the endocrine system michael hall phd university of california los angeles university of california...
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The Endocrine SystemThe Endocrine SystemThe Endocrine SystemThe Endocrine System
Michael Hall PhDMichael Hall PhDMichael Hall PhDMichael Hall PhD
University of CaliforniaUniversity of CaliforniaLos AngelesLos Angeles
University of CaliforniaUniversity of CaliforniaLos AngelesLos Angeles
Modes of secretion and action of chemical messengers
(hormones)
Modes of secretion and action of chemical messengers
(hormones)autocrine paracrine endocrine synaptic
target cell
target cellChemical messenger
receptors
Classes of Chemical MessengersClasses of Chemical Messengers
1.1. Amino acid derivatives (eg thyroxine, adrenaline)Amino acid derivatives (eg thyroxine, adrenaline)2.2. Small peptides (eg vasopressin, thyroid releasingSmall peptides (eg vasopressin, thyroid releasing
hormone)hormone)3. Proteins (eg insulin, growth hormone)3. Proteins (eg insulin, growth hormone)4. Steroids (eg cortisol, testosterone, progesterone)4. Steroids (eg cortisol, testosterone, progesterone)
Positive and negative feedback control of hormone production
Positive and negative feedback control of hormone production
Higher brain centersHigher brain centers Higher brain centersHigher brain centers
HypothalamusHypothalamus HypothalamusHypothalamus
Anterior Pituitary Anterior Pituitary
Adrenal cortexAdrenal cortex
Adrenal medullaAdrenal medulla
EpinephrineEpinephrine
Anterior PituitaryAnterior Pituitary
Thyroid follicular cellsThyroid follicular cells
Various tissuesVarious tissues
neurotransmittersneurotransmittersneurotransmittersneurotransmitters
TRHTRH CRHCRH
TSHTSH ACTHACTH
T3/T4T3/T4 CortisolCortisol
Various tissuesVarious tissues
Sensory neuronal stimulation Sensory neuronal stimulation
DDiffuse iffuse NNeuroeuroEEndocrine ndocrine SSystemystem
The DNES involves a number of isolated cells, The DNES involves a number of isolated cells, or small groups of cells, that are situatedor small groups of cells, that are situatedthroughout the body, but particularly in thethroughout the body, but particularly in thedigestive, respiratory and urinary systems. These digestive, respiratory and urinary systems. These cells, called APUD cells, secrete chemical cells, called APUD cells, secrete chemical messengers that generally act in a paracrine manner.messengers that generally act in a paracrine manner.
The Endocrine Glands
Most organs have some endocrine function. The next lectures will deal with organs whose only functions are to secrete hormones:
PituitaryThyroidParathyroidAdrenalPancreas*
*Pancreas has both endocrine and exocrine functions
The Endocrine Glands
Most organs have some endocrine function. The next lectures will deal with organs whose only functions are to secrete hormones:
PituitaryThyroidParathyroidAdrenalPancreas*
*Pancreas has both endocrine and exocrine functions
Pituitary GlandPituitary GlandPituitary GlandPituitary Gland
Pituitary hormones and their target organsPituitary hormones and their target organsPituitary hormones and their target organsPituitary hormones and their target organs
Development of the pituitary glandDevelopment of the pituitary gland
infundibulum(stalk)
median eminence
hypothalamus
pars nervosa
pars tuberalis
medianeminence
hypothalamus
infundibulum(stalk)
pars nervosa
pars distalis
pars intermedia
Hypothalamus and PituitaryHypothalamus and Pituitary
posterior anterior
Hormone production and release by the neurohypophysis
Hormone production and release by the neurohypophysis
(pars nervosa)
(pars distalis)
(oxytocin)
(ADH)
Herring bodyHerring body
Pituicytes (glial cells)Pituicytes (glial cells)
Herring body in neurohypophysisHerring body in neurohypophysis
Herring Bodies along a CapillaryHerring Bodies along a Capillary
Secretory granule
Axon terminal
Capillary
Secretory granule
Axon terminal
Capillary
pars tuberalis
medianeminence
hypothalamus
infundibulum(stalk)
pars nervosa
pars distalis
pars intermedia
Hypothalamus and PituitaryHypothalamus and Pituitary
posterior anterior
Development of the pituitary glandDevelopment of the pituitary gland
infundibulum(stalk)
median eminence
hypothalamus
pars nervosa
ChromophobesChromophobes
AcidophilsAcidophils
Chromophils and Chromophobesin the Adenohypophysis
Chromophils and Chromophobesin the Adenohypophysis
capillarycapillary
BasophilsBasophils Ch
rom
oph
ils
Ch
rom
oph
ils
pars tuberalis
medianeminence
hypothalamus
infundibulum(stalk)
pars nervosa
pars distalis
pars intermedia
Hypothalamus and PituitaryHypothalamus and Pituitary
posterior anterior
Infundibulum
Pars tuberalis
PituitaryPars tuberalis and portal veins
PituitaryPars tuberalis and portal veins
Portal veins
pars tuberalis
medianeminence
hypothalamus
infundibulum
pars nervosa
pars distalis
pars intermedia
Hypothalamus and PituitaryHypothalamus and Pituitary
posterior anterior
The Insignificant Middle Lobe
Hypophyseal portal systemHypophyseal portal system
1
2
3
4
Infundibulum
Pars tuberalis
PituitaryPars tuberalis and portal veins
PituitaryPars tuberalis and portal veins
HypophysealHypophysealportal veinsportal veins
Pituitary hormones and their target organsPituitary hormones and their target organsPituitary hormones and their target organsPituitary hormones and their target organs
Thyroid GlandThyroid Gland
Thyroid gland
Parathyroid gland
Parafollicularcell
Follicularcell
Colloid
Oxyphil cell
Chief cell
Thyroid and parathyroid glandsThyroid and parathyroid glands
CT
lobule
F
Two thyroid lobules separated by CT septumTwo thyroid lobules separated by CT septum
Thyroid Follicles
capillaries
Follicular cells
thyroglobulin
Basementmembrane
A. Synthesis and iodination of thyroglobulinB. Release of thyroxine (T3 and T4)A. Synthesis and iodination of thyroglobulinB. Release of thyroxine (T3 and T4)
A B
TRHTRH
TSHTSH
T3/T4T3/T4
IodineIodine
TRHTRH
Excess TSHExcess TSH
Low T4
IodineIodine
Neg
ativ
e fe
edba
ckN
egat
ive
feed
back
Low
Neg
ativ
e fe
edba
ckL
ow N
egat
ive
feed
back
hypothalamus hypothalamusIodineIodinedeficiencydeficiencygoitergoiter
Iodine deficiency Iodine deficiency goitergoiterIodine deficiency Iodine deficiency goitergoiter
Parafollicular cells in the thyroidParafollicular cells in the thyroid
Inhibits osteoclasts
stimulates osteoclasts
Action of calcitonin and PTH in blood calcium homeostasis
Action of calcitonin and PTH in blood calcium homeostasis
Thyroid
Parathyroid
Parathyroids are situated on the posterior surface of the thyroid gland
Parathyroids are situated on the posterior surface of the thyroid gland
ParathyroidParathyroid
Parathyroid and thyroid glandsParathyroid and thyroid glands
Cells of the parathyroidCells of the parathyroid
Oxyphil cells
Chief cells
Inhibits osteoclasts
stimulates osteoclasts
Interaction of calcitonin and PTH in blood calcium homeostasis
Interaction of calcitonin and PTH in blood calcium homeostasis
Adrenal GlandAdrenal Gland
Z. glomerulosaZ. glomerulosa
Z. fasciculataZ. fasciculata
Z. reticularisZ. reticularis
MedullaMedulla
CapsuleCapsule
Co
rtex
Co
rtex
AdrenalAdrenal
Capsule
Z. glomerulosaZ. glomerulosa
Z. fasciculataZ. fasciculata
Z. reticularisZ. reticularis
MedullaMedulla
Mineralocorticoids(e.g. aldosterone)
Sex hormonesSex hormonese.g. e.g. DHEADHEA
AdrenalineAdrenaline
NoradrenalineNoradrenaline
Hormones
cap
GlucocorticoidsGlucocorticoidse.g. cortisole.g. cortisol
Preganglionicsympathetic terminal
Z. glomerulosaZ. glomerulosa
Z. fasciculataZ. fasciculata
Z. reticularisZ. reticularis
MedullaMedulla
CapsuleCapsule
Co
rtex
Co
rtex
AdrenalAdrenal
Capsule
Z. glomerulosaZ. glomerulosa
Z. fasciculataZ. fasciculata
Z. reticularisZ. reticularis
Medulla
Mineralocorticoids(eg. aldosterone)
Glucocorticoids(eg cortisone)
Sex hormones(eg DHEA)
Adrenaline
Noradrenaline
Hormones
capPreganglionicsympathetic neuron
Chromaffin cellsChromaffin cells
Postganglionicparasympathetic neurons
Postganglionicparasympathetic neurons
Cells of the adrenal medullaCells of the adrenal medulla
Capsule Subcapsular arterial plexus
Fenestrated sinusoids
Medullary artery
Medullary vein
Adrenal Blood SupplyAdrenal Blood Supply
Z. glomerulosa.Z. glomerulosa.
Z. fasciculata.Z. fasciculata.
Medulla.Medulla.
Z. reticularis.Z. reticularis.
Arterial and Venous blood in AdrenalArterial and Venous blood in Adrenal
PancreasPancreas
Islet of Langerhans in PancreasIslet of Langerhans in Pancreas
IsletIsletIsletIslet
Acinar cellsAcinar cellsAcinar cellsAcinar cells
Cells and hormones of the Cells and hormones of the pancreatic isletspancreatic islets
1.1. -cells secrete insulin (causes decrease in blood glucose)-cells secrete insulin (causes decrease in blood glucose)
2.2. -cells secrete glucagon (causes breakdown of glycogen-cells secrete glucagon (causes breakdown of glycogenand increase of blood sugar)and increase of blood sugar)
3. 3. -cells secrete somatostatin (has both paracrine [inhibits -cells secrete somatostatin (has both paracrine [inhibits release of insulin and glucagon] and endocrine effects release of insulin and glucagon] and endocrine effects [reduces motility of smooth muscle of gut])[reduces motility of smooth muscle of gut])
4. G-cells secrete gastrin (stimulates release of HCl from 4. G-cells secrete gastrin (stimulates release of HCl from parietal cells of stomachparietal cells of stomach
5. PP-cells secrete pancreatic polypeptide (inhibits exocrine5. PP-cells secrete pancreatic polypeptide (inhibits exocrine secretion of pancreatic enzymes)secretion of pancreatic enzymes)
C’est toutC’est tout
GUT LIVER
TYPES OF TYPES OF MICROCIRCULATIONMICROCIRCULATION
Typical arrangementTypical arrangement
Venous Portal systemVenous Portal system
Arterial portal systemArterial portal system
Hormone production and release by the neurohypophysis
Hormone production and release by the neurohypophysis
(pars nervosa)
(pars distalis)
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