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๐ฌ Think about it
Blood flows to every corner of your body, and bones hold you up from head to toe. Both connect and support parts of the body, yet one is a liquid and the other is hard. How can both be the same kind of tissue? Let us find out.
What is connective tissue?
- A connective tissue connects and supports other tissues.
- Both blood and bone are connective tissues.
- They differ because of their matrix.
- The matrix is watery in blood but hard and rigid in bone.
Connective Tissues
Connective tissue
↓
Blood
Fluid matrix; carries substances.
Bone
Hard matrix; gives support.
Cartilage
Soft matrix; cushions joints.
Tendon & ligament
Join muscle-bone and bone-bone.
In this Activity, we will recall everyday experiences about blood and match them with observations to understand blood and its components.
Procedure
Recall the everyday experiences in the first column of Table 3.3. Write your observations and questions in your notebook. Compare your observations with those given in Table 3.3.
Table 3.3 — Your experiences, observations and questions from daily life
| Experiences | Observations | Questions |
|---|---|---|
| When you get a small cut on your skin | Red blood oozes out from the cut. A clot is formed after some time. | What causes blood to clot? |
| When you get a skin infection | The area turns red and perhaps slightly swollen. You may have a fever. | Why does the area swell and turn red? |
| When you exercise or run | You breathe faster. Your face may turn red. | Why does breathing become faster? |
Explanation
1. The red colour of blood is due to haemoglobin, an iron-rich protein in the Red Blood Cells (RBCs). RBCs live for about 4 months and are replaced regularly.
2. Platelets help in blood clotting at the site of injury.
3. During exercise, muscles need more oxygen, so breathing becomes faster and blood flow increases (the face appears red).
4. White Blood Cells (WBCs) collect at infected areas, causing pus and inflammation (redness and swelling).
2. Platelets help in blood clotting at the site of injury.
3. During exercise, muscles need more oxygen, so breathing becomes faster and blood flow increases (the face appears red).
4. White Blood Cells (WBCs) collect at infected areas, causing pus and inflammation (redness and swelling).
โ Summary
- Recall blood experiences.
- Match with observations.
- RBCs, WBCs, platelets do jobs.
- Blood is connective tissue.
What does blood contain and do?
- Blood carries nutrients, gases and hormones around the body.
- RBCs hold haemoglobin and carry oxygen.
- Platelets help in clotting at an injury.
- WBCs fight infection at infected areas.
In this Activity, we will perform simple body actions and match each to the connective tissue responsible for it.
Procedure
Perform the actions given in Table 3.4. Record your experiences and compare them with the experiences given in Table 3.4. Study their functions and identify the connective tissues.
Table 3.4 — Connective tissues
| Action | Experience | Function | Identified connective tissue |
|---|---|---|---|
| Touch your elbow gently | A hard and rigid structure | Gives strength, support and protection | Bone |
| Press and fold your ear or gently press your nose | A soft and flexible structure that retains shape again | Provides flexibility and cushions the ends of bones for shock absorption | Cartilage |
| Touch your forearm muscles and wiggle your fingers | Feel movement in the forearm even though fingers are far away | Connects muscle to bone, and thus brings about movement | Tendon |
| Sit on a chair and move your leg upwards till your knee allows | The joint does not go beyond a limit | Connects bone to bone, gives stability, limits movement and prevents dislocation | Ligament |
โ Summary
- Do simple body actions.
- Feel hard, soft, pulling structures.
- Match each to a tissue.
- Find four connective tissues.
What do bone and cartilage do?
- Bone has a rigid matrix with calcium and phosphorus.
- This gives bone strength and rigidity.
- Cartilage has a soft, jelly-like matrix.
- Cartilage provides flexibility and cushioning.
What do tendons and ligaments do?
- Tendons connect muscles to bones.
- This connection helps bring about movement.
- Ligaments connect bone to bone.
- Ligaments give stability and prevent excessive movement.
Important Points
- Connective tissue connects and supports other tissues.
- Blood, bone, cartilage, tendon and ligament are connective tissues.
- Tendons join muscle to bone; ligaments join bone to bone.
โ Test Yourself
-
What is the job of connective tissue?
View Answer
To connect and support other tissues. -
Why is blood a connective tissue if it is a liquid?
View Answer
It connects body parts by carrying substances; it just has a watery matrix. -
What does a tendon connect?
View Answer
Muscle to bone. -
What does a ligament connect?
View Answer
Bone to bone.
Important Definitions
- Connective tissue — a tissue that connects and supports other tissues.
- Matrix — the material between cells of a connective tissue (watery in blood, hard in bone).
- Tendon — connective tissue joining muscle to bone.
- Ligament — connective tissue joining bone to bone.
