Title: The Endocrine System
1The Endocrine System
- Endocrine and nervous systems work together
- Endocrine system
- hormones released into the bloodstream travel
throughout the body - target is usually far from site of synthesis
- binds to receptors on or in target
- targets cells throughout the body
- results may take hours, but last longer
- Nervous system
- certain parts release hormones into blood
- rest releases neurotransmitters that excite or
inhibit nerve, muscle gland cells - results in milliseconds, brief duration of
effects
2General Functions of Hormones
- Help regulate
- extracellular fluid
- metabolism
- biological clock
- contraction of cardiac smooth muscle
- glandular secretion
- some immune functions
- Growth development
- Reproduction
3Endocrine Glands Defined
- Exocrine glands
- secrete products into ducts which empty into body
cavities or body surface - sweat, oil, mucous, digestive glands
- Endocrine glands
- secrete products (hormones) into bloodstream
- pituitary, thyroid, parathyroid, adrenal, pineal
- other organs secrete hormones as a 2nd function
- hypothalamus, thymus, pancreas,ovaries,testes,
kidneys, stomach, liver, small intestine, skin,
heart placenta
4Extracellular Signaling Mechanisms
- most signals produced by cells within the body
bind to receptors that are specific for that
signal - most receptors are found on the cell surface
- although some can be found within the cell!
- binding of the signal (ligand) to the receptor
results in a series of events (signal
transduction) within the cell that changes the
cells function - e.g. may change the transcription rate of a gene
effects protein production
5Hormones Mechanisms of Signaling
- hormone producing cell endocrine cell
- e.g. thyroid, pituitary
- Autocrine signaling
- cell responds to the hormone it produces
- Paracrine signaling
- local action
- local hormone (paracrine hormones)
- act on neighboring cells
- autocrines act on same cell that secreted them
- Endocrine signaling
- circulating hormones (endocrine hormones)
- act on distant targets
- travel in blood
6Types of Hormones
- water-soluble
- lipid -soluble
7Lipid-soluble Hormones
- Steroids
- lipids derived from cholesterol
- made in SER
- different functional groups attached to core of
structure provide uniqueness - e.g. cortisol, progesterone, estrogen,
testosterone, aldosterone - Thyroid hormones
- tyrosine ring plus attached iodines
- are lipid-soluble
- Retinoic acid
- lipids derived from retinol (vitamin A)
- regulate proliferation, differentiation and death
of many cell types - some vitamins can acts a lipid-soluble hormones
- e.g. vitamin D
- Nitric oxide (NO)
- - gas
testosterone
aldosterone
cortisol
8Lipid-soluble Hormones
- Eicosanoids
- prostaglandins or leukotrienes
- derived from arachidonic acid (fatty acid)
- AA is converted either into prostaglandin H or
into the leukotrienes - conversion of AA into prostaglandins is regulated
by the COX enzymes - both act in the inflammatory reaction
- e.g. stimulate smooth muscle cells to contract
- e.g. stimulate nerve cells pain
9Water-soluble Hormones
- Amine, peptide and protein hormones
- modified amino acids to protein chains
- serotonin, melatonin, histamine, epinephrine,
insulin, dopamine - protein hormones comprised of one or many
polypeptide chains - insulin, glucagon
- peptide hormones comprised of chains of amino
acids - e.g. growth hormone, oxytocin
- amine hormones derived from the amino acids
tyrosine or tryptophan - epinephrine (tyrosine and phenylalanine),
serotonin (tryptophan), dopamine (tyrosine) - can also act as neurotransmitters
insulin
10Action of Lipid-Soluble Hormones Endogenous
signaling
- Hormone must be carried by a transport protein
that allows it to dissolve within the aqueous
(watery) environment of the blood plasma - Hormone diffuses through phospholipid bilayer
into cell - the receptor is located within the cell
(cytoplasm or the nucleus) - binding of H to R results in its translocation
into the nucleus - the H then binds directly to specific sequences
within the DNA response elements - this binding turns on/off specific genes
activates or inhibits gene transcription - if turned on - new mRNA is formed directs
synthesis of new proteins - new protein alters cells activity
- if turned off no new protein results and the
cells activity is altered
11Action of Lipid-Soluble Hormones
- some lipid-soluble hormone dont cross the plasma
membrane too large - therefore they bind with receptors on the cell
surface and trigger signaling events within the
cells - signal similar to water-soluble hormones
- e.g. prostaglandins
12Action of Water-Soluble Hormones
- easily travels through the blood - hydrophilic
- but cannot diffuse through plasma membrane!
- therefore absolutely requires the expression of
receptors on the cell surface integral membrane
proteins that act as first messenger - the receptor protein activates a series of
signaling events within the cells - e.g. epinephrine binds to receptor and activates
an adjacent G-protein in membrane - G-protein activates adenylate cyclase to convert
ATP to cyclic AMP (cAMP) in the cytosol - cAMP is the 2nd messenger
- cAMP activates a series of proteins in the
cytosol called kinases - kinases act to phosphorylate their targets
either activating them or inhibiting them - this speeds up/slows down physiological responses
within the cell - phosphodiesterase inactivates cAMP quickly
- many second messengers are made in cells in
response to specific hormones - e.g. calcium, IP3, DAG
- Cell response is turned off unless new hormone
molecules arrive - this mechanism allows for amplification one H-R
combination can activate two G proteins which
activates 4 kinases which activate 16 more
kinases etc.
13Hormonal Interactions
- Permissive effect
- Second hormone permits the action of the first
- estrogen LH are both needed for oocyte
production - Synergistic effect
- two hormones act together for greater effect (vs.
individually) - thyroid strengthens epinephrines effect upon
lipolysis - Antagonistic effects
- two hormones with opposite effects
- insulin promotes glycogen formation glucagon
stimulates glycogen breakdown
14Control of Hormone Secretion
- Regulated by signals from nervous system,
chemical changes in the blood or by other
hormones - Negative feedback control (most common)
- decrease/increase in blood level is reversed
- Positive feedback control
- the change produced by the hormone causes more
hormone to be released - Disorders involve either hyposecretion or
hypersecretion of a hormone
15Hypothalamus and Pituitary Gland
- Both are master endocrine glands since their
hormones control other endocrine glands - Hypothalamus is a section of brain above where
pituitary gland is suspended from stalk - Hypothalamus receives input from cortex,
thalamus, limbic system internal organs - Hypothalamus controls pituitary gland with 7
different releasing inhibiting hormones PLUS
two additional hormones (ADH oxytocin)
16- hypothalamus
- -Emotions, autonomic functions, hormone
production - -mamillary bodies serve as relay stations for
reflexes related to smell - -supraoptic and preoptic regions that function in
vision - -major functions
- 1. control of the ANS integrates signals from
the ANS (regulated smooth and cardiac muscle
contraction) - major regulator of visceral activities (heart
rate, food movements, contraction of bladder) - 2. produces hormones connects with pituitary to
regulate its activity
3. regulates emotional and behavioral patterns
rage, aggression, pain and pleasure sexual
arousal 4. regulates eating drinking
hypothalamus contains a thirst center which
responds to a rise in osmotic pressure in the
ECF (dehydration) 5. controls body temperature
monitors temp of blood flowing through the
hypothalamus
17Pituitary Gland
- cells secrete 9 different hormones
- regulates the activity of the pituitary through
its secretion of 7 specific releasing and
inhibiting hormones - e.g. pituitary hormone somatotropin
- hypothalmic hormones somatotropin releasing
hormone (SRH) and somatotropin inhibiting hormone
(SIH) - also secretes two specific hormones that are
stored in the pituitary oxytocin and
anti-diuretic hormone (ADH) - portion that marks the connection with the
pituitary median eminence - near the ME is a group of cells neurosecretory
cells - secrete the hypothalmic releasing and inhibiting
hormones that regulate the pituitary - stored in synaptic vesicles
- released upon production of an action potential
via exocytosis into the blood stream - Diffusion down to the anterior pituitary
18Pituitary Gland
-hypothalamic hormones (releasing hormones) reach
the pituitary via a portal system of capillaries
hypophyseal portal system (HPS) -flow of blood
from the hypothal. into portal veins that carry
blood to the capillaries of the ant
pituitary -superior hypophyseal arteries
are branches off of the internal carotid- -bring
blood into the hypothal. -where the hypothal. and
infundibulum meet they divide into the
primary plexus of the HPS -from this plexus blood
drains into hypophyseal portal veins -at the
anterior pituitary these portal veins divide into
the secondary plexus of the HPS -release of the
hypothalmic releasing inhibiting hormones into
the primary plexus of the HPS and travel to the
secondary plexus
- Pea-shaped, 1/2 inch gland found in sella turcica
of sphenoid - Infundibulum attaches it to brain
- Anterior lobe 75 develops from roof of mouth
- Posterior lobe 25
- ends of axons of 10,000 neurons found in
hypothalamus - neuroglial cells called pituicytes
19Anterior Pituitary Gland
Hormones human growth hormone- hGH thyroid
stimulating - TSH follicle stimulating-
FSH leutinizing hormone - LH prolactin adrenocorti
cotropin - ACTH melanocyte stimulating - MSH
- 5 types of cells
- somatotrophs secrete hGH/somatotropin
- thyrotrophs secrete TSH/thyrotropin
- gonadotrophs secrete FSH, LH
- lactotrophs secrete prolactin
- corticotrophs secrete ACTH/corticotropin MSH
20Anterior Pituitary Gland Control of Secretion
- first level of regulation releasing and
inhibiting hormones of the hypothalamus - second level is negative feedback by hormones
release by the target gland - e.g. corticotropin (ACTH) release stimulated by
CRH/corticotropin releasing hormone - travels to anterior pituitary and stimulates
release of ACTH - ACTH travels to the adrenal gland stimulates
production and secretion of cortisol - increase of cortisol beyond the normal range
triggers release of CIH/corticotropin inhibiting
hormone - CIH shuts down the secretion of ACTh by the
anterior pituitary
21Human Growth Hormone
- Produced by somatotrophs
- release is stimulated by GHRH from the
hypothalamus - promotes synthesis of insulin-like growth factors
- IGFs are made primarily by the liver
- common target cells for IGFs skeletal muscle,
cartilage and bone cells - increases cell growth cell division by
increasing their uptake of amino acids
synthesis of proteins - hGH also
- stimulates lipolysis in adipose - so fatty acids
can be used for ATP - stimulates synthesis and release of glucose into
the blood by the liver gluconeogenesis - retards use of glucose for ATP production so
blood glucose levels remain high enough to supply
brain - hGH secretion is promoted by decreased fatty
acids and amino acids in the blood, decreased
blood sugar, deep sleep, increased activity by
the sympathetic NS, hormones (glucagon, estrogen,
cortisol and insulin)
- Excess of growth hormone
- raises blood glucose concentration
- pancreas releases insulin continually
- beta-cell burnout
- Diabetogenic effect eventually causes diabetes
mellitis if no insulin activity occurs
22Regulation of hGH
- Low blood sugar stimulates release of GHRH from
hypothalamus - anterior pituitary releases more hGH, more
glycogen broken down into glucose by liver cells - High blood sugar stimulates release of GHIH from
hypothalamus - less hGH from anterior pituitary, glycogen does
not breakdown into glucose
23Medical application
- Hyposecretion during childhood pituitary
dwarfism (proportional, childlike body) - Hypersecretion during childhood giantism
- very tall, normal proportions
- Hypersecretion as adult acromegaly
- growth of hands, feet, facial features
thickening of skin
24Thyroid Stimulating Hormone (TSH)
- Hypothalamus regulates thyrotroph cells
- Thyrotroph cells produce TSH
- TSH stimulates the synthesis secretion of T3
and T4 - Metabolic rate stimulated
25Follicle Stimulating Hormone (FSH)
- Releasing hormone from
hypothalamus controls
gonadotrophs - Gonadotrophs release
follicle stimulating hormone - FSH functions
- initiates the formation of follicles within the
ovary - stimulates follicle cells to secrete estrogen
- stimulates sperm production in testes
26Luteinizing Hormone (LH)
- Releasing hormones from hypothalamus stimulate
gonadotrophs - Gonadotrophs produce LH
- In females, LH stimulates
- secretion of estrogen
- ovulation of 2nd oocyte from ovary
- formation of corpus luteum
- secretion of progesterone
- In males, stimulates interstitial cells
to secrete testosterone
27Prolactin (PRL)
- Hypothalamus regulates lactotroph cells
- Lactotrophs produce prolactin (also produced by
breast tissue) - during pregnancy high levels of estrogen
contribute - Under right conditions, prolactin increases
mammary gland size and causes milk production - during pregnancy high levels of progesterone
prevent milk let-down - also contributes to female orgasm, proliferation
of oligodendrocytes (!) - hypothalamus normally inhibits prolactin
production when not pregnant - arcuate nucleus produces dopamine which inhibits
lactotroph activity - Suckling reduces levels of hypothalamic
inhibition and prolactin levels rise along with
milk production - milk let-down also requires action of oxytocin
(promoted also by suckling) - also provides feelings of sexual gratification
after intercourse - counteracts dopamine (sexual arousal) produces
a sexual refractory period
28Adrenocorticotrophic Hormone
- Hypothalamus releasing hormones stimulate
corticotrophs - Corticotrophs secrete ACTH MSH
- ACTH stimulates cells of the adrenal cortex that
produce glucocorticoids
29Melanocyte-Stimulating Hormone
- Secreted by corticotroph cells under the control
of MRH (MSH-releasing hormone) - Releasing hormone from hypothalamus increases its
release from the anterior pituitary - Function not certain in humans (increase skin
pigmentation in frogs )
30Posterior Pituitary Gland (Neurohypophysis)
- Does not synthesize hormones
- Consists of axon terminals of hypothalamic
neurons - Neurons release two neurotransmitters that enter
capillaries - antidiuretic hormone
- oxytocin
31Oxytocin
- Two target tissues both involved in
neuroendocrine reflexes - During delivery
- babys head stretches cervix
- hormone release enhances uterine muscle
contraction - baby placenta are delivered
- After delivery
- suckling hearing babys cry stimulates milk
ejection - hormone causes muscle contraction milk ejection
32Antidiuretic Hormone (ADH)
- Known as vasopressin
- Functions
- decrease urine production
- decrease sweating
- increase BP
- Dehydration
- ADH released
- Overhydration
- ADH inhibited
33The peripheral endocrine glands
- thyroid and parathyroid
- adrenal glands
- ovaries and testes
- pancreas
34Thyroid Gland
- comprised of microscopic sacs called follicles
follicular cells making up the walls, surrounds a
lumen - synthesize T3 T4 (thyroxin)
- In between follicular cells cells are
parafollicular cells - produce calcitonin
- On each side of trachea is lobe of thyroid
- connected by an isthmus
- Weighs 1 oz has rich blood supply
35Formation of Thyroid Hormone
- Iodide trapping follicular cells actively take
up iodide ions from blood - Synthesis of thyroglobulin (TGB) RER of
follicular cells make TGB - secreted into the
follicle lumen - Iodination of colloid iodide ions are oxidated
(i.e reform I2) by peroxidase, iodine molecule
then binds onto tyrosine residues on the TGB
known as colloid - this oxidation is required because negatively
charges ions cant bind onto the tyrosine amino
acids - Coupling of T1 and T2 one iodine molecule T1
two iodine molecules T2 - Inside the lumen - form T3 T4
- T2 T2 T4 T1 T2 T3
- Uptake of colloid by follicular cells colloid
reenters the follicular cells by pinocytosis,
merge with lysozymes - digestion of TGB cleaves off T3 and T4 hormones
- Secretion of T3 T4 into blood T3 T4 are
transported in blood bound to thryoxine-binding
globulin (TBG)
36Actions of Thyroid Hormones
- T3 T4 increases metabolic rate
- stimulates synthesis of protein
- stimulates breakdown of fats
- stimulates cholesterol excretion
- increases use of glucose oxygen (ATP
production) - increases body temperature (calorigenic effect)
37Control of T3 T4 Secretion
- Low blood levels of hormones stimulate
hypothalamus -gt TRH - It stimulates pituitary to release TSH
- TSH stimulates thyroid gland to raise blood
levels of T3 and T4 - T3 and T4 regulate themselves through a negative
feedback loop
38Medical application Thyroid disorders
- -hyperthyroidism
- -most common form Graves disease
- 7 to 10 times more common in females
- autoimmune disorder
- antibodies that mimic the action of TSH
- enlargened thyroid and exophthalmos (edema behind
the eyes) - hypothyroidism reduced production of TSH and
thryoid hormones - -common treatment oral L-thyroxin
- - can produce myxedema in the adult
- more common in females
- edema within the facial tissues, slow heart rate,
low body temperature - congenital hypothyroidism
- causes severe mental retardation and stunted bone
growth - babies appear normal due to maternal thyroid
hormones so testing is required
39Parathyroid Glands
- Principal cells (chief cells) produce parathyroid
hormone (PTH) - Oxyphil cell function is unknown
- 4 pea-sized glands found on back of thyroid gland
40Parathyroid Hormone
- Raises blood calcium levels (also regulates Mg
and phosphate levels - increases activity of osteoclasts, increases of
OCs - releases calcium and HPO4 into the blood
- acts on the kidneys to increase reabsorption of
Ca2 back into the blood (also same for Mg) - increases loss of HPO4 into the urine decreases
the overall level of HPO4 in the blood - promotes formation of calcitriol (vitamin D3) by
kidney which increases absorption of Ca2 and
Mg2 by intestinal tract - Opposite function of calcitonin (CT thyroid)
- High or low blood levels of Ca2 stimulate the
release of different hormones --- PTH or CT - high level of calcium in blood - release of
calcitonin by parafollicular cells, promotes
uptake of calcium into bone matrix, lowers blood
calcium - low level of calcium in blood - release of PTH by
parathyroid glands, promotes release of calcium
from bone, raises blood calcium
41Adrenal Glands
- Cortex derived from mesoderm
- Medulla derived from ectoderm
- One on top of each kidney
- 3 x 3 x 1 cm in size and weighs 5 grams
- Cortex produces 3 different types of hormones
from 3 zones of cortex mineralcorticoids
(aldosterone), glucocorticoids (cortisol)
androgens - Medulla produces epinephrine norepinephrine
42AdrenalGland
43Mineralocorticoids
- from the zona glomerulosa of the adrenal cortex
- 95 of these hormones - aldosterone
- Functions
- increase reabsorption of Na with Cl- ,
bicarbonate and water following it - promotes excretion of K and H
- dehydration, hemorrhage (decrease in blood
volume) - decreases blood pressure - secretion of
renin from kidneys which stimulates angiotensin
II release from lungs - stimulates aldosterone
release from adrenal cortex - increases water and
Na uptake from kidneys and increased excretion of
K and H into urine - the increase water reabsorption back into the
blood increases blood volume and pressure - angiotensin II also stimulates contraction of
smooth muscle within arterioles
44Glucocorticoids
- from the zona fasiculata of the adrenal cortex
- 95 of hormonal activity is due to cortisol
- neurosecretory cells secrete corticotropin-releasi
ng hormone (CRH) - CRH promotes the release of ACTH which stimulates
the adrenal cortex to secrete cortisol - Functions helps regulate metabolism provides
resistance to stress - increases rate of protein breakdown lipolysis
- conversion of amino acids to glucose for ATP
synthesis - stimulates lipolysis for ATP synthesis
- provides resistance to stress by making nutrients
available for ATP production - anti-inflammatory effects reduced (skin cream)
- reduces release of histamine from mast cells
- decreases capillary permeability
- depresses phagocytosis
45Androgens
- Small amount of male hormone produced by the zona
reticularis - insignificant in males
- may contribute to sex drive in females
- secreted as dehydroepiandrosterone (DHEA)
- is converted to estrogen in postmenopausal
females - also used by body builders since it is a
precursor to functional testosterone - high dose administration to be useful side
effects? - http//skepdic.com/dhea.html
- http//en.wikipedia.org/wiki/Dehydroepiandrosteron
e
46Adrenal Medulla
- modified sympathetic ganglion part of the ANS!
- the cells lack axons are cluster around blood
vessels - these hormone producing cells Chromaffin cells
receive direct innervation from sympathetic
nervous system - Produce epinephrine norepinephrine
- Hormones are sympathomimetic
- effects mimic those produced by sympathetic NS
- cause fight-flight behavior
- sympathetic preganglionic neurons secrete
acetylcholine - which stimulates secretion by
the adrenal medulla
47Cushings Syndrome
Medical application Adrenal Gland disorders
- Hypersecretion of glucocorticoids
- Redistribution of fat, spindly arms legs due to
muscle loss - Wound healing is poor, bruise easily
Addisons disease
- Hyposecretion of glucocorticoids,
mineralcorticoids - hypoglycemia, muscle weakness, low BP,
dehydration due to decreased Na in blood - mimics skin darkening effects of MSH
- potential cardiac arrest
48Pancreas
- Organ (5 inches) consists of head, body tail
- Cells (99) in acini produce digestive enzymes
- Endocrine cells in pancreatic islets produce
hormones - Exocrine acinar cells surround a small duct
digestive enzymes
49- Endocrine cells secrete near a capillary
- 1 to 2 million pancreatic islets
- Contains 4 types of endocrine cells
- Alpha cells (20) produce glucagon
- Beta cells (70) produce insulin
- Delta cells (5) produce somatostatin or GHIH
- F cells produce pancreatic polypeptide
50Regulation of Glucagon Insulin Secretion
- Low blood glucose stimulates release of glucagon
- High blood glucose stimulates secretion of insulin
51Medical application Diabetes Mellitus
- Diabetes mellitus marked by hyperglycemia
- excessive urine production (polyuria)
- excessive thirst (polydipsia)
- excessive eating (polyphagia)
- Type I----deficiency of insulin (under 20)
- Type II---adult onset
- drug stimulates secretion of insulin by beta
cells - cells may be less sensitive to hormone
52Ovaries and Testes
- Ovaries
- estrogen, progesterone, relaxin inhibin
- regulate reproductive cycle, maintain pregnancy
prepare mammary glands for lactation - Testes
- produce testosterone
- regulate sperm production 2nd sexual
characteristics
53Pineal Gland
- Melatonin secretion produces sleepiness - occurs
during darkness due to lack of stimulation from
sympathetic ganglion
- Small gland attached to 3rd ventricle of brain
- Consists of pinealocytes neuroglia
- Melatonin responsible for setting of biological
clock - Jet lag SAD treatment is bright light
- light strikes retina and stimulates
- suprachiasmatic region of
- hypothalamus
- stimulates sympathetic ganglion
- which then stimulates the
- pineal gland
- light -gt NE -gt no melatonin
- dark -gt lack of NE -gt melatonin
54Thymus Gland
- Important role in maturation of T cells
- Hormones produced by gland promote the
proliferation maturation of T cells - thymosin
- thymic humoral factor
- thymic factor
- thymopoietin
55The stress response
- helpful stress eustress
- stressor any disturbance in the homeostatic
balance of the human body - when homeostasis can counteract these stressors
the body remains within normal physiologic
parameters - if not a series of reactions occurs stress
response - three stages
- 1. initial fight or flight response
- 2. slower resistance reaction
- 3. exhaustion
56- fight or flight
- initiated by nerve impulses of the hypothalamus
to the adrenal medulla (ANS) - release of epinephrine and norepinephrine
- prepares the body for immediate physical response
- short lived response
- resistance
- initiated by hypothalmic releasing hormones
- CRH, GHRH and TRH
- helps the body continue fighting the stressor
- if the body fails to combat the stressor, our
body - enters the last stage
- exhaustion
- resources become depleted so they can no longer
continue the resistance stage - prolonged exposure to cortisol can cause wasting
of skeletal muscle, suppression of the immune
system, ulceration of the GI tract and failure of
the beta cells of the pancreas to make insulin
(diabetes)
-increased blood sugar from breakdown or
neogenesis
-increased glucose used to make ATP and drive
metabolism
57Stress and Disease
- can lead to specific diseases by temporarily
inhibiting the immune system - includes gastritis, ulcerative colitis, irritable
bowel syndrome, migraines, anxiety, hypertension,
asthma, rheumatoid arthritis - role for interleukin-1 (IL-1) which is secreted
by macrophages in the immune system - IL-1 can stimulate secretion of ACTH by the
anterior pituitary - causes production of cortisol
- increased resistance to stress good
- BUT if not controlled exhaustion bad!
58Eicosanoids
- Local hormones released by all body cells
- synthesized from arachidonic acid
- Leukotrienes influence WBCs inflammation
- Prostaglandins alter
- smooth muscle contraction, glandular secretion,
blood flow, platelet function, nerve
transmission, metabolism etc. - Ibuprofen other nonsteroidal anti-inflammatory
drugs treat pain, fever inflammation by
inhibiting prostaglandin synthesis
59Nonsteroidal Anti-inflammatory Drugs
- Answer to how aspirin or ibuprofen works was
discovered in 1971 - inhibit a key enzyme in prostaglandin synthesis
(COX) without affecting the synthesis of
leukotrienes - Treat a variety of inflammatory disorders
- rheumatoid arthritis
60Aging and the Endocrine System
- Production of human growth hormone decreases
- muscle atrophy
- Production of TSH increase with age to try and
stimulate thyroid - decrease in metabolic rate, increase in body fat
hypothyroidism - Thymus after puberty is replaced with adipose
- Adrenal glands produce less cortisol
aldosterone - Receptor sensitivity to glucose declines
- Ovaries no longer respond to gonadotropins
- decreased output of estrogen (osteoporosis
atherosclerosis)