A&P Exam 2

What is tissues?

Groups of similar cells that perform a similar function

What are the 4 types of tissues in the body?

• Epithelial

• Connective

• Muscle

• Nervous

What is the general functions of epithelial tissue?

• Covers body surfaces

• Lines hollow organs, body cavities and ducts

• Forms glands

• Acts as a selective barrier

• Secretory surface

• Protective surface

• Sensations

• Filtration

• Absorption

What is the general function of connective tissue?

Protects and supports the body and its organs

What is the general functions of muscle tissue?

• Generates forces needed to make body structures move

• Generates body heat

What is the general function of nervous tissue?

Detects and responds to changes in the body’s internal external environments

What are the characteristics of the epithelial tissues?

• Cells arranged in continuous sheets in single or multiple layers

• Attached to a basement membrane

• Cells are packed together with little intercellular space between plasma membranes

• Avascular (Lack of blood)

  • Blood vessels bring nutrients and remove wastes

• High rate of mitosis for constant repair and renew itself

• Extensive Innervation (Rich nerve supply)

What are surfaces of epithelial tissue?

Apical, lateral, basal

How can epithelium tissue be classified by?

Cell shape and layers

What are the cell shapes for epithelium tissue

• Squamous

• Cuboidal

• Columnar

• Transitional

Squamous

Flattened irregularly shaped cells

What is the function of squamous cells?

Allow rapid passage of substances

Cuboidal

Cube-shaped cells

What is the function of cuboidal cells?

Secretion and absorption (3)

Columnar

Elongated Cells

What is the function of columnar cells?

Protect underlying tissues

Can columnar cells have cilia or microvilli?

Yes

Transitional

Cells change shape from flat to cuboidal and back

What is the function of transitional cells?

Allows for stretching and relaxation of an organ

What are the cell layers of epithelium tissue?

• Simple

• Stratified

• Pseudostratified

Simple

Single layer of cells that function in diffusion, osmosis, filtration, secretion & absorption

Stratified

2 or more layers that protect underlying tissues where abrasive forces exist

Pseudostratified

Appears to have multiple layers but is truly a simple epithelium

Simple Squamous Epithelium cells

Single layer of flat cells

Simple Squamous epithelium cell Locations

Lines heart, blood and lymph vessels, air sacs of lungs

Simple Squamous epithelium cell functions

Filtration, secretion, diffusion, and osmosis

Simple cuboidal epithelium cells

Single layer of cube-shaped cells; can be ciliated or nonciliated

Simple cuboidal epithelium cell locations

Surface of ovary, capsule of lens of eye, lines kidney tubules and ducts of many glands

Simple cuboidal epithelium cell functions

Secretion & absorption

Simple Columnar epithelium cells

Single layer of elongated cells

Nonciliated Simple columnar epithelium cell Locations

Lines GI tract, ducts, glands, and gallbladder

Nonciliated Simple columnar epithelium cell Functions

Secretion and absorption

Ciliated Simple Columnar epithelium cell Locations

Lines bronchioles of respiratory tract, uterine tubes, and uterus

Ciliated Simple Columnar epithelium cell Function

Moves substances

Pseudostratified Columnar epithelium cell

Single layer of cells but appears to be multiple layers; can be ciliated or nonciliated

Pseudostratified Columnar epithelium cell locations

Lines airways of respiratory tract and lines ducts of glands

Pseudostratified Columnar epithelium cell Function

Secretion and movement of mucus; and protection

Stratified Squamous epithelium cells

Flattened/squamous cells on apical surface and may have cuboidal or columnar cells in deeper layers

Stratified squamous epithelium cell function

Protection

Nonkeratinized Stratified squamous epithelium cells

Apical cells that are alive

Nonkeratinized Stratified squamous epithelium cell locations

Lines oral cavity, esophagus, and vagina

Keratinized stratified squamous epithelium cells

Apical cells that are dead and filled with keratin (protein)

Keratinized stratified squamous epithelium cell locations

Epidermis of the skin

Stratified cuboidal epithelium cells

Apical cells that are cuboidal over squamous cells

Stratified cuboidal epithelium cell locations

Ducts of adult sweat glands & parts of male urethra

Stratified cuboidal epithelium cell function

Protection & secretion

Stratified columnar epithelium cells

Several layers of irregularly shaped cells; only apical layer has elongated cells

Stratified columnar epithelium cell locations

Lines part of urethra & excretory ducts of some glands

Stratified columnar epithelium cell functions

Protection and secretion (4)

Transitional epithelium cells

Cells that vary from flat to cuboidal

Transitional epithelium cell locations

Lines urinary bladder, portions of ureters, and urethra

Transitional epithelium cell functions

Permits distension and relaxation

Glandular epithelium

Single or groups of cells that secrete substances into ducts, onto a surface or into the blood

Glandular epithelium function

Secretion

Endocrine gland characteristic

Lacks ducts (tubes)

Endocrine glands functions

• Secretes hormones directly into interstitial fluid and blood

• Regulate metabolic and physiologic activities to maintain homeostasis

What are some endocrine glands?

Pituitary, thyroid, adrenal glands

Exocrine Gland functions

Secrete substances into ducts that empty onto the surface of “covering and lining” epithelium

What are some examples of exocrine glands?

Sweat, salivary, and digestive glands & pancreas

Connective tissue characteristics

• Designed to support, protect, and bind organs

• Highly vascular (Rich blood supply)

• Consists of cells, protein fibers, and ground substance

Extracellular matrix

Fibers + ground substance

What are resident cells?

Stationary connective tissue cells

What are the 4 types of resident cells?

• Fibroblasts

• Adipocytes

• Mesenchymal cells

• Macrophages

Fibroblasts

• Large, flat, branching cells

• Most numerous cell in connective tissue

What is the function of fibroblasts?

Secretes fibers and part of the ground substances of extracellular matrix

Adipocytes

Fat cells or adipose cells

What is the function of adipocytes?

Store triglycerides/lipids

Mesenchymal cells

Embryonic cells

What is the function of mesenchymal cells?

Divide when tissue is damaged

Macrophages

Derived from white blood cell

What is the function of macrophages?

Phagocytize (engulf) damaged cells or pathogens

Wandering connective tissue cell characteristics

• Continuously move throughout the connective tissue

• Components of the immune system and are primarily types of leukocytes

Mast cells

Involved in the inflammatory response

Plasma cells

Produce antibodies (proteins that immobilize foreign material)

Free macrophages

Phagocytic cells that move throughout the tissue

Neutrophils

Phagocytize bacteria

Lymphocytes

Attacks and kills foreign materials

Ground substance

• Non-living material produced by the connective tissue cells

• May be fluid, semifluid, gelatinous, or calcified

• Functions - Supports and binds cells together

Protein fibers

Has 3 types of fibers embedded in the extracellular matrix designed to strengthen and support the tissue

What are the 3 types of protein fibers?

• Collagen

• Elastic

• Reticular

Collagen fibers

• Very strong and yet flexible

• Found in most CT especially bones, cartilage, tendons, and ligaments

Elastic fibers

• Provide strength, stability, and elasticity

• Found in skin, blood vessel walls, and lungs

Reticular fibers

• Provide support and strength to certain tissues

• Found in stroma (supporting framework of soft organs)

What are 2 types of Embryonic CT?

• Mesenchyme

• Mucous

What are 5 types of mature CT?

• Loose

• Dense

• Cartilage

• Bone

• Blood

Loose connective tissue

• Supports and surrounds structures and organs

• Contains few cells, sparse & irregularly arranged protein fibers, and abundant ground substance

What are 3 types of loose connective tissue?

• Areolar

• Reticular

• Adipose

Areolar CT

• Most widely distributed CT in body

• Contains fibroblasts, macrophages, plasma cells, mast cells, and adipocytes

• Contains collagen, elastic, and reticular fiber

Where is the areolar CT found?

Subcutaneous layer of tissue deep to skin, dermis of skin, and surrounds organs and nerves

What is the function of areolar CT?

Protects and binds

Reticular CT

• Contains interlacing reticular fibers, fibroblasts, and leukocytes

What is the function of reticular CT?

Forms the stroma & binds smooth muscle cells

What are the locations of reticular CT?

Liver, spleen, lymph nodes, and red bone marrow

Adipose CT

Fibroblasts produce adipocytes which specialize in storing triglycerides

What is the function of adipose CT?

• Supports and protects various organs

• Good insulator

• Major reserve for energy

Where is the adipose CT located?

Subcutaneous layer and surrounds some organs

Dense CT

• Composed primarily of protein fibers

• Contains less ground substance than loose CT

What are 3 types of dense CT?

• Dense Regular

• Dense irregular

• Elastic

Dense Regular CT

Consists of collagen fibers in bundles with fibroblasts in rows between bundles

What is the function of dense CT?

Provides strong attachment between structures