Specialised Connective Tissue

What are Specialised Connective Tissues?

Connective tissue is one of the most abundant and widely distributed tissues in the body. In its various forms, connective tissue has a variety of functions.

One of its types is supportive connective tissues are a type of connective tissue that have special organization and function, which are very crucial in performing their duties, including support, protection, integration, transport, reservoir of energy, and immune response.

Types of Specialised Connective Tissues

The types of specialised connective tissues are cartilage, bone, blood, lymph, and adipose tissue. Each of them has its characteristics and functions.

Cartilage

Cartilage consists of a dense network of collagen fibers and elastic fibers firmly embedded in the ground substance. Cartilage can endure considerably more stress than loose and dense connective tissues. The strength of cartilage is due to its collagen fibers.

Cartilage has few cells and large quantities of extracellular matrix. It differs from other connective tissue in not having nerves or blood vessels in its extracellular matrix. The cells of cartilage are called chondrocytes. Since cartilage has no blood supply, it heals poorly following an injury.

Types of Cartilage

There are three types of cartilage: hyaline cartilage, fibrocartilage, and elastic cartilage.

Structure and Composition

• The cells of cartilage, called chondrocytes occur singly or in groups within spaces called lacunae in the extracellular matrix.

• A covering of dense irregular connective tissue called the perichondrium surrounds the surface of most cartilage and contains blood vessels and nerves and is the source of new cartilage cells.

• Since cartilage has no blood supply, it heals poorly following an injury.

Functions in the Body

• It provides resilience and support in the body.

• It provides smooth surfaces to reduce friction.

• It works in cushioning the bones at the joints.

• It is also a precursor to bone, forming almost the entire embryonic skeleton

Disorders of Cartilage

• Osteoarthritis

• Chondromalacia patellae

Bone

Cartilage, joints, and bones make up the skeletal system. Bones store calcium and phosphorus; house red bone marrow, which produces blood cells; and contain yellow bone marrow, a storage site for triglycerides.

Types of Bone

Bone tissue is classified as either compact or spongy, depending on how its extracellular matrix and cells are organized.

• Compact Bone: About 80% of the skeleton is compact bone. Compact bone tissue contains few spaces and is the strongest form of bone tissue. It forms the outer layer of bones. It provides protection and support and resists the stresses produced by weight and movement.

• Spongy Bone: It is porous and lightweight, always located in the interior of a bone, protected by a covering of compact bone. It is found inside bones, particularly at the ends of long bones.

Bone Remodeling Process

• It is an ongoing process in which bone is resorbed and replaced.

• Osteoblasts are bone-building cells.

• Osteocytes are the main cells in bone tissue. They perform the exchange of nutrients and wastes with the blood.

Common Bone Diseases

• Osteoporosis

• Paget's disease

Blood

Blood, one of the fluid connective tissues, has a liquid extracellular matrix called blood plasma and formed elements. Blood plasma is a pale yellow fluid that consists mostly of water with a wide variety of dissolved substances like nutrients, wastes, enzymes, plasma proteins, hormones, respiratory gases, and ions. Suspended in the blood plasma are formed elements—red blood cells (RBCs), white blood cells (WBCs), and platelets.

Types of Blood Cells

• RBCs or erythrocytes contain haemoglobin and transport oxygen to body cells and remove some carbon dioxide from them.

• WBCs or leukocytes are involved in phagocytosis, immunity, and allergic reactions.

• Platelets or thrombocytes participate in blood clotting.

Functions and Importance

• Transports oxygen, nutrients, and waste products

• Maintains body temperature and pH

• Protects against illness and infection

Blood Types and Transfusions

• Blood group systems (e.g. ABO, Rh)

• Compatibility is important for safe transfusions.

Blood Disorders

• Anemia

• Leukaemia

• Sickle cell anemia

Lymph

Lymph is the extracellular fluid that flows in lymphatic vessels. It is a liquid connective tissue that consists of several types of cells in a clear liquid extracellular matrix that is similar to blood plasma but with much less protein.

Composition

• Semi-transparent fluid containing a high concentration of lymphocytes (WBCs)

• Transports fats and fat-soluble vitamins from the digestive system

Function in Immune System

• Filters pathogens and wastes through lymph nodes.

• Produces and circulates lymphocytes.

Common Lymphatic Disorders

• Lymphedema

• Lymphoma

Adipose Tissue

Adipose tissue has cells derived from adipocytes that are specialized for storage of fats. With weight gain, the amount of adipose tissue increases and new blood vessels form. Thus, an obese person has many more blood vessels than does a lean person.

It is present wherever areolar connective tissue is located, subcutaneous layer deep to skin, around heart and kidneys, yellow bone marrow, padding around joints and behind eyeball in eye socket.

Types of Adipose Tissue

Adipose tissue is categorised into two main types:

• White Adipose Tissue: Most adipose tissue in adults is white adipose tissue. It is mainly composed of large, unilocular adipocytes It stores energy in the form of triglycerides and insulates and cushions internal organs to protect them

• Brown Adipose Tissue: Brown adipose tissue (BAT) is darker due to rich blood supply and numerous mitochondria that participate in aerobic respiration. BAT is widespread in the fetus and infant, adults have only small amounts. It is specialised in heat production through nonshivering thermogenesis.

Disorders Of Adipose Tissue

• Obesity is the result of an energy imbalance where excess energy is stored as fat

• Lipodystrophy is an abnormal distribution of fat.

Functions of Specialized Connective Tissue

Specialised connective tissues have a great deal of functions toward the health and maintenance of the human body.

• Provides structural support and strength to the body.

• Helps in transport of substances like gases, nutrients, wastes, and fluids.

• Plays a role in protection and defense, including immune responses.

• Serves as a site for storage of energy and minerals.

• Maintains homeostasis and cushioning.

Specialized Connective Tissues NEET MCQs (With Answers & Explanations)

Important topic for NEET exam are:

• Bone (Cell types and formation)

• Blood (Components of blood, blood cells, formation, diseases)

• Adipose tissue (Types and their location)

Practice Questions for NEET

Q1. Which type of specialised connective tissue is involved in the maintenance of body shape and the absorption of shock?

1. Skeletal tissue

2. Vascular tissue

3. Reticular tissue

4. Mucoid tissue

Correct answer: 1) Skeletal tissue

Explanation:

Skeletal tissue, specifically bones, is involved in maintaining the shape of the body and absorbing shocks. The rigid and sturdy nature of bones provides structural support, protects internal organs, and helps in locomotion by working in conjunction with muscles and tendons.

Cartilage plays a significant role in shock absorption, bone also contributes to this function especially when considering the structural integrity it provides for the body and in areas like joints.

Hence, the correct answer is option 1) Skeletal tissue.

Q2. Which type of specialised connective tissue forms the endoskeleton of vertebrates?

1. Vascular tissue

2. Reticular tissue

3. Pigmented tissue

4. Skeletal tissue

Correct answer: 4) Skeletal tissue

Explanation:

Skeletal tissue is responsible for forming the endoskeleton which refers to the hard parts of the body in vertebrates. It provides support protection to inner tissues and facilitates locomotion.

Skeletal tissue comes in two primary varieties:

• The tougher and mineralized connective tissue that makes up animals' skeletons is called bone. It helps in the synthesis of blood cells, stores minerals (such as calcium) shields interior organs and offers structural support.

• Cartilage is a more pliable connective tissue that is present in the rib cage, joints, nose, and ears. In some vertebrates, it also contributes to the endoskeleton particularly in the early stages of development before the creation of bones (e.g., in embryos and cartilage-based skeletons in some species like sharks).

Hence, the correct answer is option 4) Skeletal tissue.

Q3. Which specialised connective tissue is involved in transportation within the body?

1. Skeletal tissue

2. Vascular tissue

3. Reticular tissue

4. Mucoid tissue

Correct answer: 2) Vascular tissue

Explanation:

Vascular tissue is responsible for transportation within the body. In animals, it consists of blood vessels that help circulate blood, oxygen, nutrients, etc. while in plants, vascular tissue includes the xylem and phloem which transport water, minerals, and food throughout the plant. In this manner, the vascular tissue helps in the transportation within the body of both plants and animals.

Hence, the correct answer is option 2) Vascular tissue.

Also Read:

• MCQs on Specialised Connective Tissue

• Epithelial Tissue

• Reproduction in Frog

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