Chapter 4 A&P

connective tissue

characteristics of this tissue type include: -Common origin: mesenchyme -Degrees of vascularity -Extracellular matrix: this tissue type are largely nonliving extracellular matrices, which separates the living cells of the tissue.

adipocytes

commonly called fat cells, account for 90% of adipose tissue mass. The matrix is scanty and the cells are packed closely together. A glistening oil droplet occupies most of a fat cell's volume and displaces the nucleus to one site. Mature cells are among the largest cells in the body. As they take up or release fat, they become plumper or more wrinkled.

stratified epithelia

composed of two or more layers stack on top of each other. They are common in high-abrasion areas where protection is important, such as the skin surface and the lining of the mouth. These cells are named according to the shape of the cells in the apical layer.

fibroblast

connective tissue proper class. Flat branching cells that appear spindle shaped in profile. Basic cells, secrete extracellular substance

-blast

immature or undifferentiated cells, this suffix meaning "bud" or "sprout" but also meaning forming. -Mitotically active and secretory cells

basement membrane

the two laminae (reticular and basal) form this term. It reinforces the epithelial sheet, helps it resist stretching and tearing, and defines the epithelial boundary.

hematopoietic stem cell

the undifferentiated blast cell that produces blood cells. It is not located in the blood and it does not make the fluid matrix (plasma) of that tissue.

Ground substance

the unstructured material that fills the space between the cells and contains the fibers. It is composed of interstitial tissue fluid, cell adhesion proteins, and proteoglycans. -It consists of large amounts of fluid and functions as a molecular sieve, or medium, through which nutrients and other dissolved substances can diffuse between the blood capillaries and the cells.

Endocrine glands

these are often called ductless glands. They produce hormones, messenger chemicals that they secrete by exocytosis directly into the extracellular space. They are structurally diverse. Most are compact multicellular organs, but some individual hormone-producing cells are scattered in the digestive tract lining in the brain. -These secretions are also varied.

Mesenchyme

All connective tissues arise from this embryonic tissue. It has a fluid ground substance containing fine sparse fibers and star-shaped cells. Some of these cells remain and provide a source of new cells in mature connective tissues.

loose connective tissue, areolar

Gel-like matrix with all three fiber types; cells: fibroblasts, macrophages, mast cells, and some WBC. It's function is to wrap and cushion organs, phagocytize bacteria, play a role in inflammation, and hold and convey tissue fluid. -location: widely distributed under epithelia of body, packages organs, and surrounds capillaries.

stratified columnar epithelium

Has a limited distribution in the body. Small amounts are found in the pharynx, the male uretha, and lining some glandular ducts. It also occurs at transition areas or junctions between two other types of epithelia. * only its apical layer of cells is columnar.

mucin

In humans, all such uncicellular glands produce this. It is a complex glycoprotein that dissolves in water when secreted. Once dissolved, it forms mucus, a slimy coating that protects and lubricates surfaces.

Cartilage

It is tough and flexible, providing a resilient rigidity to the structures it supports. It lacks nerve fibers and is avascular. It receives its nutrients by diffusion from blood vessels located in the connective tissue membrane surrounding it. -It is also up to 80% water.

areolar connective tissue

Most widely distributed connective tissue in the body. the functions of this tissue include: 1. Supporting and binding other tissues (the job of the fibers) 2. Holding body fluids (the ground substance's role) 3. Defending against infection (WBC and macrophages) 4. Storing nutrients as fat (fat cells) -most obvious structural feature of this tissue is the loose arrangement of its fibers. The matrix is a small open space. This tissue provides a reservoir of water and salts for surrounding body tissues.

smooth muscle

Named so because its cells have no visible striations. These cells are spindle shaped and contain one centrally located nucleus. it is mainly found in the walls of the hollow organs other than the heart. It squeezes substances through these organs by alternately contracting and relaxing. *involuntary muscle

Dense regular connective tissue

Often called fibrous connective tissues. contains closely packed bundles of collagen fibers running in the same direction, parallel to the direction of pull. This arrangement results in white, flexible structures with great resistance to tension where the tension is exerted in a single direction. -The collagen fibers are slightly wavy, which allows the tissue to stretch a little. -It forms tendons -also forms fascia

mesoderm

Primary germ layer that forms the skeleton and muscles of the body.

pseudostratified columnar epithelium

The cells of this tissue vary in height. All of its cells rest on the basement membrane, but only the tallest reach the free surface of the epithelium. Because the cell nuclei lie at different levels above the basement membrane, the tissue gives the false (pseudo) impression that several layers are present. The short cells are relatively unspecialized and give rise to the taller cells. -It secretes or absorbs substances, particularly mucous. -Location: trachea, most of the upper respiratory tract, male's sperm-carrying ducts and ducts of large glands.

elastic connective tissue

The dense regular connective tissue in a few ligaments, such as connecting adjacent tissue are very elastic. This is called? Many of the larger arteries have this.

organization

The first phase that occurs in tissue repair even if inflammation is going on. The blood clot is replaced by granulation tissue, a delicate pink tissue composed of several elemets. It contains capillaries that grow in from nearby areas and lay down a ew capillary bed.

epithelial functions

The main type of tissue that accomplishes many functions, 1. protection, 2. absorption, 3. filtration, 4. excretion, 5. secretion, and 6. sensory reception.

mast cells

These cells typically cluster along blood vessels. They detect foreign microorganisms and initiate local inflammatory responses against them. Contains chemicals that mediate inflammation (heparin, histamine, proteases)

stratified cuboidal epithelium

This tissue type is quite rare in the body, mostly found in the ducts of some of the larger glands. It typically has two layers of these cells.

epithelium

This type of tissue has an apical surface and a basal surface. The two surfaces differ in both structure and function. For this reason, we say this tissue has apical-basal polarity.

stroma

When reticular connective tissue is limited to certain sites, it forms a labyrinth-like ______, or internal framework, that can support many free blood cells in lymph nodes, the spleen, and bone marrow.

Collagen fibers

a connective tissue fiber. They are constructed primarily of the fibrous protein collagen. They are extremely tough and provide high tensile strength to the matrix.

elastic fibers

a connective tissue fiber. They are long, thin fibers that form branching networks in the extracellular matrix. They contain a rubber-like protein called elastin, that allows them to stretch and recoil like rubber bands. When stretched and released, these fibers snap the connective tissue back to its normal length and shape.

Reticular fibers

a connective tissue fiber. short, fine, collagenous fibers with a slightly different chemistry and form. They are continuous with collagen fibers, and they branch extensively forming delicate networks that surround the small blood vessels and support the soft tissue of organs. -They are abundant where connective tissue abuts other tissue types.

serous membranes

a covering and lining membrane, aka serosae. They are the moist membranes found in closed ventral body cavities. It consists of simple squamous epithelium resting on a thin layer of loose connective areolar tissue. -pleurae: lines the thoracic wall and covers the lungs -pericardium: encloses the heart -peritoneum: encloses the abdominopelvic viscera.

mucous membranes

a covering and lining membrane. Aka mucosae. It lines all body cavities that open to the outside of the body, such as the hollow organs of the digestive, respiratory, and urogenital tracts. -They are "wet" or moist, bathed by secretions.

cutaneous membranes

a covering and lining membrane. It is the skin, an organ system consisting of a keratinized stratified squamous epithelium (epidermis) firmly attached to a thick layer of connective tissue (dermis). It is exposed to air and is a dry membrane.

tight junctions

a series of integral protein molecules in the plasma membranes of adjacent cells fuse together, forming an impermeable junction that encircles the cell. They help prevent molecules from passing through the extracellular space between adjacent cells. -They also help keep proteins in the apical region of the plasma membrane from diffusing into the basal region, thus help to maintain epithelial polarity.

Epithelial tissue

a sheet of cells that covers a body surface or lines a body cavity. Two forms occur in the body: covering and lining and glandular. -It forms boundaries between different environments, and nearly all substances received or given off by the body must pass through this type of tissue.

endothelium

a simple squamous tissue, "inner covering", provides a slick, friction-reducing lining in lymphatic vessels and in all hollow organs of the cardiovascular system--blood vessels and the heart. Capillaries consist exclusively of this tissue.

mesothelium

a simple squamous tissue, "middle covering", the epithelium found in serous membranes, the membranes lining the ventral body cavity and covering its organs.

simple columnar epithelium

a single layer of tall, closely packed cells, aligned like soldiers in a row. It lines the digestive tract from the stomach through the rectum. These cells are mostly associated with absorption and secretion of mucous, enzymes, and other substances. -Some display cilia on their free surfaces, which help move substances or cells through an internal passageway. -Locations: nonciliated lines most of the digestive tract, gallbladder, and excretory ducts of some glands. Ciliated variety lines small bronchi, uterine tubes, and some regions of the uterus.

basal lamina

a thin supporting sheet that is adjacent to the basal surface of an epithelium. Noncellular, adhesive sheet consists largely of glycoproteins secreted by epithelial cells plus some fine collagen fibers. -It acts as a selective filter that determines which molecules diffusing from the underlying connective tissue are allowed to enter the epithelium. -It also acts as scaffolding along which epithelial cells can migrate to repair a wound.

Hyaline cartilage

aka gristle, the most abundant cartilage in the body. It contains large numbers of collagen fibers but they are not viewed by unaided eye. They provide firm support with some pliability. -covers the ends of long bones as articular cartilage, providing springy pads that absorb compression at joints. They also support the tip of the nose, connects the ribs to the sternum, and supports most of the respiratory system passages.

osseous tissue

also known as bone tissue. It has an exceptional ability to support and protect body structures. Bones of the skeleton also provide cavities for storing fat and synthesizing blood cells. Bone matrix is similar to that of cartilage but his harder and more rigid because of its inorganic calcium salts.

secretion

an active process. It cans refer to both the gland's product and the process of making and releasing a product.

osteoblast

bone class

cuboidal cells

boxlike, approximately as tall as they are wide. The nuclei is spherical.

intercalated discs

branching cells that fit together tightly at unique junctions in cardiac muscles.

chondroblast

cartilage class

simple cuboidal epithelium

consists of a single layer of cells as tall as they are wide. The spherical nuclei stain darkly, causing the cell layers to look like a string of beads. Important functions are secretion and absorption. -It also forms the walls of the smallest ducts of glands and of many kidney tubules.

simple epithelia

consists of a single layer. They are typically found where absorption, secretion, and filtration occur and a thin epithelial barrier is desirable. Protection is not one of their specialties.

glands

consists of one or more cells that make and secrete a particular product (or secretion). The product is an aqueous fluid that usually contains proteins, but there is variation. Some release a lipid or steroid rich secretion. -May be endocrine or exocrine (where they release their product) -May be unicellular or multicellular (relative cell number)

tendons

cords that attach muscles to bones; flat, sheet-like ____ are called aponeuroses that attach muscles to other muscles or to bones; and the ligaments that bind bones together at joints.

reticular lamina

deep to the basal lamina, it is a layer of extracellular material containing a fine network of collage protein fibers that "belongs to" the underlying connective tissue. The two laminae (this one and basal), form the basement membrane.

ectoderm

embryonic germ layer; forms the epidermis of the skin and its derivatives, and ervous tissues.

endoderm

embryonic germ layer; forms the lining of the digestive tube and its associated structures.

fibrosis

fibrous connective tissue that proliferates to form scar tissue.

fascia

fibrous membrane that wraps around muscles, groups of muscles, blood vessels, and nerves.

microvilli

fingerlike extensions of the plasma membrane. They are common on apical surfaces of epithelium. They tremendously increase the exposed surface area. In epithelia, they absorb or secrete substances. -They are often so dense that the cell apices have a brush border.

squamous cells

flattened and scale-like. Their nuclei is also flattened.

tubuloalveolar

if they have both types of secretory units.

transitional epithelium

forms the lining of hollow urinary organs, which stretch as they fill with urine. Cells of its basal layer are cuboidal or columnar. The apical cells vary in appearance, depending on the degree of distention of the organ. When distension occurs, this type of epithelium thins from about 6 layers to 3, and its domelike apical cells flatten and become squamous like.

apocrine glands

glands that accumulate their products, but in this case only just beneath the free surface. There is some controversy over whether humans have this third gland type. Eventually, the apex of the cell pinches off (apo = from, off), releasing the secretory granules and a small amount of cytoplasm. The cell repairs its damage and the process repeats again and again.

merocrine glands

glands that secrete their products by exocytosis as they are produced. The secretory cells are not altered in any way. The pancreas, most sweat glands, and salivary glands belong to this class. -They secrete their products by exocytosis -This also belongs in the multicellular exocrine glands.

exocrine glands

glands that secrete their products onto body surfaces or into body cavities. They are a diverse lot and many of their products are familiar. They include mucous, sweat, oil, and salivary glands, the liver (secretes bile), the pancreas, and many others.

Tissues

groups of cells that are similar in structure and perform a common or related function. -Four primary tissue types: epithelial, nerve, muscle, and connective.

Connective tissue proper

has two subclasses: loose connective tissues and dense connective tissues.

compound glands

have a branched duct.

simple glands

have an un-branched duct

muscle tissues

hifhly cellular, well-vascularized tissues that are responsible for most types of body movement. They posses myofilaments, which are elaborate versions of the actin and myosin filaments that bring about movement or contraction in all cell types. Three kinds: skeletal, cardiac, and smooth.

neurons

highly specialized nerve cells that generate and conduct nerve impulses. Typically, they are branching cells with cytoplasmic extensions or processes that enable them to respond to stimuli and transmit electrical pulses over substantial distances within the body.

alveolar

if the secretory cells form small, flask like sacs

tubular

if the secretory cells form tubes

lamina propria

in mucous membranes, this is where the epithelia sheet lies directly over a layer of loose connective tissue. In some mucosae, this rests on a third (deeper) layer of smooth muscle cells.

fibrocartilage

intermediate betwee hyaline cartilage and dense regular connective tissues. Compressible and resists tension well. It is found where strong support and the ability to withstand heavy pressure are required.

macrophages

large, irregularly shaped cells that avidly phagocytize a broad variety of foreign materials, ranging from foreign molecules to entire bacteria to dust particles. "big eaters"

osteocytes

mature bone cells, reside in the lacunae within the matrix they have made.

chondrocytes

mature cartilage cells, typically found in small groups within cavities called lacunae.

-cyte

mature, less active mode. These cells maintain the health of the matrix.

unicellular glands

mucous cells and goblet cells. They are sprinkled in the epithelial linings of the intestinal and respiratory tracts amid columnar cells with other functions.

skeletal muscle

muscle cell packaged by connective tissue sheets into organs that are attached to the bones of the skeleton. These muscles form the flesh of the body, and as they contract they pull on bones or skin, causing body movements. *voluntary muscle

cardiac muscle

muscle tissue found only in the walls of the heart. Its contractions help propel blood through the blood vessels to all parts of the body. The cells are striated, however they generally only have one nucleus and they have intercalated discs. *involuntary muscle

elastic cartilage

nearly identical to hyaline cartilage. except is has many more elastic fibers. They are found where strength and exceptional stretchability are needed. Forms the "skeletons" of the external ear and the epiglottis (the flap that covers the opening to the respiratory passageway when we swallow)

White blood cells

neutrophils, eosinophils, lymphocytes, and other cells types that are concerned with tissue response to injury.

supporting cells

nonconducting cells that support, insulate, and protect delicate neurons.

regeneration

replaces destroyed tissue with the same kind of tissue

reticular connective tissue

resembles areolar connective tissue, but the only fibers in its matrix are reticular fibers, which form a delicate network along fibroblasts that are scattered.

dense irregular connective tissue

same structural elements as the regular variety. However, the bundles of collagen fibers are much thicker and they are arranged irregularly. It forms in sheets in body areas where tension is exerted from many different directions. -It is found in the skin as the leathery dermis, and it forms fibrous joint capsules and the fibrous coverings that surround some organs.

holocrine glands

secretory cells of this type of gland accumulate their products within them until they rupture. Once the entire secretory cell ruptures, they release secretions and dead cell fragments. -This also belongs in the multicellular exocrine glands.

adipose tissue

similar to areolar tissue in structure and function, but its nutrient-storing ability is much greater. Adipocytes account for 90% of this tissue's mass. Richly vascularized, indicating its high metabolic activity. It is abundant, accounts for 18% of an average person's body weight. It usually develops in subcutaneous tissue where it acts as a shock absorber, as insulation, and as an energy storage site. This is usually called white fat, but there is also brown fat.

muscle fibers

skeletal muscle cells; long, cylindrical cells that contain many peripherally located nuclei. They are banded and appearance reflects the precise alignment of their myofilaments.

cilia

some epithelia, such as the lining of the trachea, have these tiny hairlike projections that proper substances along their surface.

epithelia

special characteristics of this tissue include, polarity, specialized contacts, supported by connective tissue, avascular but innervated, and regeneration.

Tissue repair

steps include inflammation, organization, and regeneration and fibrous repair

multicellular exocrine glands

structurally more complex than unicellular glands. They have two basic parts: an epithelium-derived duct and a secretory unit consisting of secretory cells. They can be classified by structure and by type of secretion. They secrete their products in different ways, so they are described functionally as merocrine, holocrine, or apocrine.

histology

study of tissues. Complements the study of gross anatomy.

columnar cells

tall and column shaped. The nuclei is elongated from top to bottom and is usually located closer to the cell base.

Goblet cells

the cuplike accumulation of mucin distends the top of the cell, making the cells look like a glass with a stem. This distortion does not occur in mucous cells.

blood

the fluid within blood vessels. The most atypical connective tissue. It does not connect things or give mechanical support. It develops from mesenchyme and consists of blood cells, surrounded by a nonliving fluid matrix called blood plasma.

nervous tissue

the main component of the nervous system--the brain, spinal cord, and nerves--which regulates and controls body functions. Two major cell types are neurons and supporting cells.

Connective Tissue

the most abundant and widely distributed of the primary tissues, but its amount in particular organs varies. -Four main classes: 1. connective tissue proper, 2. cartilage, 3. bone, 4. blood. -Major functions include: 1. binding and supporting, 2. protecting, 3. insulating, 4. storing reserve fuel, 5. transporting substances within the body. -Structural elements include: 1. ground substance, 2. fibers, 3. cells.

Stratified squamous epithelium

the most widespread of this tissue type. It is composed of several layers, it is thick and well suited for its protective role in the body. Its free surface cells are squamous and the cells of the deeper layers are cuboidal or columnar. This epithelium is found in areas subjected to wear and tear and its surface cells are constantly being rubbed away and replaced by division of its basal cells. * this epithelium forms the external part of the skin and extends to a short distance into every body opening that is directly continuous with the skin. -This layer of tissues is nonkeratinized.

chondroblasts

the predominant cell type in growing cartilage, produce new matrix until the skeleton stops growing at the end of adolescence.

simple squamous epithelium

these cells are flattened laterally, and their cytoplasm is sparse. They allow material to pass by diffusion and filtration in sites where protection is not important. They also secrete lubricating substances in serosae. It is thin and often permeable. -In the kidneys, it forms part of the filtration membrane. -In the lungs, it forms the walls of the air sacs across which gas exchange occurs. -other locations, lining of heart, blood vessels and lymphatic vessels, and lining of ventral body cavity (serosae).

osetoblasts

these produce the organic portion of the matrix, ad then bone salts are deposited on and between the fibers,

Stratified epithelia

these tissues contain two or more cell layers. They regenerate from below. They are considerably more durable than its counter, and protection is their major (but not their only) role.

brown adipose tissue

this fat tissue contains abundant mitochondria, which use the lipid fuels to heat the bloodstream to warm the body (rather than produce ATP molecules). It occurs mainly on the back of babies who lack the ability to produce body heat by shivering.