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TISSUE
is a group of cells of similar type that work together to serve a common function.
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HUMAN tissues come in four PRIMARY types:
Epithelial tissue; Connective tissue; Muscle tissue, and; Nervouse tissue
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EPITHELIAL Tissue
Covers body surfaces, lines body cavities and organs, and forms glands.
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CONNECTIVE Tissue
serves as storage site for fat, plays an important role in immunity, and provides the body and its organs with protection and support.
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MUSCLE Tissue
is responsible for body movement and for movement of substances through the body.
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NERVOUS Tissue
conducts nerve impulses from one part of the body to another.
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TWO characteristics of EPITHELIAL Tissue are:
FREE Surface and BASEMENT Membrane.
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FREE SURFACE (characteristic of EPITHELIAL)
may be specialized for PROTECTION, SECRETION, or ABSORPTION.
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BASEMENT MEMBRANE (characteristic of EPITHELIAL)
is a non-cellular layer THAT BINDS the epithelial cells to underlying connective tissue and, helps the epithelial tissue RESIST STRETCHING.
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3 BASIC SHAPE OF EPITHELIAL CELLS are suited to functions. They are:
SQUAMOUS; CUBOIDAL, AND ; COLUMNAR
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SQUAMOUS Epithelium
is made up of flattened, or scale-like, cells. These cells form linings--inthe blood vessels or lungs, for instance--where their flattened shape allows oxygen and carbon dioxide to diffuse across the lining easily. In blood vessels, the smooth surface of the blood vessel lining reduces friction.
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CUBOIDAL Epithelium
is made up of cube-shaped cells. Cuboidal cells are found in many GLANDS and in the LINING of KIDNEY tubules, where they PROVIDE some PROTECTION and are specialized for SECRETION and ABSORPTION.
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COLUMNAR Epithelium
consisting of elongated, column-shaped cells, have numerous small, fingerlike folds on their exposed surfaces, greatly increasing the surface area for absorption. The goblet cells of this lining produce mucus to ease the passage of food and protect teh cells of the lining.
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SIMPLE Epithelial Tissue
a single layer of cells.
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STRATIFIED Epithelial Tissue (multiple layers of cells)
serves a protective role, because its multiple layers provide additinal thickness that makes it more difficult for molecules to pass through
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a GLAND...
is epithelial tissue that secretes a product.
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Types of GLANDS
Exocrine Glands and Endocrine Glands
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EXOCRINE Glands
secrete their products into ducts leading to body surfaces, cavities, or organs. Ex. of it is the glands that produce DIGESTIVE ENZYMES, MILK GLANDS, and the OIL and SWEAT GLANDS of the skin.
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ENDOCRINE Glands
lack ducts and secrete their products, hormones, into spaces just outside the cells. Ultimately, hormones diffuse into the bloodstream and are carried thoughout the body.
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CONNECTIVE TISSUE
the body's glue; common role is to bind (tendons and ligaments) and support the other tissue (cartilage and bone). Transporter of blood and Energy storage (adipose tissue). It is the most abundant and widely distributed tissue in the body. All connective tissue contain cells embedded in an exracellular MATRIX.
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Connective-Tissue MATRIX
consists of protein fibers and noncellular material called GROUND SUBSTANCE.
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GROUND SUBSTANCE
may be solid (as in bone), fluid (as in blood), or gelatinous (as in cartilage).
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3 Protein Fibers of Connective-Tissue MATRIX
Collagen fibers; Elastic fibers, and; Reticular fibers.
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COLLAGEN FIBERS
are strong and ropelike and can withstand pulling because of their great tensile strength.
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ELASTIC FIBERS
contain random coils and can stretch and recoil like a spring. Common in structures where great elasticity is needed, including the SKIN, LUNGS, and BLOOD VESSELS.
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RETICULAR FIBERS
are thin strands of collagen that branch extensively, forming interconnecting networks suitable for supporting soft tissues (for ex.: they support the liver and spleen).
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FIBROBLASTS
produced (in the connective tissue) all the three types of PROTEIN FIBERS (collagen, elastic, and reticular) and also repair tears in body tissue.
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Connective Tissue Proper
LOOSE and DENSE connective tissues differ in teh ratio of cells to extracellular fibers.
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LOOSE Connective Tissue
contains many cells but has fewer and more loosely woven fibers that are seen in the matrix of dense connective tissue. Ex: AREOLAR and ADIPOSE
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AREOLAR (Loose) Connective Tissue
functions as universal packing material between other tissues; embedded in a gelatinous matrix that is soft and easily shaped; found between muscles where it permits one muscle to move freely over another; anchors the skin to underlying tissues and organs.
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ADIPOSE (FAT) Connective Tissue
contains cells that are specilized for fat storage.
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DENSE Connective Tissue
forms strong bands because of its large amount of tightly woven fibers. it is found in LIGAMENTS (structures that join bone to bone), TENDONS (structures that join muscle to bone), and the DERMIS (layer of skin below the epidermis).
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Specialized Connective Tissue
comes in three types: CARTILAGE, BONE, and BLOOD
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CARTILAGE
tough and flexible tissue; serves as cushioning between certain bones and helps maintain the structure of certain body parts, including the ears and nose; lacks blood vessels and nerves;
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CHONDROCYTES
a cells in cartilage that sits within spaces in the matrix called LACUNAE.
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3 types of CARTILAGE
HYALINE cartilage, ELASTIC cartilage, and FIBRO cartilage
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HYALINE Cartilage
the most abundant, provides support and flexibility; contains numerous cartilage cells in matrix of collagen fibers and bluish white, gel-like ground substance; commonly known as GRISLE; located at the ends of long bones, where it allows one bone to slide easily over another; also forms part of the NOSE, RIBS, LARYNX, and TRACHEA.
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ELASTIC Cartilage
is more flexible than hyaline cartilage bcoz of the large amounts of wavy elastic fibers in its matrix; found in external EAR, where it provides strength and elasticity.
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FIBRO Cartilage
contains fewer cells than either hyaline or elastic cartilage; like hyaline cartilage, its matrix contains collagen fibers; forms a cushioning layer in the knee joint as well as the outer part of the shock-absorbing disks between the vertebrae of the spine; it is made withstand pressure.
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BONE
in combination w/ cartilage and other components of joints, makes up the skeletal system; is a living, actively metabolizing tissue w/ a good blood supply that promotes prompt healing.
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BONE functions:
protection and support for internal structures; movement, in conjunction w/ muscles; storage of lipids (in yellow marrow), calcium, and phosphorus; and production of blood cells (in red marrow).
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BLOOD
consisting of a liquid matrix, called PLASMA , in which so-called formed elements (cells and cell fragments called PLATELETS) are suspended; found w/in blood vessels; transports nutrients, gases, hormones, wastes; fights infections.
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IMPORTANT function of BLOOD is:
to transport various substances, many of which are dissolved in the plasma.
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Kinds of FORMED ELEMENTS
RBC (Red Blood Cells), WBC (White Blood Cells), and PLATELETS
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RBC (Red Blood Cells)
transport oxygen to cells and also carries some of the carbon dioxide away from cells.
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WBC (White Blood Cells)
helps fight infection.
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PLATELETS
helps with blood clotting.
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MUSCLE Tissue
is composed of muscle cells (or, muscle fibers) that contract when stimulated.
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3 Types of Muscle Tissue
- 1. Skeletal
- 2. Cardiac
- 3. Smooth
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SKELETAL Muscle Tissue
is usually attached to bones; under conscious control, it is described as VOLUNTARY MUSCLE; long, cylindrical-shaped cells, each containing several nuclei; have striations, which are alternating light and dark bands visible under a light microscope.
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STRIATIONS
are caused by the orderly arrangement of the contractile proteins actin and myosin, w/c interact to cause muscle contraction.
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CARDIAC Muscle Tissue
is found ONLY in the WALLS of the HEART, where its contractions are responsible for pumping blood to the rest of the body; considered INVOLUNTARY MUSCLE; resemble branching cylinders and have striations and typically only one nucleus.
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SMOOTH Muscle Tissue
is a VOLUNTARY muscle and is found in the walls of blood vessels and airways, where its contraction reduces the flow of blood or air; also found in the walls of organs such as: stomach, intestines, and bladder, where it aids in mixing and propelling good through the digestive tract and in eliminating waste; contains single nucleus, and lacks striations.
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NERVOUS Tissue
makes up the nervous system: BRAIN, SPINAL CORD, and NERVES. Consists of TWO general cell types: NEURONS and NEUROGLIA (accessory cells)
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NEURONS
generate and conduct nerve impulses, w/c they conduct to other neurons, muscle cells, or glands; have three (3) parts: cell body, dendrites, and an axon.
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Parts of NEURONS
- 1. Cell Body
- 2. Dendrites
- 3. Axon
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Cell Body
houses the nucleus and most organelles.
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Dendrites
are highly branched processes that provide a large surface area for the reception of signals from other neurons.
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Axon
a long extension that usually conducts impulses away from the cell body.
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NEUROGLIA (or: glial cells)
support, insulate, and protect neurons; increase rate at w/c impulses are conducted by neurons and provide neurons w/ nutrients from nearby blood vessels.
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3 Kinds of Junctions (between cells)
- 1. Tight Junctions
- 2. Adhesion Junctions
- 3. Gap Junctions
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Tight Junctions
- * creates an impermeable junction that prevents the exchange of materials betweens cells.
- * found between epithelial cells of the digestive tract, where they prevent digestive enzymes and micro organisms from entering the blood.
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Adhesion Junctions
- * Holds cells together despite stretching.
- * Found in tissues that are often stretched, such as the skin and the opening of the uterus.
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Gap Junctions
- *Allow cells to communicate by allowing small molecules and ions to pass from cell to cell.
- *Found in epithelia in w/c the movement of ions coordinates functions, such as the beating of cilia; found in excitable tissue such as heart and smooth muscle.
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Intergumentary System
- *Protects underlying tissues
- *Provides skin sensation
- *Helps regulate body temp.
- *Synthesizes vitamin D
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Skeletal System
- *Attachment for muscles
- *Protects organs
- *Stores calcium and phosphorous
- *Produces blood cells
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Muscular System
- *Moves body and maintain posture.
- *Internal transport of fluids.
- *Generation of heat.
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Nervous System
Regulates and integrates body functions via neurons.
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Endocrine System
Regulates and integrates body functions via hormones.
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Cardiovascular System
- *Transport nutrients, respiratory gases, wastes, and heat.
- *Transport immune cells and antibodies.
- *Transport hormones.
- *Regulates pH.
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Lymphatic System
- *Returns tissue fluids to bloodstream.
- *Protects against infection and disease.
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Respiratory System
Exhanges respiratory gases with the environment.
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Digestive System
- *Physical and chemical breakdown of food.
- *Absorbs, processes, and stores food.
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Urinary System
Maintains constant internal environment through the excretion of nitrogenous waste.
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Reproductive System
- *Produces and secretes hormones.
- *Produces and releases egg and sperm cells.
- *Houses embryo/fetus (females only).
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an ORGAN
is a structure composed to two or more different tissues that work together to perform a specific function
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Body Cavities
- *Protect the vital organs from being damaged.
- *Allow organs to slide past one another and change shape.
- *Two main body cavities: Ventral and Dorsal
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the VENTRAL Cavity
- *Thoracic (chest)
- *Abdominal
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Thoracic Cavity
- *Pleural Cavity, house the LUNGS and;
- *Pericardial Cavity, which holds the HEART.
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Abdominal Cavity, contains the:
- *Digestive System
- *Urinary System
- *Reproductive System
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Diaphragm
a muscle sheet that separate the Thoracic and Abdominal cavities.
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Dorsal Cavity
- *Cranial Cavity, w/c encloses the BRAIN, and,
- *Spinal Cavity, w/c houses the SPINAL CORD.
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BODY CAVITIES and ORGAN surfaces are covered with membranes--sheets of epithelium supported by connective tissues.
Membranes form physical barriers that protect underlying tissues. The body has 4 types of membranes: MUCOUS, SEROUS, SYNOVIAL, and CUTANEOUS.
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Mucous Membranes
line passage ways that open to the exterior of the body, such as those of the respiratory, digestive, reproductive, and urinary system.
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Serous Membranes
line the Thoracic and Abdominal cavities and the organs w/in them. They secrete a fluid that lubricates the organs w/in these cavities.
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Synovial Membranes
line the cavities freely movable joints, such as the knee. These membranes secrete a fluid that lubricates the joint, easing movement.
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Cutaneous Membrane, or SKIN
covers the outside of the body. Unlike other membranes, it is thick, relatively waterproof, and relatively dry; has two principal layers: EPIDERMIS & DERMIS
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Epidermis
thin, outer layer, forms a protective barrier against environmental hazards.
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Dermis
inner layer, contains blood vessels, nerves sweat and oil glands, duct of sweat glands, sensory structures, and hair follicles.
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Hypodermis or Subcutaneous Layer
a layer of loose connective tissue which anchors the skin to the tissues of other organ systems that lie beneath the skin.
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Melanin
a pigment; is produced by cells called melanocytes at the base of the epidermis
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Two Kind of Melanin (pigment)
- * yellow-to-red form
- * black-to-brown form
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ALBINISM
is an inherited condition in which an individual's melanocytes are incapable of producing melanin.
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VITILIGO
is a condition in w/c melanocytes disappear either partially or completely from certain areas of the skin, leaving white patches in their wake.
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Three Components of Momeostatic
- 1. Receptor
- 2. Control Center
- 3. Effector
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Receptor
detects change in the internal or external environment. A receptor , in this context, is a sensor that monitors the environment. When the receptor detects a change in some factor or event--some variable--it sends that information to the control center.
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Control Center
determines the factor's set point--the level or range that is normal for the factor in question. The control center integrates information coming from all the pertinent receptors and selects an appropriate response. In most of the body's homeostatic systems, the control center is located in the brain.
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Effector
often a muscle, or gland, carries out the selected response.
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Hypothalamus
the body's temperature control center.
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