Exocrine and Specialised Glands

Question 1

Explain how the majority of ductless glands are derivatives of epithelial tissues

Answer 1

• In utero development an epithelial bud is formed and elongates
• Canaliculariation occurs and central cells die to form a duct

Question 2

Give 3 differences between endocrine and exocrine glands

Answer 2

Endocrine - ductless, secrete hormones into the blood, all epithelial cells secrete the hormone
Exocrine - ducted, secrete enzymes/lubricants via a duct, epithelial cells at duct apex secrete products

Question 3

Name the two shapes of glands

Answer 3

Simple - unbranched duct with single secretory unit

Compound - branched duct with many secretory units

Question 4

What are the two arrangements of cells in a secretory unit? Give a description of each

Answer 4

Acinar (‘grapes’) - small ball of cells with a small central lumen
Tubular

Question 5

Name the 4 duct structures

Answer 5

• Intercalated
• Striated
• Interlobular
• Acini

Question 6

Name a unicellular gland and where are they found and what is their function?

Answer 6

• Goblet cells

- Secrete mucous in jejunum and colon

Question 7

Where are the parotid glands and what is their function?

Answer 7

• Bilateral and positioned in front of the ears on the side of the mouth
• Produce saliva with enzymes to begin digestion and lubricate

Question 8

What type of cell, gland and duct are in the parotid gland and what kind of stimulation is it under?

Answer 8

• Serous acini enclosed in a fibrous capsule
• Serous gland with striated ducts
• Parasympathetic stimulation

Question 9

Where are the submandibular glands and what do they produce?

Answer 9

• Infront of Parotid under the chin
• In 2 parts, superficial and deep
• Serous and mucous gland

Question 10

How are the parotid glands stimulated?

Answer 10

• Control of salivary secretion is neural

- Involves parasympathetic and sympathetic stimulation

Question 11

Briefly describe the blood flow through the liver

Answer 11

• Blood flows from Hepatic Artery through the Hepatic Portal Vein and out through the Central Vein
• Nutrients from stomach and intestine are absorbed followed by release of nutrients and toxins into the Hepatocytes

Question 12

Is the majority of the blood going to the liver oxygenated or deoxygenated?

Answer 12

Deoxygenated

Question 13

What links the major vessels of the liver and what is it composed of?

Answer 13

• Sinusoid tube

- Lined with sinusoid cells and hepatocytes

Question 14

How is the structure of sinusoid cells related to their function?

Answer 14

Sinusoid cells have an incomplete membrane and large intracellular gaps to allow for material exchange with hepatocytes

Question 15

What shape is a liver lobule?

Answer 15

Hexagonal

Question 16

Briefly describe the structure of a liver lobule

Answer 16

• Columns of hepatocytes
• Sinusoids between hepatocytes
• Central vein in the middle
• Portal triad of artery, vein and bile ducts at each corner

Question 17

Name two specialised cells within the liver lobule and describe their function

Answer 17

Kupffer Cell - Move through perforations to phagocytose toxins
Stellate Cell - Full of vacuoles containing Vitamin A

Question 18

Describe 2 hepatocyte specific characteristics

Answer 18

• 80% epithelial cells
• Both endocrine and exocrine
• Adapted organelles for fast transport
• Apical surface on the side of the cell

Question 19

Where are hepatocytes located?

Answer 19

Above and below the bile duct

Question 20

Name the 4 mechanisms of liver signalling

Answer 20

Autocrine - signals target receptors sites on same cell
Paracrine - targets adjacent cells
Endocrine - hormones secreted into blood
Intracrine - hormones stimulate protein production

Question 21

Name the 3 main categories of liver function

Answer 21

• Storage
• Anabolism (production)
• Catabolism (destruction)

Question 22

Name 2 substances the liver stores

Answer 22

• Iron
• Lipid soluble vitamins
• Glycogen
• Copper and minerals

Question 23

Name 2 substances the liver produces

Answer 23

• Albumin
• Enzymes
• Lipid carrier proteins
• Amino acids

Question 24

Name 2 substances catabolised by the liver

Answer 24

• Drugs
• Hormones
• Haemoglobin
• Poisons/Toxins

Question 25

Give 1 endocrine and 1 exocrine function of the liver

Answer 25

Endocrine - Hormone synthesis (angiotensinogen, growth factors)
Exocrine - Bile production

Question 26

What is the location and function of myoepithelial cells in exocrine glands?

Answer 26

• Located near duct opening

- Muscular properties help expel secretions out of the duct

Question 27

What is the purpose of myoepithelial cells in exocrine glands

Answer 27

Contract to squeeze secretory products into and along the duct