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Similar to Nervous system PPT for grade 10 (basic concepts regarding human nervous system)
Nervous system PPT for grade 10 (basic concepts regarding human nervous system)
- 1. NERVOUS SYSTEM (Basic conceptsregarding human nervous system)
- 2. Hafiza Azka Samreen 4thYr DPT- SMC
- 3. The nervous systemin man and in other higher animals is composed of 2 major components : 1. Central nervous system (CNS) 2. Peripheral nervous system ( PNS) Central nervous system consists of brain and spinal cord. Peripheral nervous system consists of nerves that arise from brain and spinal cord (CNS) and spread in differents parts of body. CNS = brain + spinal cord PNS = nerves All these components are made of neurons, it means CNS (brain & spinal cord) and PNS ( nerves) ,all are made of neurons.
- 4. All these componentsare made of neurons.
- 5. Neuron or nervecell • it is the unit of nervous system. • the human nervous system consists of billions of neurons plus supporting cells called neuroglial cells. • Human nervous system = neurons + neuroglial cells. • Neurons are cells ,just like other cells of the body , but they are specialized cells because they transmit information from one part of the body to the other in the form of electrical impulses. In this way they communicate with each other and with other types of body cells. this means that neuron communicates with other neurons in nervous system and neuron also communicates with other cells of body such as heart cells , muscle cells e.t.c This communication occurs through junctions called synapses, we will discuss it later.
- 6. Neurons have 3distinct parts; 1. Cell body (soma) 2. Axon 3. Dendrites • cell body : nucleus and most of the cytoplasm of the neuron is located in its cell body. • Dendrites and axons are actually the cytoplasmic projections from the cell body. • Axons conduct impulses away from the cell body. • Dendrites conduct impulses toward cell body.
- 8. • Schwann cells; special neuroglial cells located at regular intervals along axons. • Myelin sheath; in some neurons schwann cells secrete a fatty layer over axons called myelin sheath. • Nodes of ranvier ; between the areas of myelin on an axon, there are non-myelinated points called nodes of ranvier. Types of neurons: 1. Sensory neurons 2. Interneurons 3. Motorneurons.
- 9. Sensory neurons • theyconduct sensory information from receptors towards CNS. • They have one dendrite and one axon.
- 10. Interneurons • Form brainand spinal cord • They receive information, interpret them and stimulate motor neurons. • They have many dendrites and axons.
- 12. Motor neurons • Carryinformation to muscles or glands ( effectors ) • They have many dendrites but only one axon.
- 16. Nerve • A unionof several axons that are enveloped by a covering made of lipid. • Based on the property of axons , nerves are classified into 3 types : 1. Sensory nerves : contains the axons of sensory neurons only. 2. Motor nerves : contain the axons of motor neurons only. 3. Mixed nerves ; contain the axons of both sensory and motor neurons. A nerve is an enclosed, cable-like bundle of nerve fibres called axons, in the peripheral nervous system. A nerve transmits electrical impulses and is the basic unit of the peripheral nervous system.
- 18. Peripheral nervous system •It is composed of nerves and ganglia • A ganglion is a group of neuron cell bodies in the peripheral nervous system. • In certain parts of body, the cell bodies of many neurons form a group enveloped by a membrane, this is called ganglion. • Ganglia are ovoid structures containing cell bodies of neurons and glial cells supported by connective tissue. Ganglia function like relay stations - one nerve enters and an other exits • A ganglion (pl. ganglia) is a mass of nerve cell bodies found outside of the central nervous system (CNS) along with some glial cells and connective tissue.
- 20. PNS continued…….. • Nervesarise or lead to brain and spinal cord, so they are named as cranial and spinal nerves. • 12 pairs of cranial nerves • 31 pairs of spinal nerves • Some cranial nerves are sensory , some are motor and some are mixed. • All spinal nerves are mixed nerves.
- 23. • Cranial andspinal nerves make 2 pathways 1. Sensory pathway 2. Motor pathway Motor pathway makes 2 systems 1. Somatic nervous system 2. Autonomic nervous system Autonomic nervous system comprises of 1. Sympathetic nervous system (SNS) 2. Parasympathetic nervous system (PANS)
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