Chapter 5: Tissues

Introduction Tissue: Four types (Table 5.1): Def – cells organized into groups and layers all with the same function Rely upon extracellular matrix (contains nutrients needed for cells to thrive, transmits signals) Four types (Table 5.1): 1) Epithelial 2) Connective 3) Muscle 4) Nervous

Epithelial Tissue Location Function Characteristics Lines exposed surfaces of body Forms inner lining of body cavities Covers organs Function Protection, absorption, secretion Characteristics One side is exposed, one side is anchored to basement membrane (connective tissue) Tightly packed cells with little to no blood vessels Readily divide

Connective Tissue Location Function Characteristics Throughout body (bone, blood, cartilage) Function Support and protection, binds structures, fills spaces, stores fat, produce blood cells, protect against infection, repair tissue damage Characteristics Cells have spaces between them filled with extracellular matrix Can usually divide and have good blood supply Can be flexible or rigid in nature

Muscle Tissue Location Function Characteristics Throughout body (skeletal muscles, heart muscle, muscles in tracts and tubes) Function Provide movement Characteristics Cells can shorten Contract/relax in response to stimuli

Nervous Tissue Location Function Characteristics Brain, spinal cord, and nerves throughout body Function Transmit signals across body Coordinate, regulate, integrate body functions Characteristics Respond to changes in their surroundings Basic cell :neuron

Epithelial Tissue Classification Classified by shape and # of layers Shape Squamous Cubiodal Columnar # of Layers Simple- one layer Stratified- multiple layers

Simple Squamous Form Function Locations Single layer, flattened, tile- like cells Tightly packed Easily damaged Function Diffusion (substances pass through easily) and filtration Locations Alveoli in lungs Capillaries

Simple Cuboidal Form Function Location Single layer cube-shaped cells Central nucleus Function Secretion and absorption Location Lining of kidney tubules Lining of some gland ducts (thyroid, salivary, pancreas, liver) Covers ovaries

Simple Columnar Form Function Location Single layer elongated, column-like cells Can be ciliated Goblet cell scattered Function Protection, secretion, and absorption Location Lining of digestive tract Female reproductive tubes (cilia aid in egg movement)

Pseudostratified Columnar Form Single layer elongated cells with nuclei at different heights, often ciliated Appear layered Goblet cells scattered Function Movement of particles Trap dust/microorganisms Location Lining of respiratory passages

Stratified Squamous Form Function Location Several layers of tile-like cells Thick Divide and push old cells up Function Protection (microorganisms) Keritinize (harden and die) providing layer to prevent water loss Location Outer layer of skin Linings of cavities opening to the outside

Stratified Cuboidal Form Function Location Several layers of cube- shaped cells Function Protection Location Linings of larger ducts of glands Ovary follicle

Stratified Columnar Form Function Location Several layers Outer layer elongated cells Function Protection and secretion Location Parts of pharynx Parts of male reproductive system

Transitional Form Function Location Several layers of rounded cell that can stretch to form layers of flattened cells Function Stretch Forms barrier to prevent diffusion of materials back Location Bladder Ureter Parts of urethra

Glandular Epithelium Function: secrete and produce Endocrine vs Exocrine Endocrine- released into interstitial fluid or bloodstream Exocrine- released into duct or onto surface Serous vs Mucous Serous- found in cavities closed to the inside Mucous- found in cavities with exposure to outside

Connective Tissue Cells Fibroblasts- fixed cells that secrete protein fibers Characteristics: Collagenous- thick threads with a high tensile strength but only a little elasticity Elastic- thin, networked thread; not as strong but elastic Recticular- thin delicate threads; forms framework in some organs Macrophages (histiocytes)- roaming cells that eat cellular debris and foreign particles by phagocytosis Mast cells- fixed cells that release heparin and histamine

Loose Connective Form Function Location Scattered cells and fibers in matrix Mainly fibroblasts Very low tensile strength Thin, delicate Function Binds organs together (especially skin to underlying organs) Location Beneath many epithelial layers including skin Between muscles

Adipose (fat) From Function Location Specialized form of loose connective where fat cells store enough fat to crowd other things out of the tissue Function Storage of energy (in fat), insulation, protection, cushion Location All throughout body Beneath skin, spaces in between muscles, around kidneys, behind eyes, surface of heart, around joints

Dense Connective Form Function Location Few cells, highly packed with thick collagenous fibers Very strong Few elastic fibers Function Binds organs together (muscle to bone, bone to bone) Protective layer of eye Location Tendons and ligaments Deep layers of skin Eye

Cartilage Form Cartilage cell (chondrocytes) surrounded with a gel-like matrix Rigid Function Supports Protects underlying tissue (cushions bones) Forms framework with some flexibility Provides attachment Location Ends of bones Ears Nose

Bone Form Function Location Bone cells (osteocytes) surrounded by rigid matrix of calcium carbonate and calcium phosphate salts Most rigid connective tissue Function Supports, protects, provides framework Muscle attachment Form blood cells Store/release inorganic chemicals Location Bones

Blood Form Function Location Cells suspended in plasma matrix Three types: RBCs, WBCs, plasma Function Transports materials (exchange of materials) Help maintain internal environment Location Blood

Muscle Tissue Location Function Characteristics Throughout body (skeletal muscles, heart muscle, muscles in tracts and tubes) Function Provide movement Characteristics Cells shorten

Muscle Tissue Types Skeletal Cardiac Smooth Voluntary, striated, multiple nuclei/cell Ex: Skeletal muscles (quadriceps, triceps) Cardiac Involuntary, striated, one nucleus/cell Ex: Heart muscle Smooth Involuntary, unstriated, one nucleus/cell Ex: Esophagus, stomach wall

Skeletal Muscle Tissue Form Long thread-like cells with banding, striations, along the length Cell w/ many nuclei Function Voluntary movements Talk, smile, swallow, breathe, sing, etc. Location Attached to bones

Cardiac Muscle Tissue Form Function Location Complex network of branching, striated cells connected by intercalated disks Function Movement of heart Involuntary movement Location Heart (only!)

Smooth Muscle Tissue Form Function Location Spindle-shaped cells lacking striations and poorly organized Function Movement of internal organs Involuntary movement Location Walls of internal organs (stomach, intestines, bladder, uterus, blood vessels

Nervous Tissue Location Function Characteristics Brain, spinal cord, and nerves throughout body Function Transmit signals (nerve impulses) across body Coordinate, regulate, integrate bodily functions Characteristics Respond to changes in their surroundings Basic cell: neuron

Nervous Tissue Types Neurons Neuroglial cells Basic cellular unit of nervous system Transmit the messages Senses environmental changes Neuroglial cells Support neurons Bind nervous tissue Supply nutrients to neurons

Types of Membranes Epithelial: 3 Types Connective Serous- release serous fluid and line cavities not exposed to the outside, lubricate membrane surface Mucous- release mucous and line cavities that open to outside (oral/nasal cavity, digestive/respiratory/ urinary/reproductive tubes) Cutaneous- skin Connective Synovial- lines joints