45 terms

Endocrine System

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Endocrine system
Coordinates and directs the activity of the body's cells
Endocrinology
The scientific study of hormones and endocrine organs
Hormones
Chemical substances that are secreted by endocrine cells into the extracellular fluids and regulate the metabolic activity of other cells in the body.
Amino acid based
Including protein, peptides, and amines
Molecules/ steroids
Made from cholesterol include sex hormones made by the ovaries and tested and hormones produced in adrenal cortex.
Prostaglandins
Local hormones
Second messenger system
Hormones bind to receptors situated on target cells plasma membrane.
Negative feedback mechanisms
Chief means of regulating blood levels of nearly all hormones
Endocrine gland stimuli
Endocrine organs fall into 3 categories- hormonal, humoral, and neural
Hypothalamus
Part of the nervous system
Pituitary
Major organ of the endocrine system
Thyroid
Major organ of the endocrine system
Parathyroid
Major organ of the endocrine system
Pancreas
Major organ of the endocrine system
Thymus glands
Major organ of the endocrine system
Ductless glands
Produce hormones that they release into the blood or lymph
Pituitary gland
Approximately the size of a pea, hangs by a stalk from the surface of the hypothalamus
Tropic hormones
Stimulate their target organs, to secrets hormones, which turn exert their effects on other body organs and tissues
Growth hormone (GH)
General metabolic hormone, effects directed to growth of skeletal muscles and long bones, plays role in determining body's final size
Pituitary dwarfism
Body proportions are normal but person as a whole is miniature.
Gigantism
Individual becomes externally tall body proportions are normal
Acromegaly
Hypersecretion occurs after lone bone growth ends
Prolactin (PRL)
Protein hormone structurally similar to growth hormone
Adrenocorticitropic hormone (ACTH)
Regulates endocrine activity of the cortex portion of the adrenal gland
Thyroid stimulating hormone (TSH)/ thyroidtropic hormone (TH)
Influences the growth and activity of the thyroid gland
Gonadotropic hormones
Regulate the hormonal activity of the gonads
Gonads
Ovaries and testes
Follicle-stimulating hormone (Fsh)
Stimulates follicle development in the ovaries
Luteinizing hormone (LH)
Triggers ovulation of an egg from the ovary and causes the ruptured follicle to produce progesterone and some estrogen
Sterility
Hyposecreation of FSH or LH
Releasing/ inhibiting hormones
Produced by the hypothalamus
Neurosecretory cells
Transport additional hormones alone the axon of the hypothalamus
Oxytocin
Released in significant amounts only during childbirth and while nursing
Antidiuretic hormone (ADH)
Second hormone released by the posterior pituitary
Vasopressin
Hormones are stored until their release is triggered by nerve impulses from the hypothalamus
Thyroid gland
Hormone producing gland
Follicles
Thyroid gland is composed of hollow structures
Thyroid hormone
Body's major metabolic hormone
Thyroxine
Major hormone secreted by the thyroid follicles
Triiodothyronine
Formed at the target issues by conversion of thyroxine to triiodothyronine
Goiters
Areas with iodine deficient soil that were far from the supply of fresh seafood
Cretinism
Results in dwarfism in where adult body proportions remain childlike hypothyroidism occurring in adults
Myxedema
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Graves' disease
A form of hypothyroidism
Exophthalmos
The thyroid gland enlarges and the eyes may bulge