Endocrine System Pt.2

Question 1

Thyroid gland is composed of…

Answer 1

-isthmus
-composed of follicles that produce glycoprotein thyroglobulin
-colloid (fluid with thyroglobulin + iodine) fills lumen of follicles and is precursor for TH
-parafollicular cells produce hormone calcitonin

Question 2

Isthmus

Answer 2

2 lateral lobes connected by median mass

Question 3

Thyroid hormone (TH) includes

Answer 3

Thyroxine (T4) and triiodothyronine (T3) which increase rate of cellular metabolism. Consequently, oxygen use and heat production rise

Question 4

Effects of T3 and T4 on basal metabolic rate (BMR)/ temp. Regulation

Answer 4

Normal: promotes normal o2 use and BMR; calorigenesis; enhances effects of SNS

Hypo: BMR below normal; decreases body temp, cold intolerance; decreases appetite; weight gain; reduced sensitivity to catecholamine

Hyper: BMR above normal; increased body temp., heat intolerance; increased appetite; weight loss

Question 5

Effects of T4 and T3 on carb/lipid/protein metabolism

Answer 5

Normal: promotes glucose catabolism; mobilizes fats: essential for protein synthesis: enhances liver’s synthesis of cholesterol

Hypo: decreases glucose metabolism; elevated cholesterol/triglyceride levels in blood; decreases protein synthesis; edema

Hyper: enhanced catabolism of glucose, proteins, and fats; weight loss; loss of muscle mass

Question 6

Effects of T4 and T3 on NS

Answer 6

Normal: promotes normal development of NS in fetus and infant; promotes normal adult NS production

Hypo: in infant, slowed/deficient brain development, intellectual disability; in adults, mental dulling, depression, paresthesias, memory impairment, hypoactive reflexes

Hyper: irritability, restlessness, insomnia, personality changes exophthalmos (in Graves’ disease)

Question 7

Effects of T4 and T3 on NS

Answer 7

Normal: promotes normal development of NS in fetus and infant; promotes normal adult NS production

Hypo: in infant, slowed/deficient brain development, intellectual disability; in adults, mental dulling, depression, paresthesias, memory impairment, hypoactive reflexes

Hyper: irritability, restlessness, insomnia, personality changes exophthalmos (in Graves’ disease)

Question 8

Thyroid Hormone (TH)

Answer 8

-2 related compounds:
-T4 (thyroxine); has 3 tyrosine molecules + 4 bound iodine atoms
-T3 (triiodothyronine), has 2 tyrosines + 3 bound iodine atoms
-major metabolic hormone
-increases metabolic rate and heat production (calorigenic effect)
-regulation of tissue growth and development:
-development of skeletal and NS
-Reproductive capabilities
-maintenance of blood pressure

Question 9

Effects of T4 and T3 on ❤️ system

Answer 9

Normal: promotes normal functioning of the ❤️

Hypo: decreased efficiency of ❤️s pumping action; low ❤️ rate and blood pressure

Hyper: increased sensitivity to catecholamines can lead to rapid ❤️ rate, palpitations, high blood pressure, and ❤️ failure

Question 10

Synthesis of TH

Answer 10

-thyroid gland stores hormone extra cellularly
-thyroidglobulin synthesizedand discharged into follicle lumen
-iodides (I-) actively taken into cell and released into lumen
-iodides oxidized to iodine (I2)
-iodine attaches to tyrosine, mediated by perioxidase
-iodinated tyrosines link together to form T3 and T4
-colloid is endocystosed and vesicle is combined with a lysosome
-T3 and T4 are cleaved and diffused into bloodstream

Question 11

Effects of T4 and T3 on muscular system

Answer 11

Normal: promotes normal muscular development and function

Hypo: sluggish muscle action; muscle cramps; myalgia

Hyper: muscle atrophy and weakness

Question 12

Transport and regulation of TH

Answer 12

-T4 and T3 transported in the body by thyroxine-binding globulins (TBGs)
-both bind to target receptors, but T3 is 10x more active than T4
-peripheral tissues convert T4 to T3
-(-) feedback regulation of TH:
-rising TH levels provide (-) feedback inhibition on release of TSH
-hypothalamic thyrotropin-releasing hormone (TRH) can overcome (-) feedback during pregnancy or exposure to cold

Question 13

Effects of T4 and T3 on Skeletal system

Answer 13

Normal: promotes normal growth and maturation of skeleton

Hypo: in child, growth retardation, skeletal stunting and retention of child’s body proportions; in adults: joint pain

Hyper: in child: excessive skeletal growth, initially, followed by early epiphyseal closure and short stature; in adult: demineralization of skeleton

Question 14

Homeostatic imbalances of TH

Answer 14

-Hypo in adults:
-pts are cold, fatigued and overweight
-myxedema; goiter if due to lack of iodine
-hashimotos- TSH receptor is blacked by abnormal antibody
-hypo in infants- cretinism
-hyper- graves:
-underweight, hot, anxious with voracious appetite
-exophthalmos
-can have goiter
-can be caused by abnormal antibody (long acting thyroid stimulator; LATS)
-also promotes excessive thyroid growth by binding to TSH receptor

Question 15

Effects of T4 and T3 in GI system

Answer 15

Normal: promotes normal GI motility and tone; increases secretion of digestive juices

Hypo: depressed GI motility, tone, and secretory activity; constipation

Hyper: excessive GI motility; diarrhea

Question 16

Effects of T4 and T3 in GI system

Answer 16

Normal: promotes normal GI motility and tone; increases secretion of digestive juices

Hypo: depressed GI motility, tone, and secretory activity; constipation

Hyper: excessive GI motility; diarrhea

Question 17

Calcitonin

Answer 17

-produced by parafollicular (c) cells
-no known physiological role in humans
-antagonist to parathyroid hormone (PTH)
-at higher than normal doses:
-inhibits osteoclast activity and release of Ca2+ from bone matrix
-stimulates Ca2+ uptake and incorporation into bone matrix

Question 18

Calcitonin

Answer 18

-produced by parafollicular (c) cells
-no known physiological role in humans
-antagonist to parathyroid hormone (PTH)
-at higher than normal doses:
-inhibits osteoclast activity and release of Ca2+ from bone matrix
-stimulates Ca2+ uptake and incorporation into bone matrix

Question 19

Effects of T4 and T3 on. Reproductive system

Answer 19

Normal: promotes normal female reproductive ability and lactation

Hypo: depressed ovarian function: sterility; depressed lactation

Hyper: in females: depressed ovarian function; in males; impotence

Question 20

Effects of T4 and T3 on integumentary system

Answer 20

Normal: promotes normal hydration and secretory activity of skin

Hypo: skin pale, thick, and dry; facial edema; hair coarse and thick

Hyper: skin flushed, this, and moist; hair fine and soft; nails soft and thin

Question 21

Parathyroid glands

Answer 21

-4-8 tiny glands embedded in posterior aspect of thyroid
-Contain oxyphil cells (function unknown) and parathyroid cells that secrete parathyroid hormone (PTH) or parathormone
-PTH—most important hormone in Ca2+ homeostasis

Question 22

Secretion of thyroid hormone, promoted by TSH, requires…

Answer 22

Follicular cells to take up the stored colloid and split the hormones from the colloid for release. Rising levels of TH feedback to inhibit the anterior pituitary and hypothalamus

Question 23

Parathyroid hormone

Answer 23

Functions
• Stimulates osteoclasts to digest bone matrix and release Ca2+ to:
-Enhances reabsorption of Ca2+ and secretion of phosphate by kidneys
-Promotes activation of vitamin D (by kidneys); increases absorption of Ca2+ by intestinal mucosa
• Negative feedback control: rising Ca2+ in blood inhibits PTH release

Question 24

Homeostatic imbalances of PTH

Answer 24

-Must regulate Ca2+ levels very closely
-Hyperparathyroidism due to tumor
-Bones soften and deform
-Elevated Ca2+ depresses nervous system and contributes to formation of kidney stones
-Hypoparathyroidism following gland trauma or removal or dietary magnesium deficiency
-Results in tetany, respiratory paralysis

Question 25

What is the difference between T3 and T4? Which one of these is referred to as thyroxine?

Answer 25

T4 has 4 bound iodine atoms, and T3 has 3. T4 is the major hormone secreted, but T3 is more potent. T4=thyroxine

Question 26

Why does TH require plasma proteins in order to move through blood? Where are the receptors for TSH located?

Answer 26

TH must be carried through🩸by plasma proteins b/c it is lipid soluble and so does not readily dissolve in 🩸, which is mostly💧. The receptors for TSH are located on plasma membrane of the thyroid follicle cells (on the sides facing away from colloid- TSH is 💧-soluble hormone from anterior pituitary)

Question 27

Adrenal (suprarenal) glands

Answer 27

-Paired, pyramid-shaped organs atop kidneys -Structurally and functionally are two glands in one -Adrenal medulla—nervous tissue; part of sympathetic nervous system -Adrenal cortex—three layers of glandular tissue that synthesize and secrete corticosteroids

Question 28

Parathyroid glands

Answer 28

-Located on dorsal aspect of thyroid gland -secrete PTH- increases 🩸calcium levels -targets bone, kidneys, and small intestine (indirectly via Vit D activation) -PTH= key hormone for calcium homeostasis

Question 29

Adrenal cortex

Answer 29

-Three layers and corticosteroids produced 1) Zona glomerulosa—mineralocorticoids 2) Zona fasciculata—glucocorticoids 3) Zona reticularis—gonadocorticoids

Question 30

PTH release and inhibit

Answer 30

Falling 🩸calcium levels trigger PTH release; rising 🩸 calcium levels inhibit its release

Question 31

Mineralocorticoids

Answer 31

-Regulate electrolytes (primarily Na+ and K+) in ECF -Importance of Na+: affects ECF volume, blood volume, blood pressure, levels of other ions -Importance of K+: sets RMP -Aldosterone most potent mineralocorticoid -Stimulates Na+ reabsorption and water retention by kidneys; elimination of K+ -Increases blood volume -Increases blood Na+ -Decreases blood K+

Question 32

Hyperparathyroidism results in…

Answer 32

Hypercalcemia and extreme bone wasting

Question 33

Hypoparathyroidism leads to…

Answer 33

Hypocalcemia, evidenced by tetany and respiratory paralysis

Question 34

Aldosterone

Answer 34

Release triggered by: • Decreasing blood volume and blood pressure • Rising blood levels of K+

Question 35

Paired adrenal (suprarenal) glands

Answer 35

Sit atop the kidneys. Each adrenal gland has 2 functional portions, the cortex and medulla

Question 36

Indicated general functions of parathyroid hormone

Answer 36

-raises 🩸 calcium -stimulates release of calcium from bones -indirectly increases activity of AND # of osteoclasts -stimulates reabsorption of calcium by kidneys -stimulates final conversion of vit d in kidneys -calcidiol into calcitriol -calcitriol aids calcium absorption in small intestines -decreases 🩸 phosphate -stimulates release of phosphate from bones and absorption of phosphate in the gut -stimulates secretion of phosphate by kidneys -amount secreted by kidneys exceeds the amount being released/reabsorbed, leading to OVERALL decrease in 🩸 phosphate levels

Question 37

Mechanisms of aldosterone secretion

Answer 37

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

Question 38

What is the major effect of TH? PTH? Calcitonin?

Answer 38

TH: increase basal metabolic rate (and heat production) in the body. PTH: increases 🩸 Ca2+ levels in variety of ways Calcitonin at high levels (pharmacological) has Ca2+- lowering, bone-sparing effects (at normal levels, no effects on humans)

Question 39

Homeostatic imbalances of aldosterone

Answer 39

Aldosteronism—hypersecretion due to adrenal tumors • Hypertension and edema due to excessive Na+ • Excretion of K+ leading to abnormal function of neurons and muscle

Question 40

Name the cells that release TH, PTH, and calcitonin?

Answer 40

-thyroid follicular cells release TH -parathyroid cells in parathyroid gland release PTH -parafollicular (C) cells in the thyroid gland release calcitonin

Question 41

Glucocorticoids

Answer 41

-Keep blood glucose levels relatively constant -Maintain blood pressure by increasing action of vasoconstrictors -Cortisol (hydrocortisone) -Cortisone -Corticosterone -Normal levels maintained by negative feedback

Question 42

Glucocorticoids

Answer 42

-Keep blood glucose levels relatively constant -Maintain blood pressure by increasing action of vasoconstrictors -Cortisol (hydrocortisone) -Cortisone -Corticosterone -Normal levels maintained by negative feedback

Question 43

List hormones produced by adrenal gland and their physiological effects

Answer 43

Aldosterone- helps kidneys control their amount of salt in the 🩸 and tissues in the body Cortisol- helps the body manage and use carbs, proteins, and fats. Adrenaline

Question 44

List the 3 classes of hormones released from the adrenal cortex and briefly state the major effects of each?-

Answer 44

Glucocorticoids are stress hormones that, among many effects, increase 🩸 glucose. Mineralocortoids increase 🩸 Na+ (and 🩸 pressure) and decrease 🩸 K+ Gonadcorticoids are male and female sex hormones that are thought to have a variety of effects

Question 45

Glucocorticoids: cortisol

Answer 45

Released in response to ACTH, patterns of eating and activity, and stress • Prime metabolic effect is gluconeogenesis—formation of glucose from fats and proteins -Promotes rises in blood glucose, fatty acids, and amino acids • "Saves" glucose for brain • Enhances vasoconstriction à rise in blood pressure to quickly distribute nutrients to cells • Powerful anti-inflammatory – reduces effects of histamine • Suppresses the immune system – reduces the activity of T and B cells • Inhibits healing • Alters mood • Increases appetite

Question 46

Mineralocortoids (chiefly aldosterone) regulation of release

Answer 46

Stimulates by renin-angiotensin-aldosterone mechanism (activated by decreasing 🩸volume or 🩸 pressure), elevated 🩸 K+ levels, and ACTH (minor influence)

Question 47

Mineralocortoids (chiefly aldosterone/ adrenocortical hormones) regulation of release

Answer 47

Stimulates by renin-angiotensin-aldosterone mechanism (activated by decreasing 🩸volume or 🩸 pressure), elevated 🩸 K+ levels, and ACTH (minor influence) Inhibited by increasing 🩸 pressure, decreases 🩸 K+ levels

Question 48

Homeostatic imbalances of glucocorticoids

Answer 48

-Hypersecretion—Cushing's syndrome/disease -Depresses cartilage and bone formation -Inhibits inflammation -Depresses immune system -Disrupts cardiovascular, neural, and gastrointestinal -Fat redistribution -Buffalo hump -Hyposecretion—Addison's disease -Decrease in glucose and Na+ levels -Difficulty handling chronic stress -Extreme fatigue -Weight loss -Hyperpigmentation -Also involves deficits in mineralocorticoids -Decreased Na+ levels -Severe dehydration, and hypotension

Question 49

Homeostatic imbalances of glucocorticoids

Answer 49

-Hypersecretion—Cushing's syndrome/disease -Depresses cartilage and bone formation -Inhibits inflammation -Depresses immune system -Disrupts cardiovascular, neural, and gastrointestinal -Fat redistribution -Buffalo hump -Hyposecretion—Addison's disease -Decrease in glucose and Na+ levels -Difficulty handling chronic stress -Extreme fatigue -Weight loss -Hyperpigmentation -Also involves deficits in mineralocorticoids -Decreased Na+ levels -Severe dehydration, and hypotension

Question 50

Mineralcorticoids target organ and effects

Answer 50

Kidneys: increase 🩸 levels of Na+ and b decrease 🩸 levels of K+ Since 💧 reabsorption usually accompanies sodium retention, 🩸 volume and 🩸 pressure rise

Question 51

Gonadocorticoids (Sex Hormones)

Answer 51

-Most weak androgens (male sex hormones) converted to testosterone in tissue cells, some to estrogens -May contribute to: -Onset of puberty -Appearance of secondary sex characteristics -Sex drive in women

Question 52

Gonadocorticoids (Sex Hormones)

Answer 52

-Most weak androgens (male sex hormones) converted to testosterone in tissue cells, some to estrogens -May contribute to: -Onset of puberty -Appearance of secondary sex characteristics -Sex drive in women

Question 53

Mineralocorticoids effects of hyper and hypo secretion

Answer 53

Hyper: aldosteronism Hypo: Addison’s disease

Question 54

What are the 2 major stimuli for aldosterone release? What is the major stimulus for cortisol release?

Answer 54

Aldosterone: 1) decrease in 🩸 blood volume or 🩸 pressure, which triggers the renin-angiotensin-aldosterone mechanism 2)increase in plasma K+ levels Cortisol: ACTH from anterior pituitary- in turn is controlled by CRH from hypothalamus. CRH release follows a diurnal (day-night) rhythm and is increased in response to various stressors, as well as by hypoglycemia and fever

Question 55

Gonadocortoids hypersecretion

Answer 55

-Adrenogenital syndrome (masculinization) -Not noticeable in adult males -Females and prepubertal males -Boys – reproductive organs mature; secondary sex characteristics emerge early -Females – beard, masculine pattern of body hair; clitoris resembles small penis

Question 56

Glucocorticoids (chiefly cortisol/ adrenocortical hormone) regulation of release

Answer 56

Stimulated by ACTH Inhibited by feedback inhibition exerted by cortisol

Question 57

Adrenal medulla

Answer 57

-Medullary chromaffin cells synthesize epinephrine (80%) and norepinephrine (20%) -Effects -Vasoconstriction -Increased heart rate -Increased blood glucose -Blood diverted to brain, heart, and skeletal muscle -Released in response to acute (short term) stress (fight or flight) -Responses brief -Epinephrine stimulates metabolic activities, bronchial dilation, and blood flow skeletal muscles and the heart -Norepinephrine influences peripheral vasoconstriction and blood pressure -Tends to increase BP to maintain profusion during fight or flight response

Question 58

Glucocorticoids target organ and effects

Answer 58

Body cells: promotes gluconeogenrsis and hyperglycemia; mobilizes fats for energy metabolism; stimulate protein catabolism; assist body to resist stressors; depress inflammatory and immune responses

Question 59

Stress and the general adaptive syndrome

Answer 59

-Any condition, Physical or emotional, that threatens homeostasis is a form of STRESS -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 ▪ The Alarm Phase ▪ The Resistance Phase ▪ The Exhaustion Phase

Question 60

Glucocorticoids effects of hyper and hyposecretion

Answer 60

Hyper: Cushing’s Hypo: Addison’s

Question 61

The Alarm Phase

Answer 61

-The immediate short-term response to a crises which involves: ▪ General sympathetic activation ▪ With epinephrine and norepinephrine release from the adrenal medulla -This leads to: ▪ Increased mental alertness ▪ Increased energy use by all cells ▪ Glycogen and lipid reserve mobilization ▪ Changes in circulation ▪ Decreased digestive activity and urine production ▪ Increased sweat gland secretion ▪ Increases in heart and respiratory rates

Question 62

Gonadocorticoids (chiefly androgens, converted to testosterone or estrogens after release/ Adrenocortical hormones) regulation of release

Answer 62

Stimulated by ACTH; mechanism of inhibition incompletely understood, but feedback inhibition not seen

Question 63

The Resistance Phase

Answer 63

-The long-term metabolic adjustments which involves: -The release of GHRH and CRH (same as ACTHRH) from the hypothalamus -This inhibits the release of Growth Hormone and glucocorticoids (by way of ACTH). -Sympathetic stimulation causes the activation of the Renin-Angiotensin system to produce Aldosterone and ADH -For the conservation of water and salts -K+ and H+ are lost -GH and glucocorticoids together: -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 -Glucocorticoids and Glucagon (from the pancreas) together: -Elevate blood Glucose Concentration: -Liver synthesizes glucose from: -Lipids -Carbohydrates

Question 64

Gonadocorticoids target organ and effects

Answer 64

Insignificant effects in males; contributes to female libido; development of pubic and axillary hair in females; source of estrogens after menopause

Question 65

Exhaustion Phase

Answer 65

▪ When the resistance phase ends homeostatic regulation breaks down ▪ Unless action is taken immediately, organ systems will begin to fail Due to: -Exhaustion of energy reserves -Inability to produce glucocorticoids -Failure of electrolyte balance (Why?) -Cumulative damage to vital organs ▪ If not treated immediately it will lead to death

Question 66

Gonadocorticoids effects of hypersecretion

Answer 66

Hyper: masculinization of females (adrenogenital syndrome)

Question 67

Pineal Gland

Answer 67

-Small gland hanging from roof of third ventricle -Pinealocytes secrete melatonin, derived from serotonin -Melatonin may affect -Timing of sexual maturation and puberty -Day/night cycles -In darkness melatonin is released causing sleepiness -Light impulses from the retina suppress melatonin release – Physiological processes that show rhythmic variations (body temperature, sleep, appetite) –(Supplements?) – production of antioxidant and detoxification molecules in the liver

Question 68

Catecholamines (epinephrine and norepinephrine/ adrenal medullary hormone)

Answer 68

Stimulated by preganglionic fibers of SNS

Question 69

Pancreas

Answer 69

• Triangular gland partially behind stomach • Has both exocrine and endocrine cells -Acinar cells (exocrine) produce enzyme-rich juice for digestion -Pancreatic islets (islets of Langerhans) contain endocrine cells -Alpha (a) cells produce glucagon (hyperglycemic hormone) -Beta (b) cells produce insulin (hypoglycemic hormone) -PP cells (formerly F cells) produce pancreatic polypeptide - regulates pancreatic and gastric function

Question 70

Catecholamines target organ and effects

Answer 70

SNS target organs: effects mimic SNS activation; increase ❤️ rate and metabolic rate; increase 🩸 pressure by promoting vasoconstriction

Question 71

Glucagon

Answer 71

• Major target liver • Causes increased blood glucose levels • Effects -Glycogenolysis—breakdown of glycogen to glucose -Gluconeogenesis—synthesis of glucose from lactic acid and noncarbohydrates -Release of glucose to the 🩸

Question 72

Glucagon

Answer 72

• Major target liver • Causes increased blood glucose levels • Effects -Glycogenolysis—breakdown of glycogen to glucose -Gluconeogenesis—synthesis of glucose from lactic acid and noncarbohydrates -Release of glucose to the 🩸

Question 73

Catecholamines effects of hypersecretion

Answer 73

Hyperglycemia, increased metabolic rate, rapid heartbeat and palpitations, hypertension, intense nervousness, sweating (prolonged fight or flight)

Question 74

Catecholamines effects of hypersecretion

Answer 74

Hyperglycemia, increased metabolic rate, rapid heartbeat and palpitations, hypertension, intense nervousness, sweating (prolonged fight or flight)

Question 75

Insulin

Answer 75

• Effects of insulin (51 Amino Acid protein) -Lowers blood glucose levels -Enhances membrane transport of glucose into fat and muscle cells -Inhibits glycogenolysis and gluconeogenesis -Participates in neuronal development and learning and memory • Not needed for glucose uptake in liver, kidney or brain -These organs are insulin independent

Question 76

Adrenal cortex, adrenal medulla, anterior pituitary, and posterior pituitary: which part of the glands release steroid hormones? Amino acids-based hormones?

Answer 76

Adrenal cortex released steroid hormones Adrenal medulla, anterior, and posterior pituitary release amino acid-based hormones ACTH from anterior pituitary acts to cause release of steroid hormones from the adrenal cortex. Both adrenal medulla and posterior pituitary are composed of nervous tissue rather than glandular tissue, that other glands are made of

Question 77

Adrenal cortex, adrenal medulla, anterior pituitary, and posterior pituitary: which part of the glands release steroid hormones? Amino acids-based hormones?

Answer 77

Adrenal cortex released steroid hormones Adrenal medulla, anterior, and posterior pituitary release amino acid-based hormones ACTH from anterior pituitary acts to cause release of steroid hormones from the adrenal cortex. Both adrenal medulla and posterior pituitary are composed of nervous tissue rather than glandular tissue, that other glands are made of

Question 78

Insulin action on cells

Answer 78

• Activates tyrosine kinase enzyme receptor • Cascade an increased glucose uptake into increased glycogen synthesis • 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 • Also works as growth hormone, promoting: -increased amino acid uptake -to increase protein synthesis

Question 79

Insulin action on cells

Answer 79

• Activates tyrosine kinase enzyme receptor • Cascade an increased glucose uptake into increased glycogen synthesis • 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 • Also works as growth hormone, promoting: -increased amino acid uptake -to increase protein synthesis

Question 80

Pineal gland

Answer 80

-located in the diencephalon -primary hormone is melatonin which influences daily rhythm in body temp., sleep, and appetite and may have an antigonadotropic effect in children

Question 81

Pineal gland

Answer 81

-located in the diencephalon -primary hormone is melatonin which influences daily rhythm in body temp., sleep, and appetite and may have an antigonadotropic effect in children

Question 82

Factors that influence insulin release

Answer 82

• insulin release is stimulated by: -Elevated blood glucose levels – primary stimulus -Remember Insulin: Lowers blood glucose levels by driving it into cells, burning it as fuel, storing it as glycogen and fat -Rising blood levels of amino acids and fatty acids -Release of acetylcholine by parasympathetic nerve fibers (Does this make sense?) -Hyperglycemic hormones like glucagon, epinephrine, growth hormone, thyroxine, glucocorticoids -indirectly stimulate insulin release -by increasing glucose levels -Insulin release is Inhibited by: -Low blood sugar -Somatostatin (GHIH) -Secreted by Delta (d) Islet Cells -sympathetic nervous system

Question 83

Short-term stress

Answer 83

The hypothalamus activates the adrenal medulla via neural stimuli 1) APs triggered by the hypothalamus in response to stressors activate the SNS 2) APs travel along preganglionic sympathetic axons to adrenal medulla 3) adrenal medulla secrete amino acid-based hormones: epinephrine (80%) and some norepinephrine (20%) 4)epinephrine and norepinephrine reinforce other sympathetic responses to ready the body for exertion (fight or flight)

Question 84

Homeostatic imbalances of insulin

Answer 84

• Hyposecretion = Hyperglycemia -Signs and Symptoms include: -Polyuria—increased urine output with glycosuria -Glucose acts as osmotic diuretic -Polydipsia—increased thirst -From water loss due to polyuria -Polyphagia—•increased appetite (why?) -Cells cannot take up glucose; are "starving" -Since glucose can not be burned as fuel in most… -liver increases its burning of fats to generate auxiliary fuels or ketone bodies (acidic) Þketoacidosis -Untreated ketoacidosis Þ hyperpnea; disrupted heart activity and O2 transport; depression of nervous system Þ coma and death possible

Question 85

Long-term stress

Answer 85

The hypothalamus activates the adrenal cortex via hormonal stimuli. This greatly reinforces the continuing short-term stress response. 1)stressors cause hypothalamic neurons to release corticotropin-releasing hormone (CRH) 2)CRH travels via the portal system of blood vessels to the anterior pituitary 3) anterior pituitary cells (corticotrophs) release adrenocorticotropic hormone (ACTH) 4) ACTH travels in blood to the adrenal cortex 5) the adrenal cortex synthesizes and releases glucorticoids, e.g. cortisol (and Mineralocorticoids, e.g., aldosterone)

Question 86

Diabetes mellitus

Answer 86

• Group of disorders characterized by High Blood Sugar with glycosuria • Type 1 – insulin dependent –Childhood onset –beta cells do not produce insulin –May be caused by autoimmune reaction to a viral infection –Must replace insulin by multiple injections or continuous infusion •Type 2 – insulin independent –Usually later onset –Associated with obesity –beta cell produce normal amounts of insulin but cells become resistant to it –May be controlled through diet and exorcize –Oral medicines to lower blood glucose •Uncontrolled (?) Diabetes can lead to chronic medical problems

Question 87

Pancreas type of gland

Answer 87

Exocrine and endocrine. Endocrine portion (pancreatic islets) releases insulin and glucagon and smaller amounts of other hormones to the 🩸

Question 88

Hypersecretion of insulin- hyperinsulinism

Answer 88

• Causes: • –Hypoglycemia (Low blood glucose) • –Anxiety, nervousness, disorientation, unconsciousness, even death • Treated by sugar ingestion • The body cells need glucose! • NOTE: Hypoglycemia is much more serious than hyperglycemia since cells, especially neurons, can die in absence of sufficient glucose

Question 89

Pancreas: glucagon released by

Answer 89

Alpha cells when 🩸 levels of glucose are low, stimulates the liver to release glucose to the blood

Question 90

Ovaries and placenta

Answer 90

• Gonads produce steroid sex hormones – Same as those of adrenal cortex • Ovaries produce estrogens and progesterone – Estrogen -Maturation of reproductive system -Appearance of secondary sexual characteristics -With progesterone, causes breast development and cyclic changes in uterine mucosa • Placenta secretes estrogens, progesterone, and human chorionic gonadotropin (hCG)

Question 91

Pancreas: insulin is released by…

Answer 91

Beta cells when 🩸 levels of glucose (and amino acids) are rising. It increases the rate of glucose uptake and metabolism by most body cells. Hyposecretion or hyperactivity of insulin results in diabetes; cardinal signs are Polyuria, polydipsia, and polyphagia

Question 92

Pancreas: insulin is released by…

Answer 92

Beta cells when 🩸 levels of glucose (and amino acids) are rising. It increases the rate of glucose uptake and metabolism by most body cells. Hyposecretion or hyperactivity of insulin results in diabetes; cardinal signs are Polyuria, polydipsia, and polyphagia

Question 93

Testes

Answer 93

• Testes produce testosterone -initiates maturation of male reproductive organs -Causes appearance of male secondary sexual characteristics and sex drive -Necessary for normal sperm production -Maintains reproductive organs in functional state

Question 94

Adipose tissue

Answer 94

Leptin – appetite control; stimulates increased energy expenditure

Question 95

Thymus

Answer 95

-Located: upper thorax -releases the paracrines thymulin, thymosins, and thymopoietins, which are important tissues the normal development of the immune response

Question 96

Enteroendocrine cells of GI

Answer 96

• Gastrin stimulates release of HCl • Secretin stimulates liver and pancreas • Cholecystokinin stimulates pancreas, gallbladder, and hepatopancreatic sphincter • Serotonin acts as paracrine

Question 97

Enteroendocrine cells of GI

Answer 97

• Gastrin stimulates release of HCl • Secretin stimulates liver and pancreas • Cholecystokinin stimulates pancreas, gallbladder, and hepatopancreatic sphincter • Serotonin acts as paracrine

Question 98

❤️

Answer 98

Atrial natriuretic peptide (ANP) decreases blood Na+ concentration, therefore blood pressure and blood volume

Question 99

Kidneys

Answer 99

• Erythropoietin signals production of red blood cells • Renin initiates the renin-angiotensin-aldosterone mechanism

Question 100

Kidneys

Answer 100

• Erythropoietin signals production of red blood cells • Renin initiates the renin-angiotensin-aldosterone mechanism

Question 101

Skeleton (osteoblasts)

Answer 101

Osteocalcin • Prods pancreas to secrete more insulin; restricts fat storage; improves glucose handling; reduces body fat • Activated by insulin • Low levels of osteocalcin in type 2 diabetes – perhaps increasing levels may be new treatment

Question 102

Skin

Answer 102

Cholecalciferol, precursor of vitamin D

Question 103

Skin

Answer 103

Cholecalciferol, precursor of vitamin D

Question 104

Which hormones does ❤️ produce and what is its function?

Answer 104

The ❤️ produces atrial natriuretic (ANP). ANP decreases 🩸pressure by increasing the kidney’s production of salty urine

Question 105

What is the main function of the hormone produced by the skin?

Answer 105

Major function of vit D3, produced in inactive form by the skin, is to increase intestinal absorption of calcium

Question 106

Diabetes mellitus and diabetes inspidus are both due to a lack of a hormone. Which hormone causes which? What symptom do they have in common? What would you find in the urine of a pt w/ 1 but not the other.

Answer 106

Diabetes mellitus is due to a lack of insulin production or action, whereas diabetes inspidus is due to lack of ADH. Both conditions are characterized by production of copious amounts of urine. You would find glucose in the urine of a pt with diabetes mellitus, but not in diabetes inspidus

Question 107

What chemical class of hormones do gonadal hormones belong to? Which major endocrine gland secretes hormones of the same chemical class

Answer 107

Gonadal hormones are steroid hormones. A major endocrine that also secretes steroid hormones is the adrenal cortex

Question 108

The major stimulus for release of parathyroid hormone is…

Answer 108

Humoral

Question 109

Important anabolic hormones; many of its effects mediated by IGFs

Answer 109

Growth hormone

Question 110

Cause the kidneys to conserve water and/or salt

Answer 110

Aldosterone and ADH

Question 111

Stimulates milk production

Answer 111

Prolactin

Question 112

Tropic hormone that stimulates the gonads to secrete sex hormones

Answer 112

LH

Question 113

Increases uterine contractions during birth

Answer 113

Oxytocin

Question 114

Major metabolic hormones of the body

Answer 114

T4 and T3

Question 115

Causes reabsorption of sodium ions by the kidneys

Answer 115

Aldosterone

Question 116

Causes reabsorption of sodium ions by the kidneys

Answer 116

Aldosterone

Question 117

Tropic hormone that stimulates the thyroid gland to secrete thyroid hormone

Answer 117

TSH

Question 118

Secreted by posterior pituitary

Answer 118

ADH and oxytocin

Question 119

Steroid hormone

Answer 119

Aldosterone

Question 120

If there is adequate carb intake, secretion of insulin results in…

Answer 120

-lower 🩸 glucose -increased cell utilization of glucose -storage of glycogen

Question 121

If there is adequate carb intake, secretion of insulin results in…

Answer 121

-lower 🩸 glucose -increased cell utilization of glucose -storage of glycogen

Question 122

If anterior pituitary secretion is deficient in a growing child, the child will…

Answer 122

Become a dwarf but have fairly normal body proportions

Question 123

Some hormones act by

Answer 123

-increasing the synthesis of enzymes -converting an inactive enzyme into an active enzyme -affecting only specific target organs

Question 124

Lipolysis

Answer 124

metabolic process that breaks down fat stores in the body into glycerol and free fatty acids (FFAs)

Question 125

Gluconeogenesis

Answer 125

Metabolic process that produces glucose from non-carb sources, such as amino acids, lactate, and glycerol

Question 126

Glycogenolysis

Answer 126

process of breaking down glycogen into glucose to produce energy when the body needs it

Question 127

What is the mechanism of action of lipid-soluble hormones?

Answer 127

Activation of genes, which increases protein synthesis in the cell

Question 128

What keeps intracellukar receptors from binding to DNA before a hormone binds to the receptor?

Answer 128

Chaperone proteins (chaperonins)

Question 129

What gland secretes the most important hormone controlling calcium balance in the blood?

Answer 129

Parathyroid

Question 130

Zona glomerulosa: class of hormones it produces

Answer 130

Mineralocorticoids

Question 131

What material is stored in the lumen of thyroid follicle?

Answer 131

Iodinated thyroglobulin, from which TH can be produced

Question 132

What type of stimulation controls parathyroid release?

Answer 132

Humoral

Question 133

Another name for TSH

Answer 133

Thyroidtropin