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fenestrated epithelial cells

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mjl1717

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Jun 17, 2006 - 1:12 PM

which has fenestrated epithelial cells??

a)liver
b)kidney
c)colon
d)stomach
e)pancreas

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spjokes

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Jun 17, 2006 - 5:51 PM

B

Cells of the inner layer, podocytes in the visceral layer have small foot like processes (pedicles) of their cytoplasm forming a fenestrated epithelium around the fenestrated capillaries of the glomerulus.

robin082006

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Jun 17, 2006 - 7:08 PM

A. Liver

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Jun 17, 2006 - 8:12 PM

talkin about fenestrated capillaries..
fenestrations are >10 micron sized areas with no covering of basement membrane ...
they are in liver

in kidney there are PORES that are in the range of 2 micron size...
theydont allow the cells to pass through them...
and they are also lined by basement membrane...
grin

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Jun 17, 2006 - 8:12 PM

option A

Slacker

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Jun 17, 2006 - 8:51 PM

First look at the definition of Fenestrations--->they are holes inside the cells. Sinisouds are GAPS between cells(NOT HOLES in cells). So the kidneys have fenestrated cells(holes in cells). Liver has sinisouds(which are GAPS betweens cells). My reference is Dr. Goljan!!! grin

Slacker

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Jun 17, 2006 - 8:51 PM

Ans: B

mjl1717

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Jun 17, 2006 - 9:02 PM

liver is corrrect

Slacker

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Jun 18, 2006 - 12:38 AM

i checked on that and i guess u guyz r right. I didn't read the questions carefully. it is asking for fenestrated EPITHELIAL cells not ENDOTHELIAL cells. The Endothelial cells of the kidney are fenestrated. That was kinda of a picky question. But i still don't get how siniosoids are fenestrated... raised eyebrow

jedw

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Jun 18, 2006 - 3:25 AM

#10

so there's a mistake in the question

in the kidney there are FENESTRATED ENDOTHELIAL cells in the glomerulus, while in the liver there are sinusoids covered with ENDOTHELIAL cells between which GAPS (not fenestrations) are present.. the correct ans. is B

take care

jedw

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Jun 18, 2006 - 3:31 AM

#11

the kidney has also EPITHELIAL cells = podocytes, which form filtration slits with filtrqtion membranes, maybe u can call them "fenestrated", nevertheless the kidney seems the right option..

robin082006

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Jun 18, 2006 - 8:11 AM

#12

Jedw,

Liver is the only organ that has fenestrated epithelial cells (Kaplan)

Mj1717 created this question and has given the answer, did you see it?

vallia

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Jun 18, 2006 - 12:18 PM

#13

the question is not clear

we have fenestrated endothelium lining the sinusoids in the liver, no basement membrane , practically the hepatocytes are bathed in blood plasma.

and also the glomerular capillaries in the kidneys have an endothelium that is fenestrated (full of holes). But here the fenestrations are too small to allow blood cells through but plasma can pass freely.

please clarify

a nice histo site

http://www.siumed.edu/~dking2/erg/liver.htm

ts97

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Jun 19, 2006 - 6:01 AM

#14

courseweb.edteched.uottawa..../HistologyBloodVessels.htm
Capillaries are classified according to the structure of their endothelial cells.

Continuous capillaries (most capillaries) have a continuous endothelial cells with no fenestrations (openings) in their walls. They are found in nervous tissue, muscle tissue, lung, connective tissue and exocrine glands. a. Fenestrated capillaries have endothelial cells in which are found small openings, called fenestrae, of about 80- 100 nm in diameter. The fenestrations are covered by a small non-membranous diaphragm (which may be the remnant of the glycocalyx enclosed by pinocytotic vesicles from which the fenestrae may be formed). The basement membrane of endothelial cells is continuous over the fenestrae. Fenestrae allow greater permeability and the rapid passage of macromolecules smaller than plasma proteins. Fenestrated capillaries are found in the intestine and endocrine glands.
b. A special type of fenestrated capillary with no diaphragm is found in the renal glomerulus. This capillary has a thick basement membrane. Sinusoids, also called discontinuous capillaries, have a large lumen and follow a tortuous path. They have many fenestrations with no diaphragm , and a discontinuous or absent basal lamina. The lumen is lined with phagocytic cells. They are found in the liver, hematopoietic organs (bone marrow, spleen) and some endocrine organs.

ts97

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Jun 19, 2006 - 6:05 AM

#15

Sorry, should be like this:

Capillaries are classified according to the structure of their endothelial cells.

1. Continuous capillaries (most capillaries) have a continuous endothelial cells with no fenestrations (openings) in their walls. They are found in nervous tissue, muscle tissue, lung, connective tissue and exocrine glands.

2. Fenestrated capillaries have endothelial cells in which are found small openings, called fenestrae, of about 80- 100 nm in diameter. The fenestrations are covered by a small non-membranous diaphragm (which may be the remnant of the glycocalyx enclosed by pinocytotic vesicles from which the fenestrae may be formed). The basement membrane of endothelial cells is continuous over the fenestrae. Fenestrae allow greater permeability and the rapid passage of macromolecules smaller than plasma proteins. Fenestrated capillaries are found in the intestine and endocrine glands.
a. A special type of fenestrated capillary with no diaphragm is found in the renal glomerulus. This capillary has a thick basement membrane.

3. Sinusoids, also called discontinuous capillaries, have a large lumen and follow a tortuous path. They have many fenestrations with no diaphragm , and a discontinuous or absent basal lamina. The lumen is lined with phagocytic cells. They are found in the liver, hematopoietic organs (bone marrow, spleen) and some endocrine organs.

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Jun 19, 2006 - 8:13 AM

#16

thanks people smiling face