histology

Introduction to Histology

• Four basic tissue types:Epithelial connective muscle nervous

• All animals are composed of ONLY these four tissue types

• Tissue types are organized to form organs, which form the functional systems of the body

Epithelial tissueEpithelial tissue

• Function: covers the internal and Function: covers the internal and external surfaces of the bodyexternal surfaces of the body

• Four types: Squamous, cuboidal, Four types: Squamous, cuboidal, columnar, and transitionalcolumnar, and transitional

• Organized in layers: simple or stratifiedOrganized in layers: simple or stratified

Examples: Epithelial

• Transitional Transitional epithelial: found in epithelial: found in the bladderthe bladder

• Stretches as the Stretches as the bladder becomes bladder becomes full full

p. 158 F draw above

Examples: Epithelial

• Simple squamous: Simple squamous: lines blood vessels lines blood vessels and lungsand lungs

• Allows for Allows for increased blood increased blood flow and increased flow and increased oxygen diffusionoxygen diffusion

p. 157 A

Examples: Epithelial

• Stratified squamous: lines the mouth, esophagus, cervix and skin

• Several layers offers protection to outer layers and membranes of body.

p. 157 B

Examples: Epithelial

• Simple columnar: digestive tracts

• Cells mixed with goblet cells that secrete mucous to aid in digestion

p. 158 D

Example Location Shape (form) Function

Transitional epithelium

Bladder Layer with no specific shape, Cells can stretch

Allow bladder to stretch as it fills

Simple squamous

Lungs, blood vessels

Flat and thin layer Increase flow and absorption rate through tubes

Stratified squamous

Skin, esophagus, mouth cervix

Several layers of thin flat cells

Provide protection from abrasions

Simple columnar

Digestive tract One cell layer of rectangular cells mixed with goblet (mucous –producing) cells

Aid in digestion with mucous production

Connective

• Function: Bind and support other Function: Bind and support other tissuestissues

• Several types:Several types:– BoneBone– BloodBlood– CT proper: dense and looseCT proper: dense and loose– AdiposeAdipose– CartilageCartilage

Examples: Connective

• CT proper:• Collagen fibers

(vitamin C)– Loose: ECM– Dense: tendons and

ligaments

p. 159 A

Examples: Connective

• BoneBone

– Dense, hard Dense, hard mineral matrixmineral matrix

– Replaced every Replaced every 9 months.9 months.

p. 161 E

Examples: Connective

• Blood– To circulate

materials throughout the organism

– RBC’s: contain hemoglobin to allow for oxygen to be carried to the tissues.

p. 160 C

Examples: ConnectiveExamples: Connective• Cartilage: vary in #

of fibers and blood supply– Hyaline: ribs,

trachea, joints– Elastic: ears, larynx– Fibro: spinal chord

p. 160 D

Examples: Connective

• Adipose tissue:

– Insulation

– Energy Storage

p. 159 A

Muscle tissueMuscle tissue

• Function: Able to contract for Function: Able to contract for locomotion.locomotion.

• Three types: skeletal, cardiac and Three types: skeletal, cardiac and smoothsmooth

Muscle tissueMuscle tissue

• Skeletal: voluntary, striated, multinucleate cells

• Muscles attached to bones for voluntary movement

p. 161 A

Muscle tissue

• Smooth:– Non-striated,

spindle-shaped, uni-nucleate involuntary cells

• Muscles found in digestive tract, respiratory tract, etc.

p. 161 B

Muscle tissue

• Cardiac:involuntary, striated, branched, uni-nucleate cells

• Only found in the heart

p. 161 D

Nervous tissueNervous tissue

• Function: Respond to Function: Respond to

stimuli and transmit impulses.stimuli and transmit impulses.

• Cells are called neuronsCells are called neurons

• Composed of cell body, axon and Composed of cell body, axon and dendrites. dendrites.

• Single cell may run up to several feet Single cell may run up to several feet long. long.

p. 161 IV

Life Processes

• Respiration• Circulation• Responsiveness• Boundary

Maintenance• Movement• Adaptation

• Digestion• Absorption• Assimilation• Excretion• Reproduction

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• Blocked coronary artery

• Alveoli of lungs with pneumonia

• Emphysema in alveoli of lungs

• Sickle cell anemia

• Parkinson’s disease

• Cervical Human papillomavirus

• Esophageal Cancer

• Normal Bone *Diseased

• Osteoporosis

• Infected mammary gland from silicone leak

» Stomach ulcer

• Cardiac tissue after cocaine use

• Cardiac tissue following myocardial infarction