The Tissue Level of Organization

What are the body tissues? Epithelial tissue Epithelial tissue Connective tissue Connective tissue Nervous tissue Nervous tissue Muscle tissue Muscle tissue Histology The study of tissues

Tissue Overview Epithelial Cover exposed surfaces Cover exposed surfaces Forms inner lining of body cavities Forms inner lining of body cavities Lines hollow organs Lines hollow organs Produces glandular secretions Produces glandular secretions Lacks blood vessels Lacks blood vessels Cells tightly packed and continuously replaced. Cells tightly packed and continuously replaced. Major Functions: protection, secretion, absorption and excretion. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Connective Fill internal spaces and provides frameworks Extracellular matrix consisting of fibers and fluid Stores fat Produces blood cells Protects against infection Helps repair damaged tissues. Major Functions: connects, supports, protects

Muscle Tissue Contracts to produce movements Neural (Nervous Tissue) Conducts electrical impulses Carries information Coordinates function

Key Note Tissues are collections of cells and extracellular material that perform a specific but limited range of functions.The four tissue types, in varying combinations, form all of the structures of the human body. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

An Orientation to the Tissues of the Body An Orientation to the Tissues of the Body Figure 4-1

What are the different types of epithelial tissue? 1. Simple epithelium (one layer of cells) A. Simple squamous epithelium – Thin, flattened Exchange of gases. Location: lungs, blood vessel lining, lymph vessels, thoracic and abdominal membranes. Exchange of gases. Location: lungs, blood vessel lining, lymph vessels, thoracic and abdominal membranes. B. Simple cuboidal epithelium – cube-shaped Secretion and absorption. Location: kidneys and various glands. Secretion and absorption. Location: kidneys and various glands.

What are the different types of epithelial tissue? C. Simple columnar epithelium – elongated cells with nuclei near basement membrane. Protection, secretion, absorption, secretion of mucus, possess microvilli. Location: uterus lining and digestive tract. Protection, secretion, absorption, secretion of mucus, possess microvilli. Location: uterus lining and digestive tract. D. Pseudostratified columnar epithelium – false stratification. Nuclei are at two or more levels. Moves mucus over surface of tissue. Location: Respiratory system. Moves mucus over surface of tissue. Location: Respiratory system.

What are the different types of epithelial tissue? 2. Stratified epithelium (two or more cell layers) A. Stratified squamous epithelium – made of different types of cells found in mouth and esophagus a) Stratified cuboidal epithelium – found in glands b) Stratified columnar epithelium – found in glands c) transitional epithelium – modified stratified squamous epithelium found in the urinary bladder, the ureters and urethra

Epithelial Tissue Drawings

What are the Functions of Connective Tissues? Structural framework Structural framework Fluid and solute transport Fluid and solute transport Physical protection Physical protection Tissue interconnection Tissue interconnection Fat storage Fat storage Microorganism defense Microorganism defense Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

What are the different types of connective tissue? 1. Connective Tissue (Proper) A.Areolar – forms delicate, thin membranes throughout the body. Location: Binds the skin to the underlying organs. Fills spaces between muscles. B.Adipose – also known as fat. Stores fat, cushions and insulates. Location: beneath the skin, in some abdominal membranes, around kidneys, heart and various joints. C. Reticular – Thin, branched collagenous fibers. Supports walls of the liver, spleen and lymphatic organs.

2.Dense Connective Tissue A. Regular – Strong, collagenous fibers. Bind structures as parts of tendons and ligaments. B. Irregular – Thicker, randomly distributed collagenous fibers. Location: Dermis C. Elastic – Made of elastic fibers and is flexible. Location: Lungs and blood vessels. Loose connective tissue – soft and few fibers Areolar tissue – soft, flexible tissue that protects the body organs

3. Specialized A. Bone (osseous tissue) – made of calcium and collagen that form circles around central canals Rapidly healing. Location: Bone Rapidly healing. Location: Bone B. Cartilage – very soft and flexible Dense connective tissue– very strong fibers that lack blood supply. Slow to heal. Dense connective tissue– very strong fibers that lack blood supply. Slow to heal. Provides supportive framework. Location: ends of various bones, ear, larynx, between vertebrae, knee, and pelvic girdle. Provides supportive framework. Location: ends of various bones, ear, larynx, between vertebrae, knee, and pelvic girdle. C. Blood – made of cells suspended in fluid. Formed in the hollow parts of certain bones.

Types of muscle tissue 1. Skeletal muscle – Long, threadlike cells containing several nuclei. Have striations (alternating dark and light cross-markings). controlled voluntarily by pulling on bones or skin controlled voluntarily by pulling on bones or skin Contract when stimulated by nerve impulses and relax when impulse is gone. Contract when stimulated by nerve impulses and relax when impulse is gone. 2. Cardiac muscle (heart muscle) – Striated with single nuclei. controlled involuntarily controlled involuntarily 3. Smooth muscle (visceral muscle) – Spindle-shaped cells with single nuclei. Involuntarily controlled. found in the walls of hollow organs such as stomach, bladder, uterus, and blood vessels found in the walls of hollow organs such as stomach, bladder, uterus, and blood vessels

What are the Four Types of Membranes? Mucous Lines cavities and tubes opening to the outside of the body. Lines cavities and tubes opening to the outside of the body. Made of epithelium and loose connective tissue. Made of epithelium and loose connective tissue. Secrete mucous Secrete mucous Mucous moistens surface Mucous moistens surface Examples: oral cavity, airways Examples: oral cavity, airways Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Serous Line internal body cavities that do not open to the outside Line internal body cavities that do not open to the outside Made of epithelial and loose connective tissue Made of epithelial and loose connective tissue Cells secrete watery fluid that lubricates surfaces. Cells secrete watery fluid that lubricates surfaces.Cutaneous Covers body surface Covers body surface Example: the skin Example: the skinSynovial Lubricates and lines joints Lubricates and lines joints Examples: knee, elbow Examples: knee, elbow