Chapter 5 Key Terms 1 TendonOsteocytes ErythrocytesLigaments AxonDendrites LeukocytesPeritoneum VisceralParietal PleuraPericardium AxonAdipose Elastic CartilageHyaline Cartilage

ANATOMY & PHYSIOLOGY CHAPTER 5: TISSUES 2

Tissues  A group of specialized cells that work together to perform a specific function  The basic unit of a tissue is a cell  The tissue is classified based on how the cells are arranged  Histology – study of tissues  4 types of tissues:  Epithelial, connective, muscle, nervous 3

Epithelial Tissue  Characteristics  Cells are tightly packed together  Lacks a rich blood supply  Reproduce rapidly  Good nerve supply  Epithelial tissue covers a surface or lines a cavity 4

Epithelial Tissue  Four functions: 1. Protects underlying tissues 2. Absorbs 3. Secretes 4. Excretes  Anchored to the basement membrane and cells around it  Named according to shape and number of layers 5

Epithelial Tissue  Named according to shape  Squamous: protection  Cuboidal: protection and secretion  Columnar: secretion and absorption 6

Epithelial Tissue  Named according to layers  Simple: 1 cell layer  Stratified: several layers  Pseudostratified: appears to be several layers, but is not  Transitional: several layers of easily stretched cells 7

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Epithelial Tissue  Can also be named based on function  Mucous membrane  Lines all cavities that open to the outside of the body (digestive, respiratory, urinary, reproductive tracts)  Often ciliated  Protects, absorbs nutrients, and secretes mucus, enzymes and bile salts 9

Epithelial Tissue  Glandular Epithelium  Exocrine Glands  Have excretory ducts that lead from the gland to the surface of the skin  Simple Exocrine Glands: single unbranching ducts  Ex. Sweat glands, sebaceous glands  Compound Exocrine Glands: branching ducts  Ex. Salivary glands 10

Epithelial Tissue  Endocrine Glands  Ductless glands that secrete hormones  Ex. Thyroid gland, pituitary gland  Goblet Cells  Unicellular gland that secretes mucus  Scattered throughout the epithelial cells that make up mucous membrane 11

Epithelial Tissue  Endothelium  Special epithelium that mainly lines the circulatory system  Usually a simple squamous arrangement of cells  Capillaries consist of 1 layer of endothelium  Endocardium  Endothelium that lines the inner parts of the heart 12

Epithelial Tissue  Mesothelium (AKA Serous Tissue)  Lines the large cavities of the body that do not open to the outside  Simple squamous layer overlying connective tissue  Pleura: serous membrane that lines the thoracic cavity  Pericardium: serous membrane that covers the heart  Peritoneum: serous membrane lining abdominal cavity  This type of tissue helps reduce friction between organs 13

Connective Tissue  Allows movement and provides support for other types of tissues  Has abundance of extracellular fluid called matrix  Contains collagen and elastin fibers embedded in matrix  3 types:  Loose connective  Dense connective  Specialized connective 14

Loose Connective Tissue  Fibers are not tightly woven among themselves  3 types of loose connective tissue:  Areolar  Adipose  Reticular 15

Loose Connective Tissue  Areolar  Most widely distributed of the loose connective tissue  Easily stretches without tearing  3 main types of cells among its fibers  Fibroblasts: form fibrils  Histiocytes: also called macrophages  Mast cells: produce heparin and histamine  Basic support tissue around organs, muscles, nerves, 16

Loose Connective Tissue  Adipose  Loaded with fat cells  Large vacuole that contains stored fat  Nuclei and cytoplasm are pushed up against cell membrane  Act as protective packing around and between organs, muscle fibers, and nerves  Poor conductors 17

Dense Connective Tissue  Dense Regular Connective tissue  Consists of many closely packed collagenous fibers, a fine network of elastin fibers, and some cells (mainly fibroblasts)  Lack good blood supply  Ligaments: attach bone to bone  Tendons: attach muscle to bone  Aponeuroses: wide, flat tendons 18

Dense Connective Tissue  Dense Irregular Connective Tissue  Collagen fibers are thicker and more randomly organized  Allows tissue to sustain tension exerted from many directions  Dermis layer of the skin  Fascia: covering of a muscle 19

Specialized Connective Tissue  Cartilage  Cells are called chondrocytes (chondro = cartilage)  Found in cavities called lacunae  Various amounts of collagen and elastin fibers embedded in matrix cause cartilage to be either flexible or very rigid  3 types of cartilage found in the body 20

Specialized Connective Tissue  Hyaline Cartilage  Has very fine collagen fibers  Found at ends of long bones  Fetal skeletal is entirely hyaline cartilage for first several months  Ossification (process of bone replacing cartilage) occurs over the next several months until baby is born  Found in trachea, bronchi, septum in nose, costal cartilage that connects ribs to sternum 21

Specialized Connective Tissue  Fibrocartilage  Dense and resistant to much stretching (very tough)  Contains many collagenous fibers  Functions as a shock absorber  Found in intervertebral disks and knees 22

Specialize Connective Tissue  Elastic Cartilage  Abundance of elastin fibers  These fibers allow this cartilage to be easily stretched  Framework for external ear and parts of larynx 23

Specialized Connective Tissue  Bone  Most rigid connective tissue  Made up of compact bone and cancellous/spongy bone  Matrix has abundance of mineral salts  Good blood supply  Osteocytes  Bone cells 24

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Special Connective Tissue  Blood and hematopoietic tissue  Unique in that it is composed of a fluid portion and the cells  Erythrocytes  Red blood cells  Leukocytes  White blood cells  Transports substances to body 26

Muscle Tissue  Its characteristic ability is its ability to contract  Often referred to as a muscle fiber because they are very long and cylindrical  Smooth Muscle  Cells are spindle shaped  Usually involuntary/controlled by autonomic nervous system  Lack striations: work slowly and rhythmically  Peristalsis: movement of food down esophagus 27

Muscle Tissue  Skeletal/striated muscle  Voluntary muscle (controlled by conscious effort)  Cells are long and cylindrical  Allows you to react quickly, but also fatigue quickly  Striations are caused by alternating light and dark bands within the muscle  Light bands = actin  Dark bands = myosin 28

Muscle Tissue  Cardiac Muscle  Only found in the heart  Involuntary  Connected to each other by intercalated disks  The branches of this tissue allow for simultaneous pumping of the heart  Pumps blood throughout the body 29

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Nervous Tissue  Neuron  Nerve cell (sometimes called nerve fibers because of length)  Long cells that carry electrical impulse along its axon  Live a long time because they are amitotic  Purposes are to detect environment, coordinate activities, thinking, memory, emotions, logic  Makes up brain, spinal cord, and nerves of the body 31

Nervous Tissue  Cell body: contains the nucleus  Dendrite: connect to other cells  Receive stimuli from other cells and conduct them to body  Axon: long extension of cell body  Axon Ending: Connects to other cells 32