Flashcards in Exam 4: Endocrine System Deck (28)
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Endocrine gland
-secretes hormones into bloodstream.
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Hormone
-chemical messenger that regulates activity of other body cells.
-hormone levles constantly adjusted by feedback loops.
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Negative Feedback Loop
-a stimulus causes an endocrine organ to release hormones
-the hormone helps bring the body back to homeostasis
-once homestasis is achieved, the hormone release stops
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Endocrine System
-all endocrine glands in body
-overseen by hypothamus
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Hypothalamus' Control (3 Ways)
-produces regulatory hormones that stimulate or inhibit anterior pituitary hormone secretion
-produces ADH and oxytocin and are stored in posterior pituitary
-oversees ANS, stimulates hormone secretion of adrenal medulla via sympathetic innervation
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Pituitary Gland
-connected to hypothalums via infundibulum
-split into anterior and posterior
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Posterior Pituitary
-axons from hypothalamus cells
-stores two hormones produced by hypothalamus: oxytocin and ADH
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Oxytocin
-cuddling/trust hormone
-stimulates uterine contractions/ induces labor (menstrual cramps)
-stimulates breast milk release in response to suckling infant
-males: stimulates smooth muscle contraction in reproductive tract
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ADH
-diuresis = urine production
-inhibits urine formation/production
-concentrates urine
-ADH targets the kidneys and blood vessels
-secreted when dehydrated
-tells kidneys to concentrate urine by reabsorbing more water
-blood vessels constrict to increase blood pressure
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Anterior Pituitary
-VP of endocrine system, controlled by hypothalamus
-controls growth hormone (GH), thyroid stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), follicle stimulating hormone (FSH), luteinizing hormone (LH), and prolactin (PRL)
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Growth Hormone (GH)
-stimulates cell growth and mitosis in most cells
-especially affects skeletal and muscular systems, and adipose tissue
-anterior pituitary-->secretes GH-->targets muscle, bone, fat
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Thyroid Stimulating Hormone (TSH)
-targets thyroid gland
-stimulates thyroid to produce/release its own hormones
-anterior pituitary-->secretes TSH-->targets thyroid gland-->secretes TH
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Adrenocorticotropic Hormone (ACTH)
- target organ: adrenal cortex
-stimulates adrenal cortex to release its hormones
-anterior pituitary-->secretes ACT-->adrenal cortex-->secretes hormones
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Follicle Stimulation Hormone (FSH)
-target organs: ovaries and testes
-anterior pituitary-->secretes FSH-->targets onads
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Luteinizing Hormone (LH)
-target organs: ovaries and testes
-anterior pituitary-->secretes LH-->targets gonads
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Prolactin (PRL)
-target organs: mammary glands
-stimulates breast milk production
-anterior pituitary-->secretes PRL-->targets mammary glands
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Thyroid Gland
-anterior to trachea and inferior to larynx
-secretes thyroid hormone (TH) anad calcitonin
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Thyroid Hormone (TH)
-increases cellular activity (metabolic rate) in most cells of body
-hypothalamus-->anterior pituitary-->secretes TSH-->targets thyroid gland-->secretes TH
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Calcitonin
-encourages deposition of calcium from bloodstream into bone tissue
-secreted when blood calcium levels are high
-lowers blood calcium levels
-increases bone deposition
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Parathyroid Glands
-4 tiny oval masses behind thyroid
-secrete parathyroid hormone (PTH) when blood calcium levels are low
-increases blood calcium levels
-stimulates osteoclasts to resorb bone, release calcium into blood
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Adrenal Glands
-superior to kidneys
-have outer cortex and inner medulla
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Adrenal Cortex
-releases corticosteroids in response to ACTH
-one group of these steroids: controls balance of sodium (Na+) and potassium (K+) ions in body fluids (regulates salt)
-another (2nd) group of steroids stimulates metabolism of glucose from fats and proteins (regulates blood sugar levels)
-another (3rd) group of these steroids: secretes small amounts of androgens (male sex hormones)
-in females, some androgens are converted to estrogen (regulates sex)
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Adrenal Medulla
-stimulated by sympathetic division of ANS
-secretes epinephrine and norepinephrine
-prolongs "fight or fligh" response by sympathetic innervation
-hypothalamus-->sympathetic innervation-->adrenal medulla-->epinephrine and norepinephrine
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Pancreas
-has both exocrine and endocrine functions
-exocrine functions were discussed w/digestive system
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Pancreatic Islets
-produces hormones
-Insulin and glucagon
-helps convert some glucose into glycogen (a carbohydrate)
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Insulin
-lowers blood sugar (glucose) levels, enhances cells ability to pick up glucose
-secreted when you eat a meal
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Glucagon
-raises blood sugar levels
-breaks down glycogen into glucose
-secreted when you haven't eaten in a while
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