Chapter 5 - Tissues

Tissues

group of similar cells with a common function

the study of Tissues

• Epithelial tissue • Connective tissue • Muscle tissue • Nervous tissue

• Cover organs and body surface • Line cavities and hollow organs • Make up glands • Have a free surface on outside, and basement membrane on inside • Lack blood vessels (avascular), and nutrients diffuse to epithelial tissue from underlying connective tissue • Cells readily divide; injuries heal rapidly • Cells are tightly packed

Squamous - flat Cuboidal - cube-shaped Columnar - tall

simple (one layer of cells), stratified (2 or more layer of cells), or pseudostratified (appears layered, but is not)

• Single layer of thin, flat cells • Substances pass easily through air sacs (alveoli) and capillaries • Thin and delicate, can be easily damaged • Found in diffusion and filtration sites • Makes up walls of air sacs (alveoli) and capillaries • Lines blood and lymphatic vessels

• Single layer of cube-shaped cells • Secretion and absorption • Lines kidney tubules, thyroid follicles, ducts of some glands • Covers ovaries

• Single layer of elongated cells • Nuclei usually at same level, near basement membrane. • Sometimes have microvilli, cilia, goblet cells (secrete mucus) • Secretion and absorption • Lines uterus, stomach, intestines

• Single layer, but appears layered • Nuclei at 2 or more levels • Cells vary in shape, but all reach basement membrane • Often has cilia, goblet cells • Protection from infection • Lines respiratory passageways

• Many cell layers; thick • Protective layer • Outermost cells are squamous, deeper cells are cuboidal • New cells produced in deep layers, push older cell toward free surface • Outer layer of skin, called the epidermis, is keratinized • Lines oral cavity, vagina, anal canal

• 2 to 3 layers of cube-shaped cells • More protection than 1 layer • Lines ducts of mammary, sweat, and salivary glands, and pancreas

• Several layers of cells • Top layer of elongated cells • Cube-shaped cells in deeper layers • Lines part of male urethra, ducts of exocrine glands

• Many cell layers • Cube-shaped and elongated cells • Changes shape and appearance with increased tension; stretches • Forms barrier and lining that can expand • Lines urinary bladder, ureters, and part of urethra

Composed of cells that produce and secrete substances into ducts or body fluids

Endocrine Glands & Exocrine Glands

secrete into tissue fluid or blood

secrete into ducts that open onto a surface

Unicellular & Multicellular

Composed of one cell, such as a goblet cell (secretes mucus)

Composed of many cells; can be simple or compound; examples: sweat and salivary glands

Merocrine Glands & Apocrine Glands & Holocrine Glands

Secrete fluid products by exocytosis; salivary and sweat glands, pancreas