AP Chapter 5

glial cells

(or supporting cells), which do not transmit nerve impulses but instead are responsible for the protection, nourishment, and support of the neurons(larger number)

adherent glycoproteins

(proteins with carbohydrates attached), which act like glue to bond connective tissue cells and fibers to the ground substance

All epithelia exhibit the following common characteristics

Cellularity. Epithelial tissue is composed almost entirely of tightly packed cells. Polarity. An epithelium has an apical surface (microvilli or cilia) Additionally, each epithelium has a basal surface, where the epithelium is attached to the underlying connective tissue. Attachment to a basement membrane. The epithelial layer is bound at its basal surface to a thin basement membrane (form a selective molecular barrier between the epithelium and the underlying connective tissue). All epithelial tissues lack blood vessels, nutrients for epithelial cells are obtained either directly across the apical surface or by diffusion across the basal surface from blood vessels within the underlying connective tissue. Epithelia are richly innervated (supplied with nerves) to detect changes in the environment at that body or organ region. High regeneration capacity

Epithelia have several functions including,

Physical protection, Selective permeability, Secretions, Sensations,

The many types of connective tissue collectively perform a wide variety of functions, including

Physical protection, Support and structural framework, Binding of structures, Storage, Transport, Immune protection

Do the cells have striations?

Skeletal and cardiac muscle have striations, but smooth muscle does not. Further, only cardiac muscle has intercalated discs between the cells.

What is the shape of the cell?

Skeletal muscle cells are long and cylindrical, cardiac muscle cells are short and bifurcated, and smooth muscle cells are spindle-shaped.

How many nuclei are present, and are the nuclei centrally located or at the periphery of the cell?

Skeletal muscle has multiple nuclei that are located at the periphery of the cell. Cardiac muscle has one or two centrally located nuclei. Smooth muscle has a single centrally located nucleus.

elastic cartilage

Structure Abundant elastic fibers that form weblike mesh; chondrocytes in lacunae; perichondrium present Function Maintains shape while permitting extensive flexibility

Adipose connective tissue

Structure Closely packed adipocytes; nucleus pushed to edge of cell by large fat droplet; contains many blood vessels Function Stores energy; insulates, cushions, and protects

dense irregular connective tissue

Structure Collagen fibers randomly arranged and clumped together; fibroblasts in spaces among fibers; more ground substance than in dense regular connective tissue; extensive blood supply Function Withstands stresses applied in all directions; durable

dense regular connective tissue

Structure Densely packed, parallel arrays of collagen fibers; fibroblasts squeezed between layers of fibers; scarce ground substance; greatly reduced blood supply Function Attaches bone to bone (ligament) as well as muscle to bone (tendon); resists stress applied in one direction

hyaline cartilage

Structure Glassy-appearing matrix; irregularly arranged chondrocytes in lacunae; usually covered by perichondrium Function Provides support; forms most of fetal skeleton

elastic connective tissue

Structure Predominantly composed of elastic fibers; fibroblasts occupy some spaces between fibers Function Allows for stretching and recoil

fibrocartilage

Structure Readily visible, numerous parallel collagen fibers; large chondrocytes in lacunae; no perichondrium Function Resists compression; acts as shock absorber in some joints

Reticular connective tissue

Structure Viscous ground substance; scattered arrangement of reticular fibers, leukocytes, and some fibroblasts Function Provides stroma (supportive framework) to lymphatic organs

skeletal muscle

Structure and characteristics Long, cylindrical, striated fibers (cells) arranged parallel and unbranched; fibers are multinucleated; fiber is under voluntary control Function Primarily responsible for moving skeleton and selected other components of the body

smooth muscle

Structure and characteristics Nonstriated cells that are short and fusiform in shape; contain one centrally located nucleus; under involuntary control Function Moves and propels materials through internal organs; controls the size of the lumen

cardiac muscle

Structure and characteristics Short, striated cells typically branching; cells contain one or two centrally located nuclei; intercalated discs between cells; under involuntary control Function Pumps blood through heart

serous membrane

The membrane is composed of a simple squamous epithelium called mesothelium. Serous membranes produce a thin, watery serous fluid, or transudate, which is derived from blood plasma. Serous membranes form two associated layers: a parietal layer that lines the inside of the body cavity and a visceral layer that covers the surface of the internal organs. Between these two layers is a serous cavity, which is a potential space into which the serous fluid is secreted. not open to outside

Loose connective tissue

The protein fibers are sparse and irregularly arranged, and there is abundant, viscous ground substance. Loose connective tissues act as the body's "packing material" by supporting and surrounding structures and organs.

histology

The study of tissues

transitional.

These cells can readily change their shape from polyhedral to more flattened, depending upon the degree to which the epithelium is stretched (stratified)

Reticular fibers

These fibers form a branching, interwoven framework that is tough but flexible.

If the secretory portion forms an expanded sac, the gland is called ______.

acinar

mucous membrane,

also called a mucosa (mū-kō′să), lines passageways and compartments that eventually open to the external environment; these include the digestive, respiratory, urinary, and reproductive tracts. Mucous membranes perform absorptive, protective, and secretory functions, or a combination of these functions.

cutaneous membrane

also known as the skin, which covers the external surface of the body. largest body membrane

Other leukocytes

also migrate through the blood vessel walls into the connective tissue. These include neutrophils, a type of leukocyte that phagocytizes bacteria, and T-lymphocytes, a type of leukocyte which attacks foreign materials.

perichondrium has two distinct layers:

an outer fibrous layer and an inner cellular layer

Adipocytes, also called fat cells,

appear in small clusters within some types of connective tissue proper. If large clusters of these cells dominate an area, the connective tissue is called adipose connective tissue.

Compact bone

appears completely solid, but is in fact perforated by a number of neurovascular canals. It has a uniform histologic pattern. Compact bone is formed from cylindrical structures called osteons, which display concentric rings of bone connective tissue called lamellae.

Mesenchymal cells

are a type of embryonic stem cell within connective tissue. If the tissue becomes damaged, these cells will divide. One cell that is produced replaces the mesenchymal stem cell, while the other cell becomes a committed cell that moves into the damaged area and differentiates into the type of connective tissue cell that is needed

Glands

are either individual cells or multicellular organs composed predominantly of epithelial tissue. They secrete substances

Body membranes

are formed from an epithelial layer that is bound to an underlying connective tissue

Plasma cells

are formed when B-lymphocytes are activated by exposure to foreign materials. Plasma cells produce antibodies, which are proteins that immobilize a foreign material and prevent it from causing further damage.

Free macrophages

are mobile, phagocytic cells that wander through the connective tissue. They function like fixed macrophages, yet they are able to move throughout the tissue.

Fibroblasts

are relatively flat cells with tapered ends and are the most abundant resident cells in connective tissue proper. They produce the fibers and ground substance components of the extracellular matrix.

Fixed macrophages

are relatively large, irregular-shaped cells that are derived from a type of white blood cell called a monocyte. They are dispersed throughout the matrix, where they phagocytize (engulf) damaged cells or pathogens

Mast cells

are small, mobile cells that usually are found close to blood vessels; they secrete heparin to inhibit blood clotting and histamine to dilate blood vessels and increase blood flow, which is significant in the inflammatory response.

Resident cells

are stationary cells that are permanently housed within the connective tissue. They help support, maintain, and repair the extracellular matrix

Collagen fibers

are unbranched, "cablelike" long fibers that are strong, flexible, and resistant to stretching. These fibers are stronger than steel of the same diameter. pink or white

There are three types of loose connective tissue:

areolar connective tissue, adipose connective tissue, and reticular connective tissue.

mature cartilage is _____, and as a result the chondrocytes must exchange nutrients and waste products by diffusion with blood vessels outside of the cartilage.

avascular

There are two types of fluid connective tissue:

blood and lymph

There are two types of supporting connective tissue:

cartilage and bone

All connective tissues share three basic components:

cells, protein fibers, and ground substance

Three basic types of protein fibers may be found in connective tissue:

collagen fibers, reticular fibers, and elastic fibers.

columnar

column (oval nucleus)

The extracellular matrix is

composed of varying amounts of protein fibers, water, and dissolved molecules (e.g., glucose, oxygen). Its consistency ranges from fluid to semisolid to solid.

multicellular exocrine glands

contain numerous cells that work together to produce a secretion

elastic fibers

contain the protein elastin. The fibers branch and rejoin, and appear wavy. Elastic fibers stretch and recoil easily. yellow

Wandering cells

continuously move throughout the connective tissue proper and are components of the immune system. They also may help repair damaged extracellular matrix. These cells are primarily types of leukocytes, also known as white blood cells, and protect the body against harmful agents.

cuboital

cube (sphere nucleus)

There are three categories of dense connective tissue:

dense regular connective tissue, dense irregular connective tissue, and elastic connective tissue.

Tissues in the body are classified into four major types:

epithelial tissue, connective tissue, muscle tissue, and nervous tissue

squamous

flat (flat nucleus)

a scattering of unicellular glands called ____ _____

goblet cells

tissue

groups of similar cells and extracellular material that perform a common function, such as providing protection or facilitating body movement.

Cartilage

has a firm, semisolid extracellular matrix that contains variable amounts of collagen and elastic protein fibers. Mature cartilage cells are called chondrocytes. These cells occupy small spaces called lacunae within the extracellular matrix. Most cartilage is surrounded by a dense irregular connective tissue covering called the perichondrium

Areolar connective tissue

has a loosely unconfined organization of collagen and some elastic fibers and is highly vascularized. This connective tissue type contains all of the fixed and wandering cells of connective tissue proper, although the predominant cell is the fibroblast. The ground substance is abundant and viscous.

Finally, some spongy bone houses _______ cells, which form a type of reticular connective tissue that makes blood cells (a process called hemopoiesis).

hemopoietic

Three major types of cartilage are found in the body:

hyaline cartilage, fibrocartilage, and elastic cartilage

tubular

if the secretory portion and the duct have the same diameter

Cardiac muscle cells are considered ______ because they cannot be controlled by the somatic (voluntary) nervous system activity to initiate a contraction

involuntary

Blood

is a fluid connective tissue composed of formed elements. Formed elements include cells, both erythrocytes (red blood cells) and leukocytes (white blood cells), and cellular fragments called platelets. The liquid ground substance is called plasma, and within it are dissolved proteins.

Ground substance

is a noncellular material produced by the connective tissue cells. the connective tissue cells and protein fibers reside. The ground substance may be viscous (as in blood), semisolid (as in cartilage), or solid (as in bone). Together, the ground substance and the protein fibers it houses form an extracellular matrix.

GAG

is a polysaccharide that is composed completely of carbohydrate building blocks, some of which have an attached amine group. GAGs are negatively charged and hydrophilic

Bone connective tissue

is also known as osseous connective tissue. Bone is more solid than cartilage and provides greater support, although it is not as flexible. The extracellular matrix of bone connective tissue consists of organic components (collagen fibers and glycoproteins) and inorganic components composed of a mixture of calcium salts, primarily calcium phosphate.

epithelial tissue,

is composed of one or more layers of closely packed cells, and it contains little to no extracellular matrix between these cells. Epithelial tissue covers the body surfaces, lines the body cavities and organ cavities, and forms most glands.

Dense connective tissue

is composed primarily of protein fibers and has proportionately less ground substance than loose connective tissue. It also is known as collagenous tissue because collagen fibers usually are the dominant fiber type.

Lymph

is derived from blood plasma, but it contains no cellular components or fragments

Spongy bone

is located within the interior of a bone, and it contains a latticework structure of bone connective tissue that is very strong, yet lightweight

Mesenchyme

is the first type of connective tissue to emerge in the developing embryo. It has star-shaped (stellate) or spindle-shaped mesenchymal cells dispersed within a gel-like ground substance that contains fine, immature protein fibers

mesothelium

is the name given to the simple squamous epithelium that forms the serous membranes of body cavities

Endothelium

is the name of the simple squamous epithelium that lines both blood vessels and lymph vessels

Endocrine glands

lack ducts and secrete their products, called hormones, directly into the blood. Hormones act as chemical messengers to influence cell activities

Connective tissue proper is divided into two broad groups:

loose connective tissue and dense connective tissue.

A second type of embryonic connective tissue is ___ ____ _____, also known as Wharton's jelly. The immature protein fibers in this tissue are more numerous than those within mesenchyme. located within the umbilical cord only.

mucous connective tissue

stratified epith

multiple layers

stratified squamous can be ____ and ______

non-keratinized(superficial cells are not dead) or keratinized(superficial cells are dead)

simple epith.

one layer

pseudostratified epith.

one layer of tall cells that appear stratified(simple)

The bone cells are called ______ and are housed within spaces in the extracellular matrix called lacunae.

osteocytes

When a GAG is linked to a protein, it forms an even larger molecule within the ground substance called a ________.

proteoglycan. Proteoglycans have over 90% of their structure composed of carbohydrates, in the form of GAGs. The large structure of a proteoglycan is due primarily to the large number of negative charges in its GAGs, which then repel each other and cause the molecule to spread out and occupy more space.

neurons

receive, transmit, and process nerve impulses

Connective tissue proper contains two classes of cells:

resident cells and wandering cells.

The three types of muscle tissue are

skeletal muscle, cardiac muscle, and smooth muscle

Under the light microscope, skeletal muscle fibers exhibit alternating light and dark bands, called ______, that reflect the overlapping pattern of parallel thick and thin contractile protein filaments

striations

Connective tissue functions to

support, protect, and bind organs.

1. Cells that form fibers and ground substance in the extracellular matrix Fibroblasts correct 2. Cells that maintain their fibers and ground substance in the extracellular matrix Fibrocytes correct 3. Cells that form bone Osteoblast correct 4. Cells that maintain bone Osteocytes correct 5. Cells that break down bone Osteoclasts correct 6. Cells that store lipids Adipocytes correct 7. Cells that can move and ingest foreign substances Macrophages correct 8. Cells that are nonmotile and release inflammatory chemicals Mast cells correct

t/f A blood vessel consists of epithelial, connective, muscle, and nervous tissue; therefore, it can be classified as an organ. TRUE

synovial membrane

that is composed of a superficial layer of squamous epithelial cells that lack a basement membrane and rests on an areolar connective tissue layer. The epithelial cells secrete a synovial fluid that reduces friction among the moving bone parts and distributes nutrients to the cartilage on the articular surfaces of bone

a gland with both tubules and acini is called a _____ _____

tubuloacinar gland

Unicellular exocrine glands

typically do not contain a duct, and they are located close to the surface of the epithelium in which they reside

Exocrine glands

typically originate from an invagination of epithelium that burrows into the deeper connective tissues. These glands usually maintain their connection with the epithelial surface by means of a duct,

skeletal muscle is considered ________because it usually does not contract unless stimulated by the somatic (voluntary) nervous system

voluntary

intercalated discs,

which are intercellular junctions between the cells composed of desmosomes and gap junctions

acini

which are the clusters of cells that produce the secretion

mucin

which is a glycoprotein that when hydrated (mixed with water) forms mucus

keratin

which is a tough, protective protein that strengthens the tissue