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.