Endocrinology Set 1

Gonadotropin-inhibiting hormone (GnIH)

-releasing hormone for lutenizing hormone and follicle stimulating hormone in testes or ovaries -secreted by target testosterone and estrogen

Oocytes

A cell in an ovary that may undergo meiotic division to form an ovum.

Spermatogonium

A diploid cell that can undergo mitosis to form more spermatogonium, and can also be triggered to undergo meiosis to form sperm.

Vas Deferens

A duct that carries spermatozoa from the epididymis to the ejaculatory duct.

AVP

A fall in blood volume of greater than 8 % (hemorrhage), quiet standing (orthostatic hypotension), and positive pressure breathing, all of which reduce cardiac output and therefore central blood volume, are potent stimuli for ________release.

Blastocyst

A fluid-filled sphere formed about 5 days after fertilization of an ovum that is made up of an outer ring of cells and inner cell mass. THis is the structure that implants in the endometrium of the uterus.

Gonad

A general term for the organ that produces gametes.

Ovaries

Ablation of the ________produces a prompt increase in plasma levels of LH and FSH.

Diuresis

Abnormal secretion of large amounts of urine.

Thyrotropin-releasing hormone

Acts on the anterior pituitary gland to release thyroid-stimulating hormone (TSH) as well as prolactin (PRL).

Gonadotropins

Anterior pituitary topic hormones FSH (follicle stimulating hormone) and LH (luteinizing homeon) that stimulates the gonads (testes and ovaries) to produce gametes and to secrete sex steroids.

Streak Gonads

Complete sexual infantilism, no normal ovarian tissue present.

Osmoreceptors

Continually monitor serum osmotic pressure and when osmolarity increases, the hypothalamus stimulates thirst.

SF-1

Controls expression of enzymes involved in steroidogenesis, influences gonad and adrenal developmentm and controls production of StAR.

Angiotensin II

Converted in the lung capillaries from angiotensin I; stimulates production of alderostone in the adrenal cortex. Increases blood pressure by stimulating kidneys to reabsorb more water and by releasing aldosterone.

Atresia

Degeneration of ovarian follicles that never ovulate is termed ______.

Natriuresis

Excretion of sodium in the urine; although this is normal, this term usually applies to greater than normal sodium excretion.

Oxytocin

Extremely severe pain, increased temperature, and loud noise can inhibit release (probably via an opioid mechanism).

Cryptorchidism

Failure of one or both testes to move into the scrotum as the male fetus develops.

Ovary

Female body part that produces primarily progesterone and estradiol.

Androgen

Generic term for an agent (usually a hormone, such as testosterone and androsterone) that stimulates development of male characteristics.

Oxytocin

Hemorrhage and psychogenic stress (restraint, novel environment, mild apprehension, and fear) stimulate secretion.

Vasopressin / ADH

Hormone secreted by the posterior lobe of the pituitary gland; stimulates the kidneys to reabsorb water.

AVP

Increased partial pressure of carbon dioxide or reduced partial pressure of oxygen, pain, stress, increased temperature, β -adrenergic agents, estrogens, progesterone, opiates, barbiturates, nicotine, and prostaglandins have been demonstrated to stimulate release.

Progesterone

Inhibits FSH-induced estradiol production.

Aldosterone

Item 1

Cortisol

Item 2

Eicosanoids

Lipids that exert complex control over many bodily systems, mainly in inflammation or immunity, and as messengers in the central nervous system.

Hypothalamus

Located at the base of the brain, ventral to the thalamus.

Mullerian Duct

MIH will cause it to undergo apoptosis without MIH it will persist and differentiate.

AVP

Maneuvers that increase total blood volume (isotonic saline or blood infusion, cold water immersion) suppress _______release.

Spermatozoa

Mature spermatids that are fully functional and capable of fertilizing a human ovum.

Four phases of the menstrual cycle

Menstruation, which lasts about 4-5 days; a follicular phase of the ovary, which corresponds to the proliferative phase of the endometrium and lasts for 10-16 days; an ovulatory phase, which lasts for about 36 hours; and a luteal phase, which corresponds to the secretory phase of the endometrium.

Zona Glomerulosa

Outermost layer of Adrenal cortex. Secretes Aldosterone (mineralocorticoids)

Endothelins

Potent vasoconstrictor peptides that act locally. Stimuli for their release include Angiotensin II, epinephrine, high dose AVP, thrombins and shear stress.

Angiotensin converting enzyme (ACE)

Present on capillary endothelial cells, especially in the lungs. Converts angiotensin I into angiotensin II.

Tropoblast

Produced when blastocyst implanted in uterus, becomes placenta

AdrenoCorticoTropic Hormone (ACTH)

Released from the anterior pituitary gland to target the adrenal cortex. It stimulates the release of hormones involved in stress responses.

Follicle-stimulating hormone

Released from the anterior pituitary gland to target the ovaries & testes. In females it stimulates the development of follicles in the ovaries and in males it promotes the development of sperm cells (and stimulates the interstitial cells of the testes to produce testosterone).

AMH

Secreted by fetal Sertoli Cells to cause male sexual differentiation.

Seminiferous Tubules

Small convoluted tubules in the testes where spermatogenesis takes place.

Spermatogenesis

Sperm production; occurs in human males on a daily basis from puberty until death. Results in the production of four mature gametes (sperm) from a single precursor cell (spermatogonium). For maximum sperm viability, requires cooler temperatures and adequate testosterone.

Glucocorticoid

Steroid hormone secreted by the adrenal cortex; regulates glucose, fat, and protein metabolism.

Cortisol

Surpresses NF-kb thus resulting in an anti-inflammatory response.

Catecholamine

Sympathomimetic "fight-or-flight" hormones that are released by the adrenal glands in response to stress. They are part of the sympathetic nervous system.

Progesterone

Th e LH pulses are less frequent during the luteal phase of the menstrual cycle than during the follicular phase, presumably because of an inhibitory effect of ______________, which is secreted in large amounts by the corpus luteum.

Gonadotrophs

The adenohypophysis has a population of cells — the __________— that secretes LH and FSH. Some cells secrete only LH, others FSH, and still others secrete both hormones. Release of LH and FSH to the bloodstream is pulsatile. This is particularly noticeable in the case of LH, which has episodes of release every 70-100 minutes.

Adenohypophysis

The anterior lobe of the pituitary (of ectodermal origin)

Chromaffin Cells

The cells in the adrenal medulla that secrete epinephrine and norepinephrine.

Placenta

The main source of progesterone during pregnancy

Prostanoid

The term used to describe a subclass of eicosanoids consisting of the prostaglandins, the thromboxanes and the prostacyclins.

Decidua

Tissue that lines the uterine wall during pregnancy. The endometrium is called this once the fertilized egg is implanted into it.

SF-1, SOX9, and Wilms tumore-related 1

Transcription factors involved in gonadal development.

Ovarian Hilum

Where the ovary attaches to the mesovarium.

Inhibin B

________ may serve as a childhood serum marker for testicular activity.

external genetalia

_________ forms during the 9th -12th week fo gestation.

SOX9

transcription factor that regulates/ induces testis formation (AMH and FGF9) -induced by SRY transcription factor and Sf1, causes cell to differentiate into Sertoli cell -positive feedback mechanism to induce FGF9 and AMH -blocks B-catenin to inhibit ovary formation "universal testis-determining factor"

Four stages of lactation

(1) milk synthesis, which is initiated during the last part of pregnancy by PRL and hPL action; (2) lactogenesis, which comprises the synthesis of milk by the alveolar cells and its secretion into the alveolar lumen — it is initiated by the loss of placental steroids after birth; (3) galactopoiesis, or maintenance of established lactation, which is mainly controlled by PRL, whose release increases because of suckling by the infant; and (4) milk ejection, which is controlled by the neurohypophyseal hormone oxytocin and comprises the passage of milk from the alveolar lumen to the duct system, its collection in the ampulla and larger ducts, and its delivery to the infant.

Zona Fasciculata

(Adrenal Cortex Layers) middle-secretes glucocoticoids, primary one is cortisol.

Progestrone

-Produced primarily by the luteal cells during metestrus, diestrus, and pregnancy -Also produced by the placenta once formed -Stimulates the development of uterine glands and induces them to secrete -Renders the endometrium receptive to implantation -Promote the development of mammary glands

Prostaglandins

...

pro-opiomelanocorticotropin (POMC)

...

Two Cell Theory

..., Thecal (or leydig) cell has LH receptor and this stumulates T prod'n... diffuses across basement membrane to granulosa (sertoli) to be converted to estradiol by aromatase due to stimulation by FSH binding to receptors.

Leydig Cells

A cell that produces testosterone and other androgens and is located between the seminiferous tubules of the testes.

Epididymus

A collection of small tubules located in between the testis and vas deferens in which developed spermatozoa undergo maturation and become coated with glycoproteins.

Pituitary-Adrenal Axis

A complex set of direct influences and feedback interactions among the hypothalamus, the pituitary gland, and the adrenal glands.

AVP

A decrease in temperature, α -adrenergic agents, ethanol, and cardiac hormones can exert inhibitory actions on release.

Dihydrotestosterone

A derivative of testosterone, masculinizes the external genitals.

Spermatogonium

A diploid cell that can undergo mitosis to form more of itself, and can also be triggered to undergo meiosis to form sperm.

Prostaglandins

A group of bioactive, hormone-like chemicals derived from fatty acids that have a wide variety of biological effects including roles in inflammation, platelet aggregation, vascular smooth muscle dilation and constriction, cell growth, protection of from acid in the stomach, and many more.

Spermatid

A haploid but immature cell resulting from the second meiotic division of spermatogenesis. Spermatids undergo significant physical changes to become mature sperm (spermatozoa).

Insulin-Like Growth Factor

A hormone produced by the liver whose secretion is stimulated by growth hormone. It directly stimulates bone and cartilage growth.

Oxytocin

A hormone released by the posterior pituitary that stimulates uterine contractions during childbirth and milk ejection during breastfeeding.

Prolactin

A hormone secreted by the anterior pituitary that targets the mammary glands stimulating them to produce breast milk.

Human Chorionic Gonadotropin (hCG)

A hormone secreted by the trophoblast cells of a blasocyst (i.e. developing embryo) that prolongs the life of the corpus luteum, and thus increases the duration and amount of secreted progesterone. This helps to maintain the uterine lining so that menstruation does not occur. The presence of ________ in the blood or urine of a woman is used as a positive indicator of pregnancy.

Kisspeptin

A hypothalamic peptide hormone that increases gonadotropin secretion by facilitating the release of gonadotropin-releasing hormone.

Graafian Follicle

A large, mature, ovarian follicel with a well-developed antrum and a secondary oocyte. Ovulation of the oocyte occurs from this type of follicle.

Thecal Cells

A layer of cells surroudning the granulosa cells of the follicles in an ovary. Help produce the estrogen secreted from the follicle during the first phase of the ovarian cycle.

Menstrual Cycle

A monthly series of hormone-controlled changes that prepare the uterine lining for a pregnancy.

Atrial natriuretic peptide (ANP)

A peptide hormone secreted by cardiac atrial cells in response to atrial distension (increased blood flow); causes increased renal sodium excretion and as such lowers blood pressure (antagonizing aldosterone). Inhibits renin release. Inhibits AVP which inhibits water and salt intake.

Indifferent Phase

A period during the first 8 weeks of gestation when the sex of the embryo cannot be determined (gonads are still identical in both sexes).

Inhibin

A protein hormone secreted by sustenacular cells of the testes that acts to inhibit the release of FSH and LH from the anterior pituitary. Produced by seminiferous tubules and acts on the hypothalamus to slow production of the gonadotropin-releasing hormones that control the release of FSH. (negative feedback system)

Luteinizing Hormone

A protein hormone secreted by the anterior pituitary that stimulates ovulation in females and androgen production in males.

Atrial Natriuretic Factor

A protein hormone that is synthesized and released from the atria in response to high sodium concentration, high extracellular fluid volume, or high blood volume; it promotes sodium secretion and causes vasodilation in the circulatory system.

Prostate

A small gland encircling the male urethra just inferior to the bladder (only reproductive structure not paired). Its secretion contain nutrients and enzymes and account for approximately 35% of the ejaculate volume.

Morula

A solid ball of cells that makes up an embryo; in humans, this stage occurs within four days of fertilization.

Testosterone

A steroid hormone required for development of the male reproductive system, spermatogenesis, and male secondary sex characteristics; the major androgen in mammals.

Zona Pellucida.

A thick, transpartent coating rich in glycoproteins that surrounds an oocyte.

Cortisol

A type of glucocorticoid released by the adrenal cortex. It converts amino acids to glucose, helps to breakdown fats to fatty acids. Decreases glucose uptake by the muscles and increases blood sugar in response to stress. Strong anti-inflammatory properties.

Adrenal Medula

An endocrine organ that secretes epinephrine and norpinephrine in concert with the sympathetic nervous system.

Glycogen

An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch.

Primordial Follicles

Baby girls are born with about a million ______________, each containing an oocyte in arrested meiosis. The vast majority of primordial follicles never develop to the point of ovulation.

Sex Hormone Binding Globulin (SHBG)

Bind both testosterone and estrogen, higher affinity for testosterone. Synthesized in the liver.

FSH

Binds to the surface of Sertoli cells, stimulating adenylyl cyclase and thus activating the protein kinase A signaling pathway initiating spermatogenesis.

Prostacyclins

Biologically active substances produced by blood vessels that inhibit platelet aggregation (and therefore blood clotting), dilate blood vessels, and reduce blood pressure.

Thromboxanes

Biologically active substances produced in platelets that increase platelet aggregation (and therefore promote blood clotting), constrict blood vessels, and increase blood pressure.

Efferent

Carry or move away from a central structure.

Afferent

Carry or move inward or toward a central structure.

Angiotensin II

Causes vasoconstriction, remodeling, antinatriuresis, stimulation of salt appetite, ACTH secrection, and stimulation of AVP and OT.

5a-Reductase

Cell receptor that converts testosterone into 5a-dihydrogentestosterone (DHT) resulting in the masculinization of male genetalia.

Sertoli Cells

Cells located in the seminiferous tubules to nourish spermatids, FSH acts on these to promote spermatogenesis.

Chromosomal --> Gonadal --> Phenotypic

Central Dogma of Sexual Differentiation

Diabetes Insipidus

Characterized by the inability to produce a concentrated urine, frequent urination (with low specific gravity and osmolality), and often excessive thirst.

Turner Syndrome

Chromosomal disorder in phenotypic females that are short, lack a cycle (ammenorrhea), and lack secondary sexual charactaristics. Only have an X Chromosome.

Kleinfelter Syndrome

Chromosomal disorder resulting in an XXY karyotype. Subjects have male phenotype with small testis and decreased spermatagonia but otherwise normal. Generally have low testosterone and high estradiol levels. FSH is elevated.

Denys-Drash syndrome

Chromosomally XY males have ambiguousexternal genitalia. Dominant mutations in the WT1 gene disrupt normal testicular development.

Angiotensin I

Decapeptide resulting from the protolytic cleavage of angiotensinogen between Leu-10 and Val-11., Angiotensinogen (from liver) is converted to ________ by renin (from the kidney). Renin production is upregulated by high BP (sensed @ JG cells) and sympathetic tone; it is downregulated by Na+ delivery (sensed @ MD cells)

AVP

Decreases in blood volume unload the baroreceptors (decrease afferent flow), resulting in less inhibition ( α -adrenergic) of ________release and increased circulating _________.

Wolffian Duct

Develops into a system of connected organs between the efferent ducts of the testis and the prostate, namely the epididymis, the vas deferens, and the seminal vesicle. MIF inhibitory factor secreted by testosterone presence.

Primary Oocytes

Diploid cells resulting from the activation of anoogoium; primary oocytes are ready to enter meiosis I.

Spermatocyte

Diploid cells that divide by meiosis to produce four spermatids.

Antinatriuresis

Direct proximal tubule effect to stimulate sodium reabsorption and indirect effect via stimulation of aldosterone release and subsequent sodium reabsorption in distal tubule.

Syndrome of Persistent Mullerian Ducts

Disorder of Sexual differentiation (phenotypic) due to mutations in the production of AMH or AMH receptor causing the Mullerian ducts not to break down during male development. Can interfere with the decent of the testis.

5a Reductase Deficiency

Disorder of Sexual differentiation (phenotypic) due to the lack of the receptor necessary to convert testosterone to DHT.

Spermatogonium....spermatocytes....spermatids

Each ___________ undergoing differentiation gives rise to 16 primary ___________, each of which enters meiosis and gives rise to four ___________and ultimately four spermatozoa. Thus, 64 spermatocytes can develop from each spermatogonium.

Androgens

Enhance both the progesterone and estradiol secretion induced by FSH.

Cholesterol Side-Chain Cleavage Enzyme

Enzyme that converts pregnenolone to other steroid precursors.

Renin

Enzyme that is produced by the kidney (JG cells); important for blood pressure and volume regulation; catalyzes the conversion of circulating angiotensinogen to angiotensin I.

Complete Gonadal Dysgenesis

Gonadal disorder caused by faulty WT1, SF-1, SOX9, or DAX-1.

Pure Gonadal Disgenesis

Gonadal disorder where gonadal development stops before AMH/androgens are produced.

Antimullerian Hormone (AMH aka MIS)

Hormone secreted by sertoli cells which causes atrophy of mullerian ducts, preventing formation of female genital tract.

Mineralocorticoid

Hormone secreted by the adrenal cortex; regulates salts (electrolytes) and water balance in the body. Aldosterone is an example.

Estradiol (E2)

Induces proliferation and decreases apoptosis of the granulosa cells, maintains the responsiveness of these cells to FSH, and induces the formation of LH receptors.

DAX-1

Inhibits the expression of SF-1 target genes (opposite of SF-1). Made by X chromosome, _________ inhibits testis determining gene. SRY stops ________ from the development of the ovaries.

Relaxin

Inhibits uterine activity, diminishes the strength of the uterine contractions, aids in the softening of the cervix and has long-term effects of remodeling collagen; produced by the corpus luteum, the placenta and uterine deciduas.

Zona Reticularis

Inner layer of the adrenal cortex that secretes androgens and estrogens.

DHEA and DHEA-S

Item 3

Catecholamines

Item 4

Capsule

Item 5

Zona glomerulosa

Item 6

Zona fasciculata

Item 7

Zona reticularis

Item 8

Medula

Item 9

Mullerian Duct

One of a pair of tubes in the embryo that will develop, in female embryos, into the Fallopian tubes, uterus, and part of the vagina. Begin to form at 6 weeks of gestation.

Chorion

Outermost layer of the two membranes surrounding the embryo; it forms the fetal part of the placenta

Corticotropin Releasing Hormone

Produced by the hypothalamus signals the release of adrenocorticotropic hormone (ACTH) from the pituitary.

Gonadotropin- Releasing Hormone (GnRH)

Produced by the hypothalamus, this hormone stimulates the anterior pituitary to secrete FSH and LH.

Angiotensinogen

Prohormone produced by the liver then converted by renin to angiotensin I, then that is converted by ACE to angiotensin II.

Adrenomedullin (AM)

Proinflammatory cytokines such as interleukin-1 and TNF- α are potent stimulators of gene transcription and peptide release both from cultured vascular smooth muscle and endothelial cells in vitro and from the blood vessels in vivo.

Steroidogenic Acute Regulatory Protein (StAR)

Promotes the transfer of cholesterol from the outer to the inner mitochondrial membrane.

LH and FSH

Regulate the production of inhibin.

DHT

Responsible for virilization of the male external genetailia and prostate formation.

Hypovolemia (Low Blood Volume)

Results in renin release from the juxtaglomerular apparatus of the kidney and the formation of angiotensin II, both of which sensitize the osmoreceptor cells of the hypothalamus, leading to enhanced AVP release.

Sex Determining Region of the Y Chromosome

SRY

Scrotum

Skin-covered pouch in the groin divided into two sacs, each containing a testis and an epididymis.

Steroidogenic Acute Regulatory (StAR) protein

Th e rate-limiting step in steroid biosynthesis is the transfer of cholesterol from the outer mitochondrial membrane to the inner mitochondrial membrane, where the cholesterol side-chain cleavage enzyme (CYP11A) resides. Th is transfer is mediated by __________, and ACTH stimulates the levels of _________as part of its acute induction of steroidogenesis.

Dehydroepiandrosterone, produced by the adrenal; Androstenedione, derived from both the ovary and the adrenal; and Testosterone, which in addition to being produced by the ovary and adrenal is formed in peripheral tissues.

The 3 main circulating androgens in women.

Estradiol

The chief estrogen, females produce more than males, develops and maintains female secondary sex characteristics, important roles in menstruation and pregnancy

Urogenital Sinus

The common opening of the urinary and genital systems in the embryo.

Gluconeogenesis

The generation of glucose from non-sugar carbon substrates like pyruvate, lactate, glycerol, and amino acids The vast majority takes place in the liver and, to a smaller extent, in the cortex of kidney. This process occurs during periods of fasting, starvation, or intense exercise and is highly endergonic.

Urogenital Ridges

The genital and urinary system are derived from these folds created in the fourth week.

Adrenomedullin (AM)

The major effect of the hormone _____ on the kidneys is to increase Glomular filtration rate and renal blood flow and thereby indirectly stimulate the excretion of NaCl and water. A powerful vasodilator.

Corpus Luteum

The major source of progesterone secretion during the first 6-8 weeks of gestation.

Granulosa Cells

The majority of the cells surrouding an oocyte in a follicle and secrete estrogen during the follicular phase of the ovarian cycle (before ovulation).

Male pronucleus

The name for the nucleus of the spermatozoon after its head has penetrated into the ovum but before the nuclei of the ovum and the sperm have come together to restore the normal diploid chromosome number.

Acetylcholine

The neurotransmitter substance that is released at the synapses of parasympathetic nerves and at neuromuscular junctions.

Neurohypophysis

The posterior lobe of the pituitary (of neural origin)

Mesovarium

The posterior portion of the broad ligament that is drawn out to enclose and hold the ovary in place

Amnion

Thin innermost membranous sac enclosing the developing embryo

COX-2

This enzyme responsible for prostaglandin synthesis is responsible for additional prostaglandins in inflammatory diseases like arthritis. Nonsteroidal anti-inflammatory drugs (NSAID's) like aspirin and ibuprofen inactivate both COX-1 and COX-2, but increase risk for stomach ulcer formation.

Human Placental lactogen (hPL)

This hormone causes changes in maternal metabolism and causes decreased insulin sensitivity and utilization of glucose by mother. Helps make more glucose available to baby & also helps mother to prepare for lactation.

FGF9

This protein is induced by Sox9 and has positive feedback with Sox9 to promote testes development (sertoli cell).

Oxytocin

Vaginal stimulation during intercourse or delivery and stimulation of touch receptors in the nipples result in afferent neural input (via the spinothalamic tract and a variety of brain stem relays) to the producing cells in the paraventricular and supraoptic nuclei.

Inhibin

Within minutes of estrogen intravenous injection, LH levels begin to decline. However, FSH levels are not normalized by dministering estradiol to ovariectomized women. This is because the secretion of FSH is also under the inhibitory control of_______ which controls the secretion of FSH via a direct inhibitory action on the pituitary gonadotrophs.

Corpus Luteum

Yellow endocrine tissue that forms in a ruptured Graafian follicle following the release of an ovum.

Estradiol

________acts on both the hypothalamus and the anterior pituitary to inhibit gonadotropin secretion.

Oxytocin....Prolactin

________release is induced by audiovisual stimuli, such as seeing the baby or hearing its cry, or even by the anticipation of nursing while _______secretion is stimulated by suckling but not by audiovisual or psychological stimuli.

Five enzymatic steps are involved in the conversion of cholesterol to testosterone:

• Side-chain cleavage enzyme (CYP11A) • 3 β -hydroxysteroid dehydrogenase 2 (3β-HSD2) • 17 α -hydroxylase (CYP17) • 17,20-lyase (CYP17) • 17 β -hydroxysteroid dehydrogenase 3 (17β -HSD3).