Hierarchy Of Organization

Atoms -> molecules ->cells-> TISSUES->organs -> organ systems -> organisms -> poulations -> communities -> ecosystems -> biosphere

Study of Tissues

Histology

Tissue Types

Epithelial Tissue

Connective Tissue

Muscle Tissue

Neural Tissue

Epithelial Tissue

cover exposed surfaces (lininigs) both external and internal

Connective Tissue

Fills internal spaces

Connects, Supports, Transports 

a.k.a tendon, blood, bones

Muscle Tissue

 Movement

 Neural Tissue

Transmission of Information

Epithelial Tissue 

Characteristics:

(5)

   *Polarity (apical and basal surfaces)

   *Attachment (basement membrane)

   *Tightly Bound Cells

   *Avascular (nutrients via diffusion)

   *Regenteration (actively in 24 (degrees) cell cycle)

Apical

Top of Polarity

Protects against environment

Basal

Bottom of Polarity

Conntects to tissue

Epithelial Tissue

Functions:

 (4)

 *Physical Protection

*Control Permeability (controls stuff coming in and out)

*Sensation

*Secretion (glands)

 Secretion ->

Exocrine =

Secretions onto epithelial surface

Secretion ->

Endocrine =

Secretions released to surrounding fluids

Cilia

Increase movement

Microvili

Increase Surface Area

Epithelial Connections

Special Protiens connect cells to each other at

Tight Junctions

Desmosomes

Gap Junctions

Tight Junctions

*Apical

*In-between cells

*Keeps fluids from leaking between cells

Desmosomes

*Connect cell to cell

*Attach to Cytoskeleton

Gap Junctions

 *Interlock Cells

*Provide channels between cells

Basement Membrane

 Holds epithelium to rest of body

Proteins and glycoproteins from basal lamina and reticular lamina

******************************************

Epithelium continuosly replaced by stem cells near basment layer.

 Epithelium Classification

Simple epithelial tissue

Single Layer of Cells

Epithelium Classification

Stratified epithelial tissue=

Stacked Layer of Cells

Cell Shapes

Squamous

*Flat

*Irregular shape

*Lining ventral body cavity

*Mouth

*Kidney tubules

*Blood Vessels

*Where thin/permeable

*required

Cell Shapes

 Cuboidal

*Box Shaped

*Ducts

*Glands

Cell Shape

Columnar

*Long and narrow

 *(Simple only)

 *Secretion

 *Absorption

 *Cilia and Microvili

*Small Intestine

*Nasal Cavity

Epithelium and glands

 Endocrine glands =

To follow

Exocrine Glands =

 &

3 Different Kinds

 = Secrete into Ducts

*Merocrine

*Apocrine

*Holocrine

 Merocrine

Secretion via exocytosis 

aka

mucous

Apocrine