Endocrine System

• Endocrine glands secrete hormones into interstitial fluid. Then, the hormones diffuse into the blood.
• Ductless — no direct connection between each gland
• Exocrine glands — sweat glands, etc
• Hypothalamus

  • Portion of the diencephalon of the brain, forming the floor and part of the lateral wall of the third ventricle
  • Activates, controls, and integrates the peripheral autonomic nervous system, endocrine processes, and many somatic functions, such as body temperature, sleep, and appetite.
  • Controls pituitary gland
• Pituitary gland

  • The master gland, located at the base of the brain
  • It is influenced by the hypothalamus and promotes growth of body tissue, influences water absorption by the kidney, and controls sexual development and function.
• Anterior — adenohypophysis (grandular tissue)
• Posterior — neurohypophysis (neural tissue)
• • Sex — estrogen, testosterone 
  • Zona reticularis
• • Salt — mineralocorticoids, aldosterone
  • Zona glomerulasa
• • Sugar — glucocorticoids
  • Zona fasciculata
• Adrenal Gland

  
  

  Cortex

  • Outer shell of the adrenal gland (covering)
  • Synthesizes glucocorticoids and mineralocorticoids and secretes small amounts of sex hormones
• Medulla 

  • Inner core of the adrenal gland
  • Works as part of the sympathetic nervous system and produces catecholamines (epinephrine and norepinephrine)
• Thyroid gland

  • Functional unit — follicular cell
  • Located in the anterior part of the neck
  • Controls the rate of body metabolism and growth and produces thyroxine (T4), triodothyronine (T3), and thyrocalcitonin
• Parathyroid glands

  • Located on the thyroid gland
  • Controls calcium and phosphorus metabolism
  • Produces parathyroid hormone
• Pancreas

  • Functional unit — islet of langerhands (alpha, beta, and delta cells are here)
  • Located posteriorly to the stomach
  • Influences carbohydrate metabolism, indirectly influences fat and protein metabolism, and produces insulin and glucagon
• Alpha cells secrete glucagon (increases glucose)
• Beta cells secrete insulin (decreases glucose)
• Delta cell - secrete somatostatin (growth hormone, inhibitory hormone)

  • Decreases the release of growth hormone, TSH (thyroid stimulating hormone), and prolactin
  • Acts as a regulator of intestinal absorption of glucose
• Physiology

  Hypothalamus will stimulate pituitary gland

  • It releases releasing hormone
  • It includes the CRH (Corticotropin-releasing hormone), GnRH (Gonadotropin-releasing hormone), GHRH (Growth hormone-releasing hormone), TRH (Thyrotropin-releasing hormone), and somatostatin (inhibiting hormone)
• Ex. Hypothalamus secretes CRH, it will send that signal that releasing hormone to anterior pituitary gland to secrete ACTH (Adrenocorticotropic hormone) and MSH (Melanocyte-stimulating hormone) = directed to adrenal gland
• Cortex

  salt, increased sodium, increased water — decreased potassium

  sugar, metabolism — carbs, proteins, and lipids — decreased calcium absorption

  sex, — activates testosterone, estrogen, progesterone
• Medulla

  Epinephrine

  • Increased heart rate, increased contractility, increased cardiac output
  • Glycogenolysis

  Norepinephrine 

  • Same as epi
  • Vasoconstriction
• MSH, kapag nastimulate siya ng CRH, increased ang production ng melanin.
• Cushing disease — increased stimulation of ACTH, mas na stimulate si cortex and medulla na mag secrete ng hormones
• Corticosteroids = salt, sugar, and sex
• GnRH

  • FSH (Follicle-stimulating hormone)
  • LH (Luteinzing Hormone)
  • Both responsible for ovulation and production of estrogen and progesterone.
• GHRH

  • Stimulates growth hormone 
  • Growth hormone = bone and muscle growth, increased protein synthesis, increased fat metabolism, decreased carbs metabolism
• TRH 

  • Prolactin
  • Produces milk
• • Thyroid stimulating hormone
  • Stimulate thyroid gland and thyroid gland will release T3/T4 and calcitonin = bone formation
  • Mas mabilis effect ng t4
  • Activates Sympathetic nervous system
  • Increased metabolic rate and increased protein and bone resorption
  • Increased sebaceous glands and sweat glands
• Somatostatin — inhibition of GHRH
• Oxytocin — uterine contraction and milk ejection
• Antidiuretic hormone, vasopressin — conserves H20, vasoconstrictor
• PTH release when serum calcium is decreased, it will promote bone resorption