Histo I: Connective, muscle and neural tissues Flashcards
name the 2 types of connective tissue proper
fibrous connective tissue and special (connective with special features)
name the 2 types of fibrous connective tissue
loose connective and dense connective
name the 2 types of dense connective tissue
dense regular connective tissue and dense irregular connective tissue
name 4 types of special connective tissues
mesenchymal-, gelatinous- (mucous), reticular-, and adipose connective tissue
categories of adipose tissue
white and brown
name connective tissue fibers (3)
Collagen fibers, Elastic fibers, Reticular fibers
name connective tissue ground substances (3)
Proteoglycans, Glycoproteins, Glycosaminoglycans
name as many types of connective tissue cells as you can
Fibroblasts and fibrocytes, Blood cells, Plasma cells, Macrophages (histiocytes), Mast cells, Pigment cells (melanocytes), Fat cells (lipocytes, adipocytes), Pericytes
What are fibroblasts?
Fibroblasts are the most common type of connective tissue cell.
Are immature flattened cells responsible for the formation of fibers (collagen, elastic and reticular) and the amorphous material.
Describe the morphology of fibroblasts.
They are irregularly shaped and have several short, thick processes.
What are fibrocytes?
Fibrocytes are mature, slender, spindle-shaped or flattened connective tissue cells that produce connective tissue proteins such as collagen.
Describe the morphology of fibrocytes.
Have long, thin processes and poorly developed organelles.
What are macrophages?
Or histiocytes - are a type of phagocytic dense, fibrous connective tissue formed from monocytes.
Describe the morphology of histiocytes.
Relatively large cells with irregular outline. Nucleus is spherical or ellipsoidal; cytoplasm contain well-developed Golgi complex and a variable number of lysosomes.
What do the granules of mast cells contain?
The granules of mast cells contain heparin (inhibits blood coagulation) and histamine (involved in local inflammatory reactions and edema by increasing capillary permeability).
Describe the morphology of mast cells.
Rounded or elongated form. The nucleus is relatively small, cytoplasm contain large number of granules which stain with basic dyes
What are mast cells?
A type of white blood cell that are found in connective tissues.
Contribute to homeostasis in the immune system, serve as a first line of defense against antigens.
What are plasma cells?
A plasma cell is a type of white blood cell/immune cell. Develop from activated B cells.
Describe the morphology of plasma cells.
Ovoid cells, abundant cytoplasm, nucleus is spherical and eccentric. Cytoplasm is basophilic because highly developed granular endoplasmic reticulum (ergastoplasm).
What is the function of plasma cells?
Their function is to produce antibodies and, thus, they are actively involved in the defense of the organism.
What are adipocytes?
Fat cells, a type of connective tissue.
Describe the morphology of adipocytes.
Contain droplets of fat. Narrow rim of cytoplasm contains flattened nucleus and organelles.
What are melanocytes?
Pigment cells that contain granules of melanin.
What are pericytes?
Are multipotential connective tissue progenitors which are able to differentiate into a variety of cells; osteoblasts, chondrocytes and fibroblasts.
Describe collagen fibers.
Composed of protein collagen, have great tensile strength, are inelastic, measure between 1-10 µm in thickness and are of indefinite length.
Describe elastic fibers.
Composed of protein elastin, less strong than collagen; stretch easily but return to their original length when stretching force is removed.
Branch and anastomose to form networks.
What are reticular fibers?
Very thin collagen fibers
Purpose of Amorphous material, or ground substance?
The material in which the cells and the fibers are embedded.
Permits diffusion of fluids containing nutrients and waste products between blood and lymph capillaries and cells.
Gel-like nature provides support for the tissue.
Describe loose connective tissue.
Very common; delicate consistency, flexible and well vascularized.
What is the function of loose connective tissue?
Supports epithelia, surrounds blood vessels.
Fills spaces between muscle and nerve fibers.
Where is loose connective tissue found?
Papillary layer of dermis; hypodermis
Describe dense irregular connective tissue.
Dense and irregular,
fewer cells than in loose connective tissue;
predominance of collagen fibers arranged without clear orientation,
less flexible, but more resistant to stress.
Where is dense irregular connective tissue found?
Dermis (lower layers of the skin) and in sclera.
Describe dense regular connective tissue.
Dense regular; collagen bundles are arranged in parallel array. Great resistance to traction forces.
Where is dense regular connective tissue found?
Tendons and ligaments
Describe mesenchyme.
Mesenchyme is embryonic undifferentiated loose connective tissue made up of spindle-shaped cells.
Extracellular matrix is occupied by viscous ground substance; reticular collagen fibers are fine and relatively sparse.
Describe mucous connective tissues.
Abundant gelatin-like ground substance -> “Wharton’s jelly”, thin collagen fibers.
Function of mesenchyme?
During embryogenesis, mesenchyme gives rise to the body’s connective tissues.
Loose nature of cells allows the tissue to move and to be molded.
Function of mucous connective tissues?
Embryonic connective tissue.
Where is mucous connective tissues found?
Umbilical cord
Describe reticular connective tissue.
Reticular fibers form 3D network that supports the reticular tissue (reticular cells + reticular fibers).
Function of reticular connective tissue?
Creates special microenvironment for hemopoietic and lymphoid organs.
Where is reticular connective tissue found?
Bone marrow, spleen, lymph nodes
What is the mononuclear phagocytic system?
A system and family of cells comprising; bone marrow progenitors, osteroclasts, monocytes and tissue macrophages /histiocytes.
Function of mononuclear phagocytic system?
Main function is phagocytosis.
Tissue repair and remodeling, resolution of inflammation, maintenance of homeostasis, and disease progression.
Name 3 types of cartilages.
hyaline cartilage
elastic cartilage
fibrous cartilage (fibrocartilage)
Name 2 types of bone material.
lamellar bone (compact and spongy or cancellous bones) woven bone (fibrous bone)
What is cartilage tissue composed of?
chondrocytes
Where are chondrocytes located in cartilage?
Chondrocytes are dispersed in the extracellular matrix within lacunae.
Describe the extracellular matrix of cartilage.
Extracellular matrix of cartilage consists of fibers, which are embedded in the ground substance.