Endocrine System

• Endocrine System

  • consists of tissues (mainly glands) that create & release hormones
  • main function: release hormones into your blood while continuously monitoring the levels
• Hormones


  chemicals that coordinate diff. functions in body by carrying messages through blood to organs, skin, muscles, & other tissues
• Endocrine System Organs

  • Hypothalamus
  • Pancreas
  • Adipose Tissue
  • Gonads: Ovaries
  • Gonads: Testes
• Hypothalamus

  • located in the undersurface of the brain
  • link between the endocrine and nervous systems
  • controls major homeostasis processes
  • controls both endocrine & non-endocrine system
• Pancreas

  • behind stomach
  • releases 2 hormones essential to maintaining health blood sugar levels:
  • insulin - lowers blood glucose level
  • glucagon - increases blood glucose level
• Adipose Tissue

  • connective tissue that extends throughout body
  • found under skin, subcutaneous fat
  • between internal organs, visceral fat
  • in inner cavities of bones, bone marrow adipose tissue
  • releases many different hormones:
  • leptin, angiotensin, adiponectin
• Gonads: Ovaries

  • pelvic region within abdomen
  • produces 2 major steroid hormones: estrogen & progesterone
• Gonads: Testes

  • within scrotum in lower abdomen
  • produces testosterone
  • controls the development of secondary sex characteristics, muscle mass, bone density, & spermatogenesis
• Thymus

  • behind sternum between lungs
  • responsible for development & maturation of T cells
  • produces:
  • thymopoietin - T cell development & differentiation, maintenance of aging process of various cells
  • thymulin - promotes differentiation & normal funcs. of T cells, regulates releases of other hormones in body
  • thymosin - plays role in stimulating T cell production
• Endocrine Glands

  • Pineal Glands
  • Pituitary Glands
  • Thyroid Glands
  • Parathyroid Glands
  • Adrenal Glands
• Pineal Gland

  • deep in central portion of the brain, at the back of corpus callosum
  • secretes melatonin which induces sleep to control sleep-wake pattern/circadian rhythm
• Pituitary Gland

  • located at the base of the brain below hypothalamus
  • "master gland" that controls other endocrine glands' functions & activities
  • some secretions controlled by hypothalamus
• Thyroid Gland

  • near the base of neck
  • secretes thyroid hormones
  • controls metabolic rate, nervous development, rate of protein synthesis
  • prod. calcitonin, reduces blood calcium lvls
  • regulates blood phosphate & potassium lvls
  • prod. hormones: thriiodothyronine (T3), thyroxine (T4), calcitonin
• Parathyroid Gland

  • behind thyroid glands
  • secretes parathyroid hormones (PTH) = inc. blood calcium lvls
  • works alongside calcitonin to regulate blood calcium
  • calcitonin decreases calcium lvls; PTH acts to inc. them
• Adrenal Glands

  • above each kidneys
  • synthesize & secrete 3 major hormones: adrenaline, cortisol, aldosterone
• Adrenaline

  • promotes "fight-or-flight" responses; inc. heart rate, pupil dilation, redirecting of blood to muscles, inc. respiratory rate, & enlarging pupils
  • plays a role in max. energy utilization by the body & brain
• Cortisol

  • "stress hormone"
  • controls stress responses & maintains immune & metabolic functions
• Aldosterone

  • regulates salt & water balance & maintains normal blood pressure
• Other tissues that release hormones:

  • digestive tract
  • liver
  • kidneys
  • heart
  • placenta
• Digestive tract

  • stomach & small intestine
  • largest endocrine-related organ system
  • makes & releases several hormones that play role in metabolism
  • gastrin & ghrelin
• Kidneys

  • 2 bean-shaped organs that filter blood
  • part of urinary system, also prods. hormones:
  • erythropoietin & renin
• Liver

  • part of digestive system, also prods. hormones:
  • insulin-like growth factor 1 (IGF-1)
  • angiotensinogen
• Heart

  • when BP inc., releases 2 hormones:
  • A-type natriuretic peptide
  • B-type natriuretic peptide
• Placenta

  • temporary endocrine organ that forms during pregnancy
  • prods. hormones important for maintaining healthy pregnancy & preparing body for labor & breastfeeding