Endocrine System

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Endocrine System

• Health Science One

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Function of endocrine system

• Endocrine glands - Secrete chemicals, hormones,
  directly into bloodstream.
• - Ductless glands
• Exocrine glands - Secrete substance through a
  duct i.e.Sweat, salivary, lacrimal and
  pancreas.
• Hormones chemical substances that coordinate
  and direct target organ cells (only specific
  cells respond)

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Negative Feedback

• Drop in hormone level triggers chain reaction
• Blood level of hormone falls
• Brain gets message and sends out hormone to
  stimulate gland
• Gland secretes more hormone
• When blood levels of hormone increase, the brain
  hormones stop

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Nervous Control

• In some cases, sympathetic nervous system causes
  direct release of hormone from gland
• i.e. stress may cause the adrenal medulla to
  secrete adrenaline

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Pituitary Gland

• Tiny size of a grape
• Base of brain
• Connected to hypothalamus
• Anterior / Posterior lobes
• Cranial cavity
• Master Gland

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Anterior Pituitary Lobe

• GH Growth hormone (somatotropin) responsible
  for growth and development
• Prolactin develops breast tissue, stimulates
  production of milk after childbirth
• TSH Thyroid stimulating hormone stimulates
  thyroid cells to produce thyroid hormone
  thyroxine (low TSH treated with synthroid)
• ACTH Adrenocortiocotropic hormone stimulates
  adrenal cortex

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Anterior Pituitary contd

• FSH Follicle stimulating hormone stimulates
  growth of follicle and production of estrogen in
  females and sperm in males
• LH Luteinizing hormone stimulates ovulation
  and formation of corpus luteum, which produces
  progesterone in females

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Posterior Pituitary Lobe

• Vasopressin converts to ADH (antidiuretic
  hormone) in the bloodstream, acts on kidney to
  concentrate urine and preserve water in the body
• Oxytocin released during childbirth causing
  contractions of the uterus

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Thyroid Gland

• Thyroid Gland
• 1. Butterfly-shaped mass of tissue.
• 2. On either side of larynx, in front of the
  trachea.
• 3. H-shaped.

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• Thyroid stimulating hormone (stimulates
  cellular metabolism) Main hormone Thyroxine
  controlled by secretion of TSH controls rate of
  metabolism
• Calcitonin controls calcium ion concentration
  in the body prevents hypercalcemia

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Parathyroid Glands

• 4 glands size of a grain of rice
• Attached to posterior thyroid
• Produce parathormone which helps control blood
  calcium, prevents hypocalcemia.

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Thymus Gland

• Endocrine and lymphatic organ
• Behind (posterior) sternum, above and in front of
  heart
• Begins to disappear at puberty
• Produces Thymosin reacts upon lymphoid tissue
  to produce T-lymphocytes

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Adrenal Glands

• Adrenal Glands above kidneys
• Adrenal cortex secretes corticoids
  (anti-inflammatory hormones) and sex hormones
• Androgens Male sex hormones
• Adrenalin hormone from adrenal medulla,
  powerful cardiac stimulant, fight or flight
  hormone response to stress

Adrenal Medulla also secretes nor epinephrine
increases BP and heart rate and constricts blood
vessels.
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Gonads

• Gonads ovaries in female and testes in male
• Estrogen Development of female reproductive
  organs, secondary sex characteristics (breasts,
  pubic hair, menstrual cycle)
• Progesterone Plays a part in the menstrual
  cycle
• Testosterone Male reproductive organs and
  secondary sex characteristics (chest hair, deep
  voice, increased muscle mass)

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Pancreas

• Pancreas abdominal cavity behind the stomach
• Endocrine and exocrine functions also part of
  digestive system
• Islets of Langerhans Insulin production.
• Insulin promotes utilization of glucose by the
  cells lowers blood sugar levels

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Other hormones

• Prostaglandins Tissue hormones - can cause
  constriction of blood vessels and muscle
  contractions - can be used to induce labor.

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Endocrine Disorders - Dwarfism

• Hypofunction of pituitary in childhood
• Small size, but body proportions and intellect
  normal
• Sexual immaturity
• Rx Early diagnosis, injection of growth hormone

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Gigantism

• Gigantism
• Hyperfunction of pituitary Too much growth
  hormone
• In preadolescence Overgrowth of long bones
  leads to excessive tallness

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Acromegaly

• Hyperfunction of pituitary too much growth
  hormone in adulthood
• Overdevelopment of bones in face, hands and feet
• Attacks cartilage so the chin protrudes -
  lips, nose and extremities enlarge
• Rx drugs to inhibit growth hormone radiation

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Before

• After

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Hyperthyroidism

• Overactive thyroid gland
• Too much thyroxin leads to enlargement of gland
• Symptoms Consuming large quantities of food but
  lose weight nervous irritability
• Goiter Enlargement of gland
• Exophthalmos Bulging of eyeballs
• TX Partial or total removal of gland, drugs to
  reduce include thyroxine radiation

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Hypothyroidism

• Not enough thyroxine
• May be due to lack of iodine (simple goiter)
  fixed with iodized salt
• Other cause inflammation of thyroid which
  destroys the ability of the gland to make
  thyroxine
• Sx Dry, itchy skin dry and brittle hair,
  constipation, muscle cramps at night.

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Tetany

• In hypoparathyroidism, decreased calcium levels
  affect functions of nerves
• Sx Convulsive twitching develops, person dies of
  spasms in the respiratory muscles, seizures
• Rx Vitamin D, calcium and parathormone.

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Addisons Disease

• Adrenal glands dont produce enough cortisol or
  aldosterone (steroid hormones)
• Sx muscle weakness, darkening of skin
  (hyperpigmentation), salt craving, irritability,
  hair loss, depression, weight loss, n/v/d,
  hypoglycemia, low BP

Steroid abuse liver damage, heart disease,
testicular changes, breast growth in males
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Diabetes Mellitus

• Cause Decreased secretion of insulin
• Sx-Polyuria, polyphagia, polydipsia, weight loss,
  blurred vision, and possible diabetic muscles.
• If not treated, excess glucose in blood
  (hyperglycemia) and secreted in urine
  (glycosuria)
• If too much insulin given, blood sugar can get
  too low (hypoglycemia) and person can develop
  insulin shock.
• Type II diabetes is not insulin-dependent Most
  common, usually familial, occurs later in life,
  usually treated with diet.
• Test for diabetes Blood sample at home, normal
  blood sugar is 80-100 mg. screeningurinalysis

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Hyperglycemia (High Blood Glucose)

• Causes Too much food, too little insulin or
  diabetes medicine, illness or stress.
• Onset Gradual, may progress to diabetic coma.
• Symptoms Extreme thirst, frequent urination,
  dry skin, hunger, blurred vision, drowsiness, and
  nausea.
• What can you do? Take blood glucose tests, and
  if over 250 mg/dL for several tests, call your
  doctor.

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Hypoglycemia(Low Blood Glucose)

• Causes Too little good, too much insulin or
  diabetes medicine, or extra exercise.
• Onset Suddon, may progress to insulin shock.
• Symptoms Shaking, fast heartbeat, sweating,
  anxious, dizziness, hunger, impaired vision,
  weakness fatigue, headache, and irritablility.
• What can you do? Drink ½ glass of orange juice
  or skim milk, or eat several hard candies, test
  your blood glucose if symptoms dont stop call
  your doctor, within 30 minutes after symptoms go
  away, eat a light snack (a ½ peanut butter or
  meat sandwich and a ½ glass of mik.

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Endocrine Terminology

• 1. Thyroxine Regulates body metabolism
• 2. Adrenalin Stimulates the heart to beat
  faster
• 3. Parathyroid Regulates use of calcium
• 4. Parathormone Control use of calcium
  phosphorus
• 5. Insulin Secreted by pancreas
• 6. Calcitonin Affects neuromuscular functioing,
  blood clotting, and holds cells together
• 7. Estrogen Governs reproduction and fertility
• 8. Oxytocin Causes the uterus to contract
  during labor
• 9. Gonad Sex gland
• 10. ACTH Hormone secreted by the pituitary gland

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Endocrine Terminology Cont.

• 11. Acromegaly Enlargement of bones of the
  extremities.
• 12. Adenectomy Removal of any gland.
• 13. Adenoidectomy Removal of the adenoids.
• 14. Adrenogenic Originating in the adrenals.
• 15. Dwarfism Condition of being abnormally
  small.
• 16. Endocrine Ductless to secrete within.
• 17. Endocrinotherapy Treatment with endocrine
  preparation.
• 18. Exocrine To secrete through a duct.
• 19.Goiter Enlarged thyroid gland.

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Endocrine Terminology Cont.

• 20. Goitrogens Any substance that causes a
  goiter.
• 21. Lymphycytopenia Deficiency of lymph cells.
• 22. Pancreatolysis Breakdown of the pancreas.
• 23. Parathyrotoxicosis Poisonous condition of
  the parathyroid.
• 24. Pinealoma Tumor of the pineal gland.
• 25. Pituitarigenic Originating in the
  pituitary.
• 26. Thyroadenitis Inflammation of the thyroid
  gland.