BIO 2

• Endocrine system


  Our body's messenger system
• Hormones


  Chemical substances released by glands into the blood that affect a lot of bodily functions
• Hormones do much more than influence our mood. Without hormones our bodies simply would not function.
• Functions of the endocrine system

  • Mood control
  • Individual growth
  • Metabolism
• Parts of the endocrine system

  • Pituitary
  • Adrenals
  • Pancreas
  • Thyroid
  • Parathyroid
  • Gonads
• Pituitary gland


  The master gland, primary function is to control other glands
• Hormones produced by the anterior/ventral pituitary

  • Thyroid-stimulating hormone (TSH)
  • Growth hormone (GH)
  • Adrenocorticotropin (ACTH)
  • Follicle-stimulating hormone (FSH)
  • Luteinizing hormone (LH)
  • Prolactin
• Oxytocin

  Stimulates the gravid uterus and causes "let down" of milk from the breast
• ADH (vasopressin)

  Causes the kidney to retain water
• Thyroid gland


  Releases thyroid hormones that control metabolism
• Calcitonin

  Hormone produced by the thyroid that lowers the amount of calcium in the blood
• Hypothyroidism (Myxedema)


  Inadequate levels of thyroid hormones, causes facial bloating, weakness, cold intolerance, lethargy, altered mental status, oily skin and hair
• Hyperthyroidism (Graves' disease)

  Increased thyroid hormone release, causes insomnia, fatigue, tachycardia, hypertension, heat intolerance, weight loss
• Parathyroid gland

  Regulates the level of calcium in the body
• Pancreas


  Key gland located in the folds of the duodenum, has both endocrine and exocrine functions
• Islets of Langerhans

  Specialized tissues in the pancreas where the endocrine functions occur, include alpha, beta, and delta cells
• Adrenal glands

  Small glands that sit atop the kidneys, secrete hormones like adrenaline and noradrenaline
• Gonads

  The endocrine glands associated with human reproduction, female ovaries and male testes
• Estrogen and progesterone

  Hormones produced by the ovaries that have functions including sexual development and preparation of the uterus for implantation
• Testosterone


  Hormone produced by the testes that promotes male growth and masculinization
• Endocrine system produces hormones that are released directly into the bloodstream
• Pituitary gland


  A small gland located on a stalk hanging from the base of the brain, secretion is controlled by the hypothalamus
• Pathogens are disease causing microorganisms, molecules, and viruses
• Virus


  A small pathogen that can only replicate itself inside the living cells of other organisms, has a protein capsid that holds its genetic material

  
• Bacteria


  Unicellular organisms that have a plasma membrane, cytoplasm, ribosomes, and DNA, most also have a cell wall
• Types of bacteria


  • Spherical (cocci)
  • Rod (bacilli)
  • Spiral (spirilla)
  • Comma (vibrios)
  • Corkscrew (spirochaetes)
• Lymphatic system


  Attacks pathogens that threaten the body and plays a supporting role in circulation by recycling fluid that leaks from the circulatory system
• Lymphoid organs


  • Tonsils & adenoids
  • Lymph nodes
  • Appendix
  • Bone marrow
  • Thymus
  • Spleen
  • Peyer's patch

  
• Bone marrow


  Spongy tissue inside some bones where blood stem cells produce lymphoid and myeloid progenitor cells that give rise to immune cells
• Thymus


  Where T cells develop from lymphoid progenitor cells, T cells produce T cell receptors that bind to antigens
• Spleen


  Main function is to remove old or damaged cells from the blood, contains phagocytes and lymphocytes
• Lymph nodes


  Found throughout the body, connected by lymphatic vessels that absorb fluid leaking from blood vessels, pathogens can enter lymphatic vessels and travel to lymph nodes

  
• Phagocytes


  Dendritic cells and macrophages that engulf and destroy abnormal, infected, or old red blood cells and recycle their components

  
• Spleen


  • Contains B cells and T cells that help fight pathogens

  
• Reasons for spleen removal


  1. Damage

  2. Enlargement

  3. Cancer
• Lymph nodes


  Found throughout the body and connected by lymphatic vessels that absorb fluid leaking out of blood vessels into tissues

  
• Pathogens entering lymphatic vessels


  1. Travel to lymph nodes

  2. Targeted by immune cells including B cells, T cells, and phagocytes
• Barriers to infection


  • Skin
  • Mucous membranes
  • Digestive system
  • Respiratory system

  
• Mechanism of immune system


  Defends against day-to-day invaders
• Purpose of lymphatic system

  Carries nutrients, delivers nutrients to all parts of the body, gathers invaders and takes them to lymph nodes filled with white blood cells