Session 5.2a - Lecture 1 - Epithelial Tissues and Glands Flashcards
Slides 1 - 17
1
Q
What are the glands connected with epithelial tissues?
A
Exocrine glands
2
Q
What are the tissues connected with exocrine glands?
A
Epithelial tissues
3
Q
In a histology course, we’d normally start with epithelial tissues. Why?
A
Not entirely sure, but mainly bc we’re encompassed by epithelium, so it’s a good place to start when we’re thinking about the tissues of the body.
4
Q
Where does epithelium lie?
A
- On our outermost surface
- Lines every one of our internal body cavities.
5
Q
What cell type are we encompassed by?
A
Epithelial tissue
6
Q
What cell type is on our outermost surface?
A
Epithelium
7
Q
What lines every one of our internal body cavities?
A
Epithelium
8
Q
Name two types of epithelial membranes.
A
- Mucous membranes
- Serous membranes
9
Q
What do mucous and serous membranes have in common?
A
They are types of epithelial membrane.
10
Q
What is mucosae?
A
A mucous membrane (plural)
11
Q
What is a mucous membrane otherwise know as?
A
Mucosae (plural)
12
Q
What is serosae?
A
A serous membrane (plural)
13
Q
What is a serous membrane otherwise know as?
A
Serosae (plural)
14
Q
What is the singular form of mucosae?
A
Mucosa
15
Q
What is mucosa?
A
The singular form of a mucous membrane
16
Q
What is the singular form of serosae?
A
Serosa
17
Q
What is serosa?
A
The singular form of a serous membrane
18
Q
What are mucous membranes?
A
They line certain internal tubes which open to the exterior.
19
Q
What is the name for that which lines certain internal tubes which open to the exterior?
A
Mucous membranes
20
Q
Give 3 examples of internal tubes which open to the exterior, thus have mucous membranes.
A
i.e. the alimentary tract
the respiratory tract
the urinary tract
21
Q
Why are these mucosae called mucous membranes?
A
These mucosae are called mucous membranes because they bear mucus-secreting cells to varying degrees
22
Q
What is the spelling for the noun and adjective of mucous?
A
Noun - Mucus (thing)
Adjective - Mucous (description)
23
Q
What is the noun of mucous?
A
Mucus, it is the thing
24
Q
What is the adjective of mucous?
A
Mucous, with an O.
25
What does a mucous membrane consist of?
A MUCOUS MEMBRANE consists of:
• an epithelium (type depends on site) lining the lumen of a tube.
• an adjacent layer of connective tissue often referred to as the
lamina propria (literally ‘one’s own layer’).
• in the alimentary tract, a third layer consisting of smooth muscle
cells, referred to as the muscularis mucosae.
26
An epithelium, lamina propria and (in the case of the alimentary tract), the muscularis mucosae make up the what?
Mucous membrane
27
Describe the epithelium of the mucous membrane.
- The type depends on site
| - Lines the lumen of a tube
28
What is the epithelial type of the mucous membrane?
Type depends on site
29
Where does the epithelium of a mucous membrane lay?
It lines the lumen of a tube
30
What is the lamina propria?
An adjacent layer of connective tissue
31
What is the adjacent layer of connective tissue in the mucous membrane called?
The lamina propria
32
What is lamina propria Latin for?
"one's own layer"
33
What is the Latin for "one's own layer"?
Lamina propria
34
Mucous membranes consist of an epithelium and the lamina propria. Sometimes there is a third layer. Where is this found?
The alimentary tract
35
What is the alimentary tract?
Alimentary (adj.) - relating to nourishment or sustenance.
i.e. digestive tract
36
What is the third layer of mucous membrane found in the alimentary tract called?
Muscularis mucosae
37
What is muscularis mucosae?
The third layer found in the mucous membrane consisting of a very THIN layer of smooth muscle cells (not the big thick layers, but a very thin layer)
38
What type of cells does muscularis mucosae consist of?
Smooth muscle cells
39
Describe the smooth muscle cells found in muscularis mucosae.
Very thin layer
40
Fig. 4
Caption this image.
MUCOSA OF GUT WALL lines the lumen
41
Fig. 4
Label this image.
- Muscularis mucosae
- Lamina propria
- Epithelium
} MUCOSA
- (green) Aggregations of lymphocytes (Peyer's patches) are often present in the lamina propria
- Mucosal gland
42
Fig. 4
What tract is this picture showing?
The alimentary tract
43
Fig. 4
How can you tell which muscle layer is muscularis mucosae?
- THIN layer of muscle (not this thicker layer of muscle out here that moves food along the alimentary tract)
- Next to lamina propria
44
Fig. 4
Label the muscle that moves food along the alimentary tract
The thick layer of muscle on the outside
45
Fig. 4
What is this thick layer of muscle on the outside?
The muscle that moves food along the alimentary tract - NOT the lamina propria
46
Fig. 4
How can you tell which layer is the lamina propria?
- White tissue
- NOT thick submucosa
- Lies in the mucosa itself
47
Fig. 4
What is the thicker white layer called?
Submucosa
| i.e. under the mucosa
48
Fig. 4
Label the submucosa.
Thick white layer (not the lamina propria) - not in the mucosa.
49
Fig. 4
Which layer lies right next to the lumen of the tube?
The epithelium
50
What are the 3 layers that make up the mucosa?
- Epithelium
- Lamina propria
- Muscularis mucosae
51
Where are mucosal glands of the alimentary tract found?
In the lamina propria
52
What glands do we find in the lamina propria?
Mucosal glands
53
What are aggregations of lymphocytes in the lamina propria of the small intestine called?
Peyer's patches (Fig. 4)
54
What are Peyer's patches?
Aggregations of lymphocytes present in the lamina propria of the ileum of the small intestine. (Fig. 4)
55
What can we find in the lamina propria?
- Mucosal gland
| - Aggregations of lymphocytes
56
Fig. 4
Where specifically is the lumen?
- Alimentary tract/gut wall
| - -> Peyer's patches = ileum of small intestine
57
Draw a cross section of the lumen and mucosa of the gut wall (4 marks).
See Fig. 4
- Muscularis mucosae (thin)
- Lamina propria (within mucosa)
- Epithelium
} MUCOSA
- (green) Aggregations of lymphocytes (Peyer's patches) are often present in the lamina propria
- Mucosal gland
1 mark - layers in the right place
1 - muscular mucosae is thin
1 - mucosal gland and Peyer's patches
1 - submucosa and outer muscle for moving food correctly labelled
58
What are serous membranes?
SEROUS MEMBRANES are thin, two-part membranes which line certain closed body cavities (spaces that don’t open to the exterior).
59
What are thin, two-part membranes which line certain closed body cavities called?
Serous membranes
60
What are closed body cavities?
Spaces that don't open to the exterior.
61
What do serous membranes envelop?
The viscera
62
What thin, two-part membrane envelops the viscera?
Serous membranes
63
Name 3 serous membranes.
- peritoneum
- pleural sac
- pericardial sac
64
What is the peritoneum?
Serous membrane which lines our abdomen and envelops many abdominal organs.
65
What is the function of the peritoneum?
That’s a serous membrane, that means all our internal viscera can move around fairly smoothly without getting caught on themselves.
66
What is the serous membrane which envelops the abdomen?
Peritoneum
67
What structure allows the internal viscera to move smoothly without friction?
Serous membranes
68
What do the pleural sacs envelop?
The lungs
69
What serous membrane envelops the lungs?
Pleural sacs
70
What is the function of the pleural sac?
We breathe in and out with minimal friction bc of the serous membranes forming the pleural sac, each lung lying in a pleural sac.
71
Why can we breathe in and out with minimal friction?
Each lung lies in a pleural sac - a serous membrane.
72
What does the pericardial sac envelop?
The heart
73
What serous membrane envelops the heart?
Pericardial sac
74
What is the function of the pericardial sac?
Our heart is beating with minimal friction bc it’s beating within 2 serous membranes lying right next to each other with some lubricating fluid between the pericardial sac.
75
How does the heart beat with minimal friction?
Because it's lying within the pericardial sac - 2 serous membranes with some lubricating fluid inbetween.
76
What do serous membranes secrete?
Lubricating fluid
77
Which type of membrane secretes lubricating fluid?
Serous membrane (serosae)
78
What is the function of the lubricating fluid secreted by the serous membrane?
Promotes relatively friction-free movement of the structures they surround
79
What promotes relatively friction-free movement of the structures they surround?
Lubricating fluid secreted by serous membranes.
80
What does a serous membrane consist of?
• a simple squamous epithelium (mesothelium) which secretes a
watery lubricating fluid.
• a thin layer of connective tissue which attaches the epithelium
to adjacent tissues (also carries blood vessels and nerves).
81
A simple squamous epithelium and thin layer of connective tissue which attaches epithelium to adjacent tissues is known as what?
Serous membrane
82
What type of epithelium is found in serous membranes?
Simple squamous epithelium
83
What do we call the simple squamous epithelium found in serous membranes?
Mesothelium
84
What is the mesothelium?
Simple squamous epithelium found in serous membranes.
85
What does the mesothelium do?
Secrete a watery lubricating fluid.
86
What secretes a watery lubricating fluid in the serous membrane?
The mesothelium
87
What is a complication of asbestosis?
Mesothelioma
88
What causes mesothelioma?
Asbestosis
89
What is asbestosis?
Asbestosis is a serious long-term lung condition caused by prolonged exposure to asbestos
90
Long-term lung condition caused by prolonged exposure to asbestos is called what?
Asbestosis
91
What is mesothelioma?
A cancer of the simple squamous epithelium (mesothelium) of serous membranes.
92
What is a cancer of the simple squamous epithelium of serous membranes known as?
Simple squamous epithelium = mesothelium
Mesothelioma
93
In addition to the mesothelium (simple squamous), what does the serous membrane contain?
A thin layer of connective tissue which attaches the epithelium to adjacent tissues (also carries blood vessels and nerves)
94
A thin layer of connective tissue which attaches the epithelium to adjacent tissues (also carries blood vessels and nerves) is found in which type of membrane?
Serous membrane
95
Describe mucous and serous membranes.
A MUCOUS MEMBRANE consists of:
• an epithelium (type depends on site) lining the lumen of a tube.
• an adjacent layer of connective tissue often referred to as the lamina propria (literally ‘one’s own layer’).
• in the alimentary tract, a third layer consisting of smooth muscle cells, referred to as the muscularis mucosae.
A SEROUS MEMBRANE consists of:
• a simple squamous epithelium (mesothelium) which secretes a watery lubricating fluid.
• a thin layer of connective tissue which attaches the epithelium to adjacent tissues (also carries blood vessels and nerves).
96
When do the heart, lungs and gut develop next to a bag-like cavity into which they invaginate/intrude?
During embryonic development
97
What happens to the heart, lungs and gut during embryonic development?
They develop next to a bag-like cavity into which they invaginate/intrude
98
Which organs, during embryonic development, develop next to a bag-like cavity into which they invaginate/intrude?
Heart, lungs, gut
99
What is the bag-like cavity surrounding the heart, lungs and gut called?
Serous membrane
100
Explain the relationship of the serous membrane to the heart, lungs and gut.
They are surrounded by it, but do NOT lie within the serous cavity itself
101
Explain the relationship of the serous cavity to the heart, lungs and gut.
They do NOT lie within the serous cavity itself (but are surrounded by the serous MEMBRANE)
102
Fig. 7
Label the image (as an analogy to serous membranes).
- Outer balloon wall (equivalent to PARIETAL serosa).
- Inner balloon wall (equivalent to VISCERAL serosa).
- Air (equivalent to lubricating fluid of the serous cavity).
103
Draw an image depicting serous membranes.
See Fig. 7 (accept analogy)
- Outer balloon wall (equivalent to PARIETAL serosa).
- Inner balloon wall (equivalent to VISCERAL serosa).
- Air (equivalent to lubricating fluid of the serous cavity).
104
Fig. 7
Explain what the balloon and fist represent.
Balloon represents the lining (serosa) of a body cavity.
| Fist represents an organ like the heart, lung, or gut.
105
What is the analogy of serous membranes?
A bit like a chi fist into a poorly deflated balloon.
106
What do the heart, lung and many visceral organs do during embryological development?
Develop into a sac and intrude into it.
107
Which organs develop into a sac and intrude into it?
Heart, lungs and many visceral organs.
108
What does the balloon represent in the serosal membrane analogy?
The lining (serosa) of a body cavity.
109
What is akin to the lining (serosa) of a body cavity in serous membrane analogies?
Balloon
110
What does the first represent in the serosal membrane analogy?
Fist represents an organ like the heart, lung or gut
111
How are organs like the heart, lung or gut represented in serous membrane analogies?
Like a clenched fish (in a poorly deflated balloon).
112
What are the two serosal membranes?
- Parietal
| - Visceral
113
What is the outer serosal membrane called?
Parietal serosa
114
What is the inner serosal membrane called?
Visceral serosa
115
Parietal serosa is the _____ serosal membrane.
Outer
116
Visceral serosa is the _____ serosal membrane.
Inner
117
What is in between the two serosal membranes?
Lubricating fluid
118
Where is lubricating fluid of the serous cavity found?
In between the two serosal membranes (parietal [outer] and visceral [inner]).
119
What is the pericardium?
The membrane enclosing the heart, consisting of an outer fibrous layer and an inner double layer of serous membrane (parietal and visceral serosa).
120
What is the membrane enclosing the heart, consisting of an outer fibrous layer and an inner double layer of serous membrane called?
Pericardium
121
What does the heart lie in?
The pericardium - like a balloon into which it’s protruded or invaginated during embryological development
122
The pericardium contains ...
The heart
123
Where does the visceral serosa of the pericardium lie?
Right next to the heart muscle
124
What part of the pericardium lies right next to the heart muscle?
Visceral serosa
125
Where does the parietal serosa of the pericardium lie?
On the outer edge of the, sort of lying next to, the left lung
126
What part of the pericardium lies on the outer edge of the, sort of lying next to, the left lung?
Parietal serosa
127
Where is the lubricating fluid in serous membranes?
In between the parietal and visceral serosa
128
What lies between the parietal and visceral serosa?
Lubricating fluid
129
What is the function of the lubricating fluid in the pericardium?
Allows the heart to beat with minimal friction.
130
What allows the heart to beat with minimal friction?
Lubricating fluid
131
Fig. 8
Label and caption the image.
PERICARDIAL SAC
- Visceral serosa of pericardium.
- Parietal serosa of pericardium.
132
Draw the pericardial sac outline.
See Fig. 8
| PERICARDIAL SAC
- Visceral serosa of pericardium.
- Parietal serosa of pericardium.
Lubricating fluid in between
133
Fig. 8
Indicate where the lubricating fluid lies.
In between the two membranes (parietal and visceral) of the serosa
134
Describe where the pleurae of the lungs lie from superficial to deep.
- Rib
- Parietal pleura
- Lubricating fluid
- Visceral pleura
- Lungs
135
Where is the visceral pleura of the lungs?
REALLY closely attached, just microns away from the alveoli
136
What is attached to the lungs, just microns away from the alveoli?
Visceral pleura
137
What is the pleural cavity structure?
- Parietal pleura
- Lubricating fluid
- Visceral pleura
138
Where is the parietal pleura of the lungs?
Right next to the rib and intercostal muscles
139
Which pleura lies right next to the rib and intercostal muscles?
Parietal
140
Which pleura lies right next to the lungs?
Visceral
141
Describe the location of the parietal and visceral pleura.
Parietal - next to the rib and intercostal muscles
Visceral - next to the lungs
142
What is the function of the lubricating fluid in the lungs?
So the lungs can move independently to the ribs
143
What allows the lungs to move independently to the ribs?
The lubricating fluid
144
Fig. 9 (top)
Label and caption the image.
PLEURAE OF LUNGS
- Visceral pleura
- Rib
- Parietal pleura
145
Fig. 9 (bottom)
Label and caption the image.
LEFT LUNG which has been taken out and twisted sideways
- Lung is 'shiny' because covered by moist pleura (visceral)
- Impression of aorta
- Impression of heart
146
Draw the pleurae of the lungs.
See Fig. 9 (top)
PLEURAE OF LUNGS
- Visceral pleura
- Rib
- Parietal pleura
- Lungs (alveoli)
147
Draw the lung from prosection.
See Fig. 9 (bottom)
LEFT LUNG which has been taken out and twisted sideways
- Lung is 'shiny' because covered by moist pleura (visceral)
- Impression of aorta
- Impression of heart
148
What is the peritoneum?
The serous membrane that forms the lining of the abdominal cavity. It has many of the viscthat will have protruded into it.
149
What is the serous membrane that covers the abdominal cavity called?
The peritoneum
150
Name some organs the peritoneum covers.
- Small intestine (e.g. duodenum, ileum)
- Stomach
- Transverse colon
- Liver
151
Describe the relationship of some of the abdominal organs to the serosa?
- Stomach surrounded by serosa
- Transverse colon completely surrounded by serosa
- Bladder has serosa on one side but not completely surrounded by it
152
Fig. 10
Label and caption the image.
THE PERITONEUM
- Parietal peritoneum
- Visceral peritoneum
- Stomach
- Transverse colon
- Duodenum
- Ileum
Sagittal section
153
Draw a sagittal section of the peritoneum and the organs it covered.
See Fig. 10
THE PERITONEUM
- Parietal peritoneum
- Visceral peritoneum
- Stomach (fully covered by it)
- Transverse colon (fully covered by it)
- Duodenum
- Ileum
- Bladder (serosa only on one side)
154
What are epithelia?
Sheets of contiguous cells, of varied embryonic origin, that cover the external surface of the body and line internal surfaces
155
What are the sheets of contiguous cells, of varied embryonic origin, that cover the external surface of the body and line internal surfaces?
Epithelia
156
What embryonic origin are epithelia derived from?
Varied
157
How are the cells arranged in epithelia?
Sheets of contiguous cells
158
What do epithelia cover and line?
The external surface of the body (and line the internal surface)
159
What do epithelia line?
Internal surface (but cover the external surface)
160
Surfaces with epithelial linings can be?
- Exterior surface
- Interior spaces opening to exterior
- Interior spaces which do not open to the exterior
161
Give an example of an epithelium that is an exterior surface?
Skin
162
Give examples of epithelia that are interior spaces opening to exterior?
- gastrointestinal tract
- respiratory tract
- genitourinary tract
163
Give examples of epithelia that are interior spaces which do not open to the exterior?
- pericardial sac
- pleural sacs
- peritoneum
- blood vessels
- lymphatic vessels
164
What type of epithelia is the skin?
(The epidermis is) stratified squamous keratinised epithelium
165
What part of the skin is stratified squamous keratinised epithelium?
Epidermis
166
As well as our pericardial sac, pleural sac and peritoneum, what other interior space is lined by epithelia, that is not open to the exterior?
Blood vessels
| Lymphatic vessels
167
List the surfaces with epithelial linings.
Exterior surface:
skin
Interior spaces opening to exterior:
gastrointestinal tract
respiratory tract
genitourinary tract
```
Interior spaces which do not open to the exterior:
pericardial sac
pleural sacs
peritoneum
blood vessels
lymphatic vessels
```
168
What terms can we use to describe epithelia?
- simple
- stratified/compound
- pseudostratified
- squamous
- cuboidal
- columnar
- transitional
169
How can we categorise eptithelia?
- Simple
| - Stratified/compound
170
What does SIMPLE epithelia mean?
One cell layer thick
171
What does STRATIFIED/COMPOUND epithelia mean?
More than one cell layer thick (i.e., two or more)
172
How can we classify simple epithelia?
SQUAMOUS
CUBOIDAL
COLUMNAR
PSEUDOSTRATIFIED
173
How can we classify stratified/compound epithelia?
SQUAMOUS
CUBOIDAL
COLUMNAR
TRANSITIONAL
174
What is squamous epithelia?
Flattened
175
What is cuboidal epithelia?
Approximately square in cross-section
176
What is columnar epithelia?
Cells that are higher than they are wide
177
What is pseudostratified epithelia?
Cells that have an appearance of being more than one cell layer thick, but are not (hence, by definition, can only be found in simple epithelia)
178
What is transitional epithelia?
Epithelia that changes. (Can only find this in stratified epithelia).
179
Explain how we classify epithelia.
```
SIMPLE (one cell layer thick)
SQUAMOUS - flattened
CUBOIDAL - sq. in cross section
COLUMNAR - higher than wide
PSEUDOSTRATIFIED - looks like >1 cell layer
```
```
STRATIFIED / COMPOUND
(more than one cell layer thick)
SQUAMOUS
CUBOIDAL
COLUMNAR (as above)
TRANSITIONAL - changes
```
180
What does simple squamous epithelium sit on?
Basement membrane
181
What does every epithelium sit on?
Basement membrane
182
What is the basement membrane?
A very thin, flexible, acellular layer that every epithelium sits on. Subtending connective tissue lies underneath.
183
What lies on the epithelial side of the basement membrane?
Exterior (if it's the skin)
or
Lumen (of gut/blood vessel etc.)
184
Where does the exterior (skin) or lumen (gut/blood vessel etc.) sit on?
The opposite side to the epithelia attached to the basement membrane.
185
Describe the appearance of simple squamous epithelia.
- Really thin
- Flattened
- Nuclei often thicker than cell cytoplasm itself
- Looks like a fried egg in a frying pan
186
What is the thin acellular layer that epithelial cells sit on called?
Basement membrane
187
Which epithelial type appears very thin?
Simple squamous
188
Which epithelial type appears flattened?
Simple squamous
189
In which epithelia does the nuclei often thicker than cell cytoplasm itself?
Simple squamous
190
Which epithelia looks like a fried egg in a frying pan?
Simple squamous
191
Fig. 15
Label this image
- Simple squamous epithelium (note it looks thin, flat, nuclei thicker than cell cytoplasm like a fried egg)
- Basement membrane (drawn much thicker than it actually is)
192
Draw an image of simple squamous epithelium.
See Fig. 15
- Simple squamous epithelium (note it looks thin, flat, nuclei thicker than cell cytoplasm like a fried egg)
- Basement membrane (drawn much thicker than it actually is)
193
Why do we have different types of epithelium?
To do with their function.
194
What is the position, structure and function of the basement membrane?
Position: lies between epithelial cells and subtending connective tissue (underneath)
Structure: thin, flexible, acellular layer
Function: - serves as a strong flexible layer to which epithelial cells adhere
- serves as a cellular and molecular filter
- degree to which malignant cells penetrate BM is highly relevant to prognosis
195
Where does the basement membrane sit?
Between epithelial cells and subtending connective tissue.
196
What is the function of the basement membrane?
- To serve as a strong flexible layer to which epithelial cells adhere
- Also serves as a cellular/molecular filter
197
Why is the basement membrane important clinically?
The degree to which malignant cells penetrate basement membrane (where it can breakthrough to subtending CT) is highly relevant to prognosis
198
What is on the other side of the basement membrane, other than epithelial cells?
Subtending connective tissue (always some CT underneath)
199
Give an example of where an epithelium can become malignant?
E.g. malignant melanoma
200
What is the difference between basement membrane and basal lamina?
BM - thin acellular layer on which epithelia sit
BL - part of basement membrane
NB: the two are used inconsistently in the literature - use basement membrane
