finals- endocrine

• Autocrine chemical messengers


  Stimulate the cells that originally secreted them ("auto" means self)
• Paracrine chemical messengers


  Act on nearby cells ("para" means katabi)
• Neurotransmitters


  Secreted in a synaptic cleft
• Endocrine chemical messengers


  Secreted into the blood stream
• Paracrine — A cell targets a nearby cell. (Signaling cell → Target cell)
• Autocrine — A cell targets itself.
• Secretion if hormones stimulate the cell itself
• NEUROTRANSMITTERS — transmitted into the synaptic cleft
• ENDOCRINE — A cell targets a distant cell through the bloodstream. (Signaling cell → bloodstream → Target cell)
• Blood will be circulated all throughout the body kaya yung mga signaling cell l, pag nag secrete sila ng hormone nakakarating pa rin sila sa target cell because of the bloodstream.
• Functions of the endocrine system


  • Metabolism
  • Control of food intake and digestion
  • Tissue development
  • Ion regulation
  • Water balance
  • Heart rate and blood pressure regulation
  • Control of blood glucose and other nutrients
  • Control of reproductive functions
  • Uterine contractions and milk release
  • Immune system regulation
• Major endocrine glands


  • Pineal gland
  • Pituitary gland
  • Thyroid gland
  • Parathyroid glands
  • Thymus
  • Adrenal glands
  • Pancreas
  • Ovaries(females)
  • Testes(males)
• Cell membrane is composed of phospholipid bilayer and is selectively permeable (not every ions and molecules can pass through the inside of the cell)
• In phospholipid bilayer, some hormones can pass through it but some hormones cannot pass through it.
• Mayroon lang iba na nakakadaan dito by the intracellular fluid.
• Water soluble hormones


  Cannot pass through the cell membrane
• Lipid soluble hormone


  Lipids can pass through the cell membrane
• Lipid-soluble hormones


  • Non-polar
  • Include steroid hormones, thyroid hormones, and eicosanoids
  • Travel via binding proteins
  • Breakdown products are excreted in the urine or bile
• Water-soluble hormones


  • Polar
  • Include protein hormones, peptide hormones, and aminoacid-derived hormones
  • Some circulate as free hormones (no need for binding proteins)
  • Rapidly degraded by proteases
• Humoral Stimulus


  When the chemicals in the body fluids like electrolytes, sodium, potassium, glucose will be the one to stimulate hormone release.
• Neural Stimulus


  It is when the nerve cell or neurons will stimulate hormone release. If there are neural inputs that is the time that hormone will be released.
• Hormonal Stimulus


  When the hormone stimulates the release of another hormone.
• Decreased Ca levels


  Stimulates Parathyroid Hormone release
• Dehydration


  Stimulates Antidiuretic Hormone (ADH)/Vasopressin release (ADH decreases urine output to conserve water)
• Increased blood glucose levels


  Stimulates Insulin release
• Elevated K levels


  Stimulates Aldosterone release (Aldosterone eliminates K in the urine while conserving Na)
• Low blood pressure


  Stimulates Aldosterone release (which secondarily increases blood volume)
• Neuropeptides


  Responsible for neural regulation of hormone release
• Some neurons secrete their chemical messengers directly into the blood (not into a synaptic cleft)
• These chemical messengers are considered hormones and are called Neuropeptides
• Some specialized neuropeptides stimulate hormone secretion from other endocrine cells
• These are referred to as releasing hormones (usually from the Hypothalamus)
• Tropic hormones


  Hormones that stimulate release of other hormones, usually secreted by the anterior pituitary gland
• Negative Feedback


  May negative effect. Ex: if there is a hormone release nagkakaroon ng negative effect in the body.
• Positive Feedback


  Helps to ovulate and does results to pregnancy: meaning hormone is balanced and is acting upon with the target cells
• Kapag yung signal nag join sa receptor (which is the target cell) nagkakaroon ng effect
• Hormones exhibit specificity for their receptors. Mayroon lang specific hormones para sa specific hormone receptors.
• Kapag yung nag join sa hormone receptors is yung ibang hormones nagkakaroon ng negative effect.
• Hormone can only bind to a receptor specific to it. Ex: Thyroid hormone can only bind to thyroid hormone receptors.
• Characteristics of hormone receptors

  • Specificity
  • Location (internal, external)
  • Regulation number (down regulation, up regulation)