Chemistry easy learnig

07/09/2025

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سوال نمبر 25کہوٹہ ریسرچ لیبارٹریز کا نیا نام کیا ہے ؟جواب:کہوٹہ ریسرچ لیبارٹریز کا نیا نام ڈاکٹر اے کیو خان ریسرچ لیبارٹریز ہے۔WHAT IS THE NEW NAME OF KAHUTA...

30/04/2021

B- Spinal Cord
The spinal cord is in fact a tubular bundle of nerves. It starts from brain stem and extends to lower back. Like brain, spinal cord is also covered by meninges. The vertebral column surrounds and protects spinal cord.
The outer region of spinal cord is made of white matter (containing myelinated axons). The central region is butterfly shaped that surrounds the central canal. It is made of grey matter (containing neuron cell bodies).
31 pairs of spinal nerves arise along spinal cord. These are “mixed” nerves because each contains axons of both sensory and motor neurons.
1312. Coordination and Control
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At the point where a spinal nerve arises from spinal cord, there are two roots of spinal nerve.
Both roots unite and form one mixed spinal nerve (Fig. 12.4).
• The dorsal root contains sensory axons and a ganglion where
cell bodies are located.
• The ventral root contains axons of motor neurons.
Spinal cord is the continuation of medulla oblongata.
Figure 12.4: Spinal Cord and Spinal Nerves
Spinal cord performs two main functions:
1. It serves as a link between body parts and brain. Spinal cord transmits nerve impulses from
body parts to brain and from brain to body parts.
2. Spinal cord also acts as a coordinator, responsible for some simple reflexes.
Peripheral Nervous System
The peripheral nervous system (PNS) is composed of nerves and ganglia. Ganglia are the clusters
of neuron cell bodies outside CNS. Nerves arise or lead to brain and spinal cord. So they are named
as cranial and spinal nerves.
1412. Coordination and Control
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Spinal cord is roughly 40cm long and about as wide as your
thumb for most of its length.
Humans have 12 pairs of cranial nerves and 31 pairs of spinal nerves. Some cranial nerves are
sensory, some are motor and some are mixed. On the other hand, all spinal nerves are mixed
nerves.
The cranial and spinal nerves make two pathways i.e. sensory pathway (conducting impulses
from receptors to CNS) and motor

27/04/2021

Chemistry - IX 2 Unit 1: Fundamentals of Chemistry
Introduction The knowledge that provides understanding of this world and how it works, is
science. The branch of science which deals with the composition, structure, properties and reactions of matter is called chemistry. It deals with every aspect of our life. The development of science and technology has provided us a lot of facilities in
daily life. Imagine the role and importance of petrochemical products, medicines and drugs, soap, detergents, paper, plastics, paints and pigments, insecticides, pesticides which all are fruit of the efforts of chemists. The development of chemical industry has also generated toxic wastes, contaminated water and polluted air around us. On the other hand, chemistry also provides knowledge and techniques to improve our health and environment and to explore and to conserve the natural resources. In this chapter, we will study about different branches of chemistry, basic
definitions and concepts of chemistry.
1.1 BRANCHES OF CHEMISTRY It is a fact that we live in the world of chemicals. We all depend upon different
living organisms which require water, oxygen or carbon dioxide for their survival. Today chemistry has a wide scope in all aspects of life and is serving the humanity day and night. Chemistry is divided into following main branches: physical chemistry, organic chemistry, inorganic chemistry, biochemistry, industrial chemistry, nuclear chemistry, environmental chemistry and analytical chemistry.
1.1.1 Physical Chemistry Physical Chemistry is defined as the branch of chemistry that deals with the
relationship between the composition and physical properties of matter along with the changes in them. The properties such as structure of atoms or formation of molecules behavior of gases, liquids and solids and the study of the effect of temperature or radiation on matter are studied under this branch.
1.1.2 Organic Chemistry Organic Chemistry is the study of covalent compounds of

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14/08/2020

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06/05/2020

Easy way to learn chemistry periodic table group no 2 alkaline Earth metal

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Learn chemistry periodic table