2.4

Question 1

These surfaces may possess specialized structures such as microvilli, stereocilia, and cilia.

Answer 1

Apical Epithelial Surfaces

Question 2

Apical Epithelial Surfaces

Answer 2

• Microvilli
• Stereocilia
• Cilia

Question 3

• Microvilli
• Stereocilia
• Cilia

Answer 3

Apical Epithelial Surfaces

Question 4

__________are fingerlike projections of epithelia approximately 1 _m long that extend into a lumen and increase the cell’s surface area.

Answer 4

Microvilli

Question 5

Microvilli

Answer 5

1. A glycocalyx (sugar coat) is present on their surfaces.
2. A bundle of approximately 30 actin filaments runs longitudinally through the core of each microvillus and extends into the terminal web, a zone of intersecting filaments in the apical cytoplasm.
3. Microvilli constitute the brush border of kidney proximal tubule cells and the striated border of intestinal absorptive cells.

Question 6

Microvilli:

A ___________(sugar coat) is present on their surfaces

Answer 6

Glycocalyx

Question 7

Microvilli:

A bundle of approximately ___________ runs longitudinally through the core of each microvillus and extends into the ___________________, a zone of intersecting filaments in the
apical cytoplasm

Answer 7

30 actin filaments; Terminal web

Question 8

Microvilli:

A zone of intersecting filaments in the apical cytoplasm

Answer 8

Terminal web

Question 9

Microvilli:

Microvilli constitute the brush border of _________ proximal tubule cells and the striated border of _________absorptive cells

Answer 9

Kidney; Intestinal

Question 10

_____________are very long microvilli (not cilia) in the epididymis and vas deferens of the male reproductive tract.

Answer 10

Stereocilia

Question 11

Stereocilia are very long microvilli (not cilia) in the __________ and _____________ of the male reproductive tract.

Answer 11

Epididymis; Vas deferens

Question 12

_________ are actively motile processes 5 to 10 _m long extending from certain epithelia (e.g., tracheobronchial and oviduct epithelium) that propel substances along their surfaces. They contain a core of longitudinally arranged microtubules (the axoneme), which arises from a basal body during ciliogenesis.

Answer 12

Cilia

Question 13

Cilia are actively motile processes ______ _m long extending from certain epithelia (e.g., tracheobronchial and oviduct epithelium) that propel substances along their surfaces. They contain a core of longitudinally arranged microtubules (the axoneme), which arises from a basal body during ____________.

Answer 13

5 to 10; Ciliogenesis

Question 14

Cilia

Answer 14

1. The axoneme consists of nine doublet microtubules uniformly spaced around two central microtubules (9 _ 2 configuration), as well as the following components:
   a. Ciliary dynein arms, which extend unidirectionally from one member of each doublet microtubule and interact with adjacent doublets, so that they slide past one another. These arms consist of ciliary dynein, with a head that is an ATPase that splits ATP to liberate the energy necessary for active movement of a cilium.
   b. Radial spokes that extend from each of the nine outer doublets toward the central sheath.
   c. Central sheath, which surrounds the two central microtubules; it and the radial spokes regulate the ciliary beat.
   d. Nexin, an elastic protein that connects adjacent doublet microtubules and helps maintain the shape of the cilium.
2. The basal body is a cylindrical structure at the base of each cilium that consists of nine triplet microtubules arranged radially in the shape of a pinwheel (9 _ 0 configuration). It resembles a centriole but has a less complex central organization. The inner two triplets of the basal body give rise to the doublet microtubules of the cilium axoneme.

Question 15

Cilia

Answer 15

• Axoneme
• Basal Body

Question 16

• Axoneme
• Basal Body

Answer 16

Cilia

Question 17

Cilia:

The _________ consists of nine doublet microtubules uniformly spaced around two central microtubules (9 _ 2 configuration)

Answer 17

Axoneme

Question 18

Cilia:

The axoneme consists of _____ doublet microtubules uniformly spaced around ____ central microtubules (9 _ 2 configuration)

Answer 18

9; 2

Question 19

Axoneme

Answer 19

• Ciliary dynein arms
• Radial spokes
• Central sheath
• Nexin

Question 20

• Ciliary dynein arms
• Radial spokes
• Central sheath
• Nexin

Answer 20

Axoneme (Cilia)

Question 21

Cilia - Axoneme:

__________, which extend unidirectionally from one member of each doublet microtubule and interact with adjacent doublets, so that they slide past one another. These arms consist of ciliary dynein, with a head that is an ATPase that splits ATP to liberate the energy necessary for active movement of a cilium.

Answer 21

Ciliary dynein arms

Question 22

Cilia - Axoneme:

___________ that extend from each of the nine outer doublets toward the central sheath.

Answer 22

Radial spokes

Question 23

Cilia - Axoneme:

_____________ , which surrounds the two central microtubules; it and the radial spokes regulate the ciliary beat.

Answer 23

Central sheath

Question 24

Cilia - Axoneme:

________, an elastic protein that connects adjacent doublet microtubules and helps maintain the shape of the cilium.

Answer 24

Nexin

Question 25

The_____________ is a cylindrical structure at the base of each cilium that consists of nine triplet microtubules arranged radially in the shape of a pinwheel (9 _ 0 configuration). It resembles a centriole but has a less complex central organization. The inner two triplets of it give rise to the doublet microtubules of the cilium axoneme.

Answer 25

Basal body

Question 26

The basal body is a cylindrical structure at the base of each cilium that consists of nine triplet microtubules arranged radially in the shape of a pinwheel (9 _ 0 configuration). It resembles a _________ but has a less complex central organization. The inner two triplets of the basal body give rise to the doublet microtubules of the cilium axoneme.

Answer 26

centriole