Chapter 10: Endocrine System

• Endocrine System


  Composed of endocrine glands and specialized endocrine cells located throughout the body
• Endocrine System Functions

  1. Regulation of metabolism

  2. Control of food intake and digestion

  3. Modulation of tissue development

  4. Regulation of ion levels

  5. Control of water balance

  6. Regulation of cardiovascular function

  7. Control of blood glucose and other nutrients

  8. Control of reproductive functions

  9. Stimulation of uterine contraction and milk release

  10. Modulation of immune system function
• Water soluble hormones


  Most common type of hormone; includes proteins, peptides, amino acids

  ex. growth hormone, antidiuretic, prolactin
• Lipid soluble hormone


  include steroids and eicosanoids

  ex. luteinizing hormone, androgens
• Pituitary gland


  Small gland in the brain; controlled by hypothalamus; secretes at least 6 hormones
• Growth hormone (anterior pituitary hormone)


  Target tissues: most tissues

  stimulates growth or bones, muscles and organs
• Giantism


  Caused by too much growth hormone
• Dwarfism


  Caused by too little growth hormone
• Thyroid-Stimulating Hormone (anterior pituitary hormone)


  Target issues: thyroid gland

  regulates thyroid gland secretions
• Thyroid gland enlarges (goiter)


  caused by too much TSH
• Thyroid gland shrinks


  Caused by too little TSH
• Gonadotropin Hormone Luteinizing Hormone for females (anterior pituitary hormone)


  Target tissues: ovaries

  promotes ovulation and progesterone production
• Gonadotropin Hormone Luteinizing Hormone for males (anterior pituitary hormone)


  Target tissues: testes

  production of sperm and testosterone
• Gonadotropin Hormone Follicle Stimulating Hormone for females (anterior pituitary hormone)


  Target tissues: follicles in ovaries

  follicle maturation and estrogen secretion
• Gonadotropin hormone Follicle stimulating hormone for males (anterior pituitary hormone)


  Target tissues: seminiferous tubules

  sperm production
• Prolactin (anterior pituitary hormone)


  Target tissues: mammary glands and ovarie

  milk production
• Melanocyte stimulating hormone (anterior pituitary hormone)


  Target tissues: melanocytes in the skin

  stimulates melanin production in melanocytes
• Adrenocorticotrophic hormone (anterior pituitary hormone)


  Target tissues: cells of adrenal cortex

  stimulates production of certain corticosteroids
• Antidiuretic hormone (posterior pituitary hormone)


  Target tissues: kidneys

  conserves water
• Diabetes insipidus


  Low ADH

  Kidneys to produce large amounts of dilute

  watery urine

  can lead to dehydration and thirst
• Oxytocin (Posterior Pituitary Hormone)


  Target tissues: uterus

  Increases uterine contractions during labor
• Thyroid Gland


  One of the largest gland; requires iodine to function

  Secretes thyroid hormone and calcitonin
• Thyroid hormones secreted by follicular cells


  Target tissues: most tissues

  Functions: regulates metabolic rates and is needed for growth
• Calcitonin secreted by parafollicular cells


  Target tissues: bone and some other tissues

  Function: reduces blood calcium level when high
• Hypothyroidism

  Decreased metabolism

  Myxedema in adults

  Cretinism in infants
• Hyperthyroidism

  Increased metabolism

  Graves’ disease leads to goiter
• Parathyroid Hormone (PTH)


  Target tissues: bones and kidneys

  Functions: regulates blood Ca2+ levels (more than calcitonin)
• If Ca2+ is low, then osteoclasts break down bone matrix and less Ca2+ is lost in urine.
• If Ca2+ is high, then osteoclasts don’t break down bone matrix and more Ca2+ is lost in urine.
• The adrenal glands are two small glands located superior to each kidney
• Adrenal medulla


  Inner part of adrenal gland
• Adrenal Cortex


  Outer part of adrenal gland
• Epinephrine/Norepinephrine (Adrenal Medulla Hormones)

  Target tissues: heart, blood vessels, liver, fat cells

  Functions: released as part of fight or flight response
• Aldosterone (Adrenal Cortex Hormones)

  Type of mineralocorticoid

  Target tissues: kidneys

  Functions: regulate ion balance, causes Na+ and H2O

  to be retained and K+ to be secreted, indirectly

  involved with blood pressure and blood volume
• Cortisol (Adrenal Cortex Hormones)

  Type of glucocorticoid

  Target tissues: most

  Functions: increases breakdown of fat and protein for

  energy uses reduces inflammatory and immune

  responses
• Androgens (Adrenal Cortex Hormones)

  Target tissues: most tissues

  Functions:

  Males: secondary sexual characteristics

  Females: sex drive
• Pancreas

  is a mixed gland, with an exocrine portion and an endocrine portion
• Exocrine Portion of Pancreas

  Secretes digestive enzymes
• Endocrine Portion of Pancreas


  consists of pancreatic islets (Islets of Langerhans), which are

  dispersed throughout the exocrine portion of the

  pancreas.
• Alpha Cells (Islets)


  secretes glucagon