chapter 3 – part 2

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 to connective Avascular – no direct blood supply

Diffusion Regenerate easily

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 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…

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

Stratified Cuboidal & Stratified Columnar: Rare; large ducts

EPITHELIAL TISSUE, CONT’D…Stratified Epithelia, cont’d…

Transitional Epithelia: function is stretching

EPITHELIAL TISSUE, CONT’D…Stratified Epithelia, cont’d…

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, oil Liver

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 - choanocytesI - stratified columnar epithelium with cilia.

Functions: protection, support, & binding together

Most abundant tissue type Found everywhere in the body

CONNECTIVE TISSUE

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: Fat (soft); Bone (hard)

Tissue 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…

Cartilage – avascular Less 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 & becomes puffy

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 Connective Tissue Delicate 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

CONNECTIVE TISSUE, CONT’D…TYPES, CONT’D…

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

Skeletal Muscle- (striated muscle) Attached to skeleton; forms flesh Voluntary Cells are long, cylindrical, multinucleate, & striated

TYPES OF MUSCLE TISSUE (3 TYPES)MUSCLE TISSUE, CONT’D…

Cardiac Muscle- (heart only) Has striations, uninucleate; fit tightly together; gap junctions

Involuntary

MUSCLE TISSUE, CONT’D…TYPES, CONT’D…

Smooth Muscle- (visceral) No striations, single nucleus & spindle-shaped (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

MUSCLE TISSUE, CONT’D…TYPES, CONT’D…

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 prevent further injury.

- 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 scab3. Granulation tissue forms (new skin)4. Epithelium regenerates/scab falls

off (healed)**Scar Tissue cannot function as

original cells.

IV. NERVOUS TISSUE….CONT’D

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 after

birth

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 pregnancy

V. Development Aspects of Cells & Tissues…Cont’d

Atrophy: decrease in size – loss of stimulation Ex. Muscle reduction from wearing a cast

V. Development Aspects of Cells & Tissues…Cont’d