Tissues

Histology- the study of tissues

4 tissue types

1. Epithelial Tissue– Covers both internal and external surfaces

2. Muscle Tissue– Highly specialized tissue designed to contract

3. Nervous Tissue– 2 types of cells neurons (carry signal) and neuroglia

(care for and support neurons).

4. Connective Tissue– Connects, protects, supports, insulated, energy

storage, blood formation, & body tissue repair (Scars)

Epithelial Tissue

• # of layers– Simple one– Stratified >1

• Cell shape– Cuboidal- Cube shaped– Columnar – column

shaped– Sqamous- squished like a

pancake.

Epithelial Tissue- SimpleSquamous Cuboidal

Columnar

Simple Squamous

Nucleus

Cell MembraneSin

gle la

yer o

f

Flatten

ed ce

lls

Simple Cuboidal

Nucleus

Cell Membrane

Basement Membrane

Single

laye

r

Cube

shap

edce

lls

Simple Columnar

NucleusCell Membrane

Basement Membrane

Single layerColumn shaped

cells

Epithelial Tissue- Stratified

Squamous Cuboidal Columnar

Stratified Squamous

NucleusCell Membrane

Basement Membrane

Stratified Cuboidal-Not on practical

• Found:– Sweat gland ducts– Ovarian follicular cells– Salivary gland ducts

• Function:– Secretion– Absorption– Protection against

infection

Stratified Columnar- Not on practical

• Found:– Mammary gland ducts– Larynx– Portions of the male

urethra

• Function– Protection– secretion

ExceptionsPseudostratified Ciliated columnar

Transitional Epithelium

Collapsed Distended

Pseudostratified Ciliated columnar

NucleusCell Membrane

Basement Membrane

Cilia

Free surface

Transitional Epithelium

Cell Membrane

Nucleus

Basement membrane

Muscle TissueHighly specialized tissue designed to contract

• 3 types:

Skeletal Muscle Cardiac Muscle Smooth Muscle

Skeletal Muscle

Multiple Nuclei

Striations

MuscleFibers

Cardiac Muscle

NucleusStriations

IntercalatedDisk

Smooth Muscle

NucleusMuscle cell

Nervous Tissue

• Two major cell populations1. Neurons- specialized cells that receive stimuli

and conduct impulses all over the body2. Neuroglia- special cells that protect, support,

and insulate the more delicate neurons

Mot

or N

euro

n

Multipolar neuron/ Motor neuron

Axon

Glial Cells

Nucleus

Nucleolus

Dendrite

Axon Hillock

Cell body

Connective Tissue• Usually have a rich blood supply• Composed of many cell types• Great deal of non-cellular, nonliving material

between cells (Matrix)

Jelly Fibers

•Interstial fluid, cell adhesion proteins, & proteoglycans•Dependent on combo is can be liquid, semisolid, gel-like or very hard

•Collagen fibers: very strong and flexible but not elastic•Elastic fibers- can be stretched but return to their original shape•Reticular fibers- fine collagen fibers, not strong but fill spaces

Connective Tissues (CT)- all derived from mesenchyme

1. CT proper– Areolar CT– Dense CT

A. RegularB. Irregular

– Adipose– Reticular

2. CartilageA. Hyaline CartilageB. FibrocartilageC. Elastic cartilage

3. Bone4. Blood

Loose (Areolar) Connective tissue

Collagen Fiber

Reticular Fiber

Elastic fiber

Nucleus

Loose connective tissueAdipose Tissue Reticular tissue

Adipocyte

Nucleus

Cell membrane Reticular fiber

Cell of organ being supported by the fibers

Dense connective tissue

Dense Regular CT Dense Irregular CT

Nucleus

Collagen Fiber

Collagen Fiber

Nucleus

CT-Cartilage

Hyaline Cartilage fibrocartilage Elastic Cartilage

Hyaline Cartilage

ChondrocyteLacuna

Perichondrium

Fibrocartilage

Chondrocyte

Collagen fibers

Elastic Cartilage

Chondrocyte

Lacuna

Elastic Fibers

Bone

ConcentricLamella

Lacuna

Central canal

Osteon

BloodRed Blood Cell

White Blood Cell

Plasma

Platelet