Chapter #4 tissue: the living cell

"Cyte" cell (grown adults)

mature form;maintain matrix chondrocytes: in cartilage Osteocytes: in bone

glandular epithelia

-inner lining -secretory tissue in glands

Picture of Smooth, cardic, and skeletal muscle

(a) Skeletal muscle cells have prominent striation and nuclei on their periphery. (b) Smooth muscle cells have a single nucleus and no visible striations. (c) Cardiac muscle cells appear striated and have a single nucleus.

Adipose tissue

(loose connective tissue) consists mostly of fat storage cells, with little extracellular matrix. -A large number of capillaries allow rapid storage and mobilization of lipid molecules. -White fat contributes mostly to lipid storage and can serve as insulation from cold temperatures and mechanical injuries.

areolar tissue

(loose connective tissue) a type of connective tissue proper that shows little specialization with cells dispersed in the matrix

Pseudostratified

(pseudo- = "false") describes tissue with a single layer of irregularly shaped cells that give the appearance of more than one layer.

simple cuboidal epithelium

- nucleus of the box-like cells appears round and is generally located near the center of the cell -These epithelia are active in the secretion and absorptions of molecules. -Simple cuboidal epithelia are observed in the lining of the kidney tubules and in the ducts of glands.

fluid connective tissue

- in other words, lymph and blood, various specialized cells circulate in a watery fluid containing salts, nutrients, and dissolved proteins.

macrophage cell

- large cell derived from a monocyte, a type of blood cell, which enters the connective tissue matrix from the blood vessels. -essential component of the immune system, which is the body's defense against potential pathogens and degraded host cells.

What do the Merocrine and Apocrine glands have in common?

-Both merocrine and apocrine glands continue to produce and secrete their contents with little damage caused to the cell because the nucleus and golgi regions remain intact after secretion

Connective Tissue Proper

-Fibroblasts are present in all connective tissue proper. - Fibrocytes, adipocytes, and mesenchymal cells are fixed cells, which means they remain within the connective tissue. -cells that move in and out of the connective tissue in response to chemical signals. Macrophages, mast cells, lymphocytes, plasma cells, and phagocytic cells are found in connective tissue proper but are actually part of the immune system protecting the body

anchoring junction

-Help stabilize epithelial tissues -Anchoring junctions are common on the lateral and basal surfaces of cells where they provide strong and flexible connections. -There are three types of anchoring junctions: desmosomes, hemidesmosomes, and adherens.

mucous membrane

-a composite of connective and epithelial tissues. -Sometimes called mucosal -epithelial membranes line the body cavities and hollow passageways that open to the external environment, -include the digestive, respiratory, excretory, and reproductive tracts.

basal lamina (base surface)

-a mixture of glycoproteins and collagen, provides an attachment site for the epithelium separating it from underlying connective tissue. -attaches to a reticular lamina, which is secreted by the underlying connective tissue, forming a basement membrane that helps hold it all together

Epithelial tissue

-also referred to as epithelium -refers to the sheets of cells that cover exterior surfaces of the body, lines internal cavities and passageways, and forms certain glands. -lining of GI tract organs and other hollow organs, skin surface, epidermis

Pseudostratified columnar epithelium

-appears to be stratified but instead consists of a single layer of irregularly shaped and differently sized columnar cells. -nuclei of neighboring cells appear at different levels rather than clustered in the basal end. -gives the appearance of stratification; but cells are in contact with the basal lamina, -found in the respiratory tract, where some of these cells have cilia

connective tissue

-binds the cells and organs of the body together and functions in the protection, support, and integration of all parts of the body. -Largest tissue -fat and other soft padding tissue, bone, tendons, blood

Supportive connective tissue

-bone and cartilage—provide structure and strength to the body and protect soft tissues. -A few distinct cell types and densely packed fibers in a matrix characterize these tissues. -In bone, the matrix is rigid and described as calcified because of the deposited calcium salts.

Stratified cuboidal epithelium and stratified columnar epithelium:

-can also be found in certain glands and ducts -uncommon in the human body.

Adipocytes

-cells that store lipids as droplets that fill most of the cytoplasm. There are two basic types of adipocytes: -white and brown. brown- store lipids as many droplets, and have high metabolic activity. -white fat adipocytes store lipids as a single large drop and are metabolically less active.

Three main types of fibers are secreted by fibroblasts:

-collagen fibers, elastic fibers, and reticular fibers. -All of these fiber types are embedded in ground substance

Stratified squamous epithelium

-common type of stratified epithelium in the human body. -apical cells are squamous, whereas the basal layer contains either columnar or cuboidal cells. Ex. The lining of the mouth cavity is an example of an unkeratinized, stratified squamous epithelium.

epithelial membrane

-composed of epithelium attached to a layer of connective tissue. Ex. your skin

major functions of connective tissue

-connect tissues and organs -typically have in common three characteristic components: cells, large amounts of amorphous ground substance, and protein fibers.

Dense regular

-connective tissue fibers are parallel to each other, enhancing tensile strength and resistance to stretching in the direction of the fiber orientations.

Elastic cartilage

-contains elastic fibers as well as collagen and proteoglycans. -This tissue gives rigid support as well as elasticity. -The external ear contains elastic cartilage.

Dense connective tissue

-contains more collagen fibers than does loose connective tissue. As a consequence, it displays greater resistance to stretching. -There are two major categories of dense connective tissue: regular and irregular.

elastic fiber

-contains the protein elastin along with lesser amounts of other proteins and glycoproteins. -main property of elastin is that after being stretched or compressed, it will return to its original shape. -Elastic fibers are prominent in elastic tissues found in skin and the elastic ligaments of the vertebral column.

totipotent

-embryonic cells generated have the ability to differentiate into any type of cell in the body -each has the capacity to divide, differentiate, and develop into a new organism.

serous membrane

-epithelial membrane composed of mesodermally derived epithelium, called the mesothelium that is supported by connective tissue. - line the coelomic cavities: cavities that do not open to the outside, and they cover the organs located within those cavities.

endothelium

-epithelial tissue that lines vessels of the lymphatic and cardiovascular system, and it is made up of a single layer(simple) of squamous cells.

neuroglia

-essential role in supporting neurons and modulating their information propagation.

reticular fibers

-formed from the same protein subunits as collagen fibers however these fibers remain narrow and are arrayed in a branching network. -found throughout the body, most abundant in the reticular tissue of soft organs, such as liver and spleen, where they anchor and provide structural support to the parenchyma

connective tissue

-formed solely from connective tissue. -These membranes encapsulate organs, such as the kidneys, and line our movable joints.

gap junction

-forms an intercellular passageway between the membranes of adjacent cells to facilitate the movement of small molecules and ions between the cytoplasm of adjacent cells. - allow electrical and metabolic coupling of adjacent cells, which coordinates function in large groups of cells.

Loose Connective Tissue

-found between many organs where it acts both to absorb shock and bind tissues together. -It allows water, salts, and various nutrients to diffuse through to adjacent or imbedded cells and tissues.

parenchyma

-functional cells of a gland or organ, in contrast with the supportive or connective tissue of a gland or organ

goblet

-goblet cell is a mucous-secreting unicellular "gland" interspersed between the columnar epithelial cells of mucous membranes

squamous epithelium

-have the appearance of thin scales (fish scales) -tend to be flat, horizontal, and elliptical, mirroring the form of the cell.

Reticular tissue

-is a mesh-like, supportive framework for soft organs such as lymphatic tissue, the spleen, and the liver. -produce the reticular fibers that form the network onto which other cells attach. -It derives its name from the Latin reticulus, which means "little net."

tissue membrane

-is a thin layer or sheet of cells that covers the outside of the body (for example, skin), the organs (for example, pericardium), internal passageways that lead to the exterior of the body (for example, abdominal mesenteries), and the lining of the moveable joint cavities.

Nervous tissue

-is excitable, allowing the propagation of electrochemical signals in the form of nerve impulses that communicate between different regions of the body -Brain, spinal cord, nerves

Muscle tissue

-is excitable, responding to stimulation and contracting to provide movement. -occurs as three major types: skeletal muscle(voluntary), smooth muscle(involuntary), and cardiac muscle in the heart(involuntary).

Adherens

-junctions that use either cadherins or integrins depending on whether they are linking to other cells or matrix.

myelin

-layer of lipid inside some neuroglial cells that wraps around the axons of some neurons

fibrocyte

-less active form of fibroblast

Hemidesmosomes

-look like half a desmosome -link cells to the extracellular matrix Ex. The basal lamina. - they include the adhesion proteins called integrins

collagen fiber

-made from fibrous protein subunits linked together to form a long and straight fiber. -flexible, have great tensile strength, resist stretching, and give ligaments and tendons their resilience and strength. -these fibers hold connective tissues together, even during the movement of the body

stratified epithelium

-more than one layer of cells, -only the basal layer(bottom) of cells rests on the basal lamina. -protects against physical and chemical wear and tear

Connective tissue

-most abundant and widely distributed four main classes: -connective tissue proper -cartilage -bone(largest) -blood(most abundant)

fibroblast

-most abundant cell type in connective tissue -secretes protein fibers and matrix into the extracellular space

simple columnar epithelium

-nucleus of the tall column-like cells tends to be elongated and located in the basal end of the cells. -Like the cuboidal epithelia, this is active in the absorption and secretion of molecules. -forms the lining of some sections of the digestive system and parts of the female reproductive tract.

Desmosomes

-occur in patches on the membranes of cells. The patches are structural proteins on the inner surface of the cell's membrane. The adhesion molecule, cadherin, is embedded in these patches and projects through the cell membrane to link with the cadherin molecules of adjacent cells. - connections are especially important in holding cells together.

simple epithelium

-one layer of cells that rests on the basal lamina

Mucous

-produced by the epithelial exocrine glands, covers the epithelial layer.

neuron

-propagate information via electrochemical impulses, called action potentials, which are biochemically linked to the release of chemical signals.

Exocrine Glands (ducts)

-release their contents through a duct that leads to the epithelial surface. Ex. Mucous, sweat, saliva, and breast milk

Endocrine (ductless)

-secretions of endocrine glands are called hormones. Hormones are released into the interstitial fluid, diffused into the bloodstream, and delivered to targets. -part of a major regulatory system coordinating the regulation and integration of body responses. Ex. anterior pituitary, thymus, adrenal cortex, and gonads.

tight junction

-separates the cells into apical and basal compartments.

Glands are also named after the products they produce

-serous gland produces watery, blood-plasma-like secretions rich in enzymes such as alpha amylase -mucous gland releases watery to viscous products rich in the glycoprotein mucin. -Both serous and mucous glands are common in the salivary glands of the mouth. -Mixed exocrine glands contain both serous and mucous glands and release both types of secretions.

mesothelium

-simple squamous epithelium that forms the surface layer of the serous membrane that lines body cavities and internal organs -Mesothelial cells are squamous epithelial cells that secrete a fluid that lubricates the mesothelium.

lacunae (singular = lacuna)

-small spaces in bone or cartilage tissue that cells(chondrocytes) occupy

transitional epithelium

-stratified epithelium -It is found only in the urinary system, specifically the ureters and urinary bladder. -characterized by an apical layer of cells that change shape in response to the presence of urine

gland

-structure made up of one or more cells modified to synthesize and secrete chemical substances. -most glands consist of groups of epithelial cells.

dense irregular

-the direction of fibers is random -this arrangement gives the tissue greater strength in all directions and less strength in one particular direction.

Hyaline cartilage

-the most common type of cartilage in the body, consists of short and dispersed collagen fibers and contains large amounts of proteoglycans. -strong and flexible, -found in the rib cage and nose and covers bones where they meet to form moveable joints. -smooth

Fibrocartilage

-tough, because it has thick bundles of collagen fibers dispersed through its matrix. -examples of fibrocartilage: knee, jaw joints, and intervertebral discs

synovial membrane

-type of connective tissue membrane that lines the cavity of a freely movable joint. -For example, synovial membranes surround the joints of the shoulder, elbow, and knee. -prevents friction

smooth muscle

-under involuntary control -moves internal organs -cells contain a single nucleus -are spindle-shaped, and do not appear striated; each cell is a fiber

lamina propria

-underlying connective tissue, meaning literally "own layer", helps support the fragile epithelial layer.

ground substance

-unstructured material that fills space between cells -medium through which solutes diffuse between blood capillaries and cells Components: -interstitial fluid -cell adhesion proteins (glue for attachment) -Proteoglycans

skeletal muscle

-usually attached to bone -under voluntary control -each cell is a fiber that is multinucleated and striated

matrix

-usually includes a large amount of extracellular material produced by the connective tissue cells that are embedded within it. -plays a major role in the functioning of this tissue. -major component of the matrix is a ground substance often crisscrossed by protein fibers.

5 characteristics of epithelial tissue

1. Polarity 2. specialized contacts 3. supported by connective tissue 4. Avascular, but innervated(Nerves) 5. Can regenerate(best)

Steps in tissue repair

1. inflammation sets stage 2. organization restores blood supply 3. regeneration and fibrosis

cell junction

Adjoining cells form a specialized intercellular connection

Characteristics of epithelial tissue: Polarity

Cells have polarity -Apical surface (upper face,top) exposed to exterior or cavity(cilia) -Basal surface(lower, base bottom, attached,)

Proteoglycans

Competent of ground substance: -protien core+large polysaccharide(chorndroitin sulfate and hyaluronic acid) -trap water in varying amounts, affecting viscosity of ground substance

Embryonic Origin of Tissues

Each germ layer is identified by its relative position: --ectoderm (ecto- = "outer") -mesoderm (meso- = "middle"), -endoderm (endo- = "inner"). -the types of tissues and organs associated with the each of the three germ layers. (epithelial tissue originates in all three layers, whereas nervous tissue derives primarily from the ectoderm and muscle tissue from mesoderm.)

Classification of Epithelial Tissues

Epithelial tissues are classified according to the shape of the cells and number of the cell layers formed: - squamous (flattened and thin), - cuboidal (boxy, as wide as it is tall), - columnar (rectangular, taller than it is wide).

histology

Study of tissues

cutaneous membrane

The skin is an epithelial membrane also called this -It is a stratified squamous epithelial membrane resting on top of connective tissue.

tissue

Used to describe a group of cells found together in the body that perform common or related function

necrosis

accidental death of cells and tissues

striation

alignment of parallel actin and myosin filaments which form a banded pattern

clotting

also called coagulation; complex process by which blood components form a plug to stop bleeding

What has virtually no functional regenerative capacity?

cardio muscle and nervous system of brain and spinal cord if these are damaged they are hard to regenerate on there own.

chondrocytes

cells of the cartilage

histamine

chemical compound released by mast cells in response to injury that causes vasodilation and endothelium permeability

primary union

condition of a wound where the wound edges are close enough to be brought together and fastened if necessary, allowing quicker and more thorough healing

what are two basic types of tissue membranes?

connective tissue and epithelial membranes

cardiac muscle

heart muscle -under involuntary control -composed of striated cells that attach to form fibers, each cell contains a single nucleus, contracts autonomously

what are the three main types of cartilage tissue?

hyaline cartilage, fibrocartilage, and elastic cartilage

Blast cell (baby)

immature form, mitotically active, secrete ground substances and fiber: -fibroblasts: in connective tissue proper, like spiderman, web formation of clots, babies of clotting cell -chondroblasts: in cartilage -osteoblasts: in bone -Hematopoitic stem cells in bone marrow

Connective tissue proper

loose connective tissue and dense connective tissue -Both tissues have a variety of cell types and protein fibers suspended in a viscous ground substance. -Dense connective tissue is reinforced by bundles of fibers that provide tensile strength, elasticity, and protection. -loose connective tissue, the fibers are loosely organized, leaving large spaces in between.

atrophy

loss of mass and function

myocyte

muscle cells

oligodendrocyte

neuroglial cell that produces myelin in the brain

Schwann cell

neuroglial cell that produces myelin in the peripheral nervous system

wound contraction

process whereby the borders of a wound are physically drawn together

apoptosis

programmed cell death

inflammation

response of tissue to injury

mucous connective tissue ( or Wharton's jelly)

specialized loose connective tissue present in the umbilical cord

astrocyte

star-shaped cell in the central nervous system that regulates ions and uptake and/or breakdown of some neurotransmitters -contributes to the formation of the blood-brain barrier

Glandular Epithelium

two types: -endocrine gland, a ductless gland that releases secretions directly into surrounding tissues and fluids (endo- = "inside") -exocrine gland whose secretions leave through a duct that opens directly, or indirectly, to the external environment (exo- = "outside").

mesenchyme, mesenchymal cell

types of Embryonic Connective: embryonic tissue from which connective tissue cells derive mesenchymal cell: adult stem cell from which most connective tissue cells are derived

vasodilation

widening of blood vessels

secondary union

wound healing facilitated by wound contraction