anatomy and histology of endocrine system Flashcards
What is the overall structure of endocrine glands
The functional unit is made up of cuboidal secretory cells with a lumen at the centre
secretory cells supported by myoepithelial cells
not all endocrine functional units have a lumen e.g. pituitary and parathyroid glands
What are some clinical manifestations of endocrine diseases
Hormone over/under production
tumour/ mass lesion which can be :
- non functional—> pressure effect
- associated with the overproduction of hormones
What are the 2 lobes of the pituitary gland
Adenohypophysis/ anterior lobe
neurohypophysis/ posterior lobe
name the cells of the adenohypophysis that take up stains and its staining pattern
Acidophils- takes up acidic dyes
basophils- takes up basic dyes
chromophobe- no specific staining features
name cells from the adenohypophysis
somatotroph, lactotroph, corticotroph, gonadotroph and thydrotrophs
What hormone do somatotrophs make and what is its target organ
Growth hormone and the target is bones
What hormone does lactotroph make and what is its target organ
prolactin and the target is breasts
What hormone does gonadotroph make and what is its target organ
FSH, LH and the target is ovaries and testes
What hormone do corticotrophs make and what is its target organ
ACTH and the target is adrenal glands
What hormone do thydrotrophs make and what is its target organ
TSH and the target is the thyroid gland
What are 2 hormones that are made in the neurohypophysis
ADH and Oxytocin
What are 2 hormones that the thyroid gland makes
T4- thyroxine, T3- triiodothyronine
both of these stimulate metabolic rate
synthesis of both of these requires iodine, lack of iodine can lead to an enlarged thyroid gland (goitre), this is done to absorb max concentration of iodine.
What are the chemical classifications of hormones
Steroid- e.g. testosterone
protein/ peptide- e.g. ADH, Oxytocin, insulin
amine- e.g. adrenaline, dopamine etc
The hypophysis is suspended under the hypothalamus by what, where is the hypophysis located
by the infundibulum, located in the sella turcica
Outline the blood supply to the hypophysis
2 vessels, branches of the int carotid
superior hypophyseal, supplies median eminence, the upper part of the infundibulum
inferior hypophyseal, supplies neurohypophysis, the lower part of the infundibulum
Describe venous drainage in the hypophysis
Capillary plexuses in median eminence and infundibulum ending are drained by portal veins which pass to the adenohypophysis, the veins form a secondary cap plexus.
Describe the structure of the thyroid gland, what controls it and its role
2 lobes, connected by an isthmus that courses anterior to the trachea, under control from hypothalamus and hypophysis,
the role in regulating tissue metabolism, growth and development
What is the arterial supply to the thyroid
Superior thyroid artery (from external carotid) and inferior thyroid artery (from subclavian)
What is the venous drainage of the thyroid
from an extensive plexus into the internal jugular vein and brachiocephalic vein.
What are the parathyroid glands
4 parathyroid glands, 2 sup and 2 inf embedded in the capsule of the thyroid, posterior aspect on either side.
very small.
What is the role of the parathyroid gland
secrete a parathyroid hormone which regulated calcium and phosphate level within homeostasis.
must be preserved during thyroidectomy, if removed then calcium levels fall, muscles, inc resp and laryngeal, go into tetanic contraction—-> death.
Parathyroid hormone- VAN?
Vein: sup + med + inf thyroid
artery: primarily inf thyroid (also sup)
Nerve: from middle and inferior cervical ganglions
What are the adrenal glands
Suprarenal glands, release hormones in response to stress, they are retroperitoneal.
capsule- secretes mineralcorticoids e.g. aldosterone
cortex- secretes adrenal androgens e.g. testosterone
deeper cortex- secretes glucocorticoids e.g. hydrocortisone.
adrenal glands- blood supply and venous drainage
blood supplied by sup (inferior phrenic)
middle (from the aorta)
inferior suprarenal artery (renal)
venous drainage- adrenal veins which drain into IVC or renal veins
