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2 - Keiser A&P 2 > 0-1 Chapter 17 - Endocrine System > Flashcards

0-1 Chapter 17 - Endocrine System Flashcards

1
Q

four principal mechanisms of communication between cells

A

gap junctions
neurotransmitters
paracrine (local) hormones
Hormones

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2
Q

gap junctions

A

pores in cell membrane allow signaling molecules, nutrients, and electrolytes to move from cell to cell

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3
Q

neurotransmitters

A

released from neurons to travel across synaptic cleft to second cell

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4
Q

paracrine (local) hormones

A

secreted into tissue fluids to affect nearby cells

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5
Q

hormones

A

chemical messengers that travel in the bloodstream to other tissues and organs

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6
Q

endocrine system

A

glands, tissues, and cells that secrete hormones

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7
Q

endocrinology

A

the study of this system and the diagnosis and treatment of its disorders

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8
Q

endocrine glands

A

organs that are traditional sources of hormones

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9
Q

hormones

A

chemical messengers that are transported by the bloodstream and stimulate physiological responses in cells of another tissue or organ, often a considerable distance away

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10
Q

major organs of endocrine system

A 
pineal gland
hypothalamus
pituitary gland
thyroid gland
thymus
adrenal gland
pancreas
parathyroid gland
gonads
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11
Q

exocrine glands

A

–have ducts carry secretion to an epithelial surface or the mucosa of the digestive tract –‘external secretions’
–extracellular effects (food digestion)

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12
Q

endocrine glands

A

–no ducts
–contain dense, fenestrated capillary networks which allows easy uptake of hormones into bloodstream
–‘internal secretions’
–intracellular effects such as altering target cell metabolism

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13
Q

liver cells defy rigid classification

A

releases hormones, releases bile into ducts, releases albumin and blood-clotting factors into blood (not hormones)

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14
Q

Comparison of Nervous and Endocrine Systems (Differences)

both serve for internal communication

A

–nervous -both electrical and chemical

–endocrine -only chemical

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15
Q

Comparison of Nervous and Endocrine Systems (Differences)

speed and persistence of response

A

–nervous -reacts quickly (1 -10 msec), stops quickly

–endocrine -reacts slowly (hormone release in seconds or days), effect may continue for weeks

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16
Q

Comparison of Nervous and Endocrine Systems (Differences)

adaptation to long-term stimuli

A

–nervous -response declines (adapts quickly)

–endocrine -response persists (adapts slowly)

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17
Q

Comparison of Nervous and Endocrine Systems (Differences)

area of effect

A

–nervous -targeted and specific (one organ)

–endocrine -general, widespread effects (many organs)

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18
Q

Nervous and Endocrine Systems (Similarities)

several chemicals function as both hormones and neurotransmitters

A

–norepinephrine, cholecystokinin, thyrotropin-releasing hormone, dopamine and antidiuretic hormone

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19
Q

Nervous and Endocrine Systems (Similarities)

some hormones secreted by neuroendocrine cells

A

(neurons) that release their secretion into the bloodstream

–oxytocin and catecholamines

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20
Q

Nervous and Endocrine Systems (Similarities)

both systems with overlapping effects on same target cells

A

–norepinephrine and glucagon cause glycogen hydrolysis in liver

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21
Q

Nervous and Endocrine Systems (Similarities)

systems regulate each other

A

–neurons trigger hormone secretion

–hormones stimulate or inhibit neurons

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22
Q

target organs or cells

A

those organs or cells that have receptorsfor a hormone and can respond to it.

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23
Q

Anatomy of Hypothalamus

A
  • shaped like a flattened funnel
  • forms floor and walls of third ventricle of the brain
  • regulates primitive functions of the body from water balance and thermoregulation to sex drive and childbirth
  • many of its functions carried out by pituitary gland
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24
Q

Pituitary Gland

A

(Hypophysis)
•suspended from hypothalamus by a stalk –infundibulum
•location and size
–housed in sella turcica of sphenoid bone
–size and shape of kidney bean

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25
Q

infundibulum

A

suspends pituitary gland from hypothalamus

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26
Q

Pituitary Gland composed of two structures

A

composed of two structures with independent origins and separate functions
–adenohypophysis (anterior pituitary)
–neurohypophysis(posterior pituitary)

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27
Q

adenohypophysis

A

(anterior pituitary)
constitutes anterior three-quarters of pituitary
–has two segments:
•anterior lobe (pars distalis)
•pars tuberalissmall mass of cells adhering to stalk
–linked to hypothalamus by hypophyseal portal system

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28
Q

hypophysealportal system

A
  • hypothalamic releasing and inhibiting hormones travel in hypophyseal portal system from hypothalamus to anterior pituitary
  • hormones secreted by anterior pituitary
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29
Q

neurohypophysis

A

constitutes the posterior one-quarter of the pituitary
–has 3 parts:
•median eminence, infundibulum, and the posterior lobe (pars nervosa)

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30
Q

neurohypophysis is

A

nerve tissue, not a true gland
•nerve cell bodies in hypothalamus pass down the stalk as hypothalamo-hypophysealtract and end in posterior lobe
•hypothalamic neurons secrete hormones that are stored in neurohypophysis until released into blood

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31
Q

eight hormones produced in hypothalamus

A

–six regulate the anterior pituitary
–two are released into capillaries in the posterior pituitary when hypothalamic neurons are stimulated (oxytocin and antidiuretic hormone)

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32
Q

six releasing and inhibiting hormones stimulate or inhibit the anterior pituitary

A

–TRH, CRH, GnRH, and GHRH are releasing hormones that affect anterior pituitary secretion of TSH, PRL, ACTH, FSH, LH, and GH
–PIH inhibits secretion of prolactin, and somatostatin inhibits secretion growth hormone & thyroid stimulating hormone by the anterior pituitary

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33
Q

Hypothalamic Hormones

two other hypothalamic hormones are

A

oxytocin (OT)and antidiuretic hormone (ADH)
–both stored and released by posterior pituitary
–right and left paraventricular nuclei produce oxytocin(OT)
–supraoptic nuclei produce antidiuretic hormone (ADH)
–posterior pituitary does not synthesize them

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34
Q

anterior lobe of the pituitary synthesizes and secretes six principal hormones

A 
•two gonadotropin hormones that target gonads
–FSH (follicle stimulating hormone)
–LH (luteinizing hormone)
•TSH (thyroid stimulating hormone)
•ACTH (adrenocorticotropic hormone)
•PRL (prolactin)
•GH (growth hormone)
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35
Q

FSH

A

FSH (follicle stimulating hormone)

•stimulates secretion of ovarian sex hormones, development of ovarian follicles, and sperm production

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36
Q

LH

A

(luteinizing hormone)

•stimulates ovulation, stimulates corpus luteum to secrete progesterone, stimulates testes to secrete testosterone

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37
Q

TSH

A

(thyroid stimulating hormone)

–stimulates secretion of thyroid hormone

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38
Q

ACTH

A

(adrenocorticotropic hormone)

–stimulates adrenal cortex to secrete glucocorticoids

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39
Q

PRL

A

(prolactin)

–after birth stimulates mammary glands to synthesize milk, enhances secretion of testosterone by testes

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40
Q

GH

A

(growth hormone)

–stimulates mitosis and cellular differentiation

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41
Q

Posterior Pituitary Hormones

A

produced in hypothalamus
–transported by hypothalamo-hypophyseal tract to posterior lobe
–releases hormones when hypothalamic neurons are stimulated
•ADH(antidiuretic hormone)
•OT(oxytocin)

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42
Q

ADH

A

(antidiuretic hormone)
–increases water retention thus reducing urine volume and prevents dehydration
–also called vasopressin because it can cause vasoconstriction

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43
Q

OT

A

(oxytocin)
–surge of hormone released during sexual arousal and orgasm
•stimulate uterine contractions and propulsion of semen
–promotes feelings of sexual satisfaction and emotional bonding between partners
–stimulates labor contractions during childbirth
–stimulates flow of milk during lactation
–promotes emotional bonding between lactating mother and infant

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44
Q

Control of Pituitary Secretion

A

rates of secretion are not constant

–regulated by hypothalamus, other brain centers, and feedback from target organs

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45
Q

anterior lobe control

A

releasing hormones and inhibiting hormones from hypothalamus

•in cold weather, pituitary stimulated by hypothalamus to release TSH, leads to generation of body heat

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46
Q

posterior lobe control

A

neuroendocrine reflexes

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47
Q

neuroendocrine reflex

A

hormone release in response to nervous system signals

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48
Q

negative feedback

A

increased target organ hormone levels inhibits release of hormones

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49
Q

positive feedback

A

stretching of uterus increases OT release, causes contractions, causing more stretching of uterus, etc. until delivery

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50
Q

Growth Hormone

A

GH has widespread effects on the body tissues
–especially cartilage, bone, muscle, and fat
•induces liver to produce growth stimulants

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51
Q

insulin-like growth factors (IGF-I) or somatomedins(IGF-II)

A
  • stimulate target cells in diverse tissues
  • IGF-I prolongs the action of GH
  • hormone half-life –the time required for 50% of the hormone to be cleared from the blood
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52
Q

insulin-like growth factors (IGF-I) or somatomedins(IGF-II)

causes

A

protein synthesis increases
lipid metabolism increased
carbohydrate metabolism
electrolyte balance

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53
Q

pineal gland

A

attached to roof of third ventricle beneath the posterior end of corpus callosum
•after age 7, it undergoes involution(shrinkage)

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54
Q

pineal gland

main function

A

may synchronize physiological function with 24-hour circadian rhythms of daylight and darkness
–synthesizes melatonin from serotonin during the night

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55
Q

seasonal affective disorder

A

(SAD) occurs in winter or northern climates
–symptoms -depression, sleepiness, irritability and carbohydrate craving
–2 to 3 hours of exposure to bright light each day reduces the melatonin levels and the symptoms (phototherapy)

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56
Q

Thymus

A

•thymus plays a role in three systems: endocrine, lymphatic, and immune
•bilobed gland in the mediastinum superior to the heart
–goes through involution after puberty
•site of maturation of T cells important in immune defense

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57
Q

Thymus secretes

A

secretes hormones (thymopoietin, thymosin, and thymulin) that stimulate development of other lymphatic organs and activity of T-lymphocytes

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58
Q

Thyroid Gland Anatomy

A

largest endocrine gland
–composed of two lobes and an isthmus below the larynx
–dark reddish brown color due to rich blood supply

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59
Q

thyroid follicles

A

sacs that compose most of thyroid
–contain protein rich colloid
–follicular cells –simple cuboidal epithelium that lines follicles

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60
Q

thyroid follicles secrete

A 
secretes thyroxine (T4 because of 4 iodine atoms) and triiodothyronine (T3) –T4 which is converted to T3
–increases metabolic rate, O2consumption, heat production (calorigenic effect), appetite, growth hormone secretion, alertness and quicker reflexes
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61
Q

parafollicular (C or clear) cellssecrete

A

calcitonin with rising blood calcium

–stimulates osteoblast activity and bone formation

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62
Q

thyroid follicles are filled with

A

colloid and lined with simple cuboidal epithelial cells (follicular cells).

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63
Q

Parathyroid Glands

A

usually four glands partially embedded in posterior surface of thyroid gland
–can be found from as high as hyoid bone to as low as aortic arch

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64
Q

Parathyroid Glands secrete

A 
secrete parathyroid hormone (PTH)
–increases blood Ca2+ levels
•promotes synthesis of calcitriol
•increases absorption of Ca2+
•decreases urinary excretion
•increases bone resorption
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65
Q

Adrenal Gland

A

small gland that sits on top of each kidney
•they are retroperitoneal like the kidney
•adrenal cortex and medulla formed by merger of two fetal glands with different origins and functions

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66
Q

adrenal medulla

A

inner core, 10% to 20% of gland

•has dual nature acting as an endocrine gland and sympathetic ganglion of sympathetic nervous system

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67
Q

adrenal medulla innervated by

A

innervated by sympathetic preganglionic fibers

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68
Q

when stimulated release

A

catecholamines(epinephrineand norepinephrine) and a trace of dopamine directly into the bloodstream

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69
Q

catecholamines

A

effect is longer lasting than neurotransmitters
–increases alertness and prepares body for physical activity –
•mobilize high energy fuels, lactate, fatty acids, and glucose
•glycogenolysisand gluconeogenesisboost glucose levels
•glucose-sparing effect because inhibits insulin secretion
–muscles use fatty acids saving glucose for brain
–increasesblood pressure, heart rate, blood flow to muscles, pulmonary air flow and metabolic rate
–decreasesdigestion and urine production

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70
Q

Adrenal Cortex

A

surrounds adrenal medulla and produces more than 25 steroid hormones called corticosteroidsor corticoids

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71
Q

Adrenal Cortex

three layers of glandular tissue

A

zona glomerulosa
zona fasciculate
zona reticularis

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72
Q

zona glomerulosa

A

(thin, outer layer)
•cells are arranged in rounded clusters
•secretes mineralocorticoid–regulate the body’s electrolyte balance

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73
Q

zona fasciculata

A

(thick, middle layer)
•cells arranged in fascicles separated by capillaries
•secretes glucocorticoids

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74
Q

zona reticularis

A

(narrow, inner layer)
•cells in branching network
•secretes sex steroids

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75
Q

mineralocorticoids

A

zona glomerulosa
–regulate electrolyte balance
–aldosterone stimulates Na+retention and K+excretion, water is retained with sodium by osmosis, so blood volume and blood pressure are maintained

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76
Q

glucocorticoids

A

–regulate metabolism of glucose and other fuels
–especially cortisol, stimulates fat and protein catabolism, gluconeogenesis(glucose from amino acids and fatty acids) and release of fatty acids and glucose into blood
–helps body adapt to stress and repair tissues
–anti-inflammatory effect becomes immune suppression with long-term use

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77
Q

sex steroids

A

zona reticularis
–androgens –sets libido throughout life; large role in prenatal male development (includes DHEA which other tissues convert to testosterone)
–estradiol–small quantity, but important after menopause for sustaining adult bone mass; fat converts androgens into estrogen

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78
Q

Adrenal Gland Interactions

A

medulla and cortex of adrenal gland are not functionally independent
•medulla atrophies without the stimulation of cortisol
•some chromaffin cells of medullary origin extend into the cortex
–they stimulate the cortex to secrete corticosteroids when stress activates the sympathetic nervous system

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79
Q

Pancreas

A

exocrine digestive gland and endocrine cell clusters (pancreatic islets) found retroperitoneal, inferior and posterior to stomach

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80
Q

pancreatic islets

A

1-2 million pancreatic islets (Islets of Langerhans) produce hormones
–other 98% of pancreas cells produces digestive enzymes

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81
Q

insulin secreted by

A

B or beta () cells
–secreted during and after meal when glucose and amino acid blood levels are rising
–stimulates cells to absorb these nutrients and store or metabolize them lowering blood glucose levels

82
Q

diabetes mellitus

A

insufficiency or inaction is cause of diabetes mellitus

83
Q

Pancreatic Hormones

A

glucagon
somatostatin
pancreatic polypeptide
gastrin

84
Q

glucagon

A

secreted by A or alpha () cells
–released between meals when blood glucose concentration is falling
–in liver, stimulates gluconeogenesis, glycogenolysis, and the release of glucose into the circulation raising blood glucose level
–in adipose tissue, stimulates fat catabolism and release of free fatty acids
–glucagon also released to rising amino acid levels in blood, promotes amino acid absorption, and provides cells with raw material for gluconeogenesis

85
Q

somatostatin

A

secreted by D or delta () cells
–partially suppresses secretion of glucagon and insulin
–inhibits nutrient digestion and absorption

86
Q

pancreatic polypeptide

A

secreted by PP cells or F cells)

–inhibits gallbladder contraction and secretion pancreatic digestive enzymes

87
Q

gastrin

A

secreted by G cells

–stimulates stomach acid secretion, motility and emptying

88
Q

hyperglycemic hormones

A

raise blood glucose concentration

–glucagon, growth hormone, epinephrine, norepinephrine, cortisol, and corticosterone

89
Q

hypoglycemic hormones

A

blood glucose

–insulin

90
Q

The Gonads

A

ovaries and testes are both endocrine and exocrine

91
Q

exocrine product

A

whole cells -eggs and sperm (cytogenic glands)

92
Q

endocrine product

A

gonadal hormones –mostly steroids

93
Q

ovarian hormones

A

–estradiol, progesterone, and inhibin

94
Q

testicular hormones

A

testosterone, weaker androgens, estrogen and inhibin

95
Q

functions of estradiol and progesterone

A

–development of female reproductive system and physique including adolescent bone growth
–regulate menstrual cycle, sustain pregnancy
–prepare mammary glands for lactation

96
Q

inhibin suppresses

A

inhibin suppresses FSH secretion from anterior pituitary

97
Q

testicular hormones

A

testosterone and other steroids from interstitial cells (cells of Leydig) nestled between the tubules
–inhibinfrom

98
Q

testosterone

A

testosterone and other steroids from interstitial cells (cells of Leydig) nestled between the tubules
•stimulates development of male reproductive system in fetus and adolescent, and sex drive
•sustains sperm production

99
Q

inhibin

A

inhibin from sustentacular (Sertoli) cells

•limits FSH secretion in order to regulate sperm production

100
Q

skin

A

keratinocytes convert a cholesterol-like steroid into cholecalciferol using UV from sun –Vitamin D is a steroid hormone

101
Q

liver

A

involved in the production of at least five hormones
–converts cholecalciferol into calcidiol
–secretes angiotensinogen(a prohormone)
•precursor of angiotensin II (a regulator of blood pressure)
–secretes 15% oferythropoietin (stimulates bone marrow)
–hepcidin –promotes intestinal absorption of iron
–source of IGF-I that controls action of growth hormone

102
Q

kidneys

A

plays role in production of three hormones
–converts calcidiol to calcitriol, the active form of vitamin D
•increases Ca2+ absorption by intestine and inhibits loss in the urine
–secrete renin that converts angiotensinogen to angiotensin I
•angiotensin II created by converting enzyme in lungs
–constricts blood vessels and raises blood pressure
–produces 85% of erythropoietin–
•stimulates bone marrow to produce RBCs

103
Q

heart

A

–cardiac muscle secretes atrial and brain natriuretic peptides (ANP and BNP) in response to an increase in blood pressure

104
Q

stomach and small intestine

A

secrete at least ten enteric hormones secreted by enteroendocrine cells

105
Q

adipose tissue

A

secretes leptin

–slows appetite

106
Q

osseous tissue

A

osteocalcinsecreted by osteoblasts
–increases number of pancreatic beta cells, pancreatic output of insulin, and insulin sensitivity of other body tissues
–inhibits weight gain and onset of type II diabetes mellitus

107
Q

placenta

A

secretes estrogen, progesterone and others

108
Q

Hormone Chemistry

A 
three chemical classes
–steroids
-peptides and glycoproteins
–monoamines (biogenic amines)
•all hormones are made from either cholesterol or amino acids with carbohydrate added to make glycoproteins
109
Q

steroids

A
  • derived from cholesterol
  • secreted by gonads and adrenal glands
  • estrogens, progesterone, testosterone, cortisol, corticosterone, aldosterone, DHEA, and calcitriol (vitamin D)
110
Q

peptides and glycoproteins

A
  • created from chains of amino acids
  • secreted by pituitary and hypothalamus
  • oxytocin, antidiuretic hormone, releasing and inhibiting hormones, and anterior pituitary hormones
111
Q

–monoamines (biogenic amines)

A
  • derived from amino acids
  • secreted by adrenal, pineal, and thyroid glands
  • epinephrine, norepinephrine, melatonin, and thyroid hormone
112
Q

Hormone Synthesis: Steroid Hormones

A

synthesized from cholesterol –differs in functional groups attached to 4-ringed steroid backbone

113
Q

Peptides

A
  • synthesized in same way as any protein
  • at first is an inactive preprohormone
  • first several amino acids is a signal peptide that guides it into cisterna of rough endoplasmic reticulum
  • signal peptide removed to form prohormone
  • Golgi does final transformation to hormonepackaged for secretion
114
Q

Hormone Synthesis: Insulin

A

begins as preproinsulin, then becomes proinsulin

•when connecting peptideis removed, two polypeptide chains are formed that make up insulin

115
Q

Monoamines

A

melatonin is synthesized from amino acid tryptophan, and other monoamines from amino acid tyrosine
–thyroid hormone is composed of 2 tyrosines

116
Q

T3 and T4 Synthesis

A

follicular cells

TSH

117
Q

follicular cells

A

–absorb iodide(I-)ions from blood and store in lumen as a reactive form of iodine
–synthesize thyroglobulin and store in lumen
•forms colloid
•contains lots of tyrosine
–tyrosine and iodine combine to form thyroxine (T4) bound to thyroglobulin
–stored in follicle

118
Q

TSH

A

–stimulates follicular cells to remove T4from thyroglobulin for release into plasma
–most T3is produced in liver or by target cells removing an iodine from circulating T4
–95% T4and 5% T3

119
Q

Chemistry of Thyroid Hormone

A

MIT contains one iodine atom, DIT has twoT3-combination of MIT plus DITT4 -combination of two DITs

120
Q

Hormone Transport

monoamines and peptides

A

most monoamines and peptides are hydrophilic

–mix easily with blood plasma

121
Q

Hormone Transport

steroids and thyroid hormone

A

steroids and thyroid hormone are hydrophobic
–bind to transport proteins (albumins and globulins synthesized by the liver)
–bound hormones have longer half-life
•protected from liver enzymes and kidney filtration
–only unbound hormone leaves capillaries to reach target cell

122
Q

Hormone Transport

thyroid hormone

A

thyroid hormone binds to three transport proteins in the plasma
–albumin, thyretin and TBG (thyroxine-binding globulin)
–more than 99% of circulating TH is protein bound

123
Q

Hormone Transport

steroid hormones

A

bind to globulins

–transcortin –the transport protein for cortisol

124
Q

Hormone Transport

aldosterone

A

short half-life; 85% unbound, 15% binds weakly to albumin and others

125
Q

Hormone Receptors

A

hormones stimulate only those cells that have receptors for them

126
Q

Hormone Receptors

A

receptors are protein or glycoprotein molecules:
–on plasma membrane, in the cytoplasm, or in the nucleus
•receptors act like switches turning on metabolic pathways when hormone binds to them
•usually each target cell has a few thousand receptors for a given hormone

127
Q

receptor-hormone interactions exhibit

A

specificity and saturation

128
Q

specificity

A

specific receptor for each hormone

129
Q

saturation

A

saturated when all receptor molecules are occupied by hormone molecules

130
Q

Hormone Mode of Action

hydrophobic hormones

A

–penetrate plasma membrane and enter nucleus
–act directly on the genes changing target cell physiology
–estrogen, progesterone, thyroid hormone act on nuclear receptors
–take several hours to days to show effect due to lag for protein synthesis

131
Q

Hormone Mode of Action

hydrophilic hormones

A

–cannot penetrate into target cell

–must stimulate physiology indirectly

132
Q

Thyroid Hormone

A

thyroid hormone enters target cell by diffusion –mostly as T4with little metabolic effect
•within target cell, T4is converted to more potent T3
•T3enters target cells and binds to receptors in chromatin
•activates genes

133
Q

Peptides and Catecholamines: Hydrophilic

A 
hormone binds to cell-surface receptor
•receptor linked to second messenger system on other side of the membrane
•activates G protein which
•activates adenylate cyclase
•produces cAMP
•activates or inhibits enzymes
•metabolic reactions:
–synthesis
–secretion
–change membrane potentials
134
Q

Other Second Messengers

A
  • diacylglycerol (diglyceride) second-messenger system
  • inositol triphosphate second-messenger system
  • act on cell metabolism in a variety of ways
135
Q

Enzyme Amplification

A
  • hormones are extraordinarily potent chemicals
  • one hormone molecule can trigger the synthesis of many enzyme molecules.
  • very small stimulus can produce very large effect
  • circulating concentrations very low
136
Q

Modulation of Target Cell Sensitivity

A

target cell sensitivity adjusted by changing the number of receptors

137
Q

up-regulation

A

regulation means number of receptors is increased

–sensitivity is increased

138
Q

down-regulation

A 
regulation reduces number of receptors
–cell less sensitive to hormone
–happens with long-term exposure to high hormone concentrations
•bind to other receptors
•converted to different hormone
139
Q

Hormone Interactions

A

most cells sensitive to more than one hormone and exhibit interactive effects

140
Q

synergistic effects

A

–multiple hormones act together for greater effect

•synergism between FSH and testosterone on sperm production

141
Q

permissive effects

A

–one hormone enhances the target organ’s response to a second later hormone
•estrogen prepares uterus for action of progesterone

142
Q

antagonistic effects

A

–one hormone opposes the action of another

•insulin lowers blood glucose and glucagon raises it

143
Q

Hormone Clearance

A

•hormone signals must be turned off when they have served their purpose
•most hormones are taken up and degraded by liver and kidney
–excreted in bile or urine

144
Q

metabolic clearance rate

A

(MCR)
–rate of hormone removal from the blood
–half-life-time required to clear 50% of hormone from the blood
–faster the MCF, the shorter is the half-life

145
Q

stress

A

caused by any situation that upsets homeostasis and threatens one’s physical or emotional well-being
•injury, surgery, infection, intense exercise, pain, grief, depression, anger, etc

146
Q

general adaptation syndrome

A

(GAS)
–the consistent way body reacts to stress –typically involves elevated levels of epinephrine and glucocorticoids (especially cortisol)

147
Q

general adaptation syndrome

occurs in three stages:

A
  1. alarm reaction
  2. stage of resistance
  3. stage of exhaustion
148
Q

Alarm Reaction

A

•initial response
•mediated by norepinephrine from the sympathetic nervous system and epinephrine from the adrenal medulla
–prepare body to fight or flight
–stored glycogen is consumed
–increase in aldosterone and angiotensin levels
•angiotensin helps raise blood pressure
•aldosterone promotes sodium and water conservation

149
Q

Stage of Resistance

A

after a few hours, glycogen reserves gone, but brain still needs glucose
•provide alternate fuels for metabolism
•stage dominated by cortisol
•hypothalamus secretes corticotropin-releasing hormone
•pituitary secretes an increase in ACTH

150
Q

pituitary secretes an increase in ACTH

A

–stimulates the adrenal cortex to secrete cortisol and other glucocorticoids
–promotes the breakdown of fat and protein into glycerol, fatty acids, and amino acids –for gluconeogenesis

151
Q

glucose-sparing effect

A

cortisol has glucose-sparing effect –inhibits protein synthesis leaving free amino acids for gluconeogenesis
–adverse effects of excessive cortisol
–depresses immune function
–Increases susceptibility to infection and ulcers
–lymphoid tissues atrophy, antibody levels drop, and wounds heal poorly

152
Q

Stage of Exhaustion

A

•when stress continues several months, and fat reserves are gone, homeostasis is overwhelmed
–marked by rapid decline and death
•protein breakdown and muscle wasting
•loss of glucose homeostasis because adrenal cortex stops producing glucocorticoids
•aldosterone promotes water retention and hypertension
–conserves sodium and hastens elimination of K+and H+
–hypokalemia and alkalosis leads to death
•death results from heart and kidney failure or overwhelming infection

153
Q

paracrines

A

chemical messengers that diffuse short distances and stimulate nearby cells
–unlike neurotransmitters not produced in neurons
–unlike hormones not transported in blood

154
Q

•a single chemical can act as

A

a hormone, paracrine, or even neurotransmitter in different locations

155
Q

–histamine

A
  • from mast cells in connective tissue

* causes relaxation of blood vessel smooth muscle

156
Q

nitric oxide

A

•from endothelium of blood vessels, causes vasodilation

157
Q

somatostatin

A

•from gamma cells, inhibits secretion of alpha and beta cells

158
Q

catecholamines

A

•diffuse from adrenal medulla to cortex

159
Q

Eicosanoids

A

important family of paracrines

–derived from fatty acid called arachidonic acid

160
Q

lipoxygenase

A

converts arachidonic acid into leukotrienes

161
Q

leukotrienes

A

mediates allergic and inflammatory reactions

162
Q

cyclooxygenase

A

converts arachidonic acid to three other types of eicosanoids

163
Q

prostacyclin

A

•inhibits blood clotting and vasoconstriction

164
Q

thromboxanes

A
  • produced by blood platelets after injury
  • overrides prostacyclin
  • stimulates vasoconstriction and clotting
165
Q

prostaglandinsincludes

A
  • PGE: relaxes smooth muscle in bladder, intestines, bronchioles, uterus and stimulates contraction of blood vessels
  • PGF: opposite effects
166
Q

Anti-inflammatory Drugs

A
  • cortisol and corticosterone

* aspirin, ibuprofen, & celecoxib (Celebrex)

167
Q

•cortisol and corticosterone

A

–steroidal anti-inflammatory drugs (SAIDs)
–inhibit inflammation by blocking release of arachidonic acid from plasma membrane and inhibit synthesis of eicosanoids
•disadvantage –produce symptoms of Cushing syndrome

168
Q

aspirin, ibuprofen, & celecoxib (Celebrex)

A

–nonsteroidal anti-inflammatory drugs (NSAIDs)
•COX inhibitors since block cyclooxygenase (COX)
•do not affect lipoxygenase function or leukotriene production
•useful in treatment of fever and thrombosis
–inhibit prostaglandin and thromboxane synthesis

169
Q

Endocrine Disorders

A

variations in hormone concentration and target cell sensitivity have noticeable effects on body

170
Q

hyposecretion

A

inadequate hormone release

–tumor or lesion destroys gland or interferes with its ability to receive signals from another gland

171
Q

hypersecretion

A

excessive hormone release

–tumors or autoimmune disorder

172
Q

pheochromocytoma

A

tumor of adrenal medulla secretes excessive epinephrine and norepinephrine

173
Q

toxic goiter

A

(graves disease) –autoantibodies mimic effect of TSH on the thyroid causing thyroid hypersecretion

174
Q

Pituitary Disorders

A

hypersecretion of growth hormone (GH)

175
Q

acromegaly

A

thickening of bones and soft tissues in adults
•especially hands, feet and face
–problems in childhood or adolescence

176
Q

gigantism

A

gigantism if hypersecretion

177
Q

dwarfism

A

pituitary dwarfism if hyposecretion –rare since growth hormone is now made by genetically engineered bacteria

178
Q

Thyroid Gland Disorders

A

congenital hypothyroidism
myxedema
goiter

179
Q

congenital hypothyroidism

A

(decreased TH)
–hyposecretion present a birth (formerly cretinism)
–treat with oral thyroid hormone

180
Q

myxedema

A

(decreased TH)
–adult hypothyroidism
–treat with oral thyroid hormone

181
Q

goiter

A

any pathological enlargement of the thyroid gland

182
Q

endemic goiter

A

•dietary iodine deficiency, no TH, no feedback, increased TSH stimulates hypertrophy

183
Q

toxic goiter

A

(Graves disease)
•autoantibodies mimic the effect of TSH on the thyroid causing hypersecretion
•overgrown thyroid produces functional TH

184
Q

Parathyroid Disorders

A

hypoparathyroidism

185
Q

hypoparathyroidism

A
  • surgical excision during thyroid surgery

* fatal tetany in 3 -4 days due to rapid decline in blood calcium level

186
Q

hyperparathyroidism

A

excess PTH secretion
•parathyroid tumor
•bones become soft, fragile, and deformed
•Ca2+ and phosphate blood levels increase
•promotes renal calculi formation

187
Q

Adrenal Disorders

A 
Cushing syndrome
adrenogenital syndrome (AGS)
188
Q

Cushing syndrome

A

excess cortisol secretion
–hyperglycemia, hypertension, weakness, edema
–rapid muscle and bone loss due to protein catabolism
–abnormal fat deposition
•moon face and buffalo hump

188
Q

Diabetes Mellitus

A

most prevalent metabolic disease in world

–disruption of metabolism due to hyposecretion or inaction of insulin

189
Q

Diabetes Mellitus

symptoms

A
  • polyuria(excess urine output), polydipsia(intense thirst) and polyphagia(hunger)
  • revealed by elevated blood glucose, glucose in urine and ketones in the urine
190
Q

polyuria

A

excess urine output

191
Q

polydipsia

A

intense thirst

192
Q

polyphagia

A

hunger

193
Q

transport maximum

A

limit to how fast the glucose transporters can work to reabsorb
–excess glucose enters urine and water follows it
•causes polyuria, dehydration, and thirst

194
Q

Types of Diabetes Mellitus

A

Type 1

Type 2

195
Q

Type 1

A

(IDDM) –5 to 10% of cases in US
–insulin is always used to treat Type 1
•insulin injections, insulin pump, or dry insulin inhaler
•monitoring blood glucose levels and controlled diet
–hereditary susceptibility if infected with certain viruses (rubella, cytomegalovirus)
–autoantibodies attack and destroy pancreatic beta cells

196
Q

Type 2

A

(NIDDM) –90 to 95% of diabetics
–problem is insulin resistance
•failure of target cells to respond to insulin
–risk factors are heredity, age (40+),obesity, and ethnicity –Native American, Hispanic, and Asian
–treated with weight loss program and exercise since:
•loss of muscle mass causes difficulty with regulation of glycemia
•adipose signals interfere with glucose uptake into most cells
–oral medications improve insulin secretion or target cell sensitivity

197
Q

pathogenesis

A

cells cannot absorb glucose, must rely on fat and proteins for energy needs -weight loss and weakness
–fat catabolism increases free fatty acids and ketones in blood

198
Q

ketonuria

A

ketonuria promotes osmotic diuresis, loss of Na+ and K+, irregular heartbeat, and neurological issues

199
Q

ketoacidosis

A

ketoacidosis occurs as ketones decrease blood pH

–deep, gasping breathing and diabetic coma are terminal result

200
Q

chronic pathology (chronic hyperglycemia)

A

leads to neuropathy and cardiovascular damage from atherosclerosis and microvascular disease
•arterial damage in retina and kidneys (common in type I), atherosclerosis leads to heart failure (common in type II)

201
Q

diabetic neuropathy

A

nerve damage from impoverished blood flow can lead to erectile dysfunction, incontinence, poor wound healing, and loss of sensation from area

2 - Keiser A&P 2 (15 decks)

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