A Level Biology - Module 5, Chapter 14: Hormonal communication

• HORMONE: chemical messengers secreted by a gland when it is triggered, another hormone or neurone gernerates signals the gland
• INSULIN: hormone that reduces blood sugar levels by converting glucose into gluycogen
• ADRENALINE: hormone that is produce in a flight or fight response: increases heart rate, dilates pupils, increases blood glucose levels
• Triggered gland > hormonal secretion > hormone transported in blood plasma > bind to receptors on target cells > stimulate a response
• STEROID HORMONE: are lipid soluble so can bind to receptors in the cytoplasm as can diffuse through the phospholipid bilayer, form a hormone-receptor complex, this is a transcription factor and can facilitate or inhibit genes
• NON-STEROID HORMONES: hydrophillic so cannot pass through cell surface membrane, bind to receptors on cell surface then trigger a secondary messenger to form a response inside the cell

• ENDOCRINE GLANDS: secrete hormones directly into the blood: pituitary gland, thymus, thyroid, adrenal glands, pancreas, testis, ovarys
• EXOCRINE GLANDS: secrete chemicals into a duct which travels to an organ ir skin surface: sweat glands, bile duct
• ADRENAL GLANDS: located ontop of each kidney and produce adrenaline. Split into a cortex (which produces glucocorticoids to regulate metabolism and blood pressure and a small amount of sex hormones) and a medulla (whoch produces adrenaline and noradrenaline)
  
• PANCREAS: is both and exo and endocrine gland, Exocrine gland produces digestive enzymes (amylayses, proteases and lipases) that flow from a duct into the small intestine whilst the edocrine gland produces insulin (B cells) and glucagon (a cells) in the Islet of Langerhan
  

• GLUCOSE: soluble molecule that is transported in the blood and is used in cellular respiration
• GLYCOGEN: multibranched polysaccaride of glucose and is a form of energy storage
• GLUCAGON: peptide hormone that is produced by a cells in response to low blood glucose levels

Increase glucose levels:

• GLUCONEOGENESIS: production of glucose from non-carbohydrate sources
• GLYCOGENOLYSIS: breaking down of glycogen into glucose in response to low blood glucose levels

Decrease glucose levels

• GLYCOGENESIS: prouction of glycogen from glucose
• Insulin production
  

• HYPERGLYCEAMIA: too much glucose
• HYPOGLYCEAMIA: too little glucose

• DIABETES: the inability to respond or produce insulin
• TYPE 1 DIABETES: when your body doesn't produce insulin due to B cells not responding to rising glucose levels. Can be an autoimmune response when B cells are being destroyed by immune system. Controlled by insulin injections
• TYPE 2 DIABETES: when your body cannot respond to insulin production.Controlled by regulating diet and excercise
• INSULIN SECRETION: K+ channels are open and K+ ions flow out of the cell leaving the cell charged at -70mV > glucose enters the cell via a transporter > glucose metabloised by glucokianase to form ATP > ATP closes K+ channels causing depolarisation to -30Mv > Ca2+ channels open due to depolarisation and Ca2+ ions enter cell > Ca2+ ions causes vesicles to secrete insulin
• INSULIN: globular protein made from 51 amino acids in 2 polypeptide chains
• GLUCOKIANASE: converts glucose into ATP using PHOSPHORYLATION

• ADRENALINE: hormone secreted by the adrenal glands in response to danger. Increases heart rate, dilates pupils, increases breathing, stops gut function, increases glucose levels
• ACTH: hormone that signals for other hormones to be released as a response
• Threat detected by AUTONOMIC SYSTEM > HYPOTHALAMUS sends signals to SYMPATHETIC NERVOUS SYSTEM > either: uses neurones to stimulate a response or uses ADRENAL CORTICAL SYSTEM to release hormones > response
• ADRENALINE: first messenger
• cAMP: secondary messenger
• To increase glucose levels in response to threat: adenaline binds to receptor site on cell > ADENYL CYCLASE enzyme is activated > enzymeconverts ATP to cAMP > cAMP activates protein kinases which phosphorylate other enzymes > other enzymes convert glycogen to glucose