II. Connective Tissue  Supports and protects body parts  Manufactures blood cells Composed of widely scattered cells. Lie within nonliving material 2 types of cells 1. P roduces and maintains intercellular material which are composed of 3 types of protein fibers A. collagenous B. elastic C. reticular 2. protects tissue from infection

3 Types of Protein Fibers Collagenous fibers (collagen) Elastic fibers (elastin) Reticular fibers (reticulum)

1. Collagenous Fibers (Collagen)  M ost abundant (10% total body weight)  T hick wave like strands  F lexible but tensile (resists stretching)  F ound in tendons (connect muscle to bones)  A lso used by body for tissue repair *scar tissue, binds skin tightly together

2. Elastic Fibers (Elastin)   N ot as strong as collagen  E lasticity and extensibility * Pinch skin and it returns to its normal shape

3. Reticular Fibers (Reticulum)  R esists physical stress Not abundant in connective tissue

4 Types of Connective Tissue Based on density of proteins) 1. Connective tissue proper 2. Cartilage 3. Bone 4. Blood-forming tissue and blood

1. Connective Tissue Proper  E ach type has a cell called fibroblast which produces the intercellular  material  3 types based on the fibroblast a. Loose connective tissue b. A dipose tissue c. Dense connective tissue

a. Loose Connective Tissue  Most widespread  S tructural anchor to body parts  B etween skin and muscles  S urfaces of organs Known as areolar tissue (referring to little area)

b. Adipose Tissue   F at cells called adipocytes  F at stored as triglycerides Provides insulation and padding between organs

c. Dense Connective Tissue  T ightly packed protein fibers  R egular or irregular  R egular are fibers parallel to each other like tendons and ligaments (connect bones to bones) irregular are fibers not parallel like deep layers of skin (dermis) and external wrap around bones and cartilage.

2. Cartilage  Harder than connective tissue proper  Protein fibers in thickened gel-like ground substance called matrix  Matrix maintained by “gristle” cells called chondrocytes that lie in small chambers called lacunae which get nourishment from the perichondrium (dense connective tissue)  types of cartilage a.Hyaline b.Elastic c.Fibrocartilage

a. Hyaline   B luish white  R espiratory tract  E nds of bones at movable joints Ends of ribs

b. Elastic   Y ellowish  F ramework of ears  E nd of nose Epiglottis (small opening to larynx)

c. Fibrocartilage  Thick collagenous fibers  Joints like knees Between intervertebral discs (padded joints)

QUESTIONS Packet pp.59-60

3. Bone  Intercellular material is mineral salts and collagenous fibers  Hardest and most durable of all tissue. Dense matrix Composed of matrix of osteocytes embedded in lacunae (chambers). Nourished by periosteum which is a membrane surrounding the bone. Canaliculi are channels through which nutrients reach bone cells

2 Types of Bone a. C ompact bone b. Spongy bone

b. Spongy Bone   Not dense, have spaces called red marrow (blood forming tissue)  Form thin plates called spicules Interior of bones Packet p.61

4. a.) Blood-Forming Tissue and b.) Blood a. B lood-forming tissue  anufactures cellular components of blood  Contains 3 components i. S tem cells (produce blood cells) ii. Y oung blood cells (newly formed) iii. Protein (lacks collagen, so is softest connective tissue)  2 types i. Red marrow  H ematopoietic tissue (initiates production of all cells) ii. Lymphoid tissue  I n lymph nodes  I n tonsils  S pleen, thymus  I it is maturation site of 2 types of W.B.C. 1. Lymphocytes 2. Monocytes

b. Blood  The WBC, RBC and platelets are called formed elements and are surrounded by a fluid matrix called plasma  F ormed elements means the fibers of the matrix are dissolved proteins Carries respiratory gases, nutrients and wastes

Packet p. 62 Packet pages should now be done Quiz on all notes through blood