Animation 1 Action of Epinephrine on a Liver Cell Epinephrine water soluble hydrophilic cannot enter liver cell hydrophobic Binds to receptor activates G protein G protein subunit dissociates carrying GDP changes to GTP Subunit attaches to adenylyl cyclase activates cAMP forms binds to protein kinase A adds phosphate groups to specific cellular proteins PKA activates phosphorylase glycogen glucose 6 phosphate glucose Epinephrine causes liver to secrete glucose into blood during fight or flight Animation 2 Blood Sugar Regulation in Diabetics Insulin signals muscle and liver cells to take up glucose from blood returning blood sugar to normal Type I diabetes no insulin release blood sugar remains high o Treatment artificial insulin release Type II diabetes insulin released but cells do not receive the signal o Treatment increase cell sensitivity or block liver synthesis of glucose Animation 3 Bone Growth in Width Bone growth appositional new bone form on surface of old Osteoblasts form bone around blood vessels tunnels form and concentric lamellae fill tunnels to complete new osteon Animation 4 Action of Glucocorticoid Hormone Glucocorticoid hormones steroidal influence nutrient metabolism o Activate genes for proteins involved with glucose synthesis protein breakdown and fat mobilization Enter cell through transporters bind to receptors activate genes release proteins Receptor dimers forms enter nucleus bind to DNA sequence GREs near target genes GREs are enhancers activate transcription of target gene Animation 5 Hormonal Communication Hypothalamus detects problem directed to posterior pituitary gland hormone released Hormone target cells binds to receptors triggers change Ex dehydration o Antidiuretic hormone ADH released travels through blood and kidney o Kidney reduces urine volume output increasing water retention to counter dehydration o Blood vessels vasoconstriction increased higher BP to counter BP drop Animation 6 Hormones and Gastric Secretion Taste smell touch though of food send impulses to the brain o Hydrochloric acid and pepsin secreted in the stomach o Gastrin secreted in lower stomach enters blood stream and increases hydrochloric acid Food enters stomach distention signal to brain and gastric glands continued secretion of hydrochloric acid and pepsin Chyme contains lipids and decreases pH to below 2 inhibiting gastric secretion by o Impulses to the brain decrease stimulation of gastric glands o Set up local reflexes via neurons in gut wall to decrease gastric secretion o Cause release of local hormones secretin to gastric glands to inhibit secretion Animation 7 How Intracellular Receptors Regulation Gene Transcription Intracellular receptors can trigger variety of responses such as regulators of gene transcription Receptors have DNA binding site o Inactive state receptor cannot bind to DNA inhibitor protein occupies binding site Signal molecule binds to another site on receptor inhibitor release DNA binding site exposed receptor enters nucleus binds to nucleotide sequence activates specific gene transcription adjacent to regulatory site Target cell s response depends on nature of cell Animation 8 Hydrochloric Acid Production by Parietal Cells in the Gastric Glands of the Stomach Carbonic anhydrase catalyzes reaction between CO2 and water to form carbonic acid o Carbonic acid bicarbonate ion hydrogen ion bicarbonate ion into bloodstream chloride ion into parietal cell Hydrogen ions enter into gastric gland ducts negative chloride ions diffuse with positive hydrogen ions Potassium ions counter transported into parietal cell in exchange for hydrogen ions Net result hydrochloric acid in parietal cells secrete duct of gastric gland Animation 9 Intracellular Receptor Model Aldosterone lipid soluble easily diffuses through plasma membrane Binds with receptor in cytoplasm complex moves into nucleus binds to DNA stimulate synthesis of messenger RNA mRNA leaves nucleus to cytoplasm binds to ribosomes to direct protein synthesis produce response of cell to aldosterone Animation 10 Maturation of the Follicle and Oocyte Animation 11 Mechanism of Action of Lipid Soluble Messengers file C Users Bridgette AppData Local Temp Temp1 17 animations videos zip Mechanism of Action of Lipid Soluble Messengers swf Lipid soluble messenger enters target nucleus to specific receptor binds to DNA mRNA released from nucleus protein synthesis altered functional response Animation 12 Mechanism of Steroid Hormone Action Steroid hormones are not water soluble travel in blood attached to protein carriers Some enter to cytoplasm bind to receptor and complex moves to nucleus Others travel directly ton nucleus before encountering receptor proteins Hormone receptor protein is activated by bind to hormone can bind to DNA regions known as Hormone receptor complex effects transcription at that site mRNA produced and codes for hormone response elements synthesis of specific proteins Animation 13 Mechanism of Thyroxine Action Thyroxine T4 water soluble hormone brought to cell via protein carrier lipophilic easily diffuses T4 T3 Only T3 enters nucleus and binds to nuclear receptor proteins Hormone receptor protein complex binds to hormone response elements on DNA mRNA produced codes for specific proteins Binding of hormone receptor complex has direct effect on level of transcription at binding site Animation 14 Membrane Bound Receptors G Proteins and Ca2 Channels Ligand binds to receptor outside cell membrane G protein attached to alpha unit changes guanosine diphosphate guanosine triphosphate on subunit and alpha unit detaches from beta and gamma Alpha binds to calcium ion channel which opens Calcium enters cell and combine with calmodulin produces response of cell to the ligand A phosphate is removed from guanosine triphosphate inactivating alpha subunit which separates from calcium ion channel closes Alpha recombines with gamma and beta subunits G protein recombines with receptor Animation 15 Mitosis Animation 16 Osmosis Membrane permeable to solute and water o More solute on right shifts left in exchange for water o Equilibrium equal concentration and volume Membrane permeable only to water o More solute on right more water on left o Equilibrium equal concentrations more volume on right Animation 17 Peptide Hormone Action Peptide hormones do not enter cell bind to receptor on target cell s plasma membrane Example epinephrine from adrenal medulla bind to receptor on liver cell o Breaks down glycogen to