anatomy and physiology - histolgy

Four Classes of Connective Tissue

-connective tissue proper -cartilage -bone tissue -blood

Germ layers

-embryonic -ectoderm -mesoderm -endoderm

Epithelium Tissue

-forms membranes -cells of this tissue may absorb/secrete substances -forms endocrine and exocrine glands

Endocrine Glands

-have ducts -secrete hormones that travel through the lymph or blood to target organs

Connective Tissue

-supports and reinforces body organs -surrounds and cushions body organs -characterized by having large amounts of extracellular material -widely distributed; found in bones, cartilages, and fat deposits

Nervous Tissue

-uses electrochemical signals to carry out its functions -basis of the major controlling system of the body -forms the brain and spinal chord

Five special characteristics

1. polarity 2. specialized contacts 3. supported by connective tissue 4. avascular but inverted 5. regeneration

Six Major Functions of Epithelium

1. protection 2. absorption/filtration 3. excretion 4. secretion 5. sensory reception

Simple Squamous

Function -passage of diffusion and filtration Description -simple layer, flattened, disc-shaped Location -lungs, kidney, air sacs, lining of the heart Two other locations: Endothelium -small molecules pass through rapidly -lining of lymphatic vessels, blood vessels, and the heart Mesothelium -epithelium of serous membranes in the ventral body cavity

Steps in Tissue Repair

Inflammation: -Release of inflammatory chemicals -Dilation of blood vessels -Increase in vessel permeability -Clotting occurs Organization and restored blood supply: -The blood clot is replaced with granulation tissue -Epithelium begins to regenerate -Fibroblasts produce collagen fibers to bridge the gap -Debris is phagocytized Regeneration and fibrosis: -The scab detaches -Fibrous tissue matures; epithelium thickens and begins to resemble adjacent tissue -Results in a fully regenerated epithelium with underlying scar tissue

Psuedostratified ciliated columnar

Lines much of the respiratory track

Stratified squamous

Lines the inside of the mouth, protection

Stratified Cuboidal

Location -some sweat and mammary glans

Elastic

Networks of long, thin, elastin fibers that allow for stretch

Embryonic

Not yet developed

Reticular

Short, fine, highly branched collagenous fibers

Simple Vs. Stratified Vs. Pseudo stratified

Simple- one layer Stratified - two or more Pseudo - false layers

Cartilage

Three types of cartilage: -Hyaline cartilage: ends of joints and bones -Elastic cartilage: nose and ears -Fibrocartilage: knee, the pubic symphysis, and the vertebral discs

Connective Tissue Proper

Types: -Loose connective tissue •Areolar •Adipose •Reticular Dense connective tissue •Dense regular •Dense irregular •Elastic

Glandular Epithelia

one or more cells that makes and secretes an aqueous liquid

Stratified Columnar

small amounts in pharynx, male urethra, and lining in some glandular ducts

Major Functions of Connective Tissue

-Binding and support (bones/cartilage) -Protection -Insulation -Transportation (blood)

Epithelial Membranes

-Cutaneous membrane -Mucous membranes: Mucosae; Line body cavities open to the exterior (e.g., digestive and respiratory tracts) -Serous Membranes: Serosae—membranes (mesothelium + areolar tissue) in a closed ventral body cavity; Parietal serosae line internal body walls; Visceral serosae cover internal organs

Structural Elements of Connective Tissue

-Ground substance -Cells -Three types of fibers (collagen, elastic, reticular)

Cells

-Mitotically active and secretory cells = "blasts" -Mature cells = "cytes" -Fibroblasts in connective tissue proper -Chondroblasts and chondrocytes in cartilage -Osteoblasts and osteocytes in bone -Hematopoietic stem cells in bone marrow -Fat cells, white blood cells, mast cells, and macrophages

Exocrine Glands

-More numerous than endocrine glands -Secrete products into ducts -Secretions released onto body surfaces (skin) or into body cavities -Examples include mucous, sweat, oil, and salivary glands -The only important unicellular gland is the goblet cell

Collagen

-Strongest and most abundant type -Provides high tensile strength

Muscle Tissue

-allows for body movement of limbs and for organ movements within the body -allows you to smile, grasp, swim, ski, and throw a ball -its cells shorten to exert force

Endoderm

The innermost of the three primary germ layers of an animal embryo, developing into the gastrointestinal tract, the lungs, and associated structures

Mesoderm

The middle embryonic germ layer, lying between the ectoderm and the endoderm, from which connective tissue, muscle, bone, and the urogenital and circulatory systems develop

Ectoderm

The outermost of the primary germ layers of an animal embryo. In vertebrates, the ectoderm gives rise to the epidermis and associated tissues (such as hair and sweat glands), enamel of the teeth, sense organs, nervous system, and lining of the nose, mouth, and anus

Mesonchymal

The part of the embryonic mesoderm, consisting of loosely packed, unspecialized cells set in a gelatinous ground substance, from which connective tissue, bone, cartilage, and the circulatory and lymphatic systems develop.