Tissues of the Body

From Cells to Organ Systems

Cells combine to form tissues, and tissues combine to form organs

Tissues are groups of cells closely associated that have a similar structure & perform a related functionCells combine to form 4 primary tissues *Epithelial *Nervous

*Connective *Muscle

Human Body Tissues

Epithelial Tissue Locations:◦ Covers the body◦ Lines the cavities, tubes, ducts and blood

vessels inside the body◦Covers the organs inside body cavities

Epithelial Tissue Functions:◦ Protection from physical & chemical injury,◦ Protection against microbial invasion,◦ Contains receptors which respond to stimuli,◦ Filters, secretes & reabsorbs materials and◦ Secretes serous fluids to lubricate structures.

Epithelial Tissue

Two types: o membranous epithelia form the coverings or

linings of organso glandular epithelia form exocrine and

endocrine glands Sheets of cells with specialized contacts & cell

junctionso Basal lamina: protein scaffolding secreted by

epithelial cellso Basement membrane: reticular fibers

(crossed collagen network) that supports epithelium--really associated connective tissue

Epithelial Tissue

Connective tissue support Nutrients from capillaries in underlying connective

tissue Nerves pass through Easily regenerates Different cell shapes & arrangements

Epithelial Tissue

Simple: just one layer or cell shape

Stratified: multiple layers and cell shapes

Classes of Epithelia

TYPE CELL SHAPE EXAMPLE Squamous Squashed

Cuboidal Cubed

Columnar Columns

Pseudo-stratified Flat cells give rise to columns

Endothelium (lines blood vessels), mesothelium (serous lining of celom)

Walls of glands

Lining of gut tube; sometimes with cilia like lining of uterine tube

With cilia in respiratory tubes to move mucous & particles out of the lungs

Simple Epithelia

Simple Squamouso One cell thicko Forms solid layer of cells

which line blood vessels, body cavities & cover organs in body cavities

o Lubrication Stratified Squamous

o Multiple layerso Forms epidermis (Skin)

lining of the moutho Lubrication & protection

Squamous Epithelia

Simple Cuboidal o One cell thick, roughly cube

shaped o Lines ovaries, kidneys, thyroid

glands, where secretion & absorption take place

Cuboidal Epithelia

Stratified Cuboidal o In multiple layers w/one layer

attached to basement membrane & one w/free edge

o Mammary & sweat glandso Secretion, absorption &

protection

Simple Columnar o One cell thick column

shaped (long & narrow) o Line digestive tract where

re-absorption & secretion occurs.

Columnar Epithelia

Stratified Columnar o Stacked nucleus on top of

nucleuso Lines vas deferans, male

urethrao Gives support and some

movement.

Pseudostratifiedo gives the appearance of

more than one layer of columnar epithelial cells

o Every cell is attached to the basement membrane

o Lines the trachea, fallopian tubes

o movement

Columnar Epithelia

Transitional EpitheliaTransitional

o Several layers of epithelial cellso Forms tissue that must stretch like the

bladdero Stretches, protects against seepage

Glandularo A gland consists of one or more cells

that make and secrete a particular product.

o Endocrine: secretions diffuse directly into the blood vessels. Ex.– thyroid, adrenals, pituitary

o Exocrine: secretions empty through the ducts to the epithelial surface. Ex.- sweat, oil

Glandular Epithelia

Types of Epithelium

1

54

732

6

Muscle Tissue:o Associated with the bones of the

skeleton, the heart and in the walls of the hollow organs of the body.

Muscle Tissue Functions:o Movement & Locomotiono Maintains postureo Produces heato Facial expressionso Pumps bloodo Peristalsis

Muscle Tissue

Consists of specialized cells that contract when stimulated

The body has three types of muscle tissue:o Skeletalo Cardiaco Smooth muscle

Muscle Tissue

Cardiac (involuntary) HEARTSmooth (involuntary) ORGANSSkeletal (voluntary) BONES

Smooth Muscle

Cardiac Muscle

Skeletal Muscle

Muscle Tissue

Connective TissueConnective tissue location:

o Most abundant & widely distributed tissueo Connective tissue has non-living extra-

cellular material (matrix between its cellsConnective Tissue Functions:

o Connects, binds and supports structures,o Tendons, ligaments, etc.o Protects & cushions organs and tissues,o Insulates (fat) ando Transports substances (blood).

Major classes: o Boneo Cartilageo Looseo Denseo Blood

All connective tissues consist of two basic components:o Living cells o Extracellular matrix

Connective Tissue

Fiberso Collagen gives structureo Reticular fibers (crossed

collagen) gives ordero Elastin gives elasticity

Ground substanceo Jelly-like material made of

sugar-protein molecules (proteoglycans)

o Allows connective tissue to retain water and serve as support and protection of organs

Extracellular Matrix

Type: Loose, adipose

Type: Loose, areolar

Loose Fibrous

Adipose

Areolar

o Stores energy (fat) & insulateso Mostly under the skin

o Wraps the organso Cushions & protects

Contains elastinNourishes & stretches

o Provides blood vessels to skino Fills muscle gaps

Dense Fibrouso Collagen is the main

matrix elemento Thick fibers running in

many planes• Dermis, fibrous capsules

around organso Aligned parallel fibers

that resists tension• Tendon, ligaments

Dense Fibrous

Perform specific functions essential to homeostasis

The body contains three types of specialized connective tissue:o Boneo Cartilageo Blood

Specialized connective tissue

Bone o Consists of bone cells

(osteocytes) and a calcified cartilage matrix

o Two types of bone tissue exist: spongy and compact

Osseous

Tree ring-like appearance Supports & protects Mineral storage Fat storage Blood cell production

Supports while providing flexibility

Hyaline cartilage absorbs compression between bones in joints (bone ends)o Most abundant type of

cartilage found in the body

Fibrocartilage forms cushion like disks between the vertebra

The ears and nose are more flexible and are elastic cartilage

Cartilage

Bloodo Red & white blood cellso Plateletso Plasmao Regulates temperatureo Transportation system

Blood

Nervous Tissue:◦ Main component of the nervous

system ie., brain, spinal cord & nerves.Nervous Tissue Functions:

◦ Regulates & controls body functions◦ Generates & transmits nerve impulses◦ Supports, insulates and protects

impulse generating neurons.

Nervous Tissue

Contains specialized cells that conduct impulses

Conducting cells, called neurons, transmit impulses from one region of the body to another.

Nonconducting cells, neuroglia, are a type of nervous system connective tissue.

Nervous Tissue

Stomach wall tissue

Skin