Histology Lecture 9 and 10 - Epithelial Glands I and II

Question 1

Describe exocrine glands.

Answer 1

Exocrine glands occur when the epithelial down growth remains connected to the epithelial layer from which it originated. Examples include salivary glands, mammary glands, sweat glands, and sebaceous glands.

Exocrine glands secrete their products via a duct derived from the original connection to the epithelial layer.

Exocrine glands are epithelial outgrowths into underlying connective tissue that retain their connection to the overlying epithelium in the form of one or more ducts.

Question 2

Describe endocrine glands.

Answer 2

Endocrine glands occur when the epithelial down growth degenerates and leaves the secretory tissue isolated from it’s parent epithelial layer. Examples include pituitary, thyroid, pineal, parathyroid, and adrenal glands.

Endocrine glands secrete their products (commonly referred to as hormones) into surrounding blood vessels.

Endocrine glands are epithelial outgrowths into underlying connective tissue that lose their connection to the overlying epithelium. These glands lack ducts and must secrete their product/hormone directly into surrounding blood vessels.

Question 3

What is exocrine secretion?

Answer 3

Exocrine secretion is when the secretory product of a gland is transported via a duct system to the lumen or apical surface of an organ

Question 4

What is endocrine secretion?

Answer 4

Endocrine secretion is when the secretory produce, or hormone, is released directly into the blood in the absence of a duct

Question 5

What is paracrine secretion?

Answer 5

Paracrine secretion is when the secretory product affects neighboring cells.

Question 6

What is autocrine secretion?

Answer 6

Autocrine secretion is when the secretory product affects the cell that released the secretory product.

Question 7

What is the difference between simple and compound multicellular glands?

Answer 7

Simple multicellular glands do not exhibit ductal branching whereas compound multicellular glands do have ductal branching.

Question 8

Describe a simple tubular gland.

Answer 8

A simple tubular gland is a secrtory gland with no excretory duct or a very short excretory duct. The gland opens directly on the epithelial surface.

Example: Intestinal glands of Lieberkuhn

Question 9

Describe a simple coiled tubular gland.

Answer 9

A simple coiled tubular gland has a long excretory duct with a coiled secretory portion.

Example: sweat gland

Question 10

Describe a simple tubular branched gland.

Answer 10

A simple tubular branched gland is when the gland is split into two or more branches, but there is no excretory duct.

Example: Glands of the stomach and uterus

Question 11

Describe a simple acinar/alveolar gland.

Answer 11

A simple acinar/alveolar gland is a gland in which the terminal secretory portion is divided by partitions into sacs called acini or alveoli.

Question 12

What is serous secretion?

Answer 12

Serous secretion is water, enzyme filled secretion.

Question 13

What is mucous secretion?

Answer 13

Mucous secretion is a thick, mucin-containing secretion. Rich in glycoproteins and so stains with PAS

Question 14

What is merocrine secretion?

Answer 14

Merocrine secretion occurs when the secretory product is typically stored in membrane bound vesicles, and the cytoplasm/cell membrane is retrieved in an exocytosis/endocytosis cycle. The cell is not damaged in this process of secretion.

Question 15

What is apocrine secretion?

Answer 15

Apocrine secretion occurs when the apical cytoplasm is released along with the secretory product. Part of the cell is released along with the secretory product.

Example: axillary sweat glands

Question 16

What is holocrine secretion?

Answer 16

Holocrine secretion is when the WHOLE cell is released as part of the secretory product.

Example: Sebaceous glands

Question 17

Describe the submandibular gland.

Answer 17

The submandibular gland is a salivary gland with both serous AND mucous cells. Serous cells form the serous demilune that cap mucous acini. Myoepithelial cells surround these acini.

SubMandibular = Serous and Mucous (Serous more prominent)

Question 18

Describe the sublingual gland.

Answer 18

The sublingual gland is a salivary gland with mucous acini characterized by flattened nuclei at basal poles of the cells. They stain pale with H&E (mucous does not stain well), however, are PAS +ve.

Question 19

Describe the parotid gland.

Answer 19

The parotid gland is a salivary gland with serous acini that stains well with H&E, or other basic dyes. Apical regions contain zymogen granules and the RER predominates in basal regions of secretory cells.

Parrots are serious.

Question 20

What is a compound gland?

Answer 20

A compound gland is a multicellular gland divided into subunits called lobules. Each lobule is equivalent to a simple branched gland.

Question 21

What is parenchyma?

Answer 21

Parenchyma refers to the components of the gland that are derived from epithelium, i.e. secretory units and ducts. These are all cellular structures.

Question 22

What is the stroma?

Answer 22

The stroma is the connective tissue capsule surrounding the entire gland as well as the connective tissue partitions separating the lobules and lobes. These are all connective tissue.

Question 23

What are septa (trabeculae)?

Answer 23

Septa are extensions of the capsule into the epithelial components of the gland that divide the gland into subdivisions called lobes and lobules

Question 24

What are lobes and lobules?

Answer 24

A lobe is a subdivision of a compound gland separated from adjacent lobes by septae.

A lobule is a subdivision of a lobe. Lobules are separated from each other by delicate septae. Each lobule can be thought of as a simple, branched gland.

Question 25

What is an acinus?

Answer 25

An acinus is the secretory component of a lobule. Acini are covered by a basement membrane and thus are epithelial cells.

Question 26

What are myoepithelial cells?

Answer 26

Myoepithelial cells are cells derived from epithelium characterized by extensive actin bundles that lend contractility. They are found between the basement membrane and the secretory cells of the acinus and help to express the secretions of the acini into the intercalated ducts.

Question 27

What are intralobular ducts?

Answer 27

Intralobular ducts are ducts that lie within a lobule. They can be either Intercalated ducts or striated ducts.

Question 28

What are intercalated ducts?

Answer 28

Intercalated ducts are intralobular ducts that drain secretory acini into striated ducts. They are lined by simple squamous/low cuboidal epithelium.

Question 29

What are striated ducts?

Answer 29

Striated ducts are intralobular ducts that actively reabsorb sodium ions, passively reabsorb chloride ions, and actively secrete potassium ions from/to the secretory product. They are lined by cuboidal/columnar epithelium and have pronounced basal striations.

Question 30

What are interlobular ducts?

Answer 30

Interlobular ducts are the confluence of two or more striated ducts found between the septae of adjacent lobules. They are lined with pseudostratified columnar epithelium.

Question 31

That are intralobar ducts?

Answer 31

Intralobar ducts are the confluence of two or more interlobular ducts. They are lined with columnar epithelium transitioning into stratified columnar epithelium.

Question 32

What are lobar ducts?

Answer 32

Lobar ducts are the confluence of two or more intralobar ducts. They are lined with stratified columnar epithelium.

Question 33

What are serous demiliunes?

Answer 33

Serous demilunes are crescent-shapend configurations around the mucous acini formed by serous secretory cells.

Question 34

How can you tell serous acini from mucous acinin with H&E?

Answer 34

Mucous acini do not stain well with H&E while Serous Acini do. Therefore, Serous acini will be darker than mucous acini.