The Endocrine System

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The Endocrine System

• Chapter 18

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General Characteristics

• includes cells, tissues, and organs that secrete
  hormones directly into the body fluids to help
  regulate metabolic processes such as chemical
  reactions, reproduction, growth, and development
• The 9 Endocrine glands include the 1. pituitary
  (anterior and posterior), 2. thyroid, 3.
  parathyroid, 4. adrenal, 5. pineal, 6. thymus, 7.
  pancreas, 8. testes, and 9. ovaries

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Hormones

• biochemicals secreted by a cell that affect the
  function of another cell
• 3 types
• Steroid derived from cholesterol (fat)
• Peptide an amino acid based hormone (protein)
• Prostaglandins hormone-like lipids (fat) act
  more locally than hormones only affect organ
  where produced
• Hormones are released based on the bodys need
  and are carried by the blood to the target cell
  controlled by negative feedback

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Hormones of Anterior Pituitary
Hormone Target tissue Effects
Adreno - corticotropic hormone (ACTH) Adrenal glands Stimulates production of steroid hormones
Follicle- stimulating hormone (FSH) Ovaries and testes Regulates development of male/female gametes and production of testosterone in testes of males
Luteinizing hormone (LH) Ovaries and testes Stimulates release of egg from ovary stimulates production of testosterone
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Hormones of Anterior Pituitary (cont).
Hormone Target tissue Effects
Prolactin Mammary glands Stimulates milk production in breasts
Growth hormone or somatotropin (GH) All tissues stimulates cell growth and division, particularly bone and muscle
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Hormones of Posterior Pituitary
Hormone Target tissue Effects
Antidiuretic hormone (ADH) Kidneys, blood vessels Stimulates absorption of water (less urine production) and thereby regulates water balance
Oxytocin Mammary glands, uterus Stimulates uterine contractions, onset of labor, and the letting down of milk to the breasts.
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Hormones of Adrenal Glands
Hormone Target tissue Effects
Aldosterone Kidneys Maintains blood volume and pressure (stimulates kidneys to conserve sodium, and therefore retain water)
Cortisol All tissues Controls inflammation, increases blood glucose concentration, suppresses immune response
Epinephrine and norepinephrine Skeletal and cardiac muscle, blood vessels Initiates response to stress increases metabolic rate, heart rate, blood pressure dilates blood vessels raises blood glucose levels
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Hormones of Pancreas
Hormone Target tissue Effects
Insulin All tissues Stimulates conversion of glucose to glycogen lowers blood glucose levels
Glucagon Liver, fatty tissues Stimulates conversion of glycogen to glucose raises blood glucose levels
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Hormones of Pineal Gland
Hormone Target tissue Effects
Melatonin Uncertain, possibly testes and ovaries May regulate biorhythms and moods may control onset of puberty
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Hormones of Thyroid Gland
Hormone Target tissue Effects
Calcitonin Bone tissue Inhibits release of calcium from bone lowers blood calcium levels (opposite of parathyroid hormone)
Thyroxine All tissues Raises metabolic rate necessary for normal growth
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Hormones of Ovaries
Hormone Target tissue Effects
Estrogen All tissues, female reproductive structures Controls dev. of secondary sex charac. and sex organs initiates preparation of uterus for pregnancy
Progesterone Uterus, breasts Completes preparation of uterus for pregnancy stimulates breast dev.
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Hormones of Testes
Hormone Target tissue Effects
Testosterone All tissues, male reproductive organs Controls dev. of secondary sex charac. and sex organs stimulates sperm formation
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Hormones of Parathyroid Gland
Hormone Target tissue Effects
Parathyroid hormone (PTH) Bone tissue, kidneys Stimulates breakdown of bone and release of calcium into bloodstream raises blood calcium levels
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Hormones of Thymus Gland
Hormone Target tissue Effects
Thymosin Bone Marrow Altered in spleen Regulates production of white blood cells (immunity)
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Disorders - Pituitary Gland

• Diabetes insipidus deficiency of ADH
  characterized by large volumes of dilute urine
  and constant thirst usually caused by an injury
  to the head, complications with brain surgery, or
  a brain tumor can be genetic

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Disorders - Pituitary Gland (dwarfism)

• Pituitary Dwarfism any person who is under 4
  10 tall is considered a dwarf. Is caused by a
  deficiency of HGH in adolescence limbs
  proportional and normal mental development but
  may not develop adult sex features. 10,000 to
  15,000 in U.S.
• Achondroplasia - is the most common type of
  dwarfism. It is characterized by abnormal body
  proportions. Affected individuals have arms and
  legs that are very short, while the torso is
  nearly normal size. Caused by mutation on
  chromosome 3 effects cartilage formation. 80 of
  dwarves

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Achondroplasia
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Disorders - Pituitary Gland (gigantism)

• Gigantism overproduction of HGH in adolescence
  height may exceed 8 ft rare, usually result of
  tumor (or small tumors) other hormones of
  pituitary gland usually affected so other
  hormone-related problems. Top 1 in height.
• Acromegaly overproduction of HGH after puberty
  and growth plates have fused can cause type 2
  diabetes, high blood pressure, increased risk of
  cardiovascular disease, and arthritis.

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12 yr old boy with mother
8 ft 11 inches
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Disorders - Pancreas

• Diabetes mellitus insulin deficiency inhibits
  conversion of glucose to glycogen? therefore
  blood sugar is too high results in excess urine
  output also, cells use protein for energy
  instead of sugar so body tissues waste away
  results are weight loss, hunger, fatigue,
  dehydration
• Type I juvenile autoimmune disease immune
  system attacks cells that synthesize insulin
  treatment insulin injections
• Type II adult usually appears after age 40
  usually in overweight adults body cells lose
  sensitivity to insulin treatment controlling
  diet, exercise, maintaining healthy body weight

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Diabetes

• Hypoglycemia low blood sugar (can cause
  diabetic coma). No energy
• Hyperglycemia high blood sugar (can cause the
  rupture of blood vessels, blurred vision, thirst,
  hunger, and frequent urination.
• Gestational Diabetes Diabetes during pregnancy
  caused by high level of production of FSH and LH
  which blocks the effectiveness. Typically not a
  problem after pregnancy and does not usually
  cause birth defects like normal diabetes if
  managed correctly.

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Disorders - Thyroid

• Graves disease (hyperthyroidism) elevated
  metabolic rate restlessness overeating eyes
  protrude b/c of swelling in the tissues behind
  them thyroid gland enlarges? causes swelling in
  neck called a goiter
• Hypothyroidism in infants called Cretinism
  stunted growth, abnormal bone formation mental
  retardation low body temp sluggishness in
  adults called Myxedema lethargy hair loss low
  metabolic rate obesity more common in females

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Goiter
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Disorders Adrenal gland

• Cushings syndrome hypersecretion of cortisol
  alters carb and protein metabolism and
  electrolyte balances upper body obesity rounded
  face increased fat around neck thinning arms
  and legs
• Addisons disease hyposecretion of cortisol and
  aldosterone weight loss dehydration muscle
  weakness fatigue low blood pressure darkening
  of skin JFK had this disease

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Cushings syndrome
Same patient 2 yrs later after treatment
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Disorders Parathyroid

• Kidney stones too much PTH stimulates
  osteoclast activity bones soften, deform excess
  calcium in body fluids results in abnormal
  storage of calcium?kidney stones