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; 2012-2-13)
CONNECTIVE TISSUE 2. Macrophages/Histocytes
Characteristics: - Developed from monocytes (WBC)
- Have intercellular spaces - Irregular shape
- Cells scattered in matrix
- Wide variety of cells most abundant Function:
- Vascular - To engulf those bacteria – cellular debris;
- From mesoderm phagocytosis
- Lie below basement membrane Two types:
Functions: a. Fixed Macrophage
1. Binds together, supports and strengthens other body - it resides in a particular tissue only
tissues Ex.: Alveolar macrophages in the lungs; spleen
2. Protects and insulates internal organs.
3. Compartmentalizes structures such as skeletal b. Wandering macrophage
muscles. - Roamed the tissues and then gather at sites of
4. The major transport system within the body. infection/inflammation.
5. The major site of stored energy reserves; for fat cells.
3. Plasma Cells
Connective Tissue: Embryonic origin - Small and round/irregular shape
- blast - Developed from lymphocytes
- cytes – mature cells; form the connective tissues. - Secretes antibodies
 Proteins that attacking on foreign
Two basic elements: substances in the body.
1. Cell  Important in Immune System.
2. Matrix Location: GIT, Mammary gland
Types of Cells 4. Mast Cells
- Abundant alongside of Blood vessels that supply
connective tissue.
- Produce Histamine
 A chemical that dilates small blood
vessels
 Especially during the reaction in the
injury.
5. Adipocytes (fat cells)
- May form small clusters or aggregates in loose
connective tissue.
- Store lipids and form adipose tissue.
Functions: It Protects, insulates and cushions organs of
1. Fibroblasts the body.
- Large-flat-spindle shaped cells with branching
processes. 6. WBC
- Present in all - Not found insignificant numbers in connective
- Most numerous tissues
Function: - When there is a significant numbers of WBC –
- To secrete the proteins needed for fiber synthesis. Abnormality
- Components for intercellular matrix. - Increase number in response to allergic condition
during parasitic invasion.

2. General Histology and Histotechnique (1st semester; 2012-2-13)
Neutrophil – Increase number at site of infection. - Jelly-like substance that provide support and
adhesiveness in cartilages, bones, skin, and blood
7. Chondrocytes vessels.
- Mature cells that form cartilages.
Dermatan sulfate - found in skin, tendon, Blood vessels,
8. Osteocytes Heart bulbs
- form the bones Keratan sulfate – Found in bone, cartilage, cornea of
the eye.
9. Hematopoietic cells
- Form the Blood cells 3. Adhesion Protein
- Responsible in linking components of ground
10. Undifferentiated mesenchyma substances to each other and to the surfaces.
- Potential to differentiated into adult cell types
Fibronectin – principal adhesion protein of connective
Connective tissue MATRIX tissue
Ex.:
Matrix - It binds halogen, fibers, and ground substances and
- Maybe fluid, semi-fluid, gelatinous, fibrous, or cross-linked them together.
calcified - It attaches cells to ground substances
Function: To prevent tissue cells from touching one
another. B. Fibers
Consists of: - Strengthen and support connective tissues
Types:
A. Ground Substance
- Highly hydrated gel which the cells and fibers of 1. Collagen Fibers
connective tissue are embedded “colla” – glue
- Intercellular substances - Appear as white fiber
Made up of: - Most abundant connective fibers
- Contain a protein substance known as collagen.
1. Hyaluronic Acid - For flexibility at a High Tensile Strength
- Viscous
- Slippery substances 5 types of collagen fibers:
Function:
- To bind cells together Types Location Function
1. Type 1 Skin, bone tendon, Accounts for 90% of the
- To lubricate
ligament, dentine, total body collagen;
- It helps maintain the shape of eye ball sclera of the eye, organ provide resistance to
capsules force tension and
Hyaluronidase stretch.
2. Type 2 Cartilage (hyaline and Provide shape &
- It breaks apart the hyaluronic acid, and causes the elastic) notochord, resistance to
ground substance to become watery. invertebral disc. deformation
Location: 3. Type 3 Uterus, liver, spleen, Provide structural
WBC – produces hyaluronidase to move connective kidneys and lungs, support and elasticity
smooth muscles, blood
tissue. vessels and fetal skin.
- Produce by sperm cell – to fully penetrate the eggs 4. Type 4 Basal lamina of Provide support and
during fertilization epithelial and filtration barrier
endothelial cells,
- Produce by bacteria for them to spread in kidney
connective tissues 5. Type 5 Basal lamina of smooth Provide support.
and skeletal muscle
2. Chondroitin Sulfate cells, glial cells,
placental epithelium

3. General Histology and Histotechnique (1st semester; 2012-2-13)
- It forms a network around fat cells, nerve
cells/fiber, skeletal & muscle cells.
- Forms the Stroma
 Meaning “bed/covering”
 Supporting framework of many soft
organs.
- Helps form the basement membrane
Location: boundary of C.T. and epithelial, around blood
vessels, nerves, hematopoietic tissues such as bone
marrows, liver, spleen
Classification of Connective Tissue
2. Elastic fibers
- Known a Yellow fiber I. Embryonic
- Smaller diameter than in collagen - Present in embryos and fetus
- Branched to joined together to form network within
a tissue a. Mesenchyme
- Protein – Elastin - Exclusively found in embryo
 Surrounded by glycoprotein – Fibrillin - This tissue were all types of connective tissue arise
– essential to the stability of elastic - Composed of irregular cell – mesenchymal cell
fibers. - Contains a semifluid ground substance
- Contains a delicate reticular fiber
Function: Location: found under skin and along developing bones
- For strength and stability of embryo, in adult connective tissues especially blood
Location: Skin, Blood vessels (walls), lung tissues vessels.
2 types:
1. Stretched
2. Relaxed
b. Mucous / Warton’s jelly
- Consists of a widely scattered fibroblast
- Viscous ground substance and jelly-like collagen
fibers
3. Reticular fibers Location: Umbilical cord
- Consists of collagen and protein of glycoprotein Function: For support
- Produced by fibroblasts
- Thinnest and form branching network
Functions:
- Provide support and strength
- Provide support to the walls of Blood vessels

4. General Histology and Histotechnique (1st semester; 2012-2-13)
II. Mature
1. Loose
- Fibers are loosely woven
a. Areolar
- One which is widely distributed in the body
- Forms the subcutaneous layer
 Layer of a tissue that attaches the skin to the
underlying tissues and organs.
- Most common connective tissues in all
invertebrates.
- One of the component of Basement membrane
- Consists of Macrophages, mast cells, Fibroblasts
Function: b. Adipose
- Separates muscles - Adipocytes; fat cells
- Derived from fibroblast
- Good insulator (reduced heat loss)
- Widespread in fetus & infants
- Only small amount in adult
Function: for storage of triglycerides
Location: found I subcutaneous layer deep to skin,
around heart and kidneys, yellow marrow of long
bones, padding around joints and behind eyeball in eye
socket.

5. General Histology and Histotechnique (1st semester; 2012-2-13)
2. Dense
- More numerous thicker and denser fibers
- With few cells
a. Dense regular connective tissue
- Matrix-Shiny white
- Bundles of collagen fibers
Function: Provide strong attachment between various
structures.
Location: Tendons (muscle to bone); Ligaments (bone to
bone); Aponeurosis (muscle to muscle/ muscle to bone)
c. Reticular
- Consists of reticular fibers/reticular cells
- Forms stroma of organs
- Binds together smooth muscle tissue cells
- Contains collagen, elastic & reticular
- Cells – fibroblast, macrophage, plasma cells,
adipocyte, mast cells
Location: Stroma (supporting framework) of liver,
spleen, lymph nodes; portion of bone marrow; reticular
lamina of basement membrane, around blood vessels
and muscle, subcutaneous layer of skin, lamina propria
of mucous, nerves.
b. Dense irregular connective tissue
- Collagen fiber (randomly arranged)
- Few fibroblast
Location: Fascia (tissue beneath skin and around
muscles and other organs); reticular region of dermis of
skin, periosteum of bone, perichondrium of cartilage,
joint capsules, membrane capsules around various
organs (kidneys, liver, testes, lymph nodes),
pericardium of the heart and heart valves.

6. General Histology and Histotechnique (1st semester; 2012-2-13)
c. Elastic connective Tissue
- Branching elastic fiber
- Cell - fibroblast
- Allows stretching of various organs
Location: Lung tissue, walls of elastic arteries, trachea,
bronchial tubes, true vocal cords, suspensor ligament of
penis, and ligaments between vertebrae.