Term
| Where is the pituitary gland located? |
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Definition
| In a cavity of the sphenoid bone |
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Term
| From what embryologic structure does the pituitary gland develop from? |
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Definition
| Oral ectoderm (Rathke's pouch) and floor of diencephalon |
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Term
| What are the derivatives of oral ectoderm? |
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Definition
Adenohypophysis = Anterior pituitary
- Pars distalis (anterior pituitary)
- Pars tuberalis (surrounds neural stalk)
- Pars intermedia (vestigial) |
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Term
| What are the derivatives of diencephalon? |
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Definition
Neuropophysis = Posterior pituitary
- Neural stalk including stem and median eminence
- Pars nervosa (posterior pituitary)
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Term
| The superior and inferior hypophysial arteries are branches off of what? |
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Definition
| Internal carotid arteries |
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Term
| What is the function of the primary capillary plexus? Where is it located? What is it derived from? |
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Definition
The function is to absorb and deliver inhibiting/releasing hormones to the pars distalis
It is located in the median eminence
It is derived from the superior hypophysial arteries |
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Term
| Where do the long portal veins leave from and where do they go? |
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Definition
| The long portal veins leave the primary capillary plexus and descend down the pituitary stalk to the pars distalis of the anterior pituitary |
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Term
| What do the long portal veins give rise to? |
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Definition
| A secondary capillary plexus within the anterior pituitary |
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Term
| Hormones synthesized in the pars distalis enter the general circulation via what structure? |
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Definition
| The secondary capillary plexus |
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Term
| The capillary plexus within the pars nervosa (posterior pituitary) carries products from which structures into the general circulation? |
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Definition
| The supraoptic and paraventricular nuclei |
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Term
| Where are peptides synthesized by the secretory neurons in the supraoptic and paraventricular nuclei transported to? |
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Definition
| The neurohypophysis (posterior pituitary) |
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Term
| Where are peptides synthesized by neurons in the hypothalamus (dorsal-medial, ventral-medial, and infundibular nuclei) released and transported to? |
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Definition
| They are released in the median eminence and transported to the anterior pituitary via a capillary portal system |
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Term
| What are the defining features of the pars distalis? |
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Definition
| Cords of glandular cells surrounded by capillaries; Chromophobes and chromophils (acidophils and basophils); hormones include somatotrophin (GH), prolactin, FSH, LH, MSH, TSH, and ACTH |
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Term
| What are the features of the pars intermedia? |
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Definition
| Rudimentary region in humans; weakly basophilic cells |
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Term
| What are the features of the pars tuberalis? |
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Definition
| Cells arranged in cords along blood vessels (surrounds the neural stalk); most of these cells secrete FSH or LH |
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Term
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Definition
Storage granules within the pars nervosa which store hormones synthesized by neurons of the supraoptic and paraventricular nuclei
Stored hormones are usually bound to the carrier protein neurophysin |
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Term
| What are the characteristics of the neurohypophysis? |
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Definition
| Axons of hypothalamic neurons (from supraoptic and paraventricular nuclei); 25% of volume of neurohypophysis is pituicytes (highly branched glial cells); Herring bodies are present in dilated axon terminals |
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Term
| What are the neurons of the neurohypophysis (posterior pituitary)? |
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Definition
Oxytocin and vasopressin (arginine vasopressin / antidiuretic hormone); neurophysin is the binding protein for each
Released from storage via neuronal impulses from the hypothalamus |
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Term
| What causes diabetes insipidus? |
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Definition
| Antidiuretic hormone deficiency, which causes polyuria |
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Term
| What 2 sources are the adrenal glands derived from during development? |
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Definition
| Coelomic epithelium and neural crest |
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Term
| What regulates the metabolic activity of the adrenal cortex? |
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Definition
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Term
| What regulates the metabolic and secretory activity of the adrenal medulla? |
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Definition
| Preganglionic sympathetic nerve fibers |
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Term
| How does blood drain from the adrenal glands? |
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Definition
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Term
| What are the three groups of adrenal gland arteries and what are their functions? |
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Definition
Capsular arteries - provide an extensive subcapsular network
Cortical arteries - irrigate the cortex
Medullary arteries - pass through the cortex directly to the medulla
Cortical and medullary arterioles originate as branches of capsular arteries |
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Term
| What are the two sources of blood for the medullary capillary bed? |
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Definition
| Cortical veins and medullary arterioles |
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Term
| What is the typical structure of the cells of the adrenal cortex? |
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Definition
| Foam cells with lipid droplets |
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Term
| What are the three concentric zones of the adrenal cortex and what are their functions? |
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Definition
Zona glomerulosa - aldosterone (salt)
Zona fasiculata - cortisol (sugar)
Zona reticularis - sex hormones (sex, duh) |
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Term
| What are the neural crest derived cells of the adrenal medulla called? |
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Definition
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Term
| What is the structure of the adrenal medulla? |
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Definition
| Polyhedral cells in cords with a surrounding network of capillaries |
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Term
| Where are lipofuchsin granules present? |
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Definition
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Term
| What are the islet of langerhans cell types and what do they secrete? |
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Definition
A cells - glucagon
B cells - insulin
D cells - somatostatin
F cells - pancreatic polypeptide |
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Term
| Where is the thyroid gland located? |
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Definition
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Term
| What is the thyroid gland derived from during development? |
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Definition
| Endoderm of the primitive gut |
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Term
| What are the characteristics of the thyroid gland? |
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Definition
Loose CT capsule with septae
Highly vascular organ
Fenestrated capillaries
Follicles (simple epithelium with variable morphology)
Colloid
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Term
| What are the effects of TSH on the Thyroid? |
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Definition
| Stimulates thyroid hormone synthesis; increase height of follicular epithelium; decreases quantity of colloid as well as follicle diameter |
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Term
| In a hypoactive thyroid, the most common epithelium is what? |
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Definition
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Term
| Would a thyroid with high metabolic activity have a larger or smaller diameter? |
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Definition
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Term
| What are the characteristics of C cells (Parafollicular cells )? |
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Definition
May form part of the follicular epithelium or may exist as isolated clusters between follicles; Larger and less intensely stained compared to follicular cells; Arise from neural crest cells
Synthesize and secrete calcitonin; secretion of calcitonin stimulated by increased levels of blood calcium |
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Term
| How many parathyroid glands are there usually and where are they located? |
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Definition
| There are typically 4 parathyroid glands and they are located behind the thyroid gland at each upper and lower pole |
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Term
| Where are the parathyroid glands derived from embryologically? |
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Definition
| 3rd and 4th pharyngeal pouches |
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Term
| What are the two types of parathyroid parenchymal cells? |
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Definition
Chief cells and oxyphil cells
Chief cells secrete parathyroid hormone in response to hypocalcemia |
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Term
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Definition
Larger polygonal cells
Smaller population than chief cells
Unknown function |
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Term
| How does increasing age affect the parathyroid gland? |
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Definition
| Adipose tissue replaces secretory cells |
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Term
| What are the functions of parathyroid hormone? |
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Definition
| Increases blood calcium levels (acts on osteoclasts), reduces blood phosphate levels (acts on kidneys), and promotes increased calcium absorption from the gut |
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