Chapter 4- Histology: The Study of Tissues (no photos) – Flashcards
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Epithelial Tissue
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Consists almost entirely of cells. Covers body surfaces and forms glands
Outside surface of the body. Lining of digestive, respiratory and urogenital systems
Heart and blood vessels. Linings of many body cavities
Has free, basal, and lateral surfaces. Basement membrane. Specialized cell contacts
Avascular. Regenerate
Outside surface of the body. Lining of digestive, respiratory and urogenital systems
Heart and blood vessels. Linings of many body cavities
Has free, basal, and lateral surfaces. Basement membrane. Specialized cell contacts
Avascular. Regenerate
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Basement Membrane
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Extracellular: formed by secretions of both epithelium and connective tissue. Acellular "glue"
Attachment to C.T. Guides cell migration during tissue repair
Acts as a filter in the nephron of the kidney
Attachment to C.T. Guides cell migration during tissue repair
Acts as a filter in the nephron of the kidney
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Functions of Epithelial Tissue
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Protecting underlying structures. Acting as barriers.
Permitting the passage of substances.Secreting substances .Absorbing substances
Permitting the passage of substances.Secreting substances .Absorbing substances
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Functions of Epithelial Tissue
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Protecting underlying structures. Acting as barriers.
Permitting the passage of substances.Secreting substances .Absorbing substances
Permitting the passage of substances.Secreting substances .Absorbing substances
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Cell Connections
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Found on lateral and basal surfaces of cells
Functions: Form permeability layer. Bind cells together
Provide mechanism for intercellular communication
Functions: Form permeability layer. Bind cells together
Provide mechanism for intercellular communication
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Desmosomes
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disk-shaped regions of cell membrane; often found in areas that are subjected to stress.Contain especially adhesive glycoproteins.
Intermediate protein filaments extend into cytoplasm of cells.
Striated squamous epithelium of the skin.
Intermediate protein filaments extend into cytoplasm of cells.
Striated squamous epithelium of the skin.
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Hemidesmosomes
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half of a desmosome; attach epithelial cells to basement membrane.
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Tight Junctions
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hold cells together, form permeability barrier
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zonula adherens
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between adjacent cells, weak glue, hold cells together. Simple epithelium.
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zonula occludens
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permeability barrier, (stomach and urinary bladder)
chemicals cannot pass between cells.
chemicals cannot pass between cells.
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Gap Junctions
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protein channels aid intercellular communication.
Allows ions and small molecules to pass through.
Coordinate function of cardiac and smooth muscle.
May help coordinate movement of cilia in ciliated types of epithelium
Allows ions and small molecules to pass through.
Coordinate function of cardiac and smooth muscle.
May help coordinate movement of cilia in ciliated types of epithelium
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Endocrine
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no open contact with exterior; no ducts; produce hormones
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Exocrine
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open contact maintained with exterior; ducts
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Glands
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Epithelium with supporting network of C.T.
Two types of glands formed by infolding of epithelium. Exocrine glands classified either by structure or by the method of secretion
Classified by structure
Unicellular: goblet cells
Multicellular
Two types of glands formed by infolding of epithelium. Exocrine glands classified either by structure or by the method of secretion
Classified by structure
Unicellular: goblet cells
Multicellular
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Multicellular Exocrine Glands
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Classified on the basis of types of ducts or mode of secretion
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Simple
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ducts with few branches
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Compound
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ducts with many branches
If ducts end in tubules or sac-like structures: acini-> Pancreas
If ducts end in simple sacs: alveoli->Lungs
If ducts end in tubules or sac-like structures: acini-> Pancreas
If ducts end in simple sacs: alveoli->Lungs
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Connective Tissue
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Abundant; found in every organ
Consists of cells separated by extracellular matrix
Many diverse types
Performs variety of important functions
Consists of cells separated by extracellular matrix
Many diverse types
Performs variety of important functions
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Functions of Connective Tissue
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Enclose organs as a capsule and separate organs into layers
Connect tissues to one another. Tendons and ligaments.
Support and movement. Bones.
Storage. Fat.
Cushion and insulate. Fat.
Transport. Blood.
Protect. Cells of the immune system.
Connect tissues to one another. Tendons and ligaments.
Support and movement. Bones.
Storage. Fat.
Cushion and insulate. Fat.
Transport. Blood.
Protect. Cells of the immune system.
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Cells of Connective Tissue
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Specialized cells produce the extracellular matrix
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Blasts
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create the matrix, example osteoblast (cell that makes bone)
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Cytes
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maintain the matrix, example chondrocyte (a cell that has secreted the matrix of cartilage and become embedded in it)
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Clasts
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break the matrix down for remodeling, example osteoclasts (a large multinucleate bone cell that absorbs bone tissue during growth and healing)
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Adipose or fat cells (adipocytes
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Common in some tissues (dermis of skin); rare in some (cartilage)
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Mast cells
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Common beneath membranes; along small blood vessels. Can release heparin, histamine, and proteolytic enzymes in response to injury
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White blood cells (leukocytes).
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Respond to injury or infection
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Macrophages
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Phagocytize or provide protectionFixed: stay in position in connective tissue
Wandering: move by amoeboid movement through the connective tissue
Wandering: move by amoeboid movement through the connective tissue
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Platelets
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Fragments of hematopoietic cells involved in clotting.
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Undifferentiated mesenchyme (stem cells)
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Have potential to differentiate into adult cell types.
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Collagen (Protein fibers of the matrix)
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Most common protein in body; strong, flexible, inelastic
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Reticular (Protein fibers of the matrix)
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Fill spaces between tissues and organs. Fine collagenous, form branching networks
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Elastic (Protein fibers of the matrix)
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Returns to its original shape after distension or compression. Contains molecules of protein elastin that resemble coiled springs; molecules are cross-linked
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Hyaluronic acid
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polysaccharide. Good lubricant. Vitreous humor of eye.
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Proteoglycans
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protein and polysaccharide. Protein part attaches to hyaluronic acid. Trap large amounts of water.
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Adhesive molecules
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hold proteoglycan aggregates together. Chondronectin in cartilage, osteonectin in bone, fibronectin in fibrous connective tissue
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Connective Tissue Proper
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Loose (areolar). Collagenous fibers are loosely arranged
Dense. Fibers form thick bundles that nearly fill all extracellular space. Supporting CT-Cartilage Bone Fluid CT-Blood
Dense. Fibers form thick bundles that nearly fill all extracellular space. Supporting CT-Cartilage Bone Fluid CT-Blood
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Loose (Areolar) Connective Tissue
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Loose packing material of most organs and tissues, also known as stroma
Attaches skin to underlying tissues. Superficial fascia = subcutaneous layer = hypodermis
Contains collagen, reticular, elastic fibers and all five types of cells
Often seen in association with other types of C.T., like reticular tissue and fat
Cells include fibroblasts, mast cells, lymphocytes, adipose cells, macrophages
Attaches skin to underlying tissues. Superficial fascia = subcutaneous layer = hypodermis
Contains collagen, reticular, elastic fibers and all five types of cells
Often seen in association with other types of C.T., like reticular tissue and fat
Cells include fibroblasts, mast cells, lymphocytes, adipose cells, macrophages
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Connective Tissue with Special Properties-Adipose
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Predominant cells are adipocytes
Yellow (white). Most abundant type, has a wide distribution. White at birth and yellows with age.
Carotenes come from plants and can be metabolized into vitamin A.
Scant ring of cytoplasm surrounding single large lipid droplet. Nuclei flattened and eccentric.
Brown. Found only in specific areas of body: axillae, neck and near kidneys
Cells are polygonal in shape, have a considerable volume of cytoplasm and contain multiple lipid droplets of varying size. Nuclei are round and almost centrally located.
Yellow (white). Most abundant type, has a wide distribution. White at birth and yellows with age.
Carotenes come from plants and can be metabolized into vitamin A.
Scant ring of cytoplasm surrounding single large lipid droplet. Nuclei flattened and eccentric.
Brown. Found only in specific areas of body: axillae, neck and near kidneys
Cells are polygonal in shape, have a considerable volume of cytoplasm and contain multiple lipid droplets of varying size. Nuclei are round and almost centrally located.
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Reticular Tissue
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Forms superstructure of lymphatic and hemopoietic tissues
Network of fine reticular fibers and reticular cells.
Spaces between cells contain white cells and dendritic
Network of fine reticular fibers and reticular cells.
Spaces between cells contain white cells and dendritic
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Tendons
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Connect muscles to bones;fibers are not necessarily parallel
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Ligaments
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Connect bones to bones. Collagen often less compact, usually flattened, form sheets or bands
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nuchal ligament
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Ligaments in vocal folds
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Dense Irregular Collagenous Connective Tissue
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Protein fibers arranged in a randomly oriented network
Forms innermost layer of the dermis of the skin, scars, capsules of kidney and spleen
Forms innermost layer of the dermis of the skin, scars, capsules of kidney and spleen
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Dense Irregular Elastic Connective Tissue
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Bundles and sheets of collagenous and elastic fibers oriented in multiple directions
In walls of elastic arteries
Strong, yet elastic
In walls of elastic arteries
Strong, yet elastic
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Supporting Connective Tissue: Cartilage
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Composed of chondrocytes located in matrix-surrounded spaces called lacunae. Firm consistency.
Ground substance: Proteoglycans and hyaluronic acid complexed together trap large amounts of water. Tissue can spring back after being compressed.
Avascular and no nerve supply. Heals slowly
Ground substance: Proteoglycans and hyaluronic acid complexed together trap large amounts of water. Tissue can spring back after being compressed.
Avascular and no nerve supply. Heals slowly
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Perichondrium
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Dense irregular connective tissue that surrounds cartilage. Fibroblasts of perichondrium can differentiate into chondroblasts.
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Hyaline Cartilage
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Structure: large amount of collagen fibers evenly distributed in proteoglycan matrix. Smooth surface in articulations
Locations:
Found in areas for strong support and some flexibility: rib cage, trachea, and bronchi
In embryo forms most of skeleton
Involved in growth that increases bone length
Locations:
Found in areas for strong support and some flexibility: rib cage, trachea, and bronchi
In embryo forms most of skeleton
Involved in growth that increases bone length
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Fibrocartilage
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Structure: thick collagen fibers distributed in proteoglycan matrix; slightly compressible and very tough
Locations: found in areas of body where a great deal of pressure is applied to joints
Knee, jaw, between vertebrae
Locations: found in areas of body where a great deal of pressure is applied to joints
Knee, jaw, between vertebrae
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Elastic Cartilage
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Structure: elastic and collagen fibers embedded in proteoglycans. Rigid but elastic properties
Locations: external ears and epiglottis
Locations: external ears and epiglottis
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Supporting Connective Tissue: Bone
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Hard connective tissue composed of living cells (osteocytes) and mineralized matrix
Matrix: gives strength and rigidity; allows bone to support and protect other tissues and organs
Organic: collagen fibers
Inorganic: hydroxyapatite (Ca plus PO4)
Matrix: gives strength and rigidity; allows bone to support and protect other tissues and organs
Organic: collagen fibers
Inorganic: hydroxyapatite (Ca plus PO4)
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Spongy bone
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trabeculae of bone with spaces between. Looks like a sponge. Found inside bones.
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Compact bone
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arranged in concentric circle layers around a central canal that contains a blood vessel. Found on periphery of bones.
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Fluid Connective Tissue: Blood
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Matrix: plasma
Liquid and lacks fibers.
Matrix formed by other tissues, unlike other types of connective tissue.
Moves through vessels, but both fluid and cells can move in/out of the vessels.
Formed elements: red cells, white cells, and platelets
Hemopoietic tissue
Forms blood cells
Two types of bone marrow
Yellow
Red
Liquid and lacks fibers.
Matrix formed by other tissues, unlike other types of connective tissue.
Moves through vessels, but both fluid and cells can move in/out of the vessels.
Formed elements: red cells, white cells, and platelets
Hemopoietic tissue
Forms blood cells
Two types of bone marrow
Yellow
Red
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Fluid Connective Tissue: Hemopoietic Tissue
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Forms blood cells
Found in bone marrow
Types of bone marrow
Red: hemopoietic tissue surrounded by a framework of reticular fibers. Produces red and white cells
Yellow: yellow adipose tissue
As children grow, yellow marrow replaces much of red marrow
Found in bone marrow
Types of bone marrow
Red: hemopoietic tissue surrounded by a framework of reticular fibers. Produces red and white cells
Yellow: yellow adipose tissue
As children grow, yellow marrow replaces much of red marrow
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Skeletal
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most attached to skeleton, but some attached to other types of connective tissue. Striated and voluntary.
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Cardiac
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muscle of the heart. Striated and involuntary. Pumps the blood
is under involuntary (unconscious) control
is under involuntary (unconscious) control
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Smooth
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muscle associated with tubular structures and with the skin. Nonstriated and involuntary.
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Neurons or nerve cells
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the ability to produce action potentials
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Cell body
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contains nucleus
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Axon
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cell process; conducts impulses away from cell body; usually only one per neuron
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Dendrite
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cell process; receive impulses from other neurons; can be many per neuron
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Nervous Tissue: Neuroglia
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Support cells of the brain, spinal cord and nerves
Nourish, protect, and insulate neurons
Nourish, protect, and insulate neurons
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Mucous- Tissue Membrane
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Line cavities that open to the outside of body
Secrete mucus
Contains epithelium with goblet cells, basement membrane, lamina propria (sometimes with smooth muscle)
Found in respiratory, digestive, urinary and reproductive systems.
Secrete mucus
Contains epithelium with goblet cells, basement membrane, lamina propria (sometimes with smooth muscle)
Found in respiratory, digestive, urinary and reproductive systems.
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Serous- Tissue Membrane
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simple squamous epithelium called mesothelium, basement membrane, thin layer of loose C.T.
Line cavities not open to exterior
Pericardial, pleural, peritoneal
Line cavities not open to exterior
Pericardial, pleural, peritoneal
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Tissue Repair
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Substitution of dead/damaged cells by viable/functional cells
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Labile
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capable of mitosis through life. skin, mucous membranes, hemopoietic tissue, lymphatic tissue
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Stable
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no mitosis after growth ends, but can divide after injury. Liver, pancreas, endocrine cells
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Permanent
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if killed, replaced by a different type of cell. Limited regenerative ability. nervous, skeletal and cardiac muscle
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Primary union- Skin Repair
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Edges of wound are close together
Wound fills with blood
Clot forms: fibrin threads start to contract; pull edges together
Scab
Inflammatory response; pus forms as white cells die
Granulation tissue. Replaces clot, delicate C.T. composed of fibroblasts, collagen fibers, capillaries
Scar. Formed from granulation tissue. Tissue turns from red to white as capillaries are forced out.
Wound fills with blood
Clot forms: fibrin threads start to contract; pull edges together
Scab
Inflammatory response; pus forms as white cells die
Granulation tissue. Replaces clot, delicate C.T. composed of fibroblasts, collagen fibers, capillaries
Scar. Formed from granulation tissue. Tissue turns from red to white as capillaries are forced out.
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Secondary union- Skin Repair
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Edges of wound are not closed; greater chance of infection
Clot may not close gap
Inflammatory response greater
Wound contraction occurs leading to greater scarring
Clot may not close gap
Inflammatory response greater
Wound contraction occurs leading to greater scarring
