Flashcards in Chapter 19- Endocrine System Deck (35)
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1
general characteristics
-chronic regulation of homeostasis
--slow and prolonged responses
--acute=nervous system
-interrelated with nercous system
--hypothalamus and posterior pituitary
-ductless system
--hormones produced by specialized cells
--carried in blood stream
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hormones
-substance synthesized by a specific organ or tissue and secreted:
--secreted into extracellular spaces=paracrine signaling (no blood needed)
--blood carries it to other sites=endocrine signaling
-act on target cells
--have specific receptors for specific hormones
3
chemistry of hormones: categories
1. steroids: made from cholesterol, non polar
2. peptides: polar
3. amines
-derived from amino acids
-polar and non-polar
4. eicosanoids
-most are non-polar
-paracrine signals (prostaglandins)
4
steroid hormones
-lipid soluble therefore can cross cell membrane
--transduction=regulation of DNA transcription
-examples
--estrogens like estradiol
--androgens like testosterone
--aldosterone
--cortisol
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amine hormones
-derived from either tyrosine or tryptophan
-some are membrane soluble (thyroxine)
-some are not (epinephrine)
-most important ones are made by:
--thyroid
--adrenal medulla
6
other hormones
peptide hormones
-short chains of amino acids
--cannot cross cell membrane
-all pituitary hormones
eicosanoids
-derived from fatty acids
--most cross cell membranes
-coordinate functions in extracellular fluid
--ex. prostaglandins
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control of hormone secretion
negative feedback
-gland is sensitive to concentration of substance
-concentration exceeds limits--> prevents gland from secreting hormone
-concentration decreases->secretion increases
-results in relatively stable concentration of both substance and hormone
8
hypothalamus
-sends signals to the body and the pituitary gland
--really 2 separate glands: developmental origins are key to function
-pituitary is the most important endocrine gland for regulation
-basically runs endocrine system
9
pituitary gland
2 lobes
posterior (neural)
-does not make any hormones
-mostly hypothalamic axons
anterior (endocrine)
-5 types of endocrine cells
-controlled by hypothalamic regulatory hormones
--releasing hormones
--inhibiting hormones
10
posterior pituitary hormones
Oxytocin
ADH
11
oxytocin
-posterior pituitary
-causes contraction of muscles in uterine walls
-causes muscles associated with milk ejection to contract
-cause contraction of prostate gland
-significant in emotional bonding
--familial
--romantic
does NOT make milk, just causes release
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antidiuretic hormone
-causes kidney to decrease water excetion
-increases blood volume-> rise in BP
13
anterior pituitary hormones
1. melanocyte stimulating hormone (MSH)
2. follicle stimulating hormone (FSH)
3. luteinizing hormone (LH)
4. growth hormone (GH)
5. thyroid stimulating hormone (TSH)
6. prolactin (PRL)
7. adrenocorticotropic hormone (ACTH)
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melanocyte stimulating hormone
-increases melanin secretion
15
follicle stimulating hormone
-testes to produce sperm
-follicular development in ovary
-stimulate secretion of estrogen
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luteinizing hormone
-promotes secretion of sex hormones
-release of oocyte
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growth hormone
-GH
-increase size and rate of reproduction of body cells
-targets muscles and bones-mobilizes fat and glucose
-enhances movement of amino acids through membranes
-secreted throughout life, increases at puberty
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thyroid stimulating hormone
-TSH
-controls secretion of thyroid hormone
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prolactin
-PRL
-targets mammary tissue
-milk production/secretion
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Adrenocorticotropic hormone
-ACTH
-stimulates adrenal cortex to produce corticosteroids
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thyroid gland
-2 lobes and isthmus
--inferior to larynx
-Follicular cells
--line follicle cavities (filled with thyoglogulin colloid)
--remove Iodine from blood
--secrete T3 and T4
-Parafollicular cells
--produce calcitonin
22
thyroid hormones: follicular cells
Thyroxine (T4)
-increase glycogenolysis
-increase protein synthesis
-increase growth
Triiodothyronine (T3)
-same as T4 but 5x's more potent
23
thyroid hormones: parafollicular cells
calcitonin
-DECREASE blood calcium and phosphate
-increase renal excretion
-increase osteoblast activity
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parathyroid glands
posterior surface of thyroid
-many tightly packed secretory cells
--oxyphil and transitional cells=immature
--chief cells=produce parathyroid hormone
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parathyroid hormones
parathyroid hormone (PTH)
-INCREASE blood calcium
-decrease renal calcium and phosphate excretion
-increase osteoclast activity
-increase calcitriol=intestinal calcium absorption
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thymus
thoracic cavity, posterior to sternum
-produces thymosin
--enhances lymphocyte production and competence
--most active in infancy and childhood
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adrenal glands
adrenal cortex
adrenal medulla
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adrenal cortex
-glomerulosa
--aldosterone: sodium retention
-fasciculata
--cortisol: glycogen formation
-reticularis
--androgens: secondary sexual characters
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adrenal medulla
-chromaffin cells which are modified postganglionic cells of the SNS (neurons)
--epinephrine and norepinephrine
-only gland directly stimulated from brain
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kidneys
-renin: start cascade to increase blood pressure
-erythropoietin (EPO): erythrocyte production
-calcitriol: increases absorption of digested calcium
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heart
atrial natriuretic peptide (ANP)
-suppresses aldosterone and ADH
-decrease blood volume and blood pressure
32
pancrease
posterior to stomach
-attaached to duodenum by duct
-exocrine and endocrine function
islets of langerhans=endocrine function
-alpha cells
--glucagon=increases blood sugar
-beta cells
--insulin= decreases blood sugar
-delta cells
--somatostatin: inhibits glucagon and insulin secretion
--antagonizes GH
33
male gonads
interstitial cells
-secrete androgens
--testosterone
---stimulate nurse cells
---secondary sex characteristics
nurse cells
-secrete inhibin
--decrease FSH from anterior pituitary
--stimulate spermatogenesis
34
female gonads
follicles=pre-ovulation
-estrogens:
--maturation of oocyte
-- endometrial development
-inhibin:
--decrease FSH from anterior pituitary
corpus luteum: post-ovulation
-estrogens (estradiol)
-progesterone
--prepares body for pregnancy
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