LECTURER IN CHARGE BAMIDELE OLUBAYODE DEPARTMENT OF PHYSIOLOGY BOWEN UNIVERSITY IWO NIGERIA INTRODUCTION The study of endocrine glands is essential in the field of endocrine Physiology It gives information on how endocrine organs function ID: 932427
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METHOD OF STUDY OF ENDOCRINE GLANDS
LECTURER IN CHARGE
BAMIDELE OLUBAYODE
DEPARTMENT OF PHYSIOLOGY
BOWEN UNIVERSITY, IWO, NIGERIA
Slide2INTRODUCTIONThe study of endocrine glands is essential in the field of endocrine Physiology.
It gives information on how endocrine organs function.
The study of endocrine glands include the following methods:
Anatomical method
Biochemical method
Physiological method
Clinical Method
Slide3Anatomical MethodThis involves the study of the following:
Location of the organ
Its division and parts
Histology
Nerve supply
Blood supply
Slide4Biochemical MethodIt involves the study of the:
chemical constituents of the hormones synthesized by the glands
chemical stucture of the hormone produced by the glands.
half life:It is also called biological halflife. Halflife
of a hormone denotes the elimination of that hormone
from circulation.
ways by which the hormones are formed
Slide5Physiological MethodsThis includes the study of the:
hormones secreted by the glands.
actions of the hormones
The evidence to support the functions of the glands is either by
augumenting
or
decreasing
the various ways the function in question.
Slide6Physiological Method cont'd
Several methods of
augumeting or increasing
the hormone content in the blood include the following:
administration of extract or the hormone of the gland
grafting into the body viable endocrine tissue
stimulation of their secretory nerve
Slide7Physiological Method cont'd
Functional deficiencies (
decrease in hormone secretion
) can be created by:
extirpation (removal) of the gland
injecting substances to cause bland infarct in the glands
ligating the blood vessels supplying the organ in question
Slide8Administration of Extract or the Hormone of the Gland
Experiments with gland extracts are complicated by the fact that in addition to specific hormones, various more or less potent non-specific substances may be present.
When given by mouth these substances ar
e
relatively unimportant but when the extracts are introduced by vein they often play a predominant role in the reactions.
This could produce overactivity of the hormone when this is done in normal gland.
Slide9Grafting into the body viable endocrine tissue
In some instances organ grafting has been used to augment the quantity of circulating hormones.
In the early development of the thyroid treatment of myxedema this procedure was successfully employed.
There are numerous technical difficulties, however, which limit the use of the method in practical experimentation.
The only way in which grafting can be accomplished with anything
like constant success is by the employment of the individual's own tissues (autografting)
.
.
Grafting into the body viable endocrine tissue
The more closely related are the host and the donor of the tissue the more likely is the graft to "take."
Transference from one species to another (heterografting) is prac
t
ically never successful.
Slide11Stimulation of their Secretory Nerve
In some respects stimulation of the secretory fibers to a given gland is the most satisfactory method of augmenting the amount of the corresponding hormone.
The secretion thereby secured is supposedly normal in quality and not greatly outside physiologic limits in quantity.
For this among other reasons, a definite knowledge of the secretory innervation of all the endocrine organs is needed.
Slide12Extirpation (removal) of the Gland
This is the removal of the gland to cause deficiency in the synthesis of the hormone of the gland.
It can be done surgically or by burning off the gland (ablation).
The method is particularly adapted to investigate the problem as to what glands are essential to life.
But even in this case concordant results have not in all
instances been secured.
Slide13Extirpation (removal) of the Gland
For example, Cushing maintains that complete removal of the pituitary gland is inevitably fatal while Aschner, another skilled scientist, is equally sure that animals may survive the operation.
One maintains that death following extirpation of the gland is due to incidental trauma; the other that survival when it occurs is to be ascribed to bits of gland left behind in the operation.
Slide14Injecting substances to cause bland infarct in the glands
Bland infarcts can be
formed
by injecting fine suspensions of inert insoluble material into the arteries leading to different glands.
Tobacco seeds or lycopodium spores are most commonly
used
.
This process involves comparatively little trauma and can be regulated to produce various grades of deficiency.
It is a method, however, somewhat difficult to control. So far it has not led to any striking results
.
Slide15Ligating the Blood Vessels Supplying the Glands
Ligating the blood vessels supplying the glands is one of the methods used clinically and experimentally to decrease their functions.
It is a well known method of treating exophthalmic goitre in patients who are in a serious condition to undergo thyroidectomy.
Experimentally the method in most cases is unreliable. Small vessels may remain untied and become enlarged or cappillaries may grow into the surrounding tissues in the anemic area and vascularised it so the part of the gland can hypertrophy and continue to function.
Slide16Clinical Method
This involves the clinical observation of the patients for hormone disorders.
The disorders may be due to oversecretion or undersecretion of the hormnes.
For example, Addison's discovery that deficiency of the suprarenal glands results in muscular and circulatory weakness remains as probably the most significant information yet offered bearing on the physiology of these glands.
A similar statement may be made in regard to the discovery of the relation of the thyroid glands to myxedema and cretinism.
Slide17References
Sembulinga, K.
Essentials of Medical Physiology. Sixth Edition.
Endocrinology. Methods of investigating endocrine functions.
Slide18Thank you for your attention
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