T1 L3 p1 :The Nuts and Bolts of the Endocrine System: Anatomy and Histology Roadshow Flashcards
Go over anatomy pics in slide
what is the composition of a system
its a system of hormone secreting glands
what is the hypothalamus
the major controlling centre of the ANS
what does the hypothalamus regulate
temperature
circadian rhythms
Hunger
what are the properties of endocrine glands (3m)
they are ductless
highly vascularised
travel via interstitial space-blood or lymph
what is another name for the pituitary gland
the hypophysis
describe the anatomy of the hypophysis (2m)
what is it suspended by and where is it located
its suspended by the infundibulum, located in the sella turcica
what are the 2 structures that the hypophysis is split into (4m)
(science names and their type of part and growth from which part of the brain)
Adenohypophysis – glandular part; outpouching of ectoderm of oral cavity (fsh,lh,tsh)
Neurohypophysis – neural part; downgrowth from diencephalon of brain
(oxytocin,ldh)
what is the blood supply to the hypophysis
Superior hypophyseal, supplies
median eminence
upper part of stalk
Inferior hypophyseal, supplies
neurohypophysis
lower part of stalk
what signals are responsible for hormone release from the adenohypophysis and the neurohypophysis
Signals from the hypothalamus
describe the anatomy of the thyroid gland (5m)
structure, location, what embryological part and a bit about function
Bilobed gland in the neck
They are connected anterior to the trachea
From oblique line of cartilage to 5/6 tracheal ring
From endoderm
Controlled by hypothalamus and hypophysis
Via T3 and T4 it regulates tissue metabolism growth and development
what is the arterial supply to the thyroid gland
the super thyroid- from the ext carotid
inferior thyroid -from the subclavian
what is the venule drainage of the thyroid
from ext plexus into :
the int jugular vein
&
The braciocephalic vein
what are the structures contained in the thyroid gland
Cricothyrotomy
Recurrent nerve (from vagus)
what is the anatomy of the parathyroid gland
there are 4, each to the side of the thyroid gland :
2 superior and 2 inferior embedded in the posterior aspect of the capsule of the thyroid
what is the role of the parathyroid hormone
it regulates calcium and phosphate levels within homeostasis
why must the parathyroids be reserved during thyroidectomy
If removed, calcium levels can fall, which means that muscles such as heart and those for resp go into tetanic contraction, leading to death
what is the arterial and venule supply to the parathyroids
arterial - sup thyroid-ext carotid and inf thyroid-subclavian
vein: sup middle and inf thyroid
innervation of the parathyroids
middle and inf cervical ganglions
what is the role of the adrenal glands
Vital as a stress response
Anatomy of the adrenal glands
At t12
retroperitoneal
the right is pyramidal and the left is semilunar
the cortex is derived from the mesoderm
the medulla is derived from the neural crest
what is the function of the cortex of the adrenal glands
Releases corticosteroids
1)Cells subjacent to the capsule secrete minealocorticoids- aldosterone
Function to maintain electrolyte balance-sodium
2)Deeper part of the cortex
Secrete glucocorticoids -hydrocortisone affectisone affect metabolism and electrolyte balance
3)also produces adrenal androgens-testosterone
what are the cells of the medulla
Chromaffin cells- secretory cells of the medulla, develop from embryonic tissue
what is the adrenal medulla associated with
The medulla is regarded as a modified sympathetic ganglion (ANS)
what does the adrenal medulla secrete
Medulla cells secrete adrenaline and smaller amounts of noradrenaline – i.e. catecholamines
what response is the adrenal medulla responsible for
‘fight-or-flight’ response: affects heart rate, blood pressure and smooth muscle of viscera
what is the blood supply for the adrenal medulla
supplied by the superior -(phrenic)
Middle- (aortic)
Inferior suprarenal arteries-(from renal)
what do the rami supply
the cortex and the medulla as they branch before entering the capsule
what do the cortical arteries give rise to
the subcapsular plexus
what do the subcapsular plexus distribute too
Cortical cells
what do the medullary arteries supply
the medulla - which also receives blood from the suprarenal arteries
what cortical hormones influence the medulla and how
cortisol mediates NA conversion to adrenaline
venous drainage of the adrenal gland
the adrenal veins - which drain into the IVC(r)
or the renal vein
(L)
what is ACTH
adrenocorticotrophic hormone
where is ACTH released and what is its function
The hypothalamus releases corticotrophin releasing hormone which causes the release of ACTH from the pituitary , which stimulates cortisol release
what else controls the adrenal gland activity
Symp division of ANS: coeliac plexus; splanchnic n
postganglionic fibres supply blood vessels
preganglionic fibres ramify around cells of the medulla
how does the ANS modulate the medulla
Has a fast response by impulses from preganglionic fibres that end in the chromaffin cells of the medulla.
they then release catecholamines into adjacent circulation
