Term
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Definition
| deposite product (hormones) directly into the bloodstream |
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Term
Composed of glands 5 total |
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Definition
1. Adrenal 2. Thyroid 3. Parathyroid 4. Pituitary 5. Pineal |
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Definition
-paired -assymetrical -at superior poles of kidney -inner medulla & outer cortex -surrounded by dense fiberous connective tissue -richly vascularized -arterial branch --> subcapsular plexus --> cortical & medullary capillary bed -vessels of cortex drains into medullary capillaries (therefore, medullary capillaries have two blood supplies) arterial blood via medullary venous blood via cortical
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Definition
-from mesoderm -produces corticosteroids from cholesterol -secretion regulated by adrenocorticotropic hormone (ACTH) from anterior pituitary -regulated via negative feedback -high levels of secreted compounds inhibits anterior pituitary from releasing more ACTH **release products into bloodstream upon stimulation do NOT store them in secretory granules |
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Term
| Layers of the Adrenal Cortex |
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Definition
1. zona glomerulosa (ZG) 2. zona fasciculata (ZF) 3. zona reticularis (ZR) |
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Term
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Definition
-outermost layer -made of cords and clusters of small columnar cells -may contain lipid droplets -produce mineralocorticoid (aldosterone) -stimulated by a. angiotensin II b. ACTH c. increase in serum K+ concentration |
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Definition
-influences distal convoluted tubule -maintains water balance via Na reabsorption and K secretion -other targets a. gastric mucosa b. salivary sweat glands c. sweat glands -results in a. increased blood volume b. elevated blood pressure |
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Definition
-middle layer -largest percent volume of entire gland (65-80%) -elongated cords of large polyhedral cells (1-2 thick) -bordered by blood vessels -cytoplasm may contain lipid droplets may appear vacuolated (spongiocytes) -stimulated by a. ACTH b. ZF -produces gucocorticoids (cortisol and corticosterone)
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Term
| Cortisol and Corticosterone |
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Definition
-role in anabolic (uptake of substances for glucose and glycogen synthesis) -role in catabolic (lipolysis and proteolysis) -help withstand stress -anti-inflammatory role -assist in immune suppression |
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Definition
-innermost layer -smallest percent of volume of gland (7%) -irregular, anastomosing cords with darkly-staining cells -cells compared to cells in the ZF a. smaller b. fewer lipid droplets c. may contain sig amounts of lipofuscin pigment -stimulated by ACTH -produces a. androgens (dehydroepiandosterone and androstenedione)
b. small amounts of glucocorticoids |
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Term
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Definition
-from neural crest (ectoderm) -center of adrenal gland -consists of cords and clusters of polyhedral cells -contain cytoplasmic secretory granules -also called chromaffin cells -modified postganglionic secretory neurons -acts as modified sympathetic ganglion -ganglionic (non-secretory) nerve cells scattered throughout -stimulated by preganglionic sympathetic splanchnic neurons -secrete (catacholamines)
a. epinephrine b. norepinephrine |
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Definition
-INCREASES a. heart rate b. cardiac output c. blood flow through organs d. blood glucose e. gluconeogenesis f. oxygen consumption g. pituitary ACTH secretion (associated with physiological source like pain) |
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Definition
Causes vasoconstriction of the peripheral bloos vessels = elevated blood pressure (often associated with an emotional source) |
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Definition
-endodermally-derived -role in stimulation of metabolism via synthesis of a. Thyroxin (T4) b. Triiodothyronine (T3)
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Definition
-numerous round oval follicles -rich network of vascular + neural elements -embedded in stroma -surround each follicle -composed of reticular fibers -capsule of loose connective tissue surrounds entire thyroid gland -within the thyroid follicles is colloid -homogeneous -eosiniphillic -contains T3 and T4 bound to thyroglobulin |
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Term
| Follicular Cells of Thyroid |
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Definition
-nuclei -round to oval -center of cell -contain 1-2 nucleoli -numerous short villous extensions go into colloid -when thyroid hormone is in demand a. follicular cell extends pseudopods into colloid b. brings thyroid hormone into the cell |
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Term
| Parafollicular (C) cells of Thyroid |
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Definition
-neuroendocrine cell -found between thyroid follicles -secrete calcitonin -promotes decrease in serum calcium because it
-inhibits actions of osteoclasts therefore -promotes osteogenesis |
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Term
| Synthesis of Thyroid Hormones |
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Definition
-requires iodie (I) -regulated by thyroid stimulating hormone (TSH) -from anterior pituitary |
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Term
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Definition
-synthesized and packaged in RER and Golgi (of follicular cell) -released through apical membrane into colloid (stored in lumen of thyroid follicle) |
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Definition
-active transported into follicular cell via iodide pump -oxidized into cytoplasm by thyroid peroxidase -then moves into colloid where it iodinates tyrosine residues of thyroglonulin -this forms monoiodinated tyrosine (MIT) and diiodinated tyrosine (DIT) -MIT + DIT = T3 -DIT + DIT = T4 |
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Term
| Release of Thyroid Hormones |
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Definition
-TSH released form basophils of anterior pituitary -binds to basilar cell membrane of follicular cell -initaties formation of cytoplasmic extensions of apical cell membrane which encloses some colloid for endocytosis -endocytic vesicle fuses with lysosome -lysosomal proteases cleave iodinated residues from thyroglobulin molecule, release MIT, DIT, T3, T4 -T3 and T4 cross cell membrane into capillaries -MIT and DIT broken down into iodine and tyrosine -remain in cytoplasm to be recycled
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Term
| Functions of Thyroid Hormones |
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Definition
-T3 is more biologically active (bound less strongly) Thyroid Hormones: -increase carb metabolism -fatty acid synthesis -vitamin uptake =overall increase in cellular metabolism -decrease cholesterol synthesis -decrease phospholipid synthesis -decrease triglyceride synthesis |
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Term
| Elevated Levels of Thyroid Hormone |
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Definition
-decreased body weight -increased -heart rate -metabolism -respiration -muscle function |
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| Elevated Levels of Thyroid Hormone in Children |
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Definition
-increased growth rate -facilitates mental processes -stimulates endocrine secretion |
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Definition
-four encapsulated glands located at each pole of thyroid -embryonically derived from third (inferior) and fourth (superior) pharyngeal pouches |
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Definition
-parenchyma composed of two types of cells 1. chief cells 2. oxyphil cells
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Definition
-most numerous -small -slightly eosinophilic -ovoid and vesicular nucleus -small cytoplasmic secretory granules contain parathyroid hormone (PT)
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Definition
-occur singly or in clusters -larger -more eosinophilic -abundent mitochondria -may be an inactive phase of chief cells |
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Definition
With age the parenchyma is gradually replaced by adipose tissue which will eventually constitute 50% of the cell. |
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Definition
-regulation of serum calcium levels via PTH -PTH -increases serum calcium concentration -decreases serum phosphate concentration -acts on -bone -kidney -intestine
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Definition
-PTH binds to osteoblasts -induces them to produce osteoclast stimulating facto therefore increasing osteoclast activity + # -leads to bone resorption -leads to calcium liberation in bloodstream
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Definition
-PTH acts on celss of renal tubules to resorb calcium -prevents resorption of phos[hate -thus, reduces serum phosphate concentration -increases serum calcium concentration |
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Definition
-stimulates production of active form of Vitamin D in kidneys -casues calcium to be absorped by intestinal epitelial cells |
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Definition
-operates on negative feedback loop -both PTH and calcitonin serve to maintain calcium homeostasis |
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Term
| Pituitary Gland (hypophysis) |
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Definition
-lies in recession of spenoid bone called sella turcica -connected to hybpthalmus by hypophyseal stalk -derived embryologically from neural + oral ectoderm -produces and stores hormones that regulate -growth -metabolism -reproduction -has 2 major anatomical subdivisons 1. Adenohypophysis (anterior pituitary) 2. Neurohypophysis (posterior pituitary) |
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Term
Adenohypophysis (anterior pituitary) |
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Definition
-from invagination of oral ectoder known as Rathke's pouch -further divided into: anterior lobe (pars distalis) pars tuberalis pars intermedia
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Term
| Neurohypophysis (posterior pituitary) |
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Definition
-derived from neural ectoderm in the form of extensions of diencephalon -comprised of -pars nervosa -infundubulum (neural stalk) (remnants of Rathke's pouch are found between the two lobes) |
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Term
| Blood Supply of Pituitary Gland |
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Definition
-richly vascularized -blood supply conveyed mainly by superior hypohyseal arteries which divide into a
-primary capillary plexus to supply -median eminence and -infundibulum -median eminence + infundibulum form portal venous system prior to entering secondary capillary plexus in adenohyophysis (anterior) -this consistutes hypophyseal portal system
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Term
| Hypophyseal Portal System |
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Definition
-responsible for transporting neurosecretory hormones form hypothalmus to anterior pituitary -these hormones modulate secretion of anterior pituitary hormones |
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Term
| Structure and Function of Andenohypophysis |
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Definition
-enclosed in fberous capsule -contains cords of cells supported by reticulin fibers -numerous intervening fenestrated capillaries Further divided into: pars distalis pars tuberalis pars intermedia
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Term
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Definition
-composed of populations of: 1. chromophil cells 2. chromphobe cells
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Term
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Definition
can be either: -acidophils -basophils |
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Definition
-most common -has 2 subtypes 1. somatotrophs 2. mammotrophs
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Term
| Chromophils - Acidophils - Somatotrophs |
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Definition
-secrete growth hormone (GH) -increases cellular metabolic rate -increases growth of long bones by inducing hepatocytes to produce insulin-like growth factor causing epiphyseal plate chondrocytes to divide Releasing Hormone: somatotropin releasing hormone (SRH) Inhibiting Hormone: somatostatin
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Term
| Chromophils - Acidophils - Mammotrophs |
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Definition
-secrete prolactin -encourages development of mammary glands during pregnancy and milk secretion Releasing Hormone: thyrotropin releasing hormone (TRH) oxytocyn
Inhibiting Hormone: prolactin inhibiting hormone (PIH) dopamine (from CNS)
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Term
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Definition
-usually found at periphery of pars distalis -3 subtypes 1. corticotrophs 2. thyrotrophs 3. gonadotrophs |
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Term
| Chromophils - Basophils - Corticotrophs |
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Definition
-secrete adrenocorticotropic hormone (ACTH) -stimulates release of hormones by adrenal cortex Releasing Hormone: corticotropin releasing hormone (CRH)
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Term
| Chromophils - Basophils - Thyrotrophs |
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Definition
-secrete thyroid stimulating hormone (TSH) Releasing Hormone: thyrotropin releasing hormone (TRH) Inhibiting Hormone: presence of serume T3 and T4
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Term
| Chromophils - Basophils - Gonadotrophs |
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Definition
-secrete FSH and LH -Females: FSH stimulates secondary ovarian follicle devlopments and estrogen secretion LH promotes follicle maturation and progesterone + estrogen secretion -Males: FSH stimulates spermatogenesis LH induces testosterone production by testicular intestital cells Releasing Hormone: gonadotropin (GnRH) Inhibiting Hormone: serum estrogen, progesterone, and testosterone
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Term
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Definition
-named for inability to take H & E stains -probably degranulated chromophils |
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Definition
-majority of secretory cells are gonadotrophs
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Definition
-contain colloid-filled cysts lined by cuboidasl cells -remenants of Rathke's pouch -secrete alpha-melanocyte stimulating hormone (α-MSH)
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Term
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Definition
-consists of unmyelinated axons -carry neurosecretory granules from cell bodies in supraoptic and paraventricular nuclei to pars nervosa (released into circulation) -granules can accumulate and cause distention of axon forming pale basophilic HERRING BODIES -axons bordered by pituictye (glial cell) |
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Term
Neurohypophysis Hormone Secretion (2) |
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Definition
-2 types -each is bound to ots own type of carrier protein called neurophysin 1. antidiuretic hormone (ADH) (vasopressin) 2. oxytocin
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Term
Neurohypophysis Hormone Secretion Antidiuretic Hormone (ADH) (vasopressin) |
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Definition
-targets cells of renal collecting tubules -increases water permiability -thus forming low volume of concentrated urine -mainly produced in supraoptic nuclei
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Term
Neurohypophysis Hormone Secretion Oxytocin |
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Definition
-causes smooth muscle contraction of uterine myometrium during childbirth -causes myoepithelial contraction in mammary glands which assist in milk ejection -mainly produced in paraventricular nuclei |
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Definition
-small conical structure -projects from roof of diencephalon -covered by pia mater -function is goverend by circadian rhythms -has concentric basophilic calcifications called Corpora Arenacea
-2 major cell types 1. pinealoytes 2. astrocyte |
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Term
| Pineal Gland - Pinealocytes |
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Definition
-slighlt basophilic -irregular nuclei -cellular processes contact regional capillaries and sometimes neighboring pinealocytes -secrete melatonin -secreted in dark hours -regulates activity of gonads and possibly other organs
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Term
| Pineal Gland - Astrocytes |
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Definition
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Term
| Innervation of Pineal Gland |
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Definition
-through parasympathetic nerves from superior cervical ganglion -unmyelinated axons terminate on pinealocytes release: norepinephrine = stimulate melatonin secretion
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