1Chapter 5 Key Terms

TendonOsteocytes

ErythrocytesLigamentsAxon

DendritesLeukocytesPeritoneumVisceralParietalPleura

PericardiumAxon

AdiposeElastic CartilageHyaline Cartilage

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ANATOMY & PHYSIOLOGYCHAPTER 5: TISSUES

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Tissues

A group of specialized cells that work together to perform a specific function

The basic unit of a tissue is a cell The tissue is classified based on how the cells are

arranged Histology – study of tissues 4 types of tissues:

Epithelial, connective, muscle, nervous

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Epithelial Tissue

CharacteristicsCells are tightly packed togetherLacks a rich blood supplyReproduce rapidlyGood nerve supply

Epithelial tissue covers a surface orlines a cavity

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Epithelial Tissue

Four functions:

1. Protects underlying tissues

2. Absorbs

3. Secretes

4. Excretes Anchored to the basement membrane and cells

around it Named according to shape and number of layers

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Epithelial Tissue

Named according to shapeSquamous: protectionCuboidal: protection and secretionColumnar: secretion and absorption

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Epithelial Tissue

Named according to layersSimple: 1 cell layerStratified: several layersPseudostratified: appears to be several layers, but is

notTransitional: several layers of easily stretched cells

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Epithelial Tissue

Can also be named based on function Mucous membrane

Lines all cavities that open to the outside of the body (digestive, respiratory, urinary, reproductive tracts)

Often ciliatedProtects, absorbs nutrients, and secretes mucus,

enzymes and bile salts

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Epithelial Tissue

Glandular Epithelium Exocrine Glands

Have excretory ducts that lead from the gland to the surface of the skin

Simple Exocrine Glands: single unbranching ductsEx. Sweat glands, sebaceous glands

Compound Exocrine Glands: branching ductsEx. Salivary glands

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Epithelial Tissue

Endocrine GlandsDuctless glands that secrete hormonesEx. Thyroid gland, pituitary gland

Goblet CellsUnicellular gland that secretes mucusScattered throughout the epithelial cells

that make up mucous membrane

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Epithelial Tissue

EndotheliumSpecial epithelium that mainly lines the circulatory

systemUsually a simple squamous arrangement of cellsCapillaries consist of 1 layer of endothelium

EndocardiumEndothelium that lines the inner parts of the heart

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Epithelial Tissue

Mesothelium (AKA Serous Tissue)Lines the large cavities of the body that do not open to the

outsideSimple squamous layer overlying connective tissue

Pleura: serous membrane that lines the thoracic cavity Pericardium: serous membrane that covers the heart Peritoneum: serous membrane lining abdominal cavity This type of tissue helps reduce friction between organs

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Connective Tissue

Allows movement and provides support for other types of tissues

Has abundance of extracellular fluid called matrix Contains collagen and elastin fibers embedded in

matrix 3 types:

Loose connectiveDense connectiveSpecialized connective

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Loose Connective Tissue

Fibers are not tightly woven among themselves 3 types of loose connective tissue:

AreolarAdiposeReticular

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Loose Connective Tissue

AreolarMost widely distributed of the loose connective tissueEasily stretches without tearing3 main types of cells among its fibers

Fibroblasts: form fibrilsHistiocytes: also called macrophagesMast cells: produce heparin and

histamine

Basic support tissue around organs, muscles, nerves,

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Loose Connective Tissue

AdiposeLoaded with fat cellsLarge vacuole that contains stored fatNuclei and cytoplasm are pushed up against cell

membraneAct as protective packing around and between

organs, muscle fibers, and nervesPoor conductors

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Dense Connective Tissue

Dense Regular Connective tissueConsists of many closely packed

collagenous fibers, a fine network of elastin fibers, and some cells

(mainly fibroblasts)Lack good blood supply

Ligaments: attach bone to bone Tendons: attach muscle to bone Aponeuroses: wide, flat tendons

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Dense Connective Tissue

Dense Irregular Connective TissueCollagen fibers are thicker and more randomly

organizedAllows tissue to sustain tension

exerted from many directions

Dermis layer of the skin Fascia: covering of a muscle

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Specialized Connective Tissue

CartilageCells are called chondrocytes (chondro = cartilage)Found in cavities called lacunaeVarious amounts of collagen and elastin fibers

embedded in matrix cause cartilage to be either flexible or very rigid

3 types of cartilage found in the body

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Specialized Connective Tissue

Hyaline CartilageHas very fine collagen fibersFound at ends of long bonesFetal skeletal is entirely hyaline cartilage for first

several monthsOssification (process of bone replacing cartilage)

occurs over the next several months until baby is born

Found in trachea, bronchi, septum in nose, costal cartilage that connects ribs to sternum

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Specialized Connective Tissue

FibrocartilageDense and resistant to

much stretching (very tough)

Contains many collagenous fibers

Functions as a shock absorber

Found in intervertebral disks and knees

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Specialize Connective Tissue

Elastic CartilageAbundance of elastin

fibersThese fibers allow this

cartilage to be easily stretched

Framework for external ear and parts of larynx

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Specialized Connective Tissue

BoneMost rigid connective tissueMade up of compact bone

and cancellous/spongy bone

Matrix has abundance of mineral salts

Good blood supply Osteocytes

Bone cells

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Special Connective Tissue

Blood and hematopoietic tissueUnique in that it is composed

of a fluid portion and the cells Erythrocytes

Red blood cells Leukocytes

White blood cells Transports substances to body

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Muscle Tissue

Its characteristic ability is its ability to contract Often referred to as a muscle fiber because they

are very long and cylindrical Smooth Muscle

Cells are spindle shapedUsually involuntary/controlled by autonomic nervous

systemLack striations: work slowly and rhythmicallyPeristalsis: movement of food down esophagus

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Muscle Tissue

Skeletal/striated muscleVoluntary muscle (controlled by conscious effort)Cells are long and cylindricalAllows you to react quickly, but also fatigue quicklyStriations are caused by alternating light and dark

bands within the muscleLight bands = actinDark bands = myosin

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Muscle Tissue

Cardiac MuscleOnly found in the heart InvoluntaryConnected to each other by intercalated disksThe branches of this tissue allow for simultaneous

pumping of the heartPumps blood throughout the body

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Nervous Tissue

NeuronNerve cell (sometimes called nerve fibers because of

length)Long cells that carry electrical impulse along its axonLive a long time because they are amitoticPurposes are to detect environment, coordinate

activities, thinking, memory, emotions, logicMakes up brain, spinal cord, and nerves of the body

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Nervous Tissue

Cell body: contains the nucleus Dendrite: connect to other

cells Receive stimuli from other

cells and conduct them to body Axon: long extension of cell

body Axon Ending: Connects to

other cells