Chapter 5 Tissues

5 - 2 Cell Review A. 75 trillion cells, various shapes & sizes B. Differences in shape make different functions possible A.includes many different cell structures B.three main parts -nucleus, cytoplasm, cell membrane C. specialized organelles w/ specific functions

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5 - 4 Cell Differentiation 1. Process by which cells develop into different types of cells w/ specialized functions 2. Reflects genetic control of the nucleus as certain genes are turned on & others are turned off

5 - 5 u Tissues: A. Cells w/ common structures are arranged in tissues that serve specific functions B. four major types Epithelial tissue Connective tissue Nervous tissue Muscle tissue C. Arise from 3 embryonic germ layers Endoderm Mesoderm Ectoderm

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5 - 8 A tissue may be held together by a sticky extra cellular matrix that coats the cells or weaves them together in a fabric of fibers

5 - 9 u Epithelial Tissues: 9 types 1. covers organs, line body surfaces, cavities & hollow organs 2. anchored to a basement membrane 3. tightly packed cells w/ prominent nuclei 4. generally lack blood vessels 5. replaced frequently 6. functions: protection, secretion, absorption, excretion, sensory reception

Simple 1 layer Stratified more than 1 layer

Simple Squamous Epithelium 1. 1 layer of thin, flattened scale like cells 2. suited for diffusion: found in the lungs, lines blood & lymph vessels & body cavities

Stratified Squamous Epithelium 1. layers of flattened cells designed to protect underlying layers 2. outer layer of skin, lines the mouth, throat, vagina, & anal canal 3. cells undergo keratinization; except for where tissues remain moist: throat, vagina, anal canal

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Simple Cuboidal Epithelium 1. 1 layer of cube-shaped cells w/ centrally located nuclei 2. functions: secretion & absorption in the kidneys, & secretion in glands

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Stratified Cuboidal Epithelium 1. 2 or 3 layers of cuboidal cells lining a lumen of the mammary glands, sweat glands, salivary glands, & pancreas 2. Several layers provide greater protection

Simple Columnar Epithelium 1. row of elongated cells, nuclei located near basement membrane, may be ciliated (move substances) 2. lines the uterus, stomach, & intestines, protects underlying tissues, secretes digestive fluids, & absorbs nutrients

In the intestine, these cells possess microvilli to increase surface area for absorption 4. can contain mucus-secreting goblet cells

Stratified Columnar Epithelium 1. several layers of cells found in the vas deferens, part of the male urethra, & parts of the pharynx.

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Pseudostratified Columnar Epithelium 1. appear layered due to the varying positions of their nuclei, but are not layered 2. may have cilia & globlet cells, line & sweep debris from respiratory tubes

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Transitional Epithelium 1. designed to distend & return to normal size, ex. the lining of the bladder 2. provides distensibility & keeps urine from diffusing back into the internal cavity

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Glandular Epithelium 1. designed to produce & secrete substances into ducts or into body fluids 2. Glands that secrete products into ducts (inside & outside) are exocrine; those that secrete into body fluids (i.e. blood) are endocrine 3. Glands are classified by the ways the glands secrete their products

a. Merocrine release products by exocytosis (pancreas) & are grouped as serous which produce a watery fluid or mucus which produce a thicker, protective substance. b. Apocrine glands lose portions of their cell bodies during secretion (mammary glands) c.Holocrine glands release entire cells (sebaceous glands)

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u Connective Tissues: 1.bind, support, protect, serve as frameworks, fill spaces, store fat, produce blood cells, protect against infection, and repair tissue damage 2.have abundant matrix, or intercellular material throughout, & have good blood supplies (except cartilage)

Connective Tissue Fibers 1. Strong collagenous fibers (white) made of the protein collagen, add strength for holding body parts together 2. Elastic fibers (yellow), made of the protein elastin, are stretchy & add flexibility 3. Reticular fibers are thin collagenous fibers that form supportive networks in a variety of tissues

Major Cell Types 1. Fibroblast most common, a fixed star- shaped cell, large in size & secretes fibers 2. Wandering macrophages function as scavenger cells & defend against infection 3. Mast cells are large, located near blood vessels where they release heparin (anticoagulant) & histamine (promotes inflammation)

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Loose Connective (areolar) Tissue 1. forms thin membranes throughout the body that bind body parts together such as skin & underlying organs 2. mostly fibroblasts separated by a gel- like ground substance containing loosely packed collagenous & elastic fibers

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Adipose Tissue 1. loose connective tissue stores fat 2. beneath the skin, around joints, padding the kidneys & other internal organs, in certain abdominal membranes

Dense Connective Tissue 1. densely packed collagenous fibers, very strong but lacks good blood supply 2. part of tendons & ligaments

Elastic connective tissue abundant in elastic fibers some collagenous fibers fibroblasts walls of large arteries, airways, heart

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u Reticular connective tissue composed of reticular fibers supports walls of liver, spleen, lymphatic organs

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Cartilage 1. rigid connective tissue, provides a supportive framework for various structures lacks a vascular system (heals slowly) 2. Cartilage cells (chondrocytes) lie within lacunae in the gel-like fluid matrix 3. enclosed within a connective tissue perichondrium

Hyaline cartilage, most common, white with abundant fine collagen fibers, found at the ends of bones, supports respiratory passages

Elastic cartilage, with elastic fibers, provides a flexible framework for the external ears & parts of the larynx

Fibrocartilage, with many collagenous fibers, tough tissue that provides a shock- absorbing function in intervertebral disks, knees & pelvic girdle

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Bone 1. rigid connective tissue, w/ deposits of mineral salts & collagen within the matrix 2. supports the body, protects, forms muscle attachments, site for blood cell formation 3. has a good blood supply, enabling rapid recovery after injury 4. Osteocytes arranged in concentric circles around a central canal

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Blood 1. cells suspended in liquid matrix, plasma 2. transports substances thru the body 3. 2 types of cell : Red & White

Muscle Tissues: Muscle cells, fibers, can contract 3 major types: skeletal, cardiac & smooth

Skeletal Muscle Tissue 1. attached to bone, can be controlled by conscious effort (voluntary) 2. long & cylindrical, striated, have many nuclei, contract from nervous impulse

Smooth Muscle Tissue 1. lacks striations, 1 nuclei, spindle- shaped cells (tapered) 2. involuntary, found in the walls of internal organs, digestive tract, blood vessels, & urinary bladder

Cardiac Muscle Tissue 1. in the heart, branching fibers connected via intercalated disks 2. involuntary, single nucleus, striated

Nervous Tissues: 1. in the brain, spinal cord, nerves 2. Neurons conduct impulses 3. helper cells, neuroglia, support & nourish neurons

 Types of Membranes u Serous u Mucous u Synovial u Cutaneous/ Integumentary

A. Serous membranes line body cavities that lack openings to the outside 1. line the thorax & abdomen and cover the organs within these cavities 2. epithelial & connective tissue 3. secrete serous fluid that acts as a lubricant

B. Mucous membranes line the cavities & openings that lead to the outside of the body including the oral and nasal cavities, and openings of the digestive, reproductive, respiratory, and urinary systems 1. epithelium & connective tissue 2. w/ specialized cells that secrete mucus

C.Synovial membranes line joint cavities 1. only connective tissues 2. lubricating synovial fluid D.Cutaneous membrane consists of the skin 1. epithelial & connective tissues

Practice Tissue ID

Simple Squamous Epithelium Stratified Epithelium Pseudostratified Epithelium Simple Cuboidal Epithelium

Bone Dense Fibrous, Collagenous Areolar Connective Tissue Reticular

Adipose Tissue Blood Nervous Tissue Hyaline Cartliage

Skeletal Muscle Smooth Muscle Cardiac Muscle

Clinical Application Collagen Disorders Chondrodysplasia collagen chains too wide stunted growth deformed joints Dystrophic epidermolysis bullosa breakdown of collagen that attaches skin layers stretchy skin lax joints Hereditary osteoarthritis change in amino acid in collagen painful joints 5-25

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