Lab Two

Question 1

what is the role of acinar cells (exocrine function) in the pancreas?

Answer 1

To secrete digestive enzymes into the gastrointestinal tract

Question 2

what organelles are present in the acinar cells of the pancreas that support their exocrine function?

Answer 2

Need to synthesis lots of proteins
Rough endoplasmic reticulum and the golgi body
Many zymogen granules at the apical region of the cell

Question 3

how is DNA and RNA distributed in pancreatic acinar cells?

Answer 3

DNA is only present in the nucleus
RNA is present in the nucleolus and is free ribosomes and polyribosomes and rough endoplasmic reticulum

Question 4

how does the Methyl green- pyronin-Y stain the pancreas?

Answer 4

The nucleus is stained blue/green due to DNA (methyl green) and the nucleolus is stained pink due to RNA (pyronin-Y).
Pinking staining around the nucleolus due to mRNA

Pink staining in the cytoplasm due to free ribosomes and RER containing RNA

The zymogen granules do not stain and so this leaves a clear region at the cells apical region.

Question 5

how does toluidine blue stain mitochondria?

Answer 5

blue-grey

Question 6

how does toluidine blue stain zymogen granules?

Answer 6

dark blue

Question 7

where are zymogen granules located in acinar cells?

Answer 7

On the apical region, these cells are secretory and the zymogens contain the secreted proteins that have been synthesized within the cell.

Question 8

where is amylase located within the pancreatic cell?

Answer 8

It would be located throughout the secretory pathway.
Through the RER, golgi apparatus, zymogen granules and also the lumen of the acinus

Question 9

why is there so much RER in the pancreatic cells?

Answer 9

The pancreatic cells need to synthesize large amounts of proteins

Question 10

what is the endocrine role of the pancreas?

Answer 10

Secreting insulin and glucagon into the blood stream

Question 11

what are the features of simple squamouse epithelia within the pancreas?

Answer 11

Flattened soma, squashed but bulging nucleus, lining a blood vessel

Question 12

what are some features of cuboidal eopithelia in the pancreas?

Answer 12

Square-shaped cell, centrally placed nucleus, lining a duct

Question 13

what type of junctions are found in the epithelia lining the blood vessels within the pancreas?

Answer 13

Tight junctions, to prevent the unwanted transfer of substances to and from the lumen of the vessel and between cells

Question 14

what are the type of junctions found in the simple cuboidal epithelia of the pancreas?

Answer 14

Tight junctions apically to prevent the backflow of secretions between cells.

Junctional complexes to allow for parallel connections between adjacent cells (T, A, D junctions)

Question 15

what is the function of microvilli and where are they found?

Answer 15

increase the surface area for absorption/secretion.
Found in the small intestine, and in the nephron

Question 16

what is the function of cilia and where are they found?

Answer 16

move substances on apical surface. Found in the respiratory tract and the reproductive system

Question 17

what is the structure of microvilli?

Answer 17

Microvilli are fingerlike extensions of the plasma membrane about 0.5-1 micrometer in length. The cytoplasmic core contains parallel bundles of actin microfilaments which insert into the terminal web of the cytoskeleton and is anchored peripherally to zonula adherens.

Question 18

what is the structure of cilia?

Answer 18

Cilia can be motile or non motile

Cilia can be up to 10 micrometers in length
Cilium is surrounded by a plasma membrane and contains a central core called the axoneme.

The axoneme contains 20 microtubules arranged with one central doublet and 9 peripheral doublets. These are linked by proteins called nexin

Each microtubule has arms made of the protein dynein, which catalyzes the conversion of ATP to ADP which causes the doublets to bend and create the cilia wavelike motion.

Question 19

what is the function of non-motile cilia?

Answer 19

for sensory information

Question 20

what is the function of motile cilia?

Answer 20

to beat in a wave-like pattern to move substances from the surface of the cell

Question 21

how can you distinguish microvilli and cilia?

Answer 21

Different structure visible under electron microscopy
Size relative to the cell

Question 22

where in the body are both microvilli and cilia found and why?

Answer 22

In the pseudostratified ciliated columnar epithelium found in the respiratory tract

The cilia move luminal contents

The microvilli increase the surface area for secretion

Question 23

what epithelium are cilia found on?

Answer 23

only pseudostratified epithelium

Question 24

why does the trachea contain pseudostratified ciliated epithelium?

Answer 24

The cilia beat mucosal secretions toward to pharynx (to be coughed out or swallowed)

Question 25

why does the oesophagus contain stratified epithelium?

Answer 25

has multiple layers of flattened epithelia that can be sloughed off without damaging the underlying tissue with the abrasive force of swallowing and food passing down the tube.

Question 26

what is the role of islets of Langerhans in the pancreas?

Answer 26

produce insulin