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090713 umar ahmad, histology endocrine
1. Histology of Endocrine System
UMAR AHMAD
MODERATOR: PROF. DR. FAUZIAH OTHMAN
Department of Human Anatomy
Faculty of Medicine & Health Sciences
Universiti Putra Malaysia.
PREMEDIC MESIR 2013
Aug 26, 2013 Umar Ahmad 1
8. Cells and hormones of the anterior pituitary
LM
staining
Cell type Hormone Releasing (+) or
inhibiting (-) horm.
Acidophil Somatotrope Growth hormone (GH)
= somatotropin
GHRH (+)
Somatostatin (-)
Acidophil Mammotrope
= lactotrope
Prolactin (PRL) [Dopamine (-)
estrogen (+)]
Basophil Thyrotrope Thyroid stimulating
hormone (TSH)
= thyrotropin
TRH (+)
Basophil Gonadotrope Luteinizing hormone
(LH), follicle stimulating
hormone (FSH); both =
gonadotropin
GnRH (+)
Basophil
(human)
Corticotrope Adrenocorticotropin
(ACTH) = corticotropin
CRH (+)
A.K. ChristensenAug 26, 2013 Umar Ahmad 8
9. Pituitary, low power LM
Humio Mizoguti, Kobe Univ Sch Med, slide 515
Aug 26, 2013 Umar Ahmad 9
10. Anterior pituitary, LM drawing
Image of cords of
cells in anterior
pituitary removed.
Original here:
Bailey's textbook
of histology.
72(700)6
Aug 26, 2013 Umar Ahmad 10
11. Anterior pituitary, LM, trichrome stain
Stan Erlandsen Medical Histology slide collection, slide MH 9/B/4Aug 26, 2013 Umar Ahmad 11
12. Anterior pituitary, LM, H&E stain
Basophil
Stan Erlandsen Medical Histology slide collection, slide MH-9B3
Aug 26, 2013 Umar Ahmad 12
17. Cytoplasm of prolactin-secreting
cell (lactotrope), EM
Secretory
granule
Golgi
Rough ER
Marilyn Farquhar in Memoirs of the Society for Endocrinology
Aug 26, 2013 Umar Ahmad 17
18. Golgi and secretory granules, EM
Golgi
Granule
Mitochondrion Nucleus
Marilyn Farquhar in Memoirs of the Society for Endocrinology
Aug 26, 2013 Umar Ahmad 18
19. Exocytosis of prolactin granules, EM
Marilyn Farquhar in Memoirs of the Society for Endocrinology
Aug 26, 2013 Umar Ahmad 19
20. Regulation of the anterior pituitary
Hedges, 1987
Aug 26, 2013 Umar Ahmad 20
21. Regulation of anterior pituitary, detail
O'Riordan et al 1988, p 47
Aug 26, 2013 Umar Ahmad 21
22. SEM of pituitary:
portal veins,
capillaries, corrosion
vascular cast
Murakami T, 1975, Archivum Histologicum Japanicum 38:151-168
Aug 26, 2013 Umar Ahmad 22
23. Posterior pituitary
• Hormones
– Antidiuretic hormone (ADH = arginine vasopressin)
– Oxytocin
• Neurosecretion
– Hormones synthesized as part of larger proteins
(neurophysins) in neuron cell bodies of hypothalamus.
– Transported in axons to pars nervosa (hormone cleaved
from neurophysin).
– Hormone secreted from axon terminals into capillaries.
• Pituicytes
– Specialized glia of pars nervosa.
Aug 26, 2013 Umar Ahmad 23
27. Pars intermedia,
between anterior
and posterior
pituitary, human,
LM.
Poorly developed and of
doubtful function in
humans.
Intermedia
Anterior Posterior
Humio Mizoguti, Kobe Univ Sch Med, slide 516
Aug 26, 2013 Umar Ahmad 27
28. Pars intermedia, rat pituitary, LM
Rathke'spouch
A.K. Christensen
Aug 26, 2013 Umar Ahmad 28
32. Human adrenal, low power LM
Bailey’s Histology
Aug 26, 2013 Umar Ahmad 32
33. Adrenal cortex
• Zona glomerulosa
– Main hormone: Aldosterone (a mineralocorticoid).
– General function: Maintain blood electrolyte balance.
– Main control: Angiotensin II.
• Zona fasciculata
– Main hormone: Cortisol (a glucocorticoid).
– General function: Includes regulating glucose and fatty
acid metabolism, and response to stress.
– Main control: Pituitary ACTH.
• Zona reticularis
– Hormones: Some cortisol and androgens.
– Function and control: Similar to zona fasciculata.
Aug 26, 2013 Umar Ahmad 33
34. Adrenal cortex, human, LM
Hadley Kirkman slide collection, slide K285
Aug 26, 2013 Umar Ahmad 34
35. Adrenal cortex, human, H&E, LM
Humio Mizoguti, Kobe Univ Sch Med, slide 547
Aug 26, 2013 Umar Ahmad 35
36. Adrenal blood vessels
Image of adrenal
gland vasculature
removed. Original
here: Junqueira
and Carneiro, 10th
ed., 2003, page
414, fig 21-2.
Aug 26, 2013 Umar Ahmad 36
43. Adrenal medulla
• Hormones
– Epinephrine (adrenalin) and norepinephrine (noradrenalin),
both catecholamines. Two cell types, one for E and one for N.
– General function: Acute response to stress.
– Main control: Preganglionic sympathetic innervation.
• Embryonic source
– From neural crest cells, same as postganglionic sympathetic
neurons. Although adrenal medulla cells do not have
dendrites or axons, they behave like postganglionic
sympathetic neurons, releasing norepinephrine/epinephrine in
response to preganglionic sympathetic stimulation.
• Also called "chromaffin cells"
– Cells of the adrenal medulla are examples of "chromaffin
cells," containing catecholamine granules that stain brown
with potassium dichromate. Neurons of sympathetic ganglia
are also chromaffin cells. The term is used in pathology.Aug 26, 2013 Umar Ahmad 43
45. EM of adrenal medulla: norepinephrine and epinephrine cells
Nucleus
Nucleus
Nucleus
Norepinephrine
Epinephrine
Stan Erlandsen Medical Histology Slide Collection, slide MH 9/G/2-P
Aug 26, 2013 Umar Ahmad 45
46. Production of norepinephrine and epinephrine in the cytosol
Regents of the University of MichiganAug 26, 2013 Umar Ahmad 46
49. Thyroid gland
• Thyroid follicles
– Thyroid hormones: thyroxine (T4), triiodothyronine (T3).
– Synthesis: A very large protein, thyroglobulin (660 kDa), is
synthesized and then secreted into the follicle lumen. It is later
taken up and broken down (with lysosomes) to yield T4 and T3.
– General function: To increase the body's metabolic rate.
– Main control: Pituitary TSH.
• Parafollicular cells (= C-cells)
– Hormone: Calcitonin.
– General function: Lower serum calcium.
– Main control: Serum calcium level.
Aug 26, 2013 Umar Ahmad 49
54. Thyroid capillary beds, corrosion vascular cast, SEM
Stan Erlandsen Medical Histology slide set, slide MH 9/D/5
Aug 26, 2013 Umar Ahmad 54
55. Production of
thyroid hormones
by a follicular cell
Synthesize
thyroglobulin and then
secrete it into the
colloid. Iodinate
tyrosine residues on
thyroglobulin. When
stimulated by pituitary
TSH, take up the
thyroglobulin and
break it down in
lysosomes to release
thyroid hormones T3
and T4.
Colloid
Modified from Junqueira and Carneiro, 10th ed., 2003, page 426, fig. 21-19 by R. Mortensen
Aug 26, 2013 Umar Ahmad 55
57. Causes of goiter
(increase in thyroid size)
Rugh and Patton 1965, Physiology and biophysics, 19th ed
Aug 26, 2013 Umar Ahmad 57
58. Functional states of
thyroid follicles
Normal
Underactive = hypoactive
Overactive = hyperactive
Normal
Image of thyroid
follicles removed.
Original here:
0'Riordan, 2nd ed,
p 160.
Aug 26, 2013 Umar Ahmad 58
60. Overactive (hyperactive) thyroid follicles
Medical Histology atlas by Stanley L. Erlandsen and Jean E. MagneyAug 26, 2013 Umar Ahmad 60
61. Thyroid gland
• Parafollicular cells (= C-cells)
– Hormone: Calcitonin.
– General function: Lowers serum calcium.
– Main control: Serum calcium level.
Aug 26, 2013 Umar Ahmad 61
62. C cell location in thyroid
Hedge 1987
Aug 26, 2013 Umar Ahmad 62
63. C-cell in thyroid follicular epithelium, LM
C-cell
A.K. Christensen
Aug 26, 2013 Umar Ahmad 63
64. Immunocytochemical localization of calcitonin in C cells, LM
C cell
Stan Erlandsen Medical Histology slide collection, slide MH 9/D/8
Aug 26, 2013 Umar Ahmad 64
Comparison of endocrine, paracrine, neurosecretory and neurotransmission. From O'Riordan et al., 2nd ed, page 5. 1990C26(2).jpg. 72(700)6.
The pituitary is located below the brain, in the hypophyseal fossa of the sphenoid bone. From Ciba Collection of Medical Illustrations by Frank H. Netter. 1973E25(55).jpg.
Development of the pituitary. From Ross and Pawlina, 5th ed, 2006, fig 21.4, pg 690. enh_Ross5-f21-4-p690.jpg.
Pituitary nomenclature. From Ross and Pawlina, 5th ed, 2006, fig 21.3b, pg 689. enh_Ross5-f21-3-p689.jpg.
LM, human pituitary, at low power. From Japanese slide set ( Humio Mizoguti, Kobe Univ Sch Med ), slide 515 (= 57-1). Japan515-L.jpg. 72(550)6.
Colored drawing of cords of cells in the anterior pituitary (= pars distalis). Between the cords are sinusoids (large capillaries). The acidophils (making either GH or prolactin) are orange, while the basophils (source of FSH, LH, TSH or ACTH) are purple or light blue. From Bailey's textbook of histology. 1973J23(21).jpg. 72(700)6.
LM, anterior pituitary, stained with a trichrome stain. Acidophils (making growth hormone or prolactin) are red, and basophils (making thyroid stimulating hormone, LH/FSH, or ACTH) are blue or grayish. Note the sinusoid (large capillary), filled with red blood cells. From Stan Erlandsen Medical Histology slide collection, slide MH 9/B/4. MH-9B4-L.jpg. 72(650)6.
LM, human pituitary, stained with H&E. From Stan Erlandsen Medical Histology slide set, slide MH-9B3. MH-9B3-L.jpg. 72(600)6.
LM immunocytochemistry (ICC) to localize growth hormone in the rabbit anterior pituitary. The darkly-stained cells are somatotropes, that produce growth hormone and have abundant secretory granules in their cytoplasm, giving strong immunoreactivity for antibodies against growth hormone. Horseradish peroxidase (HRP)/DAB was used as the marker (with the Vector ABC kit). Slide done during the 3 hr ICC demo run carried out by students in AKC’s Morphology for Molecular Biologists course. 1998D07(33)C.jpg. 72(650)6.
Fluorescence immunocytochemistry to localize cells (gonadotropes) making LH/FSH in the rat anterior pituitary. The primary antibody was against the ß-subunit of luteinizing hormone (LH), and fluorescein was on the secondary antibody as a marker. LH is in secretory granules in the cytoplasm of the two gonadotrope cells. Semithin frozen section (about 2 µm thick) of lightly fixed but unembedded pituitary. Done by AKC in 1983. Later used as a cover for the journal Microscopy and Microanalysis, volume 3, number 6, November/December 1997. 1983B05(75)C.jpg. 72(650)6.
EM of rat anterior pituitary. A somatotrope (cell that makes growth hormone) has abundant large, round secretory granules. A gonadotrope (LH and FSH), has small granules and swollen rough ER. A lactotrope (prolactin), has sparse, large, irregularly-shaped granules. EM taken by Larry Kahn, in AKC lab, in 1980. LEK11-06-17-L.jpg. 72(700)6.
Pathway of secretion for prolactin in lactotropes (=mammotropes) in the anterior pituitary. Proteins synthesized in the rough ER pass to the Golgi complex, where they are formed into granules. Upon stimulation, the granules are released. From Fawcett Histology, ed 11, p 486. 1996C18(13).gif. 72(700).
EM of cytoplasm in a lactotrope of the rat anterior pituitary, showing rough endoplasmic reticulum, Golgi complex (Gc), and secretory granules (sg, ag). From chapter by Marilyn Farquhar in Memoirs of the Society for Endocrinology, number 19, pp 79-124, fig 2, p 86. 1973E30(1).jpg. 72(700)6.
EM of secretory granule formation in the Golgi complex (Gc) of a lactotrope (making prolactin), in rat anterior pituitary. ic=inner cisterna of Golgi, m=mitochondria, n=nucleus. From chapter by Marilyn Farquhar in Memoirs of the Society for Endocrinology, number 19, pp 79-124, figs 2 and 3, p 88. 1973E30(2).jpg. 72(700)6.
EM showing release of prolactin granules (exocytosis) from the surface of a lactotrope (=mammotrope) in the anterior pituitary of a lactating rat. From chapter by Marilyn Farquhar in Memoirs of the Society for Endocrinology, number 19, pp 79-124, fig 5, p 89. 1973E30(3).jpg.
Regulation of the anterior pituitary by releasing hormones produced by neurons in the hypothalamus. From Hedges 1987, p. 86. 1996C18(24).gif. 72(700).
Regulation of the pituitary gland. The anterior pituitary is regulated by neurosecretion from the hypothalamus. Neurons produce releasing hormones that pass along their axons to terminals in the median eminence. There the hormones pass into capillaries, which carry the hormones through portal veins to capillary beds of the anterior pituitary, where the pituitary cells are stimulated. The hormones of the posterior pituitary (oxytocin, vasopressin), on the other hand, are made by neurosecretory cells in the hypothalamus, pass all the way to the posterior pituitary in axons, and are released there into capillaries that carry them out to the body. From O'Riordan et al 1988, p 47. 1997C27(2).jpg. 72(700)6.
SEM of a vascular corrosive cast of capillaries and veins on the inferior aspect of the anterior pituitary and median eminence of a rat. Neurosecretory neurons in the hypothalamus send releasing hormones down their axons to terminals in the median eminence (labeled M), where the hormones are released into capillaries. The blood from these capillaries travels through hypothalamo-hypophyseal portal veins (labeled P) to reach the anterior pituitary (labeled A), where the releasing hormones regulate the cells that make pituitary hormones. From Murakami T, 1975. Pliable methacrylate casts of blood vessels: use in a scanning electron microscope study of the microcirculation of rat hypophysis. Archivum Histologicum Japanicum 38:151-168. 1976K02(1).jpg. 72(700)6.
Regulation of the pituitary gland. The anterior pituitary is regulated by neurosecretion from the hypothalamus. Neurons produce releasing hormones that pass along their axons to terminals in the median eminence. There the hormones pass into capillaries, which carry the hormones through portal veins to capillary beds of the anterior pituitary, where the pituitary cells are stimulated. The hormones of the posterior pituitary (oxytocin, vasopressin), on the other hand, are made by neurosecretory cells in the hypothalamus, pass all the way to the posterior pituitary in axons, and are released there into capillaries that carry them out to the body. From O'Riordan et al 1988, p 47. 1997C27(2).jpg. 72(700)6.
LM, posterior pituitary (= pars nervosa). Note the promient nuclei of pituicytes, which are glial cells. In this histological preparation you can't make out axon terminals (containing oxytocin or vasopressin) derived from neurosecretory neurons in the hypothalamus. There are no neuron cell bodies in the posterior pituitary. Taken by AKC from a Burton L. Baker LM slide (hypoxed female rat). 1980C12(154)CL.jpg. 72(700)6.
LM drawing of posterior pituitary, specially stained to show neurosecretory material (oxytocin and arginine vasopressin [= anti-diuretic hormone, ADH]) in axon terminals (labeled "p"). The hormones are released into nearby capillaries (labeled "s"). Pars nervosa of opossum. "pit" = pituicyte cell bodies. "ax" = axons. "HB" = Herring body. From Weiss Histology, ed 5, p. 1070. 1985C12(30).jpg. 72(700)6.
LM, human pituitary, showing anterior (at left) and posterior (at right) lobes. The pars intermedia ("intermediate lobe") is very poorly developed in humans, and consists merely of a modest layer of darker cells lying against the posterior lobe, to the right of the white cleft between the anterior and posterior lobes. From Japanese slide set (Humio Mizoguti, Kobe Univ Sch Med), slide 516 (= 57-2). Japan516.jpg. 72(600)6.
LM, rat pituitary, showing the prominent pars intermedia seen in the pituitary of non-human mammals. Anterior pituitary, pars intermedia, and posterior pituitary are labeled. Taken by AKC from a Burton L. Baker LM slide. 1980C28(59)CL.jpg. 72(650)6.
Location and appearance of the human adrenal. From the Ciba Collection of Medical Illustrations, by Frank H. Netter, vol 4, p 79. 1975G24(27).jpg. 72(700)6.
LM drawing of human adrenal. Note that the medulla is absent in the lobes extending to right and to left. From Bailey's Histology (camera lucida drawing of section at very low power). 1973I08(42).jpg. 72(700)6.
LM of human adrenal cortex and medulla, which are seen more clearly in this preparation than is usually the case for human material. The capsule, the three layers of the cortex (zona glomerulosa, zona fasciculata, and zona reticularis), and the medulla are labeled. From Hadley Kirkman slide collection, slide K285 (labels added digitally). K285-L.jpg. 72(700)6.
LM, human adrenal cortex, stained with H&E. From left to right, capsule , zona glomerulosa, zona fasciculata, zona reticularis, medulla. From Japanese slide collection(Humio Mizoguti, Kobe Univ Sch Med), slide 547 (= 57-8). Japan547-L.jpg. 72(700)6.
Vasculature of the adrenal gland. From Junqueira and Carneiro, 10th ed., 2003, page 414, fig 21-2. EN-AdrenalVasc.jpg.
Adrenal vasculature, SEM of vascular corrosion cast. S = subcapsular capillary plexus, MA = medullary artery. From Virginia Black chapter, in Weiss Histology, 6th ed, p 1039. 1996D01(2).jpg. 72(700)6.
LM, human adrenal cortex, capsule and zona glomerulosa (at left). The right half of the picture is zona fasciculata. From Japanese slide set , slide 548 (=57-9). Japan548-L.jpg. 72(600)6.
LM, human adrenal, detail of zona fasciculata. From Japanese slide collection, slide 549 (= 57-10). Japan549-L.jpg. 72(600)6.
EM of adrenal zona fasciculata. The cells secrete the steroid hormone cortisol into the adjacent capillaries (labeled C). The cytoplasm has prominent smooth endoplasmic reticulum (SER). Lipid droplets (labeled D) in the cytoplasm contain cholesterol esters as substrates for steroid biosynthesis. From Stan Erlandsen Medical Histology slide collection, slide MH 9/F/4. MH-9F4.jpg. 72(700)6.
EM, cytoplasm of cell in zona fasciculata, human adrenal cortex. Extensive development of the smooth endoplasmic reticulum (SER), which has many of the enzymes for the synthesis of adrenal steroid hormones (such as cortisol). From Long and Jones 1967. 1976H30(31).jpg. 72(800)6.
LM, human adrenal, detail of (left to right) zona fasciculata, zona reticularis, and medulla. From Japanese slide collection ( Humio Mizoguti, Kobe Univ Sch Med ), slide 550 (= 57-11). Japan550-L.jpg. 72(600)6.
LM, human adrenal medulla, source of epinephrine and nor-epinephrine (= adrenaline and nor-adrenaline). There is some zona reticularis at the top of the picture (cells more reddish). The somewhat brownish appearance of the medulla is due to staining with potassium dichromate -- the cells that make norepinephrine and epinephrine are chromaffin cells. From Japanese slide collection (Humio Mizoguti, Kobe Univ Sch Med), slide 565 (= 57-13). Japan565-L.jpg. 72(600)6.
EM showing cells of the adrenal medulla. The medulla has two hormone-producing cell types, one making norepinephrine (at left, labeled NE), and one making epinephrine (at right, labeled E). Note that the secretory granules of the norepinephrine secreting cell are larger than those of the epinephrine cell. From Stan Erlandsen Medical Histology slide collection, slide MH 9/G/2-P. MH-9G2.jpg. 72(700)6.
Secretion of epinephrine or nor-epinephrine in the adrenal medulla. Note that the hormones are synthesized free in the cytoplasm, and then transported into the secretory granule. A given cell makes either norepinephrine or epinephrine, not both. From Junqueira and Carneiro, 10th ed., 2003, page 419, fig. 21-8. EN-MedullaCell.jpg.
Location of the thyroid, on the larynx and trachea. Original image from Grant's Atlas of Anatomy, 6th ed (1972), fig 529.1. 1973C27(37).jpg. 72(700)6.
Thyroid follicle, and the production of thyroid hormones (T4, T3) by way of thyroglobulin. The figure also shows the location of C cells, source of calcitonin. Modified from figure by Hedge 1987, p 102. 1996C18(8).jpg. 72(700)6.
LM, thyroid gland, at very low power. The gland is made up of follicles of various size and shape. From Hadley Kirkman (Stanford) slide collection, slide 18. K18.jpg. 72(600)6.
LM, thyroid follicles. Each follicle consists of a layer of thyroid follicular epithelial cells surrounding the colloid. From Stan Erlandsen Medical Histology slide collection, slide MH 9/D/6. MH-9D6.jpg. 72(600)6.
LM of thyroid follicles, stained with a triple stain. The epithelium has a normal appearance (not particularly high or low). From Hadley Kirkman (Stanford) slide collection, slide K27. K27.jpg. 72(600)6.
SEM of capillary bed around thyroid follicles. (P). A rich vasculature is characteristic of endocrine glands, such as the thyroid. SEM of corrosion vascular cast. From Stan Erlandsen Medical Histology slide set, slide MH 9/D/5. MH-9D5.jpg. 72(700)6.
Production of thyroid hormones in thyroid follicular epithelial cells. A large protein, thyroglobulin (composed of two identical 330 MW subunits), is secreted into the colloid, and iodine is added to tyrosine residues. Later, under pituitary TSH stimulation, the protein is taken up by the cells, and is degraded, releasing thyroid hormones T4 and T3 into nearby capillaries. From Junqueira and Carneiro, 10th ed., 2003, page 426, fig. 21-19. EN-ThyroidCell.jpg.
Thyroid follicular cell, EM. Rough endoplasmic reticulum (ER), Golgi complex (G), lysosomes (RB for residual bodies, DB for dense bodies), microvilli (Mv), nucleus (N) and lumen (Lu) of the follicle. From Porter and Bonneville, 1968, Fine structure of cells and tissues, 3rd ed, plate 30, p 83. 1971J21(19).jpg. 72(700)6.
Causes of goiter (enlargement of the thyroid gland). Usually involves chronic insufficient production of thyroid hormones. This causes pituitary to overproduce TSH in an effort to remedy the deficit, thus making the thyroid hyperactive (hypertrophy) and increasing the number of cells (hyperplasia). Experimental production by a goitrogen, thiouracil (blocks iodide oxidation by peroxidase). A defective pituitary, with overproduction of TSH, can also cause it. From Rugh and Patton 1965, Physiology and biophysics, 19th ed, p 1160. 1973J25(47).jpg. 72(800)6.
Thyroid functional states. Above, normal. Lower left, underactive (=hypoactive), with low epithelium and the accumulation of colloid. Lower right, overactive (=hyperactive), with tall epithelial cells, decreased colloid. From 0'Riordan, 2nd ed, p 160. 1990C26(23).jpg.
LM, thyroid, monkey. The follicles shown here appear hypoactive, since the follicular epithelium is very low, and the colloid is abundant. AKC, photographed from a commercial glycolmethacrylate section. 1974I10(39)C.jpg. 72(600)6.
Follicles in the thyroid gland. The thyroid gland shown here would appear to be somewhat hyperactive: (1) the follicular epithelial cells seem particularly large, and (2) the colloid in the follicles is depleted, suggesting it is being taken up rapidly for conversion to thyroid hormones. Red blood cells in small blood vessels between the follicles stain light pink in this preparation, which is unusual. From histology slide Medical Histology atlas by Stanley L. Erlandsen and Jean E. Magney, slide 9/D/3. MH-9D3.jpg.
Thyroid follicle, and the production of thyroid hormones (T4, T3) by way of thyroglobulin. The figure also shows the location of C cells, source of calcitonin. Modified from figure by Hedge 1987, p 102. 1996C18(8).jpg. 72(700)6.
C-cell (parafollicular cell) in the epithelium of a thyroid follicle. C-cells are often in the interstitial tissue between thyroid follicles. However, they may also be incorporated into the thyroid epithelium, where they share a common basement membrane, but are never in contact with the lumen. U-M virtual slide 218, at coordinates 3181x7811.
LM, immunocytochemical localization of parafollicular cells (= C cells), source of calcitonin in the thyroid gland. These cells are usually difficult to distinguish in histological preparations of thyroid, but the immunocytochemical staining for calcitonin makes them dark brown. These cells are usually seen between the follicles, but may also occur in the base of the follicular epithelium. From Stan Erlandsen Medical Histology slide collection, slide MH 9/D/8. MH-9D8.jpg. 72(700)6.
EM of thyroid parafollicular cell (C cell), source of calcitonin. Figure from Junqueira histology textbook. 1989B13(8).jpg. 72(700)6.
Location of the four parathyroid glands, on the back of the thyroid gland. From Junqueira and Carneiro, 10th ed., 2003, page 428, fig. 21-22. EN-ParathyGland.jpg.
LM, human parathyroid gland at very low power. The gland is essentially a solid mass of chief cells, source of parathyroid hormone. Also visible in this section are dark blood vessels, and white extracted lipid droplets. From Japanese slide set (Humio Mizoguti, Kobe Univ Sch Med), slide 542 (= 9-11). Japan542.jpg. 72(650)6.
Low power LM of parathyroid gland. Virtually all the cells seen here are chief cells (source of parathyroid hormone), but there is an oxyphil cell (arrow) just below the white space near the center of the field. 1992G23(55)C.jpg. 72(650)6.
SEM of capillary bed in parathyroid gland (P). A rich vasculature is characteristic of endocrine glands, such as the parathyroid. SEM of corrosion vascular cast. The vasculature of nearby thyroid follicles (T) is equally impressive. SV=superior thyroid vein branches. PV=parathyroid vein. Rat. From Murakami et al 1987, Arch Hist Jap 50:495, fig 2. 1989B13(21).jpg. 72(700)6.
LM, human parathyroid, H&E stain. In the left half of the field are the usual chief cells. At right is a large cluster of oxyphil cells. In the oxyphil cells, note the small, dense nuclei, and the clear, eosinophilic cytoplasm. The large white circles are extracted fat cells. Photograph taken of slide from U-M medical histology class set by AKC. 1992G23(50)CL.jpg. 72(650)6.
Oxyphil cell, parathyroid, drawn as it appears at the EM level. The cytoplasm of the cell is full of mitochondria. The function of this cell type is unknown. Drawing from Thomas Lentz atlas. 1989B13(3).gif. 72(800).