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37 Cards in this Set
- Front
- Back
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Endocrine Cell
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4 main hormone types
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1. peptides & proteins (insulin, FSH, GH)
synthesized by rER, stored in cytoplasmic granules and exocytosed when required 2. Steroids (oestrogens, glucocorticoids) derived from cholesterol synthesised in mitochondria & rER, not stored but released via diffusion 3.Tyrosine/amine-derived (dopamine, serotonin, epinephrine) synthesized from tyrosine stored in granules & released via exocytosis (thyroid hormones) stored extracellularly in colloid-filled cavities 4. Fatty acid derivatives (prostoglandins, leukotrienes) synthesized by rER stored in granules & released via exocytosis |
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HYPOTHALAMO-HYPOPHYSEAL PORTAL CIRCULATION
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Hypothalamus – neurosecretory neurons synthesize hormones which are transported to pituitary via vessels and axons
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Anterior Pituitary Gland
- 3 parts |
derived from developing oral cavity
contains epithelial cells - sinusoidal cappilaries in pars intermedia |
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POSTERIOR PITUITARY GLAND
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neurohypothesus
1. stalk; infundibulum 2. pars.. |
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Histology: LOW power
Pituitary |
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BLOOD SUPPLY TO PITUITARY GLAND
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pars distalis
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•Cells arranged in clumps or cords
•Separated by fenestrated sinusoidal capillaries •Classified by their histochemical staining quality •Accurate differentiation requires immunocytochemical staining |
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[pars distalis
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Pars distalis
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Pars Distalis = secretory cells and sinusoidal capillaries
- how to Dd b/w the secretory cells? |
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electron microscope image of secretory cells in adenohypophysis
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electron microscope image of sinusoidal capillary in the adenohypophysis
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ADENOHYPOPHYSIS
pars distalis - % cell types |
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ADENOHYPOPHYSIS
pars intermedia |
Colloid-filled FOLLICLES
FOLLICLE CELLS (epithelial) - secrete MSH and endorphin |
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ADENOHYPOPHYSIS pars tuberalis
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•very VASCULAR region = VEINS
•CORDS of EPITHELIAL CELLS •small FOLLICLES lined with ACTH, FSH and LH cells |
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NEUROHYPOPHYSIS
extension of the nervous system |
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NEUROHYPOPHYSIS
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1.Non-myelinated axons
2.Neurosecretory products (oxytocin, ADH) 3.Fenestrated sinusoidal capillaries 4.Glial cells (Pituicytes) |
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Neurohypophysis hormones
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NEUROHYPOPHYSIS pars nervosa
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The axons are unique!
1.end in close proximity to capillaries 2. contain secretory vesicles in ALL parts of the neuron |
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Herring Bodies
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10-30nm Herring Bodies
Dilations of the axonal endings containing neurosecretory granules ADH & Oxytocin |
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PITUICYTE
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• glial cell
• branching cytoplasm • support function |
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THYROID GLAND:
hormones |
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THYROID FOLLICLE
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cyst-like 0.2-1mm
lined with cuboidal epithelium = Follicular Cells filled with colloid = Thyroglobulin (glycoprotein) Extracellular storage |
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EM: thyroid
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Parafollicular cells (C cells)
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PARATHYROID GLAND
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parathyroid gland is essential for life needs ot be conserved in thyroid cells
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PTH Functions
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Parathyroid Gland Histology
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ADRENAL GLAND
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ADRENAL GLAND (CORTEX)
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zona glomerulosa
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zona fasciculata
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zona reticularis
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ADRENAL GLAND (MEDULLA)
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Chromaffin cells (modified neurons)
sinusoidal capillaries connective tissue Presynaptic sympathetic nerve fibres (axons) ganglion cells (modulate secretion) |
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CHROMAFFIN CELLS
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MEDULLA = sympathetic ganglion
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