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the endocrine system
works in conjunction with the nervous system to maintain homeostasis. Glands are ductless and secrete their hormones (chemical messages) directly into the blood and have prolonged effects.
classification of hormones: non target
Affect many cells or tissues. Ex growth hormones
classification of hormones: target
tissue specific
classification of hormones: tropic
activate glands to produce hormones. dont have immediate response.
non tropic
have direct results
chemical structure: steroid
Lipids. Can enter the cell. Lasts longer in blood. Hydrophobic
non steroid
Protein. cant go inside the cell.
antagonistic hormones
work against each other. Ex. blood sugar (insulin vs glucagon)
positive feedback
reinforcement increases further results. Ex. oxytocin
negative feedback
non tropic inhibits tropic hormone production. Ex. metabolism (TSH and thyroxine)
hypothalamus
located in the brain. Physical link between nervous and endocrine systems. Produces oxytocin and ADH which are stored in the posterior pituitary. Stimulates the pituitary via releasing hormones. (GnRH)
Pituitary gland
Located in the brain below the hypothalamus. Anterior: FSH, LH, hGH, PRL,ACTH, TSH. Posterior: OCT, ADH
Antidiuretic Hormone (ADH)
released when the osmoreceptors (check how much water is in the body) shrinks (dehydrates) Directly affects water balance. Makes the nephron more permeable to water so that water can be reabsorbed back into the body.
Hyposecretion of ADH
diabetes insipidus.
Thyroid stimulating hormone (TSH)
stimulates the thyroid gland to release its hormones
Adrenocorticotropic hormone (ACTH)
stimulates the adrenal cortex to release hormones (cortisol, aldosterone, testosterone, estrogen)
Human growth hormone (hGH)
stimulates the growth of bones, muscles, and organs by increasing the uptake of amino acids, the metabolism of fats, and rate of cell division.
hyposecretion of hGH
dwarfism
hypersecretion of hGH
gigantism, acromegaly
prolactin (PRL)
causes milk production
oxytocin (OCT)
causes uterine and mammary muscle contraction
follicle stimulating hormone (FSH)
stimulates gametogenesis. stimulates estrogen production
luteinizing hormone (LH)
Females: stimulates ovulation and progesterone production. Males: testosterone production.
the thyroid gland
located in the neck below the larynx. Controlled by TSH which is secreted by the pituitary. Affected by levels of iodine the body. produces thyroxine and calcitonin.
Thyroxin (T4)
regulates metabolic rate by speeding up the rate of cell resp and utilization of glucose and oxygen. Increases the uptake of carbohydrates from small intestine.
Calcitonin
lowers blood calcium levels by stimulating calcium deposition of bones, reduced calcium uptake in intestines and kidneys. Calcium is needed for proper bone, muscle, and nerve functioning as well as blood clotting.
hyperthyroidism
too much thyroid hormones, results in Graves Disease. Weight loss, rapid heartbeat, fatigue, heat intolerance
Hypothyroidism
not enough thyroid hormones produced. Cretinism and goitre.
The parathyroid glands
produces parathyroid hormone (PTH). Antagonistic to calcitonin. Raises blood calcium levels by stimulating the release of Ca from bones, and the reabsorption of Ca in the GI tract and in the kidneys.
the adrenal glands
located on top of each kidney. Outer layer is the cortex which produces aldosterone, cortisol and sex hormones in response to ACTH from the pituitary. Inner layer is the medulla which produces epinephrine in response to the sympathetic nervous system.
aldosterone
increases the movement of Na+ out of the kidney (urine) back into the blood creating an osmotic pull. Increases blood pressure by increasing water retention.
Difference between ADH and Aldosterone
ADH: Makes the nephron more permeable to water so it can be reabsorbed into the body. Regulated by osmotic pressure.
Aldosterone: Increases the movement of sodium out of the kidney, water follows. Regulated by blood pressure.
Cortisol
responds to long term stress. Reduces inflammation and increases the levels of amino acids in the blood which are converted to glucose. (negative feedback)
Epinephrine (adrenaline)
responds to short term stress (flight or fight). Targets the muscles and liver to convert glycogen into glucose. Increases blood to muscles.
Sex hormones
Males: also from testes. Spermatogenesis in testes and 2nd degree sex traits in the body.
Females: estrogen grows endometrium in uterus and 2nd degree sex traits in body. Progesterone: maintain endometrium and inhibits uterine contractions.
pancreas
located below the stomach. Endocrine and exocrine gland because it produces enzymes to digest food, and contains specialized cells known as islets of Langerhans which secrete insulin and glucagon.
insulin
decreases blood glucose levels. makes the cells more permeable to glucose. Increases the conversion of glucose into glycogen in the liver. non target
hyposecretion of insulin
diabetes mellitus (hyperglycemia)
glucagon
antagonistic to insulin. Increases blood glucose levels. Stimulates the breakdown of glycogen to glucose in the liver.
hyposecretion of glucagon
hypoglycemia
hypersecretion of glucagon
hyperglycemia
Type 1 Diabetes
insulin dependant due to the inability to produce insulin. Treatments include insulin injections/pump, pancreas transplantation, Islet transplantation
Type 2 Diabetes (adult onset)
non insulin dependant. Results from the receptors not responding to insulin. Risk factors are diabetes and lack of exercise. Treatment is diet, exercise and drugs.