Endocrinology is the study of …

The term Hormone (hormao^G= to excite) was first used by ‘William M.Bayliss’ and his brother-in-law ‘Ernest H.Starling’, both of London University college, in 1904, who showed that a chemical stimulate the action of a pancreatic secretion. These substances were then called “Chemical Messengers”.

Definition:

According to Went & Thimann (1937),

“A substance which produced in any one part of an organism, is transferred to another part and there influences a specific physiological process”.

Properties:

A hormone is a Chemical messengers. It has the following properties:

• ·It travels in the blood.
• It has its effect at a site different from the site where it is made, called the “Target”, hence the term “Messenger”.
• It fits precisely into receptor molecules in the target like a key in a lock-it is therefore Specific for a particular target.
• It is a small soluble organic molecule.
• It is effective in low concentrations.
• These have low molecular weight & diffuse readily.

Location of principal endocrine glands:

a) Two in the head region --> The pineal & the Pitutary

b) Three in the neck region --> The Thymus, the Thyroid & Parathyroid

c) Four in the abdominal region –> The Pancreas, The Gastrointesinal mucosa,

The adrenals & The Gonads

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ENDOCRINOLOGY


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“About Cell Concept” for CSIR NET exam

(a) Marcello Malpighi (1628-1694), an Italian microscopist, studied the structure of plants. He believed that the plants are composed of separate structural units which he called “utricles”.

(b) Robert Hooke (1635-1703), examined thin slices of cork (dead outer bark of an oak) under his microscope. He saw hundreds of very small hexagonal ‘boxes’ or ‘chambers’ which are together appeared like a ‘honeycomb’. The term ‘cell’ was coined by Robert Hooke to denote these chambers. His observations, alongwith the figures, were published in 1665 in Micrographia.

(c) Anton von Leeuwenhoek, 1674, using good quality simple lenses (magnifying upto 200 times) observed unicellular organisms and called them ‘wild animalcules’. In this way, he was the first to observe “living and moving individual” cells as compared to the “fixed” cells seen by earlier workers.

(d) H.J.Dutrochet (1824), a French scientist, boiled some tissues and separated the cells from one another. He expressed the idea of individual cells i.e., cells were not just spaces between a network of fibres, but that these were separate and separable units.

(Thanks for IFAS, Jodhpur)

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Introduction to cell for CSIR NET

Evolution: Fact and Theory (For CSIR NET Exam)

Evolution theory explains how organisms have changed over time.

Scientific understanding requires both facts and theories that can explain those facts in a coherent manner.

Evolution, in this context, is both a fact and a theory. It is an incontrovertible fact that organisms have changed, or evolved, during the history of life on Earth. And biologists have identified and investigated mechanisms that can explain the major patterns of change.

There are four major patterns of change.

Patterns in Nature

The field of evolutionary biology seeks to provide explanations for four conspicuous patterns that are manifest

in nature. The first three concern living species, whereas the fourth relates to fossils.

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Evolution facts CSIR

GATE-XL Life science previous papers 2008

Graduated Aptitude Test in Engineering Examinations

GATE Previous Papers - 2008

XL-Life Sciences

Chemistry (Compulsory) -- 2008
Biochemistry -------------- 2008
Biotechnology ------------- 2008
Botany -------------------- 2008
Microbiology -------------- 2008
Zoology ------------------- 2008

Download the GATE XL previous papers by clicking the above links. these are PDF documents. plz use Adobe reader software.

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