epithelia III B

Question 1

The secretions from both exocrine and endocrine glands are generally regulated by:

Answer 1

the autonomic nervous system (i.e. by direct neuronal stimulation), by hormones from blood, or by both.

Question 2

Exocrine glands often secrete

Answer 2

continuously at a low rate but can be triggered to greatly increase the volumes of secretion by these mechanisms.

Question 3

the sight or smell of food stimulates ______

Answer 3

serous secretions from salivary glands, and mucous and serous secretions from gastrointestinal glands.

Question 4

Endocrine secretions tend to be tightly regulated by ______.

Answer 4

hormonal or neuronal stimulation

Question 5

Epithelial tissues are targets _____.

Answer 5

(direct or indirect) of a large variety of diseases

Question 6

Some examples of epithelial diseases are:

Answer 6

diabetes, various liver and kidney diseases, lung diseases (e.g. emphysema, cystic fibrosis), GI disease (e.g. gastric ulcers, inflammatory bowel diseases), skin diseases, hearing diseases, and ciliopathies

Question 7

Examples in the gastrointestinal tract include:

Answer 7

ulcerative colitis, in which extensive ulceration and destruction of the absorptive epithelium occurs.

Question 8

pemphigus is an

Answer 8

autoimmune disease in which antibodies are produced against components of desmosomes in skin, leading to extensive blistering.

Question 9

the broad clinical importance of pemphigus is that:

Answer 9

their relatively high rate of turn-over requiring stem cell-driven renewal, and their exposure to external damage (UV light, pathogens, chemicals).

Question 10

The most common cancers are _______

Answer 10

derived from epithelial tissue, probably because of damage exposure and their high stem-cell driven turnover rates.

Question 11

Cancers of epithelial origin are called _____.

Answer 11

carcinomas

Question 12

cancers derived from glandular epithelium are known as ______

Answer 12

adenocarcinomas.

Question 13

Tumors usually first develop within an ______

Answer 13

epithelial sheet, but they can become invasive and spread (metastasize) to other parts of the body.

Question 14

Often, carcinomas retain _______.

Answer 14

some properties of their tissue of origin.

Question 15

It is now believed that carcinomas result from defects in _____

Answer 15

regulatory pathways that control epithelial stem cells or their progeny during tissue development and maintenance.

Question 16

Targeted regulatory pathways include

Answer 16

1. signaling systems that directly control development (e.g. Wnt, EGF or Notch signaling systems) 2. internal cell cycle control factors
2. factors that control DNA damage repair
3. apoptosis (programmed cell death)

Question 17

the diagnosis and treatment of different carcinomas is aided by _____

Answer 17

histological appearance of the tumor and knowledge of epithelial biology.

Question 18

Epithelia are also important to consider in_____.

Answer 18

wound repair

Question 19

Injuries to skin epithelia that do not extensively damage the basal epithelial stem cells and basal lamina can often be repaired by _____, but if the basal skin layers and basal laminae are severely compromised, _____

Answer 19

intrinsic mechanisms

they are replaced by scar tissue

Question 20

severe burns may require

Answer 20

skin grafts to replace a damaged basal lamina and restore a population of basal skin epithelial stem cells.