SUMMARY(anat19)
Endocrine organs
1. Pituitary gland
2. Saccus vasculosus
3. Epiphysis
4. Urophysis spinalis
5. Thyroid gland
6. Ultimobranchial gland
7. Thymus
8. Pseudobranch
9. Adrenal system
10. Corpuscles of Stannius
11. Island-cells of the pancreas
12. Digestive tract as endocrine organ
Pituitary (gland) Òàù»á÷ô÷(12)
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[Embryological aspects]
a. The ventral wall of the 3rd ventricle (ie., diencephalon)
b. The roof of the oral cavity
1) Location
--- Suspended from hypothalamus beneath the diencephalon of the brain
--- Attached to the brain by means of its stalk
2) Composition
(1) Adenohypophysis
(2) Neurohypophysis
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3) Functions
--- Secretion of Prolactin\ ACTH\ TSH\ GTH
Saccus vasculosus(11) úìηҥ
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1) Shape
--- An unpaired, vesicular organ with high degree of vascularization
2) Location
--- An evagination of the wall of the infundibulum closely posterior to the pituitary
--- A thin walled structure/ Outer surface covered by the meninges
3) Functions
--- Still subject to much discussion
Epiphysis(3)
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--- Projected dorsally from the epithalamus of diencephalon
1) Shape
--- Tube-shaped in teleostei and elasmobranchii
--- A distal thickening/ A somewhat-broadening base
2) Location of end vesicle
--- Projected dorsally from the epithalamus of diencephalon
3) Composition
a. A connective tissue sheath covering the entire organ
b. Internal ependymal lining
c. Lumen communicating with the 3rd ventricle
4) Functions
--- Generally sensitive to light
--- Certain similarity in histology to the retina of the eye
--- Mainly influencing the cycle of daily activity
Urophysis spinalis
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--- Recognized only in teleosts and elasmobranchs
--- A ventral thickening of the spinal cord
--- Three structural types of urophysis
--- Functions
--- An organ deposits which releases materials produced in the neurosecretory
cells located in the spinal cord
--- Considerable variation of opinions as to the function
a. Osmoregulatory or not ?
b. Contraction of smooth muscle
c. Possible relationship with the active and abrupt motion of caudal portion
Thyroid gland
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--- The floor of the gill-basket
--- More or less large accumulation of vesicles or follicles
Thyroid gland in teleosts
--- Generally diffusely distributed in the region of the above mentioned blood vessels, the ossa
basibranchialia and the m. sternohyoideus
--- Blood supply
--- Ventral branches or elongation of the efferent gill arteries
--- No parathyroid gland in fishes
Ultimobranchial bodies
--- Vesicular protrusions from the last gill slit
--- postbranchial or suprabranchial bodies
--- Originating from the region of the gill slits
--- Both sides or ventral to the esophagus near the sinus venosus in Teleostei
--- Confined to the space between the gill basket, the esophagus and the pericardium
--- Discrete organ in all calsses of vertebrates except for agnatha(Missing)
--- Fused to the thyroid in mammals
--- Functions
--- Calcitonin
Thymus
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--- On the sides of the gill basket in all fishes except adult agnatha
Pseudobranch
--- An endocrine function
--- On the inner side of the gill cover or in about the same region on the base of the skull
--- Often deeply embedded in the surrounding tissue
--- Functions
--- The exchange of CO2
The adrenal system Üùãìͧ
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--- Not a unitary adrenal gland
1. Interrenal organs
--- Developing out of the peritoneum
--- Considerable variation in shape and size
--- Functions of interrenal organ
--- Hypertrophy during sexually-active phase
2. Suprarenal organ
--- Homologous to the adrenal medulla
--- A completely different origin from the interrenal organ
--- Chromaffine- or phaeochrome system
--- Adrenaline and noradrenaline
--- Chromaffin cells located outside of the organ
The corpuscles of Stannius
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--- Only found in holostei\ teleostei
--- Usually located somewhat dorsally in the middle line of the caudal portion of the kidney,
where the right and left kidneys come into contact with each other
--- Functions
--- Alteration in the level of Na+, K+ and Ca2+ in the blood
--- Strong vascularization
--- No formation of corticosteroids
The island-cells of the pancreas
--- Generally not a compact organ
--- Usually diffu
--- Endocrine portion of pancreas in teleostei
--- a. Region of the exocrine pancreas
b. Mesentery and spleen
c. Hepatic portal veins
d.
Gall bladder
The digestive tract as endocrine organ
1) Stomach
--- Gastrin\ Serotonin
2) Small intestine
--- Hormones from the small intestine
--- Influencing the secretion of bile and pancreatic juice and the activity of the stomach
The entire gastro-intestinal endocrine system
--- a. Probably primarily important for the organ in which it is locatd
b. Sensations as those of hunger\ satiation
The urogenital tract as an endocrine organ
--- Testis\ Ovaries
--- Hormones
--- Controlled by hormone from the pituitary gland
--- Gonadotrophic hormones(GTH)
--- The specific sex hormones
--- Only synthesized in the presence of the spermatogonia or the oogonia
a. Interstitial tissue or organ
--- The Leydig cells
--- Also described in teleostei
--- The location of Leydig cells in teleostei
--- Not always found in the same position as are in other vertebrates
b. Sertoli cells
--- Formation of a kind of supporting tissue between the spermatogonia and the spermatocytes
--- As nurse cells
c. The epithelium of the ductus efferentes(Xenentodon cancila, Beloniformes)
d. The theca
interna of the primary follicles in the female lampreys
The kidneys as an endocrine organ
--- Glandular epitheloid or juxtaglomerular cells
--- Walls of the afferent arterioles (middle tunic)
--- Developing out of smooth muscle cells
--- Equivalent to the juxtaglomerular cells of mammals
--- No production of hormones
--- Production of renin, a proteolytic enzyme
---Angiotensin
--- blood pressure
Urine
formation
