Tissues

Tissues

1. Muscle

   • Smooth
     • Involuntary muscle that can not be stimulated to contract by conscious effort. They are spindle shaped with a single centrally located nucleus. Composes the walls of hollow internal organs, (stomach, intestines, urinary bladder, uterus, and blood vessels.
   • Skeletal
     • Voluntary muscle that attaches to the bone and can be controlled by conscious effort, has striation. Each cell has many nuclei. Stimulated by nerve cells
   • Cardiac
     • Involuntary muscle- cardiac muscle can continue to function without nervous stimulation. Located only in the heart. Cells are striated and branched, joined end to end, and interconnected in a specialized junction called an intercalated disk. Each cardiac muscle has a single nucleus.
   • a bundle of fibrous tissue in the human body that is able to contract producing movement

2. Nervous

   • Neurons
     • Also known as nerve cells. Sense certain types of changes in their surroundings. Incoming signals stimulate cellular processes called dendrites which may cause neurons to respond by conduction electrical impulses along cellular processes call axons to other neurons or to muscles or glands. They coordinate regulate and integrate many body functions.
   • Neuroglia
     • Plays a major role in cell communications. Supports and binds the components of nervous tissue, carry on phagocytosis and help supply growth factors and nutrients to neurons by connecting them to blood vessels. They divide and are crucial to the function of neurons.
   • located in the brain, spinal cord, and peripheral nerves.

3. Connective

   • Fibers
     • Collageous
       • made of thick thread of collagen and are in tendons and ligaments.
     • Elastic
       • bundles of elastin and are in air passages/vocal chords
     • Reticular
       • made of thin collagenous fibers and form branched networks to provide support
   • Specialized
     • Cartilage
       • Elastic
         • More flexible than hyaline because its extracellular matrix has a dense network of elastic fibers. Found in the outer ear, and part of the larynx. Provides flexible framework.
       • Hyaline
         • Most common type of cartilage. Looks like white glass. found in the ends of bones, nose, and rings in the respiratory passages.
       • Fibroid
         • Many collagen fibers, therefore the toughest type. Can be found between the vertebrae, in the knee, and parts of the pelvic girdle. Absorbs shock during body movement.
       • Rigid connective tissue. Covered in a thin layer of tissue, known as the perichondrium. Matrix consists of collagenous fibers in a gel like ground substance
     • Blood
       • composed of cells in a fluid extracellular matrix called plasma. These cells include red blood cells, white blood cells, and cellular fragments called platelets. Erythrocytes are red blood cells, and leukocytes are white blood cells. Blood transports gases, nutrients, and wastes. It defends against disease and acts in clotting. Found in blood vessels.
     • Bone
       • composed of osteocytes in a hard calcified matrix. Most rigid connective tissue. Stores inorganic cells. Found in the skeleton and middle ear. Gap junctions connect osteocytes together. Provides framework for muscle attachment. Bone contains red marrow which forms blood cells.
   • Proper
     • Elastic Connective
       • made up of elastic fibers found in the extracellular matrix, very rare. Present in high concentration in several organs, including the largest arteries in the body. They can stretch up to 1.5 times their length.
     • Adipose
       • Develops when adipocytes store fat in droplets in their cytoplasm. Tissue lies beneath the skin between muscles and around kidneys, behind eyes, abdominal membranes, surfaces of the heart, and around joints. It serves as protection and cushion and stores energy
     • Loose Connective
       • Areolar, forms delicate thin membranes throughout body holds organs in place and attaches epithelial tissue in the vertebrae, found in subcutaneous tissue under the skin and around organs
     • Dense Connective
       • Consists of regular and irregular. Closely packed, thick collagen fibers, fine elastic fibers and fibroblasts. Collagen fibers are thick and withstand forces. They bind structures as part of tendons and ligaments. Irregular is thicker interwoven and randomly placed. This tissue allows the tissues to sustain tension from different directions. Located in the dermis, the deep skin layer.
     • consists of loose connective tissue and dense connective tissue cells. Cells are mainly spread apart
   • Cells
     • Mast Cells
       • Release heparin, which prevents blood clotting and releases histamine, which aids in the inflammatory response.
     • Macrophages
       • Clear foreign particles from tissues by phagocytosis. Functions as scavengers
     • Fibroblasts
       • Usually cells are far apart and they divide. They bind structures, support, and protect, store fat, produce blood cells, and repair tissue damage/ They produce fibers by secreting proteins into the matrix.

4. Epithelial

   • Transitional Epithelium
     • many layers of irregular shaped cells, cube shaped and elongated
     • found in inner lining of bladder, ureters, and parts of the urethra
     • protection, and able to respond to tention
   • Stratified Squamous Epithelium
     • found in throat, anal cavity, vagina, and oral cavity
     • single layer of thin, flattened cells
     • accumulate keratin, protection
   • Stratified Columnar Epithelium
     • protection and secretion
     • found in vas deferens, male urethra, and parts of the pharynx
     • several cell layers, top layer of elongated cell, cube shaped and in deeper layers
   • Stratified Cuboidal Epithelium
     • protection, secretion
     • found in mammary glands, sweat glands, salivary glands, and the pancreas
     • cubed shape cells occur in 2-3 layers
   • Glandular Epithelium
     • Glands
       • Exocrine
         • Holocrine
           • gland that releases entire cells
         • Merocrine
           • releases fluid products by exocytosis
         • Apocrine
           • glands that release entire cell bodies
       • Endocrine
       • can be found in salivary glands, sweat glands and endocrine glands
   • Pseudo stratified Columnar Epithelium
     • secretion of mucus
     • single layer of elongated cells arranged in more than one layer of cells that have different heights, rest on the basement membrane
     • Trachea, Upper Respiratory Tract, male vas deferens
   • Simple Squamous Epithelium
     • Found in Alveoli and capillaries of the lungs where gas exchange occurs, kidney glomerulus and tubules
     • Filtration, Diffusion, Osmosis, protects body surfaces
     • arranged as a single layer of flat cells that are in contact with basement membrane
   • Simple Cuboidal Epithelium
     • Found in salivary glands, thyroid follicles, and kidney tubules
     • secretion and absorption
     • arranged in a single layer of cube shaped cells that are in contact with the basement membrane
   • Simple Columnar Epithelium
     • single layer of elongated, column shaped cells
     • Found in digestive tract, small/large intestine, uterus, upper respiratory tract, fallopian tubes
     • secretion, digestion
   • membranous tissue covering internal organs and other internal surfaces of the body