BODY TISSUES

BODY TISSUES

• Epithelial• Connective• Muscle• Nervous

Epithelial Tissues

• Tightly connected: covering body surfaces and lining body cavities

• Shapes vary: squamous, cuboidal, columnar

• Layers of cells: simple = one stratified = several

Connective Tissue• Connects and supports body parts• Cells scattered in matrix (protein fibers and

ground substance)• Loose, Dense, Specialized

1. Loose connective tissue: areolar and adipose – supports epithelium and body parts

2. Dense connective tissue: ligaments, tendons, dermis

3. Specialized: cartilage (chondrocytes), bone(osteocytes), blood (erythrocytes and leukocytes)

Muscle Tissue

• Skeletal (striated)• Smooth• Cardiac (in the heart)• Muscle tissues form organs & organ

systems

Nervous Tissue Communicates

• The neurons and neuroglia

Integumentary System: skin and its derivatives

• Functions:– Physical protection– Regulation of body temperature– Sensory reception– Immune system, Vitamin D

• Skin layers– Epidermis: stratified squamous epithelium; layers progress from living cells to dead (filled

with keratin protein)

• Dermis: tough, permanent connective tissue; has folds and ridges

1. Subcutaneous Layer: anchoring, fat storage

2. Melanin: pigment molecule produced by melanocytes in epidermis

UV radiation: tanning, DNA damage skin cancer

Hair Follicles

• Root & shaft of hairs– Root is living cells, shaft is dead tissue– Keratin on outside, melanin & air space inside

• Nails similar; living cells at cuticle filled with keratin

• Arrector pili muscle – stand on end• Oil glands produce sebum, can plug up

follicle – antibacterial• Sweat glands secrete mixture of water,

salts, acids, urea

– Part of homeostasis system – can modify body temperature, fluid loss

– Homeostasis: dampens fluctuations around a set point – pH, temperature (fever, hypothermia)

– Receptor, control center, and effectors– Biological clock and circadian rhythms