A&P Chapter 4

Groups of cells that similar in structure and performam a common or related function are called tissues.

• Epithelial
• Connective
• Muscle
• Nervous

covering

support

movement

control

The study of tissue.

a sheet of cells that covers a body surface or lines a body cavity

• covering and lining epithelium
• glandular epithelium

an upper free surface exposed to the body exterior or the cavity of an internal

lower attached

cell regions near the apical surface fiffer from those near the basal surface both in structure and function.

fingerlike extenstions of the plasma membrane that increase the exposed surface area

tiny hairlike projections that propel substances along their free surface

• adjacent to the basal surface of an epithelium
• thin supporting sheet
• acts as a selective filter that determines which molecules diffusing from the underlying connective tissue are allowed to enter the epithelium

A layer of extracellular material containing a fine network of collagen protein fibers that "belong to" the underlying connective tissue.

reinforces the epithelial sheet, helping it to resist stretching and tearing forces, and defines the epithelial boundry

supplied by nerves fibers

contains no blood vessels

• 1. innervated-supplied by blood vessels
• 2. avascular-contains no blood vessels

The are nourished by substances diffusing from blood vessels in the underlying connective tissue

• Protection
• Absorption
• Filtration
• Excretion
• Secretion
• Sensory reception

• consist of a single cell layer
• typically found where absorption, secretion, and filtration occur and a thin epithelial barrier is desirable

• composed of two or more cell layers stacked one on top of the other
• common in high abrasion areas where protection is important

• squamous
• cuboidal
• columnar

• flattened and scalelike
• nucleus is a flattened disc
• Can be stacked
• Can be simple or stratified

• boxlike, approximately as tall as they are wide
• nucleus is spherical
• Can be simple or stratified
• has microvilli

• tall and column shaped
• nucleus is elongated from top to bottom
• Do NOT layer
• has microvilli

• cells are flattened laterally, and they cytoplasm is sparse
• in a surface fiew, the close fitting cells resemble a tiled floor

• inner covering
• provides a slick, friction reducing lining in lymphatic vessels and in hollow organs of the cardiovascular system

• middle covering
• epithelium found in serous membranes lining of the ventral body cavity and covering its organs

• Single layer of cells that are as tall as they are wide
• important function are secretion and absorption

• single layer of tall, closely packed cells, aligned like soldiers ina row.
• lines digestive tract from the stomach through the rectum
• mostly associated with absorption and secretion

• Vary in height
• all if its cells rest on the basement membrane, but only the tallest reache the free surface of the epithelium
• cell nuclei lie at different levels above the basement membrane
• secrets or absorbs substances

• Polarity
• Attachment
• Avascularity
• Regeneration

• unique ability to stretch
• stratified
• Found in bladder

• collection of epitheliam cells that produce secretions
• tissue that forms glands
• classified by where product goes

glandular epithelium which secrets its product on to a surface

Ex: mucus, digesitve, enzymes, and milk

release their secretions into the fluids and blood

• exocytosis
• apocrine
• holocrine

merocrine glands produce and package the product in the cytoplasm and then transport it to the cell membrane where it is then expelled.

Ex: Sweat glands are a type of merocrine

• packs the apical portion of the cell with vesicle containing the secretory product. All get shed
• a piece of the cell is lost with its products are lost
• Ex: Milk production

• the whole cell is destroyed when the product is released.
• Ex: hair

Regulate and coordinate the activities other tissues, organs and organ systems

• mucous cells-epithelial linings of the intestinal adn respiratory tracts
• goblet-cuplike accumulation of mucin distends the top of the cell making the cells looke like a glass with a stem

• have 2 basic parts:
• an epithelium derived duct
• secretory unit (acinus) consisting of secretory cells

Most abundant in the body

• Connective tissue proper
• Cartilage
• Bone tissue
• Blood

• Binding & support
• Protection
• Insulation
• Transportation

• Common origin-all connective tissues arise from mesenchyme (embryonic tissue)
• Degrees of fascularity-connective tissue run the enitre gamut of vascularity
• Extracellular Matrix-non-living

• ground substance
• fibers
• cells

extracellular matrix

• Unstructured material that fills the space between the cells and contains the fibers.
• Holds large amounts of fluid and functions as a molecular sieve through which nutrients and toher dissolved substances and ciffuse between the capillaries and cells

• Collagen-
• Elastic
• Reticular fibers

• Strongest and most abundant
• Constructed primarily of the fibrous protein collagen

• Long, thin fibers that form branching networks in the extracellular matrix.
• Contain a rubber-like protein, elastin, which allows them to stretch and recoil like rubberbands
• Found where greater elasticity is needed

• Short, fine collagenius fibers with a slightly different chemistry and form.
• Continuous with collagen fibers, and they branch extensively forming delicate networks

• 1. Connective tissue proper-fibroblast
• 2. Cartilage-chondroblast
• 3. Bone-osteoblast
• 4. Blood-hematopoietic stem cell

• typically cluster along blood vessels
• Act as sensitive sentinels to detect foreign microorganisms (bacteria, fungi) and initiate local inflammatory responses against them

• macro=large
• phago=eat
• large irrecularly shaped cells the avidly phagocytize a bread variety of foreign material

• common embryonic tissue
• derived from embryonic mesoderm (middle embryonic cell layer)

• 2 sub classes:
• loose connective tissue (areolar, adipose, reticular)
• dense connective (dense regular, dense irregular, and elastic)

• classified as loose connective tissue
• supporting and binding other tissues
• holding body fluids
• defending against infection
• storing nutrients as fat
• contains fibroblasts
• Most abundant in the body

• similar to adipose in structure and function
• cells packed closely together (like chicken wire)
• richly vascularized

• resembles areolar connective tissue, but the only fibers in its matrix are retucular fibers
• largely in lymph nodes, spleen, and bone marrow

• Gel-like matrix with all 3 fiber types
• contains fibroblasts, macrophages, mast cells, and some white blood cell
• Wraps and cushions organs
• Plays important role in inflammation
• Holds and conveys tissue fluid
• Widely distributed under epithelia of body...forms lamina propria of mucous membrane
• Packages organs
• surround capillaries

• Primarily irregularly arranged collagen fiber
• Major cell type is fibroblast
• Able to withstand tension exerted in many directions and provides structural stength
• dermis of skin
• submucosa of digestive tract

• dense regular connective tissue containing a high proportion of elsatic fibers
• Allows for recoil of tissue following stretching
• Maintains pulsatile blow of blood through arteries
• Walls of large arteries

• Stands up to both tension and compression
• Qualities are between dense connective tissue and bone
• Lacks nerve fibers and is avascular
• Chondroblasts are its main cell type

• Hyaline Cartilage
• Elastic Cartilage
• Fibrocartilage

• Most abundant cartilage
• Provides firm support with some pliability
• Covers the head of long bones, tip of nose and sternum

• Found strength and stretchability are needed
• ear

• perfect strucutral intermediate between hyaline cartilage and dense regular connective tissue
• found where strong strong support an dability to withstand heavy pressure is required
• ex: intervertebral discs

• ability to support and protect the body structures
• Bone matrix is similar in structure than cartilage but is harder and more rigid because it has and added matrix element

• fluid within blood vessels is he most atypical connective tissue
• developes from mesenchyme and consists of blood cells
• functions as the transport vehicle for the cardiovascular system

main component of the nervous system

• highly specialized nerve cells that generate and conduct nerve impulses.
• branching cells with cytoplasmic extenstion
• respond to stimuli
• transmit electrical impulses over substantial distances

• highly cellular, well vascularized tissues that are responsible for most types of body movement
• possess myofilaments
• 3 types are:
• Skeletal, cardiac and smooth

• tissue is packaged by connective tissue sheets into rogans called skeletal muscle that ate attached to the bones of the skeleton
• Long, cylindrical cells that contain many nuclei.
• Striated
• Voluntary

• found only in the walls of the heart
• striated
• cells are uninucleate
• has intercalated discs

• its cells hsve no visible striations
• spindle shaped and contain one centrally located nucleus
• found mainly in the walls of hollow organs other than the heart

• cutaneous
• mucous
• serous

• Skin-organ system consisting of a keratinized stratified squamous epithelium firmly attached to a thick layer of dense irregular connective tissue
• Exposed to air and is a dry membrane

• lines body caivties that open to the exterior, such as those of the hollow organs of the digestive, respiratory, and urogenital tracts
• contain either stratified squamous or simple columnar

• found in closed ventral cavities
• simple squamous

• 1. Inflammation
• 2. Organization
• 3. Regeneration