AP Biology Endocrine System Hormones

AP Biology  Why are hormones needed?  chemical messages from one body part to another  communication needed to coordinate whole body  daily homeostasis & regulation of large scale changes  solute levels in blood  glucose, Ca ++, salts, etc.  metabolism  growth  development  maturation  reproduction Regulation growth hormones

AP Biology Regulation & Communication  Animals rely on 2 systems for regulation  endocrine system  system of ductless glands  secrete chemical signals directly into blood  chemical travels to target tissue  target cells have receptor proteins  slow, long-lasting response  nervous system  system of neurons  transmits “electrical” signal & release neurotransmitters to target tissue  fast, short-lasting response

AP Biology Regulation by chemical messengers axon endocrine gland receptor proteins target cell  Neurotransmitters released by neurons  Hormones release by endocrine glands receptor proteins hormone carried by blood neurotransmitter Lock & Key system

AP Biology Classes of Hormones  Protein-based hormones  polypeptides  small proteins: insulin, ADH  glycoproteins  large proteins + carbohydrate: FSH, LH  amines  modified amino acids: epinephrine, melatonin  Lipid-based hormones  steroids  modified cholesterol: sex hormones, aldosterone insulin

AP Biology Major Glands and their hormones  Hypothalamus: integrates the nervous and endocrine systems  Posterior Pituitary: secretes oxytocin (uterine contractions) and antidiuretic hormone (ADH, water/salt balance)  Anterior Pituitary: growth hormones, LH & FSH (reproduction)

AP Biology Major glands  Thyroid gland: regulates metabolism and calcium in the blood  Parathyroid: calcium in the blood  Pancreas: insulin and glucagon (blood sugar)  Adrenal Glands: epinephrine and norepinephrine (increase metabolism); steroids that regulate blood

AP Biology Major glands  Testes: androgens (steroids for sperm and male sex characteristics)  Ovaries: estrogen and progesterone (menstruation, pregnancy, and female sex characteristics)  Pineal gland: melatonin (sleep cycles)

AP Biology Diabetes  Diabetes is an endocrine system disorder, caused by a deficiency of insulin or a decreased response to insulin in target tissues, resulting in high blood glucose levels.  In the pancreas, cells called islets of Langerhans secrete glucagon and insulin, which regulate glucose in the blood.  Insulin lowers blood glucose levels.  Type I: hereditary, Type II: diet