Why is the pancreas described as both an exocrine and an endocrine gland?

Its acinar tissue secretes digestive enzymes into a duct leading to the duodenum, which is exocrine secretion, while its Islets of Langerhans secrete hormones directly into the blood, which is endocrine secretion.

What is the exocrine tissue of the pancreas called, and what does it secrete?

It is called acinar tissue, and it secretes pancreatic juice containing digestive enzymes such as amylase, proteases and lipase.

How can the Islets of Langerhans be recognised in a stained photomicrograph of pancreas?

They appear as roughly spherical, pale-stained clusters of cells scattered among the much darker-stained acinar tissue.

OCR A-Level Biology B H422

The Developing Cell: Cell Division and Cell Differentiation

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The Hormonal Control of Blood Glucose and the Management of Diabetes

Topic overview The pancreas as an endocrine gland The regulation of blood glucose by negative feedback Types of diabetes and diagnostic testing Treating and managing diabetes

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The Hormonal Control of Blood Glucose and the Management of Diabetes

The pancreas as an endocrine gland

3 things to know
Components 01, 02 and 03

Overview

Recall questions on the gland's dual role, telling islet from acinar tissue in a stained section, the organelles abundant in a beta cell, graticule calibration, and magnification calculations.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Evaluation

Give one advantage and one disadvantage of using an electron micrograph rather than a photomicrograph to study pancreatic tissue.

Key term

Name the two hormones secreted by the Islets of Langerhans and the cells that produce each.

Key term

Why does the acinar tissue of the pancreas take up stain more heavily than an islet does?

Questions from this subtopic

Each one with the model answer underneath.

1
Why is the pancreas described as both an exocrine and an endocrine gland?
Model answer
Its acinar tissue secretes digestive enzymes into a duct leading to the duodenum, which is exocrine secretion, while its Islets of Langerhans secrete hormones directly into the blood, which is endocrine secretion.
2
Name the two hormones secreted by the Islets of Langerhans and the cells that produce each.
Model answer
Insulin, produced by the β cells, and glucagon, produced by the α cells.
3
What is the exocrine tissue of the pancreas called, and what does it secrete?
Model answer
It is called acinar tissue, and it secretes pancreatic juice containing digestive enzymes such as amylase, proteases and lipase.
4
How can the Islets of Langerhans be recognised in a stained photomicrograph of pancreas?
Model answer
They appear as roughly spherical, pale-stained clusters of cells scattered among the much darker-stained acinar tissue.
5
Why does the acinar tissue of the pancreas take up stain more heavily than an islet does?
Model answer
Acinar cells are packed with rough endoplasmic reticulum and with granules of digestive enzyme, and these structures bind a great deal of stain.
6
Approximately what proportion of the mass of the pancreas is made up of the Islets of Langerhans?
Model answer
Only about 1 to 2 per cent.

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The pancreas as an endocrine gland

Overview

What you need to know

Give one advantage and one disadvantage of using an electron micrograph rather than a photomicrograph to study pancreatic tissue.

Name the two hormones secreted by the Islets of Langerhans and the cells that produce each.

Why does the acinar tissue of the pancreas take up stain more heavily than an islet does?

Questions from this subtopic

Why is the pancreas described as both an exocrine and an endocrine gland?

Name the two hormones secreted by the Islets of Langerhans and the cells that produce each.

What is the exocrine tissue of the pancreas called, and what does it secrete?

How can the Islets of Langerhans be recognised in a stained photomicrograph of pancreas?

Why does the acinar tissue of the pancreas take up stain more heavily than an islet does?

Approximately what proportion of the mass of the pancreas is made up of the Islets of Langerhans?

Other ways to work this

What is inside Levo

See a huge jump in your memorisation

Cram a whole paper in one sitting

Blank Blitz consolidates the facts

Build It trains answer structure

Test It catches misconceptions

Brain Breaks between sessions

Every question in The Hormonal Control of Blood Glucose and the Management of Diabetes, on a schedule.