Transcript Department of Anatomy ppt

Endocrine glands
Morphology and embryology
Course: Endocrine system
David Kachlik and Petr Zach
Endocrine glands
Glandulae endocrinae
► One
of regulatory systems
► hormone (greek horman – to awake, stimulate)
 Chemical messenger produced by endocrine
gland and transported by blood to target organs
 proteins (polypeptides) - insulin
 Biogennic amines - adrenalin
 steroids - estrogens
Endocrine glands
History
► Thomas
Wharton
► 1614-1673
► 'Adenographia‚
► First detailed
description of endocrine
glands
Endocrine glands
History
► Ernest
Henry Starling
► 1866-1927
► Created general rules of
„internal secretion “
► He used already existing
word „hormones“
 Sir William Bate Hardy,
physiologist from Cambridge
Endocrine glands
Organization
1.
2.
3.
glands
Disseminated cells
neuroendocrine cells
Endocrine glands
Glands
► Hypothalamus
► Hypophysis;
Gl. pituitaria
► Glandula thyroidea, thyroid gland
► Gll. parathyroideales
► Gll.
Suprarenales, suprarenal gland
► Langerhans islets (Insulae pancreaticae)
► Gl. pinealis; Corpus pineale
Hypothalamus + hypophysis
Systema
hypothalamo-hypophysiale
Hypotalamo-hypophyseal
axis
Hypophysis; Glandula pituitaria
History
► Galén
– mucus produced for nasal mucosa
► Schneider – 1655 rejects Galén theory
► Minkowski, Hutchinson – connection
between growth problems and hypertrophy
of hypophysis
► Cushing – explained function of hypophysis
„dirigent of endocrine system, minister head“
Hypothalamus
part of diencephalon (Diencephalon),
bazally to IIIrd ventricle
► Function
► Bazal




Gathers info from body and surroundings
Highest autonomic center (vegetative)
Part of limbic system
Directs other endocrine glands
► Corpora
mamillaria, tuber cinereum,
infundibulum, hypophysis
Hypothalamus
► Anterior
hypothalamus – ncl.
magnocellularis
 Ncl. paraventricularis + supraopticus – oxytocin
and vasopressin (ADH)
► Middle
hypothalamus (tuber cinereum) –
ncl. parvocelularis
 Ncl. arcuatus – regulation of adenohypophysis
► Posterior
hypothalamus
Hypothalamus - Hormones
► Ncl.
arcuatus - production
► Eminetia mediana – release into first
capillary bedstream
► Releasing
hormones (releasing)
 SRH, PRH, GnRH, TRH, CRH
► Supressing
hormones (inhibiting)
 somatostatin, PIH (= dopamin)
Hypophysis - anatomy
► Formed
by two lobes
 ventral - adenohypophysis
 dorsal – neurohypophysis
in sella turcica ossis sphenoidalis
► Covered by dura mater – diaphragma sellae
► Located
 foramen diaphragmatis Pacchioni – for
hypophyseal infundibulum
► Transsphenoid
approach
Hypophysis - anatomy
lobe (Adenohypophysis; Lobus
anterior)
► Ventral
 Pars distalis (principalis) – biggest
 Pars intermedia – between both lobes
 Pars tuberalis – part by infundibulum
lobe (Neurohypohysis; Lobus
posterior)
► Posterior
 Lobus nervosus (Pars nervosa) – proper
posterior lobe
 Infundibulum – stalk leading to hypotalamus
Blood supply of hypophysis
► Hypophyseal
portal system
 A. hypophysialis inferior (from pars cavernosa to
neurohypophysis)
 A. hypophysialis superior (from pars cerebralis
via hypothalamus into adenohypophysis)
► Vv.
hypophysiales into sinus cavernosus
Hypophysis - development
► Ratkhe
pouch (from ectoderm)
 3rd week – in the roof of mouth cavity
 Exagination towards diencephalon
 Separation of exagination, proliferation of
ventral wall
► Exagination
of basis of diencephalon
 Creates posterior lobe
 Differentiation into pituicytes (glia)
Hypophysis - development
Hypophysis - development
Ventral lobe = Adenohypophysis
► Pars
distalis
 biggest (75%)
► Pars
tuberalis
 cranially
► Pars
intermedia
 between adeno- and neurohypophysis
Pars distalis adenohypophysis
of cells (chordae endocrinocytorum),
between them capillaries
► on HE 3 types of cells
► Strand
 acidophilic
 bazophilic
►PAS-pozitive
 chromophobic
►w/o
granules, non-differentiated elements
Pars distalis – Acidophilic cells
►α
– cells (Endocrinocytus somatotropicus)
 Rough granules, GER
 Around nucleus zone w/o granules - GA
 Growth hormone (somatotropin, GH)
►ε
– cells (Endocrinocytus prolactinicus)
 Usually small, not numerous (x gravidity,
lactation)
 Small granules (enlargement in gravidity)
 prolaktin (PRL)
Pars distalis – bazophilic cells
► β1 –
cells (Endocrinocytus corticotropicus)
 Big granules close to cell membrane
 ACTH, β-MSH, Met-enkefalin, endorfin
► β2 –
cells (Endocrinocytus thyrotropicus)
 Large cells, small granules by BM
 TSH
►δ
– cells (Endocrinocytus gonadotropicus)
 Large cells, middle size granules
 FSH, LH
electron microscope
Adenohypophysis
imunoperoxidase
modifikovaný
Azan
►
HE
reaction to LH
Pars tuberalis adenohypophysis
► surrounds
infundibulum
► Numerous capillaries
► mostly δ – cells
 Little bit β2 – cells
Pars intermedia adenohyophysis
► rudimentary
► Cells
compose celumns
► Bazophilic cells
► Could be present sac (Ratkhe´s folliculus)
Posterior lobe = Neurohypophysis
► Eminentia
mediana
 Bottom of IIIrd ventricle
 Numerous non-myelinated nerve fibers
► stalk
= Infundibulum
 Tractus hypothalamohypophysialis
 Neurofibra neurosecretoria (+ vesicula
neurosecretoria) – non myelinated nerve fibers)
►Some
► Lobus
terminate by capillaries
nervosus; Pars nervosa
Lobus nervosus / Pars nervosa
neurohypophysis
► Nerve
fibers
 Axons of neurons from hypotalamus
 Corpusculum neurosecretorium (Herring
corpuscles) – accumulation of granules
 oxytocin + ADH (antidiuretic hormone =
vasopressin)
► pituicytes
 Glial cells
► capillaries
(synapsis neurohaemalis)
Examination and diseases
► CT
► Levels
of hormones
► Tumors
of hypophysis – usually benign,
hormally active
► Sheehan syndrome – after delivery bleeding
into hypophysis
Thyroid gland
Glandula thyroidea
Thyroid gland – history
► Galén
– to water inside of pharynx
► Paracelsus – struma + cretenism
► Wharton
– to make neck more beautiful
► 1844 Simon – endocrine gland
► 1891 Murray – administration of extract from TG
► 1895 Baumann – TG contains iodine components
1614-1673
Thyroid gland - anatomy
► Glandula
thyroidea
► thyroxin
T4, trijodtyronin T3
► kalcitonin
► Located
at the level C6-C7
► 2 lobes – lobus dexter + sinister
► isthmus
(on 2nd-4th tracheal cartillage)
► capsula fibrosa – 2 sheets – stroma
► parenchyma + lobuli
Thyroid gland – arteries and veins
► A.
thyroidea superior (from a. carotis externa)
► A. thyroidea inferior (z truncus thyrocervicalis) –
crossing with n. laryngeus recurrens
► A. thyroidea ima Neubaueri (from arcus aortae) - 2
%
► Vv. thyroideae superiores et mediae Lichačeva
(into V. jugularis interna)
► Plexus thyroideus impar (into v. brachiocephalica
sinistra)
Thyroid gland - development
► Development
since 24th day
► Exagination of endoderm of primitive pharynx
► Relative and absolute descencus - ductus
thyroglossus
► foramen caecum
► gll. thyroideae accessoriae
► Lobes
► lobus
origin
pyramidalis
► ligamentum suspensorium gl. thyroideae /
musculus levator glandulae thyroideae (smooth)
Thyroid gland - development
Thyroid gland - histogenesis
► solid
endoderm formation
► Ingrowth of surrounding mezenchyme and
blood vessels
► Ingrowth of ultimobranchial corpuscles
► 10th week – separation of cells into groups
► Single layer epithelium around lumina
► 11th week – production of koloid
Thyroid gland - composition
► capsule
(capsula fibrosa)
► stroma - septum (septas between lobes)
► lobus  lobulus  folliculus
► follicles (50 - 900 μm)
 spherical
 Single layer epithelium of follicular cells
 contains colloidum (coloid) - thyroglobulin
cells (thyrocytus T)
► Parafollicular cells (thyrocytus C)
► Follicular
Follicular cells (Thyrocytus T)
► Spherical
nucleus
► numerous gER (bazally) and MIT
► Numerous lyzosomes
► thyroglobulin,
cleavage of T4 and T3
Synthesis of hormones of thyroid
gland
►
►
►
►
►
►
►
►
1. iodine pump using ATP recirculates
iodine from blood into colloid
2. and 3. synthesis of thyroglobulin and
peroxidase, deposition in one secretory
vesicle and its release into colloid by
exocytosis
4. iodination off thyroglobulin using
peroxidase in colloid and formation of
iodinethyroglobulin
Endocytosis of iodinethyroglobulin
5. fusion of primary lyzozome with this
vesicle
Proteolysis of iodinethyroglobulin into T3,
T4 and other fragments
Release of T3 and T4 into circulation
6. binding of transport plasmatic protein
Parafolicular cells (thyrocytus C)
► C-cells
► Located
between follicles (individually, also
goups)
► Bigger, lighter
► numerous gER as well as GA, MIT
► granules – spherical, dark
► Prooduction and accumulation of
kalcitonin
Follicles of thyroid
gland
Thyroid gland –
examination
► ultrasound
► Scintigraphy
with radioactive iodine 131
Thyroid gland – disease
► ultrasound
► scintigraphy
with radioactive iodine 131
► Less
then 10μg iodine per day  struma from lack
of iodine
► hypotyroidizmus
 kretenizmus (children) – screening in newborns
 Myxedema (adults)
 autoimmune – Hashimoto struma
► hypertytoidizmus
(tyreotoxicosis)
 autoimmune – exophtalmic struma = Graves-Basedow
disease
Parathyroid gland
Glandulae parathyroideae
Parathyroid gland - characteristic
► Gll.
►2
parathyroidea superior et inferior
pairs of small spheroid structures on the
posterior side of lobes of thyroid gland
► Individual branches from a. thyroidea
inferior
► Role in bone metabolism
► parathormon (PTH)
Parathyroid gland - development
► Dorsal
part of IIIrd and IVth branchial
exagination
► 5th week – proliferation of endoderm, loss
of lumen
► Ingrowth of vessels from mesenchyme
► Principal
cells – fetal metabolism of calcium
► Oxyphilic cells – origin in 7th year of life
Parathyroid gland - development
Parathyroid gland - composition
► capsule
+ septas
► parenchyme parcellated into columns
► Principal cells (parathyrocytus endocrinus)
 Relatively large (4-8 um)
 light cytoplasm
 Granules containing PTH
► Oxyphilic
cells (Parathyrocytus oxyphilicus)
 Rare, bigger
 cytoplazm darker, w/o granules, numerous MIT
 Function not clear
Parathyroid gland
disease
► hyperparatyroidizmus
 primary (adenoma)
►Patological
calcification of tissue (based on
hypercalcemia)
►Recklinghausen bony osteodystrofia (fractures)
►nephrolitiasis
 secondary (reactive hyperplazia PT in
hypocalcemia in kidney diseases)
 terciary (in case of successful kidney
transplantation)
Parathyroid gland - disease
► hypoparatyroidizmus
 tetany
 iatrogenic in case of tumor excision
►Transplantation
subcutaneously
► examination
of gland on the forearm
– nuclear medicine