S4 Exocrine Tissue

Question 1

Describe the differences in number of mucous and serous glands in parotid, submandibular and sublingual glands.

Answer 1

Parotid - mostly serous

Submandibular - serous and mucous

Sublingual - mostly mucous

Question 2

What is the structure of ducts in the parotid glands?

Answer 2

Striated, simple columnar epithelium with a large lumen

Question 3

What are the two parts of the submandibular gland and what are they separated by?

Answer 3

Superficial and deep

Separated by the mylohyoid muscle

Question 4

What does parasympathetic and sympathetic stimulation mean for the salivary glands?

Answer 4

Parasympathetic - leads to a large volume of watery saliva, rich in enzymes, produced

Sympathetic - leads to a small, thick secretion of saliva, rich in mucous, produced

Question 5

What is the largest exocrine gland?

Answer 5

The liver

Question 6

Is the liver regenerative?

Answer 6

Yes

Question 7

What are the two blood supplies to the liver (hepatic system)?

Answer 7

1. Hepatic portal vein (arterial blood —> stomach and intestine to the liver —> venous blood)
2. Hepatic artery (aorta —> liver)

Question 8

Does oxygenated or deoxygenated blood travel through the portal vein?

Answer 8

Deoxygenated

Question 9

Does oxygenated or deoxygenated blood travel through the hepatic artery?

Answer 9

Oxygenated

Question 10

Where can you find sinusoids?

Answer 10

Liver, spleen, bone marrow and lymph nodes

Question 11

Where do you find fenestrated capillaries? And why?

Answer 11

Pituitary, small intestine, kidneys and some endocrine glands

To allow fluid/small molecules to cross capillary epithelium quickly

Question 12

Where do you find continuous capillaries?

Answer 12

The brain and most of the body

Question 13

What is the shape of a liver lobule?

Answer 13

Hexagonal

Question 14

What colour does a liver lobule show up as when stained with H&E? And why?

Answer 14

Red (eosin stains proteins, implies lots of protein present)

Question 15

How many nuclei can hepatocytes have? And why?

Answer 15

1, 2 or 3

As they make lots of proteins so need to make lots of mRNA

Question 16

What fat is present in the liver?

Answer 16

Triglycerides and cholesterol (not adipose)

Question 17

What is the central vein in a liver lobule?

Answer 17

The hepatic venule

Question 18

What vessels make up the portal triad?

Answer 18

1. Portal vein
2. Bile duct
3. Hepatic artery

Question 19

What is a liver acinus?

Answer 19

The functional unit of the liver

Question 20

How does blood travel through a liver acinus?

Answer 20

Enters via the hepatic artery and portal vein and then travels through sinusoids to the hepatic venule

Question 21

What are pit cells? What do they do?

Answer 21

NK cells attached to the epithelial cells that kill tumour cells that enter the sinusoids

Question 22

Where do specialisations on epithelial cells sit in hepatocytes?

Answer 22

On the basolateral surface

Question 23

What is the space of Disse?

Answer 23

A serum-like fluid between the hepatocytes and sinusoids it contains the blood plasma. The microvilli of the hepatocytes extend into the fluid to absorb any proteins, etc from the sinusoids

Question 24

What support cells are present in the liver acinus?

Answer 24

1. Kupffer cells
2. Stellate/Ito cells
3. Dendritic cells
4. Pit cells

Question 25

What is the bile canaliculus?

Answer 25

Bile capillary that collect bile secreted by the hepatocytes and takes it to the bile duct

Question 26

What connections (junctions) are between hepatocytes?

Answer 26

Tight and gap junctions

Question 27

Where does the bile canaliculus go?

Answer 27

Between hepatocytes

Question 28

What are Kupffer cells? Where are they found? What do they do?

Answer 28

Specialised macrophages that are part of the sinusoidal lining Trap and phagocytose damaged/aged erythrocytes (missed by the spleen)

Question 29

If someone has a splenectomy, what do Kupffer cells take over the removal of?

Answer 29

(120 day old) aged erythrocytes

Question 30

What do stellate/Ito cells contain?

Answer 30

Full of cytoplasmic vacuoles that contain vitamin A

Question 31

What happens in liver cirrhosis?

Answer 31

Hepatic stellate cells lose their vitamin A storage capability and they differentiate into myofibroblasts

Question 32

What is the role of myofibroblasts in the liver?

Answer 32

Cells that synthesise and deposit collagen into the space of disse - leads to liver fibrosis

Question 33

What are the functions of the liver?

Answer 33

1. Storage 2. Anabolism 3. Catabolism 4. Bile production 5. Filtration

Question 34

What does the liver store?

Answer 34

Iron, lipid soluble vitamins (ADEK), glycogen and copper

Question 35

What does the liver catabolise?

Answer 35

Drugs, hormones, Hb, toxins and aged RBCs

Question 36

What does the liver anabolise?

Answer 36

Enzymes, lipid carrier proteins, albumin and amino acids

Question 37

Can hepatocytes regenerate?

Answer 37

Yes

Question 38

What organelles do hepatocytes contain a lot of?

Answer 38

* mitochondria * peroxisomes * free ribosomes * RER * SER * Golgi bodies * glycogen deposits

Question 39

What is the constitutive secretion of the liver? And what is it’s role?

Answer 39

Bile (bile salts) (ducts —> gall bladder) Used to emulsify fats and help with vitamin K absorption from the small intestine

Question 40

Both the liver and pancreas have endocrine and exocrine functions, how are they different?

Answer 40

In the liver, the same cells (hepatocytes ) execute the exocrine and endocrine functions