Term
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Definition
| Potent chemical signaling substances that are produced by secretory cells and released into the circulatory sustem |
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Term
| What are on target cells that cause them to be affected by hormones? |
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Definition
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Term
| What are the three mechanisms of chemical signaling that are based on distance? |
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Definition
Endocrine
Paracrine
Autocrine |
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Term
| Which secretory cells are most linked to the hypothalamo-hypophyseal (neuroendocrine) system via feedback loops? |
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Definition
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Term
| Where does the Pituitary gland reside? |
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Definition
| In a cavity in the sphenoid bone (sella turcica). |
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Term
| Explain the embryological development of the Pituitary Gland.[image] |
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Definition
It develops from the oral ectoderm (Rathke's pouch) and the diencephalon
[image] |
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Term
| Which portion of the Pituitary is associated as the Adenohypophysis? |
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Definition
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Term
| What are the Derivatives of the Oral Ectoderm? |
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Definition
Pars Distalis (Anterior Pituitary)
Pars Tuberalis (Surrounds Neural Stalk)
Pars Intermedia (Vestigial) |
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Term
| What are the derivatives of the Diencephalon? |
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Definition
Neural Stalk (Infundibulum)
Pars Nervosa (Posterior Pituitary) |
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Term
| The superior and inferior hypophysial arteries arise from which artery? |
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Definition
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Term
| What is the Primary Capillary Plexus? |
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Definition
| In the median eminence (derived from the superior hypophysial arteries) and serves to absorb and deliver inhibiting/releasing hormones to the pars distalis. |
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Term
| What do Long Portal Veins ultimately give rise to in the anterior pituitary? |
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Definition
| The seconday capillary plexus |
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Term
| How do hormones synthesized in the pars distalis enter the general circulation? |
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Definition
| They enter via the secondary capillary plexus. |
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Term
| Plexus within the pars nervosa (posterior pituitary) carries products of ________ and _________ nuclei to the general circulation. |
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Definition
| supraoptic, paraventricular |
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Term
| What are the 3 sites for production of polypeptide, neuroendocrine hormones? |
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Definition
1. Supraoptic and Paraventricular Nuclei (Transported along axons to the neurohypophysis)
2. Hypothalamus (Released in the Median Eminence and transported to the anterior pituitary via capillary portal system)
3. Pars Distalis |
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Term
| What are MA characteristics of the Pars Distalis? |
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Definition
1. Cords of glandular cells surrounded by capillaries
2. Chromophobes and Chromophils (Acidophils & Basophils)
3. Hormones include: Somatotrophin (GH), Prolactin, FSH, LH, MSH, TSH, ACTH |
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Term
| What are MA characteristics of the Pars Intermedia? |
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Definition
1. Rudimentary region in humans
2. Weakly basophilic cells |
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Term
| What are MA characteristics of Pars Tuberalis? |
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Definition
1. Cells arranged in cords along blood vessels - surrounds the neural stalk
2. Most of these cells secrete FSH or LH |
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Term
| Hormones that are produced from the supraoptic and paraventricular nuclei are released from which portion of the pituitary? |
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Definition
|
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Term
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Definition
| These are storage granules within the pars nervosa associated with hormones synthesized from the paraventricular and supraoptic neurons. |
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Term
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Definition
| A carrier protein associated with Herring Bodies. |
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Term
| What comprises of 25% of the volume of the neurohypophysis? |
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Definition
| Pituicytes, which are highly branched glial cells |
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Term
1. What are the hormones of the Neurohypoohysis?
2. How are they released from storage? |
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Definition
1. Oxytocin, Vasopressin
2. Via neuronal impulses from the hypothalamus
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Term
| Where are the adrenal glands located? |
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Definition
| At the superior poles of the kidneys |
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Term
| What are the 2 sources that the adrenal glands derive from embryologically? |
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Definition
| Coelomic Epithelium and Neural Crest |
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Term
1. What regulates the metabolic activity of the adrenal cortex?
2. What regulates the metabolic and secretory activity of the adrenal medulla? |
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Definition
1. ACTH, from the anterior pituitary
2. Preganglionic Sympathetic Nerve Fibers |
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Term
| What are hormonal targets for epinephrine and norepinephrine? |
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Definition
| Glandular Epithelial Cells, Cardiac Cells, Smooth Muscle of Blood Cells and Viscera |
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Term
| What are the three groups of adrenal arteries? |
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Definition
Capsular Arteries - Provide extensive subcapsular network
Cortical Arteries - Irrigate the Cortex
Medullary Arteries - Pass through the cortex to the medulla |
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Term
| Cortical and medullary arteries originate as branches of __________ arteries. |
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Definition
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Term
| Capillaries of the cortical and medullary arterioles form a single _________. |
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Definition
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Term
| What are the 3 concentric zones in the Adrenal Cortex and what are their physiological functions? |
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Definition
Zona Glomerulosa (Salt - Aldosterone)
Zona Fasiculata (Sugar - Cortisol)
Zona Reticularis (Sex Hormones) |
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Term
| What are the characteristics of the Zona Glomerulosa? |
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Definition
1. Thin outer zone adjacent to the capsule
2. Small columnar or pyramidal cells arranged in clusters
3. Continuous with cords of cells in subjacent region |
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Term
| What are the characteristics of the Zona Fasculata? |
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Definition
1. Large polyhedral cells arranged in parallel columns with lipid droplets.
2. Columns of spongyocytes separated by cortical sinusoids |
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Term
| What are characteristics of the Zona Reticularis? |
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Definition
1. Innermost layer of cortex
2. Lipofuchsin granules present |
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Term
| What are the MA characteristics of the Adrenal Medulla? |
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Definition
Composed of polyhedral cells in cords with a surrounding network of capillaries.
Cells of the medulla are considered to be postgangionic neurons of the sympathetic nervous system. Referred to as chromaffin cells. |
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Term
| What are the functional units of the Endocrine Pancreas? |
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Definition
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Term
| What are the MA characteristics of the Islets of Langerhans? |
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Definition
1. Spherical configuration of islets
2. Composed of rounded/polygonal cells
3. Fenestrated capillary network
4. Separated from exocrine tissue by reticular fibers
5. 10% of cells innervated by autonomic nerve fibers |
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Term
| What are the islet cells types, abundance, and function? |
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Definition
A cells - 20% - Synthesize Glucagon
B cells - 70% - Synthesize Insulin
D cells - 5% - Synthesize Somatostatin
F cells - Rare - Pancreatic Polypeptide |
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Term
| Where is the location of the thyroid gland? |
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Definition
| It is located anterior to the larynx |
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Term
| From what does the thyroid gland derive from? |
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Definition
| Derives from the endoderm of the primitive gut. |
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Term
| What hormones does the thyroid synthesize? |
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Definition
| T3 and T4, what are important from growth, differentiation, and control of metabolic rate |
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Term
| The thyroid gland is composed of ___________, that are lined by simple epithelium. |
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Definition
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Term
| What is the colloid in the thyroid gland? |
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Definition
| It is the gelatinous matrix that stores the extracellular hormone precursor, thyroglobulin. |
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Term
| What are the MA characteristics of the thyroid gland? |
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Definition
1. Loose connective tissue capsule with septae
2. Highly vascular organ
3. Fenestrated capillaries
4. Follicles
5. Colloid |
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Term
| What is the effect of TSH on the thyroid? |
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Definition
1. Stimulates thyroid hormone synthesis
2. Increases height of follicular epithelium
3. Decreases quantity of colloid as well as follicle diameter |
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Term
| T/F: Larger diameter follicles are associated with hypoactive thyroid. |
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Definition
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Term
| What are the characteristics of Smaller Diameter thyroid follicles? |
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Definition
Less Colloid
Simple Columnar Epithelium
Associated with higher metabolic activity |
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Term
| What are characteristics of Parafollicular or C-Cells? |
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Definition
1. May form as part of follicular epithelium
2. May exist as isolated clusters between follices
3. Larger and less intensely stained compared to follicular cells
4. Arise from neural crest cells |
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Term
| What is the endocrine function of Parafollicular or C-Cells? |
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Definition
| Secrete Calcitonin, which decreases blood calcium levels by inhibiting bone loss. |
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Term
| How many parathyroid glands are there and where are they located? |
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Definition
| There are 4 which are located behind the thyroid gland at each upper and lower pole. Usually found in the capsule that covers the lobes of the thyroid, but can be found embedded in the thyroid parenchyma. |
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Term
| What are the two types of parathyoid parenchyma cells? |
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Definition
| Chief Cells, Oxyphil Cells |
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Term
| What do chief cells secrete and what is its effect? |
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Definition
| Parathyroid Hormone. Works to increase blood calcium levels. |
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Term
| With increasing age, what comes to replace the secretory cells in the Parathyroid glands? |
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Definition
|
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Term
| What are the general effects of Parathyroid Hormones? |
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Definition
1. Increases blood calcium levels
2. Reduces blood phosphate levels
3. Promotes calcium absorbtion in the gut |
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