TissuesA. Tissue – a grouping of cells that are

similar in structure and perform a common or related function

B. Histology – the study of tissues; requires a microscope

C. 4 basic types1.  Epithelial tissue (epithelium)2.  Connective tissue3.  Nervous tissue4.  Muscle tissue

TissuesD. Epithelium

1. FunctionsA) ProtectionB) AbsorptionC) FiltrationD) ExcretionE) Secretion

Tissues2. General Categories

A) Lining & covering epitheliumB) Glandular epithelium

3. Characteristics of epitheliumA) Cellularity – almost entirely cellsB) Polarity

1) Apical border

Tissues2) Basement membrane

C) Connective tissue supportD) Innervated but avascularE) Highly reproductive

4. Classification – many types named according to the number of cell layers and the cell’s shape

TissuesA) Number of cell layers

1) Simple2) Stratified

B) Cell’s shape1) Squamous2) Cuboidal3) Columnar

TissuesC) Types of epithelium

1) Simple squamousa) Lines the

systemic capillaries, glomeruli in the kidneys & alveoli in the lungs

b) Filtration, absorption & secretion

Tissues2) Stratified

squamousa) Nonkeratinized

i) Lines the mouth, esophagus & vagina

ii) Protection

Tissuesb) Keratinized

i) Makes up the epidermis of skin

ii) Protection3) Simple cuboidal

a) Found in the kidney tubules & secretory ducts of small glands

Tissuesb) Secretion &

absorption4) Simple columnar

– may be ciliated & contain goblet cellsa) Lines the

majority of the digestive tract

Tissuesb) Absorption,

secretion of mucus & enzymes, propulsion

5) Transitionala) Lines the ureters,

bladder & parts of urethra

b) Can be compressed without damage providing protection

Tissues6) Pseudostratified

columnar – may be ciliated & have goblet cellsa) Found in portions

of respiratory tract (trachea & bronchi)

b) Secretion & propulsion of mucus

TissuesE. Connective Tissue

1. CharacteristicsA) Common origin

1) MesenchymeB) Varying vascularityC) Extracellular matrix

Tissues2. Structural components

A) Ground substance – fills space between cells and contains the protein fibers

B) Protein fibers – provide support & flexibility1) Collagen fibers2) Elastic fibers3) Reticular fibers

TissuesC) Cells

1) Fibroblasts – connective tissue proper

2) Chondrocytes – cartilage3) Osteocytes – bone or osseous tissue

4) Hemocytes – blood5) Adipocytes – adipose

3. Types of Connective Tissue

TissuesA) Areolar (loose)

connective tissue1) All 3 fiber types2) Most widely

distributed CT in body

3) Serves to hold organs together while allowing movement

TissuesB) Dense regular connective tissue1) Collagen fibers

dominate – very strong

2) Run in a parallel arrangement

3) Strength dependent on direction of force

4) Forms tendons and ligaments

TissuesC) Dense irregular

connective tissue1) Collagen fibers

dominate but in an irregular arrangement

2) Strength in multiple directions

3) Dermis of skin, joint capsules

TissuesD) Adipose (fat)

tissue1) Scanty matrix2) Highly vascular3) Serves

protective function (cushioning organs), prevents heat escape, energy storage

4) Under skin, around kidneys, in breasts

TissuesE) Cartilage – 3 types

1) Hyaline cartilagea) Large number

of collagen fibersb) Chondrocytes

within lacunaec) End of long

bones, nose, trachea & larynx

Tissues2) Elastic cartilage

a) Almost identical to hyaline but with increased elastic fibers

b) Support with great flexibility

c) Outer ear & epiglottis

Tissues3) Fibrocartilage

a) Alternating rows of chondrocytes and collagen fibers

b) Has great compression abilities and resist tension

c) Intervertebral discs & menisci of the knee

TissuesF) Bone (osseous

tissue)1) Similar to

cartilage in structure but more collagen fibers and the presence of calcium salts (make bone hard)

2) Osteoblasts & osteocytes in lacunae

TissuesG) Blood

1) Matrix = plasma2) Fibers are

soluble and seen only during clotting

3) Functions in transport and protection

TissuesF. Nervous Tissue

1. Neurons – generate & conduct impulses

2. Neuroglial cells (neuroglia) – non-conducting cellsA) provide

support for neurons

TissuesG. Muscle Tissue

1. Composed of muscle fibers (cells) containing myofilamentsA) protein fibers that function in contraction

2. Functions primarily for movement3. Three types

TissuesA) Skeletal

1) Striated (striped) appearance

2) Multinucleated3) Voluntary4) Makes up all

skeletal muscles

TissuesB) Smooth

1) Non-striated appearance

2) Mononucleated3) Involuntary4) Found around

the hollow organs and structures of the body (except heart)

TissuesC) Cardiac

1) Striated appearance with prominent intercalated discs

2) Mononucleated3) Branching4) Involuntary5) Found only in

the heart