Lab 1 - Pancreas and adrenal glands Flashcards
Which germ layer is the adrenal cortex derived from
Mesoderm (primitive mesothelium)
Which germ layer is the adrenal medulla derived from
Ectoderm (neural crest-primitive autonomic ganglion tissue)
What tissue makes up the adrenal capsule?
Fibrous connective tissue
What tissue is found outside the capsule of the adrenal gland?
loose connective tissue containing white fat (unilocular adipose tissue)
What is the anatomical name of the tissue surrounding the adrenal capsule
Perinephric fat
Describe the histology of the zona fasciculata
radially orientated columns of cells, 2-3 cells wide, separated from neighbouring columns by radially orientated, straight blood vessels.
Describe the cells of the zona glomerulosa
Between the fibrous capsule and the zona fasciculate occur groups
of a few columnar cells arranged to form an arch or part of a ball.
Describe the difference in staining between cells of the zona fasciculata and the zona glomerulosa
ZG cells stain more darkly with small dark granules in their cytoplasm
What is the alternative name for cells in the zona fasciculate and describe their histology
Spongiocytes
- appear pale in an H&E stained section and contain
empty looking, small rounded profiles as lipid and cholesteral has been removed during processing
Describe the blood vessels found in the cortex of the adrenal gland
fenestrated capillaries
What is the approximate size of RBC?
7μm
Describe the organisation of the zona reticularis
The secretory cells form a three dimensional network
Describe the histology of the medulla
rounded cords of large cells stained a brownish purple colour in an H&E stained section
Describe the blood flow in the adrenal medulla
The suprarenal medulla receives blood first from the capillaries and sinusoids of the suprarenal cortex,
second from arterioles passing from the capsule to the medulla.
What cells surround the blood vessels in the adrenal medulla?
secretory cells
What do the secretory cells in the adrenal medulla contain?
epinephrine and norepinephrine secretory granules
Describe the glandular classification of the pancreas
mixed endocrine and exocrine
What are the distinct histological features of islet of Langerhans?
The epithelial secretory cells form small groups or islets within the exocrine pancreas
How are islets of Langerhans formed?
by irregular, anastomosing rows or plates of cells separated by tortuous blood
capillaries
Which cell within the islet of Langerhans stain blue with Alcian blue and H
The β cell (insulin secreting cell)
Which cell within the islet of Langerhans stain redwith Alcian blue and H
The α cell (glucagon secreting cell)
What do δ cells secrete?
somatostatin
What do PP cells secrete?
pancreatic polypeptide
Describe the blood supply to and from the islets of Langerhans
An arteriole enters one side of the islet and gives rise to a number of capillary branches passing through the Islet (fenestrated capillaries), which, with high content of endocrine hormones in their blood, pass into the exocrine pancreas.
Which type of blood vessel passes through an Islet of
Langerhans?
capillaries or small venules
What can you say about the relative concentration of hormones within the blood entering the post-Islet exocrine pancreas?
The conc. of insulin and glucagon is high
proportion of each vary with blood glucose content
Does the high conc. of insulin influence activity of other
biomechanisms apart from uptake of glucose?
Yes
increased production of insulin by beta cells in the islets stimulates/upregulates synthesis of exocrine pancreatic digestive enzymes for release into the duodenum via the pancreatic duct
