Human Anatomy Exam 1 (Ch. 4)

What are unicellular organisms?

What are unicellular organisms?

independent little creatures, each cell alone obtains and digests its food, ejects its wastes, and carries out all of the other activities necessary to keep itself alive

What are multicellular organisms?

do not operate independently, they form tight cell communities that live and work together

What are tissues?

groups of cells that are similar in structure and perform a common or related function

Four common tissue types interweave to form the _____ of the body

fabric

What are the 4 basic tissues?

epithelial, muscle, connective, and nervous

Before a specimen can be viewed through a microscope, it must be…..

1. fixed (preserved)

2. then cut into sections (slices) thin enough to transmit light or electrons

3. must be stained to enhance contrast between structures

What is an epithelial tissue/epithelium?

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

What happens in the form of covering and lining epithelium?

• forms the outer layer of the skin

• dips into and lines the open cavities of the urogenital, digestive, and respiratory systems

• covers the walls and organs of the closed ventral body cavity

What happens in the form of glandular epithelium?

fashions the glands of the body

What are the pseudostratified columnar epithelium?

the cells 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 for the pseudostratified columnar epithelium lie at different levels above the basement membrane, the tissue gives what?

the false (pseudo) impression that several cell layers are present, hence “pseudostratified”

A ciliated version containing mucus-secreting goblet cells lines most of the what?

respiratory tract

The motile cilia propel sheets of dust-trapping mucus away from what?

the lungs

What are stratified epithelial tissues?

contain two or more cell layers, regenerate from below; the basal cells divide and push apically to replace the older surface cells

Stratified epithelia are more durable than _____ epithelia, and protection is their major role (not only role)

simple

What is the stratified squamous epithelium?

most widespread of the stratified epithelium, composed of several layers making it thick and well suited for its protective role in the body

Stratified squamous epithelium’s free surface cells are ______ and cells of the deeper layers are ______ or _______

squamous, cuboidal, columnar

The stratified squamous epithelium is found in which areas?

subjected to wear and tear, and its surface cells are constantly being rubbed away and replaced by division of its basal cells

The stratified squamous epithelium forms the external surfaces of ______ and extends a short distance into every body opening that is directly continuous with the skin

skin

Which layer of the skin is keratinized, meaning its surface cells contain keratin, a tough protective protein?

outer layer, or epidermis (skin, cells lack nuclei at free surface)

The other stratified squamous epithelia of the body are _______

nonkeratinized, lines mouth and esophagus, has nuclei present at free surface

Which epithelia is rare in the body, as it is mostly found in the ducts of some of the larger glands (sweat glands, mammary glands)?

stratified cuboidal epithelium (function: lining)

The stratified cuboidal epithelia typically has _______ layers of cuboidal cells

two

Which epithelia has limited distribution in the body where small amounts are found in the pharynx, the male urethra, and lining some glandular tracts?

stratified columnar epithelium (occurs at transition areas or junctions between two types of epithelia)

Only the _____ layer of cells of the stratified columnar epithelium is columnar

apical

Transitional epithelium forms what?

the lining of hollow urinary organs (urinary bladder, ureters, and urethra), which stretch as they fill with urine

Cells of its basal layer for transitional epithelium are what?

cuboidal or columnar

The apical cells for transitional epithelium vary in what?

appearance, depending on the degree of distension (stretching) of the organ

The ability of transitional epithelium to change their shape (undergo transitions), allows what?

a greater volume of urine to flow through a tube like organ

In glandular epithelium, a gland consists of what?

one or more cells that make and secrete a particular product called a secretion, which is an aqueous fluid that usually contains proteins

Where they release their product, glands may be _______

endocrine (product released into blood) or exocrine (product released to body surface or into a duct which transports product)

Number of cells, glands may be ______

unicellular or multicellular

Because ______ ______ lose their ducts during development (ductless glands), they are often called ductless glands

endocrine glands

Endocrine glands produce ______, chemical messengers that they secrete by exocytosis directly into extracellular space

hormones

For endocrine glands, where do the hormones enter?

the blood or lymphatic fluid and travel to specific target organs, then each hormone prompts its target organ to respond in some characteristic way

What is an example of hormones in endocrine gland prompting its target organ to respond in characteristic way?

hormones produced by certain intestinal cells cause the pancreas to release enzymes that help digest food in the digestive tract

All exocrine glands secrete their products onto what?

body faces (skin) or into body cavities

For exocrine glands, the ______ glands secrete directly by exocytosis, whereas the ______ glands do so via an epithelium-walled duct that transports the secretion to the epithelial surface

unicellular, multicellular

______ glands are diverse as they include the liver (which secretes biles), the pancreas (which synthesizes digestive enzymes), sweat, oil, mucous, and salivary glands

exocrine

The most important examples of unicellular exocrine glands are which cells?

mucous and goblet

Where are the unicellular glands sprinkled in?

the epithelial linings of the intestinal and respiratory tracts amid the columnar cells with other functions

In humans, all such glands produce ______, a complex glycoprotein that dissolves in water when secreted

mucin

Compared to unicellular glands, ________ glands are structurally more complex as they have two basic parts: an epithelium duct and a secretory unit consisting of secretory cells

multicellular

What is the structural classification for multicellular glands?

they are either simple or compound

Simple glands have an ______ duct whereas the compound gland has a branched duct

unbranched

Tubular secretory unit is…..

if the secretory cells form tubes

Alveolar secretory unit is…..

if the secretory cells form small, flasklike sacs

Tubuloalveolar secretory unit is…..

if they have both types of secretory units

Most multicellular exocrine are…..

merocrine glands, which secrete their products by exocytosis as they are produced, pancreas, most sweat glands, and salivary glands belong to this class

What are holocrine glands (sebaceous)?

accumulate their products within them until they rupture and is released with product

Like holocrine glands, ______ glands accumulate their products, but in this case only just beneath the free surface

apocrine (product is released with some apical cytoplasm)

What are the four main classes of connective tissue?

connective tissue proper (includes fat and fibrous tissue of ligaments), blood, cartilage, and bone

The major functions for connective tissue are?

• binding and supporting

• protecting

• insulating

• storing reserve fuel

• transporting substances within the body

What is an example of connective tissue for the main classes?

• bone and cartilage support and protect body organs by providing the hard underpinnings of the skeleton

• fat insulates and protects body organs and provides a fuel reserve

• blood transports substances inside the body

Connective tissues consist largely of nonliving _____ ______

extracellular matrix, which separates the living cells of the tissues

For common origin, all connective tissues arise from ______

mesenchyme

One difference between different types of connective tissues is how richly they are supplied by _____ ______

blood vessels

cartilage is _______ , dense connective tissue is poorly ________, and the other types of connective tissue have a rich supply of blood vessels

avascular, vascularized

What are the three main components for connective tissues?

ground substance, fibers, and cells

Together, which two make up the extracellular matrix for connective tissue?

ground substance and fibers

What is the result of connective tissues using the composition and arrangement of the three components?

diversity, and each are adapted to perform a specific function in the body

What is ground substance?

the unstructured material that fills the space between the cells and contains the fibers

3 components: interstitial fluid, cell adhesion proteins, and proteoglycans

What does the interstitial fluid for ground substance consist of?

large amounts of fluid and functions as a molecular sieve through which nutrients and other dissolved substances can diffuse between the blood capillaries and the cells

What do the cell adhesion proteins serve as?

a connective tissue glue that allows connective tissue cells to attach to the extracellular matrix

What do the proteoglycans consist of?

a protein core to which large polysaccharides called glycosaminoglycans are attached, traps water in varying amounts, affects viscosity (the higher the glycosaminoglycans content, the more viscous the ground substance)

Which fibers are the strongest and more abundant?

collagen