In the lung, alveolar macrophages dust cells are found easily in the air spaces where these cells have either ingested carbon particles or erythrocytes. Some may appear as vacuolated cells. One can infer the identity of a macrophage by its indented nucleus. Macrophages are phagocytic cells that are difficult to find in normal tissues because there is not sufficient cause for them to increase in number. Slide 40 Parathyroid Gland. Adipocytes , fat cells are large cells specialized in storage of neutral fats.
Lipid is removed in routine tissue preparation. Consequently the cell appears as a thin rim of cytoplasm surrounding the vacuole of dissolved lipid. The nucleus is eccentric and flattened. Adipose tissue is a connective tissue with a predominance of adipocytes. Slide 2 Peripheral Nerve, Osmium Tetroxide. Lipid is preserved and stained black when the tissue is prepared using osmium tetroxide as a fixative. Slide 49 Esophagus. Leukocytes are white blood cells that are readily found in connective tissue.
Lymphocytes similar in size to red blood cells are the most common connective tissue leukocyte. Aggregates of lymphocytes are often found associated with the mucosal epithelium of the GI tract, such as this slide of the esophagus.
They have a small amount of slightly basophilic cytoplasm and a large, darkly stained nucleus because of condensed chromatin. Use Slide 51 pyloric stomach to compare lymphocytes no visible cytoplasm to plasma cells which contain abundant cytoplasm.
Cancellous bone looks like a sponge under the microscope and contains empty spaces between trabeculae, or arches of bone proper. It is lighter than compact bone and found in the interior of some bones and at the end of long bones. Compact bone is solid and has greater structural strength. Blood is a fluid connective tissues. Blood has two components: cells and fluid matrix Figure 4. Erythrocytes, red blood cells, transport oxygen and some carbon dioxide. Leukocytes, white blood cells, are responsible for defending against potentially harmful microorganisms or molecules.
Platelets are cell fragments involved in blood clotting. Some white blood cells have the ability to cross the endothelial layer that lines blood vessels and enter adjacent tissues. Nutrients, salts, and wastes are dissolved in the liquid matrix called plasma and transported through the body. Lymph contains a liquid matrix and white blood cells. Lymphatic capillaries are extremely permeable, allowing larger molecules and excess fluid from interstitial spaces to enter the lymphatic vessels.
Lymph drains into blood vessels, delivering molecules to the blood that could not otherwise directly enter the bloodstream. In this way, specialized lymphatic capillaries transport absorbed fats away from the intestine and deliver these molecules to the blood. Visit this link to test your connective tissue knowledge with this question quiz.
Can you name the 10 tissue types shown in the histology slides? Skip to main content. Chapter 4: The Tissue Level of Organization. Search for:. Connective Tissue Learning Objectives Identify and distinguish between the types of connective tissue: loose, dense, cartilage, bone, and blood Explain the functions of connective tissues. Functions of Connective Tissues.
Classification of Connective Tissues. Loose Connective Tissue. Dense Connective Tissue. Elastic connective tissue is a modified dense connective tissue that contains numerous elastic fibers in addition to collagen fibers, which allows the tissue to return to its original length after stretching Figure 4. The lungs and arteries have a layer of elastic connective tissue that allows the stretch and recoil of these organs. Elastic Connective Tissue Elastic connective tissue consists of collagenous fibers with interwoven elastic fibers.
Severe cases of tendinitis can even tear loose a tendon. Surgical repair of a tendon is painful. Connective tissue in the tendon does not have abundant blood supply and heals slowly. While older adults are at risk for tendinitis because the elasticity of tendon tissue decreases with age, active people of all ages can develop tendinitis. Young athletes, dancers, and computer operators; anyone who performs the same movements constantly is at risk for tendinitis.
Although repetitive motions are unavoidable in many activities and may lead to tendinitis, precautions can be taken that can lessen the probability of developing tendinitis. For active individuals, stretches before exercising and cross training or changing exercises are recommended.
For the passionate athlete, it may be time to take some lessons to improve technique. All of the preventive measures aim to increase the strength of the tendon and decrease the stress put on it.
With proper rest and managed care, you will be back on the court to hit that slice-spin serve over the net. Watch this animation to learn more about tendonitis, a painful condition caused by swollen or injured tendons. Two major forms of supportive connective tissue, cartilage and bone, allow the body to maintain its posture and protect internal organs. The distinctive appearance of cartilage is due to polysaccharides called chondroitin sulfates, which bind with ground substance proteins to form proteoglycans.
A layer of dense irregular connective tissue, the perichondrium, encapsulates the cartilage. Cartilaginous tissue is avascular, thus all nutrients need to diffuse through the matrix to reach the chondrocytes. This is a factor contributing to the very slow healing of cartilaginous tissues. The three main types of cartilage tissue are hyaline cartilage, fibrocartilage, and elastic cartilage Figure.
Hyaline cartilage , the most common type of cartilage in the body, consists of short and dispersed collagen fibers and contains large amounts of proteoglycans. Under the microscope, tissue samples appear clear. The surface of hyaline cartilage is smooth. Both strong and flexible, it is found in the rib cage and nose and covers bones where they meet to form moveable joints.
It makes up a template of the embryonic skeleton before bone formation. A plate of hyaline cartilage at the ends of bone allows continued growth until adulthood.
Fibrocartilage is tough because it has thick bundles of collagen fibers dispersed through its matrix. Menisci in the knee joint and the intervertebral discs are examples of fibrocartilage. Elastic cartilage contains elastic fibers as well as collagen and proteoglycans. This tissue gives rigid support as well as elasticity.
Tug gently at your ear lobes, and notice that the lobes return to their initial shape. The external ear contains elastic cartilage. Bone Bone is the hardest connective tissue. It provides protection to internal organs and supports the body. Both components of the matrix, organic and inorganic, contribute to the unusual properties of bone.
Without collagen, bones would be brittle and shatter easily. Without mineral crystals, bones would flex and provide little support. Osteocytes, bone cells like chondrocytes, are located within lacunae.
The histology of transverse tissue from long bone shows a typical arrangement of osteocytes in concentric circles around a central canal. Bone is a highly vascularized tissue. Unlike cartilage, bone tissue can recover from injuries in a relatively short time.
Cancellous bone looks like a sponge under the microscope and contains empty spaces between trabeculae, or arches of bone proper. It is lighter than compact bone and found in the interior of some bones and at the end of long bones. Compact bone is solid and has greater structural strength.
Blood and lymph are fluid connective tissues. Cells circulate in a liquid extracellular matrix. The formed elements circulating in blood are all derived from hematopoietic stem cells located in bone marrow Figure. Erythrocytes, red blood cells, transport oxygen and some carbon dioxide.
Leukocytes, white blood cells, are responsible for defending against potentially harmful microorganisms or molecules. Platelets are cell fragments involved in blood clotting. Some white blood cells have the ability to cross the endothelial layer that lines blood vessels and enter adjacent tissues. Nutrients, salts, and wastes are dissolved in the liquid matrix and transported through the body.
Lymph contains a liquid matrix and white blood cells. Lymphatic capillaries are extremely permeable, allowing larger molecules and excess fluid from interstitial spaces to enter the lymphatic vessels. Lymph drains into blood vessels, delivering molecules to the blood that could not otherwise directly enter the bloodstream. In this way, specialized lymphatic capillaries transport absorbed fats away from the intestine and deliver these molecules to the blood.
View the University of Michigan Webscope to explore the tissue sample in greater detail. Visit this link to test your connective tissue knowledge with this question quiz. Can you name the 10 tissue types shown in the histology slides? Connective tissue is a heterogeneous tissue with many cell shapes and tissue architecture. Structurally, all connective tissues contain cells that are embedded in an extracellular matrix stabilized by proteins.
The chemical nature and physical layout of the extracellular matrix and proteins vary enormously among tissues, reflecting the variety of functions that connective tissue fulfills in the body. Connective tissues separate and cushion organs, protecting them from shifting or traumatic injury. Connect tissues provide support and assist movement, store and transport energy molecules, protect against infections, and contribute to temperature homeostasis.
Macrophages can also present foreign material to T-cells to initiate an immune response. Eosinophils are enriched during parasitic infections and lyse parasites.
Basophils contain secretory granules with similar content to mast cells. Cartilage is a specialized form of connective tissue that is found throughout the body, including joints, ear, nose and trachea. Cartilage is avascular and contains type II collagen fibers that are thinner than type I fibers and are very stable. Cartilage is also rich in glycosaminoglycans. Megacomplexes are prominent in cartilage and consist of the proteoglycan aggregan crosslinked to hyaluronan.
Megacomplexes retain large amounts of water and help cartilage resist compression. Chondrocytes are the cells of cartilage and synthesize all components of cartilage. Questions How would mutations in lysyl oxidase affect collagen? Answer: A mutation that reduced the activity of lysyl oxidase would make collagen fibrils weaker.
Lysyl oxidase generates covalent crosslinks between adjacent collagen trimers. These crosslinks tether trimers to increase the mechanical strength of fibrils.
Answer: Elastic fibers allow tissues to stretch and recoil and are found in structures that are subject to rapid changes in pressure. For example, the aorta must accommodate large changes in blood pressure during systole and diastole. Similarly, the walls of the air spaces in the lung are subjected to to rapid changes in air pressure. Answer: The mutation would most likely be dominant. A cell that contains wild-type and mutant collagen genes would produce a mix of normal and mutated protein.
Both proteins would be randomly incorporated into collagen fibrils so that every fibril would contain some mutated collagen, weakening the fibril and potentially producing some clinical effect. Answer: Collagen fibers would show greater order in tendon.
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