Epithelium Flashcards
(138 cards)
1
Q
With rare exceptions, what do epithelia line?
A
All body surfaces, cavities, tubes, and many glands
2
Q
What wide range of activities are epithelial interfaces involved in?
A
Selective absorption, protection, transcellular transport, detection of sensation, and secretion
3
Q
Can a single epithelial surface exhibit multiple functions?
A
Yes, a single epithelial surface may exhibit multiple functions
4
Q
What is the etymological origin of the term “epithelium”?
A
Derived from Greek: “Epi” = “on/upon”; “Thele” = “nipple”
5
Q
Epithelial layers receive nourishment via diffusion because ___?
A
Because epithelial layers are avascular
6
Q
How do epithelial tissues receive nourishment?
A
By diffusion of substances from the underlying connective tissue through the basement membrane
7
Q
Which type of epithelial structures are highly vascular?
A
Exocrine and endocrine glands
8
Q
What are epithelial clusters of cells that perform secretory functions called?
A
Exocrine and endocrine glands
9
Q
Are exocrine and endocrine epithelial cell structures vascular or avascular?
A
Highly vascular
10
Q
Epithelial cells are densely packed together with very little _________.
A
intercellular space
11
Q
Epithelial cells form continuous sheets attached to each other at many locations by ______ and ______.
A
tight junctions
12
Q
Tight junctions are formed by a pair of transmembrane proteins fused on the ______.
A
outer plasma membrane
13
Q
Adherens junctions consist of a plaque that attaches to ______.
A
microfilaments
14
Q
The plaque in adherens junctions is a ___________ located on the inside of the plasma membrane.
A
protein layer
15
Q
Desmosomes attach to the _____ of the cytoskeleton made up of _____ protein
A
microfilaments; keratin
16
Q
Hemidesmosomes resemble desmosomes on a section but differ in structure because they are made up of __________.
A
integrin
17
Q
Cadherin is replaced by what transmembrane protein in hemidesmosomes?
A
integrin
18
Q
Hemidesmosomes attach epithelial cells to the
A
basement membrane
19
Q
What kind of junction connects the cytoplasm of two cells?
A
Gap junction
20
Q
Gap junctions are made up of proteins called _________.
A
connexins
21
Q
How many connexins come together to form a connexon?
A
Six
22
Q
Functions of epithelial tissue include _______, _______, _______, and _______.
A
protection, absorption, filtration, secretion
23
Q
What tissue type is responsible for absorption in the intestines?
A
Epithelial tissue
24
Q
Where is filtration by epithelial tissue prominently seen?
A
Kidney
25
Body coverings, linings, and glandular tissue are all examples of where ______ tissue is found.
epithelial
26
Cells of epithelial tissue are ________ and held tightly together by __________.
tightly packed; cell junctions
27
________ prevent anything from passing through between epithelial cells.
Tight junctions
28
Each epithelial cell has three surfaces: _______, _______, and _______.
apical
29
The apical surface of epithelial cells typically faces the ________.
lumen or external environment
30
The basal surface of epithelial cells is attached to the ________.
basement membrane
31
The lateral surface of epithelial cells contains multiple ________ and ________ for cell-cell adhesion.
junctional complexes; adhesion molecules
32
Epithelial cells are described as forming _______ sheets with little to no intercellular space.
continuous
33
In terms of tissue classification, epithelial tissue is mainly involved in _________ and _________ processes.
protective and secretory
34
The two types of epithelial tissues are
Covering and lining epithelium, Glandular epithelium
35
The outer covering of the skin and internal organs: body cavities, blood vessels, and ducts... is made of what type of epithelial tissue?
Covering and Lining Epithelium
36
What type of epithelium lines the interior of respiratory, digestive, urinary, and reproductive organs and parts of sense organs?
Covering and Lining Epithelium
37
The secreting portion of glands is made up of what type of epithelial tissue?
Glandular Epithelium
38
The exposed surface of epithelial tissue is referred to as the ______.
Apical Surface
39
Epithelial tissue is separated from underlying tissues by what structure?
Basement membrane
40
Name the two main components of the basement membrane.
Basal lamina and Reticular lamina
41
The basal lamina is made up of what two subcomponents?
Lamina lucida and Lamina densa
42
The lateral surface of epithelial tissue is bound to what?
Other epithelial cells
43
True or False: Epithelium is vascular.
44
True or False: Epithelium is innervated.
t
45
What specialized structures are found between epithelial cells?
Junctional complexes
46
Epithelial tissue contains a ______ amount of intercellular substance.
Small
47
Cells of epithelium form ______ or more layers.
One
48
Epithelial tissues cover or line all ______ and ______ body surfaces.
Internal and external
49
Epithelial tissues are classified based on ______ and ______.
Morphology of their cells (shape) and the number of layers they are composed of
50
Epithelium with only one cell layer is called ______.
Simple Epithelium
51
Functions of simple epithelium include diffusion (lungs), osmosis, ______, ______, and ______.
Filtration (kidneys), secretion (glands), absorption (intestines)
52
Epithelium with more than one cell layer (two or more cells thick) is called ______.
Stratified Epithelium
53
Functions of stratified epithelium include ______ and ______.
Protection, secretion
54
Taller simple epithelial cells are classified as ______ epithelium.
Columnar Epithelium
55
Which epithelium appears stratified in cross-section but all cells touch the basement membrane?
Pseudostratified Epithelium
56
Pseudostratified epithelium appears stratified due to what reason?
Several nuclei at different heights
57
True or False: In pseudostratified epithelium, not all cells reach the basement membrane.
58
Flattened epithelial cells are called ______.
Squamous
59
Cube-shaped epithelial cells are called ______.
Cuboidal
60
Column-like epithelial cells are called ______.
Columnar
61
What type of epithelial cells are absorptive and contain microvilli?
Non-ciliated epithelial cells
62
What type of epithelial cells contain goblet cells that secrete mucus?
Non-ciliated epithelial cells
63
Ciliated epithelial cells function in ______.
Moving substances (e.g., in ovaries)
64
Simple epithelium type with squashed cells
Squamous
65
Endothelium and mesothelium are examples of what epithelial cell shape?
Squamous
66
Endothelium lines ____ and mesothelium lines ____
Endothelium - blood vessels; Mesothelium - serous lining of coelom
67
What simple epithelium lines blood vessels and serous membranes?
Simple squamous
68
Simple epithelium type with cubed cells
Cuboidal
69
What simple epithelium forms the walls of glands?
Simple cuboidal
70
Simple epithelium type with column-like cells
Columnar
71
The gut tube and uterine tubes are lined by what type of simple epithelium?
Simple columnar
72
In ____ epithelium, flat cells give rise to columns
Pseudostratified
73
Ciliated pseudostratified epithelium lines the ______ and helps move mucus.
Respiratory tubes
74
What simple epithelium has flat cells with disc-shaped central nuclei and sparse cytoplasm?
Simple squamous
75
The simplest epithelium, often forming membranes, is?
Simple squamous
76
Function of simple squamous epithelium
Allows passage of materials by diffusion and filtration (where protection is not important); secretes lubricating substances in serosae
77
Nuclei shapes in simple sqamous epithelium, simple cuboidal, simple columnar respectively are
Disc-shape, Spherical, Round to oval
78
Which type of epithelium is found in air sacs of lungs, kidney glomeruli, lining of heart, blood vessels, lymphatic vessels, serosae (ventral body cavity)
Simple squamous
79
Which type of epithelium forms kidney tubules, ducts and secretory portions of small glands, ovary surface
Simple cuboidal
80
Most of the digestive tract, gallbladder, secretory ducts of some glands are lined by
Non ciliated simple columnar epithelium
81
Small bronchi, uterine tubes, and some regions of the uterus are lined by
Ciliated simple columnar epithelium
82
Location of simple squamous epithelium
Air sacs of lungs, kidney glomeruli, lining of heart, blood vessels, lymphatic vessels, serosae (ventral body cavity)
83
What epithelium has single layer of cube-like cells with large, spherical central nuclei
Simple cuboidal epithelium
84
Functions of simple cuboidal epithelium
Secretion and absorption
85
Location of simple cuboidal epithelium
Forms kidney tubules, ducts and secretory portions of small glands, ovary surface
86
Simple epithelium with tall cells and round to oval nuclei
Simple columnar epithelium
87
Goblet cells are commonly found in what type of simple epithelium?
Simple columnar
88
Functions of simple columnar epithelium
Absorption; secretion of mucus, enzymes, and other substances; ciliated type propels mucus or reproductive cells
89
Non-ciliated simple columnar epithelium lines what?
Most of the digestive tract, gallbladder, secretory ducts of some glands
90
Ciliated simple columnar epithelium lines what?
Small bronchi, uterine tubes, and some regions of the uterus
91
Stratified squamous epithelium: cell shape at surface
Flattened (squamous)
92
Basal cells in stratified squamous are what shape?
Cuboidal or columnar
93
Keratinized stratified squamous epithelium contains keratin where?
Apical layer and several layers below
94
Function of stratified squamous epithelium
Protects covering where friction is common i.e protects underlying tissues from abrasion, drying out, and infection
95
Where are stratified squamous epithelium found?
Skin, mouth, esophagus, vagina
96
Location of non-keratinized stratified squamous epithelium
Moist linings of esophagus, mouth, and vagina
97
Location of keratinized stratified squamous epithelium
98
Function of stratified cuboidal epithelium
99
Location of stratified cuboidal epithelium
100
Stratified columnar epithelium: shape of surface cells and cells underneath
Columnar surface cells, cells underneath vary in size and shape
101
Functions of stratified columnar epithelium
102
Location of stratified columnar epithelium
103
Transitional epithelium is also known as ____ and it is ____?
104
Shape of transitional epithelium cells depends on?
105
Surface cells of transitional epithelium can be ______ or ______ depending on ___.
106
Basal cells of transitional epithelium are ____ or ____
Cuboidal or columnar
107
Function of transitional epithelium
108
Location of transitional epithelium
109
Pseudostratified columnar epithelium: number of layers
110
Pseudostratified columnar epithelium: appears stratified when viewed from the ____
side
111
In pseudostratified columnar epithelium, all cells reach basement membrane but not all cells reach the ______.
112
Nuclei appear at different levels in what epithelium?
113
Functions of pseudostratified columnar epithelium
114
Unciliated pseudostratified columnar epithelium is found where?
115
Ciliated pseudostratified columnar epithelium is found where?
116
Flattened surface cells, metabolically active basal layer, protective covering... describes?
117
Secretes mucus and moves it by ciliary action... function of?
118
Stretches and allows urinary organ to distend... function of?
119
Absorbs nutrients, secretes mucus and enzymes... function of?
120
Forms walls of kidney tubules and ducts, covers ovaries... characteristic of?
121
Allows passage of materials by diffusion and filtration... function of?
122
What are epithelial cells that secrete substances called?
Glands
123
Exocrine glands secrete substances onto ______ or into ______.
Body surface or body cavity
124
What type of gland has ducts and secretes onto epithelial surfaces?
Exocrine gland
125
Secretion into ducts that empty at the surface of covering and lining epithelium or onto a free surface is characteristic of?
Exocrine glands
126
Exocrine gland secretions can be released into what two areas?
Skin surface and interior of hollow organ (lumen)
127
Examples of exocrine gland secretions include ______ and ______.
Sweat and saliva
128
Give four examples of exocrine glands.
Salivary, mammary, pancreas, liver
129
Gland that secretes its product directly into the bloodstream without ducts.
Endocrine gland
130
Endocrine secretions are either stored in ______ or in ______ surrounded by secretory cells.
Secretory cells; follicles
131
Hormones secreted by endocrine glands travel to ______.
Target organs
132
What type of gland lacks ducts and releases hormones into interstitial fluid?
Endocrine gland
133
Secretion enters the interstitial fluid and diffuses into ______.
Bloodstream
134
Examples of endocrine glands include ______, ______, and ______.
Pituitary, thyroid, adrenal
135
Endocrine gland secretions include ______, ______, ______, and ______.
Amino acids, proteins, glycoproteins, steroids
136
3 glands that have both endocrine and exocrine parts
Pancreas, Ovaries, Testes
137
Stored in secretory cells or in follicles, diffuse into bloodstream to affect target organs… function of?
Endocrine gland
138
Secretes sweat, saliva, digestive enzymes; releases onto body surface or lumen… function of?
Exocrine gland
