Tissue Types

Tissues- a group of cells performing a similar function

• Epithelial• Connective• Muscle• Nervous

Epithelial- General Characteristics

Linings, coverings and glands Protection, absorption, filtration, or secretion Closely packed (no leaks, please!), often with

tight junctions Apical (free) surface Lower surface-basement membrane No blood supply (avascular) Capable of regeneration

Simple Epithelium

Simple squamous thin, single layer tightly packed membranes that allow

for transmission of a fluid, gas, nutrient

also form serous membranes

Simple Epithelium

Simple Cuboidal One layer thick, boxy

cells Glands & ducts Walls of tubules

Simple Epithelium

Simple Columnar Single layer, column

shaped cells Often, Goblet cells are

embedded within the layer

Lines entire GI tract Mucous membranes

(note spelling: mucous- adj. vs. mucus-n.)

Simple Epithelium

Pseudostratified Columnar Rest on basement

membrane Nuclei at different

heights; thus it looks like layers

Absorption/excretion Some types are ciliated

Stratified Epithelia

Stratified Squamous Most common in body Several layers Found where tissue

might take a beating, such as esophagus, mouth, outer skin

Transitional Epithelium

Highly modified stratified epithelium

Linings of some organs of the urinary system

Lots of stretching Basal layers cuboidal or

columnar; other layers variable

When organ is full, layers flatten out and look like squamous cells

Connective Tissue

Cells within a matrixCells loosely packed, with spaces between

themMatrix runs from liquid, to fibers, to rigid

and hard

Bone (Osseous tissue)

Bone cells sit in holes in matrix called lacunae

Matrix calcified & very hard

Protective, framework of body

Cartilages

Hyaline Most common Rubbery matrix; flexible Larynx, ribs/sternum,

joints Fetal skeleton

Fibrocartilage

Compressible Intervertebral discs

Elastic Cartilage

Obviously, connective tissue that needs to have flexibility

Ear lobes, tip of nose

Dense Connective Tissue

Also known as fibrous CT

Collagen fibers for matrix

Fibroblast cells Strong, ropelike Tendons & ligaments Lower dermis of skin

Loose Connective Tissue

Softer; more cells & less fiber

3 types: areolar, adipose & reticular Areolar: cushions &

protects Stores water (edema) Cobweb appearance

Adipose: fat tissue Appear empty Insulate & protect

Loose CT (con’t)

Reticular Delicate network Limited sites: lymph

nodes, spleen, bone marrow

Supports free blood cells

Blood-Vascular Tissue

Fluid matrix, plasma Protein molecules

constitute the fibers of the matrix

Atypical CT Transport of nutrients,

gases, wastes, etc. RBCs, WBCs and

platelets

Muscle Tissue

SkeletalVoluntary, striated,

attached to bone

SmoothInvoluntary, non-striated

walls of organs,

CardiacInvoluntary, striated, heart

tissue

Nervous Tissue

Neurons Cell body, cell

processes that can be very long

Brain, spinal cord, nerves

Neuroglia: “nurse cells”Supporting cells of the matrix

Good review web site!

faculty.ircc.edu/.../histology_flash_cards.htm