Chapter One - Epithelium Flashcards
0
Q
What are the three general functions of epithelium?
A
Absorption, secretion, and providing a barrier
1
Q
What are the four basic types of tissue?
A
Epithelial, muscle, nervous, and connective
2
Q
Which general function of epithelium is a function of ALL epithelium?
A
Providing a barrier
3
Q
What produces the basal lamina of the basement membrane?
A
Epithelium
4
Q
What are the three specialized functions of epithelium?
A
Transfer molecules across epithelium, prevent transfer of materials (aka selective permeability), sensory function
5
Q
What produces the reticular lamina in the basement membrane?
A
Fibroblasts in connective tissue
6
Q
What are the two parts of the basement membrane of epithelium?
A
Basal lamina and reticular lamina
7
Q
What makes up a partial basement membrane of epithelium?
A
Basal lamina ONLY
8
Q
What are the functions of the basement membrane of epithelium?
A
Providing a surface for epithelial cell attachment, molecular filter (very limited), limits stretch, and directs migration of cells
9
Q
Are epithelial cells vascular or avascular?
A
Avascular
10
Q
By what process do epithelial cells obtain nutrition?
A
Diffusion
11
Q
What are the functions of connective tissue?
A
Provides nutrition (and oxygen), source of defensive cells
12
Q
Which type of cell junction involves the sharing of intrinsic membrane proteins between adjacent cells?
A
Zonula occludens
13
Q
What is the other name for zonula occludens?
A
Tight junction
14
Q
What are the functions of zonula occludens (tight junctions)?
A
Provides strong attachment, prevents the passage of materials between cells
15
Q
Zonula adherens consist of what?
A
Cadherins (linkage proteins) and marginal bands (microfilaments)
16
Q
What part of the zonula adherens are located between cells?
A
Cadherins
17
Q
What is the other name for zonula adherens?
A
Adhesion belt
18
Q
What part of the zonula adherens attach the cytoskeleton to the cell membrane?
A
Marginal bands
19
Q
What are the functions of the zonula adherens?
A
Strong attachment and provide cell structural stability
20
Q
What is another name for macula adherens?
A
Desmosome
21
Q
What is the function of macula adherens?
A
Provides strong attachment
22
Q
What are the three parts of the macula adherens?
A
Transmembrane proteins, protein plaque, and tonofilaments
23
Q
Which type of cell junction is arranged in a cylinder with six connexins (proteins)?
A
Gap junctions
24
What are the two functions of gap junctions?
Strong attachment, transport materials between cells
25
What makes up the junctional complex (in order)?
Zonula occludens, zonula adherens, macula adherens
26
What junctions hold the epithelium to the basement membrane and the connective tissue below?
Hemidesmosomes and focal point contacts
27
What is the function of hemidesmosomes?
Helps connect epithelial cells to the basal lamina (essentially half a desmosome)
28
What is bullous pemphigoid?
An autoimmune skin disease causing large blistering lesions that burst but do heal
29
What is pemphigus vulgaris?
An autoimmune skin disease causing skin blistering that do not heal easily; excessive bleeding is likely & can be fatal
30
What is cholera?
Acute bacterial infection of the small intestines
31
What is the cause of bullous pemphigoid?
Antibodies bind to some proteins in hemidesmosomes
32
What is the cause of pemphigus vulgaris?
Antibodies bind to some parts of desmosomes
33
What is the cause of cholera?
Toxins disrupt proteins in the zonula occludens which permits the loss of water and electrolytes from the connective tissue below the epithelium
34
What is the general name for the type of epithelium that is one cell thick?
Simple epithelium
35
What type of simple epithelium is a single layer of flattened cells?
Simple squamous
36
What type of epithelium is found in the lungs, parietal layer of the Bowman's capsule in the kidney, and the serosa on the outside of organs?
Simple squamous
37
What are the functions of simple squamous epithelium?
Living filter, provide a barrier
38
What type of simple epithelium is located in exocrine ducts, thyroid follicular cells, and the proximal and distal convoluted kidney tubules?
Simple cuboidal
39
What are the functions of simple cuboidal epithelium?
Absorption, secretion, provide a barrier
40
What type of simple epithelium is one layer of cube shaped cells?
Simple cuboidal
41
What type of simple epithelium represents a single layer of rectangular shaped cells that appear vertical?
Simple columnar
42
What type of epithelium is located in the stomach, small intestines, gallbladder, colon, and larger exocrine ducts?
Simple columnar
43
What are the functions of simple columnar epithelium?
Absorption, secretion, provide a barrier
44
What type of simple epithelium is also known as respiratory epithelium?
Ciliated pseudostratified columnar epithelium
45
What type of simple epithelium is located in the trachea, respiratory region of nasal cavity, and the bronchi?
Ciliated pseudostratified columnar epithelium
46
What is the function of goblet cells?
Produce and secrete mucus
47
Ciliated pseudostratified columnar epithelium is made up of what three types of cells?
Goblet cells, ciliated columnar cells, and basal cells
48
What is the function of the ciliated columnar cells found in ciliated pseudostratified columnar epithelium?
To move mucus over the membrane
49
What type of cell in respiratory epithelium does not reach the surface?
Basal cells
50
What is the function of the basal cells of respiratory epithelium?
To be the stem cell of that type of epithelium (proliferation and differentiation)
51
What are the finger like projections at the apical surface on some epithelial cells?
Microvilli (brush border or striated border)
52
What is the function of microvilli?
To increase surface area so as to increase absorption
53
What are good example locations of microvilli?
Kidney tubule cells and small intestines
54
What are extremely long microvilli?
Stereocilia
55
Where can stereocilia be found?
Epididymis, cochlear hair cells
56
What is the function of stereocilia?
To increase surface area
57
Are stereocilia considerably motile?
No, less motile; they are actually quite rigid with actin core (not related to true cilia)
58
What is the function of cilia?
To move something over a surface
59
What are the apical hair-like extensions of the cytoplasm that function in movement?
Cilia
60
What are good examples of ciliary locations?
Trachea and fallopian tube
61
What organelle is largely seen in cilia?
Mitochondria
62
What anchors cilia?
Basal bodies
63
What is the result of basal bodies in cilia blocking the free surface?
No absorption or secretion
64
What is the surface layer of glycoproteins and carbohydrates that covers some epithelium?
Glycocalyx
65
What produces the glycocalyx?
Epithelial cells
66
What are the functions of the glycocalyx?
Protection and cell recognition
67
What are other possible functions of the glycocalyx?
Cell adhesion and holds enzymes
68
What are example locations of the glycocalyx?
Stomach and small intestines
69
What type of epithelium is two or more cell layers thick?
Stratified epithelium
70
What is the general function of all stratified epithelium?
Protection
71
Types of stratified epithelium are named after what cells?
Superficial layer of cells
72
What type of stratified epithelium has multiple layers of cells that seem to flatten out from the basal layer to the superficial layer & the superficial layer of cells are flat and alive?
Stratified squamous epithelium
73
What type of epithelium is found in the esophagus, oral cavity, tongue, and vagina?
Stratified squamous epithelium
74
What is the general function of stratified squamous epithelium?
Protection from abrasion/friction
75
What is the type of epithelium of the skin?
Keratinized stratified squamous epithelium
76
What are some limitations of stratified squamous epithelium?
No protection from drying and limited thickness leading to limited protection
77
What is the function of keratinized stratified squamous epithelium?
Protection in a dry environment
78
What are the layers of the skin?
Stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum
79
Which layer of the skin is made of dead cells, keratin, and lipids?
Stratum corneum
80
What are the three general functions of the stratum corneum?
Prevents water loss, provides a barrier to microbes, protects against abrasion
81
Which two layers of the skin are layers where cell division can occur?
Stratum basale and stratum spinosum
82
Which layer of the skin is closest to the dermis and is made up of 1-2 layers of mitotic keratinocytes?
Stratum basale
83
Where are melanocytes found?
Stratum basale
84
What is the general function of melanocytes?
Protect from UV radiation
85
What cells determines skin color?
Melanocytes
86
Which type of melanin is known to represent darker pigments?
Eumelanin
87
Which type of melanin represents a reddish color?
Pheomelanin
88
What three things influence skin color?
Environment, genetics, number of blood vessels in the dermis
89
True or false: everyone has the same number of melanocytes.
True! The difference is the production of melanin of each melanocyte
90
Where are Langerhans cells located?
Stratum spinosum
91
What is the function of the Langerhans cells?
Recognize and process foreign antigens (APC)
92
What effect does UV radiation have on Langerhans cells?
Reduction
93
What type of epithelium can be found in the sweat and salivary glands?
Stratified cuboidal epithelium
94
What effect does repeated UV exposure have on melanocytes?
Increased numbers
95
What are the functions of stratified cuboidal epithelium?
To increase protection and provide a barrier
96
What are the functions of stratified columnar epithelium?
Increase protection, provide a transition between epithelial types, provide a barrier
97
What cells are known as the epithelial tactile cells?
Merkel cells
98
Merkel cells are located in what layer of the skin?
Stratum basale
100
What layer of the skin is associated with free nerve endings?
Stratum basale (due to Merkel cells)
101
The function of taste buds and the retina of the eye are examples of what specialized function that can be possessed by epithelium?
Sensory
102
What transmembrane protein of the cell membrane binds to structural connective tissue glycoproteins and also connects to cytoskeleton?
Integrin (focal point contacts)
103
During the stem cell division of one basal cell of respiratory epithelium, what are the two daughter cell types?
One basal cell and one goblet cell/ciliated columnar cell (2 total)
104
What covers the superficial cell layer of keratinized stratified squamous epithelium?
Nonliving layer of keratin
105
What is another term for the stratum basale?
Stratum germinativum
106
Which layer of the skin contains multiple layers of "spiny shaped" keratinocytes?
Stratum spinosum
107
What do the keratinocytes found in the stratum spinosum produce?
Lipids and keratohyaline vacuoles
108
In which layer of the skin does exocytosis of lipid-filled lamellar granules occur?
Stratum granulosum
109
Which layer of the skin is only present in thick skin, is difficult to see, and does not contain nuclei or organelles?
Stratum lucidum
110
What structures contribute strength to keratinized stratified squamous epithelium by increasing surface area of attachment of the epithelium to the connective tissue below?
Epidermal pegs (rete ridges)
111
What is the relative half life of skin cells?
28 days
112
What type of epithelium is likely to be seen in the large ducts in the pancreas, parts of the male urethra, and the conjunctiva of the eye?
Stratified columnar
113
What is the appearance of the basal layer of stratified columnar epithelium?
Flattened to cuboidal in shape
114
What is the frequency of stratified columnar epithelium in the body?
Rare
115
What is another name for transitional epithelium?
Urinary epithelium or urothelium
116
What is the microscopic appearance of the basement membrane and nuclei of transitional (urinary) epithelium?
Straight basement membrane and round nuclei
117
What type of epithelium makes up most of the urinary tract?
Transitional epithelium
118
What are the functions of transitional (urinary) epithelium?
Provide protection, to stretch, act as a barrier
119
What is the basement membrane structure of transitional epithelium?
Thin and fenestrated
120
What type of cell junction is well-developed with transitional (urinary) epithelium?
Zonula occludens (tight junctions)
121
Why is it important for transitional (urinary) epithelium to have well-developed tight junctions?
Extra support is needed due to the fenestrated basement membrane, prevents wastes/urine from seeping between epithelial cells
122
What is the unusual superficial cell feature of transitional (urinary) epithelium?
Presence of some bi-nucleated superficial cells
123
Why do the cells of transitional (urinary) epithelium obtain more oxygen?
Due to fenestrated basement membrane and decreased diffusion distance when stretched
