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38 Cards in this Set
- Front
- Back
- 3rd side (hint)
QUESTION What are three characteristics of endocrine glands?
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ANSWER
1) No ducts 2)Deposit hormones directly into bloodstream 3) Richly vascularized |
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QUESTION What is the dual blood supply of the adrenal medulla?
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ANSWER
Arterial blood via the medullary arteries, and venuous blood via the cortical arteries. |
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QUESTION
What is the blood supply of the adrenal glands? |
ANSWER
Arterial branches--> subcapsular plexus--> adrenal capsule--> cortical + medullary capillary beds |
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QUESTION
What are the three layers of the adrenal cortex (outermost to innermost)? |
ANSWER
1)Zona glomerulosa 2)Zona fasciculata 3)Zona reticularis |
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QUESTION
Characteristics of the zona glomerulosa |
ANSWER
Outermost layer of cortex, comprised of cords and clusters of columnar cells which produce mineralocorticoid hormones (mainly aldosterone) when stimulated by angiotensin II or ACTH. |
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QUESTION
Characteristics of zona fasciculata |
ANSWER
Middle layer of adrenal cortex, large polyhedral cells which produce glucocorticoid hormones (cortisol and corticosterone) when stimulated by ACTH. Largest part of adrenal gland. |
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QUESTIONS
What do cortisol and corticosterone do? |
ANSWER
-Anabolic and catabolic processes -Help organism withstand stress -Anti-inflammatory -Immune supression |
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QUESTION
Characteristics of zona reticularis |
ANSWER
Innermost layer of adrenal cortex, irregular darkly staining cells that produce androgens and small amounts of glucorticoids when stimulated by ACTH. Cells also contain lipofuscin pigment. |
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QUESTION
True or False: Cells of the adrenal cortex store their products in secretory granules |
ANSWER
False, cells of the adrenal cortex release their products into the bloodstream upon stimulation |
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QUESTION
What is the main cell of the adrenal medulla, and what does it secrete? |
ANSWER
Chromaffin cells (modified postganglionic secretory neurons) which secrete epinephrine and norepinephrine upon sympathetic stimulation |
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QUESTION
What is the role of the thyroid gland? |
ANSWER
The thyroid gland plays a role in the stimulation of metabolism through the synthesis of thyroxine (T4) and triiodothyronine (T3) |
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QUESTION
What is the most abused non-narcotic drug by physicians? |
ANSWER
Sinthroid (speeds up metabolism, keeps you up) |
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QUESTION
What is colloid and what does it contain? |
ANSWER
Eosinophilic substance within the thyroid follicles, contains T3 and T4 bound to thyroglobulin. |
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QUESTION
How does a follicular cell of the thyroid obtain thyroid hormone? |
ANSWER
When thyroid hormone is in demand, the follicular cell extends pseudopods into the surrounding colloid and brings the colloid into the cell. |
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QUESTION
What are parafollicular (C) cells? |
ANSWER
Found between thyroid follicles, larger and paler than follicular cells, secrete CALCITONIN |
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QUESTION
Describe the synthesis of thyroid hormones |
ANSWER
-Requires iodide and is regulated by TSH from the ant. pituitary - Iodide is actively transported into follicular cell, where thyroid peroxidase in the cytoplasm oxidizes it. - Oxidized iodide moves back into the colloid where it iodinates the tyrosine residues of thyroglobulin. - Forms MIT and DIT - MIT +DIT = T3 - DIT + DIT = T4 |
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QUESTION
Describe the release of thyroid hormones |
ANSWER
TSH--> basolateral membrane of follicular cell--> cytoplasmic extensions of apical membrane bring in some colloid (endocytosis)-->lysosome in FC breaks down components of colloid into MIT, DIT, T3, T4 --> T3 and T4 leave cell, MIT + DIT are broken down into iodine and tyrosine and recycled |
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QUESTION
What are the functions of thyroid hormones? |
ANSWER
Thyroid hormones, in general, increase carbohydrate metabolism, fatty acid synthesis and vitamin uptake. They DECREASE cholesterol, phospholipid, and triglyceride synthesis. |
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QUESTION
Describe the 2 cells found in the parathyroid glands, and what happens with age |
ANSWER
1)Chief cells: most numerous, cytoplasmic granules contain PTH 2)Oxyphil cells: larger than chief cells, with abundant mitochondria, unknown function 3) With age, parenchyma is gradually replaced by adipose tissue. |
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QUESTION
What is the function of the parathyroid glands? |
ANSWER
Regulation of serum calcium levels through the actions of PTH |
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QUESTION
How does PTH act on bone and kidneys? |
ANSWER
In bone: PTH stimulates osteoclast activity and number. In kidneys: PTH makes cells of renal tubule resorb calcium and prevent resorption of phosphate. Also, PTH induces production of the active form of vitamin D, which enhances calcium reapsorbtion in intestine. |
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QUESTION
What are the characteristics of the pituitary gland? |
ANSWER:
-Derived from both neural and oral ectoderm -Produces and stores hormones for growth, metabolism, and reproduction -Divided into anterior and posterior pituitary |
pituary makes hormones from two different cells:
B-FLAT: basophils make FSH, LH, ACTH, and TSH GPA: acidophils make prolactin, and growth hormone |
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QUESTION
What are the 3 sections of the anterior pituitary (aka adenohypophysis) and what layer is it derived from? |
ANSWER
1) Anterior lobe (pars distalis) 2) Pars tuberalis 3) Pars intermedia Anterior pituitary is derived from oral ectoderm (Rathke's pouch) |
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QUESTION
What are the two components of the posterior pituitary and what layer is it derived from? |
ANSWER:
Composed of pars nervosa and the infundibulum (neural stalk), derived from neural ectoderm) |
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QUESTION
What is the hypophyseal portal system? |
ANSWER:
Portal venous system is the only connection between the anterior and posterior pituitary. Portal system transports neurosecretory hormones from the hypothalamus -->ant. pituitary, where they modulate secretion of ant. pituitary hormones. |
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QUESTION
What are somatotrophs? What releases and inhibits them? |
ANSWER
Acidophilic chromophil from the pars distalis, secretes GROWTH HORMONE, which increases metabolic rate and the growth of long bones. Releasing hormone: SRH Inhibiting hormone: Somatostatin |
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QUESTION
Characteristics of mammotrophs |
ANSWER
Type of acidophilic chromophil from the pars distalis, secrete PROLACTIN, which is for development of mammary glands during pregnancy + milk secretion. Releasing hormone: PRH Inhib. hormone: PIH |
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QUESTION
Characteristics of corticotrophs |
ANSWER
Basophilic chromophil from pars distalis, secrete ACTH which stimulates release of hormones from adrenal cortex Releasing hormone: CRH |
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QUESTION
Characteristics of thyrotrophs |
ANSWER
Basophilic chromophil in pars distalis, secrete TSH Releasing hormone: TRH (thyrotropin releasing hormone) Inhib. hormone: presence of serum T3 and T4 |
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QUESTION
Characteristics of gonadotrophs |
ANSWER
Basophilic chromophil in pars distalis. Secrete follicle stimulating hormone (FSH) and leutinizing hormone (LH) Releasing hormone: GnRH Inhib. hormone: serum estrogen, progesterone, and testosterone |
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QUESTION
How do basophil hormones differ from acidophil hormones? |
ANSWER
Basophils differ from acidophils in that they have no specific inhibiting hormones (instead, basophils are inhibited by neg. feedback-- presence of substance released from target organs) |
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QUESTION
What is the most common secretory cell type in the pars tuberalis of the ant. pituitary? |
ANSWER
Gonadotrophs |
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QUESTION
What is secreted by the cells of the pars intermedia? |
ANSWER
Melanocyte stimulating hormone(MSH) |
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QUESTION
What are Herring bodies? |
ANSWER
Neurosecretory granules accumulate in the pars nervosa and cause distension of the axon, forming pale basophilic Herring bodies. |
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QUESTION
What is a pituicyte? |
ANSWER
Glial cell bordering the axon in the pars nervosa (posterior pituitary) |
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QUESTION
What are the two hormones secreted from the posterior pituitary? |
ANSWER
1)ADH- increases water permeability in renal collecting tubules, concentrating urine. 2)Oxytocin: causes smooth muscle contraction in childbirth, and mammary gland milk ejection |
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QUESTION
What governs the function of the pineal gland? |
ANSWER
Circadian rhythms |
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QUESTION
What are 3 things found in the pineal gland? |
ANSWER
1)Pinealocytes which secrete melatonin and seratonin 2)Astrocyte-like interstitial cells 3) Corpora arenacea: concentric basophilic calcifications |
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