Glands Introduction

Question 1

Define a gland

Answer 1

An epithelial cell or aggreate of a cell that are specialised for the secretions of a substance

Question 2

W what are three features of an endocrine gland ?

Answer 2

1) secrete directly into the blood
2) secrete hormones

3 all epithelial cells secrete hormones from the gland

Question 3

What is the main endocrine gland called ?

Answer 3

Pituitary gland

Question 4

Where is the pituitary gland located ?

Answer 4

Beneath the hypothalamus

Question 5

What are two examples of hormones that the posterior pituitary gland secretes ?

Answer 5

1) oxytocin

2) ADH ( vasopressin)

Question 6

What are 5 examples of hormones that are secreted by the anterior pituitary gland ?

Answer 6

1) T-SHIRT ( thyroid stimulating hormone )
2) adrenocorticotropin hormone
3) LH
4) follicle stimulating hormone
5) prolactin

Question 7

Give 5 examples of exocrine glands

Answer 7

1) mammalian gland
2) salivary gland
3) sweat gland
4) sebaceous gland
5) lachymal gland

Question 8

What is myoepithalial cells ?

Answer 8

• found in glands that are often a mixture of exocrine and endocrine
• they have features of smooth muscle and epithelial cells.
• they help eject secretions from the duct

Question 9

What type of duct does not exist in an adult ?

Answer 9

• simple alveolar

Question 10

What are the three modes of secretion ?

Answer 10

• merocrine
• apocrine
• Holocrine

Question 11

What is merocrine secretion and give an example ?

Answer 11

1) vesicles fuse with the plasmolemma and released through the process of exocytosis.

• an example would be insulin secretion
• this is where ATP increase blocks sensitive k+ channels which causes depolarisation in the beta cell which causes Ca2+ channels open causing ca2+ to enter.

Question 12

What is apocrine secretion ?

Answer 12

• partial loss of cytoplasm
• only fats are secretes by apocrine glands
• for example mammary glands during lactation period , sweat glands in underarms and genitalia.
• lipid comes. Into contact with apical membrane and pushes against it.
• thin layer of apical membrane surrounds it.
• this membrane then pinches off the cell.

Question 13

What is holocrine secretion and give an example ?

Answer 13

Complete loss of cytoplasm.

• an example would be the sebaceous gland in the skin and tarsal gland in the eyelid.
• secretarory cells fill up with secretory granules.
• the cell organelles degenerate and cell dies.
• plasma membrane breaks and cell empties contents

Question 14

Wheat are the three destinations the contents of Golgi apparatus ?

Answer 14

1) vesicles
2) some retained for use inside cells
3) some enters plasma membrane

Question 15

Pdefine glycosylation

Answer 15

Use of enzymes to covalently attach sugars to lipids and proteins.

Question 16

What are 4 roles of glycolysation ?

Answer 16

1) prevent protein digestion by protease
2) prevent lipid digestion by lipases
3) aid protein folding
4) aid cell recognition

Question 17

Define exocytosis

Answer 17

Secretion of molecules outside the cell through vesicles fusing to a membrane

Question 18

Define endocytosis

Answer 18

Engulfing of molecules inside the cell via vesicle formation

Question 19

Define phagocytosis

Answer 19

The process by which phagocytes engulf / envelop other cells

Question 20

Define pinocytosis

Answer 20

• process in which liquid droplets are indigested by cells.

Question 21

What form of transepithalilal transport do impermeable substances use ? Eg cholesterol

Answer 21

• this is where material is endocytosed at one end of the surface and exocytosed at another end.

Question 22

What what form of transepithalial transport do amino acids use ?

Answer 22

• they move through the intracellular junction

Question 23

What form of transepithelilal transport do steroid hormones use ? Eg testosterone , oestrogen , progesterone

Answer 23

Directly through the lipid membrane

Question 24

How is thyroxine transported across the epithelium?

Answer 24

• via carrier proteins