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75 Cards in this Set
- Front
- Back
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What are the components of connective tissue? |
Connective tissue includes: ground substance, fibers, and cells.
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Which classes of compounds are found in ground substance?
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Glycosaminoglycans (GAGs) and structural glycoproteins
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What is the function of the ground substance?
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Its main function is to act as a medium for nutrient transport and waste removal from cells.
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What are the five primary GAGs?
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Hyaluronic acid, chondroitin sulfate, dermatan sufate, keratan sulfate, and heparin sulfate. Remember that these molecules all have a repetitive disaccharide motif.
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Which of the primary GAGs do not have a protein core?
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Hyaluronic acid does not have a protein core.
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Which type of fibers are present in connective tissue?
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Collagen, reticular fibers, and elastic fibers.
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What is the most abundant fiber in the body?
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Collagen; It makes up 30% of the body's dry weight.
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What is the structural unit of collagen?
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Tropocollagen
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What is the most common type of collagen?
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Collagen type I; It is found in the dermis, bone, tendons, dentin, fascia, sclera, and fibrous cartilage.
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What type of collagen is found in Hyaline and elastic cartilage?
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Collagen type II
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What type of collagen is found in reticular fibers?
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Collagen type III
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Which type of collagen is found in the basal lamina
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Collagen type IV
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Which type of fibers can be produced by smooth muscle cells or fibroblasts?
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Elastic fibers; remember that elastic fibers are commonly found in blood vessels.
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What do fibroblasts produce?
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Fibroblasts synthesize and secrete all connective tissue fibers (collagen, reticular fibers, and elastic fibers) and the ground substance (GAGs and structural glycoproteins).
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Monocytes are the precursor cell to what other cell?
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Macrophages
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What is the function of a macrophage?
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They ingest (phagocytose) foreign matter and stimulate the immune system via antigen processing.
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Which cell is the progenitor of plasma cells?
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The B Lymphocyte, which matures in the bone marrow.
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Which cell type produces antibodies?
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Plasma cells
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Mast cell granules contain what compounds?
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Mast granules include GAGs, hisamine, proteases, and heparin.
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What is the Neutrophil's role in immunity?
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Neutrophils are attracted to the site of infection via chemotaxis, once they arrive they phagocytose foreign material and release granules responsible for the characteristic signs of inflammation including: dolor, calor, tumor, and rubor
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Which cells synthesize and store lipids?
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Adipocytes
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Describe the difference between yellow and brown fat?
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Yellow fat is the predominant form and is composed of a single large lipid droplet. Brown fat is mostly found in infants and hibernating animals. Brown fat contains multiple small droplets with numerous mitochondria; it is believed to be involved in thermoregulation.
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Which organelles are present in a mature erythrocyte?
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Mature erythrocytes do not contain organelles, instead they are filled with hemoglobin (a protein which reversibly binds oxygen).
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List the leukocytes in ascending abundance.
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From least to greatest: basophils (0.5%), monocytes (1-5%), eosinophils (~5%), lymphocytes (20-50%), and neutrophils (40-75%)
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Which cell is the progenitor of platelets and where are they found?
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Megakaryocytes are giant cells which produce platelets; they are found in the bone marrow.
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Name and describe the first phase of hematopoiesis.
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Mesoblastic phase; the production of nucleated red blood cells by mesenchymal cells in the yolk sac beginning the third week of gestation.
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During what hematopoietic phase are red blood cells formed in the liver, thymus, and spleen?
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During the Hepatic phase (between weeks 4 and 8 of gestation).
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Describe the myeloid phase of hematopoiesis. |
Following the 12th week of gestation hematopoiesis occurs in bone marrow, initially developing pluripotent stem cells which give rise to lymphoid multipotent cells (which mature as T or B lymphocytes), or myeloid multipotent cells (which mature as erythrocytes or non-lymphocyte leukocytes).
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What is the distribution of loose (areolar) CT?
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Surrounds muscles and supports epithelial tissues of all organs.
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What is the distribution of dense irregular CT?
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Dense irregular CT is found in the dermis of skin.
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Where is dense regular CT found?
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Dense regular CT is found in tendons.
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Where is elastic CT found? Which cells produce the elastic fibers?
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Elastic fibers are found in the walls of large arteries; elastic fibers are produced by smooth muscle cells and fibroblasts.
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What is the collagen type found in Reticular CT? Where is reticular CT found?
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Collagen type III; They form the framework of the hematopoietic region within bone marrow and are found in lymph nodules/nodes and the spleen.
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What is cartilage ground substance made of?
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Primarily chondroitin sulfate.
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What are the two growth methods for cartilage? Briefly describe each.
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Appositional and interstitial; appositional growth of cartilage is driven by chondroblasts laying down cartilage matrix and interstitial growth is growth through division of chondrocytes to form isogenous groups.
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Hyaline cartilage features which type of collagen?
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Type II collagen.
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Where is hyaline cartilage distributed?
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It's found in the nose, larynx, trachea, bronchi, and at bone surfaces of joints. Hyaline cartilage also makes up the fetal skeleton.
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Which type of cartilage frequently features lipid droplets?
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Lipid droplets are frequently found within chondrocytes of elastic cartilage.
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Where is elastic cartilage distributed?
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Elastic cartilage is found in the external ear, the epiglottis, and part of the larynx.
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Which type of cartilage was described as "blending insensibly" with other types of cartilage, fibrous tissue, or bone?
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Fibrocartilage
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What are the two components of the perichondrium?
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The fibrous and chondrogenic layers.
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What type of collagen is present in fibrous cartilage?
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Type I collagen
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Which type of collagen is the strongest?
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Fibrocartilage
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The calcification of cartilage in response to alkaline phosphatase is termed what? Under what circumstances does it occur?
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It is termed a regressive change; Calcification of cartilage occurs as an early phase of bone formation and increasingly occurs outside of ossification as we age.
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Describe the vascularity of cartilage.
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Cartilage is avascular so its nutrients are supplied and its waste ridded via diffusion.
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What is the influence of calcium on the diffusion of nutrients in cartilage?
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After the cartilagenous matrix is calcified there is no longer adequate diffusion for cell life.
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What is the distribution of fibrous cartilage?
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Fibrous cartilage is found in the annulus fibrosus, pubis symphysis, and at the tendon/bone interface.
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What are the two mechanisms of bone formation?
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Intermembranous (where mesenchymal cells develop into bone) and endochondral (where cartilage is replaced by bone).
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Which type of bone is characterized as highly cellular with irregular matrix deposition and relatively low mineral content?
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Woven (Immature) bone
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What are the two types of lamellar (mature) bone?
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Lamellar bone is organized into two subsets based on texture: compact lamellar and spongy lamellar.
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Describe the vascularity of bone.
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Bones are highly vascular, so they attain nutrients and void waste via blood vessels.
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What is the only means of bone growth?
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Appositional bone growth.
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Where is the site of hematopoiesis?
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In the red marrow which is situated in the diaphysis of long bones.
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What is the difference between periosteum and endosteum?
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The periosteum is the surface which immediately surrounds the outer surface of bones; it is composed of dense CT (outermost portion) and an osteogenic layer which features osteoblasts (inner portion). The endosteum lines all internal surfaces of bone (the marrow cavity) and is composed of a single layer of osteoblasts.
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Describe the architecture of flat bones, such as the skull bones.
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They comprise an inner and outer table of thick compact lamellar bone with a spongy bone diploe in between.
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What are the specialized names of outer and inner periosteum of the flat bones of the skull?
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The outer and inner periosteum are called pericranium and dura mater respectively.
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Describe the process of appositional bone deposition.
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Osteoblasts secrete osteoid (a substance containing type I collagen fibers and chondroitin sulfate) followed by alkaline phosphatase which calcifies the osteoid matrix.
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What are osteoblasts called once they are completely surrounded by bony matrix?
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Osteocytes
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What is the progenitor cell to the osteoclast?
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The monocyte
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Which proteolytic enzyme is responsible for bone resorption?
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Acid phosphatase (an enzyme secreted by osteoclasts).
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Describe the function of the organic and inorganic portions of bone.
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The organic portion (collagen fibers/chondroitin sulfate) confers toughness and resiliency. The inorganic portion (Calcium, Phosphate, ect.) provide the hardness. Remember Dr. Haar's demonstration with the bone soaked in acetic acid.
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What is the primary structural unit of compact bone?
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The structural unit of compact bone is the haversian system; haversion systems feature a central haversian canal, concentric lamellae, and canaliculi which interconnect lacuane.
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What is the stimulus for intramembranous ossification?
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Increased oxygen provided by increased vascularization causes mesenchymal cells to multiply and differentiate into osteoblasts.
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All surfaces within spongy bone are lined with what?
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Endosteum
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Which bones develop completely via intramembranous bone development?
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The flat bones of the skull (frontal, parietal, occipital, temporal, and a portion of the mandible). Intramembranous bone formation contributes to the development of most other bones.
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Describe woven bone.
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Woven bone is the immature bone which is the original product of the bony matrix secreted by osteoblasts.
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What is the fate of woven bone?
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Woven bone trabeculae are lined by endosteum (osteoblasts) which continue to secrete bony matrix until it surrounds the blood vessels--forming primative haversion systems.
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Is the periosteal band formed intramembranously or endochondrally?
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The periosteal band is developed by the conversion of a perichondrium into a periosteum by chondroblasts converting into osteoblasts.
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What is bone formed by replacement of cartilage called?
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Endochondral bone development.
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Which bones are developed via endochondrally?
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Endochondral bone development occurs in basilar skull bones, bones of extremities, and those of the vertebral column, the pelvis, and the ribs.
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Recall the steps of endochondral ossification.
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A hyaline cartilage model of the bone is produced in the fetus (from mesenchyme), chondrocytes at the center of the cartilagenous model undergo regressive change, ultimately leading to calcification of the cartilage matrix (induced by alkaline phosphatase) and subsequent death of the chondrocytes. With calcified matrix remaining internally, vascularization begins in the perichondrium which converts it to a periosteum (intramembranous bone formation). The periosteal bud which supplys the vessels to the matrix carries osteogenic cells into the matrix which begin to lay down bone.
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How do bones grow in length?
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Via interstitial growth of chondrocytes within the epiphyseal plate.
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What are interstitial lamellae?
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Intestitial lamellae are the remains of old haversian systems, which were typically partially resporbed.
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Describe articular cartilage and its function.
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Articular cartilage is present on the surface of the epiphysis and it helps absorb mechanical pressure experienced at joints.
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What is synovial fluid?
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Synovial fluid is a filtrate of blood which has a notable high concentration of hyaluronic acid. |
