Chapter 6

Connective Tissues and

Skeletal System

Objectives

To be familiar with the different connective tissues.

To explain how fat cells grow. To differentiate cartilage from bones. To compare the three kinds of cartilage. To identify the different bones of the

body. To understand how the skeletal system

works.

Connective Tissue

FunctionsConnects,

binds, supports, transports, fights infection and stores materials

CharacteristicsCells are far apart in

arrangementComposed of large

amount of intercellular material also known as matrix

Types of Fibers Composing the Matrix of Connective Tissues Collagenous Elastic Reticular

Collagen Fiber

-Long, wavy and arrange parallel to each other

Collagenous Fiber

Locations: tendons and ligaments

Functions: strong flexible support

ELASTIC Fiber The light pink in this tissue is

smooth muscle.Elastic tissue has numerous

bundles of elastic fibers with interspersed flattened fibroblasts and collagen fibers.

Location: large arteries, bronchial tubes

Function: Elastic fibers can stretch l 1/2 times their length and then recoil. These fibers will provide elasticity to tissues.

RETICULAR FIBER

Reticular tissue supplies the supporting framework for bone marrow and lymphoid hematopoitic (blood cell making) organs.

Locations: spleen, lymph nodes, liver

Function: gives support to soft organs

Classification of Connective Tissue

A. LOOSE CONNECTIVE TISSUE Areolar Reticular Adipose Elastic

1. AREOLAR CONNECTIVE

Locations: beneath the skin and around blood vessels, muscles and nerves

Functions: binds one tissue to another (as skin connects to muscle), protection and nourishment to the organs and structures it binds, and stores "body fluid"

Cells found in the matrix of Areolar Tissue

Fibroblast or Fibrocytes – active in repair and synthesis of fibers and protein.

Macrophage – agent of defense, engulf foreign bodies present in the tissue.

Mast Cells – produce heparin and histamine.

Plasma cell capable of forming antibodies.

Mesenchymal cell- developed into LCT, aka embryonic LCT cell

2. ADIPOSE TISSUE The cells appear empty.

Cells are filled with fat globules (B).

Locations/functions:-- Anywhere there is an empty space in the body fat is stored as a source of energy and may provide insulation.--The kidneys are correctly positioned and cushioned by adipose tissue.

--The eye is cushioned in the orbit by adipose.

Adipose Tissue

is localized to certain depots within the body but may accumulate anywhere.

In men it normally represents some 15-20% of body weight and in women, 20-25% of body weight.

Subcutaneous adipose tissue helps to shape, cushion and insulate the body. It also helps to hold some organs in place.

Almost all adipose tissue in adults is the called yellow adipose tissue

3. RETICULAR TISSUE

4. ELASTIC TISSUE

B. DENSE CONNECTIVE TISSUE

Dense connective tissue has many collagen fibers arranged in bundles and fewer cells. It is stronger and less flexible than loose connective tissue.

Dense irregular connective tissue, as seen in the dermis, has abundant collagen fibers in bundles with no particular orientation. This allows the tissue to handle stress from any direction.

Dense regular connective tissue, as found in tendons and ligaments, is characterized by collagen bundles being oriented in the direction of prolonged maximum stress. Both types of dense connective tissue have a shiny white sometimes translucent appearance in the natural state.

1. Dense Regular connective tissue

Location : Tendon - connects muscle

to bone Ligament – connects bone

to bone Aponeurosis - connect

muscle to muscle Fascia – covers the whole

muscle & hold them together Membrane – covers organs

and cavities

2. Dense Irregular Connective Tissue

Location :Dermis of the skinSheaths of nerves,

muscles and tendons

C. SUPPORTIVE CONNECTIVE TISSUE

Characterized by dense, rigid and firm matrix with cells that are far apart and locked up fluid filled spaces.

1.Cartilage

Cartilage is specialized to bear mechanical stress without permanent distortion.

Most cartilage can be found in areas where shock absorbing or sliding areas for joints.

Cartilage

As was true with the connective tissues proper, these tissues contain various amounts and types of matrix, fibers and cells. Included here are:

Hyaline Cartilage Fibrocartilage Elastic Cartilage

a.HYALINE CARTILAGE

The chondrocytes (A) are located in lacunae (C). The matrix (B) contain collagen fibers that are so fine they are not visible in tissue preparations.

Locations: "C" rings in the trachea, nose, articular ends of bones, fetal skeleton

Function: precursor to bone, support

Hyaline cartilage is found in the fetus where it forms the fetal skeleton that is later ossified and becomes bone

b. ELASTIC CARTILAGE

The chondrocytes (A) are contained in lacunae (C). The matrix (B) contains abundant elastic fibers.These fibers give great flexibility to this tissue.

Locations: ear, auditory canal, epiglottis

Functions: flexible support

Elastic cartilage contains many elastic fibers giving it a yellowish color. it can be found in the auricle of the ear, ear canal, and epiglottis.

c. FIBROCARTILAGE

Locations: pubic symphysis, intervertebral discs

Functions: supports, withstands compression

Fibrocartilage contains a dense network of collagen fibers and is found in the intervertebral discs, attachments of ligaments to cartilagenous surface of bones, and in the pubic symphysis. There is no perichondrium in fibrocartilage

2. BONE

In the center of the osteon is the central canal (A) which hold the blood vessels and a nerve. These canals are surrounded by concentric rings of inorganic matrix, the lamellae (B). Between the lamellae are bone cells, the osteocytes (C) located in lacunae. Nutrients diffuse from cell to cell through the canaliculi (D).

Location: skeleton Function: framework, protection

The skeleton contains 99% of the body's total calcium.

Inorganic portions of the bone matrix represents about 50% of bone by weight. Calcium, phosphorus, magnesium, citrate, potassium, and sodium are found there but the substance that gives bone its hardness is hydroxyapatite made from calcium and phosphate.

Hydoxyapatite crystals are associated with collagen in bone giving it its strength and resistance.

Classification of Bone According to Shape

Long – humerus, femur, tibia, fibula, radius & ulna

Short – clavicle, metacarpals & metatarsals

Flat – scapula, cranial, ribs & pelvic

Irregular – carpal, tarsal, vertebrae & auditory ossicles

Membrane Covering of Bones

Periosteum – outer covering of the bone

Endosteum – lines the cavities and haversian canal

Axial Skeleton:

Skull spinal column sacrum Ribs sternum ear ossicles hyoid bone

Appendicular Skeleton

composed of 126 bones. shoulder girdle:

claviclescapula

arms:humerusulnaradiuscarpalsmetacarpalsphalanges

appendicular skeleton

pelvic girdle:pelvis

legs:femurpatellatibiafibulatarsalsmetatarsalsphalanges

Homology

PECTORAL GIRDLE PECVIC GIRDLEClavicle PubisScapula IliumCoracoid IschiumHumerus FemurRadius -Ulna Tibia-FibulaCarpals TarsalsMetacarpals MetatarsalsPhalanges Phalanges

Exam next meeting….

LOVE, LOVE, LOVE

End of Presentation