Epithelial Tissues & Glands

Question 1

What are the four basic/primary types of tissues?

Answer 1

Epithelial tissues (aka epithelium); connective tissue, muscular tissue, nervous tissue

Question 2

What are the two main categories of epithelial tissues?

Answer 2

1. covering or lining epithelium, 2. glandular epithelium

Question 3

What are the six functions of epithelial tissue?

Answer 3

1. secretion; 2. absorption; 3. filtration; 4 excretion; 5. transport; 6. protection

Question 4

What are the six characteristics of epithelial tissue?

Answer 4

1.cellular; 2.specialized contacts; 3.polarity; 4.supported by connective tissue (lamina propria); 5.avascular, but innervated; 6.regeneration

Question 5

What are the three types of cell layers?

Answer 5

1. simple; 2. stratified, 3. pseudostratified

Question 6

What are the three types of cell height/shape variations?

Answer 6

1.squamous; 2.cuboidal, 3.columnar

Question 7

Describe simple layer of cells.

Answer 7

This is one layer of cells

Question 8

Describe stratified layer of cells.

Answer 8

This is several layers of cells thick.

Question 9

Describe pseudostratified layer of cells.

Answer 9

This is a layer that resembles a stratified layer however it is not stratified because all of the cells are in contact with the basement membrane.

Question 10

Describe what a squamous cell looks like?

Answer 10

flattened with flattened nucleus from the side, look like irregular tiles from the top.

Question 11

Describe what cuboidal cells look like?

Answer 11

Cubes with the nucleus in the center.

Question 12

Describe what columnar cells look like?

Answer 12

Columnar cells are taller than they are wide and the nucleus are typically closer to the basement memrane

Question 13

Describe transitional epithelium and what is it also called?

Answer 13

This is also called urothelium because it lines the bladder and has umbrella cells on the apical surface. These umbrella cells have the ability to stretch when the bladder is distended.

Question 14

What are the four components involved in tissue naming?

Answer 14

Surface specialization + number of cell layers + cell morphology + tissue

Question 15

What kind of tissue is in the air sacs of the lungs?

Answer 15

Simple squamous epithelium

Question 16

What kind of tissue is in distal and proximal convoluted tubules of the kidney?

Answer 16

simple cuboidal epithelial cells

Question 17

What are the primary functions of simple cuboidal epithelium?

Answer 17

Secretion and absorption

Question 18

What are the mucous secreting unicellular glands that are associated with simple columnar epithelium?

Answer 18

Goblet cells

Question 19

What is the function of simple columnar epithelium?

Answer 19

Absorption; secretion of mucous, enzymes, and other substances; ciliated type propels mucus (or reproductive cells) by ciliary action

Question 20

What is the function of stratified squamous epithelium?

Answer 20

Protects underlying tissues in areas subjected to abrasion

Question 21

Nonkeratinized stratified squamous epithelium lines what?

Answer 21

Moist linings of esophagus, mouth and vagina

Question 22

Keratinized stratified squamous epithelium lines what?

Answer 22

The epidermis of the skin

Question 23

What is a function of stratified columnar epithelium?

Answer 23

Protection and secretion

Question 24

What does ciliated pseudostratified columnar epithelium line?

Answer 24

Trachea, most of the upper respiratory tract

Question 25

What is the function of transitional epithelium?

Answer 25

Permits distension

Question 26

What are the three distinct polarities of epithelial cells?

Answer 26

Apical domain, lateral domain, and basal domain

Question 27

What are microvilli?

Answer 27

Cytoplasmic extensions/processes with core fo actin filaments

Question 28

What are the function of microvilli?

Answer 28

Increase surface area

Question 29

What are the names of the two kinds of borders created with microvilli?

Answer 29

Striated border (intestinal epithelium) or brush border (kidney tubule cell)

Question 30

What are the average height and width of microvilli?

Answer 30

1 micrometer tall and 0.08 micrometer wide

Question 31

If a cell has microvilli what is a good estimation of its function?

Answer 31

Absorption because microvilli increases surface area

Question 32

What are stereocilia?

Answer 32

Long microvilli

Question 33

Where are stereocilia found?

Answer 33

Epididymis, proximal part of the ductus deferens, and inner sensory cells of the ears

Question 34

What do cilia do?

Answer 34

produce movement by rapidly moving back and fourth

Question 35

What does cilia contain that causes motion?

Answer 35

An axoneme

Question 36

What to the microtubules of the cilia insert themselves into?

Answer 36

The basal bodies

Question 37

What is the length and diameter of cilia?

Answer 37

length is 5-10 micrometers and diameter is 0.2 micrometers

Question 38

What are the three components of the junctional complex?

Answer 38

1)zona occludens or tight junctions; 2)zona adherens; 3)macula adherens or desmosomes

Question 39

What is the main reason that zona occludens aka tight junctions seal off intercellular space?

Answer 39

Items must be actively transported across via the special membrane proteins of epithelial cells. They cannot simply slip between.

Question 40

What is the main function of the zona adherens?

Answer 40

Mechanical anchoring.

Question 41

How do the zona adherens provide mechanical stability to microvilli?

Answer 41

linking cytoskeletal microfilaments (actin) via plaque on the inside of PM which is attached to a cadheren which then attaches to the cadheren on the adjacent cell which crosses the PM

Question 42

What does macula adherens (desmosome) help do and how?

Answer 42

This is a type of anchoring junction like spot welding of metal. This junction is not continuos around the cell like the other two components of the junctional complex.

Question 43

What specifically do macula adherens (desmosomes) attach?

Answer 43

intermediate filaments

Question 44

What are gap junctions?

Answer 44

These are communicating junctions that form a communicating tunnel.

Question 45

What is a connexon?

Answer 45

This is a communicating tunnel formed by connected connexins.

Question 46

Basement membrane is a term only used in what type of microscopy?

Answer 46

Light microscopy

Question 47

What are the two components of the basal lamina and are they actually separate structures?

Answer 47

There is the lamina lucida and the lamina densa. There is only one real structure which is the basal lamina, the basal lucida is an artifact created with osmium tetroxide staining.

Question 48

What is a focal adhesion?

Answer 48

This anchors microtubules (actin filaments) of the cytoskeleton to the basement membrane

Question 49

What are hemidesmosomes?

Answer 49

These are structures that anchor intermediate filaments to the basement membrane.

Question 50

What is a functional role of a focal adhesion?

Answer 50

Signal detection and transmitting signals from the extracellular environment into the interior of the cell; mechanosensitivity.

Question 51

What are the two main categories of epithelial tissue?

Answer 51

Covering or lining epithelium and glandular epithelium

Question 52

Define an endocrine gland?

Answer 52

This gland is ductless; secrete into interstitial fluid

Question 53

Define exocrine gland?

Answer 53

This gland secretes their products onto a surface either directly or via an epithelial duct

Question 54

Endocrine glands can release hormones in what three ways?

Answer 54

Circulatory, paracrine, and autocrine

Question 55

How are most human hormones secreted?

Answer 55

Circulatory endocrine glands

Question 56

Exocrine glands can be classified based on what four things?

Answer 56

1.cellularity; 2.structure; 3.type of secretion; 4.mode/mechanism of secretion

Question 57

What is a good example of a unicellular exocrine gland?

Answer 57

Goblet cells, produce and secrete mucin

Question 58

The structure of an exocrine duct can be what two things?

Answer 58

Simple (branched) or compound (2 or more branches)

Question 59

What are the three structures of secretory units?

Answer 59

1.tubular; 2.alveolar or acinar; 3.tubuloalveolar and tubuloacinar-combination

Question 60

Exocrine glands can be based on their 3 types of secretion which are what?

Answer 60

Mucous, serous, and mixed

Question 61

Serous cells secrete what?

Answer 61

Proteins, typically digestive enzymes

Question 62

What to serous cells look like?

Answer 62

Pyramidal in shape

Question 63

What is the difference in the nuclei between serous and mucous cells?

Answer 63

Serous cells have round nuclei and mucous cells have flattened nuclei

Question 64

What do mucous cells produce?

Answer 64

Hydrophilic glycoprotein mucins

Question 65

What do mucous cells look like?

Answer 65

Cuboidal in shape

Question 66

What are myoepithelial cells?

Answer 66

These are found within the basal lamina of secratory units and the initial part of duct system, they can contract to accelerate secretion of product and prevent distortion when lumen fills.

Question 67

What is the basic unit of the salivary gland?

Answer 67

Salivon, and is composed of the acinus and all related ducts

Question 68

What are the three secretory acini found in salivary glands?

Answer 68

Serous (spherical), mucous (tubular) and mixed

Question 69

What are serous demilunes?

Answer 69

These are part of mixed acini salivary glands. Specifically they are serous cell caps on the mucous acini. These are found in the sublingual and submandibular salivary glands. This happens because of conventional fixation.

Question 70

What are the three types of secretions from exocrine glands?

Answer 70

Merocrine, apocrine, and holocrine

Question 71

Merocrine secretes its product in what way?

Answer 71

Secretory vesicle binds with PM and releases product

Question 72

Holocrine secrets its product in what way?

Answer 72

A mature cell dies and becomes the secretory product.

Question 73

Apocrine secretes its product in what way?

Answer 73

pinched off portion of cell becomes secretion. Closest thing to this in humans is breast milk however there is no cytoplasm in breast milk so it is not the same.