© 2015 Pearson Education, Inc. Body Tissues  Groups of cells with similar structure and function  Tissues are organized into organs  The shape and structure of the cells of tissues determines the function of the tissue  Four primary types: 1.Epithelial tissue (epithelium) 2.Connective tissue 3.Muscle tissue 4.Nervous tissue

© 2015 Pearson Education, Inc. 1. Epithelial Tissues  Epithelium- “covering”  Locations: body coverings, body linings, and glandular tissue  Functions: protection, absorption, filtration, secretion  Cells fit closely together and often form sheets

© 2015 Pearson Education, Inc.  There is always a free surface or side of the tissue called the apical surface  Avascular (no direct blood supply)  Regenerate easily if well nourished

© 2015 Pearson Education, Inc. Every epithelial tissue is given two names:  First word = Number of cell layers 1.Simple—one layer 2.Stratified—more than one layer

© 2015 Pearson Education, Inc.  Second word = Describes the shape of cells 1.Squamous: Flattened, like fish scales 2.Cuboidal: Cube-shaped, like dice 3.Columnar: Column-like

© 2015 Pearson Education, Inc. Simple Epithelia Simple squamous epithelium  Characteristics/Functions:  Single layer of flat cells  Forms membranes where filtration or exchange of substances by diffusion occurs  Locations within the body: 1.Air sacs of lungs 2.Walls of capillaries, 3.Forms serous membranes (the lining of the ventral cavity and covers organs in that cavity)

© 2015 Pearson Education, Inc.

Simple Epithelia Simple cuboidal  Characteristics/Functions:  Single layer of cube-like cells  Found in structures involved in secretion and absorption; ciliated types propel mucus or reproductive cells  Locations within the body: 1.Common in glands and their ducts (salivary glands and pancreas) 2.Forms the walls of kidney tubules 3.Covers the surface of ovaries

© 2015 Pearson Education, Inc.

Simple Epithelia Simple columnar  Characteristics/Functions:  Single layer of tall cells  structures involved in secretion and absorption; ciliated types propel mucus or reproductive cells;  Locations within the body: 1.Lines digestive tract from stomach to anus 2.Mucous membranes line body cavities opening to the exterior

© 2015 Pearson Education, Inc.

Simple Epithelia Pseudostratified columnar  Characteristics/Functions:  Single layer, but some cells are shorter than others giving a false (pseudo) impression of stratification  absorption or secretion; mucus produced by the cells trap dust and other debris and move it away from the lungs  Locations within the body:  Respiratory tract, where it is ciliated

© 2015 Pearson Education, Inc.

Stratified Epithelia Stratified squamous epithelium  Characteristics/Functions:  Named for cells present at the free (apical) surface, which are flattened  protective covering where friction is common  Locations within the body:  lining of the: 1.Skin (outer portion) 2.Mouth 3.Esophagus

© 2015 Pearson Education, Inc.

Stratified Epithelia Transitional epithelium  Characteristics/Functions:  Composed of modified stratified squamous epithelium  Cells can stretch and has the ability to return to normal shape  shape of cells depends upon the amount of stretching  Locations within the body:  urinary system organs (bladder, ureters)

© 2015 Pearson Education, Inc.

2. Connective Tissue  Found everywhere in the body  The most abundant tissues  Functions:  Provides protection  Binds body tissues together  Supports the body

 They range from being avascular to being well vascularized  Cells produce and secrete an extracellular matrix- nonliving material that surrounds connective tissue cells; ranges from being very hard to very soft and liquid; cells aren’t tightly packed like epithelial tissue

© 2015 Pearson Education, Inc.  From most rigid to softest extracellular matrix: 1.Bone 2.Cartilage 3.Dense connective tissue 4.Loose connective tissue 5.Blood

© 2015 Pearson Education, Inc. Bone  Characteristics:  Osteocytes (bone cells)  Surrounded by a hard matrix of calcium salts  Functions:  protect and support the body

© 2015 Pearson Education, Inc.

Cartilage  Characteristics:  Less hard and more flexible than bone  Found in only a few places in the body  Chondrocyte (cartilage cell) is the major cell type

© 2015 Pearson Education, Inc.

Dense connective tissue  Locations:  Tendons—attach skeletal muscle to bone  Ligaments—attach bone to bone at joints and are more elastic than tendons  Dermis—lower layers of the skin

© 2015 Pearson Education, Inc.

Loose connective tissue types 1. Areolar tissue  Most abundant connective tissue  Functions as a “glue” to hold organs in their proper place  Can store fluid and salts for surrounding tissues

© 2015 Pearson Education, Inc.

2. Adipose tissue (Fat)  Areolar tissue with an abundance of fat cells  Functions:  Insulates the body  Protects some organs  Serves as a site of fuel storage

© 2015 Pearson Education, Inc.

Blood (vascular tissue)  Softest of all the connective tissues  Blood cells surrounded by fluid matrix known as blood plasma  Functions as the transport vehicle for the cardiovascular system, carrying:  Nutrients  Wastes  Respiratory gases

© 2015 Pearson Education, Inc.

3. Muscle Tissue  Function is to contract, or shorten, to produce movement  Three types: 1.Skeletal muscle 2.Cardiac muscle 3.Smooth muscle

© 2015 Pearson Education, Inc. Muscle Tissue Types Skeletal muscle  Voluntarily (consciously) controlled  Attached to the skeleton and pull on bones or skin  Produces gross body movements or facial expressions  Characteristics of skeletal muscle cells  Long, cylindrical shaped and have striations (stripes)  Multinucleate (more than one nucleus)

© 2015 Pearson Education, Inc. Figure 3.20a Type of muscle tissue and their common locations in the body. (a) Diagram: Skeletal muscle

© 2015 Pearson Education, Inc. Muscle Tissue Types Cardiac muscle  Involuntarily controlled  Found only in the heart  Pumps blood through blood vessels  Characteristics of cardiac muscle cells  Short, branching cells that have striations  Uninucleate- cells have one nucleus

© 2015 Pearson Education, Inc. Figure 3.20b Type of muscle tissue and their common locations in the body. (b) Diagram: Cardiac muscle

© 2015 Pearson Education, Inc. Muscle Tissue Types Smooth muscle  Involuntarily controlled  Found in walls of hollow organs such as stomach, uterus, and blood vessels  Characteristics of smooth muscle cells  Spindle-shaped cells with no visible striations  Uninucleate

© 2015 Pearson Education, Inc. Figure 3.20c Type of muscle tissue and their common locations in the body. (c) Diagram: Smooth muscle

© 2015 Pearson Education, Inc. 4. Nervous Tissue  Composed of neurons and nerve support cells  Function is to receive and conduct electrochemical impulses to and from body parts

© 2015 Pearson Education, Inc. Figure 3.21 Nervous tissue. Brain Spinal cord Nuclei of supporting cells Neuron processes Cell body of neuron Diagram: Nervous tissue

© 2015 Pearson Education, Inc. Tissue Repair (Wound Healing) Tissue repair (wound healing) occurs in two ways: 1.Regeneration  Replacement of destroyed tissue by the same kind of cells 2.Fibrosis  Repair by dense (fibrous) connective tissue (scar tissue)

© 2015 Pearson Education, Inc.  Whether regeneration or fibrosis occurs depends on: 1.Type of tissue damaged 2.Severity of the injury  Clean cuts (incisions) heal more successfully than ragged tears of the tissue  If scar tissue replaces the previous tissue, it can negatively affect the function of the area, such as when scar tissue replaces cardiac tissue after a heart attack

© 2015 Pearson Education, Inc. Steps in Tissue Repair 1. Inflammation  Capillaries become very permeable, bringing fluid and immune cells to the area  Clotting proteins wall off the injured area to prevent other tissues from being exposed; clotting area exposed to the air hardens and dries into a scab

© 2015 Pearson Education, Inc. 2. Granulation tissue forms  Delicate replacement tissue with new capillaries forms  The immune system cleans the area and fibroblasts rebuild the tissue

© 2015 Pearson Education, Inc. 3. Regeneration of surface epithelium  Tissue regrows and scab detaches  Whether scar is visible or invisible depends on severity of wound