Block 3: Endocrine System

adenohypophysis

What is another name for the anterior pituitary?

neurohypophysis

What is another name for the posterior pituitary?

corticotrophs

Which pituitary cells produce ACTH?

ACTH

What hormone is produced by corticotrophs?

adrenal gland

What is the target organ of ACTH?

thyrotrophs

Which pituitary cells produce TSH?

TSH

What hormone is produced by thyrotrophs?

thyroid gland

What is the target organ of TSH?

gonadotrophs

Which pituitary cells produce FSH and LH?

FSH and LH

What hormones are produced by gonadotrophs?

reproductive organs

What are the target organs of FSH and LH?

mammotrophs

Which pituitary cells produce prolactin?

prolactin

What hormone is produced by mammotrophs?

mammary gland

What is the target organ of prolactin?

somatotrophs

Which pituitary cells produce somatotrophin / growth hormone?

somatotrophin / growth hormone (GH)

What hormone is produced by somatotrophs?

liver (IGF-1)

What is the target organ of somatotrophin / growth hormone in this lecture?

vasopressin (ADH)

Which hormone is produced by neurons in the hypothalamus and targets the kidney?

kidney

What is the target organ of vasopressin?

oxytocin

Which hormone is produced by neurons in the hypothalamus and targets the uterus and mammary gland?

uterus and mammary gland

What are the target organs of oxytocin?

ACTH

Which pituitary hormone stimulates the adrenal cortex to produce corticosteroids described as salt, sugar, and sex hormones?

TSH

Which pituitary hormone stimulates the thyroid gland to produce T3 and T4?

T3 and T4

What hormones does TSH stimulate the thyroid gland to produce?

FSH

Which hormone stimulates ovarian follicle development and spermatogenesis?

LH

Which hormone stimulates progesterone secretion, promotes ovulation, and stimulates testosterone secretion?

prolactin

Which hormone stimulates the mammary gland to produce milk?

somatotrophin / growth hormone

Which hormone stimulates liver IGF-1 production, protein deposition, cell reproduction, cartilage/bone growth, and fat utilization?

vasopressin (ADH)

Which hormone promotes water absorption by collecting tubules and ducts of the kidney?

oxytocin

Which hormone stimulates contraction of uterine smooth muscle and mammary myoepithelial cells?

pars distalis, pars tuberalis, pars intermedia

What are the three parts of the adenohypophysis?

pars distalis

Which part of the adenohypophysis contains chromophobes and chromophils?

chromophobes

Which relatively unstained cell group is found in the pars distalis?

acidophils

Which chromophils include somatotrophs and mammotrophs?

somatotrophs

Which acidophils produce growth hormone?

mammotrophs

Which acidophils produce prolactin?

pars tuberalis

Which part of the adenohypophysis contains basophilic gonadotrophs?

gonadotrophs

Which basophils of the pars tuberalis produce FSH and LH?

pars intermedia

Which part of the adenohypophysis contains Rathke cysts and melanotrophs?

Rathke cysts

What characteristic cysts are found in the pars intermedia?

melanotrophs

Which basophils of the pars intermedia produce MSH?

MSH

What hormone is produced by melanotrophs?

ectoderm of Rathke pouch

From what embryologic tissue does the adenohypophysis arise?

neural ectoderm of the diencephalon

From what embryologic tissue does the neurohypophysis develop?

colloid

What material is found within the Rathke cysts of the pars intermedia?

median eminence, infundibular stalk, pars nervosa

What are the three parts of the neurohypophysis?

median eminence

Which part of the neurohypophysis contains long axons associated with ADH and oxytocin?

ADH and oxytocin

What hormones are associated with the long axons of the median eminence?

median eminence

Which part of the neurohypophysis also contains short axons and axon terminals associated with hypothalamic inhibiting hormones?

infundibular stalk

What connects the median eminence to the pars nervosa?

pars nervosa

Which part of the neurohypophysis contains a fenestrated capillary plexus, pituicytes, axons, Herring bodies, ADH, and oxytocin?

fenestrated capillary plexus

What type of capillary plexus is present in the pars nervosa?

pituicytes

What supporting cell type is found in the pars nervosa?

Herring bodies

What characteristic structures are found along axons in the pars nervosa?

ADH and oxytocin

What hormones are associated with the pars nervosa?

thyroid gland

Endocrine organ derived from developing endoderm of the foramen cecum of the tongue, highly vascular, butterfly-shaped, and anterior to the trachea.

developing endoderm of the foramen cecum

From what embryologic tissue/location is the thyroid gland derived?

anterior to the trachea

Where is the thyroid gland located relative to the trachea?

inferior thyroid artery and veins

Which vessels are specifically listed as supplying/draining the thyroid gland?

TRH → TSH → thyroid hormone

What is the basic stimulatory pathway of the thyroid feedback loop?

TRH

What hormone is released by the hypothalamus and acts on the anterior pituitary in the thyroid feedback loop?

TSH

What hormone is released by anterior-pituitary thyrotropic cells in response to TRH?

follicular cells

Which thyroid cells are stimulated by TSH to release thyroid hormone?

negative feedback

Increased thyroid hormone/body temperature inhibits hypothalamic TRH and pituitary TSH by what type of regulation?

thyroid follicles

What structures in the thyroid contain colloid and are associated with thyroid hormone production?

follicular cells

Which cells line thyroid follicles and produce thyroid hormones?

colloid

What material fills the thyroid follicles?

T3 and T4

What thyroid hormones are associated with the colloid in this lecture?

increase metabolic rate; influence body growth and development

What are the major functions of T3 and T4 listed in the lecture?

Graves disease

What condition is hyperthyroidism caused by excessive thyroid hormone secretion from follicular cells?

Hashimoto thyroiditis

What condition is hypothyroidism caused by abnormally low thyroid hormone production?

parafollicular cells / C cells

Which thyroid cells secrete calcitonin?

calcitonin

What hormone is secreted by parafollicular / C cells?

calcitonin

Which hormone inhibits osteoclast bone resorption and decreases blood calcium?

decreases blood calcium

What effect does calcitonin have on blood calcium levels?

synthesis and secretion of thyroglobulin

What is step 1 of thyroid hormone synthesis?

uptake and concentration of iodide from blood and release into colloid

What is step 2 of thyroid hormone synthesis?

iodination of thyroglobulin in the colloid

What is step 3 of thyroid hormone synthesis?

formation of T3 and T4

What is step 4 of thyroid hormone synthesis?

resorption of colloid by endocytosis

What is step 5 of thyroid hormone synthesis?

release of T3 and T4 from the cell into circulation

What is step 6 of thyroid hormone synthesis?

thyroglobulin synthesis → iodide uptake → iodination → T3/T4 formation → colloid resorption → T3/T4 release

Put the six steps of thyroid hormone synthesis in order.

Hashimoto thyroiditis

Which thyroid disease causes enlargement of the thyroid, hypothyroidism, cold sensitivity, pale skin, muscle pain, and weight gain?

Hurthle cells

What cells with abundant eosinophilic cytoplasm are associated with Hashimoto thyroiditis?

parathyroid gland

Which endocrine organ contains chief cells and oxyphil cells?

chief cells and oxyphil cells

What two cell types are emphasized in the parathyroid gland?

PTH / parathormone

What hormone is associated with the parathyroid gland?

chief cells

Which parathyroid cells produce PTH?

PTH

Which hormone increases osteoclast activity and increases blood calcium?

increases blood calcium

What effect does PTH have on blood calcium levels?

superior, middle, and inferior suprarenal arteries

What three arterial sources supply the adrenal glands?

mesoderm

From what embryologic tissue is the adrenal cortex derived?

neural crest

From what embryologic tissue is the adrenal medulla derived?

capsule → zona glomerulosa → zona fasciculata → zona reticularis → medulla

List the adrenal gland layers from superficial to deep.

zona glomerulosa

What is the outermost zone of the adrenal cortex?

zona fasciculata

What is the middle zone of the adrenal cortex?

zona reticularis

What is the innermost zone of the adrenal cortex?

zona glomerulosa; aldosterone

Which adrenal cortical zone produces mineralocorticoids, especially aldosterone?

zona fasciculata; cortisol and corticosterone

Which adrenal cortical zone produces glucocorticoids?

zona reticularis; dehydroepiandrosterone (DHEA)

Which adrenal cortical zone produces androgens?