Chapter 16 Endocrine - part 2
Endocrine system
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several separate organs
release hormone into capillaries
hormone transported in blood
endocrine vs exocrine
Endocrine Glands
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Hypothalamus
Pituitary
Pineal gland
Thyroid
Parathyroid
Thymus
Adrenal Cortex
Adrenal Medulla
Pancreas
Ovary
Testes
several others
things to know
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endocrine gland
gland + hormone(s) produced
hormone + its action
diseases
types of hormones
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direct hormones
target = non-endocrine tissue
tropic hormones
target = endocrine glands
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releasing hormones
from hypothalamus
stimulating hormones
from ant. pituitary
prohormone
inactive forms
Thyroid gland
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follicular cells
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lumen
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parafollicular (C) cells
• produce thyroid hormone
• stores colloid
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produce calcitonin
Thyroid hormone
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thyroid hormone
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effects:
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calorigenic
thyroxine
tri-iodothyronine T3
T4
stim gene/enzymes of cell respiration
uncoupling enzymes
increase basal metabolic rate = heat
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metabolic
protein synthesis
increase heart rate
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growth
nervous system development
muscle, skeletal development
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see table 16.2
and BP
Thyroid hormone synthesis
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thyroglobulin synthesis
iodination
I2 added to tyrosine
storage
colloid = thyroglobin + I2
cleavage
T4 and T3 break from colloid
stim by TSH
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secretion
exocytosis
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transport
TBG
thyroxine-binding globulin
control of T4
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stimulus:
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(thyroid stimulating hormone)
low blood T4
low body temp
pregnancy
inhibited by
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TSH
any inhibition of TSH
high blood T4
somatostatin
Diseases of Thyroid hormone
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Grave’s Disease
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 BMR ;  HR
weight loss ; sweating
exopthalmos
Myxedema
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weakness; lethargy ; mental “sluggishness”
 BMR ; weight gain ; chilled
Cretinism
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Goiter
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hypothyroidism (adult)
fluid accumulation
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hyperthyroidism
hypothyroidism (congenital)
decreased growth; and mental development
thyroid tumor
decreased I2
increased TSH  increase colloid
Calcitonin
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= thyrocalcitonin
parafollicular (C) cells
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effects:
decrease blood calcium
deposit calcium into bone
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stimulus:
high blood Calcium
Parathryroid gland
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Parathyroid hormone
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PTH = parathormone
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effects :
increase blood calcium
increase Ca++ absorption
increase Ca++ reabsorption
remove Ca++ from bone
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stimulus:
low blood calcium
Adrenal gland
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2 separate glands
adrenal cortex
adrenal medulla
outer
inner
Adrenal medulla
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2 catecholamines
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effects:
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epinephrine
norepinephrine
“adrenaline rush” “fight or flight”
increase heart rate , BP
bronchodilation
increase BMR
increase alertness
increase blood glucose
stimulus:
Sympathetic nervous system
Adrenal cortex hormones
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hormones:
corticosteroids
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mineralcorticoids
aldosterone
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glucocorticoids
cortisol
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gonadocorticoids
androgens
mineralcorticoids
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aldosterone
effects:
increases Na levels in blood and tissue fluid
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stim transcription of Na-K ATPase in kidney
increases reabsorption Na+ into blood
increase blood volume
increase BP
stimulus:
renin-angiotensin
low blood Na
ACTH
glucocorticoids
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“stress hormone”
cortisol
“ glucose sparing”
• increase blood glucose
• fat catabolism
glycogenolysis
gluconeogenesis
protein catabolism
more AA for repair
anti-inflammatory
limit immune system
affects memory
stimulus:
ACTH
stress
inflammation
Gonadocorticoids
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androgens :
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males
convert to testosterone
female
convert to estradiol
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effects:
puberty
sex drive
minimal compared to gonad production
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Cushing’s
increased Cortisol
Diseases of Adrenal Cortex
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ACTH producing tumor
ant pituitary , lung
pharmaceutical doses
cushingoid features:
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Addison’s Disease
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pheochromocytoma
moon face : buffalo hump
steroid diabetes
osteoporosis - fractures
low inflammatory response
decreased Aldosterone , Cortisol
• low Na ; increase K levels
• low BP
• hypoglycemia
Diseases of Adrenal Medulla
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chromaffin cell tumor
increased epinephrine effects
Pancreas
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pancreatic islets
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islets of Langerhans
alpha (α) cells
glucagon
beta (β) cells
insulin
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somatostatin
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effects:
Glucagon
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liver -
stimulus:
increase blood glucose
glycogenolysis
gluconeogenesis
lipolysis
low blood glucose
sympathetic n.s.
Insulin
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effects:
the most anabolic hormone
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increase membrane transport of glucose
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decrease blood glucose
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• increase glycogenesis (storage)
• increase protein synthesis and lipogenesis
• increase carrier proteins
GLUT4
increase cell respiration
decrease gluconeogenesis , lipolysis
stimulus:
high blood glucose
parasympathetic n.s.
glucagon
Insulin production
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glucose enters beta cells
GLUT2 channel
increases cell respiration - ATP
ATP closes K+ channels - depolarization
depolar opens voltage gated Ca++ channels
Ca++ enters beta cell
Ca++ stim exocytosis of insulin
somatostatin
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same as hypothalamic hormone (GHIH)
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inhibits GH (growth hormone)
inhibit TSH (thyroxine)
inhibit gastric activity
glucose related hormones
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decrease blood glucose :
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insulin
increase blood glucose :
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glucagon
for body if low glucose
epinephrine
for N.S. if immediate stress
cortisol
for N.S. if long term stress
growth hormone
for growth
thyroxine
for cell respiration, heat
Diseases of Pancreas
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hypoglycemia =
low blood glucose
hyperglycemia
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high blood glucose
• glucosuria
• Polyuria
• Polydipsia
• Polyphagia
Diabetes Mellitus
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type 1
hyperglycemia
Insulin dependent
– congenital (autoimmune)
type 2
non Insulin dependent
IDDM
decrease Beta cells
NIDDM
– developed
– decrease Insulin receptors on target cells
Thymus
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thymic hormones
maturation of T lymphocytes
Pineal gland
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= epithalamus
melatonin
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circadian rhythms
inhibit RAS
stim by hypothalamus
Ovary
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estradiol
follicle
progesterone
corpus luteum
Ovary
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estradiol
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effects:
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stimulus: FSH
progesterone
follicle
ovum development
uterus development
mammary duct development
corpus luteum , placenta
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effects:
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stimulus: LH , hCG
inhibin
uterus development
mammary gland development
inhibits FSH, LH
Testes
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testosterone
interstitial cells
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effects:
sperm maturation
accessory sex glands
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stimulus:
ICSH
inhibin
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effects:
sustentacular cells
inhibits FSH
Hypothalamus
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“master gland” of the endocrine system
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direct hormones
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ADH = antidiuretic hormone
urine concentration
decrease blood Osm
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oxytocin
uterine contractions
milk secretion
regulatory hormones
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controls Pituitary gland
RH = releasing hormones (factors)
IH = inhibitory hormones
Pituitary
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= Hypophysis
Posterior Pituitary
neurohypophysis
• neural connection to hypothalamus
Anterior Pituitary
adenohypophysis
• blood connection to hypothalamus
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Posterior Pituitary
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extension of the Hypothalamus
hypothalamic-hypophyseal tract
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axons from Hypothalamus
hormones made in hypothalamus
released from posterior pituitary
Posterior Pituitary
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ADH
Antidiuretic hormone
(vasopressin)
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effects:
increase water reabsorption – kidney
decrease blood Osm
increase blood volume, BP
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stimulus:
increase osmolarity
oxytocin
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effects:
uterine contractions
milk release
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stimulus:
stretch of uterus
nursing
Anterior Pituitary
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= adenohypophysis
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hypophyseal portal system
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direct hormones
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stimulating hormones
• vascular system betw hypothalamus and ant. pituitary
specific body responses
control other endocrine glands
Anterior Pituitary – direct hormones
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GH growth hormone =
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effects:
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stim:
somatotropic hormone
mitosis
protein synthesis
Insulin-like growth factors
increase blood glucose
GHRH ; low GH ; exercise
PRL prolactin
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LH
effect:
milk production
stim
nursing
PRH
luteinizing hormone
ovulation
Anterior Pituitary – stimulating hormones
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TSH
thyroid stimulating hormone
thyrotropin
ACTH
adrenocorticotropic hormone
corticotropin
FSH
follicle stimulating hormone
folliculotropin
LH
luteinizing hormone
luteotropin
ICSH
interstitial cell stimulating hormone
GH
somatotropin
these stimulate target tissue to
release hormone ; grow
controlled by Releasing hormones from hypothalamus
stimulating hormone effect
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ant pituitary
TSH
ACTH
FSH
LH
ICSH
GH
other endocrine glands
thyroid
thyroxine
adrenal cortex
cortisol
follicle
estrogen
corpus luteum
progesterone
interstitial cells testosterone
liver
insulin-like growth factors
hypothalamus – releasing factors
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hypothalamus
growth hormoneRH
prolactin RH
corticotropicRH
thyrotropicRH
gonadotropicRH
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growth hormoneIH
gonadotropicIH
ant. pituitary
GHRH
GH
PRH
PRL
CRH
ACTH
TRH
TSH
GnRH (FHRH) FSH
GnRH (LHRH) LH
GHIH
inhibit GH
GnIH
inhibit FSH, LH
** hypothalamus controls all pituitary production there is a regulating hormone from hypothalamus for every pituitary hormone
Who’s the Boss ?
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master gland?
“private controls the general”
target gland hormones control the hypothalamus and anterior pituitary
negative feedback
positive feedback:
estradiol stim LH for ovulation
not so during pregnancy
diseases of Growth Hormone
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increased GH:
Gigantism
• increased length of long bones
• congenital
Acromegaly
• increased size of facial bones, hands
• pituitary tumor ; adult
decreased GH:
Pituitary Dwarfism
• decreased height ; normal proportions
• congenital
other endocrine structures
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heart
atrial natriuretic peptide
kidney
renin
erythropoietin
calcitriol
brain
brain natriuretic peptide
skin
cholecalciferol (Vitamin D)
liver
angiotensin
digestive tract
gastrin
secretin
cholecystokinin
adipose
ANP
BNP
estrogens
BP hormones
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antidiuretic hormone
raise BP
epinephrine
raise BP
cortisol
raise BP
renin-angiotensin
raise BP
thyroxine
raise BP
atrial natriuretic peptide
lower BP
endocrine reflex path
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control reflex path from stimulus to response
stimulus
=
change in condition
afferent signal
stimulus - change in condition
receptor
endocrine gland
integration
endocrine gland
efferent signal
hormone
effector
organ , tissue response