AP Biology Endocrine Systems
Signal Transduction Pathway
Kinases “turn on” processes Phosphotases “turn off” processes
Basic Hormone Pattern Target effectors Response Simple endocrine pathway Glycogen breakdown, glucose release into blood Liver Blood vessel Pancreas secretes glucagon ( ) Endocrine cell Low blood glucose Receptor protein Stimulus Pathway Example
Remember the “hands” on cell membranes? (In GREEN)
LE 45-7 Mammary glands, uterine muscles Hypothalamus Kidney tubules Oxytocin HORMONE TARGET ADH Posterior pituitary Neurosecretory cells of the hypothalamus Axon Anterior pituitary
Cytokines IL 1 – Macrophage to Helper T IL2 – Helper T to B or Cytotoxic T
Polar versus Non-polar Hormone Signal Reception SECRETORY CELL Hormone molecule Signal receptor VIA BLOOD VIA BLOOD TARGET CELL TARGET CELL Signal transduction pathway OR Cytoplasmic response DNA NUCLEUS Nuclear response Receptor in plasma membraneReceptor in cell nucleus DNA NUCLEUS mRNA Synthesis of specific proteins Signal transduction and response Signal receptor Hormone molecule SECRETORY CELL
Examples of Negative Feedback Loops Hypothalamus TRH Anterior pituitary TSH Thyroid T3T3 T4T4
Positive Feedback Loop
Tropic Hormones of the PosteriorPituitary Mammary glands, uterine muscles Hypothalamus Kidney tubules Oxytocin HORMONE TARGET ADH Posterior pituitary Neurosecretory cells of the hypothalamus Axon Anterior pituitary
Tropic Hormones of the Anterior Pituitary Neurosecretory cells of the hypothalamus Endocrine cells of the anterior pituitary Portal vessels Pituitary hormones (blue dots) Pain receptors in the brain EndorphinGrowth hormone Bones Liver MSH Melanocytes Prolactin Mammary glands ACTH Adrenal cortex TSH Thyroid Testes or ovaries FSH and LH TARGET HORMONE Hypothalamic releasing hormones (red dots) Tropic Effects Only FSH, follicle-stimulating hormone LH, luteinizing hormone TSH, thyroid-stimulating hormone ACTH, adrenocorticotropic hormone Nontropic Effects Only Prolactin MSH, melanocyte-stimulating hormone Endorphin Nontropic and Tropic Effects Growth hormone