A&P: Ch. 5 Tissues

absorptive cell

cell commonly found in the small intestine that can absorb nutrients from the luminal surface via phagocytosis and pinocytosis; have large surface area as a result of the presence of microvilli

acinar (alveolar) gland

secretory units of exocrine glands that contain one or more saclike structures

adipocyte

type of fixed cell in the connective tissue that stores fat (lipids) in its cytoplasm. Nucleus and other organelles are pushed to the periphery of the cell.

apical surface

side of an epithelial cell that faces in toward the body cavity

aprocrine gland

gland whose secretions contain some of its cellular material. Part of the secretory cell is destroyed and must regenerate before the cell can secrete again. ex) mammary glands and some sweat gland

areolar connective tissue

soft, spongy connective tissue, also known as loose connective tissue. Located throughout the body and is composed of a soft ground substance, numerous cell types (WBC, fibroblasts, macrophages), and all three types of fiber (elastic, reticular, and collagenous)

articular cartilage

thin layer of hyaline cartilage that covers the articular surfaces of long bones in synovial joints. Forms a smooth layer over the joint surfaces of the bones, which decreases friction and allows free joint movement.

avascular

without a blood supply

axon

extension of the neuron that conducts the nerve impulse away from the cell body to the terminal bouton (synaptic bulb) at the end of the neuron

basal surface

side of epithelial cell that faces a lower level of connective tissue

basement membrane

noncellular, collagen-based structure that supports epithelial tissue

blast

cell in the production stage of a particular substance

broad ligament

paired sheets of connective tissue that suspend the uterus from the dorsal part of the abdominal cavity and attach it to the abdominal wall. Often subdivided into the mesovarium, which supports the ovary; mesosalpinx, the oviduct; mesometrium, the uterus

brown adipose tissue

commonly found throughout the body of hibernating species and neonates. Specialized form that releases its stored lipid reserves in the form of heat.

brush border

microvilli on the free surfaces of intestinal epithelial cells and kidney tubule cells that resemble the bristles of a brush

calcified

hardening of organic tissue by the deposit of lime and calcium salts

canaliculi

tiny channels through the matrix of bone. Threadlike projections from osteocytes communicate with each other and with blood vessels through it

cartilage

opaque, dense connective tissue composed of a relatively small number of cells that are contained within a nonliving matrix. Absorbs shock and protects the epiphysial ends of bones. Not innervated or vascularized, which makes it resistant to pain but also to healing.

chondroblast

fixed cells that form cartilage

chondrocyte

mature cartilage cell

chondroitin sulfate

glycosaminoglycan found in cartilage

chondronectin

adhesive glycosaminoglycan found in cartilage

collagenous fiber

structural protein that is commonly located in tendons and ligaments

compound gland

exocrine gland with branched ducts

connective tissue proper

includes all types of connective tissue except for bone, blood, and cartilage. Is divided into two subclasses: loose and dense connective tissue

connexon

proteinaceous channel that aids in the intercellular transport of nutrients

cuboidal cell

cube-shaped cells with centrally located nuclei

cuboidal epithelium

epithelium composed of cuboidal cells

cutaneous membrane

also known as the integument. Outer layer (epidermis) is composed of keratinized stratified squamous epithelium. Helps to waterproof and prevent dehydration of the body. Inner layer (dermis) is composed of dense irregular connective tissue, as well as collagenous and elastic fibers. Gives reinforcement and flexibility.

dendrite

receptive sites of the nerve cell; they extend from the cell body, giving the cell a starlike shape; receive stimuli and convey them as nerve impulses to the cell body

dense connective tissue

highly fibrous connective tissue with little vascularization. Functions to reinforce and bind body structures. Dense regular and dense irregular.

dense irregular connective tissue

collagen-based fibrous connective tissue that is found in the dermis, spleen, and liver. Has thicker bundles of fiber than dense regular connective tissue and is designed to withstand tension from multiple direction.

dense regular connective tissue

tightly bound, minimally vascularized fibrous connective tissue found in ligaments, tendons, and fascia. In ligaments it binds joints, whereas in tendons it binds muscle to bone. In fascia, it helps support surrounding tissues.

desmosome

type of intercellular attachment found in epithelial tissue. The bond is formed from the interlocking of filaments that connect the plasma membranes of adjacent cells.

diapedesis

process by which white blood cells leave capillaries and enter tissue by squeezing through the tiny spaces between the capillary cells

duct

tubelike channel that provides an exit route for secretory or excretory products

effusion

excess fluid that has escaped into a body cavity to the detriment of normal body function

elastic cartilage

also called yellow cartilage; similar to hyaline cartilage, except that it is more opaque and contains many elastic fibers. It is found in the external ear and in the epiglottis.

elastic connective tissue

connective tissue composed of large numbers of elastic fibers; found in tissues that expand and contract, such as the lungs and vocal cords

elastic fiber

fibers composed of elastin. Form a delicate mesh in tissues

endocrine gland

glands or cells that release their regulatory products (hormones) directly into the bloodstream. Control most metabolic functions. Ex) pituitary, parathyroid, pancreas

endocrine system

system of glands that controls and regulates body functions through the internal secretion of hormones. Hormones are released directly into the bloodstream, which allows them to exert their actions on target cells throughout the body

endothelium

derived from mesothelium, the endothelium is composed of simple squamous epithelium. It lines the heart, blood vessels, and serous cavities of the body.

epidermis

composed of keratinized stratified squamous epithelium, outermost layer of skin

epithelialization

rapid division of epithelial cells around a wound edge. Attempts to cover the opening of a wound. This process is assisted by the contraction of collagen fibers, which brings the edges of the epithelial layer into close opposition

erythrocyte

also called red blood cells or red corpuscles, these cells are anucleated and biconcave in shape. Are responsible for carrying oxygen from the lungs to tissues. Are formed in the red bone marrow of adults and in the liver, spleen, and marrow of a fetus. Also manufactured in the spleens of anemic and ill adults.

excretory duct

ducts that transport waste products or secretions out of an organ or gland

exocrine gland

glands that release their secretions through ducts that lead directly to the location intended to be controlled. ex) some sweat glands and salivary glands

extracellular fiber

fibers of connective tissue located outside cells that perform a variety of functions depending on the degree of their elasticity or concentration

extracellular matrix

nonliving substance found between cells that provides support and nourishment

exudate

accumulation of fluid, pus, or serum in a cavity or tissue. Fluid or serum has often leaked through vessel walls or capillaries into the adjoining space.

fascia

arrangement of dense regular connective tissue that lies over muscle. This layer helps to support, separate, and connect muscles to other structures.

fibrin

protein created when thrombin acts on fibrinogen. Is essential to the coagulation of blood. It forms a lattice of interwoven fibers around blood cells and platelets that solidify to form a blood clot

fibrinogen

protein formed in the liver and released into the bloodstream, especially in the presence of inflammatory processes. When acted on by thrombin, forms fibrin, which creates meshwork of a blood clot

fibroblast

fixed cell involved in the development of connective tissue. Can differentiate into chondroblasts and osteoblasts to create substances specific to their cell type

fibrous adhesion

fibrous connections that are generated during the healing process; often seen in the abdominal and thoracic cavities after surgical procedures

first-intention healing

healing that occurs in tissues in which the wound edges are held in close apposition to one another, as in the case of a sutured wound. Little to no granulation tissue is formed. Generally minimal scarring.

fixed cell

one of the two subdivisions of connective tissue cells. Fixed cells are stationary within the connective tissue and perform functions such as matrix production and regulation

gap junction

proteinaceous pores that exist in the intestinal epithelial cells of most animals. These pores allow the passage of nutrients, as well as providing a channel for intercellular communication.

glandular epithelium

epithelial tissue composed of one cell (goblet cell) or groups of cells that produce and secrete substances into the lumen

glycosaminoglycan (GAGs)

carbohydrates composed of amino sugars, which are found in proteoglycans

goblet cell

type of cell, located in the respiratory and intestinal tracts, that secrete mucus

granulation tissue

new vascular and cellular tissue formed during the restoration of wounded tissue. It mostly consists of connective tissue and new blood vessels.

gristle

lay term for cartilage

ground substance

shapeless, viscous matrix present in connective tissue in which cells receive nutrients and void waste products. It also helps to protect the body from infectious agents by acting as a barrier

Haversian canal

central canal that runs the length of a Haversian system. Contains the blood vessels, lymph vessels, and nerves that supply and nourish the osteocytes

hemidesmosome

half-units of desmosomes

hemothorax

blood present in the pleural cavity as a result of a condition such as pneumonia, cancerous tumors, or trauma

heparin

polysaccharide manufactured by mast cells that acts as an anticoagulant to help continue the increased blood flow during the inflammatory response

hibernating gland

alternate nomenclature for brown adipose tissue, owing to its glandular appearance and its vital role in providing body heat to an animal during hibernation

histamine

produced by mast cells from histidine during tissue injury, this biochemical increases blood flow and heart rate during the inflammatory response

histiocyte

macrophages located in loose connective tissue

histology

microscopic study of the structure of tissues and organs; microanatomy

holocrine gland

gland whose granular secretions contain not only the secretory product but also the cells themselves. The cells are destroyed in the process of secretion. ex) sebaceous gland

hormone

chemical messengers of the body that are produced and excreted by endocrine glands for the purpose of regulating specific organs or cells

hyaline cartilage

bluish, translucent cartilage present in the costal cartilage, trachea, and embryonic skeleton. Is composed of densely packed collagen fibers and is covered by the perichondrium, except when present as articular cartilage in joints

hyaluronic acid

small protein containing no sulfate that acts as an intercellular material present in the zonula adherens. It is important in the formation of tight junctions

hyaluronidase

enzyme contained within white blood cells or infectious bacteria that hydrolyzes hyaluronic acid

immunoglobulin

created by B lymphocytes; also called antibodies; these protein-based molecules are produced by exposure to an infectious agent's antigen. In future encounters with the same antigen, the antibodies will identify and fight it.

inflammatory process

series of cellular and metabolic events that take place primarily in connective tissue as the result of injury or loss of tissue. Acts to isolate and destroy infectious agents, as well as to prepare the tissue for healing

junctional complex

point at which epithelial cells join to one another in very close proximity

keratin

tough, waterproof protein that makes up scales, the outer sheaths of beaks and claws, and feathers; a major component of the epidermis, nails, hair, horns, and hooves

keratinized stratified squamous epithelium

epithelial classification of the epidermis. Highly regenerative and waterproof, thereby helping the body to retain moisture and thermoregulate

Kupffer cell

macrophages present in the liver. Fifty percent of macrophages are these.

lacunae

small cavities within the matrix of some connective tissues, such as cartilage and bone, within which cells (chondrocytes and osteocytes) are contained

lamina propria

areolar connective tissue located in the mucous membranes

leukocyte

also called white blood cells, come in many different varieties, including basophils, eosinophils, neutrophils, lymphocytes, and monocytes. May be granulated or nongranulated and are capable of amoeboid motion. Main function is body defense

loose connective tissue

subclass of connective tissue proper, is a vascularized type of connective tissue whose general function is to support the structures it surrounds. Types of loose connective tissue include areolar, adipose, and reticular connective tissues

lumen

opening in the middle of the intestinal tract or any hollow organ

macrophage

phagocytic cells that can engulf relatively large cells or bits of debris. May be fixed in place, or they may travel around in the tissues. Mature ones may become more mobile during times of infection and inflammation

mast cell

transient cell of connective tissue containing heparin and histamine used in the inflammatory response. Recognize foreign invaders and release granules of histamine and heparin to increase blood flow. Resemble basophils, but they do not circulate in blood

merocrine gland

gland whose secretions contain none of its cells, thus leaving the gland cells intact. ex) salivary and sweat glands

mesoderm

middle layer of fetal body tissues. Located between the outer layer (ectoderm) and inner layer (endoderm), it gives rise to all connective and muscle tissues

mesothelium

layer of cells that lines the body cavities of the fetus and that covers the serous membranes in adult animals

microbe

microscopic organism that may or may not cause disease

microglial cell

macrophages located in brain tissue

mixed exocrine gland

exocrine glands, such as salivary glands, that can produce both mucous and serous secretions

mucin

main constituent of mucus, produced by goblet cells in the respiratory and intestinal tracts. Composed of proteoglycans.

mucous membrane

mucus-producing layer of stratified squamous or columnar epithelium found over the lamina propria. It is present in organs that have contact with the outside of the body. Mucus production in them is commonly found in the digestive, respiratory, and reproductive tracts, with the exception only of the urinary tract. The mucus secreted in them helps to fight infection because it is loaded with antibodies. Also helps absorb nutrients and lubricate surfaces.

mucous secretin

viscous secretions composed mostly of glycoproteins