Summarize the following text to main points and sub-points and make detailed explain for them:

 
Assistant Lecturer-Sarah A. Tulfah                                                                          Human Biology 
                        
 
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 Tissues 
Types of connective tissue: A- Loose connective tissue: There are many types of this 
tissue:  
1- Areolar connective tissue: Is a loose general packing tissue. There are elastic 
and non-elastic fibers running through this tissue, giving it strength as well as 
flexibility. It also contains cells such as macrophages and other cells that produce 
antibodies and anti-coagulants. This tissue is found all over the body, such as: 
beneath the skin (subcutaneous), supporting organs, lying under membranes and 
within the walls of the blood vessels. 
 
2-Mucoid connective tissue:  
The most prominent component of this tissue is a jelly like ground substance rich 
in hyaluronic acid, with scattered star-shaped fibroblasts, some delicate collagen 
fibers and some rounded cells. This kind of tissue is found in the umbilical cord 
and the vitreous of the eyeball. 
 
 
 
 
 
 
 
Assistant Lecturer-Sarah A. Tulfah                                                                          Human Biology 
                        
 
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3. Adipose connective tissue: 
It is fatty tissue, has cells that are able to store fat in their cytoplasm area, pushing 
the nucleus to one side. This tissue is found beneath the skin, around the heart and 
kidneys as well as acting as an insulation pad and energy storage tissue which 
support and protect many parts of the body. 
 
4. Reticular connective tissue:  
Is a network tissue found within such structures as the liver, spleen and lymph nodes. 
It forms a support tissue for many organs; it also has a defensive function because it 
contains phagocytic cells that destroy invading foreign particles. 
 
 
 
Assistant Lecturer-Sarah A. Tulfah                                                                          Human Biology 
                        
 
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5. Mesenchymal connective tissue:  
The most part of this tissue is mesenchymal cells which have the ability to 
transform itself to other types of the connective tissue cells; there are no fibers 
from any type found in this type of tissues. It is found in the embryo. 
 
 
B-Dense connective tissue:  
I-Regular connective tissue:  
1-White fibrous or (collagen) connective tissue:  
It is white in appearance runs in bundles throughout many organs and structures, 
and it is non-elastic. It is making up the composition of tendons (muscle to bone 
connector), in the ligaments (bone to bone connector) and within the movable 
scalp. 
 
 
 
 
 
 
Assistant Lecturer-Sarah A. Tulfah                                                                          Human Biology 
                        
 
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2-Elastic fibrous connective tissue:  
Is yellow in appearance and has much brunched fibers. It is running through the 
organs that are capable of changing shape. This type is found in the vocal cords, lung 
tissue, the walls of the arteries, the windpipe (trachea) and it also makes up part of 
the intervertebral discs located between the vertebrae of the backbone.  
II-Irregular connective tissue:  
This tissue is found in the keratinized skin consisting great part of dermis. This tissue 
resembles the areolar connective tissue but the thickness of the white fiber bundles 
more in this tissue. 
 
 
Specialized Connective tissue  
The Cartilage  
The chondrocytes or cartilage cells are embedded within the cartilage matrix. The 
spaces they occupy called lacunae (singular = lacuna). A layer of dense irregular 
connective tissue called perichondrium encapsulates the cartilage. Cartilaginous 
tissue is non-vascular; thus, all nutrients need to diffuse through the matrix to reach 
the chondrocytes. This is a factor contributing to the very slow healing of 
cartilaginous tissues. The three main types of cartilage tissue are hyaline cartilage, 
fibrocartilage, and elastic cartilage.  
 
 
Assistant Lecturer-Sarah A. Tulfah                                                                          Human Biology 
                        
 
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1. Hyaline cartilage:  
Is the most common type of cartilage in the body. It is a glossy, bluish-white flexible 
material which has a gel-like background or (matrix) in which there are cell spaces 
(lacunae) containing cartilage producing cells (chondroblast), which will form 
chondrocytes in the growing cartilage matrix. It consists of short and dispersed 
collagen fibers and contains large amounts of proteoglycans. Under the microscope, 
tissue samples appear clear. The surface of hyaline cartilage is smooth. 
Both strong and flexible is found in the flexible parts of the rib cage, nose, trachea, 
bronchi and covers bones where they meet (ends of bones) to form movable joints. 
It forms the template of the embryonic skeleton before bone formation. A plate of 
hyaline cartilage at the ends of bone allows continued growth until adulthood. 
 
 
 
 
 
 
 
 
 
 
Assistant Lecturer-Sarah A. Tulfah                                                                          Human Biology 
                        
 
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2. Fibrocartilage:  
Is a tough flexible tissue because it has thick bundles of collagen fibers dispersed 
through its matrix. It is found in the discs between the vertebra (intervertebral discs) 
as well as in the symphysis pubis (front of pubic bones). 
 
 
 
 
 
 
 
 
 
3. Elastic-cartilage:  
Is much more flexible because it contains yellow elastic fibers as well as collagen 
and proteoglycans. This tissue provides support as well as elasticity. It is located in 
the pinna (external ear), the larynx and in the nasal septum. 
 
 
 
Assistant Lecturer-Sarah A. Tulfah                                                                          Human Biology 
                        
 
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The Bone  
Bone is a tough and more brittle tissue than cartilage. It is the hardest connective 
tissue, formed in the body by a process known as ossification. Bone provides 
protection to internal organs and supports the body. The bones of an adult are formed 
upon the cartilage and fibrous framework in the embryo. This process beings at about 
week 6 of embryonic life and it continues to adult life.  
The areas that are designed to become bone are invaded by bone-building cells called 
osteoblasts. Osteoblasts are the active bone forming cells. They are producing the 
organic part of the extracellular matrix. The mature bone cells, osteocytes, are 
located within lacunae and the spaces between the cells contain the salts calcium 
phosphate and 8  
 
calcium carbonate which causes the hardness of bone. The whole bone surface is 
covered by a membrane called the periosteum.  
The rigid extracellular matrix of the bone contains mostly collagen fibers embedded 
in a mineralized ground substance containing hydroxyapatite, a form of calcium 
phosphate. The bone matrix consists of organic and inorganic components; both 
components of the matrix contribute to the unusual properties of bone. Without 
collagen, bones would be brittle and break easily. Without mineral crystals, bones 
would flex and provide little support. Bone is a highly vascularized tissue. Unlike 
cartilage, bone tissue can recover from injuries in a relatively short time. There are 
two types of bone: 
1. Dense or compact bone:  
It is located in the outer surface of the bone. The histology of a cross sectional view 
of compact bone shows a typical arrangement of osteocytes in concentric circles 
around a central canal. This structural unit of compact bone is called the osteon or 
Haversian system. 
 
 
 
 
Assistant Lecturer-Sarah A. Tulfah                                                                          Human Biology 
                        
 
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2. Spongy (or cancellous) bone:  
This bone has no Haversian system. It looks like a sponge under the microscope 
and contains empty spaces between trabeculae. It is lighter than the compact bone 
and found in the interior of bones and at the end of long bones, within the spaces 
the red marrow is found at the ends of bone or yellow marrow in the shaft area. 
 
 
 
 
 
 
Assistant Lecturer-Sarah A. Tulfah                                                                          Human Biology 
                        
 
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The Blood 
1. Plasma (Liquid Matrix – 55-60% of blood volume) 
• Pale yellow fluid (~90% water). 
• Contains dissolved salts (0.85% salt concentration, similar to 
seawater). 
Proteins (7-8% of plasma): 
• 
Albumin (maintains osmotic pressure). 
• 
Globulins (immune functions, transport). 
• 
Fibrinogen (blood clotting). 
Other dissolved substances (1%): 
• 
Nutrients (glucose, amino acids, lipid

Summary :