1. Tissues and Tissue Types BCH 443 Biochemistry of Specialized Tissues

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

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

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

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

The Polarity of Epithelial Cells

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

Intercellular Connections

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

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

Squamous Epithelia

Cuboidal Epithelia

Transitional Epithelium

Columnar Epithelia

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

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

Mechanisms of Glandular Secretion

“(kö-nek´tiv) a fibrous type of body tissue with varied functions. The connective tissue system supports and connects internal organs, forms bones and the walls of blood vessels, attaches muscles to bones, and replaces tissues of other types following injury. Connective tissue can develop in any part of the body, and the body uses this ability to help repair or replace damaged areas. Scar tissue is the most common form of this substitute”. Connective Tissue:

Connective tissue consists mainly of long fibers embedded in noncellular matter, the ground substance. The density of these fibers and the presence or absence of certain chemicals make some connective tissues soft and rubbery and others hard and rigid. Compared with most other kinds of tissue, connective tissue has few cells. The fibers contain a protein called collagen. Connective Tissue Con’t:

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

A Classification of Connective Tissues

Specialized cells Specialized cells Matrix Matrix Composed of extracellular protein fibers and a ground substance Composed of extracellular protein fibers and a ground substance Connective Tissues Contain

Contains varied cell populations Contains varied cell populations Contains various fiber types Contains various fiber types A syrupy ground substance A syrupy ground substance Connective Tissue Proper

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

Less diverse cell population Less diverse cell population Dense ground substance Dense ground substance Closely packed fibers Closely packed fibers Two types Two types Cartilage Cartilage Bone Bone Supporting Connective Tissues

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

Three types of fiber Three types of fiber Collagen fibers Collagen fibers Reticular fibers Reticular fibers Elastic fibers Elastic fibers Connective Tissue Proper

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

The Cells and Fibers of Connective Tissue Proper (Figure 4.09)

Connective Tissue in Embryos (Figure 4.10)

Adipose and Reticular Tissues (Figure 4.11)

Dense Connective Tissues (Figure 4.12 A)

Dense Connective Tissues (Figure 4.12 B)

Dense Connective Tissues (Figure 4.12 C)

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

Formed Elements of the Blood (Figure 4.13)

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

The Perichondrium and Types of Cartilage (Figure 4.15 A)

The Perichondrium and Types of Cartilage (Figure 4.15 B)

The Perichondrium and Types of Cartilage (Figure 4.15 C)

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

Bone (Figure 4.16)

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

Membranes

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

Line sealed internal cavities Line sealed internal cavities Form transudate Form transudate Serous Membranes

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

Network of connective tissue proper consisting of Network of connective tissue proper consisting of Superficial fascia Superficial fascia Deep fascia Deep fascia Subserous fascia Subserous fascia Organs and Systems are Interconnected

The Fasciae

Specialized for contraction Specialized for contraction Three types Three types Skeletal Skeletal Cardiac Cardiac Smooth Smooth Muscle Tissue

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

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

Non-striated involuntary muscle Non-striated involuntary muscle Can divide and regenerate Can divide and regenerate Smooth Muscle Tissue

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

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

Neural Tissue

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

Changes in a Tissue under Stress