Gland histology Flashcards

1
Q

Pituitary have very cellular and fibrous/nervous tissue. Which parts are which and what do they include?

A

Anterior= Cellular: Distal lobe + Intermediate lobe + Tuberal Lobe

Posterior = fibrous/nervous tissue : neural lobe + pituitary stalk + median eminence

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2
Q

Where does the pituitary sit in relation to the skull?

A

In the sella turcica; cavity of the sphenoid bone

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3
Q

How many cell types are there in the anterior pituitary? How are they identified?

A

5 cell types based on staining characteristics: acidophils, basopils and chromophobes (don’t tak up stain)

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4
Q

in endocrine glands, the key components of the parenchyma are:

A

endocrine secreatory cells + capillary plexu

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5
Q

Somatotrophs in the anterior pit make up 50%. What do they release?

What is their releasing factor?

A

Somatotrophs release Growth hormone

releasing factor = GNRH (+) or GIH/Somatostatin (-)

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6
Q

What cell types in ant pit are acidophilic?

A

somatotrophs (release GH)

Lactotrophs (release Prolactin)

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7
Q

Lactotrophs located in the anterior pit release what cell?

What is their releasing factor?

A

Lactotrophs release Prolactin

releasing factor = Prolactin release-inhibiting Hormone or PIH

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8
Q

Ant Pit has corticotrophs that release what?

releasing factor?

A

release ACTH

factor = Corticotrophin releasing hormone (CRH)

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9
Q

Thyrotrophs located in the ant pit release what hormone?

releasing factor?

A

release thyroid stimulating hormone or TSH

Releasing factor is Thyroid Releasing Hormone or TRH

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10
Q

Gonadotrophs in the anterior pit release what?

Releasing factor?

A

Gonadotrophs reease FSH and LH

controleed by GnRH

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11
Q

What cell types stain basophilic in the ant pit?

A

Corticotrophs

Thyrotrophs

Gonadotrophs

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12
Q

posterior pituitary contains nonmyelinatedaxons of neurons located in the supraoptic and paraventricular nuclei of the______. The axons end on capillaries within the _____

A

hypothalamus

neural lobe.

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13
Q

In posterior pituitiary, a dilation is visible at the terminal end of the axon adjacent to the capillary . The dilation is filled with neurosecretion and is called a

A

Herring body

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14
Q
A
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15
Q

the hormones released at the axon terminals in posterior pituitary

A

Oxytocin and vasopressin along with a carrier protein called neurophysin

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16
Q

In posterior pit, prominent nuclei observable within the neural lobe belong to supporting glial cells called

A

pituicytes.

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17
Q

surround the pituitary stalk drain the capillary plexus in the median eminence.

A

Long portal vessels

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18
Q

The long portal vessels and the two capillary plexuses comprise the

A

hypothalamo-hypophyseal portal system

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19
Q

Long portal vessels can be damaged by severe head trauma resulting in atrophy of the

A

anterior pituitary.

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20
Q

A________ is the primary tumor of the anterior pituitary gland. Enlargement of the tumor may compress the optic chiasm. In addition, the tumor secretes excessive amounts of hormone that cause various endocrine syndromes.

A

benign pituitary adenoma

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21
Q

The lobes of the thyroid gland are located on either side of the inferior aspect of the thyroid cartilage lamina and the ______. The lobes are connected across the midline by an _______.

A

superior end of the trachea

isthmus

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22
Q
A
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23
Q

Within the lobules are thyroid follicles or secretory acini. These are epithelial lined spaces containing variable amounts of fluid called

A

colloid.

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24
Q

HOw is the thyroid different from other endocrine glands?

A

thyroid gland stores large amounts of inactive hormone within the follicles

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25
Q

The simple epithelium of the thyroid follicle is organized so that the ______ end of the cells is adjacent to the lumen of the follicle and the _____ end sits on a basement membrane that becomes the external surface of the follicle.

A

apical

basal

26
Q

The other secretory cell type in the thyroid gland is the ________which are larger then follicle epithelial cells and harder to distinguish because of their pale staining characteristics.

A

C cell or parafollicular cell

27
Q

What do thyroid epithelial cells secreate and whre are they located?

A

on the wall of thyroid follicles

Thyroglobulin, Triiodothyronine (T3), Thyroxine (T4)

28
Q

Where are parafollicular C cells located and what do they secreate?

A

Space between thyroid follicles

Calcitonin

29
Q

What is the vascular supply to the thyroid gland

A

Branches from the subclavian and external carotid arteries supply the thyroid gland.

30
Q

Most thyroid tumors are derived from ______ (adenocarcinomas).

A

follicle epithelial cells

31
Q

______ is characterized by hyperplasia and hypertrophy of thyroid epithelial cells. Excess thyroid hormone is produced and released resulting in increase in basal metabolic rate.

A

Thyrotoxicosis

32
Q

are small oval masses on the dorsal side of the thyroid gland. Usually there are four. They have a thin fibrous capsule.

A

parathyroid glands

33
Q

_____are a constant feature of the parathyroid gland. They appear during puberty and gradually increase in number until the fourth decade when their numbers remain constant

A

Adipocytes

34
Q

The chief cells in the parathyriod produce_______. When calcium balance is normal, over 80% are in the resting phase

A

parathyroid hormone

35
Q

Rare before puberty, ______increase in number during early adult life and are numerous in the elderly when they can form nodules in the gland.

A

oxyphil cells

36
Q

What do chief cells in the parathryoid secreate?

A

Parathyroid hormone

37
Q

The most common tumor of the parathyroid is the _______ These tumors produce excess parathyroid hormone that leads to primary hyperparathyroidism.

A

parathyroid adenoma.

38
Q

Parathyroid hyperplasia due to increase in ________number occurs when serum calcium levels are persistently low. This leads to secondary hyperparathyroidism.

A

chief cell

39
Q

Adrenal gland: The cortex secretes _____, while the medulla is a neuroendocrine gland _________. The gland is surrounded by a fibrous capsule and contains a rich capillary bed.

A

steroid hormones

secretingvasoactive amines

40
Q

Adrenal Cortex The cortex is the external layer of the gland. It consists of three zones, the

A

zona glomerulosa, zona fasciculata and zonareticularis

41
Q

secretory cells in the adrenal cortex have the morphology that is characteristic of steroid secreting cells for these three reasons

A

There is

1) abundant smooth endoplasmic reticulum, the site of steroid synthesis,
2) abundant mitochondria with tubulovesicular cristae, the site of cholesterol synthesis and
3) membrane bound lipid droplets, the raw material for making steroid hormones.

42
Q

Describe the organization of the zona Glomerulosa

A

Beneath capsule, narrow with Small compact cells arranged in clumps surrounded by fine fibrous tissue

Cells contain fewer lipid droplets

43
Q

What does the zona Glomerulosa secreate?

What controls it’s secreations?

A

Mineralocorticoids, e.g. aldosterone, deoxycorticosteron

Controlled by RAAS

44
Q

Describe the morphology of the Zona Fasciculata

A

Widest zone Cells in vertical columns separated by capillaries

Large cells with clear, vacuolated cytoplasm

45
Q

What does the zona Fasciculata secreate and what is it controlled by

A

Secreates Glucocorticoids, e.g. Cortisol, Corticosterone

Is controlled by ACTH

46
Q

Describe the morphology of the Zona Reticularis

A

Innermost zone, narrow Small cells in anastomosing cords and columns

Presence of lipofuscin pigment in cells

47
Q

What does the zona reticularis secreate?

A
48
Q

The adrenal medulla occupies the center of the gland. Secretory cells are _________ originating from neural crest.

A

neuroendocrine cells

49
Q

The medulla secretory cells have_____ nuclei and finely granular cytoplasm. They are arranged in clumps, cords and columns surrounded by ____

A

large

abundant capillaries

50
Q

What does the medulla release?

A

Some of the cells secrete epinephrine (adrenaline) and other neuroepinephrine (noradrenaline).

51
Q

Where are hormones stored in teh adrenal medulla?

What mediates their release?

A

stored intracellularly and released in small amounts.

Release of the hormones is mediated by sympathetic nervous system.

52
Q

The most common tumor of the adrenal cortex is an _______. When functional they can cause hyperadrenalism.

A

adrenal cortical adenoma

53
Q

is a benign tumor of adrenal medulla cells the produces excessive amounts of epinephrine and norepinephrine.

A

A pheochromocytoma

54
Q

is a highly malignant tumor originating from precursor cells of the medulla

A

A neuroblasoma

55
Q

Pancrease: The endocrine cells are arranged in clusters of cells scattered throughout the pancreas. These clusters are called

A

pancreatic islets or Islets of Langerhans.

56
Q

describe morphology of the pancreas

A

The islets are embedded within the exocrine parenchyma. The pancreas has a thin fibrous capsule. Septa extend from the capsule into the parenchyma dividing it into lobules.

57
Q

The pancreatic islets contain several types of secretory cells that are most accurately identified by immunostaining for the hormone product. The most accurate classification is to name it with reference to

A

the hormone it produces.

58
Q

The islets are innervated by sympathetic and parasympathetic nerve fibers.

_______input inhibits insulin release, while_______ input increases insulin and glucagon secretion.

A

Sympathetic

parasympathetic

59
Q

What is all secreated in the pancreas?

A

Insulin (beta cells)

glucagon (alpha cells)

Somatostatin (delta)

Pancreatic polypeptide

VIP

60
Q

blood supply of the pancreas

A

Branches of the splenic, gastroduodenal and superior mesenteric arteries supply the pancreas

61
Q

Describe the capillary plexus system in the pancreas

A

Each islet has its own capillary plexus that originates from small arterioles outside the islet. The capillaries in the islets are fenestrated.

62
Q

:Individuals with chronic pancreatitis or cystic fibrosis my develop______ because of destruction of islet cells.

A

diabetes mellitus