Animal Tissues
NCERT Class 9 • Science • Chapter "Tissues"
Animal Tissues
Animal tissues are grouped into four kinds: epithelial, connective, muscular and nervous. Because animals move and their body has to cope with that movement, animal tissues carry a much larger share of supporting, contracting and signalling work than plant tissues do.
Epithelial and Connective Tissue
- Epithelial tissue covers the body surface and lines internal organs and cavities, forming a protective barrier.
- Squamous epithelium is a thin flat layer that allows exchange, as in the lining of blood vessels and lung alveoli.
- Cuboidal epithelium lines kidney tubules and glands; columnar epithelium lines the intestine and absorbs food.
- Ciliated epithelium has hair like structures that move mucus, as in the respiratory tract.
- Connective tissue links and supports other tissues and always has cells spread in a matrix.
- Blood is a fluid connective tissue with plasma as the matrix and red cells, white cells and platelets suspended in it.
- Bone is a hard connective tissue; cartilage is softer and found in the nose, ear and joints; ligament joins bone to bone and tendon joins muscle to bone.
- Areolar tissue fills spaces inside organs and adipose tissue stores fat and insulates the body.
Muscular and Nervous Tissue
- Muscular tissue brings about movement through contraction, and it is of three kinds.
- Striated or skeletal muscle is attached to bones, appears striped, and is voluntary, meaning it works under our control.
- Smooth or unstriated muscle lines the stomach, intestine and blood vessels and is involuntary.
- Cardiac muscle is found only in the heart, is striated but involuntary, and contracts rhythmically without tiring throughout life.
- Nervous tissue is made of neurons and conducts electrical impulses rapidly across the body.
- A neuron has a cell body, dendrites that receive signals and a long axon that carries the signal onward.
- Nervous tissue makes up the brain, the spinal cord and the nerves, and it coordinates every response of the body.
| Tissue | Main Function | Example |
|---|---|---|
| Epithelial | Covering and protection | Skin lining, intestine lining |
| Connective | Support and linking | Blood, bone, cartilage |
| Muscular | Movement by contraction | Skeletal, smooth, cardiac |
| Nervous | Conducting impulses | Brain, spinal cord, nerves |
Neuron — the structural and functional unit of nervous tissue, made of a cell body, dendrites and an axon.
Exam me kaise aata hai
- Which muscle is found only in the heart — cardiac muscle
- Which tissue joins muscle to bone — tendon
- Which tissue joins bone to bone — ligament
- Blood is which kind of tissue — fluid connective tissue
UPSC/State PSC ke liye
- Cardiac muscle is unique in being striated yet involuntary, and in contracting rhythmically for a lifetime without fatigue.
- Blood is classed as connective tissue because it has cells suspended in a matrix, even though it looks nothing like bone or cartilage.
Yahan confuse hote hain
✗ Tendon and ligament are the same | Tendon joins muscle to bone; ligament joins bone to bone | ✓
✗ All striated muscle is voluntary | Cardiac muscle is striated but involuntary | ✓
✗ Blood is not a tissue | Blood is a fluid connective tissue | ✓
Ek nazar me
- Four animal tissues: epithelial, connective, muscular and nervous.
- Epithelium covers and lines; connective tissue has cells in a matrix.
- Skeletal muscle is voluntary, smooth and cardiac are involuntary.
- Neurons carry impulses and make up the brain, spinal cord and nerves.
Ab practice karein
Cell aur tissues se har exam me seedhe factual questions bante hain. ExamAtlas ke mock test se abhi practice karein.