Tissue differentiation Human Tissues Tissue differentiation

Tissue Types Muscle Epithelial Connective Nervous

Muscle Tissue 3 types of muscle tissue Cardiac –heart Skeletal – attached to bones Smooth – internal organs and blood vessels

Cardiac Muscle

Skeletal Muscle

Smooth Muscle

Epithelial Tissue 3 types of epithelial tissue Squamous Cuboidal Columnar Descriptive layers Simple – one layer Stratified – more than one layer

Epithelial Cell Shapes

Simple Squamous Epithelia

Simple Cuboidal Epithelia

Simple Columnar Epithelia

Stratified Squamous Epithelia

Pseudostratified ciliated columnar epithelia

Connective Tissue 6 Types Loose connective tissue Dense connective tissue Adipose Blood Cartilage Bone

Loose Connective Tissue

Areolar C.T.

Dense Connective Tissue

Fibrous C.T.

Adipose Tissue

Blood

Blood smear

Cartilage

Cartilage types Hyaline Elastic Fibrocartilage

Hyaline

Elastic

Fibrous

Bone

Nerve Tissue

Hemophilia

Tissue Repair Occurs in two different ways: 1. Regeneration – replacement of destroyed tissue by the same kind of cells. 2. Fibrosis – repair by dense (fibrous) connective tissue…forms scar tissue.

Tissue Repair What determines which type of repair occurs? 1. Type of tissue damaged 2. Severity of injury

Tissue Repair Repair Success? Clean cuts – more successful than ragged tears.

Imbalances - Keloids

3 Events in Tissue Repair 1. Capillaries become very permeable Introduce clotting proteins A clot walls off the injured area Holds the edges of the wound together Walls off injured area (preventing bacteria/infection) Where clot exposed to air – dries/forms scar

3 Events in Tissue Repair 2. Formation of granulation tissue Delicate pink tissue Growth of new capillaries – bleed frequently Contains phagocytes (cleanup) of blood clot Rebuild collagen fibers

3 Events in Tissue Repair 3. Regeneration of surface epithelium Scab detaches Scar remains visible depending on severity

Regeneration of Tissues Tissues that regenerate easily Epithelial tissue (skin and mucous membranes) Fibrous connective tissues and bone Tissues that regenerate poorly Skeletal muscle Tissues that are replaced largely with scar tissue Cardiac muscle Nervous tissue within the brain and spinal cord

Developmental Aspects of Tissue Epithelial tissue arises from all three primary germ layers Muscle and connective tissue arise from the mesoderm Nervous tissue arises from the ectoderm With old age, there is a decrease in mass and viability in most tissues