Four Marks Questions

1. Give an account of grandular epithelium?
A: Grandular epithelium have a columnar or cuboidal cells, these are produce some secretions. The glands are two types
1) Unicellular glands (goblet cells of the gut).
2) Multicellular glands (Cluster cells of salivary glands). 
Multicellular glands divided into two types.
     i) Exocrine glands      ii) Endocrine glands
Exocrine glands: These are provided with ducts, secrete mucus, saliva, earwax (cerumen), oil, milk, digestive enzymes.
Endocrine glands: These are ductless glands. Their products are hormones. Based on the mode of secretion exocrine glands are 3 types:
Merocrine glands: The secretory granules without the loss of other cellular material.
e.g.: Pancreas.
Apocrine glands: Apical part of the cell in pinched off along with the secretory product. e.g.: Mammary glands.
Holocrine glands: The entire cell disintegrates to discharge the contents.
e.g.: Sebaceous glands.

Two Marks Questions
 

1. What is cephalization? How is it useful to its processors?
A: Concentration of nerve and sensory cells at locate anterior end. It is usefull for sense the new environment and respond more efficiently and quickly.
 

2. Distinguish between exocrine and endocrine glands with example.
A: Exocrine glands are provided with ducts.
e.g.: Saliva, Earwax.
Endocrine glands are ductless and their products are hormones. e.g.: Pancreas, Sebaceous glands.
 

3. Distinguish between holocrine and apocrine glands?
A: Holocrine the entire cell disintigrates to discharge the contents. e.g.: Sebaceous glands.