Tissues, Part 2 - Epithelial Tissue: Crash Course A&P #3
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Date: 2022-04-04
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Comments and reviews: 8
Sudharsan
Notes:
3. Epithelial tissues-
Two kinds: PROPER/PRIMARY EPITHELIUM (covers & lines the outer and inner body) and GLANDULAR EPITHELIUM (forms the glands and secretes hormones & other substances. -
Epithelial tissues are Avascular (not associated with or supplied by blood vessels. They instead rely on the blood supply to the Connective tissues around them for the materials they need. -
Criteria for classification of Epithelial cells: Shape of the individual cells and the number of layers that they form in. -
THREE BASIC SHAPES: -
SQUAMOUS cells (flattened shape and flat nucleus, fast absorption and diffusion, making thin membranes. -
CUBOIDAL cells (spherical nucleus, cuboidal cell shape, absorb nutrients and produce secretions like sweat. -
COLUMNAR cells (Elliptical nucleus, column shaped cell with hexagonal cross-section, tall, thick & cushion underlying tissues, absorb nutrients and produce secretions. -
Usually the form (shape and layering) of the epithelial cell is related to it's function/purpose. -
Producing cells take a lot of time, energy and raw materials. So in places where we lose a lot of cells (like outer skin or mouth) we have squamous cells because they are biologically cheaper. -
TYPES OF LAYERING: -
SIMPLE EPITHELIUM: one layer of cells. -
STRATIFIED: Multiple layers set up on top of each other, like bricks. -
PSEUDOSTRATIFIED: Mostly one layer but formed with cells of different shapes and sizes. The cells nuclei can be at a lot of different levels (i. e they don't lie on the same plane- different heights. So it looks like multi layered. -
NAMING OF A EPITHELIAL TISSUE: -
First name: Number of layers. -
Last name: Shape of its cells. -
Example: Simple squamous epithelium. -
All Epithelial cells are POLAR i. e they have distinct sides. -
The boundaries of many of these cells are 'Selectively Permeable'(Allowing for some level of absorption, filtration and excretion of substances. Example: tissues lining the small intestine allows absorption of nutrients through diffusion and active transport. This is what makes possible all interaction we have with the world since Epithelial cells line both the insides and outside of the body (U Tube). -
GLANDULAR EPITHELIUM forms two different types of glands: ENDOCRINE glands (secrete hormones directly into the blood stream or to nearby cells) and EXOCRINE glands (secrete their juices into tubes or ducts that lead to the outside of the body.
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Notes:
3. Epithelial tissues-
Two kinds: PROPER/PRIMARY EPITHELIUM (covers & lines the outer and inner body) and GLANDULAR EPITHELIUM (forms the glands and secretes hormones & other substances. -
Epithelial tissues are Avascular (not associated with or supplied by blood vessels. They instead rely on the blood supply to the Connective tissues around them for the materials they need. -
Criteria for classification of Epithelial cells: Shape of the individual cells and the number of layers that they form in. -
THREE BASIC SHAPES: -
SQUAMOUS cells (flattened shape and flat nucleus, fast absorption and diffusion, making thin membranes. -
CUBOIDAL cells (spherical nucleus, cuboidal cell shape, absorb nutrients and produce secretions like sweat. -
COLUMNAR cells (Elliptical nucleus, column shaped cell with hexagonal cross-section, tall, thick & cushion underlying tissues, absorb nutrients and produce secretions. -
Usually the form (shape and layering) of the epithelial cell is related to it's function/purpose. -
Producing cells take a lot of time, energy and raw materials. So in places where we lose a lot of cells (like outer skin or mouth) we have squamous cells because they are biologically cheaper. -
TYPES OF LAYERING: -
SIMPLE EPITHELIUM: one layer of cells. -
STRATIFIED: Multiple layers set up on top of each other, like bricks. -
PSEUDOSTRATIFIED: Mostly one layer but formed with cells of different shapes and sizes. The cells nuclei can be at a lot of different levels (i. e they don't lie on the same plane- different heights. So it looks like multi layered. -
NAMING OF A EPITHELIAL TISSUE: -
First name: Number of layers. -
Last name: Shape of its cells. -
Example: Simple squamous epithelium. -
All Epithelial cells are POLAR i. e they have distinct sides. -
The boundaries of many of these cells are 'Selectively Permeable'(Allowing for some level of absorption, filtration and excretion of substances. Example: tissues lining the small intestine allows absorption of nutrients through diffusion and active transport. This is what makes possible all interaction we have with the world since Epithelial cells line both the insides and outside of the body (U Tube). -
GLANDULAR EPITHELIUM forms two different types of glands: ENDOCRINE glands (secrete hormones directly into the blood stream or to nearby cells) and EXOCRINE glands (secrete their juices into tubes or ducts that lead to the outside of the body.
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Anthony
Epithelial tissue - the tissue that lines, covers, and generally organizes your body-
Proper Epithelium - covers and lines your outer and inner body; creates skin, lines your body cavities-
Glandular Epithelium - forms your glands and secretes hormones and other substances-
The epithelium does all this to protect your deeper layers of tissue from injury or infection. All epithelial tissues are avascular - not associated with or supplied by blood vessels. They instead rely on the blood of the connective tissues around them. -
Shape and layering - The shape of the individual cells and the number of layers that they form in. Three basic shapes, squamous, cuboidal, and columnar. -
Squamous - flat, like a fish scale; fast absorption and diffusion, making thin membranes-
Cuboidal - absorb nutrients, produce secretions like sweat-
Columnar - absorb nutrients, produce secretions-
The shape of each epithelial cell correlates with its function. -
Simple epithelium - one layer of cells-
Stratified epithelium - multiple layers set on top of each other, like bricks-
Pseudostratified epithelium - mostly just one layer; cells with different shapes and sizes-
The tissue-s first name is its number of layers, and its last name is the shape of its cells. -
Epithelial tissue regenerates very quickly. -
Epithelial cells are polar - they have distinct sides. -
Apical side: /\-
Basal side: \/-
The sides are attached with a basement membrane. -
Selectively permeable - allowing for some level of absorption, filtration, and excretion of substances-
Endocrine glands - secrete hormones right into your bloodstream or to nearby cells-
Exocrine glands - secrete their juices into tubes or ducts that lead to the outside of the body
reply
Epithelial tissue - the tissue that lines, covers, and generally organizes your body-
Proper Epithelium - covers and lines your outer and inner body; creates skin, lines your body cavities-
Glandular Epithelium - forms your glands and secretes hormones and other substances-
The epithelium does all this to protect your deeper layers of tissue from injury or infection. All epithelial tissues are avascular - not associated with or supplied by blood vessels. They instead rely on the blood of the connective tissues around them. -
Shape and layering - The shape of the individual cells and the number of layers that they form in. Three basic shapes, squamous, cuboidal, and columnar. -
Squamous - flat, like a fish scale; fast absorption and diffusion, making thin membranes-
Cuboidal - absorb nutrients, produce secretions like sweat-
Columnar - absorb nutrients, produce secretions-
The shape of each epithelial cell correlates with its function. -
Simple epithelium - one layer of cells-
Stratified epithelium - multiple layers set on top of each other, like bricks-
Pseudostratified epithelium - mostly just one layer; cells with different shapes and sizes-
The tissue-s first name is its number of layers, and its last name is the shape of its cells. -
Epithelial tissue regenerates very quickly. -
Epithelial cells are polar - they have distinct sides. -
Apical side: /\-
Basal side: \/-
The sides are attached with a basement membrane. -
Selectively permeable - allowing for some level of absorption, filtration, and excretion of substances-
Endocrine glands - secrete hormones right into your bloodstream or to nearby cells-
Exocrine glands - secrete their juices into tubes or ducts that lead to the outside of the body
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Sam
Careful when you're looking at slides trying to classify these epithelial tissues. The cartoons make it look like stratified epithelium all have the same shape. This certainly is not the case. The stem cells producing squamous or columnar cells are often cuboidal in shape. To identify stratified epithelium always look at the surface (apical) side of the tissue.
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Careful when you're looking at slides trying to classify these epithelial tissues. The cartoons make it look like stratified epithelium all have the same shape. This certainly is not the case. The stem cells producing squamous or columnar cells are often cuboidal in shape. To identify stratified epithelium always look at the surface (apical) side of the tissue.
reply
arcangeljp
About to enlist into the Air Force and will be taking on the Aerospace Medical position. I failed A&P about 15 years ago and wanted to get ahead of my studies before I ship out to base. This is SUPER helpful and actually interesting. THANK YOU. This makes me feel confident that I will succeed.
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About to enlist into the Air Force and will be taking on the Aerospace Medical position. I failed A&P about 15 years ago and wanted to get ahead of my studies before I ship out to base. This is SUPER helpful and actually interesting. THANK YOU. This makes me feel confident that I will succeed.
reply
Valkyrie_on_wheels
You guys should make study apps. I'd be willing to pay for one with the graphics and everything I'm sure you do. Your videos helped me in LPN school and now I'm using them to refresh for RN school. Thank you so much!
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You guys should make study apps. I'd be willing to pay for one with the graphics and everything I'm sure you do. Your videos helped me in LPN school and now I'm using them to refresh for RN school. Thank you so much!
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Lei
Me after two episodes: (positions, nervous and muscle tissue) mastered it a bit (except positions)
Me after Hank says -it depends on shapes-:
nooooooooooo
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Me after two episodes: (positions, nervous and muscle tissue) mastered it a bit (except positions)
Me after Hank says -it depends on shapes-:
nooooooooooo
reply
Dr.
And here I am to bring this playlist into limelight again. Sharing the playlist with my medical college groups. May they all be blessed with this.
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And here I am to bring this playlist into limelight again. Sharing the playlist with my medical college groups. May they all be blessed with this.
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john
umm thanks I found this and i dont understand anything at all but i will gonna through with it because I aim to becomee a surgeonn Thankiesss
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umm thanks I found this and i dont understand anything at all but i will gonna through with it because I aim to becomee a surgeonn Thankiesss
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