Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Fundamentals of Anatomy & Physiology Frederic H. Martini Lecture 4: Chapter 4 The Tissue Level of Organization Pages: Lecturer: Dr. Barjis Room: P313 Phone: (718)

Learning Objectives Identify the four major tissue types and describe their functions. Describe the relationship between form and function for each tissue type. Discuss the types and functions of epithelial tissues. Compare the structure and function of connective tissues.

Learning Objectives Explain the structure and function of the four types of membrane. Describe the three types of muscle tissue and the structural features of each. Discuss the basic structure and role of neural tissue.

Tissues are: Collections of specialized cells and cell products organized to perform a limited number of functions Histology = study of tissues The four tissue types are: Epithelial Connective Muscular Nervous Tissues of the Body: An Introduction Tissues and tissue types

Includes glands and epithelium Glands are secretory Is avascular Forms a protective barrier that regulates permeability Cells may show polarity Tissues and tissue types Epithelial tissue

Physical protection Control permeability Provide sensation Produce specialized secretions Functions of epithelium

Perform secretory functions Perform transport functions Maintain physical integrity Ciliated epithelia move materials across their surface Specializations of epithelium

The Polarity of Epithelial Cells

Cells attach via cell adhesion molecules (CAM) Cells attach at specialized cell junctions Tight junctions Desmosomes Gap junctions Maintaining the integrity of epithelium

Intercellular connections Animation: check tutorials

Basal lamina attaches to underlying surface Lamina lucida Lamina densa Germinative cells replace short-lived epithelial cells Structure of typical epithelium

Number of cell layers Simple Stratified Shape of apical surface cells Squamous Cuboidal Columnar Classification of epithelia

Squamous Epithelia

Cuboidal Epithelia

Transitional Epithelium

Columnar Epithelia

Exocrine glands Secrete through ducts onto the surface of the gland Endocrine glands Release hormones into surrounding fluid Glandular epithelia

Merocrine (product released through exocytosis) Apocrine (involves the loss of both product and cytoplasm) Holocrine (destroys the cell) Glandular secretions can be:

Mechanisms of Glandular Secretion Animation: Mechanisms of glandular secretion (check tutorial)

Unicellular Individual secretory cells Multicellular Organs containing glandular epithelium Classified according to structure Glands

A Structural Classification of Exocrine Glands

Establishing a structural framework Transporting fluids and dissolved materials Protecting delicate organs Supporting, surrounding and interconnecting tissues Storing energy reserves Defending the body from microorganisms Connective Tissues Connective tissue functions:

A Classification of Connective Tissues

Specialized cells Matrix Composed of extracellular protein fibers and a ground substance Connective tissues contain

Contains varied cell populations Contains various fiber types A syrupy ground substance Connective tissue proper

Fluid connective tissue Contains a distinctive cell population Watery ground substance with dissolved proteins Two types Blood Lymph

Less diverse cell population Dense ground substance Closely packed fibers Two types Cartilage Bone Supporting connective tissues

Contains fibers, a viscous ground substance, and a varied cell population Fibroblasts Macrophage Adipocytes Mesenchymal cells Melanocytes Mast cells Lymphocytes Microphages Connective tissue proper

Three types of fiber Collagen fibers Reticular fibers Elastic fibers Connective tissue proper

Classified as loose or dense Loose Embryonic mesenchyme, mucous connective tissues Areolar tissue Adipose tissue Reticular tissue Dense Dense regular CT Dense irregular CT Connective tissue proper

The Cells and Fibers of Connective Tissue Proper

Connective Tissue in Embryos

Adipose and Reticular Tissues

Dense Connective Tissues

Distinctive collections of cells in a fluid matrix Blood Formed elements and plasma Red blood cells, white blood cells and platelets Arteries carry blood away, veins carry to the heart Capillaries allow diffusion into the interstitial fluid Lymph Interstitial fluid entering the lymphatic vessels Fluid connective tissues

Formed Elements of the Blood

Cartilage and bone support the rest of the body Cartilage Grows via interstitial and appositional growth Matrix is a firm gel containing chondroitin sulfate Cells called chondrocytes Cells found in lacunae Perichondrium separates cartilage from surrounding tissues Three types: hyaline, elastic and fibrocartilage Supporting connective tissues

The Perichondrium and Types of Cartilage

Has osteocytes Depend on diffusion through canaliculi for nutrients Little ground substance Dense mineralized matrix Surrounded by periosteum Bone, or osseus tissue

Bone

Form a barrier Composed of epithelium and connective tissue Four types Cutaneous Synovial Serous Mucous Membranes Membranes are simple organs

Membranes

Line cavities that communicate with the exterior Contain lamina propria Mucous membranes

Line sealed internal cavities Form transudate Serous membranes

Cutaneous membrane Covers the body surface Synovial membrane Incomplete lining within joint cavities Membranes continue

Network of connective tissue proper consisting of Superficial fascia Deep fascia Subserous fascia The Connective Tissue Framework of the Body Organs and systems are interconnected

The Fasciae

Specialized for contraction Three types Skeletal Cardiac Smooth Muscle tissue

Muscle Tissue

Cells are multinucleate Striated voluntary muscle Divides via satellite cells Skeletal muscle

Cardiocytes occur only in the heart Striated involuntary muscle Relies on pacemaker cells for regular contraction Cardiac muscle

Non-striated involuntary muscle Can divide and regenerate Smooth muscle tissue

Conducts electrical impulses Conveys information from one area to another Neural tissue

Neurons Transmit information Neuroglia Support neural tissue Help supply nutrients to neurons Neural tissue cells

Neural Tissue

Cell body Dendrites Axon (nerve fiber) Carries information to other neurons Neural anatomy

Injured tissues respond in coordinated fashion Homeostasis restored by inflammation and regeneration Tissue Injuries and Aging Inflammation and regeneration

Isolates injured area Damaged cells, tissue components and dangerous microorganisms removed Infection avoided Regeneration restores normal function Tissue Injuries and Aging Inflammatory response

An Introduction to Inflammation

Change with age Repair and maintenance less efficient Structure altered Chemical composition altered Aging and tissue repair

Aging and cancer incidence Incidence of cancer increases with age 70-80% of all cases due to exposure to chemicals or environmental factors

Changes in a Tissue under Stress

You should now be familiar with: The four major tissue types and their functions. The relationship between form and function for each tissue type. The types and functions of epithelial tissues. The structure and function of connective tissues. The structure and function of the four types of membrane. The three types of muscle tissue and the structural features of each. The basic structure and role of neural tissue.