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endocrine system/Leslie Vieyra p. 2 - Coggle Diagram
endocrine system/Leslie Vieyra p. 2
major functions of the endocrine system:
works with the nervous system to maintain homeostasis
secretes hormones that control mood, metabolism, growth, and development into body fluids
regulates all biological processes in the body from conception through adulthood and into old age
major endocrine/organ glands and their functions
pituitary gland:Through secretion of its hormones, the pituitary gland controls metabolism, growth, sexual maturation, reproduction, blood pressure a
thyroid gland: below Adam's apple, produces T3 and T4, helps to regulate many body functions by constantly releasing a steady amount of thyroid hormones into the bloodstream.
parathyroid gland: lies behind the thyroid glands in the neck, produces parathyroid hormones which increases levels of calcium in blood
adrenal glands: located on top of both kidneys, composed of cortex and medulla, produce hormones that help regulate your metabolism, immune system, blood pressure, response to stress
pancreas: digests food, and manages use of sugar for energy after digestion
pineal gland:found in vertebrates that is the source of melatonin, a hormone derived from tryptophan that plays a central role in the regulation of circadian rhythm :
reproductive glands: The gonads, the primary reproductive organs, are the testes in the male and the ovaries in the female, produces sex hormones of an organism
kidneys: removes waste and toxins, excess water from the bloodstream, which is carried out of the body in urine.
thymus glands: makes white blood cells, produces T cells, affects immune system
steroid vs nonsteroid
non steroid hormones
combine with receptors in target cell membranes; the
receptors have a binding site and an activity site
The hormone is called the first messenger
ex: norepinephrine, dopamine, serotonin and epinephrine.
The chemicals in the cell that respond to binding of the hormone, and cause
changes in the cell, are called second messengers
steroid hormones:
Steroid hormones are lipid-soluble, so they can pass through cell
membranes
Carried in the bloodstream weakly bound to plasma proteins
ex:glucocorticoids, mineralocorticoids, androgens, oestrogens and progestogens.
diseases associated with the endocrine system
thyroid disorders:
hypothyroidism: underactivity of the thyroid gland, causes low metabolic rate, can cause cretinism in infants
hyperthyroidism: overactivity of the thyroid gland, causes high metabolic rate, can lead to eye protrusion
parathyroid hormone disorders:
Hypoparathyroidism: deficiency of PTH, due to surgical removal
or injury to glands, decrease in blood calcium
Hyperparathyroidism: excess of PTH, perhaps due to
parathyroid tumor, which results in an increase in blood calcium
disorders of adrenal hormones:
Addison disease: hyposecretion of glucocorticoids and
mineralocorticoids
Cushing syndrome: hypersecretion of adrenal cortical
hormones
growth hormone imbalances:
pituitary dwarfism: due to GH deficency during childhood
gigantism: Due to GH over secretion during childhood
acromegaly: due to over secretion in adult hood
homeostatic mechanisms of hormone regulation (negative and positive feedback)
negative feedback: negative feedback mechanisms control hormone release
In a negative feedback system, a gland is sensitive to the concentration
of the substance it regulates
control mechanisms:
Release of hormones from the hypothalamus controls secretions of the anterior pituitary, and anterior pituitary hormones affect the activity of other endocrine glands
The nervous system influences certain endocrine glands directly
Other glands respond directly to changes in the internal fluid
composition
positive feedback:
positive feedback:When the concentration of the hormone then drops below its normal level, the inhibition is removed, and the gland begins secreting more