Connective tissue Dr Samar Asker.pdf

# The Connective Tissue - Contact: Prof. Dr. Samar Asker - Department: Histology - Official email: [email protected] - Academic hours: - Sunday: 10.30 AM-1:00 PM - Monday: 9:00-11:00 AM - Image: A diagram of connective tissue. # Learning Outcomes By the end of the lecture, the st...

# The Connective Tissue - Contact: Prof. Dr. Samar Asker - Department: Histology - Official email: [email protected] - Academic hours: - Sunday: 10.30 AM-1:00 PM - Monday: 9:00-11:00 AM - Image: A diagram of connective tissue. # Learning Outcomes By the end of the lecture, the students will be able to: - Enumerate types of C.T. - Identify components of connective tissue proper (C.T) including fibers and cells & their histological structure. - Recognize the properties and location of the various types of connective tissue proper. # Body Tissues - Four major tissue types: - Epithelial tissue - Connective tissue - Muscle tissue - Nervous tissue - Image: A table of the four major tissue types. # Connective Tissue - Vascular tissue supports and connects various tissues and organs. - Origin of Connective Tissue: Mesoderm - Formed of: - Cells - Fibers - Extracellular matrix - Image: A diagram showing the layers of a germinal disc. # Types of CT - (according to matrix) - Soft: CT proper - Rubbery: cartilage - Hard: bone - Fluid: blood - Image: A diagram of the human skeletal system and blood cells. # CT PROPER ## A) CT CELLS ### 1. Loose Connective Tissue - Areolar tissue - It is present beneath the skin, serves as a support frame work for epithelium. It contains fibroblasts, macrophages and mast cells. - Image: A microscopic image of loose connective tissue. ## Fixed Cells - Mesenchymal cell (UMC) - Fibroblasts - Fixed macrophages - Fat cells - Reticular cell - Pigment cell ## Free (transient) cells - Plasma cells - Mast cells - Free macrophages - Leucocytes - Image: A table of fixed and free CT cells with a brief description and a microscopic image of each type. ### Undifferentiated Mesenchymal Cell (UMC) - LM - Branched cells - Large oval pale nucleus - Basophilic cytoplasm. - EM: Numerous ribosomes - Function: Mother cell of all types of C.T. cells. - Image: A microscopic image of a mesenchymal cell. ### Fibroblast - Origin: UMC. - LM: Branched with many long processes. - Nucleus: oval. - Cytoplasm: deeply basophilic. - EM: rich in ribosomes, rER, prominent Golgi. - Function: Synthesize C.T fibers & matrix. - Image: A microscopic image of a fibroblast. ### Adipose Cells (Fat cells) | | White (unilocular) | Brown (multilocular) | |:---|:---|:---| | Origin | UMC | - | | Function | - Storage of fat<br>- Heat insulation<br>- Support kidney & blood vessels | - Heat generation | | Shape of the cell | Large oval cell<br>Fat form one large droplet | Small oval cell<br>Fat as small droplets | | H&E | Dissolve during staining => signet ring appearance | No signet ring appearance | | Nucleus | Eccentric & flat | Central & spherical nucleus | | Stains | Sudan III (orange)<br>Sudan black----black | - | - Image: A table comparing white and brown adipose cells, with diagrams, and a humorous cartoon about fat. ### Mast Cells - Origin: UMC - Functions: Secretion of: - Heprin (anticoagulant) - Histamine: responsible for allergy. - Image: A diagram of mast cells and histamine's role in allergic reactions. ### Plasma Cells - Origin: Activated B lymphocyte. - Functions: Synthesis & secretion of antibodies. - Image: A diagram of a lymphocyte and a bacteria marked with antibodies. ### Mast Cells | | Mast Cells | Plasma Cells | |:---|:---|:---| | Cytoplasm | - Oval cell<br>- Basophilic<br>- Basophilic granules | - Oval cell <br>- Basophilic <br> -ve Golgi image | | Nucleus | Small, central, rounded | Spherical eccentric<br>With dark & light areas so have cartwheel or clock face appearance | | Stain | Metachromatically (red) by toluidine blue | - | ### Macrophages - Origin: Blood monocytes. - LM: - Large branched with pseudopodia - Pale basophilic cytoplasm - Single dark eccentric kidney shaped nucleus. - Stain: Trypan blue - Function: Phagocytosis - Image: A microscopic image of a macrophage. ## II. C.T. Fibers - 3 Types: - White collagenous F. - Yellow elastic F. - Reticular F. - Image: A diagram of connective tissue fibers. | | White collagenous F. | Yellow elastic F. | Reticular F. | |:---|:---|:---|:---| | Characters | Strong and resist stretch | Elastic, can be stretched but recoil after stretch release. | Tend to form a reticulum | | LM | Non branched fibers⇒ form wavy bundles. | Branched fibers. ⇒form fenestrated membranes. | Very thin fibers ⇒ form a delicate network. | | H&E | Red | Pink | Not Stained | | Van Gieson | Red | Yellow | - | | | Mallory → blue | Verhoef's → Black | Silver → black | - Image: A table comparing fibers including a microscopic image of each. # Diseases Associated With Collagen - Ehlers-Danlos syndrome - Image: A person demonstrates hyper-extensible fingers and wrists - Osteoperosis - Image: A woman helping an elderly woman with osteoporosis. # CT PROPER Summary Table | | Description | Stains | Function/Misc. | |:---|:---|:---|:---| | UMC | Mother cell of all types of C.T. cells. | - | - | Fibroblast | The most common cell in CT. | - | - | | Macrophage | Origin: monocyte.<br>LM: Large branched with pseudopodia. <br>Pale basophilic cytoplasm<br>Single dark eccentric kidney shaped nucleus | Trypan blue | Phagocytosis | | Fat cells | Oval | H&E signet ring<br>Sudan III (orange)<br>Sudan black----black| - | | Mast cells | - | Metachromatically (red) by toluidine blue | Alergy | | Plasma cell | Activated B lymphocyte. | -ve Golgi image | AB | | White collagenous | Resist stretch | Van Gieson → red<br>Mallory → blue | - | | Yellow elastic F. | Stretched but recoil | Van Gieson → yellow<br>Verhoef's → Black. | - | | Reticular F. | Reticulum | Silver → black | - | # Types Of Connective Tissue Proper - Loose connective tissue - White fibrous connective tissue - Yellow elastic connective tissue - Adipose connective tissue - Mucoid connective tissue - Reticular connective tissue - Image: Diagram of the types of connective tissues. ### Loose Areolar C.T. - The commonest type of C.T. proper in the body. - Function: Support epithelium, BLV & nerves. - Image: Diagram of loose areolar connective tissue. ### Yellow Elastic C.T. - Formed of: Elastic fibers separated by fibroblasts - Sites: 1. Large arteries ### White Fibrous C.T. - Structure: Parallel collagen bundles with fibroblasts in-between. - Regular - Image: Microscopic image of regular white fibrous connective tissue. - Irregular - Image: Microscopic image of irregular white fibrous connective tissue. ### Adipose Connective Tissue | | White (unilocular) | Brown (multilocular) | |:---|:---|:---| | Sites | - under the skin <br>- around the kidney &blv | - In embryo.<br>❖Interscapular region.<br> - In adults:<br>❖Around thoracic aorta | ### Reticular C.T. - Lymphatic organs as spleen and LN - Bone marrow & liver. - Image: Microscopic image of reticular connective tissue. ### Mucoid C.T. - Site: Umbilical cord. - Image: Microscopic image of mucoid connective tissue. # CT PROPER Flowchart - Image: Diagram of the relationships between the different cells and fibers of connective tissues. # It’s MCQ Time 1. **Cartwheel appearance of nucleus is a feature of:** 1) Macrophage 2) Mast cell 3) Plasma cell 4) Pigment cell 2. **What is the most common type of connective tissue cells?** 1) Mast cell 2) Plasma cell 3) Fibroblast 4) Mesenchymal cell 5) Reticular cell 3. **Metachromatic stain is used for:** 1) Mast cells 2) Adipocytes 3) Macrophages 4) Mesenchymal cells 5) Fibroblast # Thank You - Image: "thank you" spelled with wooden blocks.