BIO-111 Chapter 4 (Epithelial + Muscle Tissues)

The four types of tissues

Epithelial, connective, muscle, nerve

What holds epithelial cells together?

Tight junctions and desmosomes

What supports epithelial tissue?

Connective tissue

What are the two parts of the basement membrane?

Reticular and basal laminae

Is epithelial tissue vascular or avascular?

Avascular

What is the difference between vascular and avascular?

• Vascular = has blood vessels

• Avascular = does NOT have blood vessels

What does innervated mean?

Supplied by nerve fibers

What does "regenerative" mean for epithelial tissue?

Rapidly replaces lost cells by cell division

What is the difference between simple and stratified epithelium?

Simple has one layer; stratified has two or more layers

What are the three shapes used to classify epithelial cells?

Squamous, cuboidal, and columnar

How do squamous, cuboidal, and columnar cells differ in shape?

Squamous = flat; cuboidal = cube-shaped; columnar = tall

What is the structure of simple squamous epithelium?

Single layer of flattened cells with disc-shaped nuclei and sparse cytoplasm

What are the functions of simple squamous epithelium?

Diffusion, filtration, friction-reducing lining

Where is simple squamous epithelium located?

Pic: air sacs of lung tissue

Kidney glomeruli, heart, blood vessels, lymphatic vessels, and serosae

What is the structure of simple cuboidal epithelium?

Single layer of cube-like cells with large, spherical central nuclei

What are the functions of simple cuboidal epithelium?

Secretion and absorption

Where is simple cuboidal epithelium located?

Kidney tubules, ducts and secretory portions of small glands, and ovary surface

What is the structure of simple columnar epithelium?

• Single layer of tall cells with oval nuclei; many contain cilia

• Goblet cells are often found in this layer

What are the functions of simple columnar epithelium?

Secretion and absorption

Where is nonciliated simple columnar epithelium located?

Digestive tract and gallbladder

Where is ciliated simple columnar epithelium located?

Small bronchi, uterine tubes, and some regions of the uterus

What is the structure of pseudostratified columnar epithelium?

• Single layer of cells with different heights; some do not reach the free surface

• Nuclei are seen at different layers

What is the function of pseudostratified columnar epithelium?

Secretion and propulsion of mucus

Where is pseudostratified columnar epithelium located?

Pic: trachea

Male sperm-carrying ducts (nonciliated) and trachea (ciliated)

What is the structure of stratified squamous epithelium?

Thick membrane composed of several layers of flat cells

What is the function of stratified squamous epithelium?

Protection of underlying areas subjected to abrasion

Where is stratified squamous epithelium located?

Pic: esophagus

Skin’s epidermis (keratinized); linings of esophagus, mouth, and vagina (nonkeratinized)

How common is stratified cuboidal epithelium?

Quite rare in the body

What are the structure and location of stratified cuboidal epithelium?

Typically two cube-shaped cell layers thick; found in some sweat and mammary glands

How widely distributed is stratified columnar epithelium?

Limited distribution in the body

Where is stratified columnar epithelium located?

Pharynx, male urethra, some glandular ducts, and transition areas between two other epithelial types

What is the structure of transitional epithelium?

Several cell layers; basal cells are cuboidal and surface cells are dome-shaped

What is the function of transitional epithelium?

Stretches to permit the distension of the urinary bladder

Where is transitional epithelium located?

Urinary bladder, ureters, and part of the urethra

What is a gland?

One or more cells that make and secrete an aqueous fluid

How are glands classified by their site of product release?

Endocrine or exocrine

How are glands classified by the number of cells forming the gland?

Unicellular or multicellular

What are endocrine glands?

Ductless glands that produce hormones

What do endocrine glands secrete?

Amino acids, proteins, glycoproteins, and steroids

How do exocrine glands differ from endocrine glands?

Exocrine glands are more numerous than endocrine glands

Where do exocrine glands secrete their products?

Onto body surfaces (skin) or into body cavities

What are examples of exocrine glands?

Mucous, sweat, oil, and salivary glands

What is the only important unicellular gland?

Goblet cell

What are multicellular exocrine glands composed of?

A duct and secretory unit

How are multicellular exocrine glands classified?

By simple or compound duct type and structure of their secretory units

What is the structure of skeletal muscle tissue?

Long, cylindrical, multinucleate cells with obvious striations

What is the function of skeletal muscle tissue?

Initiates and controls voluntary movement

Where is skeletal muscle tissue located?

Skeletal muscles that attach to bones or skin

What is the structure of cardiac muscle tissue?

Branching, striated, uninucleate cells interlocking at intercalated discs

What is the function of cardiac muscle tissue?

Propels blood into the circulation

Where is cardiac muscle tissue located?

Walls of the heart

What is the structure of smooth muscle tissue?

Sheets of spindle-shaped cells with central nuclei that have no striations

What is the function of smooth muscle tissue?

Propels substances along internal passageways, such as peristalsis

Where is smooth muscle tissue located?

Walls of hollow organs

What characterizes inflammation caused by tissue trauma?

Dilation of blood vessels, increased vessel permeability, redness, heat, swelling, and pain

What happens during tissue trauma?

Inflammation occurs, causing blood vessels to dilate and become more permeable

What happens during the organization and restored blood supply stage of tissue repair?

The blood clot is replaced with granulation tissue

What are the two possible outcomes of tissue repair?

Regeneration and fibrosis

What happens to the surface epithelium during tissue repair?

It regenerates and the scab detaches

What happens as fibrous tissue matures during tissue repair?

It begins to resemble the adjacent tissue

What is the result of tissue repair?

Fully regenerated epithelium with underlying scar tissue

What are the three primary germ layers?

Ectoderm, mesoderm, and endoderm

When are the three primary germ layers formed?

Early in embryonic development.

What do the three primary germ layers eventually specialize to form?

The four primary tissues

Which primary tissue arises from the ectoderm?

Nerve tissue

Which tissues arise from the mesoderm?

Muscle, connective tissue, endothelium, and mesothelium

Which structures mostly arise from the endoderm?

Most mucosae

Which germ layers can epithelial tissues arise from?

All three germ layers