CHAPTER 3 PART 2 Body Tissues TISSUE Histology

CHAPTER 3 – PART 2 Body Tissues

TISSUE �Histology � 4 Tissue Types: � 1. Epithelial – (covering) � 2. Connective – (support) � 3. Muscle – (movement) � 4. Nervous – (control)

EPITHELIAL TISSUE �Lining, covering, & glandular �Functions: Protections, absorption, filtration, & secretion

EPITHELIAL TISSUE, CONT’D… �Special Characteristics: �Cells fit closely together to form sheets �Has a free surface (apical surface) �Lower surface – (basement membrane) �Epithelial �Avascular �Diffusion to connective – no direct blood supply

EPITHELIAL TISSUE, CONT’D… �Classification of epithelium �Named according to # of layers & shape of cells at the free surface �Layers: �Simple (1 layer) �Stratified (2 or more layers) �Shape: �Squamous – flat �Cuboidal – cube shaped �Columnar – taller than wide

EPITHELIAL TISSUE, CONT’D… �Simple Epithelium: absorption, secretion, & filtration �Simple Squamous Epithelium – forms serous membranes (serosae fluid) � Lines body cavities & organs

EPITHELIAL TISSUE, CONT’D…Simple Epithelium, cont’d… �Simple Cuboidal – glands & ducts

EPITHELIAL TISSUE, CONT’D…Simple Epithelium, cont’d… �Simple columnar epithelium – forms mucus membranes (mucosae). �Lines cavities open to exterior �Ex. Respiratory Tracts, Digestive Tracts

EPITHELIAL TISSUE, CONT’D…Simple Epithelium, cont’d… �Pseudostratified Columnar Epithelium �Lines Respiratory Tract �Ciliated

EPITHELIAL TISSUE, CONT’D… �Stratified Epithelia–layered; protects �Stratified Squamous Epithelium – most common; high abuse & friction. � Ex. Skin, mouth, esophagus

EPITHELIAL TISSUE, CONT’D…Stratified Epithelia, cont’d… �Stratified Cuboidal & Stratified Columnar: �Rare; large ducts

EPITHELIAL TISSUE, CONT’D…Stratified Epithelia, cont’d… �Transitional stretching Epithelia: function is

EPITHELIAL TISSUE, CONT’D… �Glandular Epithelia: glands; produces & secretes � 2 types: � 1. Endocrine Glands (ductless) � Directly into the blood stream � Hormones (ovaries, testes, adrenal) � 2. Exocrine Glands (ducts) � Sweat, � Liver oil

Answers: A - simple columnar epithelium. B - simple columnar epithelium with cilia. C - stratified squamous epithelium. D - simple squamous epithelium. E - transitional epithelium. F - pseudostratified epithelium. G - stratified squamous epithelium. H - choanocytes I - stratified columnar epithelium with cilia.

CONNECTIVE TISSUE �Functions: protection, support, & binding together �Most abundant tissue type �Found everywhere in the body

CONNECTIVE TISSUE, CONT’D… COMMON CHARACTERISTICS: � Some vascular � Some avascular (cartilage) – heals slowly � Many different types of cells � Extracellular Matrix: non-living substance outside of cell; can be liquid, semisolid or gel-like, or very hard �Examples: � Tissue Fat (soft); Bone (hard) can bear weight, withstand stretching & abrasions.

CONNECTIVE TISSUE, CONT’D… TYPES OF CONNECTIVE TISSUE: �Bone (osseous tissue) – vascular �Bone cells surrounded by hard matrix of calcium salts & collagen fibers �Function: protect & support other organs

CONNECTIVE TISSUE, CONT’D…TYPES, CONT’D… �Cartilage �Less – avascular hard/more flexible than bone �Hyaline cartilage- voice box; covers end of bone; attaches ribs to sternum; skeleton of fetus �Elastic cartilage- more elasticity. Ex: ears, nose �Fibrocartilage- highly compressible and cushion-like; between vertebrae

CONNECTIVE TISSUE, CONT’D…TYPES, CONT’D… �Dense Connective Tissue (fibrous tissue) �Mostly collagen fibers �Forms strong, rope-like structures �Ex: Tendons; Ligaments

CONNECTIVE TISSUE, CONT’D…TYPES, CONT’D… � Loose Connective Tissue- Softer & fewer fibers �Areolar Tissue �Soft, pliable tissue that protects & wraps body organs �Universal packing tissue & connective tissue glue that helps hold internal organs together �Edema- areolar tissue soaks up fluid in inflamed area; swells &

CONNECTIVE TISSUE, CONT’D…TYPES, CONT’D… LOOSE CONNECTIVE TISSUE, CONT’D �Adipose Tissue – “fat” �Forms subcutaneous layer below skin; insulates & protects from heat & cold.

CONNECTIVE TISSUE, CONT’D…TYPES, CONT’D… �Reticular �Delicate Connective Tissue network of fibers �Found in lymph nodes �Ex: Spleen and bone marrow.

CONNECTIVE TISSUE, CONT’D…TYPES, CONT’D… �Blood – “vascular tissue” �Blood cells surrounded by blood plasma �Protein fibers in blood �Blood clotting

MUSCLE TISSUE �Specialized to contract or shorten �Muscle Cells (muscle fibers)

MUSCLE TISSUE, CONT’D… TYPES OF MUSCLE TISSUE (3 TYPES) �Skeletal Muscle- (striated muscle) �Attached to skeleton; forms flesh �Voluntary �Cells are long, cylindrical, multinucleate, & striated

MUSCLE TISSUE, CONT’D…TYPES, CONT’D… �Cardiac �Has Muscle- (heart only) striations, uninucleate; fit tightly together; gap junctions �Involuntary

MUSCLE TISSUE, CONT’D…TYPES, CONT’D… �Smooth �No Muscle- (visceral) striations, single nucleus & spindleshaped (pointed at both ends) �Found in walls of stomach, bladder, uterus & blood vessels (hollow organs) �Contracts slowly �Peristalsis – wave-like motion through small intestine �Involuntary

IV. NERVOUS TISSUE �Cells = Neurons �Function = Irritability & Conductivity A. Tissue Repair (Wound Healing) - - Defense at tissue level – skin, mucous membranes, cilia, and acid in stomach glands. Inflammation – body response to

IV. NERVOUS TISSUE…. CONT’D - - Immune Response – specific to invaders 2 Ways tissue repairs (depends on tissue type and severity of injury) Regeneration: replacement of destroyed tissue by same kinds of cells - Fibrosis: repair by dense connective tissue (fibrous) – forms scar tissue -

IV. NERVOUS TISSUE…. CONT’D - Process of tissue repair: 1. Capillaries become permeable/allows clotting fibers to seep to injury (bleed) 2. Blood Clot forms/then scab 3. Granulation tissue forms (new skin) 4. Epithelium regenerates/scab falls off (healed) **Scar Tissue cannot function as

V. Development Aspects of Cells & Tissues �Growth through cell division puberty �Replacement of tissue exposed to friction lifetime �Epithelial Tissue – Mitotic �Connective Tissue – Mitotic (forms scar tissue) �Muscle Tissue – Amitotic after puberty �Nervous Tissue – Amitotic shortly

V. Development Aspects of Cells & Tissues…Cont’d � Aging – Caused by chemical and physical exposures and genetics, and stress � Neoplasm: abnormal Cell division – multiply wildly – benign or malignant (tumor) � Hyperplasia: enlarged tissue due to local irritant or condition �Ex. Anemia/Bone marrow undergoes hyperplasia to produce more red blood cells �Ex. Breast enlargement during

V. Development Aspects of Cells & Tissues…Cont’d �Atrophy: decrease in size – loss of stimulation �Ex. Muscle reduction from wearing a cast