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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