Term
| Name the three mechanisms by which substances exert a control in the body: |
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Definition
| Parocrine, Endocrine, Autocrine |
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Term
| Common characteristics of endocrine organs |
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Definition
- possess no ducts
- secrete directly into vascular system
- rich blood supply (endothelium is fenestrated, except in testis where it is non-fenestrated)
- target organ responds selectively to circulating hormone
- reacts to stimulation or suppression |
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Term
| 1. Steroid secreting cells (general characteristics) |
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Definition
- arise embryologically from mesoderm
- abundant smooth endoplasmic reticulum
- mitochondria are large and have extensively developed cristae
- contain lipid droplets which are characterized by presence of free cholesterol and cholesterol esters and no demonstrable limiting membrane
- enzymes for various steps in steroidogenesis are present in distinct organelles
no stored hormone steroids synthesized and released from cell upon stimulation |
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Term
| 1. Steroid secreting cells (general characteristics) |
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Definition
- arise embryologically from mesoderm
- abundant smooth endoplasmic reticulum
- mitochondria are large and have extensively developed cristae
- contain lipid droplets which are characterized by presence of free cholesterol and cholesterol esters and no demonstrable limiting membrane
- enzymes for various steps in steroidogenesis are present in distinct organelles
no stored hormone steroids synthesized and released from cell upon stimulation |
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Term
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Definition
| an outer cortex surrounds a central medulla |
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Term
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Definition
Function
zona glomerulosa (mineralocorticoids)
- aldosterone
zona fasciculata. zona reticularis (glucocorticoids)
- cortisol in the human
b. Blood supply
- multiple arteries supply the gland, forming a plexus in the capsule
- cortical arteries arise from capsular plexus forming sinusoids while others
pass directly through the cortex to the medulla (in a few cases)
multiple venules join to form large central veins adrenal vein
c. Histogenesis of adrenal glands
- embryology cortex develops from coelomic mesoderm
fetus:
a fetal cortex develops (occupies 80% of the inner gland)
- a permanent cortex (occupies 20% of the outer part of the gland) after birth, fetal
cortex degenerates and permanent cortex enlarges
Cell origin of cortex--cortical cells appear to arise peripherally (near sub glomerulosa) and move inward (centripetally) |
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Term
| Testis, interstitial cells of testis (Leydig cells) |
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Definition
- located in interstitium
- synthesize and secrete testosterone
- ovoid to polygonal in shape with a large nucleus
- light staining, vacuolated cytoplasm (lipid droplets)
- contain lipochrome pigment
- granules crystals of Reinke –function is unknown |
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Term
| Testis, interstitial cells of testis (Leydig cells) |
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Definition
- located in interstitium
- synthesize and secrete testosterone
- ovoid to polygonal in shape with a large nucleus
- light staining, vacuolated cytoplasm (lipid droplets)
- contain lipochrome pigment
- granules crystals of Reinke –function is unknown |
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Term
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Definition
- estrogen synthesis depends on complex intereactions between the two gonadotropins and between theca interna and granulosa cells
- Theca interna cells: respond to LH by producing large amouts of androstenedione and testosterone (precursors of estrogen); the cells have little aromatase activity (can produce little estrogen)
- Granulosa Cells: synthesize aromatase in response to FSH (can transform androgens from theca interna cells to estrogen).
- progesterone produced by corpus luteum
- lutein cells contain lipid droplets, abundant smooth endoplasmic reticulum,
- mitochondria with tubular cristae |
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Term
| Kidney, juxtaglomerular apparatus (JGA) |
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Definition
• Modified myoepithelial cell in wall of afferent arteriole to glomerulus and a few also
• in efferent arteriole
• granular cells
• cytoplasmic granules stain with PAS or Bowie's ethyl violet
• secretes renin |
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Term
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Definition
A. afferent and efferent arteriole
B. macula densa (distinct region.of Thick Ascending limb of the loop of Henle (TALH)
C. extraglomerular mesangium
D. JG cells |
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