AP Biology Homeostasis and Development

Signal Transduction Pathway

Kinases “turn on” processes (can amplify) Phosphotases “turn off” processes

Ligand Hormone Target tissue

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

3 parts of hormonal system Exocrine Endocrine Neurosecretory

Remember the “hands” on cell membranes? (In GREEN)

Local Hormones Growth factors Nitric Oxide (NO) Prostaglandins Cytokines

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

Most of the cells in the thyroid are called follicular cells, but there are others called parafollicular cells (or C cells) which produce another important hormone called calcitonin. The thyroid also has four teensy glands called the parathyroid glands, which are embedded in the back of the thyroid and produce the hormone creatively called parathyroid hormone. These two hormones, calcitonin and parathyroid hormone, work in tandem to keep your body's calcium level in check. We all know how important calcium is to prevent diseases like osteoporosis, but too much of a good thing isn't ideal either. That's where calcitonin comes in; it decreases how much calcium is in your blood, while parathyroid hormone works to beef those levels up.calcium