Endocrine Workbook Flashcards
What are the main endocrine organs of the body?
Thyroid gland, parathyroid gland, pituitary gland, adrenal gland, pancreas and testes
What is the name of the depression which the pituitary gland sits on?
Hypophysial fossa in sphenoid bone
How is the optic chiasm related to the pituitary gland?
Superior
What would be the resultant visual field defect due to pituitary gland enlargement?
Bitemporal hemianopia
What are the different parts of the pituitary gland?
Anterior lobe
Posterior lobe
Pars intermedia
Which lobe of the pituitary gland is larger?
Posterior lobe
Which of the lobe of the pituitary gland is glandular and manufactures numerous hormones?
Anterior
What is the function of the posterior lobe of the pituitary gland?
Posterior stores
Secretes oxytocin and ADH
How does the anterior and posterior lobes of the pituitary gland look like on H&E stain?
Anterior is dark staining
Posterior is pale staining
What lobe of the pituitary is this image of?
Anterior
Under high power
What are the 3 cell types in anterior pituitary histology?
Acidophilic - stain pink
Basophilic - stain light purple
Chromophobic - appear pale and don’t take up much stain
What lobe of the pituitary gland is shown?
Posterior
What does the histology of the posterior lobe show?
Non-myelinated axons which are neurosecretory axons
Cell bodies of these are located in hypothalamus
What are the 2 classes of acidophils?
Somatotrophs
Mammotrophs
What is the target organ and secretory product of somatotrophs?
GH
General but main is chondrocytes
What is the secretory product and target organ of mammotrophs?
Prolactin
Milk producing tissue
What are the 3 classes of basophils?
Corticotrophs
Thyrotrophs
Gonadotrophs
What is the secretory product and target organ of corticotrophs?
ACTH - corticosteroids of adrenal cortex
MSH - melanocytes
What is the secretory product and target organ of thyrotrophs?
TSH
Follicular epithelial cells
What is the secretory product and target organ of gonadotrophs?
FSH - follicular cells of ovaries or sertoli cells of testes
LH - developing follicles
What is the arterial blood supply for the pituitary gland?
Internal carotid gland - superior hypophysial artery and inferior hypophysial artery
What artery supplies the anterior lobe of the pituitary gland?
Superior hypophysial artery
Enters substance of hypothalamus before breaking up into capillaries - creating hypophysial portal system
What artery supplies the posterior lobe of the pituitary gland?
Inferior hypophysial artery
How does the hypothalamus communicate with the anterior pituitary?
Capillary portal system
Hormones are released from neurosecretory neurons at median eminence
How does the hypothalamus communicate with the posterior pituitary gland?
Hormone packed in cell body then transported down cell
Vesicles containing hormone in posterior pituitary - released into blood
Axons and nerve terminals
Where is the thyroid gland located?
Anterior to trachea and inferior to the larynx
C5 to T1 and between cartilage and 6th tracheal ring
Where does the isthmus lie oppisite?
2nd and 3rd tracheal rings
Which strap muscles overlie the thyroid gland?
Sternohyoid and sternothyroid
What are the 2 nerves which supply the muscles of the vocal cords?
Recurrent laryngeal and superior laryngeal nerves
What is the location of the recurrent and superior laryngeal nerves in relation to thyroid gland?
Recurrent - runs between trachea and oesophagus
Superior - between thyroid cartilage and hyoid bone
From which major artery in the neck does the superior thyroid artery arise?
External carotid artery
From which artery does the inferior artery arise?
Subclavian artery
Which vein does the superior and middle thyroid vein drain into?
Internal jugular vein
Which vein does the inferior thyroid vein drain into?
Brachiocephalic vein
Describe the histology of the thyroid gland
Hormones of thyroid gland are stored in cavities and surrounded by secretory cells
These make up a follicle
Within the follicle - the hormone is bound to a glycoprotein and called a colloid
What is A, B, C and D?
A - colloid
B - follicular cells
C - follicle
D - parafollicular cells/ clear cells
What colour does the colloid stain?
Pink
What hormones does the thyroid gland secrete?
T3 and T4
Calcitonin
Where are the parathyroid glands located?
Lie on medial half of the posterior surface of each thyroid lobe, external to the thyroid fibrous capsule
Where are the superior parathyroids situated?
Level of inferior border of the cricoid cartilage
Where are the inferior parathyroids situated?
Near the inferior poles of the thyroid, though position is variable
Describe the arterial blood supply of both superior and inferior parathyroid glands
Predominantly from inferior thyroid arteries
Describe the venous drainage of the superior and inferior parathyroid glands
Veins draining the thyroid to the internal jugular veins
What are the 2 cell types present in the parathyroid glands?
Chief cells - more numerous and have darker staining cytoplasm
Oxyphil cells
What hormone does the parathyroid gland secrete and its function?
PTH
Regulation of Ca levels in the blood
What cells does PTH act upon and what is the action?
Osteoclasts - reabsorption of bone which releases Ca
Intestinal cells - indirectly causes an increase in the activity of the enzyme which activates Vit D which promotes Ca absorption from intestines
Kidney cells - decreases urinary excretion of Ca and increases K excretion
How are the adrenal glands peritonised?
Retroperitoneal
What are the 2 parts of the suprarenal glands?
Outer cortex and inner medulla
What are the embryological origins of the cortex and medulla of the suprarenal gland?
Cortex - mesodermal epithelium
Medulla - neuroectoderm
Describe the blood supply of the suprarenal glands
Arise from inferior phrenic arteries (superior), aorta (middle) and renal arteries (inferior suprarenal artery)
Describe the venous drainage of the suprarenal glands
One suprarenal vein
On right side drains into IVC
On left side drain into left renal vein
What are the 3 distinct zones of the cortex?
Outer zona glomerulosa
Middle zona fasciculata
Inner zona reticularis
What does the medulla of the suprarenal glands secrete?
Large ovoid chromaffin cells secrete adrenaline and noradrenaline
What are the main 3 hormones secreted by the 3 zones of the cortex?
G - aldosterone
F - Glucocorticoids
R - sex hormones
Is the pancreas intra or retro peritoneal?
Pancreas head and body - retro
Tail - intra
What are the parts of the pancreas?
Head, Neck, Body, Tail and Uncinate process
What is the level of the transpyloric plane?
L1
What arteries supply the pancraes?
Inferior pancreaticoduodenal artery
Gastroduodenal artery
Splenic artery
Superior mesenteric artery
What cell types are found in the islets of Langerhans and what do they secrete?
Alpha - glucagon
Beta - insulin
Delta - somatostatin
P - pancreatic polypeptide
