NOTES 11.5: ENDOCRINE SYSTEM. Pages

Transcription

1 NOTES 11.5: ENDOCRINE SYSTEM Pages

2 ENDOCRINE SYSTEM Communication system that controls metabolism, growth, and development with hormones Maintains homeostasis Hormones: chemical messengers released from glands that act on target cells Glands: organs that secrete hormones

3 ENDOCRINE SYSTEM Relies on circulatory system to send chemical messages

4 TYPES OF HORMONES Steroid hormones (non-polar): diffuse through cell membrane to bind to a protein which starts gene expression Amino acid-based hormones (polar): first messenger binds to cell surface receptor causing second messenger inside the cell to initiate cell activity

5 REVIEW OF FEEDBACK MECHANISMS Process that uses the conditions of one component to regulate the function of the other Part of a chain of cause-and-effect that forms a circuit or loop

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7 REVIEW OF FEEDBACK MECHANISMS Negative feedback: the product (response) stops production of the initial stimulus to bring back to normal Positive feedback: the product stimulates production (amplify) of the initial stimulating substance or action until the stimulus or change is gone

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9 ENDOCRINE ORGANS

10 ENDOCRINE ORGANS Pituitary Gland Produces hormones that affect other glands (thyroid, gonads, adrenal glands) Controls growth, metabolism, sexual development, and reproduction Known as master gland

11 ENDOCRINE ORGANS Growth hormone or GH - GH stimulates growth in childhood and is important for maintaining a healthy body composition. In adults it is also important for maintaining muscle mass and bone mass. It can affect fat distribution in the body. Adrenocorticotropin or ACTH - ACTH stimulates production of cortisol by the adrenal glands. Cortisol, a so-called "stress hormone," is vital to survival. It helps maintain blood pressure and blood glucose levels. Thyroid-stimulating hormone or TSH - TSH stimulates the thyroid gland to make thyroid hormones, which, in turn, control (regulate) the body's metabolism, energy, growth and development, and nervous system activity. Luteinizing hormone or LH - LH regulates testosterone in men and estrogen in women. (gonadotropin) Follicle-stimulating hormone or FSH - FSH promotes sperm production in men and stimulates the ovaries to release eggs (ovulate) in women. LH and FSH work together to allow normal function of the ovaries or testes. (gonadotropin) Oxytocin - Oxytocin causes milk letdown in nursing mothers and contractions during childbirth. Antidiuretic hormone or ADH - ADH, also called vasopressin, is stored in the back part of the pituitary gland and regulates water balance. If this hormone is not secreted properly, this can lead to problems of sodium (salt) and water balance, and could also affect the kidneys so that they do not work as well.

12 ENDOCRINE ORGANS Thyroid Regulates metabolism, growth, and development

13 ENDOCRINE ORGANS Adrenal glands Produces adrenaline (immediate stress) and cortisol (long-term stress) Responds to stress

14 ENDOCRINE ORGANS Thymus Stimulate formation of T-cells (immune cells)

15 ENDOCRINE ORGANS Gonads (ovaries and testes) Produce sex hormones to regulate secondary sex characteristics and reproduction

16 ENDOCRINE ORGANS Pancreas Produces insulin when blood glucose is high Beta cells of the pancreas secrete insulin, which signal fat cells or the liver to take up the glucose and store it as glycogen Produces glucagon when blood glucose is low Alpha cells of the pancreas secrete glucagon to signal the liver to break down glycogen to release glucose Regulates blood sugar levels

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18 DIABETES A person has elevated blood glucose levels because cells do not take in the glucose and glucose is a toxin to the body in high quantities Type I diabetes (insulin-dependent): Autoimmune disorder in which the immune system destroys pancreatic beta cells that produce insulin; therefore, insulin is not produced Type II diabetes (non-insulin-dependent): Reduced response due to change in insulin receptors from overuse

19 NERVOUS SYSTEM VS ENDOCRINE SYSTEM Nervous System Endocrine System Signals Mode of transmission/transport Nerve impulses (electrical) Transmitted by neurons Hormones (chemicals) Transported by blood Speed Fast Slow Connectedness Highly connected Disconnected