure to use it to stimulate growth in youngsters who have no

deficiency but whose parents want them to grow up tall. ACTH the

adrenocorticotropic hormone.

- ACTH is a peptide of 39 amino acids. It is cut from a larger precursor

proopiomelanocortin (POMC). ACTH acts on the cells of the adrenal cortex,

stimulating them to produce glucocorticoids, like cortisol mineralocorticoids, like

aldosterone androgens (male sex hormones, like testosterone in the fetus, ACTH

stimulates the adrenal cortex to synthesize a precursor of estrogen called

dehydroepiandrosterone sulfate (DHEA-S) which helps prepare the mother for

giving birth. Production of ACTH depends on the intermittent arrival of

corticotropin-releasing hormone (CRH) from the hypothalamus.

Hypersecretion of ACTH is a frequent cause of Cushing's disease.

- Alpha Melanocyte-Stimulating Hormone (-MSH)Alpha MSH is also a cleavage

product of proopiomelanocortin (POMC). In fact, -MSH is identical to the first 13

amino acids at the amino terminal of ACTH.

- The Posterior Lobe. The posterior lobe of the pituitary releases two hormones,

both synthesized in the hypothalamus, into the circulation.

- Antidiuretic Hormone (ADH). It is also known as arginine vasopressin. ADH acts

on the collecting ducts of the kidney to facilitate the reabsorption of water into the

blood. This it acts to reduce the volume of urine formed (giving it its name of

antidiuretic hormone). A deficiency of ADH or inheritance of mutant genes for its

receptor(called V2)leads to excessive loss of urine, a condition known as

diabetes insipidus. The most severely-afflicted patients may urinate as much as


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30 liters (almost 8 gallons!) of urine each day. The disease is accompanied by

terrible thirst, and patients must continually drink water to avoid dangerous

dehydration.

- Another type of receptor for arginine vasopressin (designated V1a) is found in

the brain, e.g., in voles and mice (rodents) and in primates like monkeys and

humans. Male prairie voles (Microtus pinetorum) and marmoset monkeys have

high levels of the V1a receptor in their brains, tend to be monogamous, and

help with care of their young. Male meadow voles (Microtus montanus) and

rhesus monkeys have lower levels of the V1a receptor in their brains, are

promiscuous, and give little or no help with the care of their young.

- OxytocinOxytocin. It acts on certain smooth muscles: stimulating contractions of

the uterus at the time ofbirth; stimulating release of milk when the baby begins to

suckle.Oxytocin is often given to prospective mothers to hasten birth. Oxytocin

also acts on the nucleus accumbens and amygdala in the brain where it

enhances: bonding between males and females after they have mated;

bonding between a mother and her newborn; and, in humans, increases the level

of one's trust in other people.


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c) Graphics :

a. Endocrine glands : ductless, produce hormones that are release into

blood.


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b. Exocrine glands : have ducts, discharge hormones / secretions directly

onto tissues or surfaces.


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c. Mechanisms of action

a) Receptors

1. membrane-bound receptors

- hormone (= 1st messenger) binds with receptor embedded in cell membrane

- binding stimulates enzyme, adenylate cyclase

- adenylate cyclase catalyzes conversion of ATP to cyclic AMP (cAMP = 2nd

messenger)

- cAMP activates protein kinase A; influences enzymatic pathways

- alters cellular metabolism and cause target cell response

- can produce many cAMPs for each molecule of hormone = amplification

- effects of hormone on cell are indirect.


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2. Nuclear receptors

For steroids (lipid soluble) :

- hormone crosses cell membrane.

- binds with receptor in cytoplasm or nucleus (regardless, site of activity =

nucleus).

- hormone + receptor = gene regulatory protein.

- binds with specific genes; alters transcription and number of mRNA copies

produced.

- mRNAs move into cytoplasm enzymes; alters cellular metabolism and causes

target cell response one gene regulatory protein can result in many mRNA

copies = amplification.

- effects of hormone on cell are direct.


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For thyroid hormones and insect ecdysone:

- hormone binds with transmembrane protein transport molecule.

- ATP used to move hormone across membrane into cell.

- hormone binds with receptor in cytoplasm or nucleus (regardless, site of activity

= nucleus).

- hormone + receptor = gene regulatory protein.

- binds with specific genes; alters transcription and number of mRNA copies

produced.

- mRNAs move into cytoplasm enzymes; alters cellular metabolism and causes

target cell response.

- one gene regulatory protein can result in many mRNA copies = amplification.

- effects of hormone on cell are direct.


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b) Control of hormone secretion : negative feedback loops.

- hormone causes a response in target tissue that inhibits production of the

hormone.


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REFLECTION

Assalamualaikum.

Finally, I did manage to finish this biology coursework within the time given.

Behind the process of finishing this coursework, I have gone through many difficulties

instead of finishing this coursework. I am having problems with the time management,

the sources for finding the information of the coursework, and the arrangement of the

coursework.

Time management is really testing me to be a good time manager from now until

the future. With lots of coursework, I need to find sometimes for finishing this

coursework. I tried to manage my time instead of busy finishing all the coursework

given to me. I make the schedule and follow the schedule according which coursework

should be done first and which coursework should be submit first. This is because I do

not want to keep rushing on something because sometimes when we keep rushing, our

work will end in trouble.

Besides, I really find it difficult to find the information to put in this coursework. I

went to library and borrowed some books, searched on health books at home, and

surfing the internet for various information to be taken. But, it seems like the information

is still not much. But, I tried to collect all the information and make it into group to see

which parts is still not enough for doing the coursework.

Lastly, the arrangement of the coursework sometimes is confusing me. All

contents looks the same and my head stuck in the middle of the arrangement. But,I tried

to calm myself and do it slowly. Moreover, I ask my friends help on their opinions about

the arrangement for the coursework. Finally, I did manage to finish it.

Thank you.


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BIBLIOGRAPHY

B.S.Beckett, (1986) Biology A Modern Introduction GSCE Edition, Great Britain, Oxfor

University

Gairdner B.Moment, Ph.d, Helen M. Ph.d, (1977) Mainstream of Biology, USA, The

William & Wilking Company

Joan E.Rahn, (1974) Biology The science Of Life, United States Of America, Macmillan

Publishing

Lee ching (2009), Pre-U Text Stpm Biology Volume 1, Shah Alam, Selangor Darul

Ehsan, Longman

Thomas A.Steyaert, (1971) Life Are Patterns Of Order, USA, Mc Graw-Hill

www.bisnet.or.id.GASEOUSEXCHANGE , accessed on 10 March 2010

www.rsc.org/education/teachers/learnnet/cfb/CIRCULATORY.htm, accessed on 13

March 2010

www.tutorvista.com, accessed on 14 March 2010

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nervous systen and hormone