chapter 5 tissues. epithelial covers the body surface and organs, lines the inner cavities, glands...

Chapter 5

Tissues

Epithelial• Covers the body surface and organs, lines the

inner cavities, glands• External- protects from drying out, injury, and

bacteria• Internal-protection, secretions, specialization

(mucus, cilia, microvilli)• Cells packed tightly together, little matrix• Lack blood vessels• Anchored to underlying tissue at basement

membrane• Squamous, cuboidal, columnar• Simple (single layer) Stratified (several layers)

Simple Squamous• Flattened cells• Single layer• Found in the body

where the layer of cells must be thin to permit efficient diffusion and filtration

• Thin, delicate, easily damaged

• EX: blood vessels (capillaries) alveoli (lungs) body cavities

Simple Squamous Epithelial

Simple Cuboidal

• Single layer, cubed shaped cells

• kidneys, liver, ovaries, glands (salivary, thyroid), pancreas

Simple Cubodial Epithelial

Simple Columnar• Elongated, single layer• Frequently secrete a

product, also absorption

• May be ciliated (fallopian tubes) or non-ciliated

• May have microvilli for absorption (intestines)

• Wall of the uterus, stomach, small intestines

Simple Columnar Epithelial

Stratified Squamous• Must resist

constant wear and tear

• Thick with layers• Outer layer of skin is

strengthened and toughened with keratin (protein)

• Mouth, anus, esophagus, vagina- no keratin here

Pseudostratified Epithelium

• “appears” to be layered but is not

• Cilliated cells line respiratory tract, nasal, trachea, bronchi

• Contain goblet cells which secrete mucus and the ciliated cells move debris along the surface

Pseudostratified Tissue

Transitional Epithelium

• Ability to expand and regain its shape

• Urinary bladder, uterus, etc.

Glandular Epithelium• Manufacture and secrete a

substance• “Gland”• Singular- mucus goblet cell or

Group cells• Exocrine- secrete into ducts that

open onto surfaces like the skin or digestive tract (Salivary, sweat)

• Endocrine- secrete directly into the bloodstream (Thyroid, pituitary)

Glands

Body Membranes

• Lines the internal sides of cavities and surrounds organs; line the tubes that open to the outside

• Contain other structures passing through it…blood vessels, nerves, etc.

• Divide areas of the body into compartments

• Anchor organs to other structures

Mucus Membranes

• Line the interior wall of organ and tubes that open to the outside

• Digestive, respiratory, urinary, reproductive• Epithelium overlying connective tissue• ET contains goblet cells that secrete mucus• Mucus protects from bacteria and viruses• Mucus in stomach protects from digestive

enzymes

Serous Membranes• Line the thoracic and abdominal cavities and their

organs• Simple squamous overlying connective tissue• Secrete a clear watery fluid that provides lubrication• Pleural membranes in thoracic cavity…pleurisy

(infection of the pleural and parietal membranes around the lungs)

• Pericardium (surrounds the heart)• Peritoneum –abdominal cavity….Peritonitis- infection of

the peritoneum (appendix bursts)• Mesentery- peritoneum doubles back to form support

for internal organs (intestines)• Parietal (body wall) … Visceral (organ lining)

Synovial Membranes• Line the cavities of freely movable joints (knee,

elbow, shoulder)does not contain epithelial tissue…connective tissue (cartilage)

• Secrete a clear watery liquid (synovial fluid) that lubricates the ends of the opposing bones….nourishes the cartilage at the ends of the bones

• Rheumatoid arthritis- membrane becomes inflamed and grows thicker…fibrous tissue invades the joint and makes the joint bony and stiff

Meninges• Membranes that surround the brain and

spinal cord

• All connective tissue

• Meningitis – infection of the meninges

Cutaneous Membrane

• Skin

• Thin outer layer of stratified squamous attached to a thicker layer of connective tissue