logging in or signing up Endorcrine System 2 rangerblue Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 428 Category: Entertainment License: All Rights Reserved Like it (1) Dislike it (0) Added: November 05, 2009 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... By: mia_ql (21 month(s) ago) thank you sooo much! Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript Endocrine System : Endocrine System The Classical Endocrine System : The Classical Endocrine System Pineal gland Hypothalamus / Pituitary Thyroid Parathyroid Thymus Adrenal glands Pancreas Gonads Other Endocrine Organs : Other Endocrine Organs Stomach - releases gastrin from G-cells Duodenum – CCK, secretin Heart – ANP Kidney – renin, erythropoietin Placenta - hCG Endocrine System Function : Endocrine System Function Maintenance of homeostasis through negative feedback loops Endocrine System Function : Endocrine System Function Communication between organ systems within the body (like nervous system) Differs from the nervous system: changes take longer to occur and changes persist longer as well. Endocrine System Function : Endocrine System Function Hormones are utilized as chemical messengers Messages are received by target cells Hormones : Hormones Recall the distinction between exocrine and endocrine glands Exocrine: through a duct Endocrine: into the blood Hormones : Hormones Endocrine hormones are transmitted in the bloodstream to all parts of the body Hormones only have an effect on those cells that have a hormone receptor embedded in the cell membrane (target cells) 2 types of endocrine hormones: steroid & non-steroid Hormones : Hormones Hormones : Hormones Steroid Hormones : Steroid Hormones Slower, longer lasting effect than non-steroid hormones Derived form cholesterol Lipid soluble, need to be transported in the bloodstream combined with a transport protein Steroid Hormones : Steroid Hormones Mainly from the adrenal cortex and/or gonads Mineralocoritcoid → aldosterone Glucocorticoids → cortisol, cortisone Sex steroids → progestin, estrogens, androgens Non-steroid Hormones : Non-steroid Hormones Water soluble – most are transported freely in the blood Cascade of reactions within the cell “amplifies” the signal This type of hormone causes a more rapid onset and shorter duration of the effect than steroid hormones Non-steroid Hormones : Non-steroid Hormones Types of Non-steroid hormones Protein (polypeptide) – insulin, growth hormone, FSH Glycoprotein – LH, TSH Oligopeptide – ADH, oxytocin Amine –norepinephrine, epinephrine, dopamine (neurotransmitters) Paracrine Hormones : Paracrine Hormones Do not enter the general circulation Communication from cell to cell within a specific tissue Very low levels in the blood Have little or no effect in distant tissue Example: prostaglandins Pituitary : Pituitary Interacts with many (not all) endocrine glands as part of a feedback loop between the hypothalamus and the respective gland. Pituitary : Pituitary The pituitary serves as a link between the CNS (hypothalamus) and the rest of the endocrine system Pituitary : Pituitary The pituitary is suspended from a stalk (infundibulum) attached to the hypothalamus and enclosed within the sella turcica (sphenoid bone) Pituitary : Pituitary Actually 2 separate glands: anterior pituitary & posterior pituitary No blood brain barrier in the hypothalamus Anterior Pituitary : Anterior Pituitary The releasing hormone is secreted into a portal system Cells in the anterior pituitary are stimulated to secrete another hormone Posterior Pituitary : Posterior Pituitary Neurons from the hypothalamus enter the posterior pituitary and stimulate cells to secrete hormones Anterior Pituitary : Anterior Pituitary Note: GH is also called somatotropin There are also inhibitory factors from the hypothalamus for GH and PRL Posterior Pituitary : Posterior Pituitary * failure of the posterior pituitary to secrete ADH results in Diabetes Insipidus (DI)……if no ADH is produced the result is production of LARGE volumes of dilute urine Growth Hormone : Growth Hormone GHRH/somatostatin GH or somatotropin cells related to body growth Produced in the ant. Pituitary Secretion declines gradually with age Many more GH producing cells in ant. pituitary than any other type Growth Hormone : Growth Hormone Increased cell division (mitosis) & increased cell growth & differentiation The main effects are on cartilage, muscle, bone, fat Promotes protein synthesis (transcription/translation) Anti-insulin effect - elevates blood sugar Growth Hormone : Growth Hormone Catabolism of fat for energy instead of glucose Muscle & bone are effected indirectly through Insulin like Growth Factor (IGF-1) increased muscle mass, bone lengthening and decreased fat tissue Growth Hormone : Growth Hormone Continued secretion of high levels after epiphysial plate closure is called acromegaly Bones continue to thicken even after epiphysial plate closure Growth Hormone : Growth Hormone Acromegaly is usually related to a pituitary tumor Prolactin : Prolactin More PRF/and less PIF from the hypothalamus Causes PRL secretion from the ant. Pituitary Effects the mammary gland in women/testes in men Prolactin : Prolactin In women increased levels during pregnancy after delivery causes mammary glands to produce milk In men increases sensitivity to LH and indirectly enhances testosterone production Thyroid Gland : Thyroid Gland TRH (hypothalamus) → TSH (pituitary) → Thyroid hormone (Thyroid gland) Thyroid Gland : Thyroid Gland 2 lobes, on either side of the trachea, connected by an isthmus Thyroid Gland : Thyroid Gland Microscopic anatomy Thyroid follicles, lined by secretory epithelium (follicular cells) Filled with thyroglobulin (transport protein) Parafollicular cells between the follicles Thyroid Function : Thyroid Function Secretes two hormones (both require iodine as a precursor) Thyroxine (T4) & Triiodothyronine (T3) Thyroid Function : Thyroid Function (T4): 90% of all Thyroid hormone Less active Converted to T3 in the cell Most remains in the bloodstream as reservoir of thyroid hormone Thyroid Function : Thyroid Function (T3): 5 times more metabolically active, but only 10% of total hormone that is produced Thyroid Function : Thyroid Function Mitochondria: increased cellular respiration Ribosomes: increased protein synthesis Chromatin: increased transcription DNA to mRNA Binds to three sites in the cell Hyperthyroidism : Hyperthyroidism Thyroid hormones promote cellular respiration Cellular respiration requires oxygen, therefore heart rate & respiratory rate are increased Produces heat; causes sweating Higher metabolic rate requires more calories, which is a stimulus for hunger Graves Disease : Graves Disease The most common form of hyperthyroidism (autoimmune) Signs and symptoms may include heat intolerance, appetite, weight loss, warm moist skin, nervousness, tremor, BP, tachycardia, goiter, exophthalmos Exophthalmos may be due to an autoimmune, inflammatory reaction in the soft tissue that is confined within the boney orbit Endemic Goiter : Endemic Goiter A goiter is an enlarged thyroid gland Endemic goiter is due to lack of iodine in the diet No thyroid hormone is produced so there is no negative feedback The thyroid gland hypertrophies as it “tries” to make more thyroid hormone Hypothyroidism : Hypothyroidism In children (cretinism) permanent mental retardation due to inadequate nervous system development In adults common cause of fatigue other symptoms are related to low BMR cold intolerance, weight gain, CNS function (mentation), BP, dry skin Adrenal Glands : Adrenal Glands Each gland is actually 2 separate glands: the cortex & medulla Adrenal Functions : Adrenal Functions Adrenal Medulla : Adrenal Medulla Secretes Catecholamines (Epinephrine & Norepinephrine) Derived from SNS neurons (Chromaffin cells) that lack dendrites & axons Adrenal Medulla : Adrenal Medulla Innervated by SNS Secretes SNS neurotransmitters mostly Epinephrine (Adrenalin) The presence of these neurotransmitters in the circulation lowers the threshold for transmission of an impulse in the SNS for about 30 min. Epinephrine : Epinephrine Elevates blood sugar – glucose sparing effects to preserve glucose for the CNS glycogenolysis gluconeogenesis Adrenal Cortex : Adrenal Cortex 3 layers Adrenal Cortex : Adrenal Cortex Slide 49: Aldosterone – Na+ retention/ K+ secretion Water follows Sodium, so fluid volume and BP increase too Recall that aldosterone secretion can be promoted by: ACTH Angiotensin II Low Na+ High K+ Adrenal Cortex: Z. Glomerulosa Slide 50: Secretes Cortisol (hydrocortisone) Corticosterone and cortisone are two other similar hormones that are secreted Steroid medication can suppress adrenal function Adrenal Cortex: Z. Fasciculata Slide 51: Two basic effects of Cortisol: Glucose sparing effects: increased glucose synthesis & protein/lipid catabolism (gluconeogenesis) Anti-inflammatory effects: inhibits WBC function, decreased phagocytosis, decreased chemotaxis, decreased mast cell degranulation Adrenal Cortex: Z. Fasciculata Adrenal Cortex: Z. Reticularis : Adrenal Cortex: Z. Reticularis Sex steroids – small amount of estrogens & weak androgens (DHEA), which is a precursor of testosterone Testosterone is required in men & women – pubic & axillary hair, libido, apocrine sweat glands most testosterone is produced in testes in men 50% produced by the adrenal gland in women Cushing’s Disease : Cushing’s Disease Hyperfunction of the Adrenal glands Disrupts normal carbohydrate & protein metabolism (Cortisol) characteristic lipid deposits in the face Potential electrolyte imbalance (Aldosterone) Mood changes (Testosterone) Gonads : Gonads Ovaries Secrete estrogen & progesterone during the menstrual cycle FSH from the pituitary causes maturation of the follicle & egg LH causes ovulation (rupture of the follicle – release of the egg) Testes FSH promotes spermatogenesis LH causes interstitial cells to secrete testosterone Testosterone from adrenal gland is also present in women, but at much lower levels Produces secondary sexual characteristics in men Parathyroid Glands : Parathyroid Glands Not linked to the hypothalamic-pituitary axis 4 small nodules of tissue in the thyroid gland Parathyroid Glands : Parathyroid Glands PTH is secreted in response to low serum Ca++ (hypocalcemia) Promotes synthesis of calcitrol (active metabolite of vitamin D), which ↑ GI absorption of Ca++ Limits Ca++ secretion by the kidney Stimulates osteoclasts to reabsorb bone Slide 57: PTH is opposed by the action of calcitonin Secreted in response to elevated Ca++ (hypercalcemia) by parafollicular (C-cells) of the thyroid gland Little effect in adults Stimulates mineral deposition in bone by osteoblasts Parathyroid Glands Pancreas : Pancreas Not linked to hypothalamic pituitary axis Both exocrine & endocrine functions Pancreas : Pancreas Endocrine hormones: insulin & glucagon secreted by cells in the islets of Langerhans Glucagon : Glucagon Alpha cells secrete glucagon Glucagon is secreted in response to low blood sugar, causing glycogen to be converted to glucose (glycogenolysis) Insulin : Insulin Beta cells secrete insulin insulin is secreted in response to ↑ blood sugar, causes ↑ permeability of cell membranes throughout the body to glucose Except CNS...does not require insulin to take up glucose Diabetes Mellitus : Diabetes Mellitus Elevated blood sugar Normal fasting blood sugar is 70 – 100 mg/dL 100 – 125 mg/dL is “prediabetic” Higher than 125 mg/dL is either Type I or Type II diabetes Type I Diabetes Mellitus : Type I Diabetes Mellitus A failure of beta cells to produce insulin Also called IDDM (Insulin Dependent DM) complete loss of insulin means that replacement is required Usually onset is in childhood (juvenile onset) Type I Diabetes Mellitus : Type I Diabetes Mellitus Abrupt onset of symptoms DKA (diabetic ketoacidosis) No glucose is available to cells They utilize lipids instead This produces ketoacids (lower the pH) Polydipsia (thirst) Polyphagia (hunger) Polyuria (osmotic diuresis) Slide 65: The renal threshold for glucose resorption is exceeded resulting in glycosuria Poorly controlled DM is a disease of small blood vessels diabetic nephropathy diabetic retinopathy diabetic neuropathy changes in coronary & peripheral vessels increase the risk of vascular disease Type I Diabetes Mellitus Diabetes Mellitus type II : Diabetes Mellitus type II An insensitivity of an insulin receptor in cell membranes to insulin NIDDM (Non Insulin Dependent DM) usually does not require insulin (oral hypoglycemics) Usually onset is as an adult Onset is insidious Usually no ketoacidosis Diabetes Mellitus : Diabetes Mellitus Long term monitoring of blood sugar levels (months) Hgb A1C (glycosylated hemoglobin) A type of hgb that incorporates a sugar molecule More Hgb A1C is made when blood sugar levels are high Pineal gland : Pineal gland The main hormone is melatonin The precursor is a CNS neurotransmitter, serotonin Pineal gland : Pineal gland Production and secretion of melatonin is stimulated by darkness Information about light levels is provided through the retina in mammals Pineal gland : Pineal gland Circadian rhythm Regulates sleep / wake cycle Undergoes involution during childhood, which may bring about the onset of puberty Near the skin in non-mammal vertebrates Light levels are perceived directly Regulates seasonal behavior in other animals Migratory patterns in birds Breeding cycles in animals with seasonal reproductive patterns Thymus : Thymus Posterior to the sternum Larger in adolescence Regresses at puberty Secretes thymosin Thymus : Thymus Thymosin causes undifferentiated lymphocytes to become T cells Blood – thymus barrier in the cortex Only T cells that are “self tolerant” are released to the medulla and into the rest of the body cortex medulla Stress : Stress A stressor is a stimulus to promote a response to a threatening situation Stress : Stress 3 phases of the stress response The alarm phase Resistance phase: occurs as glycogen is consumed Exhaustion phase: chronic stress occurs over a period of weeks Slide 75: An immediate response Increased sympathetic output (fight or flight) The adrenal medulla secretes catecholamines like adrenalin (SNS neurotransmitter) Stress: The Alarm Phase Slide 76: SNS input to the kidney initiates the RAA cascade which leads to : Increased BP to supply large skeletal muscles Increased fluid retention to compensate for potential fluid loss through sweat or hemorrhage Glycogen stores are consumed in a few hours Stress: The Alarm Phase Slide 77: Occurs as glycogen is consumed: Hypothalamus → CRH → ACTH → Cortisol Stress: The Resistance Phase Slide 78: Cortisol decreases glucose use peripherally (glucose sparing for the CNS) Promotes the breakdown of protein & fatty acids, which are converted to glucose in the liver (gluconeogenesis) Stress: The Resistance Phase Slide 79: Both Adrenaline (alarm phase) and Cortisol (resistance phase) elevate blood sugar Stress and Blood Sugar Stress: The Exhaustion Phase : Stress: The Exhaustion Phase Chronic stress occurs over a period of weeks: Less protein is available for immune system function (gluconeogenesis) ↓ ability to make antibodies (protein) ↑ susceptibility to infections ↓ protein available for wound healing Paracrine Secretions : Paracrine Secretions Paracrine hormones exert a local effect Eicosanoids are paracrine secretions They are produced by the Arachidonic acid pathway Slide 82: Arachidonic acid (a fatty acid) is produced from phospholipids in the cell membrane This reaction is catalyzed by phospholipase A2 Arachidonic Acid Pathway Slide 83: Arachidonic acid is then subjected to either of two metabolic pathways lipoxygenase – leads to the production of leukotrienes, chemical mediators of inflammation Arachidonic Acid Pathway Slide 84: cyclooxygenase – leads to the production of prostaglandins, thromboxane, and prostacyclin Arachidonic Acid Pathway Paracrine Secretions : Paracrine Secretions Thromboxane is secreted by platelets to enhance platelet aggregation Prostaglandins have many effects depending upon the specific metabolite fever pain etc. Paracrine Secretions : Paracrine Secretions Steroid medication (e.g. cortisol/prednisone) blocks the production of arachidonic acid (phosphlipase) *Non-steroidal anti-inflammatories (NSAID’s) like aspirin and Ibuprofen block the cyclooxygenase pathway to reduce inflammation & fever You do not have the permission to view this presentation. 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Endorcrine System 2 rangerblue Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 428 Category: Entertainment License: All Rights Reserved Like it (1) Dislike it (0) Added: November 05, 2009 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... By: mia_ql (21 month(s) ago) thank you sooo much! Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript Endocrine System : Endocrine System The Classical Endocrine System : The Classical Endocrine System Pineal gland Hypothalamus / Pituitary Thyroid Parathyroid Thymus Adrenal glands Pancreas Gonads Other Endocrine Organs : Other Endocrine Organs Stomach - releases gastrin from G-cells Duodenum – CCK, secretin Heart – ANP Kidney – renin, erythropoietin Placenta - hCG Endocrine System Function : Endocrine System Function Maintenance of homeostasis through negative feedback loops Endocrine System Function : Endocrine System Function Communication between organ systems within the body (like nervous system) Differs from the nervous system: changes take longer to occur and changes persist longer as well. Endocrine System Function : Endocrine System Function Hormones are utilized as chemical messengers Messages are received by target cells Hormones : Hormones Recall the distinction between exocrine and endocrine glands Exocrine: through a duct Endocrine: into the blood Hormones : Hormones Endocrine hormones are transmitted in the bloodstream to all parts of the body Hormones only have an effect on those cells that have a hormone receptor embedded in the cell membrane (target cells) 2 types of endocrine hormones: steroid & non-steroid Hormones : Hormones Hormones : Hormones Steroid Hormones : Steroid Hormones Slower, longer lasting effect than non-steroid hormones Derived form cholesterol Lipid soluble, need to be transported in the bloodstream combined with a transport protein Steroid Hormones : Steroid Hormones Mainly from the adrenal cortex and/or gonads Mineralocoritcoid → aldosterone Glucocorticoids → cortisol, cortisone Sex steroids → progestin, estrogens, androgens Non-steroid Hormones : Non-steroid Hormones Water soluble – most are transported freely in the blood Cascade of reactions within the cell “amplifies” the signal This type of hormone causes a more rapid onset and shorter duration of the effect than steroid hormones Non-steroid Hormones : Non-steroid Hormones Types of Non-steroid hormones Protein (polypeptide) – insulin, growth hormone, FSH Glycoprotein – LH, TSH Oligopeptide – ADH, oxytocin Amine –norepinephrine, epinephrine, dopamine (neurotransmitters) Paracrine Hormones : Paracrine Hormones Do not enter the general circulation Communication from cell to cell within a specific tissue Very low levels in the blood Have little or no effect in distant tissue Example: prostaglandins Pituitary : Pituitary Interacts with many (not all) endocrine glands as part of a feedback loop between the hypothalamus and the respective gland. Pituitary : Pituitary The pituitary serves as a link between the CNS (hypothalamus) and the rest of the endocrine system Pituitary : Pituitary The pituitary is suspended from a stalk (infundibulum) attached to the hypothalamus and enclosed within the sella turcica (sphenoid bone) Pituitary : Pituitary Actually 2 separate glands: anterior pituitary & posterior pituitary No blood brain barrier in the hypothalamus Anterior Pituitary : Anterior Pituitary The releasing hormone is secreted into a portal system Cells in the anterior pituitary are stimulated to secrete another hormone Posterior Pituitary : Posterior Pituitary Neurons from the hypothalamus enter the posterior pituitary and stimulate cells to secrete hormones Anterior Pituitary : Anterior Pituitary Note: GH is also called somatotropin There are also inhibitory factors from the hypothalamus for GH and PRL Posterior Pituitary : Posterior Pituitary * failure of the posterior pituitary to secrete ADH results in Diabetes Insipidus (DI)……if no ADH is produced the result is production of LARGE volumes of dilute urine Growth Hormone : Growth Hormone GHRH/somatostatin GH or somatotropin cells related to body growth Produced in the ant. Pituitary Secretion declines gradually with age Many more GH producing cells in ant. pituitary than any other type Growth Hormone : Growth Hormone Increased cell division (mitosis) & increased cell growth & differentiation The main effects are on cartilage, muscle, bone, fat Promotes protein synthesis (transcription/translation) Anti-insulin effect - elevates blood sugar Growth Hormone : Growth Hormone Catabolism of fat for energy instead of glucose Muscle & bone are effected indirectly through Insulin like Growth Factor (IGF-1) increased muscle mass, bone lengthening and decreased fat tissue Growth Hormone : Growth Hormone Continued secretion of high levels after epiphysial plate closure is called acromegaly Bones continue to thicken even after epiphysial plate closure Growth Hormone : Growth Hormone Acromegaly is usually related to a pituitary tumor Prolactin : Prolactin More PRF/and less PIF from the hypothalamus Causes PRL secretion from the ant. Pituitary Effects the mammary gland in women/testes in men Prolactin : Prolactin In women increased levels during pregnancy after delivery causes mammary glands to produce milk In men increases sensitivity to LH and indirectly enhances testosterone production Thyroid Gland : Thyroid Gland TRH (hypothalamus) → TSH (pituitary) → Thyroid hormone (Thyroid gland) Thyroid Gland : Thyroid Gland 2 lobes, on either side of the trachea, connected by an isthmus Thyroid Gland : Thyroid Gland Microscopic anatomy Thyroid follicles, lined by secretory epithelium (follicular cells) Filled with thyroglobulin (transport protein) Parafollicular cells between the follicles Thyroid Function : Thyroid Function Secretes two hormones (both require iodine as a precursor) Thyroxine (T4) & Triiodothyronine (T3) Thyroid Function : Thyroid Function (T4): 90% of all Thyroid hormone Less active Converted to T3 in the cell Most remains in the bloodstream as reservoir of thyroid hormone Thyroid Function : Thyroid Function (T3): 5 times more metabolically active, but only 10% of total hormone that is produced Thyroid Function : Thyroid Function Mitochondria: increased cellular respiration Ribosomes: increased protein synthesis Chromatin: increased transcription DNA to mRNA Binds to three sites in the cell Hyperthyroidism : Hyperthyroidism Thyroid hormones promote cellular respiration Cellular respiration requires oxygen, therefore heart rate & respiratory rate are increased Produces heat; causes sweating Higher metabolic rate requires more calories, which is a stimulus for hunger Graves Disease : Graves Disease The most common form of hyperthyroidism (autoimmune) Signs and symptoms may include heat intolerance, appetite, weight loss, warm moist skin, nervousness, tremor, BP, tachycardia, goiter, exophthalmos Exophthalmos may be due to an autoimmune, inflammatory reaction in the soft tissue that is confined within the boney orbit Endemic Goiter : Endemic Goiter A goiter is an enlarged thyroid gland Endemic goiter is due to lack of iodine in the diet No thyroid hormone is produced so there is no negative feedback The thyroid gland hypertrophies as it “tries” to make more thyroid hormone Hypothyroidism : Hypothyroidism In children (cretinism) permanent mental retardation due to inadequate nervous system development In adults common cause of fatigue other symptoms are related to low BMR cold intolerance, weight gain, CNS function (mentation), BP, dry skin Adrenal Glands : Adrenal Glands Each gland is actually 2 separate glands: the cortex & medulla Adrenal Functions : Adrenal Functions Adrenal Medulla : Adrenal Medulla Secretes Catecholamines (Epinephrine & Norepinephrine) Derived from SNS neurons (Chromaffin cells) that lack dendrites & axons Adrenal Medulla : Adrenal Medulla Innervated by SNS Secretes SNS neurotransmitters mostly Epinephrine (Adrenalin) The presence of these neurotransmitters in the circulation lowers the threshold for transmission of an impulse in the SNS for about 30 min. Epinephrine : Epinephrine Elevates blood sugar – glucose sparing effects to preserve glucose for the CNS glycogenolysis gluconeogenesis Adrenal Cortex : Adrenal Cortex 3 layers Adrenal Cortex : Adrenal Cortex Slide 49: Aldosterone – Na+ retention/ K+ secretion Water follows Sodium, so fluid volume and BP increase too Recall that aldosterone secretion can be promoted by: ACTH Angiotensin II Low Na+ High K+ Adrenal Cortex: Z. Glomerulosa Slide 50: Secretes Cortisol (hydrocortisone) Corticosterone and cortisone are two other similar hormones that are secreted Steroid medication can suppress adrenal function Adrenal Cortex: Z. Fasciculata Slide 51: Two basic effects of Cortisol: Glucose sparing effects: increased glucose synthesis & protein/lipid catabolism (gluconeogenesis) Anti-inflammatory effects: inhibits WBC function, decreased phagocytosis, decreased chemotaxis, decreased mast cell degranulation Adrenal Cortex: Z. Fasciculata Adrenal Cortex: Z. Reticularis : Adrenal Cortex: Z. Reticularis Sex steroids – small amount of estrogens & weak androgens (DHEA), which is a precursor of testosterone Testosterone is required in men & women – pubic & axillary hair, libido, apocrine sweat glands most testosterone is produced in testes in men 50% produced by the adrenal gland in women Cushing’s Disease : Cushing’s Disease Hyperfunction of the Adrenal glands Disrupts normal carbohydrate & protein metabolism (Cortisol) characteristic lipid deposits in the face Potential electrolyte imbalance (Aldosterone) Mood changes (Testosterone) Gonads : Gonads Ovaries Secrete estrogen & progesterone during the menstrual cycle FSH from the pituitary causes maturation of the follicle & egg LH causes ovulation (rupture of the follicle – release of the egg) Testes FSH promotes spermatogenesis LH causes interstitial cells to secrete testosterone Testosterone from adrenal gland is also present in women, but at much lower levels Produces secondary sexual characteristics in men Parathyroid Glands : Parathyroid Glands Not linked to the hypothalamic-pituitary axis 4 small nodules of tissue in the thyroid gland Parathyroid Glands : Parathyroid Glands PTH is secreted in response to low serum Ca++ (hypocalcemia) Promotes synthesis of calcitrol (active metabolite of vitamin D), which ↑ GI absorption of Ca++ Limits Ca++ secretion by the kidney Stimulates osteoclasts to reabsorb bone Slide 57: PTH is opposed by the action of calcitonin Secreted in response to elevated Ca++ (hypercalcemia) by parafollicular (C-cells) of the thyroid gland Little effect in adults Stimulates mineral deposition in bone by osteoblasts Parathyroid Glands Pancreas : Pancreas Not linked to hypothalamic pituitary axis Both exocrine & endocrine functions Pancreas : Pancreas Endocrine hormones: insulin & glucagon secreted by cells in the islets of Langerhans Glucagon : Glucagon Alpha cells secrete glucagon Glucagon is secreted in response to low blood sugar, causing glycogen to be converted to glucose (glycogenolysis) Insulin : Insulin Beta cells secrete insulin insulin is secreted in response to ↑ blood sugar, causes ↑ permeability of cell membranes throughout the body to glucose Except CNS...does not require insulin to take up glucose Diabetes Mellitus : Diabetes Mellitus Elevated blood sugar Normal fasting blood sugar is 70 – 100 mg/dL 100 – 125 mg/dL is “prediabetic” Higher than 125 mg/dL is either Type I or Type II diabetes Type I Diabetes Mellitus : Type I Diabetes Mellitus A failure of beta cells to produce insulin Also called IDDM (Insulin Dependent DM) complete loss of insulin means that replacement is required Usually onset is in childhood (juvenile onset) Type I Diabetes Mellitus : Type I Diabetes Mellitus Abrupt onset of symptoms DKA (diabetic ketoacidosis) No glucose is available to cells They utilize lipids instead This produces ketoacids (lower the pH) Polydipsia (thirst) Polyphagia (hunger) Polyuria (osmotic diuresis) Slide 65: The renal threshold for glucose resorption is exceeded resulting in glycosuria Poorly controlled DM is a disease of small blood vessels diabetic nephropathy diabetic retinopathy diabetic neuropathy changes in coronary & peripheral vessels increase the risk of vascular disease Type I Diabetes Mellitus Diabetes Mellitus type II : Diabetes Mellitus type II An insensitivity of an insulin receptor in cell membranes to insulin NIDDM (Non Insulin Dependent DM) usually does not require insulin (oral hypoglycemics) Usually onset is as an adult Onset is insidious Usually no ketoacidosis Diabetes Mellitus : Diabetes Mellitus Long term monitoring of blood sugar levels (months) Hgb A1C (glycosylated hemoglobin) A type of hgb that incorporates a sugar molecule More Hgb A1C is made when blood sugar levels are high Pineal gland : Pineal gland The main hormone is melatonin The precursor is a CNS neurotransmitter, serotonin Pineal gland : Pineal gland Production and secretion of melatonin is stimulated by darkness Information about light levels is provided through the retina in mammals Pineal gland : Pineal gland Circadian rhythm Regulates sleep / wake cycle Undergoes involution during childhood, which may bring about the onset of puberty Near the skin in non-mammal vertebrates Light levels are perceived directly Regulates seasonal behavior in other animals Migratory patterns in birds Breeding cycles in animals with seasonal reproductive patterns Thymus : Thymus Posterior to the sternum Larger in adolescence Regresses at puberty Secretes thymosin Thymus : Thymus Thymosin causes undifferentiated lymphocytes to become T cells Blood – thymus barrier in the cortex Only T cells that are “self tolerant” are released to the medulla and into the rest of the body cortex medulla Stress : Stress A stressor is a stimulus to promote a response to a threatening situation Stress : Stress 3 phases of the stress response The alarm phase Resistance phase: occurs as glycogen is consumed Exhaustion phase: chronic stress occurs over a period of weeks Slide 75: An immediate response Increased sympathetic output (fight or flight) The adrenal medulla secretes catecholamines like adrenalin (SNS neurotransmitter) Stress: The Alarm Phase Slide 76: SNS input to the kidney initiates the RAA cascade which leads to : Increased BP to supply large skeletal muscles Increased fluid retention to compensate for potential fluid loss through sweat or hemorrhage Glycogen stores are consumed in a few hours Stress: The Alarm Phase Slide 77: Occurs as glycogen is consumed: Hypothalamus → CRH → ACTH → Cortisol Stress: The Resistance Phase Slide 78: Cortisol decreases glucose use peripherally (glucose sparing for the CNS) Promotes the breakdown of protein & fatty acids, which are converted to glucose in the liver (gluconeogenesis) Stress: The Resistance Phase Slide 79: Both Adrenaline (alarm phase) and Cortisol (resistance phase) elevate blood sugar Stress and Blood Sugar Stress: The Exhaustion Phase : Stress: The Exhaustion Phase Chronic stress occurs over a period of weeks: Less protein is available for immune system function (gluconeogenesis) ↓ ability to make antibodies (protein) ↑ susceptibility to infections ↓ protein available for wound healing Paracrine Secretions : Paracrine Secretions Paracrine hormones exert a local effect Eicosanoids are paracrine secretions They are produced by the Arachidonic acid pathway Slide 82: Arachidonic acid (a fatty acid) is produced from phospholipids in the cell membrane This reaction is catalyzed by phospholipase A2 Arachidonic Acid Pathway Slide 83: Arachidonic acid is then subjected to either of two metabolic pathways lipoxygenase – leads to the production of leukotrienes, chemical mediators of inflammation Arachidonic Acid Pathway Slide 84: cyclooxygenase – leads to the production of prostaglandins, thromboxane, and prostacyclin Arachidonic Acid Pathway Paracrine Secretions : Paracrine Secretions Thromboxane is secreted by platelets to enhance platelet aggregation Prostaglandins have many effects depending upon the specific metabolite fever pain etc. Paracrine Secretions : Paracrine Secretions Steroid medication (e.g. cortisol/prednisone) blocks the production of arachidonic acid (phosphlipase) *Non-steroidal anti-inflammatories (NSAID’s) like aspirin and Ibuprofen block the cyclooxygenase pathway to reduce inflammation & fever