Exocrine and Specialised

Question 1

Where can the parotid glands be found?

Answer 1

By the side of the mouth and in front of the ears.

Question 2

What does the parotid glands secrete?

Answer 2

Mainly saliva, however it only constitute 40% of saliva secreted in total.

Question 3

How does the parotid glands differ to the other salivary glands?

Answer 3

They ONLY have serous glands, but also some adipose tissue.

Question 4

What is the parotid glands function?

Answer 4

To secrete a serous secretion that contains enzymes that digest food and lubricates the bolus during swallowing.

Question 5

Why is parotitis so painful?

Answer 5

Because the parotid glands are enclosed in a tough fibrous capsule. So when swelling occurs the amount is limited so it pushes on the capsule and makes the swelling very painful.

Question 6

What is the stimulation of the parotid glands?

Answer 6

Parasympathetic in order to increase saliva production.

Question 7

Where can you find the sublingual gland?

Answer 7

Below the tongue

Question 8

How do the parotid glands and the sublingual gland differ?

Answer 8

Where the parotid gland is only made of serous glands the sublingual gland is almost completely mucous with numerous of demilunes.

Question 9

Where can you find the submandibular glands?

Answer 9

Below the sublingual gland and the parotid glands.

Question 10

How do the submandibular glands differ from the other two salivary glands?

Answer 10

The submandibular glands are made of mostly serous glands but also some mucous glands.

Question 11

What is the stimulation of the salivary glands?

Answer 11

Parasympathetic to produce a water saliva rich in enzymes (serous)
Sympathetic to produce a small, thick secretion of saliva rich in mucus (mucous)
The control of salivary secretion is neural only.

Question 12

Which is the largest exocrine gland in the body?

Answer 12

The liver.

Question 13

What are hepatocytes?

Answer 13

Liver cells.

Question 14

What is a sinusoid?

Answer 14

An irregularly shaped tube through which blood passes. However it is not a blood vessel. Can also be found in spleen and bone marrow. It has large gaps between the cells it consist of.

Question 15

What are the three types of vessels?

Answer 15

Continuous
Fenestrated
Sinusoid

Question 16

What two vessels come together in a liver acinus, what do they merge into and where do they end up?

Answer 16

The hepatic portal vein and the hepatic artery merge into a sinusoid and end up in the central vein.

Question 17

What is a liver lobule?

Answer 17

A hexagonal shaped (6 sided) structure clearly seen in histology. It usually consist of 6 portal triad and consist of one single central vein.

Question 18

What does a portal triad consist of?

Answer 18

1 hepatic artery
1 hepatic portal vein
1 bile duct

Question 19

What are pit cells?

Answer 19

Most active form of natural killer cells. They kill tumour cells that enter the sinusoids.

Question 20

What are kupffer cells?

Answer 20

Specialist macrophages that form part of the sinusoidal lining.

Question 21

Can you find kupffer cells anywhere else in the body?

Answer 21

Yes, kupffer cells constitute 80% of the tissue macrophages present in the body.

Question 22

What are the main roles of Kupffer cells?

Answer 22

To remove cell debris, bacterial endotoxins.

but especially trap phagocytose and any damaged or aged erythrocytes that were missed by the spleen.

Question 23

How do the Kupffer cells in the liver relate to a splenectomy?

Answer 23

After a splenectomy the kupffer cells in the liver take over the removal of 120 day old (aged) erythrocytes.

Question 24

What are stellate (Ito) cells?

Answer 24

They are full of cytoplasmic vacuoles containing vitamin A.

Question 25

What happens to Ito cells during liver cirrhosis?

Answer 25

The hepatic Ito cells lose their vitamin A storage capability. This causes them to differentiate into myofibroblasts and therefore they start to lay down collagen within the perisinusoidal spaces resulting in liver fibrosis.

Question 26

What are the main functions of the liver?

Answer 26

Storage
Anabolism (production)
Catabolism (destruction)
Bile production
Filtering of cell debris
Hormone production

Question 27

What does the liver store?

Answer 27

Iron
Vitamin A, B12, D and K (Lipid soluble vitamins)
Glycogen
Copper

Question 28

What does the liver produce?

Answer 28

More than 60% of all the body's proteins:
Albumin
Enzymes
Lipid carrier proteins
Amino acid synthesis
Haemopoeisis in fetus
Also hormones and growth factors

Question 29

What does the liver destroy?

Answer 29

Drugs
Hormones (Insulin, glucagon, steroids etc…)
Haemoglobin (bilirubin passed to gall bladder)
Poisins and toxins
After splenectomy RBCs

Question 30

How do hepatocytes differ to other cells?

Answer 30

They have a lot of mitochondria.
Lots of peroxisomes
Lots of free ribosomes
Lots of rER
Lots of see
Lots of Golgi

Question 31

How does the liver differ to the pancreas in terms of endocrine and exocrine functions?

Answer 31

In the pancreas the same cells do not work as endocrine and exocrine.
In the liver the same cells work as endocrine and exocrine (hepatocytes).