endocrine-chap 16

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TH secretion abnormalaties can be caused by an abnormal antibody (_____________________________), that also promotes excessive thyroid growth by binding to the TSH receptor

(long acting thyroid stimulator: LATS)

the pancreas has both exocrine and endocrine cells, what are they?

-Acinar cells (exocrine) produce enzyme rich juice for digestion -Pancreatic islets (islets of langerhans) contain endocrine cells

what three levels does target cell activation depend on

-Blood levels of hormone -Relative number of receptors on or in target cell -Affinity of binding between receptor and hormone

Blood levels of hormones are -controlled by: -vary by:

-Controlled by negative feedback systems -Vary only within narrow, desirable range

what are other signal mechanisms?

-Cyclic guanosine monophosphate (cGMP) is second messenger for some hormones -Some work without second messengers E.g., insulin receptor is tyrosine kinase enzyme that autophosphorylates upon insulin binding docking for relay proteins that trigger cell responses

what are the causes of hyperinsulinism?

-Hypoglycemia (low blood glucose) -anxiety, nervousness, disorientation, unconsciousness, even death

Testosterone produced in the testes does what?

-Initiates maturation of male reporductive organs -causes apperance of male secondary sexual characteristics and sex drive -necessary for normal sperm production -maintains reproductive organs in functional state

the endocrine system controls and integrates:

-Reproduction -Growth and development -Maintenance of electrolyte, water, and nutrient balance of blood -Regulation of cellular metabolism and energy balance -Mobilization of body defenses

describe the onset of hormone activity

-Some responses ~ immediate -Some, especially steroid, hours to days -Some must be activated in target cells

Melatonin may affect

-Timing of sexual maturation and puberty -Day/night cycles -Physiological processes that show rhythmic variations (body temperature, sleep, appetite) -Production of antioxidant and detoxification molecules in cells

how do hormones alter target cell activity?

-alter plasma membrane permeability and/ or membrane potential by opening or closing ion channels -stimulate synthesis of enzymes or other proteins --activate or deactivate enzymes -induce secretory activity -stimulate mitosis

Insulin action on cells activates tyrosine kinase enzyme receptors which creates a cascade leading to increased glucose uptake into the cell. This triggers enzymes to:

-catalyze oxidation of glucose for ATP production (first priority) -polymerize glucose to form glycogen (next priority) -convert glucose to fat (particularly in adipose tissue) - last priority

Hormones are removed from the blood by

-degrading enzymes -kidneys -liver

what are the effects of cushings syndrome/disease?

-depresses cartilage and bone formation -inhibits inflammation -depresses immune system -disrupts cardiovascular, neural and gastrointestinal function -causes fat redistribution (buffalo hump)

the resistance phase of the stress response is the long term metabolic adjustment which involves glucocorticoids and glucagon (from the pancreas), and together they do what?

-eleate blood glucose concentration -liver synthesizes glucose from lipids, carbohydrates and amino acids

Insulin release is stimulated by

-elevated blood glucose levels (primary stimulus) -rising blood levels of amino acids and fatty acids -release of acetylcholine by parasympathetic nerve fibers -hyperglycemic hormones

Other hormone producing structures include the kidneys which produce what?

-erythropoietin (signals production of red blood cells) -renin (initiates the renin-angiotensin-aldosterone mechanism)

unless action is taken immediately in the exhaustion phase of the stress response, organs will begin to fail due to:

-exhaustion of lipid reserves -inability to produce gluccorticoids -failure of electrolyte balance -cumulative damage to vital organs

Other hormone producing structures include enteroendocrine cells of the gastrointestinal tract, what do they produce and what do they do?

-gastrin (stimulates release of HCl) -secretin (stimulates liver and pancreas) -cholecystokinin (stimulates pancreas, gallbladder, and hepatopancreatic sphincter) -Serotonin (acts as a paracrine)

insulin action on cells also works as a growth hormone, promoting:

-increased amino acid uptake -to increase protein synthesis -leaded to increased tissue growth (esp. in muscle)

Insulin release is inhibited by:

-low blood glucose -somatostatin (GHH) (secreted by delta islet cells) -sympathetic nervous system

insulin effects include:

-lowers blood glucose levles -enhances membrane transport of glucose into fat and muscle cells -inhibits glycogenolysis and gluconeogenesis -participates in neuronal development and learning and memory.

the resistance phase of the stress response is the long term metabolic adjustment which involves GH and glucocorticoids together which:

-mobilize the remaining energy reserves (lipids from dipose tissue & amino acids from skeletal muscle) -conserve glucose -peripheral tissues break down lipids or energy (not neural tissue)

What are the functions of the Parathyroid hormone? (PTH)

-stimulates osteoclasts to digest bone matrix and release Ca2+ into blood. -enhances reabsorption of Ca2+ and secretion of phosphate by kidneys -promotes activation of vitamin D (by kidneys); increases absorption of Ca2+ by intestinal mucosa

hormones act at receptors in one of two ways, depending on their chemical nature and receptor location, what are they?

-water soluble hormones (all amino acid-based hormones except thyroid hormone) -lipid soluble hormones (steroid and thyroid hormones)

Thyroid Hormone (TH): 1. Actually two related compounds: a.______ b.________ 2. Affects virtually very cell in _____________ 3. Major ___________ hormone 4. Increases metabolic rate and _____________ (calorigenic effect) 5. regulation of tissue __________ and ________ -development of skeletal and nervous systems -reproductive capabilities 6. Maintenance of blood _____________

1. a. T4 (thyroxine); has 2 tyrosine molecules + 4 bound iodine atoms b. T3 (triiodothyronine); has 2 tyrosines + 3 bound iodine atoms 2. body 3. metabolic 4. heat production 5. growth and development 6. pressure

Prolactin (PRL): 1. Regulation of PRL release: a. Primarily controlled by __________________ (dopamine) b. Release also inhibited by 2. Blood levels ________ toward end of pregnancy 3. Suckling stimulates ______________ and promotes continued milk production 4. Hypersecretion causes inappropriate lactation, lack of menses, infertility in females, and impotence in males 5. Hyporsecretion causes?

1. a. prolactin-inhibiting hormone (PIH) b. proesterone 2. rise 3. PRH release 5. nothing in males, and the inability to breastfeed in females

Melanocyte Stimulating Hormone (MSH): 1. Produced and secreted by anterior pituitary _________ (same cells thsat produce ACTH) 2. Targets Melanocytes of stratum basale to produce ___________ and darken skin 3. MSH is suppressed in most cases in humans and ________________________! 4. Hi levels of ____________ will cause MSH release, which darkens skin (Bronzing)

1. Corticotrophs 2. melanin 3. NOT A FACTOR 4. ACTHRH

The Pituitary gland (hypophysis) has two major lobes 1. ___________ made of ____________ tissue 2.___________ made of ____________ tissue

1. Posterior pituitary (lobe) Neural tissue 2. Anterior pituitary (lobe) (adenohypophysis) Glandular tissue

The Concentration of circulating hormone reflects 1.__________ 2.__________

1. Rate of release 2. Speed of inactivation and removal from body

Mechanisms of Aldosterone Secretion

1. Renin-angiotensin mechanism (decreased blood pressure stimulates kidneys to releases renin, triggers formation of angiotensin 2, potent stimulator of aldosterone release) 2. Plasma concentration of K+, (increased K+ directly influences zona glomerulosa cells to release aldosterone) 3. ACTH (causes small increases of aldosterone during stress) 4. Atrial natriuretic peptide (ANP) (blocks renin and aldosterone secretion to decrease BP)

What are the 5 anterior pituitary cell types and what do they secrete?

1. Somatotrophs Secrete Human Growth Hormone (hGH) 2. Thyrotrophs Secrete Thyroid Stimulating Hormone (TSH) 3. Gonadotrophs Secrete Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH) 4.Lactotrophs (Prolactin cells) Secrete Prolactin (PRL) 5. Corticotrophs Secrete Adrenocorticotropic Hormone (ACTH) and Melanocyte Stimulating Hormone (MSH)

the adrenal (suprarenal) glands are structurally and functionally two glands in one: 1. ____________-nervous tissue; part of sympathetic nervous system 2._____________-three layers of glandular tissue that synthesize and secrete corticosteroids

1. adrenal medulla 2. adrenal cortex

The pancreas has both exocrine (acinar cells) and endocrine (pancreatic islets/islets of langerhans) cells. Define these parts of the pancreatic islets/islets of langerhans cells: 1._____________ 2._______________ 3.____________

1. alpha cells produce glucagon (hyperglycemic hormone) 2. beta cells produce insulin (hypoglycemic hormone) 3. PP cells (formerly F cells) produce pancreatic polypeptide-regulates pancreatic and gastric function

Synthesis of Thyroid Hormone: 1. thyroid gland stores hormone ____________ 2. thyroglobulin synthesized and dischared into ____________ 3. __________ (I-) actively taken into cell and released into lumen 4. Iodide oxidized to _____________ (I2) 5. Iodine attaches to tyrosine, mediated by peroxidase ___________ 6. Iodinated tyrosines link together to form ________ and ________ 7. colloid is endocytosed and vesicle is combined with a ___________ 8. T3 and T4 are cleaved and diffuse into _________.

1. extracellularly 2. follicle lumen 3. Iodides 4. Iodine 5. enzymes 6. T3 and T4 7. lysosome 8. bloodstream

What are the 6 anterior pituitary hormones?

1. growth hormone (GH) 2. thyroid stimulating hormone (TSH) or thyrotropin 3. adrenocorticotropic hormone (ACTH) 4. follicle stimulating hormone (FSH) 5. luteinizing hormone (LH) 6. prolactin (PRL)

Aldosterone stimulates Na+ reabsorption and water retention by kidneys; elimination of K+ 1.___________ blood volume 2. __________ blood Na+ 3. __________ blood K+

1. increases 2. increases 3. decreases

Thyroid gland: 1. Two lateral lobes connected by median mass called _________ 2. Composed of follicles that produce glycoprotein _________________ 3. Colloid (fluid with thyroglobulin + iodine) fills lumen of follicles and is precursor of _____________________ 4. Parafollicular cells produce the hormone _________

1. isthmus 2. thyroglobulin 3. thyroid hormone 4. calcitonin

The Posterior pituitary (lobe): 1. is a downgrowth of hypothalamic _________ tissue 2. it has a neural connection to hypothalamus called the ____________________________________ 3. the nuclei of hypothalamus synthesize neurohormones ________ and ________________ (___) 4. Neurohormones are transported and stored in ____________________ and they are transported through ___________________________ 5.when hypothalamic neurons fire, action potentials arriving and the axon terminals cause ________________ or ___________ to be released in the blood

1. neural 2. hypothalamic-hypophyseal tract 3. oxytocin and antidiuretic hormone (ADH) 4. posterior pituitary, Hypothalamic-hypophyseal tract 5. oxytocin or ADH

The anterior lobe: 1. originates as outpocketing of _________________ 2. it has a ____________ connection to hypothalamus, a Hypophyseal portal system consists of the _________,_____________ and a ________________. and carries releasing and inhibiting hormones to the __________________ to regulate hormone secretion.

1. oral mucosa 2. vascular, a primary capillary plexus, hypophyseal portal veins and a secondary capillary plexus. anterior pituitary.

signs and symptoms of hyperglycemia include:

1. polyuria 2. polydisia 3. polyphagia

1. When appropriately stimulated, hypothalamic neurons secrete releasing or inhibiting hormones into the __________________________. 2. Hypothalamic hormones travel through portal veins to the anterior pituitary where they stimulate or inhibit release of hormones made in the ___________________. 3. In response to releasing hormones, the anterior pituitary secretes hormones into the ________________________. This in turn empties into the general circulation.

1. primary capillary plexus 2. anterior pituitary. 3. secondary capillary plexus

Prolactin (PRL): 1. Secreted by ________________ of anterior pituitary 2. Stimulates milk production in ______________ -slight inhibition of FSH, though not reliable to prevent ____________ 3. Role in males not well understood

1. prolactin cells (lactotrophs) 2. mammilary glands -follicle development

Anterior Pitutary hormones: 1. All are ________ 2. All except GH activate _________________ at their targets 3. TSH, ACTH, FSH, and LH are all __________ hormones (regulate secretory action of other endocrine glands)

1. proteins 2. cyclic AMP second-messenger systems 3. tropic

exposure to stressors will produce the same general pattern of hormonal and physiological adjustments, these responses are part of the general adaptive syndrome aka the stress response. it can be divided into three phases 1._______________ 2._______________ 3.________________

1. the alarm phase 2. the resistance phase 3. the exhaustion phase

Transport and Regulation of TH: 1. T4 and T3 transported in the blood by _____________________ (TBGs) 2. Both bind to target receptors, but ___ is ten times more active than ___ 3. _________ tissues convert T4 to T3 4.Negative feedback regulation of TH release: -Rising TH levels provide _________________ on release of TSH -_______________ (TRH) can overcome negative feedback during pregnancy or exposure to cold

1. thyroxine-binding globulins (TBGs) 2. T3, T4 3. -negative feedback inhibition -Hypothalamic thyrotropin-releasing hormone

what are the 3 layers of the adrenal cortex and the corticosteroids they produce?

1. zona glomerulosa-mineralocorticoids 2. zona fasciulata-glucocorticoids 3. zona reticularis-gonadocorticoids

Inhibits or prevents urine formation

ADH (Vasopressin)

Release also triggered by pain, low blood pressure, and drugs

ADH (Vasopressin)

high concentrations lead to vasoconstriction

ADH (Vasopressin)

regulates water balance

ADH (Vasopressin)

targets kidney tubules to reabsorb more water by increasing production of aquaporin channels in kidney tubules which increases blood volume.

ADH (Vasopressin)

Inhibited by alcohol, diuretics

ADH (vasopressin)

diabetes insipidus is an ____________________ due to hypothalamus or posterior damage, the person effected must stay well hydrated because they cant reabsorb water into their kidneys, they just pee it all out

ADH deficiency

what are the two main classes of hormones?

Amino acid-based hormones and steroids

Other hormone producing structures include the heart which produces ________________ which decreases blood Na+ concentration, therefore blood pressure and blood volume

Atrial natriuretic peptide (ANP)

medullary chromaffin cells synthesize epinephrine (Adrenalin) (80%) and norepinephrine (20%) in the adrenal medulla, norepinephrine nfluences peripheral vasoconstriction and blood pressure. -tends to increase __________ to maintain profusion during fight of flight response

what glucocorticoid is released in response to ACTH, patterns of eating and activity, and stress

Cortisol

PTH doesnt have to regulate Ca2+ levles very closely. (T/F)

What is hypoparathyroidism? what does it result in?

Follows gland trauma or removal or dietary magnesium deficiency. results in tetany, respiratory paralysis, and death

___________ chiefly regulated by hypothalamic hormones - growth hormone-releasing hormone (GHRH)stimulates release -Growth hormone-inhibiting hormone (GHIH) (somatostatin) inhibits release -negative feedback

GH release

the resistance phase of the stress response is the long term metabolic adjustments which involves the release of _____________ and _____________ (same as ____________) from the hypothalamus. -this stimulates the release of _______________ and _______________ (by way of ACTH).

GHRH and CRH (same as ACTHRH) -growth hormone and glucocorticoids

regulation of ___________________: a. triggered by the gonadotropin-releasing hormone (GnRH) during and after puberty b. suppressed by gonadal hormones (feedback) -simple negative feedback in males -more complicated regulation in females

Gonadotropin release

FSH stimulates gamete (egg or sperm) production

Gonadotropins

LH promotes production of gonadal hormones

Gonadotropins

Secreted by gonadotropic cells of anterior pituitary

Gonadotropins

Follicle-stimulating hormone (FSH) and luteinizing hormone (LH)

Gonadotropins:

All metabolic effect tend to increase glucose levels (anti-insulin effects)

Growth Hormone (GH, or Somatotropin)

Produced by somatotropic cells

Growth Hormone (GH, or Somatotropin)

direct actions on metabolism -increases blood levels of fatty acids; encourages use of fatty acids for fuel -decreases rate of glucose uptake and metabolism, conserving glucose -Glycogen breakdown and glucose release to blood

Growth Hormone (GH, or Somatotropin)

indirect actions on growth -mediates growth via growth promoting proteins - insulin-like growth factors (IGFs) -IGFs stimulate --uptake of amino acids for protein synthesis --formation of collagen (epiphyseal plate) and deposistion of bone matrix -major targets are bone, skeletal muscle, and cartilage

Growth Hormone (GH, or Somatotropin)

Ghrelin (a hunger hormone) also stimulates release of what?

Growth Hormone (GH, or Somatotropin):

Other Hormone-Producing Structures

Heart - ANP Gastrointestinal tract - enteroendocrines Placenta - estrogens, progesterone Kidney - erythropoietin Skin - cholecalciferol Adipose tissue - leptin, resistin

define hormonal stimuli -hypothalamic hormones stimulate release of most: -anterior pituitary hormones stimulate targets to: -Hypothalamic-pituitary-target endocrine organ feedback loop:

Hormones stimulate other endocrine organs to release their hormones -Hypothalamic hormones stimulate release of most anterior pituitary hormones -Anterior pituitary hormones stimulate targets to secrete still more hormones (Tropic Hormones) -Hypothalamic-pituitary-target endocrine organ feedback loop: hormones from final target organs inhibit release of anterior pituitary hormones

What is aldosteronism?

Hyper-secretion due to adrenal tumors - Hypertension and edema due to excessive Na+ - Excretion of K+ leading to abnormal function of neurons and muscle

The Parathyroid hormone (PTH) uses ______________: rising Ca2+ in blood inhibits PTH release.

Negative feedback control

The posterior pituitary and hypothalamic hormones are ________________ and ______________, Each composed of nine amino acids and Almost identical - except they differ in ____________________.

Oxytocin and ADH 1. nine amino acids 2. differ in two amino acids

What does osteocalcin do?

Prods pancreas to secrete more insulin; restricts fat storage; improves glucose handling; reduces body fat

the duration of hormone activity is limited, how?

Ranges from 10 seconds to several hours Effects may disappear as blood levels drop

the resistance phase of the stress response is the long term metabolic adjustment which involves sympathetic stimulation causes the activation of _______________________ system to produce aldosterone and ADH. -for the conservation of _____________ and __________ -____________ and _____________ are lost

Renin-Angiotensin -water and salts -K+ and H+

Multiple hormones may act on the same target at the same time. (T/F)

what is target cell specificity? for example: -ACTH receptors found: -Thyroxin receptors found:

Target cells must have specific receptor to which hormone binds.for example: -ACTH receptors found only on certain cells of adrenal cortex -Thyroxin receptors are found on nearly all cells of body

Release triggered by thyrotropin releasing hormone from hypothalamus