Anatomy and histology of endocrine organs L11 Flashcards
what does the gap between the first and second arch form on the outside
external auditory meatus
what lines all the way around the foetus and into the mouth
ectoderm
what line the gut tube
endoderm
what makes up the oropharyngeal membrane on the outside
ectoderm
what makes up the oropharyngeal membrane on the inside
endoderm
what happens on the roof of the mouth
some ectoderm is growing upwards to meet the central nervous system
what is happening on the undersurface of the neural tube
neural ectoderm is growing down to meet the growing mouth ectoderm
what is the ectoderm growing up through the roof of the mouth called
hypophysial diverticulum
in pharyngeal arches what does mesoderm form
mesoderm arch (in middle)
in pharyngeal arches what does ectoderm form
ectoderm groove on lateral (external) side
in pharyngeal arches what does endoderm form
endoderm pouch on medial (internal) side
what does the mesoderm core form (4)
cartilage
muscle
nerve
artery
which side of the pharyngeal arches mainly zips up to form a smooth surface
the ectoderm groove
what is the other name for the pituitary gland
hypophysis
how is the pituitary attached to the base of the skull
infundibulum (a stalk)
what is the pituitary in contact with
hypothalamus
what plane does the pituitary lie in
midline
where is the pituitary in relation to the optic chiasm
posterior
where does the pituitary gland sit
sella turcica
2 lobes of the pituitary
anterior and posterior
what is different about the 2 pituitary lobes (3)
Histology
function
embryonic origin
what id inferior to the pituitary gland
pharynx
what is the embryological origin of the anterior lobe
oral ectoderm from roof of mouth
what is the embryological origin of the posterior lobe
neuroectoderm of diencephalon
blood supply to pituitary gland (2)
superior hypophyseal artery
inferior hypophyseal artery
venous drainage of pituitary gland
cavernous sinus
where do axons release neurohormone in the anterior lobe of pituitary
primary plexus
where does the primary plexus link to
hypothalamo-hypophyseal portal system
overall role of anterior lobe
receives neurohormone via portal system which dictates what endocrine cells secrete
what is the posterior lobe made off
axons
what happens in the posterior lobe
axons terminate and release neurohormone directly into the blood system
histology of anterior lobe=
typical endocrine= cords of epithelial cells interspersed with capillaries
name 2 acidophillic anteiror lobe cells
somatotrophs
mammotrophs
name 2 basophillic anterior lobe cells
corticotrophs
thyrotrophs
gonadotrophs
histology of posterior lobe
mainly non-myelinated neurons
with pituicytes supporting cells
where is the thyroid gland
C5-T1 stuck on the trachea
what is the thyroid isthmus
midline where right and left lobes meet
where is the isthmus
cricoid level
what is the pyramidal lobe of the thyroid
variable bits of lobe coming off
what is the thyroid bound in
fascia
arterial supply to the thyroid
superior thyroid artery
inferior thyroid artery
where does the superior thyroid come off
external carotid
where does the inferior thyriod artery come from
subclavian–>thyrocervical trunk
venous drainage of the thyroid (3)
superior thyroid
middle thyroid
inferior thyroid
where do the superior thyroid and middle thyroid drain into
internal jugular vein
where does the inferior thyroid gland drain into
brachiocephalic vein
embryological origin of the thyroid
endoderm on the surface of the developing tongue which starts burrowing down
what is the name for the endoderm on the surface of the tongue which starts burrowing down
thyroid primordium
what is the foramen left behind on the tongue from the thyroid primordium
blind foramen —> foramen cecum of the tongue
what is the thyroid gland inferior to
the larynx
2 cells of thyroid
follicular cells
parafollicular cells
what do follicular cells surround
the follicles
what is stored in the follicles
secretory product
whats special about the thyroid
only endocrine gland to store product in great quantity
what do parafollicular cells do
secrete calcitonin
how many parathyroid glands
2 superior
2 inferior
what is the position of the parathyroid glands
very variable
blood supply of parathyroid glands
superior and inferior thyroid
2 cells of parathyroid gland
chief cells
oxyphil cells
which parathyroid cell is dominant
chief cells
what hormone do chief cells secrete
parathyroid hormone
what happens between the 1st and 2nd pouch where endoderm and ectoderm meet
form an eardrum (tympanic cavity)
what does the endoderm form between the 1/2 pouches
auditory tube
what does the endoderm form between 2/3
palatine tonsils
what does the endoderm form between 3/4
inferior parathyroid gland and the thymus
what forms underneath the 4th arch
superior parathyroid gland and parafollicular cells
