Connective Tissues

- Supportive tissues

Functions:

1. Connect tissues to one another

2. Storage

3. Transport substances

4. Cushion and insulation

5. Protection

Parts of Connective Tissue: 1. Cells

- scattered, fewer in number

2. matrix

- More matrix than cells

- Varies in consistency

a. liquid (watery)

b. mucoid/ syrupy

c. rubbery/gelatinous

d. tough/mineralized

3. Intercellular fibers elastic

reticular

collagen

ground substance matrix without the fibers

4 Main Types of Connective Tissue:

1. Connective Tissue Proper

2. Cartilages

3. Osseous Tissue

4. Blood/Vascular Tissue

Connective Tissue Proper

1. Connective Tissue Proper

- classified into:

1. Loose Connective Tissue

2. Dense Connective Tissue Dense Regular

Dense Irregular

3. Loose Connective Tissue

with Special Properties Adipose CT

Reticular CT

Mucous CT

Elastic CT

Characteristics of Connective Tissue Proper

- found in the ground substance are the ff. cells

1. fibroblast

- most common cell

- produce fibers

2. macrophages

- engulf bacteria or cellular debris

3. mast cells

- abundant alongside the blood vessels

- produce histamine

- causes dilation of capillaries, constriction of bronchial

smooth muscle, and decreased blood pressure. 4. adipocytes (fat cells)

5. plasma cells - produce antibodies

6. white blood cells

- not found in significant number

- migrate from blood into ct

Fibers

- distinctive protein threads found in the

ground substance

- three common fibers:

1. collagen

2. elastic

3. reticular

3 Types of fibers in CT Proper

1. collagen fiber

- made of collagen

- non-elastic

- resistant to stretching and mechanical pressure

- do not tear easily when pulled lengthwise - provides strength

- white in fresh specimen white fibers

- forms bundles

- resistant to stretching and mechanical pressure

2. yellow/elastic fiber

- exists singly

- made of elastin

- easily stretches

- do not tear easily when pulled lengthwise provides

strength

3. reticular fiber

- made of collagen.

- thin branched network of fibers - Provides support

- silver impregnation technique

- highly branched than collagenous

- forms network

Connective Tissue Proper 1. Loose Connective Tissue

ex. Areolar or Fibro-elastic Connective Tissue

Description:

Gel like matrix with both elastic and non-elastic fibers running though the matrix in many directions

Location:

Dermis of the skin, wraps and cushions visceral organs

Function:

Strength, elasticity and support

Loose Connective Tissue

Specimen:Areolar Connective Tissue

Elastic fiber

Nucleus of the

fibroblast

Collagen fiber

Mast cell

2. Dense Connective Tissue - fibers are compactly arranged

- classified based on arrangement of fibers

a. Dense Regular Connective Tissue

Description:

Consist mainly of collagen fibers arranged in parallel patterns

Location:

tendons, ligament

Function:

provides attachment to other tissues

Dense Regular Connective Tissue

Specimen: Tendon, ligamentum nuchae

tendon with densely packed parallel collagen fibers

fibroblast cell nuclei

b. Dense Irregular Connective Tissue

Description:

consists of collagen fibers randomly arranged and few fibroblast

Location:

perichondrium of cartilage, various organs (liver and kidney), pericardium of

the heart

Function:

provides strength

Dense Irregular Connective Tissue

Specimen: dermis of the skin

dermis of skin (see slide 12)

non-parallel

collagen fibers

Dense Irregular Connective Tissue

thick fibers running in many planes/ directions

E.g. dermis, fibrous capsules around organs

3.Loose Connective Tissue with Special Properties

a. Adipose Tissue

Description:

consists of adipocytes (cells that store fats)

nucleus and cytoplasm peripherally located (signet ring appearance)

Location:

subcutaneous layer of the skin, kidneys, padding around joints

Function:

reduces heat loss through skin

energy reserve

Padding/cushion organs

Loose Connective Tissue with Special Properties

Specimen: Adipose Tissue

nucleus

cell membrane

b. Reticular Tissue

Description:

consist of network of reticular fibers and reticular cells

Location:

stroma (supporting framework) of liver, spleen, lymph nodes and bone marrow

Function:

support of organs

binds smooth muscles together

filters and removes worn-out blood cells in the spleen and microbes in lymph nodes

Reticular Connective Tissue 1000X

spleen

reticular fibers

c. Mucous Connective Tissue

Description:

consists of widely scattered fibroblasts embedded in jellylike ground substance

contains fine collagen fibers

Location:

umbilical cord of fetus

Function:

support

d. Elastic Connective Tissue

Description:

consists of branching elastic fibers

fibroblasts present in spaces between fibers

Location:

lungs, trachea, vocal cords, bronchial tubes

Function:

allows stretching of various organs

Specimen:Cross Section of blood vessel

Cartilages

Cartilages a.Hyaline Cartilage

Description:

bluish white, shiny ground substance

fine collagen fibers (not demonstrated)

many chondrocytes

most abundant type of cartilage

Location:

trachea, larynx, bronchi, anterior ends of ribs, ends of bones

Function:

provides smooth surface for movement of joints,

flexibility and support

- Cartilage cells are named based on their function:

_____blasts cells responsible for forming

the matrix

_____cytes cells responsible for maintaining the matrix

- mature cartilage cells

______clasts cells responsible for remodeling or resorption of

matrix

Hyaline Lacuna

chondrocyte

Perichondrium

Hyaline Cartilage

Specimen: hyaline cartilage of mammal trachea

matrix

Hyaline Cartilage 400X

1 to 4 chondrocytes in lacuna

Chondrocytes in groups cell nest

b. Fibrocartilage

Description:

consists of chondrocytes scattered along small amount of matrix

bundles of collagen fibers within the matrix

no perichondrium

Location:

pubic symphysis, intervertebral disc

Function:

support and fusion

Specimen: Fibrocartilage 400X

chondrocyte in lacuna

collagen fibers

1

2

3

c. Elastic cartilage

Description:

consists of chondrocytes located in a threadlike network of elastic fibers within the matrix

Location:

auricle of the external ear, epiglottis, auditory

(Eustachian) tubes

Function:

gives support and maintains shape

Elastic cartilage

Chondrocyte

Elastic

fibers

Lacuna

Bone/Osseous Tissue

Bone (Osseous Tissue)

Rigid tissue most of skeleton

Contents: cells, fibers, ground substance

Distinguishing feature: inorganic salts in

ground substance

Functions:

1. Supports soft tissues and provides attachment

2. Protects internal organs

3. Stores minerals

4. Hematopoiesis

Chemical Composition of Bone:

Mixture:

Organic (living) components = tenacity,

elasticity, resilience

Inorganic (non- living) components = hardness

and rigidity

General Features: Macroscopic Appearance:

Compact bone tissue

Spongy bone tissue

Color (living): pinkish

blue

Covering: Periosteum (covers

the bone except at

articular surface)

Interior: Marrow Tissue Interior lining: Endosteum

(delicate layer, lines marrow spaces and irregular surfaces of spongy bone)

2 Types of Bone Tissue: 1. Compact bone (external)

- solid

2. Spongy (cancellous)bone

internal

- (lattice work)

Difference: degree of porosity

Osteon or Haversian System: - basic unit of compact bone

4 parts of osteon:

1. Lamellae

- concentric rings of matrix that consists of mineral salts (give hardness to the bones

- fibers

2. Lacunae

- small spaces between lamellae that contain the mature bone cells

3. Canaliculi

- network of minute canals containing the processes of osteocytes

4. central (Haversian) canal

- contains blood vessels and nerves

Bone /Osseous Tissue

Specimen: decalcified bone

osteocyte in lacuna central canal

of osteon

canaliculi

osteocytes

Spongy (cancellous)bone

- lacks osteon

- trabeculae (columns of

bones)

Types of bone cells:

1. Osteoblasts

- bone building cells

- synthesize and secrete collagen needed to build the matrix

2. Osteocytes

- mature bone cells

- matrix

3. Osteoclasts

- endosteum

- bone resorption/ bone restoration

Structural Elements of

Bone Tissue: 1. Cells: Osteocytes = specialized

connective tissue cells

- bone development (formative

cells osteoblasts)

- matrix (become osteocytes)

- irregular in shape, oval

- occupy spaces (lacunae) in

matrix

- minute cell processes found

in canaliculi

2. Bone Matrix

- fibers (collagenous fibers) - united with cementing

substance

- mineral salts, calcium

phosphate, calcium carbonate,

chondroitin sulfate, keratin

sulfate

Blood/Vascular Tissue

Vascular Tissue

- composed of:

a. matrix

- plasma (fluid)

- contains cells, hormones

- yellowish in color

b. cells

- wbc, rbc and platelets

- short lived

c. intercellular fibers

- found in the plasma

- fibrinogen (liquid form)

- fibrin

Functions:

1. Transport and distribution of nutrients

2. Transport and distribution of oxygen

3. Production of antibodies

4. Defense mechanism

5. Blood clotting

Types of cells

1. Red blood cell

- erythrocytes

- hemoglobin

- in mammals during maturation

rbc lose their nuclei

lower vertebrates nucleus is

retained

- most numerous

2. White blood cell

- leukocytes

- nucleated

- body defense

- distinguished based on the staining

reactions and cytoplasmic

granules

Types of wbc according to the number of nucleus and cytoplasmic

granules:

1. Granulocytes

- phagocytosis

- identified base on

a. shape of the nucleus

b. cytoplasmic granules

a. neutrophil

- most numerous

- 3 to 5 lobes

- increase in number during bacterial infection

- pink, lilac granules

- polymorphonuclear wbc (multinucleated)

b. Eosinophil

- 2 lobes

- orange- red granules

- increase in number during

allergies, asthma and

parasitic infection

c. Basophil

- S shaped nucleus

- dark purple to black

granules

2. Agranulocytes

a. Lymphocytes

- produce antibodies

- large nucleus that almost

occupy the entire cell

- increase in number during

viral infection

b. monocyte/mononuclear

wbc

- formed in the liver,

spleen and bone marrow

- phagocytic

- bean shaped nucleus

- migrate in tissue

macrophage

3. Platelets

- thrombocytes

- small, non-nucleated,

colorless, non-motile cells

- blood clotting