Presentation on theme: "Chapter 9: The endocrine system"— Presentation transcript:
1 Chapter 9: The endocrine system Bio 24what is the endocrine system?
2 The endocrine system One of two communication systems in the body Consists of hormones: chemicals secreted into the blood that travel throughout the body to act on specific target cellsOnly cells with the appropriate receptors will respond to the hormonal signal
3 Functions of the endocrine system Hormones are essential for:reproductionregulation of the immune systemutilization of energymaintenance of bone and muscle massgrowthregulation of salt and water balance and blood pressureregulation of our moods & emotionsmany other things!
4 The endocrine vs. the nervous system Endocrine systemuses chemical signalschemical signals secreted into the bloodeffects take minutes or hours and may be long-lastingNervous systemuses chemical and electrical signalschemical signals travel only across a synapseeffects take a fraction of a second and usually mediates rapid responses
5 2 main categories of hormones Amino acid-based hormones (most common) include proteins, peptides, and amino acid derivativesInclude insulin, growth hormone, thyroid hormonesSteroid hormones are small lipid molecules made from cholesterol that can cross cell membranesInclude testosterone, estrogen, progesterone, and cortisol
12 Endocrine organsMost hormones are released from epithelial cells that form endocrine glandsMajor ones are shown here
13 The hypothalamus is the master controller through the pituitary glands Tropic hormones from H control hormone release from pituitary gland
14 Hormones of the anterior pituitary: growth hormone Growth hormone promotes growth of bones and muscles in children, and maintenance of muscle mass in adultsGrowth hormone excess can result in gigantism (if in childhood) or acromegaly (if in adulthood)
15 Hormones of the anterior pituitary: prolactin Stimulates and maintains milk productionMen make it, too, but function is unknown!
16 Hormones of the anterior pituitary: adrenocorticotropic hormone (ACTH) ACTH is a tropic hormone that regulates the activity of part of the adrenal glands called the adrenal cortexGlucocorticoids released from the adrenal cortex increase blood glucose and are involved in our stress response; mineralocorticoids regulate salt and water balance by controlling urine composition
17 Hormones of the anterior pituitary: follicle-stimulating hormone (FSH) and luteinizing hormone (LH) Both these hormones control the hormonal activity of the gonads: testes and ovariesBoth are essential for the development of both sperm and eggs
18 Hormones of the anterior pituitary: Thyroid-stimulating hormone (TSH) TSH influences the growth of and hormone release from the thyroid glandThe thyroid gland releases thyroid hormones, which contain amino acid-like molecules bound to iodine atoms and also calcitonin, which regulates calcium deposition in bones
19 Structure of the thyroid colloid is what thyroid hormones are made of
20 Thyroid hormone targets Thyroid hormones act on essentially every cell in the bodyControl metabolic rate and energy utilizationAlso important for normal growth and development and reproductive functionThyroid disease is quite common!
21 Thyroid deficiencyHypothyroidism (underactive thyroid) is most often caused by autoimmune disease that attacks the thyroidSymptoms include fatigue, persistent feeling of cold, bloating and weight gain, dry skin, and mental slownessCan be very well treated by taking thyroid hormone pillsThyroid deficiency in children can cause mental retardation and dwarfism, known as cretinism
22 Thyroid excessHyperthyroidism (overactive thyroid) can also result from autoimmune disease or a benign tumor of the thyroidGraves’ disease is one form of hyperthyroidism that also causes exophthalmos (bulging eyes)Symptoms include rapid heart rate, heat intolerance, and nervous behaviorHyperthyroidism is harder to treat
23 Goiter A goiter is an enlarged thyroid Can be caused by hyperthyroidism or hypothyroidismTraditionally caused by dietary iodine deficiency