Endocrine System

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Endocrine System
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Endocrine System

• Regulates overall metabolism, homeostasis, growth
  and reproduction
• Glands are organs that specialize in the
  secretion of substances needed by an organism
• Hormones are the secretions produced by the
  endocrine glands
• - released into the bloodstream

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Endocrine Glands

• Hypothalamus part of the CNS, but it produces
  hormones that influence the pituitary gland
• Pituitary Gland the master gland
• Located at the base of the brain
• Secretes growth hormone which affects growth of
  bone and cartilage

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Endocrine Glands (continued)

• Thyroid Gland
• Located in the neck
• Secretes thyroxine which regulates the rate of
  metabolism in the body
• Parathyroid Gland
• Embedded in the back of the thyroid
• Secretes parathormone which controls metabolism
  of calcium and phosphate

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Endocrine Glands (continued)

• Adrenal Glands
• Located on top of the kidneys
• Secrete adrenaline which helps deal with stress
  and accelerates the heart and breathing rates
• Islets of Langerhans specialized cells
• Located in the pancreas
• Secrete insulin and glucagon
• Insulin lowers blood sugar
• Glucagon raises blood sugar

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Endocrine Glands (continued)

• Gonads sex glands
• Male gonads are called testes
• Located in the scrotum
• Secrete testosterone which regulates male
  secondary sex characteristics
• Female gonads are called ovaries
• Located in the pelvic region
• Secrete estrogen and progesterone which regulate
  female secondary sex characteristics

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Feedback Mechanisms

• Negative Feedback is when an activity alters a
  condition in the body, and this triggers a series
  of events that reverses the altered condition
• Ex. Blood sugar levels
• When blood sugar goes up, insulin lowers blood
  sugar
• When blood sugar goes down, glucagon raises blood
  sugar
• Ex. Body temperature
• When body temp. goes up, we sweat
• When body temp. goes down, we shiver

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Negative Feedback Mechanisms

• Ex. Body temperature
• When body temp. goes up, we sweat
• When body temp. goes down, we shiver

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Positive Feedback Mechanisms (continued)

• Positive Feedback is when a change initiates a
  response, and that response intensifies the
  original change
• Ex. Contractions of the uterus during childbirth

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Endocrine Disorders

• Diabetes is a disease where a person cannot
  produce insulin
• Inability of the body to store sugar as glycogen
• Goiter is enlargement of the thyroid gland
  caused by iodine deficiency

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Endocrine Disorders

• Hyperthyroidism (overactive thyroid) a
  condition in which your thyroid gland produces
  too much of the hormone thyroxine.
  Hyperthyroidism can accelerate your body's
  metabolism significantly, causing sudden weight
  loss, a rapid or irregular heartbeat, sweating,
  and nervousness or irritability.

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Endocrine Disorders

• Acromegaly Acromegaly is a hormonal disorder
  that develops when your pituitary gland produces
  too much growth hormone during adulthood. When
  this happens, your bones increase in size,
  including those of your hands, feet and face.
  Acromegaly usually affects middle-aged adults.