Histology

Question 1

Epithelium

Answer 1

Epithelium = Epethelial Tissue

• Cells closely packed in continuous sheets, little matrix, avascular (no blood vessels) and innervated.
• Basement membrane – anchors epithelium to underlying connective tissue.
• Goblet Cells secrete mucus. Epithelia with goblet cells are mucous membranes.
• Microvilli increase membrane surface area for absorption. Microvilli are non-motile and much smaller than cilia.
• Stereocilia are longer than microvilli and non-motile.
• Cilia – motile, hair-like extensions at free surface.
• Lumen - hollow middle portion of organ/tubular structure.
• Serous membranes – line ventral body cavities. Examples: peritoneum and pleura.

Question 2

Simple Epethelia

Answer 2

• One layer of cells.
• Main functions are:
  o diffusion
  o absorption
  o secretion

Question 3

Simple Squamous Epithelium

Answer 3

a. Flat in a single layer.
b. Selected locations:
i. lining the alveoli (tiny air sacs)
of the lungs
ii. lining blood vessels
iii. serous membranes

Question 4

Simple Cuboidal Epithelium

Answer 4

a. Cube-shaped in a single layer.
b. Selected locations:
i. Lining some kidney tubules
ii. Lining the ducts of many glands.

Question 5

Simple Columnar Epithelium

Answer 5

a. Column-shaped in a single layer.
b. Selected locations:
i. With microvilli, lining the small
intestine
ii. With cilia, lining the uterine tubes.

Question 6

Pseudostratified Columnar Epithelium

Answer 6

a. Single layer of cells.
b. All cells touch the basement membrane,
but not all reach to the apical surface.
Therefore, you see the nuclei of the cells
at different heights with different sizes and
shapes.
c. Selected location:
Lining the trachea (ciliated)

Question 7

Stratified Squamous Epithelium

Answer 7

a. Multiple layers of cells. Cells close to the basement membrane are cuboidal, polyhedral or columnar. Cells become flat as they approach the apical surface.
b. Two types:
i. Keratinized:
1. The apical layers of cells lack nuclei
and no longer living, they are filled
with the protein keratin.
2. Selected locations: the epidermis
(the outer layer of the skin)

ii. Nonkeratinized:
1. The apical layers of cells have nuclei
and are living.
2. Selected locations: lining the mouth,
esophagus, anus and vagina

Question 8

2- Stratified Cuboidal Epithelium:

Answer 8

a. Typically has 2 layers of cuboidal cells.
b. Has a limited distribution in the human body.
c. Selected locations: lining the ducts of sweat glands

Question 9

Stratified Columnar Epithelium:

Answer 9

a. Only its apical cell layer is columnar.
b. Has a limited distribution in the human body
c. Selected locations: lining some glandular ducts
and in parts of the male urethra.

Question 10

Transitional Epithelium

Answer 10

a. Cells in the basal layers are cuboidal while those
In the apical layer are dome-shaped when the
tissue is relaxed and flat when the tissue is
stretched
b. Selected locations: lining the urinary bladder

Question 11

Adipose Connective Tissue (Fat Tissue)

Answer 11

a. White adipose connective tissue appears on a
prepared slide as empty crowded adipocytes
with their nuclei pushed closed to their plasma
membranes.
The empty space was previously occupied by
Large lipid inclusions (droplets) that got extracted
during slide preparation.
b. Selected locations:
i. The hypodermis
ii. Surrounding various organs