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Cells and Tissues Cells - building blocks of all life
Tissues - groups of cells w/ similar structure and function
Body Tissues – groups of cells with similar structure and function
Four primary types
Epithelial tissue (epithelium)
Connective tissue
Muscle tissue
Nervous tissue
Epithelial Tissues
Locations
Body coverings
Body linings
Glandular tissue
Functions
Protection
Absorption
Filtration
Secretion
Epithelium Characteristics
Often form sheets (like skin)
apical surface = free surface (top side)
lower surface bound to basement membrane
Avascular (no blood supply), but regenerate easily
Apical Surfaces
Classification of Epithelia
Shape of cells
Squamous – flattened
Cuboidal - cube-shaped
Columnar - column-like
Figure 3.17b
Glandular Epithelium
Endocrine gland – secrete hormones directly to blood
Exocrine gland – secrete into ducts, sweat glands for ex.
Connective Tissue Characteristics
Blood supply varies (a little to a lot)
Extracellular matrix: non-living material surrounding cells (2 components)
Ground substance: water, proteins, sugars
Fibers: protein fibers secreted by cells
Connective Tissue: BONE – protection and support
Hard matrix of calcium salts
Large numbers of collagen fiber
Connective Tissues: Hyaline Cartilage – protects joints, supports trachea
Most common type of cartilage
Composed of
Abundant collagen fibers
Rubbery matrix
Connective Tissue Types
Elastic cartilage – elastic ear support
Fibrocartilage – compressible discs between vertebrae
Connective tissues: dense connective tissue
Tendons - skeletal muscle to bone
Ligaments— attach bone to bone at joints
Dermis— lower layers of the skin
Connective Tissue Types: Loose Connective Tissues are soft and pliable
Areolar tissue
Most widely distributed connective tissue
Functions as a packing tissue
Can soak up excess fluid (causes edema)
Adipose tissue
Areolar tissue with fat cells
Insulates, protects, stores fuel
Connective Tissue Types: reticular tissue (also a loose connective tissue)
Delicate network of interwoven fibers
Creates space in lymph nodes, spleen, bone marrow
Connective Tissue Types: Blood
Blood cells surrounded by fluid matrix (blood plasma)
Transports nutrients/waste/hormones
Body MembranesComposed of epithelial and connective tissues.
Cover body surfaces
Line body cavities
Protect organs
4 types-
Mucous membranes – ‘wet’ membranes that open to exterior; Respiratory, urinary, digestive, etc.
Serous membranes – line body cavities, completely separate from exterior
4 types-
Cutaneous membranes – the skin, exposed directly to air
Synovial membranes -- lines capsules around joints, secretes lubricating fluid
Muscle Tissue – 3 types for movement
Skeletal muscle – voluntary control, multi-nucleate fibers, striated
Cardiac muscle – heart, intercalated discs, single branched cells
Smooth muscle – involuntary control (hollow organs & blood vessels)
Nervous Tissue – neurons and support cells
Sends impulses around the body
Irritability – detect environmental changes
Conductivity – send electrical signals