The Endocrine System

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The Endocrine System
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Endocrine System

• Endocrine vs. Exocrine
• Organs are not physically connected
• Alters activities of target organs/cells
• Purpose Growth/Development
• Reproduction
• Regulation
• Stress Reactions

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Hormones are Activated By

• Hormonal
• Humoral
• Neural

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Gland/Hormone Functions

• Some glands produce gt1 hormone
• Some hormones produced by gt1 gland
• Some organs have gt1 function
• Some hormones have gt1 function

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Functions of Endocrine Glands

• Endocrine Functions only
• Production
• Secretion
• Contained within other organs which have other
  functions

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Categories of Glands

• Central Pituitary
• Hypothalamus
• Peripheral Thyroid Pineal
• Adrenals Gonads
• Parathyroids Pancreas
• Thymus Others

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Hypothalamus

• Found on floor of diencephalon
• Neural and endocrine functions
• Biofeedback mechanism for
• Osmotic pressures
• Temperature regulations
• Metabolic functions

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Pituitary

• Extends from Hypothalamus-behind sphenoid bone
• Master Gland of body
• Anterior- Portal network
• Posterior- Neural-contains axons of
• Hypothalamus neurons

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Anterior Pituitary

• GH- Growth Hormone
• Prolactin
• TSH- Thyroid Stimulating Hormone
• ACTH- Adrenocorticotropic
• FSH- Follicle Stimulating Hormone
• LH- Luteinizing Hormone

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Posterior Pituitary

• ADH- Anti-Diuretic Hormone
• Oxytocin

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Pituitary Disorders

• Acromegaly- Hypersecretion of GH
• Dwarfism- Hyposecretion of GH

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Thyroid

• Inferior to larynx
• 2 Lobes
• T3- Triiodothyronine
• T4- Thyroxine
• Calcitonin

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Thyroid Disorders

• Hypothyroidism- Hyposecretion
• Hyperthyroidism- Hypersecretion
• Graves Disease
• Goiters- iron deficiencies

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Parathyroids

• 4 small glands posterior surface of thyroid
• Parathyroid hormone
• Responsible for osteoclast of bone
• Decreases blood phosphate levels
• (By way of kidneys)
• Enhances activation of Vitamin D

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Parathyroid Disorders

• Hyperparathyroidism
• Moan and groan, stones and bones

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Pineal Gland

• Forms part of diencephalon
• Melatonin
• Inhibits hypothalamus release of gonadotropins
• Melatonin-decreases in light/increase in dark
  (circadian rhythm)

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Thymus Gland

• Posterior to sternum, around great vessels
• Thymosin
• Both lymphatic and endocrine
• Lymphatic- produces T-lymphocytes
• Endocrine- programs T-cells

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The Adrenals

• Located on superior end of each kidney
• Medulla- inner gland
• Cortex- outer gland

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Adrenal Medulla

• Sympathetic preganglionic fibers synapse on cells
  in medulla
• Release of epinephrine/norepinephrine into
  general circulation

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Adrenal Cortex

• Produce over 30 steroid hormones
• Three main cortical hormones
• Mineralocorticoids
• Glucocorticoids
• Sex hormones

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Mineralocorticoids

• Regulate levels of electrolytes and water in
  extracellular fluid
• 95 are aldosterone
• Sodium reabsorption
• Potassium excretion

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Glucocorticoids

• Influence carbohydrate metabolism
• Important in bodys response to stress
• 95 cortisol (hydrocortisone)
• stimulates gluconeogenesis
• secretion is regulated by ACTH

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Sex Hormones

• Androgens (testosterone)
• Estrogens
• Both are secreted in greater numbers by gonads

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Adrenal Disorders

• Cushings disease-
• cortisol over-production secondary to
• increased ACTH
• Addisons Disease-
• cortisol/aldosterone deficiencies

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Gonads

• Testes- males
• Testosterone
• Ovaries- females
• Estrogens
• Progesterone
• Both produce hormones/gametes

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Pancreas

• Retroperitoneal-posterior to stomach
• Exocrine Endocrine
• Endocrine- islets of Langerhans
• Alpha
• Beta
• Delta

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Alpha cells

• 20 of islets
• Hormone glucagon
• Stimulates breakdown of glycogen in liver-
  raises glucose levels in blood
• (glycogenolysis glyconeogenesis)

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Beta Cells

• 75 of islets
• Hormone- insulin
• Decreases glucose levels

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Glucose Metabolism

• Organic components of food
• Carbohydrates (instant-energy)
• Glucose
• Fats
• Fatty acids/glycerols
• Proteins
• Amino acids

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Carbohydrate Metabolism

• Insulin is released by humoral, hormonal, neural
  means
• Increased glucose
• Parasympathetic stimulation
• Gastrointestinal hormones

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Carbohydrate Metabolism

• 60 of carbohydrates are stored as
• glycogen in liver
• If muscles are not exercised after
  eating-stored as muscle glycogen

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Glycolysis

• Glucose is broken down into pyruvate
• and lactate- releasing 2ATPs
• (Anaerobic metabolism)
• Krebs Cycle

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Fat Metabolism

• A third of any glucose passing through liver is
  converted to fatty acids
• Fatty acids are converted to triglycerides and
  stored in adipose tissue

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Fat Metabolism

• Without insulin, fat is broken back down into
  triglycerides/cholesterol ? CAD
• Fatty acids are also broken down into ketone
  bodies

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Protein Metabolism

• In absence of insulin- protein storage stops and
  breakdown begins (muscle)
• Amino acid breakdown for energy leads to
  increased urea in urine? organ dysfunction

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Pancreas Disorders

• Diabetes-
• Type 1- Juvenile onset
• Type 2- Mature onset
• Gestational diabetes

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Type 1 Diabetes

• Insulin dependant
• S/S polyuria
• polydipsia
• polyphagia
• blurred vision
• weight loss

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Type 2 Diabetes

• Generally non-insulin dependant
• Has ability to make small amounts of
• insulin
• Can develop into insulin dependant

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Gestational Diabetes

• Develops during pregnancy
• Deficiencies in insulin leads to inability to
  metabolize carbohydrates
• Generally disappears after delivery

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Insulin Agents

• Early- porcine, bovine
• Recent- genetic engineered human insulin
• Protein
• Rapid, intermediate and long-term
• Combination of long-term, rapid each day

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Insulin Types

• Regular- Fast acting
• 0.5-1 hour onset
• 6-8 hour duration
• NPH- Intermediate
• 1-1.5 hour onset
• 24 hour duration

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Insulin Types

• Ultralente- Long acting
• 4-6 hour onset
• 36 hour duration
• Oral agents
• Diabinese (chlorpropamide)
• Orinase (tolbutamide)
• Micronase (glyburide)
• Glucotrol

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Diabetic Emergencies

• Hypoglycemia
• Hyperglycemia
• Diabetic Ketoacidosis (DKA)
• Hyperosmolar Hyperglycemic Nonketotic Coma (HHNK)

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Hypoglycemia

• Rapid on-set
• lt 60 mg/dl
• Causes too much insulin
• decreased intake salicylates
• excessive activity beta blockers
• emotional stress hypothermia
• chronic alcoholism sepsis

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S/S of Hypoglycemia

• Altered LOCs- irritability, nervousness,
• confusion, combative
• Cool, clammy
• Weak, rapid pulse
• Snoring, ? salivation
• Normal BP

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Diabetic Ketoacidosis

• Fat metabolism leads to ketoacids
• Acidosis leads to ? K in circulation
• hyperkaluria ? K deficiency
• Osmotic diuresis ? dehydration,
• electrolyte imbalances

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S/S of DKA

• Warm, dry skin
• Dry mucous membranes
• Tachycardia, thready pulse
• Postural hypotension
• Weight loss
• Polys

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S/S of DKA

• Abdominal pain
• Anorexia, nausea/vomiting
• Acetone breath
• Kussmauls
• Decreased LOC

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Hyperosmolar Hyperglycemic Nonketotic Coma

• Generally Type II diabetic
• Osmotic diuresis secondary to ? sugars
• Not acidotic as in DKA
• Factors Geriatric
• Preexisting diseases
• Increased insulin requirements
• Medication use- thiazide, diuretics
• Parenteral/enteral feedings

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S/S of HHNK

• Weakness
• Thirst
• Polyuria
• Weight Loss
• Extreme dehydration

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Treatment of Diabetic Emergencies

• Hypoglycemia- ABCs
• IV- NS
• Monitor ECG
• Oral, IV Dextrose
• Poss. Glucagon IM
• Poss. Thiamine
• Monitor glucose!

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Treatment of Diabetic Emergencies

• Hyperglycemia (DKA, HHNK)-
• ABCs
• O2
• IV- NS
• Monitor ECG for abnormalities