CBSE Class 9 Science Notes Chapter 6 Tissues

Meristematic tissues are crucial components of plant growth and development. These tissues are characterized by their rapid cell division, which leads to the formation of new cells and allows the plant to grow. Meristematic tissues are primarily found at the tips of roots and shoots, as well as in regions called meristems. These regions are responsible for the continuous growth of the plant throughout its life cycle.

Permanent tissues

Permanent tissues, on the other hand, are derived from meristematic tissues and serve various structural and functional roles in the plant. Unlike meristematic tissues, permanent tissues consist of cells that have undergone differentiation and specialization to perform specific functions. These tissues can be further classified into two main types: simple permanent tissues and complex permanent tissues. Simple permanent tissues are composed of similar types of cells that perform a specific function. For example, parenchyma tissue is made up of living cells and serves functions such as photosynthesis, storage, and secretion. Collenchyma tissue provides support to growing plant parts and is composed of elongated cells with thickened cell walls. Complex permanent tissues, on the other hand, consist of different types of cells that work together to perform specialized functions. Xylem and phloem are examples of complex permanent tissues. Xylem is responsible for transporting water and minerals from the roots to the rest of the plant, while phloem transports organic nutrients, such as sugars, from the leaves to other parts of the plant.

Differentiation

Differentiation is the process by which meristematic tissues undergo changes to become specialized permanent tissues. This process involves the activation of specific genes within the cells, leading to the development of distinct cell types with unique structures and functions.

Apical meristem

Apical meristems are meristematic tissues located at the tips of roots and shoots. These tissues are responsible for the primary growth of the plant, contributing to increases in height and length. Apical meristems continuously produce new cells that differentiate into various types of permanent tissues, allowing the plant to grow and develop. meristematic tissues play a vital role in plant growth and development by continuously producing new cells, while permanent tissues contribute to the plant's structural integrity and functionality through specialized cell types and functions. Differentiation and the presence of apical meristems further enhance the plant's ability to adapt and thrive in its environment.

Lateral meristem

Nervous tissue is a specialized type of animal tissue that forms the nervous system, which includes the brain, spinal cord, and peripheral nerves. It plays a fundamental role in coordinating and regulating bodily functions, as well as processing sensory information, generating responses, and maintaining homeostasis. The main components of nervous tissue are neurons and neuroglial cells (or glial cells), which work together to transmit electrical signals throughout the body and provide support and protection to neurons. Neurons: Neurons, also known as nerve cells, are the functional units of the nervous system. They are specialized for transmitting electrical impulses, or action potentials, over long distances. Neurons consist of three main parts: a. Cell Body (Soma): The cell body contains the nucleus and other organelles essential for the neuron's metabolic activities. b. Axon: The axon is a long, slender projection that extends from the cell body and conducts electrical impulses away from the cell body to other neurons, muscles, or glands. c. Axon Terminals: At the end of the axon, specialized structures called axon terminals or synaptic terminals transmit signals to other neurons or target cells through synapses, which are junctions between neurons. Neurons can be classified based on their structure and function into sensory neurons, motor neurons, and interneurons. Sensory neurons transmit sensory information from sensory receptors (such as those for touch, temperature, and pain) to the central nervous system (CNS), while motor neurons convey signals from the CNS to muscles and glands to initiate responses. Interneurons, or association neurons, integrate and process information within the CNS. Neuroglial Cells (Glial Cells): Neuroglial cells, or glial cells, are non-neuronal cells that provide structural support, insulation, and nourishment to neurons. They also play critical roles in maintaining the chemical environment of neurons and modulating synaptic transmission. Glial cells include several types, such as astrocytes, oligodendrocytes, microglia, and Schwann cells, each with distinct functions and properties. Overall, nervous tissue is essential for regulating body functions, processing sensory input, coordinating motor responses, and enabling complex cognitive processes such as learning and memory. Dysfunction or damage to nervous tissue can lead to various neurological disorders and impairments in sensory, motor, and cognitive functions.

Benefits of CBSE Class 9 Science Notes Chapter 6 Tissues

• Simplified Explanations: The notes are written in simple language, making complex biological concepts easier to understand for students.
• Organized Structure: The information is presented in a well-organized manner, making it easier for students to follow and comprehend the key points.
• Quick Revision: The concise nature of the notes allows students to quickly revise the entire chapter before exams or assessments, saving time and effort.
• Exam Preparation: The notes are designed to align with the CBSE curriculum, making them an excellent resource for exam preparation, helping students score well in their science exams.
• Concept Clarity: By providing clear explanations and examples, the notes help students develop a strong foundation of understanding in the topic of tissues, which is important for further studies in biology.

Chapter-Wise CBSE Class 9 Science Notes
Chapter 1 - Matter in Our Surroundings
Chapter 2 - Is Matter Around Us Pure
Chapter 3 - Atoms and Molecules
Chapter 4 - Structure of The Atom
Chapter 5 - The Fundamental Unit of Life
Chapter 6 - Tissues
Chapter 7 - Diversity in Living Organisms
Chapter 8 - Motion
Chapter 9 - Force and Laws of Motion
Chapter 10 - Gravitation
Chapter 11 - Work and Energy
Chapter 12 - Sound
Chapter 13 - Why Do We Fall ill
Chapter 14 - Natural Resources
Chapter 15 - Improvement in Food Resources