tissues & junctions
DESCRIPTION
Tissues & Junctions. Lecture 34 Chapter 21 - Part 1. A) TISSUES. What is tissue?. Biological tissue is a collection of similar cells and the intercellular substances surrounding them. There are four basic kinds of tissue in the body: epithelium connective tissues - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/1.jpg)
Tissues & Junctions
Lecture 34Chapter 21 - Part 1
![Page 2: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/2.jpg)
A) TISSUES
![Page 3: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/3.jpg)
What is tissue?
• Biological tissue is a collection of • similar cells • and the intercellular substances surrounding them.
• There are four basic kinds of tissue in the body: 1. epithelium
2. connective tissues– including adipose tissue, blood, bone, and cartilage
3. muscle tissue
4. nerve tissue
![Page 4: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/4.jpg)
21_02_tissues.jpg
With most multicellular organisms there are different types of cells, which are organized in to discrete groupings called tissues
![Page 5: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/5.jpg)
Plants
![Page 6: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/6.jpg)
21_05_model_plantwall.jpgPlant cells produce a primary cell wall followed by a secondary cell wall. The cell wall - which is on the outside of the plasma membrane - is made of cellulose - a polysaccharide
![Page 7: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/7.jpg)
21_06_cellulose.jpg
The cell wall will only allow the cell to grow in one direction, which is dependant upon the orientation of the fibers that were laid down during the production of the primary cell wall.
A) Here the plant tissue may only expand in a vertical direction
B) Here the plant tissue may only expand in a horizontal direction
![Page 8: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/8.jpg)
21_07_Microtubules.jpg
The celulose synthase complex, that is embedded in the plasma membrane, oozes out cellulose microfibrils
![Page 9: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/9.jpg)
Animals
![Page 10: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/10.jpg)
21_08_Extracellu_matrix.jpg
Animal cells do not use cellulose. They instead have a protein extracellular matrix of collagen, which has great tensile strength.
Animals have just 4 classes of tissue - connective, epithelial, nervous, and muscular (the last three are basically similar).
![Page 11: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/11.jpg)
21_09_Collagen_fibrils.jpg
Collagen is made of many bundles of a simple polypeptide
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
![Page 12: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/12.jpg)
21_11_elastic_skin.jpgMutations in the arrangement of these fibers may result in various abnormal outcomes.
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
![Page 13: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/13.jpg)
21_13_align_collagen.jpgFibroblasts are the cells that secrete collagen and also the ones that maintain it.
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
![Page 14: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/14.jpg)
21_14_Integrins_link.jpg
The interlinks between cells is made between collagen fibers and the actin filaments of cells using transmembrane and adaptor proteins known as integrins
How are cells held together?How are cells held together?
Fibronectin - is a linker protein
![Page 15: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/15.jpg)
21_17_epithelial_sheet.jpgEpithelial sheets and cell-cell junctions
![Page 16: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/16.jpg)
21_18_sheet_polarized.jpgMost tissue cells have a polarized structure. They rest on the basal lamina.The basal lamina is just a layer of type IV collagen, plus other molecules.
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Lung Tissue
![Page 17: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/17.jpg)
21_20_polarize_line_gut.jpgThe intestine is made of two main cell types. The absorptive cells take in nutrients and the goblet cells secrete mucus.
![Page 18: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/18.jpg)
21_21_cell_cell_junction.jpg
Animal cells are held together by a number of types of cell-cell junctions.
a) Tight Junctions - b) Adherens junction - c) desmosomes d) gap juctions - e) hemidesmosomes
![Page 19: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/19.jpg)
21_22_Tight_junctions.jpg
Tight junctions prevent the passage of solutes between cells. They also allow the cell to maintain discrete types of plasma membrane regions
![Page 20: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/20.jpg)
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Tight junctions consist of proteins, for example, claudins, occludins and junctional adhesion molecules that are anchored in the membranes of two adjacent cells and interact with each other to hold the cells together and prevent other molecules from passing between them.
![Page 21: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/21.jpg)
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
![Page 22: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/22.jpg)
21_23_Cadherin.jpgAdheren junctions and desmosome junctions are build on a common theme - they make use of transmembrane proteins that belong to the cadherin family - these molecules from adjacent cells link directly to each other.
actin or intermediate filament
![Page 23: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/23.jpg)
21_24_Adherens_junct.jpgAdheren junctions form large deposits as belts permitting adjacent cells to transmit mechanical forces
![Page 24: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/24.jpg)
21_25_tube_or_vesicle.jpg
Vital part in development
![Page 25: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/25.jpg)
21_26_Desmosomes.jpg
Desmosomes
![Page 26: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/26.jpg)
21_27_Hemidesmosome.jpg
Hemidesmosomes
![Page 27: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/27.jpg)
Gap junctions permit the free passage of small ions and small water soluble molecules to pass. However, they can be closed on demand. Plants have these too.
![Page 28: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/28.jpg)
21_30_plasmodesmata.jpg
![Page 29: Tissues & Junctions](https://reader035.vdocuments.net/reader035/viewer/2022062221/568147ad550346895db4ead1/html5/thumbnails/29.jpg)
A little perspective…
The Inner Life of a Cell - Short Version
Annotated Version