Student-made hand-out... General Histology and Histotechnique Lecture; 2012-2013; 1st sem; Midterm handout Credit to the original owner of the pictures used in this pdf document

1. General Histology and Histotechnique (1st semester; 2012-2013)
SUPPORTIVE TISSUE
(Specialized Connective Tissue)
I. Cartilages
- From chondrocytes
- Fibers: Collagen and Elastic
- Chondroitin Sulfate – for resilience
 Ability to return to its
original shape.
- No blood vessels or nerves except in
perichondrium.
 A membrane of dense irregular
connective tissue that surrounds
most of the cartilages.
- Can endure considerable stress
 Due to the presence of fibers.
Types of Cartilage:
1. Hyaline Cartilage
- Most abundant type of cartilage
- Consists of bluish-white-ground substances with
collagen fibers.
- Surrounded by perichondrium
- Chondrocytes within Lacunae.
- Weakest type
- Chondrocytes forms in the perichondrium move
out of the cell and into the tissue where they
are scattered.
Ex. Trachea
Functions:
- It provides smooth surfaces for the movement 2. Fibrocartilage
of joints. - Consists of chondrocytes that are scattered
- Provides support and flexibility. - Strongest type
Location: End of long bones, anterior ends of ribs,  Combines strength and rigidity
nose part of larynx, trachea, bronchi, bronchial - No perichondrium
tubes, and embryonic tissues. - Symphysis – point where hipbones joint
anteriorly
- Menisci – the cartilage pads of the knee
- Periosteum – contains collagen
Ex. Bone Marrow
Function: For support and Fusion

2. General Histology and Histotechnique (1st semester; 2012-2013)
Location: Pubic symphysis, Intervertebral discs,
Menisci of knee, and portions of Tendons that
insert into cartilage.
Growth and repair of cartilage:
- Grow slowly
- Relatively inactive tissue
- When injured or inflamed, repair proceeds
slowly since it is avascular.
Two basic patterns of cartilage growth:
1. Interstitial growth
- Increases rapidly
 Due to the existing division of
chondrocytes
- Expansion from within
 Due to the existing chondrocytes that
is continuously dividing.
- Occurs while the cartilage is young and pliable.
3. Elastic Cartilage  From Childhood to adolescence.
- Consists of chondrocytes located in the thread-
like collagen fibers. 2. Appositional growth
- With perichondrium - Activity of cells in the inner chondrogenic layer
Functions: of the perichondrium leads to growth.
- Gives support and maintain shape - Starts later that interstitial growth and
- Provide strength and elasticity continues through adolescence.
Location: External ear, auditory tubes, and lid on - Fibroblast divide, some differentiate into
top of Larynx. chondroblasts
- Chondroblasts surround themselves with matrix
and become chondrocytes.
Steps:
1. Ridges in Periosteum create groove for
periosteal blood vessel.

3. General Histology and Histotechnique (1st semester; 2012-2013)
 Crystallization and
tissue hardening by
mineral deposits.
2. Periosteal ridges fuse, forming an endosteum-
lined tunnel.
II. Bone or Osseus Tissues
- 65% of bone weight in calcium hydroxyapatite
(Calcium phosphate), calcium hydroxide,
calcium carbonate.
(65% - Calcium phosphate only)
- Contains Tropocollagen
 Subunits giving the
bone elasticity and
fracture resistance.
- Highly vascular and well innervated
3. Osteoblasts in endosteum build new concentric
- Contains lymph channels
lamellae inward toward center of tunner,
- Functions in mineral storage and blood cell
forming a new osteon.
production.
Bone
- Connective tissue components:
1. Periosteum
- Covering the bone
- Tough sheet of dense irregular connective
tissue surrounding the bone surface
2. Endosteum
- Inner part; Membrane that lines the space
within the bone that stores the yellow bone
4. Bone grows outward as osteoblasts in marrow.
Periosteum build new circumferential lamellae.
Osteon formation repeats as new periosteal 3. Red bone marrow
ridges fold over blood vessels. - Produces RBC, WBC’s, Platelets
- Osteoblast initiates calcification or - Process: Hematopoietic/hemopoiesis
mineralization.

4. General Histology and Histotechnique (1st semester; 2012-2013)
4. Yellow bone marrow
- Consists primarily of adipocytes
- Infused scattered blood cells.
Functions of bones:
1. Support
- Framework for soft tissue
- Provide attachment pint of the bones
2. Protection 2. Osteoblasts
- Protect many internal organs of the body - Bone building cell
Ex. Skull – brain; ribcages – lungs, heart - Secrete collagen fibers and other substances
needed to build matrix of bone.
3. Assistance in movement - Initiates calcification
- During muscle contraction, it will pull the bone
in order to assists movement. 3. Osteocytes
- Maintains bone tissue, mature cell
4. Mineral homeostasis - Principal cells of bone tissues
- Bone stores minerals (Ca2PO4, Ca2C03) Function:
Maintain the daily cellular activities of the bone
5. Blood cell production tissue.
- From red bone marrow  Exchange of
nutrients and waste
6. Triglyceride storage in the blood.
- Yellow bone marrow to adipocytes
Four types of cells in bone tissue:
1. Osteogenic cells
- Develops into osteoblasts; desired
mesenchyma.
- Unspecified stem cells derived from
mesenchyme
- Only bone cell to undergo cell division
Location: Inner portion of the Periosteum in
endosteum, and in canals without bone that
contain blood vessels. 4. Osteoclasts
- Contains a powerful lysosomal enzymes that
digest protein and mineral components of
underlying bones
- Functions in resorption, the breakdown of bone
matrix.
Ruffled border – deeply folded plasma membrane.

5. General Histology and Histotechnique (1st semester; 2012-2013)
Huge cell – derived from fusion of 50 monocytes - It is where articulation with another bone
contain in the endosteum. forms.
- Reduces friction and absorbs shocks at freely
removable joints.
5. Periosteum
- Outer covering
- Tough covering of dense tissues
- Contains the bone forming cells, osteocytes,
that in enables the bone to grow in diameter
but not in length
Functions:
- Protects the bone
- Assists in fracture repair
- Helps nourish bone tissue
- Serves as attachment point for ligaments and
tendons.
6. Medullary cavity/ Marrow cavity
- A space within diaphysis that contains the fatty-
yellow bone marrow
Structure of bone macroscopic anatomy 7. Endosteum
- Membrane containing bone forming cells and
1. Diaphysis line the medullary cavity.
- The bone’s body or shaft which is a long-
cylindrical main portion of the body.
2. Epiphysis
- Proximal and Distal epiphysis – ends of bones.
3. Metaphysis
- Epiphyseal plate
- Part of the bone where diaphysis joins the
epiphysis and diaphysis.
- Includes epiphyseal line
- A point where cartilage is replaced by bone
- Hyaline cartilage that allows the diaphysis to
grow in length but not in width.
Types of bone tissues:
I. Compact bone tissue
4. Articular
- Osteon or haversian system:
- Thin-layer hyaline cartilage covering the
epiphysis.
1. Concentric Lamellae

6. General Histology and Histotechnique (1st semester; 2012-2013)
- Concentric ring of matrix that consists of
minerals with CaPO4, CaOH, CaCO3; more on
Calcium and Phosphate.
- Contains fiber-collagen – for strength
- Haversian – 20-40
2. Lacunae (Lacuna)
- Small spaces between lamellae that contains
the osteocytes.
3. Canaliculi
- Small canals that project from lacuna.
 Provide route or blood for the
nutrients and oxygen
4. Haversian canal
- Volmann’s/Perforating canal
- Contain 1 or 2 blood vessels/nerves
- Connected with one another and communicate
with the free surfaces and bone marrow via the
perforating canal.
 For movement of
nutrients system.
5. Interstitial System
- Contains in the interstitial system/Lamellae
 Angular fragments of lamellar bone
 Made up of the interstitial lamellae.
- Fragment of older osteons that have been
partially destroyed during bone rebuilding.
6. Cement lines
II. Spongy bone tissues
- Does not contain true osteon.
- Consist of trabeculae
 Lamellae that are arranged in an
irregular columns of bones.
 Function: Reduces weight
Ossification – process of bone formation
- Spaces between lamellae are filled with red
bone marrow

7. General Histology and Histotechnique (1st semester; 2012-2013)
- It is light which reduces the overall weight of
bone.
Bone formation:
Ossification
Two kinds:
1. Intramembranous ossification
- Formation of bone directly on within fibrous
connective tissue membranes
- Formed by condensed mesenchymal cells
- Form directly from mesenchyma without first 4. Development of Periosteum
going through a cartilage stage.  Fibrous collagen
- layer – Osteogenic layer
Steps:  Layer under
1. Development of ossification center Periosteum.
2. Calcification
 Osteocytes need to deposit mineral salts
so that it will harden matrix. 2. Endochondral ossification
- The formation of bone within hyaline cartilage
- Mesenchymal cells are transformed into
chondroblasts, which initially produce a hyaline
cartilage model of the bone
- Subsequently, osteoblasts gradually replace the
cartilage with bone.
Steps:
3. Formation of trabeculae 1. Development of cartilage model.
 Fused with one - Consists of hyaline cartilage and perichondrium
another that create
the spongy bone. 2. Growth of cartilage model
- Blood vessels – grow into spaces of spongy Two growths:
- Development period: Spongy and compact a. Interstitial growth
bone tissue. - Continuous cell division/growth from within.
b. Apositional growth

8. General Histology and Histotechnique (1st semester; 2012-2013)
- Addition of more matrix by new chondroblasts
(grow in diameter).
5. Development of secondary ossification
center
- Secondary ossification
3. Development of primary ossification center - As blood move upward into ossification plate.
- Nutrient artery stimulates Osteogenic cells to
differentiate onto osteoblasts
- Include the formation of primary ossification
center.
 A region where bone tissue replaced
most of the cartilages.
6. Formation of articular cartilage and
epiphyseal plate.
- Hyaline cartilage that covers the
epiphyseal/epiphysis become the articular
cartilage but haversian canal is present in
between the epiphysis and diaphysis forming
4. Development of medullary (marrow) cavity. the epiphysis.
- it is done by osteoclast that breaks the newly  Responsible for
formed spongy bone trabeculae lengthwise growth.
- Cavity filled with Blood vessels

9. General Histology and Histotechnique (1st semester; 2012-2013)