Chapter 2 Book Notes Flashcards
Tissues
Group of cells that are similar in structure and function
Four primary tissue types
- epithelial (covering)
- connective (support)
- nervous (control)
-muscle (movement)
Epithelial/epithelium tissue
-Lining, covering, and glandular tissue of the body
-covers all free surface inside and out
-protects, absorption, filtration, and secretion
Epithelium characteristics
-except for glandular it fits close together to form continuous sheets bound by specialized cell junctions (desmosomes and tight junctions)
- have one free slick and smooth surface or edge
-anchored on a basement membrane
-no blood supply of their own and depend on diffusion from capillaries (avascular)
- regenerate easily
Classifications of simple epithelium
1.cell arrangements
Simple epithelium
- one layer
Stratified epithelium
- more than one layer
-named for the cells on the top layer as the ones on the bottom may seem squished and look like 1 layer
- Shape of cells
Squamous- flattened like fish scales
Cuboidal- cube shaped
Columnar- column shaped
Simple epithelium
Most concerned with absorption, secretion, and filtration. Since very thin protection is not a specialty
Apical surface
The free unattached surface of edge of epithelial tissue
Basement membrane
The anchored (basal) surface that the epithelium rests on
Simple squamous epithelium
-single layer of squamous cells resting on basement membrane
-forms membranes where filtration or exchange of substances by rapid diffusion occurs
-air sacs of the lungs, forms wall of capillaries, serous membranes
Serous membranes
Slicks membranes that line the ventral body cavity and cover the organs in their cavities
Simple cuboidal epithelium
-one layer of cuboidal cells resting on a basement membrane
-common in glands and their associated small tubes (ducts)
-sweat glands, pancreas, walls of kidney tubules, and covers surface of ovaries
Simple columnar epithelium
-single layer of tall cells that fit closely together
-lines entire digestive tract
Goblet cells
Produce a lubricating mucus, often seen in simple columnar
Mucus membrane (mucosae)
Epithelial membranes that line body cavities open to the body exterior
Pseudostratified columnar epithelium
-all cells rest on membrane but some cells are shorter than others making the nuclei appear on different levels
-gives false impression that it it stratified
-mainly functions in secretion and absorption
- ciliated variety lines respiratory tract and mucus from growler cells acts as a “sticky trap” to catch dust and debris
-Cilia propel mucus upward and away from lungs
Stratified epithelia
-consists of two or more cell layers
-more durable than simple
-functions primarily in protection
Stratified squamous
-most common epithelium
-the cells at the free edge are squamous but the ones near the basement membrane are cuboidal or columnar
-in sites that receive friction or abuse
-surface of the skin, mouth, and esophagus
Stratified cuboidal
-two cells layers with (at lest) the surface cells being cuboidal
-fairly rare in the body
-found in the ducts of the large glands
Stratified columnar
-surface cells are columnar
-basal cells vary in size and shape
-rare
-ducts of large glands
Basal
Bottom cells/surface
Transitional epithelium
-highly modified, stratified squamous epithelium
-cells of basal layer are cuboidal or columnar
-cells are free surface vary in size and shape
-when organ is stretched there are a few layers and surface layer cells are squamouslike
-unstretched there are many layers and superficial cells are dome shaped
-forms lining of bladder, ureters, and part of urethra
Connective tissue
-connects body parts
-found everywhere
-most abundant and widely distributed of tissue types
-protection, support, binding
Connective tissue characteristics
- variations in blood supply (most are vascularized)
-tendons and ligaments do not have good blood supply so they heal slowly
-extracellular matrix
-no loving substances found outside the cell
Types of connective tissues
-bone tissue (osseous)
-cartilage tissue
-hyaline cartilage
-fibrocartilage
-elastic cartilage
-dense CT
-tendons
-ligaments
-loose CT
-areolar CT
- adipose CT
-reticular CT
-blood (Vascular) tissue
Bone tissue
-composed of osteocytes in lacunae
-surrounded by very hard matrix that contains calcium, salt, and cartilage fibers
Connective Tissue (CT)
All connective tissue consists of living cells surrounded by a extracellular matrix. Their major differences reflect specific cell types, fiber types, and number of fibers in the matrix
Cartilage
-less hard and more flexible
-chondrocytes
1. hyaline cartilage
-most abundant cartilage
- forms trachea, attaches ribs to breastbone, and growth plates
2. fibrocartilage
-highly compressible
-cushion like discs between vertebrae
3. elastic cartilage
- found in structures with flexibility
-external ear
Dense connective/fibrous tissue
-collagen fibers are main matrix
-fibroblasts
-tendons & ligaments, lower layers of the skin
Tendons
Attach skeletal muscles to bone
Ligaments
Connect bone to bone
Loose connective tissue
-softer
-more cells and fewer fibers
- adipose, areolar, reticular
Areolar CT
-type of loose CT
-most widely distributed in the body
-soft, pliable, cobweb shaped
-protects and cushions body organs
-connective tissue “glue” because it helps hold internal organs together
-when looked at under a microscope most of the matrix appears to be an empty space
-when a body region is inflamed it soaks up the fluid
Adipose CT
-fat
-subcutaneous tissue beneath the skin
-insulates the body
-protects some organs
-kidneys, hips, breast, and belly
Reticular CT
-interwoven reticular fibers
-forms internal frame work of an organ
-lymph nodes, spleen, bone marrow
Blood
-considered a tissue because it consists of blood cells and a non living, fluid matrix called blood plasma
-“fibers” are proteins
-
Muscle tissue
-specialized to contract and shorten
-produces movement
-skeletal, cardiac, nervous
Skeletal muscle
-muscle connected to bone
-can be controlled voluntarily
-long cylindrical cells
-obvious striations
-muscle fibers
Cardiac muscle
-found only in the heart wall
-many striations but cells only have one nucleus and are relatively short
-cells fit tightly together at junctions (intercalated discs)
-ID contain gap junctions that allow ions to pass from cell to cell
-involuntary
Smooth muscle
-no visible striations
-walls of hollow organs
-stomach, uterus, and blood vessels
-contract and propel substances
-contracts more slowly than other types of MT
Nervous tissue
-neurons
-irritability and conductivity
-neuroglia insulate, support, and protect delicate neurons
-brain, spinal chord, nerves
