Tissues

8. Tissues - groups of similar cells that perform similar functions 9. Histology - the study of tissues

Four Types of Tissues

11. Epithelial Tissue – covers the body and organs

Epithelial Characteristics a. Cells fit close together b. Usually avascular (no blood supply) c. High regeneration rate d. Attach to a basement membrane

Classification Number of layers Shape

Number of layers Simple – one layer Stratified – two or more layers

Simple or Stratified?

Simple or Stratified?

Shape Squamous – flattened, scale-like Cuboidal – box-like Columnar – tall, column-like Nucleus conforms to the shape of the cell

Squamous, Cuboidal, or Columnar?

Squamous, Cuboidal, or Columnar?

Squamous, Cuboidal, or Columnar?

Simple Epithelial C. Absorption, secretion, filtration – not protection

a. Simple Squamous Epithelium – diffuse and filter Found –air sacs in lungs, blood capillaries

b. Simple Cuboidal Epithelium – secrete and absorb Found –kidney tubules, ovaries, ducts of glands

c. Simple Columnar Epithelium – absorb and secrete mucus – some are ciliated Found – lines stomach and intestines

d. Pseudostratified Columnar Epithelium – secrete mucus – nuclei are uneven so looks like many layers Found – lines trachea

Draw picture in your notes

Stratified Epithelial D. mostly protection – can be more than one shape but is named from top layer

a. Stratified Squamous Epithelium – protect areas from wear and tear Found – skin, esophagus, mouth

b. Stratified Cuboidal Epithelium – rare Found – sweat and mammary glands

c. Stratified Columnar Epithelium – rare Found – male urethra, pharynx

d. Transitional Epithelium – stretchy, easily expands and contracts Found – bladder, urinary track

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Now with real slides

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Four Types of Tissues

12. Connective tissue - joins or connects body structures together, supports, protects, insulates, and transports

Connective Characteristics a. Most abundant tissue b. regenerates at varying rates c. made of mostly nonliving extra-cellular matrix d. relatively few cells and widely separated from each other

Classification Areolar Fibrous Adipose Cartilage Osseous (bone) Blood

C. Areolar tissue – loose, space filling tissue, supports organs and skin, holds and conveys tissue fluids a. Found – surrounds organs and capillaries

D. Fibrous tissue – dense, attaches muscles to bones or muscles, attaches bone to bone, withstands tension a. Found – tendons and most ligaments

E. Adipose tissue – stores energy (fat), insulates, supports & protects organs a. Found – under skin, around kidneys and heart, abdomen and hips

Nucleus Giant vacuole of fat

Cartilage Tough but flexible No nerves or veins Slow regeneration Hyaline Elastic Fibrocartilage

b. Hyaline Cartilage – most common type, resists compressive stress, supports and reinforces Found – ends of long bones, ribs, nose, trachea, and larynx

c. Elastic Cartilage – more flexibility but still maintains shape Found – ear, epiglottis Elastic fibers

d. Fibrocartilage – thick fibers, absorb compressive shock Found – vertebrae, knee joint

G. Osseous tissue – hardest connective tissue, supports, protects, highly vascular, stores minerals Found – bones

H. Blood tissue – fluid, transports nutrients and wastes Found – inside blood vessels

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Four Types of Tissues

13. Muscle tissue - contracts to allow body movement

Muscle Characteristics a. Very vascular b. Large amounts of energy c. Lots of mitochondria d. Cells are usually long and slender

Classification Skeletal Smooth Cardiac

Skeletal muscle – move your skeleton a. Voluntary muscle – we consciously control them b. Striated – has narrow bands c. Each cell has many nuclei

Skeletal Muscle

D. Smooth muscle – found in internal organs a. Involuntary muscle – don’t consciously control them b. Not striated – no narrow bands c. Each cell only has one nucleus

Smooth Muscle

E. Cardiac Muscle – found only in the heart a. Involuntary muscle b. Striated and branched 7. Each cell has only one nucleus

help send nerve signals across a constantly beating heart Cardiac Muscle Intercalated disks help send nerve signals across a constantly beating heart

Muscle Tissue

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14. Nervous tissue - carries information throughout the body

Characteristics a. Neurons - branching nerve cells b. Found – brain, spinal cord, and nerves throughout body c. Almost no regeneration

Structure

15. Tissue Repair A. Inflammation – injured cells release chemicals, blood vessels dilate, clot forms, scab Leads to… Regeneration or Fibrosis

Tissue Repair a. Regeneration - replacing destroyed tissue with the same kind of tissue

Tissue Repair b. Fibrosis - replace damaged tissue with fibrous connective tissue (scar)

Regeneration depends on tissue type Cartilage Skeletal muscle Skin Bone Nervous Tissue Fibrous tissue Cardiac muscle Smooth muscle Blood

What tissue regenerates well? a. Regenerates Well: skin, bone, stomach, blood b. Regenerates Poorly: cartilage, fibrous tissue, skeletal muscle c. No regeneration: nervous, cardiac

Conditions affecting Repair a. Blood supply-needs oxygen and nutrients b. Age- heal faster when you’re younger c. Nutrition-needed vitamins and minerals Vitamins: A=healthy skin C=immune system D=bone E=healing K=blood clotting

16. Issues with Tissues A. Cancer – abnormal growth of cells a. Benign (kindly) – grow slowly, push around cells, localized b. Malignant (bad) – grow quickly, invade other cells, and travel

Carcinogens (cancer causers) include: radiation trauma certain viral infections chemicals (tobacco tars) Cancer can arise from any tissue, but the most common are found in skin, lungs, colon, breast, and prostate Treatments: cut, burn, poison

Colon Polyp

Oral cancer