the the endocrine endocrine systemsystem · the endocrine system from: costanzo, physiology, 5th...
TRANSCRIPT
2020.02.25.
1
The The EndocrineEndocrine SystemSystem
Judit Rosta
21. 02. 2020
Evening seminarEvening seminar-- PhysiologyPhysiology
Learning Obj.: 71,72,73
Evening seminar-Physiology-Endocrin.
The Endocrine System
From: Costanzo, Physiology, 5th Edition Elsevier
2020.02.25.
2
MulticellularMulticellular LifeLife
1) Hormone synthesis, storage, release
2) Define neurosecretion.
3) Hormone secretion control
4) Hormonal effects: stimulatory, inhibitory, permissive effects
Learning Obj.: 71,72,73
Cell-cell
Paracrine
Endocrine (vs.exocrine)
Principles of endocrine control systems
Evening seminar-Physiology-Endocrin.
Synthesis Storage Release Receptor/
Target
Glycoproteins/Peptides
trophichormones…
In advance Vesicles Exocytosis Membranereceptor
Steroids cortisol, aldosterone
On demand No (cholesterol/HD
L,LDL)
Diffusion Intracellular/Nuclear receptor
Aminehormones
T3,T4 In advance Vesicles/follicle Transporter NuclearTR/Transporter(B
BB)
The Classification of Hormones
Based on chemical structure
Hormone synthesis, storage, release
2020.02.25.
3
Evening seminar-Physiology-Endocrin.
Learn.Obj.2. State Fick’s law of diffusion. Transport rate:
driving forces (chemical and electrical gradient)
membrane properties
secretion rate of a hormone depends on its synthesis
Hormone synthesis, storage, release
Steroids - release
Cholesterol+enzyme activity
Bound hormones : Free hormones
e.g. hepatic failure: TBG ↓= free hormone↑
1 picogr-1 microgram/ml
Hormones in circulation:
HYPOTHALAMOHYPOTHALAMO--HYPOPHYSEAL PORTAL SYSTEMHYPOPHYSEAL PORTAL SYSTEM
Neurosecretion
Trophic hormones(their presence or absence causesother
organs to grow or atrophy)
The synthesis and release of hormones by neurons (neurohormones)
Hypothalamus: neurons receive nerve impulses
from other parts of the brain but transmit signals
to the pituitary gland by neurohormones that are
released into the blood
neurotransmitter vs. neurohormone
Portal vessels (after passing through one
capillary bed, conveyed through a second
capillary network- e.g. hepatic portal system)
CRH
GnRH
PIH
FSH,LH GH
ACTH
PRL
TSH
Ad
en
oh
yp
op
hysis
:
tro
ph
ic h
orm
on
es
neu
roh
yp
op
hysis
Optic chiasma
Neu
rosecre
tory
cells
:
rele
asin
gh
orm
on
es
Neurosecretory cells:ADH,oxytocin
Su
p.h
yp
op
hys.a
rt.
Portal veins
2020.02.25.
4
Evening seminar-Physiology-Endocrin.
Hormone Secretion Control
Learning Obj.
1. Principles of control theory.
Regulation (humoral, neural): Guidance vs. Control
Positive Feed Back: blood clotting, Ferguson (oxytocin) reflex
Negative feed back: HCO3--secretin
Feed forward:
Endocrine Feedback Loop
Gastric acid secretion- cephalic/oral phase
(endocrine, paracrine, neural components)
from Prof.Sáry (Phys.lecture 1st)
Evening seminar-Physiology-Endocrin.
The Endocrine System
From: Costanzo, Physiology, 5th Edition Elsevier
2020.02.25.
5
Hormone Secretion Control
Negative Feedback
e.g. pancreas and parathyroid gland
controlled by the regulated variable
(e.g. blood glucose and calcium)
Gardner DG, Shoback D.: GreenspanBasic & Clinical Endocrinology, 9thEdition
PTH ↑
Calcium Feedback to Regulate Parathyroid Hormone (PTH)
Secretion
Endocrine Feedback Loop
Osteoclasts, distal tubules, kidney (vitamin D)
Ca++-sensor on parathyroid cells
↓ Blood calcium
-
Blood calcium ↑
-
Evening seminar-Physiology-Endocrin.
The Endocrine System
From: Costanzo, Physiology, 5th Edition Elsevier
2020.02.25.
6
Hormone Secretion Control
Hypothalamic Releasing and Inhibiting Hormones
Endocrine Feedback Loop
Thyroid gland
1. how the hypothalamus
controls the anterior
pituitary through
hormone secretion
2. how the anterior pituitary
controls the target tissue
through hormone
secretion.
3. how tissue hormones
provide negative feedback to the
hypothalamus and
anterior pituitary
TRHTRH-receptor
Released TSH
Hormone Secretion ControlEndocrine
Feedback Loop
Thyroid gland
Graves’ Disease-TSH
receptor autoantibodies-
excess negative feed
back, supresses TSH
TSH:thyrotropin
2020.02.25.
7
Evening seminar-Physiology-Endocrin.
The Endocrine System
From: Costanzo, Physiology, 5th Edition Elsevier
Hormone Secretion Control
Hypothalamic Releasing
and Inhibiting Hormones
Endocrine Feedback Loop
Positive feedback
causes additional
secretion of the
hormone-until an
appropriate
concentration
Hormonal Profile of
EstradiolEstradiol, , LH LH and FSHand FSH
Sustained increase in estradiol in the late follicular phase triggers
the massive burst of LH secretion that just precedes ovulation
Estradiol has + Feedback on LH
2020.02.25.
8
Evening seminar-Physiology-Endocrin.
The Endocrine System
From: Costanzo, Physiology, 5th Edition Elsevier
Regulation of Prolactin Secretion
Prolactin inhibits itsown secretion byincreasing the secretionof dopamine
Hormone Secretion Control
Hypothalamic Releasing
and Inhibiting Hormones
Endocrine Feedback Loop
Prolactin has + Feedback on PROLACTIN
INHIBITING FACTOR (dopamine)
2020.02.25.
9
Evening seminar-Physiology-Endocrin.
The Endocrine System
From: Costanzo, Physiology, 5th Edition Elsevier
consequence of feedback control
Gardner DG, Shoback D.: Greenspan Basic & Clinical Endocrinology, 9th Edition
ACTHACTH--CortisoCortisol
Pulsatory Pattern: burst-like manner
Hormone Secretion Control
by Pascale M Y Smets
ACTH � Cortisol � metabolic effectsmin hours
CORTISOL has – Feedback on
ACTH Hypothalamic Releasing and Inhibiting Hormones
Endocrine Feedback Loop
stress
2020.02.25.
10
Evening seminar-Physiology-Endocrin.
The Endocrine System
From: Costanzo, Physiology, 5th Edition Elsevier
Hormone Secretion- Regulation Inefficiency
ADH ADH SecretionSecretion
ADH neurons
Plasma osmolarity
increases
Plasma osmolarity
decreases
Water reabsorption
in collecting ducts
Nucl.
supraopticus
ADH ADH releaserelease
Posterior
pituitary
Plasma osmolality ↑
ANP
alcohol
baroreceptors
Na+ cc.
Case report:
56-year-old man with
lung carcinoma
experienced a grand mal
seizure and became
semicomatose
Tests:
serum Na+, Cl-:low
serum K+: normal
urine Na+, Cl-:normal
Osmolarity: 225 mOsm/L
Hypothalamic
osmorceptors
2020.02.25.
11
Explanation:
Seizure caused by swelling of brain cells-excess water reabsorbed by the kidney was
distributed throughout the ICF-water flowed into the cells, their volume increased-(fixed
cavity the skulll)
Treatment:
Hypertonic NaCl is infused�raise the osmolarity; administration of ADH antagonist
Small cell carcinoma: ADH
secreting tumor cells
Low osmolality: Na+-reabsorption ↓ or water reabsortion ↑
Inappropriate secretion of the
antidiuretic hormone (ADH)
(Aldosteron)
Urine Na+: normal
(ADH)
?
Ectopic production of ADH
Hormone Secretion- Regulation Inefficiency
the presence of one hormone, at a certain
concentration, is required in order to allow a
second hormone to fully affect the target cell
Hormones which exert permissive effect on:
Estrogen the formation of receptor proteins for progesterone in
uterus
Parathyroid hormone the synthesis of vitamin D3
(via stimulation of the production of the hydroxylating
enzymes in the kidneys and liver)
Cortisol: glucagon induced gluconeogenesis
Thyroid hormones: anabolic and metabolic effects of Growth Hormone
Hormonal effects: permissive effect
2020.02.25.
12
• Increase adrenergic receptor synthesis
• Enhanced binding of the receptor to the G-protein
• Increased catecholamine-induced cAMP formation
• Prolonged effect of catecholamine on smooth muscles
Hormonal effects: permissive effect
Vasoconstriction, positive inotropic effect
Glucocorticoids are needed to the
maintenance of normal blood
pressure!
CORTISOL exerts permissive
effect on the actions of
catecholaminesatecholamines
keeps vasculatura and arterioles partially
constricted and this maintains blood
pressure
(regulating amount of blood flow into the
capillaries)
α1
BLOOD VESSELS
WITHOUT DUAL
INNERVATION-SYM
TONE
2020.02.25.
13
Evening seminar-Physiology-Endocrin.
Glucocorticoid ↑= Cushing syndrome: Hypertension vasoconstriciton
Hormonal effects:
CORTISOL
46. The regulation of local blood flow.
Cortisol -
hormones work together to
produce a particular result
epinephrine+norepinephrine on cardiac rate- together even greater
increase than the sum of their individual effects (additive)
testosterone+FSH-each stimulates different stages of
spermatogenezis, both needed to complete sperm development
(complementary)
Hormonal effects: Synergistic Effect
2020.02.25.
14
Synergism between THYROID
Hormones and Catecholaminesatecholamines
increases β1 adrenergic
receptor induced cAMP
formation
Hormonal effects:
thyroid hormones
α,β adrenergic receptors
cAMP
increases β1 adrenergic receptor mediated cAMP formation
Hormonal effects:THYROID Hormones
Tachycardia: clinical importance- whether a patient has
excessive or diminished thyroid hormone production
increased heart strength via formation of myosin
Na/Ca-exchanger inhibition
CHRONOTROPIC EFFECTCHRONOTROPIC EFFECT
pulse pressure is increased (systolic pressure is
elevated 10 to 15 mm Hg)
INOTROPIC EFFECTINOTROPIC EFFECT
Hyperthyroidism:
Cardiovascular effects
+/− heart effects
LUSITROPIC EFFECTLUSITROPIC EFFECT SERCA upregulation
Appropriate thyroid hormone level is
required for optimal heart functions
2020.02.25.
15
Hormonal effects:THYROID Hormones
Phys Heart I. Prof.Sáry Obj.35.
increases β1 adrenergic receptor mediated cAMP formation
increased heart strength via formation of myosin
Na/Ca-exchanger inhibition
CHRONOTROPIC EFFECTCHRONOTROPIC EFFECT
INOTROPIC EFFECTINOTROPIC EFFECT
LUSITROPIC EFFECTLUSITROPIC EFFECT SERCA upregulation
Evening seminar-Physiology-Endocrin.