Download Endocrine filled

ENDOCRINE SYSTEM
Endocrine system consists of organs that produce and secrete hormones
"endocrine" = internal secretion
into capillaries
Hormones carried by the blood to another organ; exert effects
Hormones manipulate specific enzymes of metabolic processes
directly or indirectly activating the genes
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ENDOCRINE SYSTEM
Pituitary gland
a. General aspects
(1) Three different regions of
separate origin; almost totally
unrelated
Pituitary
Gland
anterior lobe
Paraventricular
nucleus
Supraoptic
nucleus
OT & ADH production
OT & ADH production
Hypothalamus
anterior pituitary,
adenohypophysis
intermediate lobe
Infundibulum
pars intermedia
Optic
chiasma
Intermediate lobe
Pars intermedia
posterior lobe
posterior pituitary,
neurohypophysis
Pars
tuberalis
Posterior lobe
Neurohypophysis
posterior pituitary
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Anterior lobe
Adenohypophysis
anterior pituitary
ENDOCRINE SYSTEM
Pituitary gland is located on the underside of the diencephalon portion of the brain,
just posterior to the optic chiasma
where the two optic tracts cross
Spherical ; human adults, about 7 mm in diameter.
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ENDOCRINE SYSTEM
Neurohypophysis --composed of neural tissue of the CNS
white matter
Contains glial cells and capillaries.
Glial cells same as earlier; called pituicytes.
No neuron bodies
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ENDOCRINE SYSTEM Skip slide
Nerve fibers, axons of neurons in the
diencephalon
paraventricular nucleus
supraoptic nucleus.
Pass down the stalk of the neurohypophysis
infundibulum; ; end in the
neurohypophysis
Axons terminate on the capillaries in that
tissue
Nuclei generate impulses; sent to the
neurohypophysis
Axon terminals release oxytocin or antidiuretic hormone (aka, ADH or
vasopressin) into blood.
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ENDOCRINE SYSTEM
Adenohypophysis
(1) Composed of two different forms
of glandular epithelial tissue.
(2) Anterior lobe
Pars distalis and pars tuberalis .
Packed endocrine glandular
epithelial cells, sinusoids and
capillaries.
Three types of endocrine cells
Pituitary
Gland
Paraventricular
nucleus
Supraoptic
nucleus
OT & ADH production
OT & ADH production
Hypothalamus
Infundibulum
Pars
tuberalis
Optic
chiasma
Intermediate lobe
Pars intermedia
Posterior lobe
Neurohypophysis
posterior pituitary
Anterior lobe
Adenohypophysis
anterior pituitary
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ENDOCRINE SYSTEM
Types of endocrine cells present
1. Chromophil(ic) cells: cytoplasm stain
with H&E
Acidophilic Cells; a above
(pink to red; Cells; large and
spherical.
secrete;
Somatotropin
(growth hormone)
Prolactin
(lactogenic hormone.)
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ENDOCRINE SYSTEM
Basophilic Cells; b above
light dull blue-gray;
small ;cuboidal.
secrete;
Thyrotropin (thyroidstimulating hormone)
Lutenizing (interstitialcell-stimulating)
hormone,
FSH (follicle stimulating
hormone) and ACTH
(adrenocorticotropic
hormone)
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ENDOCRINE SYSTEM
Chromophobe cells:
cytoplasm does not stain
with H&E. c above
Nucleus surrounded by
space.
Probably are immature
cells.
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ENDOCRINE SYSTEM
Intermediate lobe (pars intermedia)
Basophilic glandular epithelial tissue in clumps (follicles) and sacs (vesicles)
between pars distalis and posterior pituitary gland
secretes melanocyte-stimulating hormone, aka, MSH.
Not significant in humans
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ENDOCRINE SYSTEM
Thyroid gland
Composed (about 95%) of thyroid follicles
between thyroid follicles is interstitial connective tissue
containing small blood vessels and parafollicular cells
adipose tissue is present in and around CT
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ENDOCRINE SYSTEM
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ENDOCRINE SYSTEM
Thyroid follicle
Thyroid follicle is a hollow sac;
simple endocrine glandular epithelium
Inactive follicles: cells are flat; between cuboidal and squamous cells; aka, low-cuboidal
Moderately active follicles: cuboidal cells:
Very active follicles: low-columnar cells:
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ENDOCRINE SYSTEM
Follicle Lumen contains a colloid
Colloidal dispersion of a large protein molecule
Protein eosinophilic
Protein binds the hormone for storage
Follicle produces thyroxin (tetra-iodothyronine);
Active form of the molecule, within the cells of the body where it acts, is triiodothyronine.
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ENDOCRINE SYSTEM
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Adrenal gland
General aspects
“next to the kidney”; superior
kidney.
Cortex and medulla
medulla is a single,
interior, mass of tissue
cortex is a relatively
thick complex layer
surrounding the
medulla
outermost ; thin capsule
of dense C.T.
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ENDOCRINE SYSTEM
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ENDOCRINE SYSTEM
Adrenal medulla
Clumps or cords; large lightly basophilic cells; scattered small blood
vessels.
Hormones epinephrine (adrenaline) and norepinephrine
(noradrenaline) by direct stimulation of the sympathetic part of the
autonomic nervous system.
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ENDOCRINE SYSTEM
Adrenal cortex --divided into 3 layers; hormones produced are all steroids
Zona reticularis
(a) innermost
next to medulla.
(b) cells are in a network of branching cords, with sinusoids in-between.
(c) Cells are spherical to cuboidal in shape, and their cytoplasm stains well with eosin
cords are about 1 cell thick.
(d) Androgens or androgen precursors, in both males and females.
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ENDOCRINE SYSTEM
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Zona fasciculata (f)
(a) middle; thickest.
(b) Cells in parallel sheets, perpendicular to surface
capillaries or sinusoids lie between the sheets, hard to see.
(c) Cells are spherical to cuboidal ; stains very lightly with H&E
tiny spherical holes; represent storage vacuoles.
(d) Glucocorticoids
i.Cortisol
ii. Cortisone; one most commonly administered therapeutically.
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Zona glomerulosa (g)
(a) outermost ; thinnest
(b) Layer is composed of spherical clumps of endocrine cells;
capillaries or sinusoids between
layer is one to two clumps (glomeruli) thick.
Glomeruli are not hollow.
(c) Cuboidal to low columnar in shape
cytoplasmic staining is intermediate between other layers.
(d) Mineralocorticoids
Aldosterone; regulates Na+ and water balance.
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ENDOCRINE SYSTEM
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Cortex
Medulla
R
F
G
Capsule
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