bio 141 exam 3 jscc

Finger prints

. Friction ridges are the markings on the fingertips that leave distinctive oily fingerprints on surfaces we touch.

Most of the skin is ___________ mm thick.

1 to 2

fibers

Muscle cells and axons are often called ______ because of their shape.

lacunae

Osteocytes and chondrocytes occupy little cavities called ______.

dermal papiliae

Projections of the dermis toward the epidermis are called .

Psoriasis

Recurring, reddened plaques covered with silvery scale; sometimes disfiguring; possibly caused by an autoimmune response; runs in families.

______________ epithelium allows for rapid diffusion of oxygen and carbon dioxide through the air sacs (alveoli) of the lungs.

Simple squamous

are skin cells with a sensory role.

Tactile cells

collagen

Tendons and ligaments are made mainly of the protein ______.

sebaceous glands

The holocrine glands that secrete into a hair follicle are called .

Squamous

The most widespread epithelium in the body is stratified squamous epithelium, which deserves further discussion. Its deepest layer of cells are cuboidal to columnar, and include mitotically active stem cells. Their daughter cells push toward the surface and become flatter (more scaly) as they migrate farther upward, until they finally die and flake off.

skeletal muscle

The only type of muscle that lacks gap junctions is ______.

debridement

The process of removing burned skin from a patient is called .

mesothelium

The simple squamous epithelium that lines the peritoneal cavity is called ______.

______ prevent fluids from seeping between epithelial cells.

Tight junctions

The external surface of the stomach is covered by

a serosa.

Which of the following is a scent gland?

apocrine gland

Which of the following terms is least related to the rest?

cortex

Which of the following skin cells alert the immune system to pathogens?

dendritic cells

Tendons are composed of ______ connective tissue.

dense regular

Which of these is a primary germ layer?

ectoderm

The _______________ gives rise to the _______________.

ectoderm; nervous system and epidermis

The shape of the external ear is due to

elastic cartilage.

The basement membrane is found between

epithelium and connective tissue.

The most abundant formed element(s) of blood is/are

erythrocytes.

The collagen of areolar tissue is produced by

fibroblasts.

These are all types of cells found in the epidermis except

fibroblasts.

The four primary tissue types found in adult organs include all of the following

fibrous.

Skin covering the __________ has sweat glands but no hair follicles or sebaceous (oil) glands.

fingertips

mesenchyme

form of embryonic connective tissue. The mature connective tissues fall into four broad categories: fibrous connective tissue, adipose tissue, supportive connective tissues (cartilage and bone), and fluid connective tissue (blood). Mesoderm eventually turns to a gelatinous tissue called mesenchyme, composed of fine, wispy collagen (protein) fibers and branching mesenchymal cells embedded in a gelatinous ground substance. Mesenchyme gives rise to muscle, bone, and blood among other tissues

The clear gel inside a cell is called

interstitial fluid

Epidermis

is a keratinized stratified squamous epithelium, as described in chapter 5. That is, its surface consists of dead cells packed with the tough protein keratin. Like other epithelia, the epidermis lacks blood vessels and depends on the diffusion of nutrients from the underlying connective tissue. It has sparse nerve endings for touch and pain, but most sensations of the skin are due to nerve endings in the dermis. Layers of the Epidermis 1. The stratum basale (bah-SAY-lee) consists mainly of a single layer of cuboidal to low columnar stem cells and keratinocytes resting on the basement membrane. Scattered among these are the melanocytes, tactile cells, and stem cells. As the stem cells divide, they give rise to keratinocytes that migrate toward the skin surface and replace lost epidermal cells. The life history of these cells is described in the next section. 2. The stratum spinosum (spy-NO-sum) consists of several layers of keratinocytes. In most skin, this is the thickest stratum, but in thick skin it is usually exceeded by the stratum corneum. The deepest cells of the stratum spinosum remain capable of mitosis, but as they are pushed farther upward, they cease dividing. Instead, they produce more and more keratin filaments, which cause the cells to flatten. Therefore, the higher up you look in the stratum spinosum, the flatter the cells appear. Dendritic cells are also found throughout the stratum spinosum, but are not usually identifiable in routinely stained tissue sections. The stratum spinosum is named for an artificial appearance (artifact) created by the histological fixation of tissue specimens. Keratinocytes are firmly attached to each other by numerous desmosomes, which partly account for the toughness of the epidermis. Histological fixatives shrink the keratinocytes so they pull away from each other, but they remain attached by the desmosomes—like two people holding hands while they step farther apart. The desmosomes thus create bridges from cell to cell, giving each cell a spiny appearance from which we derive the word spinosum. Epidermal keratinocytes are also bound to each other by tight junctions, which make an essential contribution to water retention by the skin. This is further discussed in the next section. 3. The stratum granulosum consists of three to five layers of flat keratinocytes—more in thick skin than in thin skin. The keratinocytes of this layer contain coarse, dark-staining keratohyalin granules that give the layer its name. The functional significance of these granules will be explained shortly. 4. The stratum lucidum5 (LOO-sih-dum) is a thin zone superficial to the stratum granulosum, seen only in thick skin. Here, the keratinocytes are densely packed with a clear protein named eleidin (ee-LEE-ih-din). The cells have no nuclei or other organelles. This zone has a pale, featureless appearance with indistinct cell boundaries. 5. The stratum corneum consists of up to 30 layers of dead, scaly, keratinized cells that form a durable surface layer. It is especially resistant to abrasion, penetration, and water loss. .

Dense regular connective tissue

is named for two properties: (1) the collagen fibers are closely packed and leave relatively little open space, and (2) the fibers are parallel to each other. It is found especially in tendons and ligaments. The parallel arrangement of fibers is an adaptation to the fact that tendons and ligaments are pulled in predictable directions by musculoskeletal stresses. With minor exceptions such as blood vessels and sensory nerve fibers, the only cells in this tissue are fibroblasts, visible by their slender, violet-staining nuclei squeezed between bundles of collagen. This type of tissue has few blood vessels, so injured tendons and ligaments are slow to heal.

Nervous tissue

is specialized for communication by means of electrical and chemical signals. It consists of neurons (NOOR-ons), or nerve cells, and a much greater number of neuroglia (noo-ROG-lee-uh), or glial (GLEE-ul) cells, which protect and assist the neurons. Neurons detect stimuli, respond quickly, and transmit coded information rapidly to other cells

Insensible Perspiration

is sweating without noticeable wetness of the skin.

Which of the following skin conditions or appearances would most likely result from liver failure?

jaundice

All of the following interfere with microbial invasion of the body except

melanization.

Which of the following glands produce the acid mantle?

merocrine sweat glands

Bone

or osseous tissue (table 5.8, fig. 5.22) is a hard, calcified connective tissue that composes the skeleton. The term bone has two meanings in anatomy—an entire organ such as the femur and mandible, or just the osseous tissue. Bones are composed of not only osseous tissue, but also cartilage, bone marrow, dense irregular connective tissue, and other tissue types.

The epidermal water barrier is formed at the point where epidermal cells

pass from stratum spinosum to stratum granulosum

Stratified

range from 2 to 20 or more layers of cells, with some cells resting directly on others and only the deepest layer attached to the basement membrane.

An epithelium with all cells tall and narrow and with every cell touching the basement membrane is called ________________

simple columnar.

Most kidney tubules are made of this tissue specialized for absorption and secretion

simple cuboidal epithelium

A thin, stained slice of tissue mounted on a microscope is called a

stain

A fixative serves to

stop tissue decay.

A seminiferous tubule of the testis is lined with ______ epithelium.

stratified cuboidal

Cells of the are keratinized and dead

stratum corneum

The skin does not include

the hypodermis.

Transitional epithelium is found in

the urinary system

Areolar

tissue exhibits loosely organized fibers, abundant blood vessels, and a lot of seemingly empty space. It possesses all six of the aforementioned cell types. Its fibers run in random directions and are mostly collagenous, but elastic and reticular fibers are also present. Areolar tissue is highly variable in appearance. In many serous membranes, it looks like figure 5.14, but in the skin and mucous membranes, it is more compact (see fig. 5.8) and sometimes difficult to distinguish from dense irregular connective tissue. Some advice on how to tell them apart is given after the discussion of dense irregular connective tissue. Areolar tissue is found in tissue sections from almost every part of the body. It surrounds blood vessels and nerves and penetrates with them even into the small spaces of muscle, tendon, and other tissues. Nearly every epithelium rests on a layer of areolar tissue, whose blood vessels provide the epithelium with nutrition, waste removal, and a ready supply of infection-fighting leukocytes in times of need. Because of the abundance of open, fluid-filled space, leukocytes can move about freely in areolar tissue and can easily find and destroy pathogens.

The hair on a 6-year-old's arms is

vellus.

Muscle tissue

—skeletal, cardiac, and smooth—which differ in appearance, physiology, and function (table 5.11, figs. 5.25 to 5.27). Skeletal muscle consists of long threadlike cells called muscle fibers consists of long threadlike cells called muscle fibers. Most skeletal muscle is attached to bones, but there are exceptions in the tongue, upper esophagus, some facial muscles, and some sphincter25 (SFINK-tur) muscles (muscular rings or cuffs that open and close body passages). Each cell contains multiple nuclei adjacent to the plasma membrane. Skeletal muscle is described as striated and voluntary. The first term refers to alternating light and dark bands, or striations (stry-AY-shuns), created by the overlapping pattern of cytoplasmic protein filaments that cause muscle contraction. The second term, voluntary, refers to the fact that we usually have conscious control over skeletal muscle. Cardiac muscle is limited to the heart. It too is striated, but it differs from skeletal muscle in its other features. Its cells are much shorter, so they are commonly called myocytes26 or cardiocytes rather than fibers. The myocytes are branched or notched at the ends. They contain only one nucleus, which is located near the center and often surrounded by a light-staining region of glycogen. Cardiac myocytes are joined end to end by junctions called intercalated27 (in-TUR-kuh-LAY-ted) discs. Electrical connections at these junctions enable a wave of excitation to travel rapidly from cell to cell, and mechanical connections keep the myocytes from pulling apart when the heart contracts. The electrical junctions allow a wave of electrical excitation to travel rapidly from cell to cell so that all the myocytes of a heart chamber are stimulated and contract almost simultaneously. Intercalated discs appear as dark transverse lines separating each myocyte from the next. They may be only faintly visible, however, unless the tissue has been specially stained for them. Cardiac muscle is considered involuntary because it is not usually under conscious control; it contracts even if all nerve connections to it are severed. Smooth muscle lacks striations and is involuntary. Smooth muscle cells, also called myocytes, are fusiform and relatively short. They have only one, centrally placed nucleus. Small amounts of smooth muscle are found in the iris of the eye and in the skin, but most of it, called visceral muscle, forms layers in the walls of the digestive, respiratory, and urinary tracts; blood vessels; the uterus; and other viscera. In locations such as the esophagus and small intestine, smooth muscle forms adjacent layers, with the cells of one layer encircling the organ and the cells of the other layer running longitudinally. When the circular smooth muscle contracts, it may propel contents such as food through the organ. When the longitudinal layer contracts, it makes the organ shorter and thicker. By regulating the diameter of blood vessels, smooth muscle is very important in controlling blood pressure and flow. Both smooth and skeletal muscle form sphincters that control the emptying of the bladder and rectum.

third degree

A burn destroys the entire dermis

dermal papilla

A hair is nourished by blood vessels in a connective tissue projection called the .

piloerector

A muscle that causes a hair to stand on end is called a/an .

simple

A/An ______ adult stem cell can differentiate into two or more mature cell types.

basement membrane

An epithelium rests on a layer called the ______ between its deepest cells and the underlying connective tissue.

simple

Any epithelium in which every cell touches the basement membrane is called a/an ______ epithelium.

necrosis

Any form of pathological tissue death is called ______.

Dermis

Beneath the epidermis is a connective tissue layer, the dermis. It ranges from 0.2 mm thick in the eyelids to about 4 mm thick in the palms and soles. It is composed mainly of collagen, but also contains elastic and reticular fibers, fibroblasts, and the other cells typical of fibrous connective tissue (described in chapter 5). It is well supplied with blood vessels, cutaneous glands, and nerve endings. The hair follicles and nail roots are embedded in the dermis. In the face, skeletal muscles attach to dermal collagen fibers and produce such expressions as a smile, a wrinkle of the forehead, or the lifting of an eyebrow

Basement Membrane

Between an epithelium and the underlying connective tissue. It contains collagen, glycoproteins, and other protein-carbohydrate complexes, and blends into other proteins of the connective tissue. The basement membrane serves to anchor an epithelium to the connective tissue; it controls the exchange of materials between the epithelium and the underlying tissues; and it binds growth factors from below that regulate epithelial development.

cyansis

Blueness of the skin due to low oxygen concentration in the blood is called .

earwax

Cerumen is more commonly known as .

Tissue Repair

Damaged tissues can be repaired in two ways: regeneration or fibrosis. Regeneration is the replacement of dead or damaged cells by the same type of cells as before; it restores normal function to the organ. Most skin injuries (cuts, scrapes, and minor burns) heal by regeneration. The liver also regenerates remarkably well. Fibrosis is the replacement of damaged tissue with scar tissue, composed mainly of collagen produced by fibroblasts. Scar tissue helps to hold an organ together, but it does not restore normal function. Examples include the healing of severe cuts and burns, the healing of muscle injuries, and scarring of the lungs in tuberculosis. Severed blood vessels bleed into the cut. Mast cells and cells damaged by the cut release histamine, which dilates blood vessels, increases blood flow to the area, and makes blood capillaries more permeable. Blood plasma seeps into the wound, carrying antibodies and clotting proteins. A blood clot forms in the tissue, loosely knitting the edges of the cut together and inhibiting the spread of pathogens from the site of injury into healthy tissues. The surface of the blood clot dries and hardens in the air, forming a scab that temporarily seals the wound and blocks infection. Beneath the scab, macrophages begin to phagocytize and digest tissue debris. New blood capillaries sprout from nearby vessels and grow into the wound. The deeper portions of the clot become infiltrated by capillaries and fibroblasts and transform into a soft mass called granulation tissue. Macrophages remove the blood clot while fibroblasts deposit new collagen to replace it. This fibroblastic (reconstructive) phase of repair begins 3 to 4 days after the injury and lasts up to 2 weeks. Surface epithelial cells around the wound multiply and migrate into the wounded area, beneath the scab. The scab loosens and eventually falls off, and the epithelium grows thicker. Thus, the epithelium regenerates while the underlying connective tissue undergoes fibrosis, or scarring. Capillaries withdraw from the area as fibrosis progresses. The scar tissue may or may not show through the epithelium, depending on the severity of the wound. The wound may exhibit a depressed area at first, but this is often filled in by continued fibrosis and remodeling from below, until the scar becomes unnoticeable. This remodeling (maturation) phase of tissue repair begins several weeks after injury and may last as long as 2 years.

_______________ lines body cavities, covers the body surface, and forms the lining of many organs

Epithelial tissue

cextraceellular material

Fibers and ground substance make up the ______ of a connective tissue.

anagen

Hairs grow only during the phase of the hair cycle.

Ceruminous glands

are found only in the external ear canal, where their secretion combines with sebum and dead epidermal cells to form earwax, or cerumen.35 They are simple, coiled, tubular glands with ducts leading to the skin surface. Cerumen keeps the eardrum pliable, waterproofs the canal, kills bacteria, and coats the guard hairs of the ear, making them sticky and more effective in blocking foreign particles from entering the canal.

Burns

are the leading cause of accidental death. They are usually caused by fires, kitchen spills, or excessively hot bath water, but they also can be caused by sunlight, ionizing radiation, strong acids and bases, or electrical shock. Burn deaths result primarily from fluid loss, infection, and the toxic effects of eschar (ESS-car)—the burned, dead tissue. Burns are classified according to the depth of tissue involvement (fig. 6.13). First-degree burns involve only the epidermis and are marked by redness, slight edema, and pain. They heal in a few days and seldom leave scars. Most sunburns are first-degree burns. Second-degree burns involve the epidermis and part of the dermis but leave at least some of the dermis intact. First- and second-degree burns are therefore also known as partial-thickness burns. A second-degree burn may be red, tan, or white and is blistered and very painful. It may take from 2 weeks to several months to heal and may leave scars. The epidermis regenerates by division of epithelial cells in the hair follicles and sweat glands and around the edges of the lesion. Severe sunburns and many scalds are second-degree burns. Third-degree burns are also called full-thickness burns because the epidermis, all of the dermis, and often some deeper tissues (muscle and bone) are destroyed. (Some authorities call burns that extend to the bone fourth-degree burns.) Since no dermis remains, the skin can regenerate only from the edges of the wound. Third-degree burns often require skin grafts (see Deeper Insight 6.5). If a third-degree burn is left to itself to heal, contracture (abnormal connective tissue fibrosis) and severe disfigurement may result.

Connective Tissue

are the most abundant, widely distributed, and histologically variable of the primary tissues. They include fibrous tissue, adipose tissue, cartilage, bone, and blood. Such diverse tissues may seem to have little in common, but as a rule, their cells occupy less space than the extracellular matrix. Usually their cells are not in direct contact with each other, but are separated by expanses of matrix. Most connective tissues serve to bind organs to each other (for example, the way a tendon connects muscle to bone), form a structural framework for an organ, or support and protect organs. Connective tissues vary greatly in vascularity, from rich networks of blood vessels in the loose connective tissues to few or no blood vessels in cartilage.

Connective Tissue

• Binding of rogans. Tendons bind muscle to bone, ligaments bind one bone to another, fat holds the kidneys and eyes in place, and fibrous tissue binds the skin to underlying muscle. • Support. Bones support the body; cartilage supports the ears, nose, larynx, and trachea; fibrous tissues form the framework of organs such as the spleen. • Physical protection. The cranium, ribs, and sternum protect delicate organs such as the brain, lungs, and heart; fatty cushions protect the kidneys and eyes. Page 151 • Immune protection. Connective tissue cells attack foreign invaders, and connective tissue fiber forms a "battlefield" under the skin and mucous membranes where immune cells can be quickly mobilized against disease agents. • Movement. Bones provide the lever system for body movement, cartilages are involved in movement of the vocal cords, and cartilages on bone surfaces ease joint movements. • Storage. Fat is the body's major energy reserve; bone is a reservoir of calcium and phosphorus that can be drawn upon when needed. • Heat production. Metabolism of brown fat generates heat in infants and children. • Transport. Blood transports gases, nutrients, wastes, hormones, and blood cells.

Cyanosis

• is blueness of the skin resulting from a deficiency of oxygen in the circulating blood. Oxygen deficiency turns the hemoglobin a reddish violet color, which is lightened to blue-violet as it shows through the white dermal collagen. Oxygen deficiency can result from conditions that prevent the blood from picking up a normal load of oxygen in the lungs, such as airway obstructions in drowning and choking, lung diseases such as emphysema, and respiratory arrest. Cyanosis also occurs in situations such as cold weather and cardiac arrest, when blood flows so slowly through the skin that the tissues consume most of the blood's oxygen faster than freshly oxygenated blood arrives.