A & P Unit 4: Tissues Skin and Body Membranes 2012 Pt. 1

What is a Tissue? Tissue - a group or mass of similar cells working together to perform certain common functions There are 4 major types of tissue Epithelial Connective Muscle Nervous

Epithelial Tissue General Characteristics: - Found throughout the body, covers all body surfaces both inside and out. - Main glandular tissue. - Attached to underlying connective tissue by noncellular nonliving basement membrane. - Usually has no vascular tissue - blood supply - Cells reproduce rapidly (rapid healing). - Cells tightly packed together Functions: Protection, secretion, absorption, excretion, sensory perception

6 Types of Epithelial Tissues Six Specific types of epithelial tissue - categorized based on the shape of the cells and the layers of cells. ( * We won't distinguish glandular epithelium because it is of the cuboidal or columnar type.) A. SIMPLE SQUAMOUS - single layer (simple) of very thin, flattened cells (squamous). Function: diffusion and filtration. Found in air sacs of lungs, walls of capillaries.

Epithelial Tissue B. SIMPLE CUBOIDAL - single layer, cube- shaped cells. Function: Secretion and absorption. Found: Lining of kidney tubules, ducts of glands, covering surface of ovaries

Epithelial Tissue C. SIMPLE COLUMNAR - single layer, elongated cells with their nuclei in about the same position in each cell (usually near the basement membrane). Protection, secretion, absorption. Found in the lining of digestive tract and uterus - contains scatter goblet cells functioning in the secretion of mucus - some columnar cells (involved in absorption) have tiny finger-like processes from their free surface called microvilli (increases surface area)

Epithelial Tissue D. STRATIFIED SQUAMOUS - multi-layered, squamous cells. Thicker tissue. Functions in protection. Found lining body cavities like the mouth and outer layer of skin

Epithelial Tissue Stratified squamous epithelium is further classified by the presence or absence of keratin, a tough protective protein, at the apical surface.keratinapical [edit] Nonkeratinizededit Non-keratinised surfaces must be kept moist by bodily secretions to prevent them drying out and dying. Types of non-keratinised stratified squamous epithelium include cornea (see also corneal epithelium), oral cavity, oesophagus, anal canal, vagina, and the internal portion of the lips [citation needed]corneacorneal epitheliumoral cavityoesophagusanal canalvaginalipscitation needed [edit] Keratinizededit Keratinised surfaces are protected from abrasion by keratin and kept hydrated and protected from dehydration by glycolipids produced in the stratum granulosum. Types of keratinized stratified squamous epithelium include skin, tongue (filiform papillae), and the external portion of the lipsskintonguefiliform papillaelips

Epithelial Tissue F. TRANSITIONAL EPITHELIUM - thick, layered cuboidal cells. "Stretchable" tissue, also forms barrier to block diffusion. Found: lining of urinary bladder.

Pseudostratified False and loosely packed cells that looking like multiple layers. These epithelia cells line the respiratory tract known as the trachae and the vas deferens of the male reproductive system.

Stratified Cuboidal and Columnar Sweat glands, mammary and salivary glands Basement membrane These types can be found in the larger ducts of various glands, including the pancreas, salivary, and sweat glands. If you are viewing an epithelium and it consists of more than 3-4 layers of cells, it will not be one of these types. Stratified squamous types and transitional are the only epithelia consisting of multiple cell layers.

Stratified Columnar

Comparing: Research the Structure associated with the Endocrine and Exocrine Glands and complete the table below: Endocrine GlandsExocrine Glands Structures Products Secretions

Connective Tissue General Characteristics: -Most abundant tissue in your body, found throughout -Binds structures together -Provides support, protection, framework, fills space, stores fat, produces blood cells, fights infection, and helps repair tissue. -Composed of more scattered cells with abundant intercellular material ' matrix -Made up of a ground substance (fluid, semi-solid) and fibers -Most has a good blood supply -Cells can reproduce

Common Cell Types Three Common types of cells: 1. mast cells (prevents blood clots) 2. macrophages (phagocytic) and 3. fibroblasts (most abundant, produce fibers)

Main Types of Fibers collagenous fibers - thick, made of protein collagen, major structural protein in the body, appear in long parallel bundles. Strong, flexible, but not very elastic, also known as white fibers. (bones, ligaments, tendons) - elastic fibers - microfibrils in protein elastin, yellow fibers. Not as strong, but very elastic (respiratory and vocal cords)

Fiber Types

Categories of Connective Tissue A. LOOSE C.T. or AREOLAR TISSUE - binds skin to underlying organs and organs to organs, space between muscles, throughout body B. ADIPOSE TISSUE - aka FAT, beneath skin, around kidneys and eyeballs, abdominal membranes. Function: Protective cushion, insulation to preserve body heat, stores energy, cells are called adipocytes

What does Adipose Tissue Look Like?

Fibrous Connective Tissue FIBROUS C.T. - dense tissue, closely packed, thick collagenous fibers and fine network of elastic fibers. Few cells, poor blood supply, thus slow healing. Tendons - connect muscles to bones Ligaments - connect bones to bones

Ligaments connect bones to bones

Cartilage (Chondrocytes) D. HYALINE CARTILAGE - very fine white (collagenous) fibers. Most common cartilage. Covers ends of bones and joints, noise, respiratory passages. E. ELASTIC CARTILAGE - more flexible and elastic, external ear and larynx F. FIBROCARTILAGE - very tough, large numerous collagenous fibers. Intervertebral disks, menisci G. BONE TISSUE - Osseus tissue. Rigid due to mineral salts. Layers - lamellae, haversian canals, osteocytes H. BLOOD TISSUE - circulates throughout the body I. RETICULOENDOTHELIAL - found scattered throughout the body

Muscle Tissue A. Skeletal - skeletal muscles - voluntary (striated) B. Smooth - in hollow organs, stomach - involuntary C. Cardiac - wall of the heart

Muscle Tissue: Note the nuclei

Nerve Tissue Found in brain, spinal cord, nerves A. Neurons - transmit signals B. Neuroglia - protection, support