Ch. 4 Anatomy Lecture

Epithelial tissue, connective tissue, and membranes

Tissue

A group of similar cells specialized to perform a specific function

What are the 4 types of tissues?

Epithelial, connective, muscle, and neural tissue

Epithelial tissue location

• Cover surfaces

• Line cavities

• Form glands

Epithelial tissue function

• Physical protection

• Selective permeability

• Secretion

• Sensation

Epithelial tissue characteristics

• Mainly cells; little extracellular material

• Exhibits polarity; consists of apical (free/top) surface and basal (fixed/bottom) surface

• Attached to basement membrane

• Avascular

• Richly innervated

• High regeneration

What type of tissue?

• Simple squamous epithelium

• Function: diffusion and filtration

• Location: alveoli, endothelium (lines cardiovascular and lymphatic system), mesothelium (forms serous membranes of body cavities)

• Flat and fast!

What type of tissue?

• Simple cuboidal epithelium

• Function: secretion and absorbtion

• Location: kidney tubules; surface of ovaries; thyroid gland follicles; secretory glands (K.O.T.S.)

What type of tissue?

• Non-ciliated simple columnar epithelium

• Function: absorption and mucus secretion

• Location: lining of digestive tract

What type of tissue?

• Ciliated simple columnar epithelium

• Function: movement of mucus and oocytes via cilia

• Location: lining of uterine tubes; bronchioles of respiratory tract

What type of tissue?

• Ciliated pseudostratified columnar epithelium

• Function: movement of mucus via cilia

• Location: lining of respiratory tract

What type of tissue?

• Keratinized stratified squamous epithelium

• Function: protection of underlying tissue

• Location: epidermis of skin

What type of tissue?

• Non-keratinized stratified squamous epithelium

• Function: protection of underlying tissue in a moist environment

• Location: oral cavity; pharynx; esophagus; anus; vagina

What type of tissue?

• Transitional epithelium

• Contain binucleated cells

• Function: stretches and relaxes to accommodate urine

• Location: Lining of urinary bladder, ureters, and urethra

Gland

Epithelial cells that produce a secretion

Exocrine glands

Release secretions via ducts onto the surface of epithelial tissue

Goblet cells

Unicellular exocrine glands

Serous glands

Produce a watery secretion (ex. sweat, milk, tears, and digestive juices)

Mucous glands

Produce a slimy secretion that contains mucin protein

Mixed glands

Produces serous and mucous gland secretions (ex. saliva)

Connective tissues

• Function: fill internal spaces; support other tissues; transport materials; store lipids

• Characteristics: specialized cells, extracellular protein fibers, and ground substance

What type of tissue?

• Areolar connective tissue

• Type of loose connective tissue proper

• Contains a variety of cells and fibers

• Function: packs around and binds organs

• Location: surrounds nerves, vessels, and organs; subcutaneous layer

• Areolar = around

What type of tissue?

• Adipose connective tissue proper

• A type of loose connective tissue proper

• Contains mostly adipocytes

• Function: protects; stores fat; insulates

• Location: around organs; subcutaneous layer

What type of tissue?

• Reticular connective tissue proper

• A type of loose connective tissue proper

• Contains reticular fibers and leukocytes

• Function: the framework of delicate organs

• Location: organs in the lymphatic system (spleen, thymus, and lymph nodes); bone marrow

What type of tissue?

• Dense regular connective tissue

• A type of dense connective tissue proper

• Contains mostly collagen fibers

• Function: strength and flexibility in one direction

• Location: tendons; ligaments

What type of tissue?

• Dense irregular connective tissue

• A type of dense connective tissue proper

• Contains mainly collagen fibers

• Function: strength in all directions

• Locations: dermis of the skin; capsule of organs

What type of tissue?

• Elastic connective tissue

• A type of dense connective tissue proper

• Contains mainly elastic fibers

• Function: allows stretching

• Location: elastic connections of vertebral spinous processes; walls of arteries

Fibroblasts

Produce protein fibers and ground substance

Macrophages

Phagocytize foreign materials

Mast cells

Release histamine and heparin to stimulate local inflammation

Plasma cells

Form antibodies

Lymphocytes

Attack foreign materials

Neutrophils

Phagocytizes bacteria

Perichondrium

A layer of dense connective tissue proper that surrounds cartilage

What type of cartilage?

• Hyaline cartilage

• A type of supporting connective tissue

• Contains chondrocytes and dissolved protein fibers

• Function: reduces friction; provides flexible support

• Location: articular ends of long bones, larynx, trachea, and nose

• Air, nose, and ends of bones!

What type of cartilage?

• Elastic cartilage

• A type of supporting connective tissue

• Contains chondrocytes and elastic fibers

• Function: allows flexibility

• Location: external ear; epiglottis of larynx

What type of cartilage?

• Fibrocartilage

• A type of supporting connective tissue

• Contains chondrocytes and collagen fibers

• Function: resists compression

• Location: pads within knee joint; between pubic bones and pelvis; intervertebral discs

Bone

• Ground substance is a semi-solid substance that hardens when mineral deposits are added

• Contains osteocytes and collagen fibers

• Two types: compact and spongy

What type of tissue?

• Blood

• A type of fluid connective tissue

• Contains red blood cells, white blood cells, and plasma

Lymph

• Fluid connective tissue

• Not viewable histologically

Membrane

A combination of epithelial and connective tissues

Serous membrane

• Location: line internal body cavities (ex. pleura, pericardium, and peritoneum)

• Epithelial cells secretes transudate

• A combination of simple squamous epithelium and areolar connective tissue

Mucus membrane

• Location: line passageways that open to the outside environment (ex. respiratory, digestive, reproductive, and urinary tracts)

• Epithelial cells secrete mucus

• A combination of simple columnar epithelium or pseudostratified epithelium and areolar connective tissue

Synovial membrane

• Location: line joint spaces

• Epithelial cells secrete synovial fluid

• A combination of areolar, fibrous, and adipose connective tissue; no true epithelium

Cutaneous membranes

• Location: the skin

• A combination of keratinized stratified squamous epithelium and connective tissue