Endocrine histology lab
Dr.Deema Hamarsheh
Pituitary gland ( Hypophysis) Adrenal gland Thyroid gland Parathyroid gland Pineal gland Islets of langerhans
The hypophysis consists of two glands :
Adenohypophysis
Neurohypophysis
Pars distalis ( anterior pituitary)
Pars tuberalis
Pars intermedia
Pars nervosa
Infundibulum ( neural stalk )
Stem
Median eminence
( oral ectoderm )
( nerve tissue )
We have three cell types based on their differential staining with H&E :
1) Basophils 2) Acidophils 3) Chromophobes (unstained or
weakly stained cells )
The neurohypophysis consists of : 1) unmyelinated nerve fibres derived
from neurosecretory cells of the supraoptic and paraventricular hypothalamic nuclei
2) Pituicytes (oval or round nuclei ) - 25% of the volume - specific type of glial cells
Neurosecretory material consists of two hormones : 1) Oxytocin from mostly from paravetricular nuclei
2) antidiuretic hormone (ADH or vasopressin ) mostly from
supraoptic nuclei
Adrenal Gland
The adrenal (or suprarenal) glands consist of : an outer cortex (the main part of the adrenal
glands)
inner medulla
cortex
he cortex is divided into three concentric zones which, from the surface inwards, are termed : The zona glomerulosa (accounting for about 15% of the cortical
thickness) ----mineralocorticoids are produced in this zone The zona fasciculata (about 75%) ------glucocorticoids The zona reticularis(about 10%) ------ sex hormones
Medulla
Cells are arranged in strands or small clusters. The cytoplasm of the cells is weakly basophilic. They are called chromaffin cells because the
granules of these cells can be stained with potassium bichromate.
Secretes catecholamine derived from neural crest cells.
Thyroid Gland
The thyroid gland consists almost entirely of rounded cysts, follicles, which are separated by scant interfollicular connective tissue.
The colloid is the secretory product of the follicular cell , Its main component, thyroglobulin, consists of triiodothyronine and tetraiodothyronine (or thyroxine).
C cells (or parafollicular cells) surrounds the entire follicle.
Parathyroid gland
These glands are small A considerable number of fat cells infiltrate the gland
(beginning around puberty) and may account for about half the weight of the parathyroid glands in adults.
Two cell types can be distinguished in the parathyroid glands: Chief cells are the most numerous type. They are rather
small, a round, light and centrally placed nucleus and a very weakly acidophilic cytoplasm. They synthesise parathyroid hormone (PTH or parathormone) which is of pivotal importance for normal calcium concentrations in the fluids and tissues of the body.
Oxyphilic cells are less frequent (entirely lacking in small
children ,Their cytoplasm is strongly acidophilic, the nucleus is small and uniformly intense basophilic. They contain large amounts of mitochondria.
Pineal Gland
The pineal body is surrounded by pia mater
n the pineal we find two cell types: pinealocytes and astrocytes
pineal gland also contains brain sand (corpora arenacea). For calcium and magnesium
Small dark nuclei belong to the astrocytes found in the pineal gland.
Pinealocytes have larger, lighter and round nuclei, which are surrounded by a broad rim of light cytoplasm.
The most prominent secretory product of the pineal body is melatonin
Most nuclei present are the
nuclei of pinealocytes
Islands of Langerhans, usually containing several hundred endocrine cells, are scattered throughout the exocrine tissue of the pancreas.
Islands of Langerhans
75% beta-cells which secrete insulin. Insulin stimulates the synthesis of glycogen, protein and fatty acids
20% alpha-cells which secrete glucagon. The effects of glucagon are generally opposite to those of insulin. (they are typically smaller than those of delta-cells
5% delta-cells which secrete somatostatin, a locally acting hormone which inhibits other endocrine cells
PP celi : secretes pancreatic polypeptide