Selasa, 05 April 2011

Science Brain and Behavior contiuned 11

CH03.qxd 1/28/05 9:54 AM Page 106

In genetic engineering, genes can be introduced into an embryo or removed from
it. For example, the introduction of a new gene can allow goats to produce medicines
in their milk, and those medicines can be extracted from the milk to treat human diseases
(Niemann et al., 2003). It is also possible to produce chimeric animals, which have
genes from two different species. A cell from one species is introduced into the early
embryonic stage of a different species. The resulting animal has cells with genes from
both parent species and behaviors that are a product of those gene combinations.
The chimeric animal displays an interesting mix of the behaviors of the parent
species. For example, chickens that have received Japanese quail cells in early embryogenesis
display some aspects of quail crowing behavior rather than chicken crowing behavior,
thus providing evidence for the genetic basis of some bird vocalization (Balaban
et al., 1988). The chimeric preparation provides an investigative tool for studying the
neural basis of crowing because quail neurons can be distinguished from chicken neurons
when examined under a microscope.
One application of genetic engineering is in the study and treatment of human genetic
disorders. For instance, researchers have introduced into a line of mice the human
gene that causes Huntington’s chorea (Lione et al., 1999). The mice express the abnormal
huntingtin allele and display symptoms similar to the disorder in humans. This
mouse line is being used to study potential therapies for this disorder in humans.
As described at the beginning of this section (see “Knocking Out Genes” on page
100), knockout technology can be used to inactivate a gene so that a line of mice fails to
express it (Eells, 2003). That line of mice can then be used to study possible therapies
for human disorders caused by the loss of a single protein due to a mutant gene. Remarkably
interesting knockout animals can be bred. Examples are a knockout mouse
that grows up with a superior memory or with no memory and a mouse that is allowed
to grow up quite normally and the gene is then knocked out in adulthood.
It is potentially possible to knock out genes that are related to certain kinds of
memory, such as emotional memory, social memory, or spatial memory. Such technology
provides a useful way of investigating the neural basis of memory. So genetic
research is directed not only toward finding cures for genetic abnormalities in brain
and behavior, but also toward studying normal brain function.
In Review .
Researchers in genomics study how genes produce proteins, whereas those studying proteomics
seek to understand what individual proteins do. Each of our 46 chromosomes contains
thousands of genes, and each gene contains the code for one protein. The genes that
we receive from our mothers and fathers may include slightly different versions (alleles) of
particular genes, which will be expressed in slightly different proteins. Abnormalities in a
gene, caused by mutations, can result in an abnormally formed protein that, in turn, results
in the abnormal function of cells. Recessive or dominant alleles can result in neurological
disorders such as Tay-Sachs disease and Huntington’s chorea, respectively. Genetic engineering
is a new science in which the genome of an animal is altered. The genetic composition
of a cloned animal is identical with that of a parent or sibling; transgenic animals
contain new or altered genes; and knockouts have genomes from which a gene has been
deleted. The study of alterations in the nervous systems or in the behavior of animals produced
by these manipulations can be a source of insight into how genes produce proteins
and how proteins contribute to the structure and function of the nervous system.
Figure 3-28
A Clone and Her Offspring Dolly
(right) was cloned in 1996, when a team
of researchers in Scotland implanted a
nucleus from a mammary-gland cell of
an adult sheep into another ewe’s
unfertilized egg from which the nucleus
had been removed. The resulting embryo
was implanted into a third sheep’s
uterus. Dolly subsequently mated and
bore a lamb (left).
AP Photo/John Chadwick
To learn more about creating knockout
mice, visit the Brain and Behavior Web site
and go to the Web links for Chapter 3.
CH03.qxd 1/28/05 9:54 AM Page 107

What kinds of cells are found in the nervous system? The nervous system is composed
of two kinds of cells: neurons, which transmit information, and glia, cells that support
brain function. Sensory neurons send information from the body’s sensory receptors to
the brain,motor neurons send commands enabling muscles to move, and interneurons
link sensory and motor activities in the CNS. Like neurons, glial cells can be grouped by
structure and function. Ependymal cells produce cerebrospinal fluid; astrocytes structurally
support neurons, help to form the blood–brain barrier, and seal off damaged
brain tissue;microglia aid in the repair of brain cells; and oligodendroglia and Schwann
cells myelinate axons in the central and peripheral nervous systems, respectively.
What is the basic external structure of a neuron? A neuron is composed of three basic
parts: a cell body, or soma; branching extensions called dendrites designed to receive
information; and a single axon that passes information along to other cells.A dendrite’s
surface area is greatly increased by numerous dendritic spines; an axon may have
branches called axon collaterals, which are further divided into teleodendria, each ending
at a terminal button, or end foot. A synapse is the “almost connection” between a
terminal button and the membrane of another cell.
How is a cell internally structured? A surrounding cell membrane protects the cell and
regulates what enters and leaves it.Within the cell are a number of compartments, also
enclosed in membranes. These compartments include the nucleus (which contains the
cell’s chromosomes and genes), the endoplasmic reticulum (where proteins are manufactured),
the mitochondria (where energy is gathered and stored), the Golgi bodies
(where protein molecules are packaged for transport), and lysosomes (which break
down wastes). A cell also contains a system of tubules that aid its movements, provide
structural support, and act as highways for transporting substances.
Why are proteins important to cells? To a large extent, the work of cells is carried out
by proteins. The nucleus contains chromosomes, which are long chains of genes, each
encoding a specific protein needed by the cell. Proteins perform diverse tasks by virtue
of their diverse shapes. Some act as enzymes to facilitate chemical reactions; others
serve as membrane channels, gates, and pumps; and still others are exported for use in
other parts of the body.
How do genes work? A gene is a segment of a DNA molecule and is made up of a sequence
of nucleotide bases. Through a process called transcription, a copy of a gene is
produced in a strand of mRNA. The mRNA then travels to the endoplasmic reticulum,
where a ribosome moves along the mRNA molecule, and is translated into a sequence
of amino acids. The resulting chain of amino acids is a polypeptide. Polypeptides fold
and combine to form protein molecules with distinctive shapes that are used for specific
purposes in the body.
What do we inherit genetically from our parents? From each parent, we inherit one of
each of the chromosomes in our 23 chromosome pairs. Because chromosomes are
“matched” pairs, a cell contains two alleles of every gene. Sometimes the two alleles of
a pair are homozygous (the same), and sometimes they are heterozygous (different).
An allele may be dominant and expressed as a trait; recessive and not expressed; or
codominant, in which case both it and the other allele in the pair are expressed in the
individual organism’s phenotype. One allele of each gene is designated the wild type,
or most common one in a population, whereas the other alleles of that gene are called
mutations.A person might inherit any of these alleles from a parent, depending on that
parent’s genotype.
108 ! CHAPTER 3
neuroscience interact ive
There are many resources available for
expanding your learning online:
Try the Chapter 3 quizzes and
flashcards to test your mastery of the
chapter material. You’ll also be able to
link to other sites that will reinforce
what you’ve learned.
Learn more about knockout technology
and gene function.
Review genetics at this Web site from
the Cold Spring Harbor Laboratory.
On your Foundations CD-ROM, you’ll
be able to begin learning about the cells
of the nervous system in the module on
Neural Communication. This module
includes animations and detailed
drawings of the neuron. In addition,
the Research Methods module includes
a video clip of neurons and glia, as well
as a detailed overview of various
CH03.qxd 1/28/05 9:54 AM Page 108

1. Describe five kinds of neurons and five kinds of glia and their functions.
2. Describe the functions of the different parts of a cell.
3. Why can so many nervous system diseases be due to faulty genes?
People often compare the “machine of the day” to the nervous system. Why can we
never understand our nervous system by comparing it to a computer and how it works?
Alberts, B., Bray, D., Lewis, J., Raff, M., Roberts, K., & Watson, J. D. (2002).Molecular
biology of the cell (4th ed.). New York: Garland. This standard text provides a
comprehensive description of the cells and cell function in living organisms.
Levitan, I. B., & Kaczmarek, L. K. (2002). The neuron: Cell and molecular biology (3rd ed).
Oxford: Oxford University Press. An extremely readable text describing the function of
the neuron. The coverage is comprehensive, and the text is enjoyable to read,
accompanied by numerous illustrations that assist in explanation.
What is the relation among genes, cells, and behavior? Comprehending the links
among genes, cells, and behavior is the ultimate goal of research, but as yet these links
are only poorly understood. The structure and function of a cell are properties of all
its many genes and proteins, just as behavior is a property of the actions of billions of
nerve cells. It will take years to learn how such a complex system works. In the meantime,
the study of genetic abnormalities is a potential source of insight.
What causes genetic abnormalities? Genes can potentially undergo many mutations,
in which their codes are altered by one or more changes in the nucleotide sequence.
Most mutations are harmful and may produce abnormalities in nervous system structure
and behavioral function. Genetic research seeks to prevent the expression of genetic
and chromosomal abnormalities and to find cures for those that are expressed.
allele, p. 101
astrocyte, p. 84
axon, p. 76
axon collateral, p. 79
axon hillock, p. 79
bipolar neuron, p. 79
cell body (soma), p. 76
channel, p. 96
dendrite, p. 76
dendritic spine, p. 79
Down’s syndrome, p. 104
end foot (terminal button),
p. 79
ependymal cell, p. 82
gate, p. 96
glial cell, p. 82
heterozygous, p. 101
homozygous, p. 101
Huntington’s chorea, p. 104
hydrocephalus, p. 84
interneuron, p. 81
microglial cell, p. 84
multiple sclerosis (MS),
p. 85
mutation, p. 101
myelin, p. 85
oligodendroglial cell, p. 85
paralysis, p. 85
pump, p. 96
Purkinje cell, p. 81
pyramidal cell, p. 81
Schwann cell, p. 85
soma (cell body), p. 76
somatosensory neuron,
p. 79
synapse, p. 79
Tay-Sachs disease, p. 103
tumor, p. 82
wild type, p. 101
CH03.qxd 1/28/05 9:54 AM Page 109

110 !
C H A P T E R4
How Do Neurons Transmit
Focus on Disorders: Epilepsy
Electricity and Neurons
Early Clues to Electrical Activity in the Nervous
Modern Tools for Measuring a Neuron’s Electrical
How the Movement of Ions Creates Electrical Charges
Electrical Activity of a Membrane
Resting Potential
Graded Potentials
The Action Potential
Focus on New Research: Opening the
Voltage-Sensitive Gates
The Nerve Impulse
Saltatory Conduction and Myelin Sheaths
How Neurons Integrate Information
Excitatory and Inhibitory Postsynaptic Potentials
Focus on Disorders: Myasthenia Gravis
Summation of Inputs
The Axon Hillock
Into the Nervous System and Back Out
How Sensory Stimuli Produce Action Potentials
How Nerve Impulses Produce Movement
Focus on Disorders: Lou Gehrig’s Disease
Studying the Brain’s Electrical
Single-Cell Recordings
EEG Recordings
Event-Related Potentials
Left: Dr. David Scott/Phototake. Middle: Mason Morfit/
FPG International/PictureQuest. Right: CNRI/Phototake.

Tidak ada komentar:

Kesehatan bagun Pagi dan Meditasi

Dimana saat bangun pagi hari dan melihat sekeliling hidup dimana setelah kedua bola mata ini mulai berkerja untuk melihat sesuatu apa saja,sehingga pikiran mulai bekerja dengan apa yang dilihat,Meditasi dapat dilakukan disaat aktifitas mata dan pikiran mulai bekerja untuk menetukan perbuatan apa yang mau dilakukan oleh pandangan dari kedua bola mata ini,jadi setiap gerakan dari lihatan mata pikiran bekerja untuk menetukan apa langka yang harus di laksanakan baik yah dan baik tidak,manusia itu sendiri yang menentukan apa yang perlu dikalukan,sampai dengan melihat dikala bangun dari tempat tidur dan berdiri untuk langka selajutnya apa,kemudian berjalan kemana yang di inginkan oleh penglihatan bola mata dan diperintakan oleh pikiran yah atau tidak,akan tetapi setiap kehidupan manusia baik wanita dan laki-laki itu sama cuman perbedaan jenis kelamin,coba pola melihat dan pikiran banyak yang menyerupai tidak bedannya dimana manusia itu hidup dalam lingkungan ,akan tetapi setiap mengerakan badan jasmani ini dapat dilihatberupa melihat dan bergerak keselulu penjuruh,Meditasi sangat mendukung dimana prilaku yang kurang sadar apabila manusia disaat mulai bergerak dari aktifitasnya,jadi disaat aktifitas dari setiap gerakan yang tidak sadar itu dapat menjadi sadar apabila di bantu dengan meditasi dan kosentrasi yang tidak sadar menjadi sadar yang muncul dari pikiran manusia itu,kadang-kadang dapat dilihat kesadaran seseorang dapat berkurang akibat banyaknya aktifitas,sibuk,strees,marah,benci,irihati,kawatir,banyak berpikir,menghayal,beragan-agan,ambisi,menagis,tertawa,derita,dan bahagia dan lain-lainnya,

Kehidupan yang sehat merupakan yang terbaik apabila pikiran yang sehat dan badan jasmani juga sehat,baik kesadaran yang baik dengan tidak terjadi kecelakaan baik yang kecil dan yang besar dan mencelakai diri sendiri itu merupakan kesehatan dari pikiran dan badan jasmani yang dalan keadaan sadar dan itu merupakan sehat dan kehidupan,Meditasi dapat menyehatkan tubuh jasmani manusia yang kurang sadar dalam kehidupannya,yang terpenting adalah konsentrasi apa saja yang dilakukan dalam kegiatan sehari-hari itu lebih baik. oleh : Tjung teck S.Ag
Ada kesalahan di dalam gadget ini

National Geographic Photos

Ada kesalahan di dalam gadget ini

Yahoo! News: Technology


kurang kesehatan dari jasmani dan rohani antara Meditasi

Banyak orang dari berbagai ragam manusia yang ada sangat saat ini kurang sehat dari semua apa yang diraih dari setiap kehidupan dimana berada,seperti dengan halnya ketidak stabilnya ekonomi masyarakat yang berkembang dengan masyarakat maju berkembang pesat,kadang-kadang dapat dilihat dari perselisihan yang terjadi akibat dari kurang sehatnya pikiran manusia yang ingin lebih baik dari sesamanya diaman berada.

Aternatip kesehatan dampak kesehatan biology dan Meditasi

kesehatan fisik (jasmani) dan rohani dari dampat yang ditimbulkan oleh system kerja dari badan fisik atau jasmani itu sanggak mendukung dimana proses demi proses setiap metabolisme dari tubuh fisik manusia itu berasal dari dirinya sendiri yang untuk menentukan dimana kemanpuan seseorang yang dinyatakan sehat, dimana harus mengetahui dari awal dan akhir terutama untuk melatih Meditasi,dimana orang yang mengalami sakit yang kornis sekalipun dapat melakuakan Meditasi itu,baik secara fisik dan rohania dapat melakukan meditasi secara konsentrasi dengan object masing-masing dari semua unsur kehidupan metabolosme dari setiap kehidupan dialam semesta ini.tentunya tidak luput dari pengaru lingkungan dimana manusia itu berada dengan sesamanya, baik kehidupan yang baik dan kehidupan yang buruk itu semua kembali dari awal dimana manusia itu tumbuh dan berkembang dimana berasal,tidak luput dari kesehatan dan terserang penyakit tidak memandang manusia apa saja itu bisa terjadi dimana saja dan kapan saja selagi manusia itu tumbuh dan berkembang biak dengan satu dengan yang lainnya.

Dampak keshatan biology dan Meditasi sangat berhubungan erat dimana dampak yang ditimbulkan berupa kesehatan dari fisik atau jasmani yang mengerakan semua kehidupan dari system tubuh monotorik dari kehidupan manusia itu,terutama kepada dirinya sendiri sebagai manusia dimana manusia itu mempunyai rohani yang disebut dengan batin dan pikiran yang timbul dan lenyap dari proses alamia dari otak besar dan otak kecil yang melalui memory-memory sensorik dari setaip saraf-saraf yang berkerja sama dengan otot-otot dan urat-urat baik besar,menegah dan kecil dari semua system anatomi tubuh metabolosme manusia itu,sehingga lebih banyak dilihat dari semua gerakan berasal dari hujut perintahan-peritahan dari pikiran itu,yang baik gerakan secara menual dan rifek dapat digerakan dengan menual dan otomatis dari setiap kehidupan tubuh manusia itu,kemudian tidak luput oleh setiap makan yang di konsumsi setiap hari oleh manusia yang dapat dilihat dari makan yang mengandung gizi atau tidak tergantung sisi kehidupan manusia itu berasal dari mana dan lingkungan dimana manusia itu hidup.

sprituality antara biology dan hubungan Meditasi kesadaran

sprituality antara biology dan hubungan Meditasi kesadaran
kunjungan rapat SAGIN

kesehatan biology dan Meditasi

Daftar Blog Saya


Mengenai Saya

Foto saya
Saya seorang Buddhist yang sedang menjalani kehidupan Spiritual sesuai dengan ajaran Buddha. Akan tetapi saya berusaha dengan tekun untuk manfaat bagi umat Buddha supaya terus melestarikan Buddha, Dharmma, dan Sangha dimana saja, perbuatan karma baik dapat berbuah dalam ketenangan dan kebahagiaan diri sendiri dan semua makhluk hidup di dunia ini. Agama Buddha adalah merupakan Ajaran yang mengajarkan kita untuk melaksanakan Danasikha, sila, samadhi dan Panna. Demikianlah suatu hujud prilaku dan moral etika dapat berjalan dengan baik, didalam kehidupan dimana berada untuk hidup tenang dan Bahagia sewaktu hidup, sebagai umat manusia dimana berada, jalankan kehidupan ini sebaik-baiknya supaya kehidupan dapat mengikuti aturan-aturan kehidupan yang berkeTuhanan Yang Maha Esa.
Ada kesalahan di dalam gadget ini

NASA Image of the Day

The Daily Puppy

Endangered Animal of the Day

Ada kesalahan di dalam gadget ini

Search Ebay

Ada kesalahan di dalam gadget ini

Google Finance Market Summary