HISTOLOGY - Epithelial tissues

In embryogenesis the epithelia are derived from: mesoderm (2) ectoderm (3) endoderm (4) mesenchyme

1,2,3

The epithelia are specialized for the following functions: (1) mechanical and chemical protection (2) outer exchange (3) secretion (4) maintenance of homeostasis

1,2,3

The following characteristics of the epithelia are true: (1) line internal and cover external body surfaces (2) are avascular (3) rest on the basement membrane (4) abound in the extracellular substance

1,2,3

The following statements regarding the apocrine mode of secretion are true: (1) inheres in some sweat glands (2) inheres in the mammary gland (3) is characterized by releasing the apical cell cytoplasm with secretory material (4) its mechanism is exocytosis

1,2,3

The specializations of epithelial cells on the lateral surface are as follows: (1) tight junctions (2) desmosomes (3) nexuses (4) hemidesmosomes

1,2,3

The stratified squamous keratinized epithelium from the thin skin in comparison with the same epithelium from the thick skin is characterized by the following: (1) lacks the stratum lucidum (2) contains the poor-developed stratum granulosum (3) contains the thin stratum corneum (4) lacks the stratum spinosum

1,2,3

The following statements regarding the holocrine mode of secretion are true: (1) inheres in sebaceous glands (2) its mechanism is exocytosis (3) is characterized by releasing the entire cell with secretory material (4) inheres in sweat glands

1,3

The specializations of epithelial cells on the basal surface are as follows: (1) hemidesmosomes (2) desmosomes (3) plasma membrane infoldings (4) nexuses

1,3

The specializations of epithelial cells on the apical surface are as follows: (1) hemidesmosomes (2) microvilli (3) nexuses (4) cilia

2,4

The following statements regarding the merocrine mode of secretion are true: (1) is characterized by releasing the apical cell cytoplasm with secretory material (2) inheres in sebaceous glands (3) is characterized by releasing the entire cell with secretory material (4) its mechanism is exocytosis

4

Each of the following statements concerning the stratified transitional epithelium is true, EXCEPT: A - is capable of keratinization; B - consists of the basal, intermediate, and superficial layers; C - changes the number of its layers, depending on the degree of stretching; D - its superficial cells are dome-shaped; E - lines the urinary system organs.

A

The cardinal features of the epithelia are as follows, EXCEPT: A - form the stroma of organs; B - look like sheets; C - are derived from all germ layers; D - regenerate intensively; E- their cells are polarized.

A

Each of the following statements concerning the basement membrane is true, EXCEPT: A - separates epithelium from the underlying connective tissue; B - is absent in some epithelia; C- contains type lV collagen and laminin; D - serves for epithelial cell attachment; E - takes part in nutrition of epithelium.

B

Each of the following statements concerning the pseudostratified epithelium is true, EXCEPT: A - all its cells rest on the basement membrane; B - all its cells reach the apical surface; C - contains goblet cells; D - is ciliated; E - contains short (basal) cells.

B

Each of the following statements concerning a compound branched tubuloalveolar gland is true, EXCEPT: A - its duct branches; B - its secretory portions are numerous; C - it has one secretory portion; D - its secretory portions may be flask-like; E - its secretory portions may be tube-like.

C

Each of the following statements concerning the stratified squamous nonkeratinized epithelium is true, EXCEPT: A - contains the spinulate cell layer; B - contains the basal layer with stem cells; C - contains the superficial layer of flat anucleate cells; D - its superficial cells are continuously sloughed; E - lines the oral cavity, the esophagus, the rectum, and the vagina.

C

The epithelia are simple if: A - their cells are polarized; B - their cells form sheets; C - all their cells rest on the basement membrane; D - not all their cells reach the apical surface; E - their cells are continuously sloughed.

C

Each of the following statements concerning the mesothelium is true, EXCEPT: A - is derived from mesoderm; B - is simple; C - its cells are squamous; D - not each of its cells reaches the lumen; E - lines the peritoneal cavity.

D

The criteria of the exocrine gland classification are as follows, EXCEPT: A - branching of the duct; B - the number of secretory portions; C - the shape of secretory portions; D - contact of cells with the basement membrane; E - the mode of secretion.

D

The epithelia are stratified if: A - their cells are continuously sloughed; B - their cells form sheets; C - their cells are polarized; D - all their cells can divide; E - not all their cells are in contact with the basement membrane.

E

Absorption is the main function of the small intestine lined with the epithelium. What type of epithelia is adequate to this function?

Epithelium of the small intestine is simple columnar striated and specialized for absorption. It consists of tall columnar cells (absorptive cells) resting on the basement membrane. Apical portions of the epitheliocytes have numerous microvilli that form the brush border.

The cells of the stratified squamous keratinized epithelium are cultivated in two flasks. One of them contains the stratum basale cells; the other flask contains the stratum lucidum cells. Which of the flasks will contain proliferating cells?

Proliferating epithelial cells may be found in the flask with the stratum basale cells, because this layer is cambial and contains stem cells. The stratum lucidum consists of differentiating cells that lack mitotic capacity.

The brush border on the epithelial cells of the small intestine can be destroyed in some diseases (sprue). What cell functions are impaired in this case?

The brush border of the intestinal epithelium enlarges the cell surface area for absorption and membrane digestion. If the brush border is destroyed, these functions are impaired.

The stratified squamous keratinized epithelium covers the skin. Are there any differences in the structure of the epithelium covering the thick (hairless) skin and the epithelium covering the thin skin?

The epithelium covering the thick skin consists of five distinct layers: the stratum basale, the stratum spinosum, the stratum granulosum, the stratum lucidum, and the stratum corneum. The epithelium covering the thin skin consists of only four layers, because it lacks the stratum lucidum. Its stratum granulosum is poor-developed; its stratum corneum is thin.

There are two epithelia in the histological section of an organ. One of them covers the surface of the organ; the other epithelium is located in the wall depth of the organ. Specify the epithelia and suggest their functions.

The epithelium that covers the surface of the organ is the covering epithelium. Its main functions are protection and external exchange. The epithelium located in the wall depth of the organ is glandular epithelium that forms exocrine and some endocrine glands. Its main function is secretion.

The epithelium lining the intestine is characterized by the following features: (1) contains goblet cells (2) is simple columnar (3) has the brush border (4) is specialized for absorption

all

The following statements regarding the stratified squamous keratinized epithelium are true: (1) its basement membrane is sinuous (2) covers the skin (3) its basal layer contains stem cells (4) its superficial cells are flat and anucleate

all