Nervous system easy introduction
Download as PPTX, PDF6 likes1,165 views
The document outlines the anatomy and functions of the nervous system, detailing the roles of the central and peripheral systems, types of neurons, and the composition of nervous tissue. It explains the distinctions between gray and white matter, the types and functions of neuroglial cells, and the mechanisms of synapses and reflex arcs. Additionally, it categorizes various reflex types and their anatomical structures.
Nervous system easy introduction
- 1. • General anatomy of nervous system
- 2. Nervous system • Nervous system integrates these sensory information, store information as memory Nervous system receives sensory information •From external environment (temperature, vision, sound etc.) •From body (touch, pressure, pain etc.) Nervous system makes an appropriate response, ex: movement of muscles
- 4. Simple flowchart of nervous system function Skin > touch > nerve (sensory nerve/afferent fibre/ascending tract) Brain nerve(motor nerve/efferent fibres/descending tract) muscle> movement
- 5. CNS : PRINCIPLES ROLES • Integrate and coordinate incoming and outgoing neural signals • Carry out higher mental functions such as thinking and learning
- 6. Division of nervous system • Structurally, • Central nervous system Brain Spinal cord • Peripheral nervous system Cranial nerves, Spinal nerves, Autonomic nerves
- 8. Functional division Somatic nervous system, is the part of nervous system which control voluntary activities Autonomic nervous system, is the part of nervous system concerned with the innervation of involuntary structures, such as the heart, smooth muscle, and glands within the body
- 10. What is the composition of nervous tissue? 1. Neuron ( nerve cell ) 2. Neuroglia Nerve cell body Processes Dendrite Axon
- 11. Nerve cell body Nerve cell processes Dendrite Axon
- 12. Histological feature of neuron nerve cell body A centrally placed spherical, unusually large , euchromatic (pale-staining) nucleus with a prominent nucleolus,
- 13. Nissl body unique feature of neuron Nissl bodies are basophilic granular areas formed by the rER , iron & free ribosomes.
- 14. Golgi complex arranged around the periphery of the nucleus.
- 15. Mitochondria are found through out of the cell body, dendrites, and axons. They are spherical or rod shaped.
- 16. Axon hillock : it is the area of cell body which is free of large cytoplasmic organelles. It is a landmark to distinguish between axons and dendrites in both light & TEM microscopes.
- 17. • Dendrites are receptor processes that receive stimuli from other neurons or from the external environment • Axon are effector processes that transmit stimuli to other neurons or effector cells
- 18. What is gray matter and white matter?
- 19. Grey matter Nerve cell body Neuroglia Blood vessel White matter Nerve processes Neuroglia Blood vessels Neuroglia Blood vessels
- 20. • Gray matter: Neuron cell bodies Neuroglial cells Blood vessels • White matter: Processes of neuron Neuroglial cells Blood vessels
- 21. Location of gray & white matter in the CNS • Cerebrum and cerebellum , • Outer gray matter • Inner white matter • Spinal cord, • outer part white matter • Inner gray matter
- 25. Classification of neuron According to the polarity
- 26. According to function Sensory neuron Motor neuron
- 27. Neuroglia • The neuron of the central nervous system are supported by several varieties of non excitable cells, which together are called neuroglia. • They are smaller than the neuron • Number of them 5-10 times greater than the neuron
- 28. There are four types of neuroglial cells in CNS & two types in PNS: CNS 1. Astrocytes (a) fibrous (b) protoplasmic 2. Oligodendrocytes 3. Microglia 4. Ependyma • PNS 1. Schwann cells 2. Satellite cells.
- 30. Protoplasmic Astrocytes Fibrous Astrocytes
- 32. Ependyma
- 33. Schwann cells: It have the same function as oligodendrocytes but are located around axons in the peripheral NS. Axon
- 34. Functions of neuroglia Name of the neuroglia Functions Astrocytes Formation of blood brain barrier Oligodendrocyte Myelination of nerve fibers in the CNS Ependymal cells secrete, circulate and absorbed CSF Microglia Phagocytic function in inflamed brain (They are inactive in normal brain) Schwann cells Myelination of nerve fibers in the PNS
- 35. Development of neuroglia Name of the neuroglia Functions Astrocytes Neuroectoderm Oligodendrocyte Neuroectoderm Ependymal cells Neuroectoderm Microglia Mesodermal in origin Schwann cells Neural crest
- 36. What is myelin sheath? • Axon of neuron is covered by sheaths which are modified cell membranes of schwann cells in PNS and oligodendrocytes in CNS
- 37. Schwann cells Axon Schwann cells undergo spiraling around the axon
- 39. Myelination in the CNS by oligodendrocyte
- 40. Function of myelination • It acts as an insulator • Helps in impulse conduction
- 41. Ganglia a collection of nerve cell bodies out side the CNS 1. sensory ganglia of spinal nerves (posterior root ganglia) and cranial nerves 2. autonomic ganglia
- 43. Nucleus: a collection of nerve cell bodies of neuron in the CNS is called nucleus Example: Dorsal nucleus of vagus nucleus ambiguous, nucleus of tractus solitarius
- 46. What is synapse? • The synapse is the specialised junctions between two or more adjacent neurons.
- 47. How impulse go from one neuron to another ?
- 49. What are the types of synapses? According to the location of synapse in the post synaptic neurons
- 50. • How nervous system is worked ?
- 53. Reflex arc • A reflex may be define as an involuntary response to a stimulus. It depends on the integrity of the reflex arc . A reflex arc consists of the following anatomical structures: Location 1) a receptor organ Skin, muscle, or tendon 2) an afferent neuron Posterior root ganglion 3) an effector neuron Example: Lower motor neuron located in the ventral horn of spinal cord 4) an effector organ Example: Skeletal muscle
- 54. Structural organization of reflex may be two types •Monosynaptic reflex Incoming axons of the unipolar primary sensory neurons synapse directly on a motor neuron. Example: tendon jerks •Polysynaptic reflex In these reflex one or more interneurons, excitatory or inhibitory, intervene between sensory and motor neurons.
- 56. Types of reflex • Reflex may be divided into 4 groups: 1) superficial (or skin and mucous membrane) reflexes Corneal reflexes, gag reflexes 2) deep (or myotatic) reflexes Jaw jerk, knee jerk 3) visceral ( or organic) reflexes Pupillary reflex 4) pathological (or abnormal) reflexes Ankle clonus, Babinski’s sign