ENDOCRINE SYSTEM

• A gland may be a separate structure, or it may be made up of groups of cells within an organ that function together to produce hormones.
• Although a hormone travels everywhere, it has an effect only on its target tissue because the cells of the target tissue have receptors for that specific hormone.
• Pineal Gland it resembles a pine cone.
• Pineal Gland is located beneath the posterior end of the corpus callosum in the brain.
• Pineal Gland , function in

  establishing sleep-wake cycles of daily biological rhythms. The hormone melatonin produced by the pineal gland is believed to suppress gonadotropin-releasing hormone

  (GnRH) from the hypothalamus.
• Melatonin Helps regulate daily biological rhythms;

  inhibits GnRH production
• ACTH

  (adrenocorticotropic

  hormone) Stimulates secretion of glucocorticoids

  and growth of the adrenal cortex
• GH (growth

  hormone)

  Stimulates widespread tissue growth
• ADH (antidiuretic

  hormone)

  KidneyS

  Increases water retention
• Oxytocin

  Uterus

  2. Lactating breasts

  1. Stimulates uterine contractions

  2. Stimulates release of milk
• T3 and T4 (thyroid

  hormone)

  Most tissues

  Elevates metabolic rate; increases heart and

  respiration rates; stimulates appetite
• Calcitonin

  Osteoblasts

  Stimulates bone deposition
• PTH (parathyroid

  hormone)

  Osteoclasts

  1. Stimulates bone reabsorption to increase

  blood calcium levels
• PTH (parathyroid

  hormone)

  2. Kidneys

  2. Stimulates reabsorption of calcium by the

  kidneys to maintain blood calcium levels
• PTH (parathyroid

  hormone)

  3. Small intestine

  3. Stimulates calcium absorption
• Pancreas Insulin

  Most tissues, liver

  Stimulates cells to take in glucose to lower

  blood glucose levels; tells liver to store

  glucose as glycogen
• pancreas Glucagon

  Liver

  Stimulates glycogen conversion to glucose and then its secretion to raise blood glucose levels
• Adrenal

  cortex

  Mineralocorticoids

  (aldosterone)

  Kidneys

  Promote sodium (Na+) and water reabsorption
• Adrenal cortex Mineralocorticoids(aldosterone) promote potassium (K+) excretion; maintain blood volume and pressure
• Glucocorticoids

  (cortisol)

  Most tissues

  Stimulate the breakdown of protein and

  fat to make glucose;
• Glucocorticoids(cortisol)Most tissues suppress the immune system; reduce inflammation
• Androgens

  (dehydroepiandrosterone

  [DHEA])

  Precursors to testosterone, responsible for

  male secondary sex characteristics and for

  sex drive in both sexes
• Adrenal medulla

  Epinephrine Most tissues Raises metabolic rate;
• Adrenal medulla Epinephrine Most tissues increases heart and respiration rates; increases blood glucose levels (complements sympathetic nervous system)
• Ovaries Estrogen Most tissues Stimulates female secondary sex characteristics;*

  regulates menstrual cycle and pregnancy
• Testes Testosterone Most tissues Stimulates male secondary sex characteristics,

  sex drive, and sperm production
• Prostaglandins Many tissues Have a variety of functions, such as relaxing

  smooth muscle in respiratory airways and

  blood vessels and causing contraction of

  smooth muscle in the uterus
• The hypothalamus is connected to the pituitary gland’s two parts by a stalk called

  the infundibulum, which serves as a passageway
• Nerve signals from the hypothalamus

  travel through the infundibulum and trigger the release of ADH and oxytocin from the

  posterior pituitary when they are needed.
• Thyroid hormone is vital to metabolism regulation in the body. The production of

  this hormone requires the mineral iodine.
• The pancreas is an elongated gland and has a

  pebbly appearance. It is inferior and posterior to the stomach. Only about 2% of the

  gland produces hormones for the endocrine system. The endocrine cells are grouped

  to form 1 to 2 million pancreatic islets (islets of Langerhans).
• The adrenal glands appear to sit as a cap, superior and medial to

  the kidneys.
• The adrenal cortex is the outer layer of the adrenal gland. It produces

  over 25 different hormones classified in three major categories: mineralocorticoids,

  glucocorticoids, and androgens.
• The adrenal medulla is the middle of the adrenal gland. It is often

  stimulated by the sympathetic nervous system in situations of fear, pain, and stress.
• The ovaries begin to produce their hormones at puberty and continue producing

  them until menopause. A major hormone produced in the ovaries is estrogen, which

  is responsible for the development of secondary sex characteristics in the female.
• Testes The testes produce the hormone testosterone in the fetus for the development

  of male anatomy. Testosterone production is dormant from birth to puberty,

  and then it begins again at puberty to promote the development of male secondary

  sex characteristics.
• the heart produces atrial natriuretic hormone (ANH), a hormone

  that targets the kidney to regulate urine production
• Steroid hormones are derived from a cholesterol molecule
• steroids As lipids,

  they can pass through cell membranes to reach receptors anywhere in the cell.
• Amino Acid Derivatives As the name implies, these hormones are derived from

  amino acids.