Dense Connective Tissue: tendons, ligaments, aponeuroses, capsules of organs, and dermis. There are two divisions: 1 regular dense connective tissue is characterized by collagen fibers held together in parallel bundles with fibroblasts rows sandwiched in between. If you touch your Achilles tendon, you can feel the strong tension that this tissue must withstand. Tendons attach muscle to bone while ligaments hold two bones together at joints. This tissue serves as the dermis of the skin, the submucosa of the digestive tract, capsules of organs, and tough sheets of fasciae called aponeuroses.
Elastic Connective Tissue : walls of arteries and lungs. This tissue contains wavy, thick elastic fibers which appear as though they can stretch as a rubber band.
The expansion and recoil of these fibers are associated with air entering and leaving the lungs, with the propulsion of blood through large blood vessels, and with voice production in the vocal cords. When you observe the aorta, locate the parallel wavy branching elastic fibers, a few fibroblasts may be present. In this preparation, there is smooth muscle cells present but not stained.
Reticular Connective Tissue : forms stroma of liver, spleen, bone marrow, and lymph nodes. This tissue must be specifically stained and is usually taken from a lymph node or the spleen.
These soft organs need an internal scaffolding called the stroma to hold them together. Reticular fibers provide most of the support for the liver and bone marrow as well. The reticular fibers can be described as delicate, heavily-branched, and dark, the matrix is similar to jello. Adipose Tissue : surrounds heart and kidneys, subcutaneous tissue, and greater omentum.
This is the most easily recognized tissue and will be found widely distributed in every organ microscopically studied this year. The cells are filled with the lipid, triglycerides , and the cytoplasm and nucleus are pushed to the periphery of the cell. Triglycerides are your stored energy, and adipose cells act as good insulators and pillows. There is little matrix associated with adipose tissue but wispy collagenous fibers are threaded between the cells.
Fibroblasts present in these fibers can become adipocytes. Draw and label Adipose Tissue from the Trachea slide :. Hyaline Cartilage : costal cartilages, articular cartilage, ends of nose, trachea walls, and fetal skeleton.
This is a tough, glossy, flexible tissue with many functions; it acts as the model for embryonic bone formation and then remains during bone growth as the epiphyseal plate; it is the articular cartilage covering the ends of bones to prevent friction; and it forms the costal cartilages between the first ten ribs and the sternum.
Components of Blood : From left to right, a diagram of an erythrocyte, thrombocyte, and leukocyte. Leukocytes are usually larger in size 10—14 micrometers in diameter than red blood cells. They lack hemoglobin but contain organelles, a nucleus, and nuclear DNA. They destroy and remove old or aberrant cells and cellular debris, as well as attack infectious agents pathogens and foreign substances.
There are several different types of white blood cells: basophils, eosinophils, neutrophils, monocytes, natural killer cells, B- and T-cell lymphocytes, macrophages, and dendritic cells, all of which perform distinct functions. Thrombocytes measure between one to two micrometers in diameter. These membrane-bound cell fragments lack nuclei and are responsible for blood clotting coagulation. They result from fragmentation of large cells called megakaryocytes, which are derived from stem cells in the bone marrow.
Platelets are produced at a rate of billion per day, a process regulated by the hormone thrombopoietin. The sticky surface of platelets allows them to accumulate at the site of broken blood vessels to form a clot, due in part to the release of clotting factors that occurs during endothelial injury to blood vessels.
This process is called hemostatis. Platelets secrete factors that increase local platelet aggregation e. Platelets are critically important for wound healing, which can only occur once the clot forms and bleeding ceases completely. Blood contains plasma and blood cells, some of which have hemoglobin that makes blood red. The average blood volume in adult is five liters.
Blood is a specialized bodily fluid in animals that delivers necessary substances, such as nutrients and oxygen, to the cells and transports metabolic waste products away from those same cells. Blood plays many roles in sustaining life and has physical characteristics that distinguish it from other body tissues. Blood is a fluid that is technically considered a connective tissue. It is an extracellular matrix in which blood cells are suspended in plasma.
It normally has a pH of about 7. Blood contains red blood cells RBCs , white blood cells WBCs , platelets, and other cell fragments, molecules, and debris. Albumin is the main protein found in plasma, and it functions to regulate the colloidal osmotic pressure of blood. Blood appears red because of the high amount of hemoglobin, a molecule found on RBCs. Each hemoglobin molecule has four heme groups that interact with various molecules, which alters the exact color.
In oxygenated blood found in arterial circulation, hemoglobin-bound oxygen creates a distinctive red color. Deoxygenated blood is a darker shade of red. It is present in veins and can be seen during blood donation or lab tests.
Carbon monoxide poisoning causes bright red blood due to the formation of carboxyhemoglobin. In cyanide poisoning, venous blood remains oxygenated, increasing the redness. Under normal conditions, blood can never truly be blue, although most visible veins appear blue because only blue light can can penetrate deeply enough to illuminate veins beneath the skin. The average adult has a blood volume of roughly five liters 1. Left tube: After standing, the RBCs have settled at the bottom of the tube.
Right tube: contains freshly drawn blood. Blood volume is a regulated variable that is directly proportional to blood pressure through the output of the heart. Most tissues can survive without perfusion for a short amount of time, but the brain needs a continuous supply of oxygen and glucose to stay alive.
Many mechanisms exist to regulate blood volume and tissue perfusion, including renal water excretion in the kidney, the pumping activity of the heart, and the abilities of the arteries to constrict or dilate.
When blood volume becomes too low, such as from an injury, dehydration, or internal bleeding, the body will enter into a state of hypovolemic shock, in which tissue perfusion decreases too much.
Conversely, higher than normal blood volume may cause hypertension, heart failure, and aneurysms. Silver solution should be made fresh with distilled water and clean glassware acid clean is not necessary. Take care to make the silver.
Using old, ammonia depleted ammonium hydroxide can cause the solution to fail. Excess ammonium hydroxide will cause weak staining. Movat Pentachrome is a super connective tissue stain. It is used to study heart tissue, blood vessels and vascular and lung diseases. Due to the excellent differentiation of collagen, elastic, fibrin and muscle fibers, the Movat can reveal subtle changes that the routine and normal special stains do not.
Incubation times and reagent sequence may vary per manufacturer, but results are similar. Alcian blue should be used at PH 2. Complete removal of alkaline alcohol is essential for good staining. Be careful not to over differentiate elastic fibers in ferric chloride.
Dip once or twice then rinse in distilled water and check microscopically. Repeat as necessary. Do not use graded alcohols to dehydrate but start in absolute alcohol. Do not allow sections to dry out during the staining procedure. Rolls, Geoffrey. Sheehan, D. Culling, C.
Cellular Pathology Technique, edition 4. Butterworths, London, England Russel, H. A Modification of the Movat Pentachrome Stain. Arch Pathol, , The content, including webinars, training presentations and related materials is intended to provide general information regarding particular subjects of interest to health care professionals and is not intended to be, and should not be construed as, medical, regulatory or legal advice.
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All rights reserved. For 40 years she shared her passion for histology in research at Yerkes Primate Research Center , in the clinical world managing the Pathology Department at Florida Hospital in Orlando and serving on the board of the Florida State Licensure task Force and as president of the Florida State Society for Histotechnology and in the industry as a Sales executive, Marketing Manager and North American staining sales specialist.
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Unsubscribe at any time. Compact bone is organized into subunits called osteons , as illustrated in Figure 4. A blood vessel and a nerve are found in the center of the structure within the Haversian canal, with radiating circles of lacunae around it known as lamellae.
The wavy lines seen between the lacunae are microchannels called canaliculi ; they connect the lacunae to aid diffusion between the cells.
Spongy bone is made of tiny plates called trabeculae these plates serve as struts to give the spongy bone strength. Over time, these plates can break causing the bone to become less resilient. Bone tissue forms the internal skeleton of vertebrate animals, providing structure to the animal and points of attachment for tendons. Figure 4. Spongy bone, inside the compact bone, is porous with web-like trabeculae.
Blood vessels, nerves, and lymphatic vessels are found in the central Haversian canal. Rings of lamellae surround the Haversian canal. Between the lamellae are cavities called lacunae.
Canaliculi are microchannels connecting the lacunae together. Osteoclasts bore tunnels into the bone and osteocytes are found in the lacunae. Figure 5. Adipose is a connective tissue is made up of cells called adipocytes. Adipocytes have small nuclei localized at the cell edge. Adipose tissue, or fat tissue, is considered a connective tissue even though it does not have fibroblasts or a real matrix and only has a few fibers.
Adipose tissue is made up of cells called adipocytes that collect and store fat in the form of triglycerides, for energy metabolism. Adipose tissues additionally serve as insulation to help maintain body temperatures, allowing animals to be endothermic, and they function as cushioning against damage to body organs. Under a microscope, adipose tissue cells appear empty due to the extraction of fat during the processing of the material for viewing, as seen in Figure 5.
The thin lines in the image are the cell membranes, and the nuclei are the small, black dots at the edges of the cells. Blood is considered a connective tissue because it has a matrix, as shown in Figure 6.
The living cell types are red blood cells RBC , also called erythrocytes, and white blood cells WBC , also called leukocytes. The fluid portion of whole blood, its matrix, is commonly called plasma. Figure 6. Blood is a connective tissue that has a fluid matrix, called plasma, and no fibers.
Erythrocytes red blood cells , the predominant cell type, are involved in the transport of oxygen and carbon dioxide. Also present are various leukocytes white blood cells involved in immune response. The cell found in greatest abundance in blood is the erythrocyte. Erythrocytes are counted in millions in a blood sample: the average number of red blood cells in primates is 4.
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