Histology of the Endocrine System

Question 1

3 parts of the adenohypophysis

Answer 1

PARS DISTALIS (distal region):

• majority of the pituitary bulk
• chromophobe cells and chromophil cells (acidophils/alpha cells & basophils/beta cells)

PARS TUBERALIS (tubular region):

• part of the sheath extending up from the pars distalis which joins with the pituitary stalk (or infundibulum)
• poorly understood function
• receives endocrine signaal in the form of TSHB, informing the pars tuberalis of the photoperiod (length of day), regulated by melatonin secretion in response to light information transmitted to the pineal gland

PARS INTERMEDIA (intermediate region):

• between the pars distalis and the posterior pituitary (neurohypophysis)
• boundary between anterior and posterior pituitaries

Question 2

2 parts of the neurohypophysis

Answer 2

PARS NERVOSA (neural lobe):

• majority of the posterior pituitary bulk
• storage site of oxytocin and vasopressin (which were secreted by the hypothalamus)
• includes Herring bodies and pituicytes

Question 3

Structures found in the posterior pituitary that are the temporary storage sites of ADH/vasopressin and oxytocin; represent the terminal end of axons from the hypothalamus

Answer 3

Herring bodies (neurosecretory bodies)

Question 4

Neuroglial of the posterior pituitary that assist in the storage and release of the neurohypophyseal hormones (ADH/vasopressin and oxytocin)

Answer 4

Pituicytes

Question 5

Pars distalis cell:

• acidophil
• secretes PROLACTIN (PRL or lactotropin)

Answer 5

Lactotroph

Question 6

Pars distalis cell:

• acidophil
• secretes GROWTH HORMONE (GH, somatotropin, or STH)

Answer 6

Somatotroph

Question 7

Pars distalis cell:

• basophil
• secretes LUTEINIZING HORMOMN (LH, lutropin, or ICSH)

Answer 7

Gonadotroph

Question 8

Pars distalis cell:

• basophil
• secretes FOLLICLE-STIMULATING HORMONE (FSH)

Answer 8

Gonadotroph

Question 9

Pars distalis cell:

• basophil
• secretes THYROID-STIMULATING HORMONE (TSH or thyrotropin)

Answer 9

Thyrotroph

Question 10

Pars distalis cell:

• basophil
• secretes ADRENOCORTICOTROPHIC HORMON (ACTH or corticotropin)

Answer 10

Corticotroph

Question 11

Pars intermedia cell:

• chromophobic
• secretes MELANOCYTE-STIMULATING HORMONES (MSHs, melanotropins, or intermedins)

Answer 11

Melanotrophs (or melanotropes)

Question 12

Secretes melatonin, a hormone that regulates

daily body rhythms and day/night cycle secretion

Answer 12

Pineal gland

Question 13

Thyroid cells that secrete TH

Answer 13

Follicular cells

Question 14

Thyroid cells that secrete calcitonin

Answer 14

Parafollicular cells (or C cells)

Question 15

Parathyroid cells that secrete PTH

Answer 15

Chief cells

Question 16

Parathyroid cells that appear at the onset of puberty, but have no known function

Answer 16

Oxyphil cells

Question 17

Lymphatic organ considered as the graveyard of worn-out RBCs

Answer 17

Spleen

Question 18

A specialized primary lymphoid organ of the immune system where T cells (or T lymphocytes) mature; site of the characteristic Hassal corpuscle - a composition of granular cell(s) encapsulated by epithelioid cells (unknown function); ABSENT lymphoid nodules or germinal centers

Answer 18

Thymus

Question 19

Isolated masses of closely packed granular cells with epithelioid cell capsule (epithelioreticular cells) of unknown function found in the thymus that may produce the hormones THYMOSIN and THYMOPOIETIN

Answer 19

Hassal corpuscle

Question 20

Portion of white pulp in viewing the spleen - largely populated by T cells and surround central arteries within the spleen

Answer 20

Periarterioloar lymphoid sheath (PALS)

PALS T-cells are presented with blood-borne antigens via myeloid dendritic cells