Nervous System

Classification of Nervous System

1. Functional Classification
2. Anatomical Classification

1.Functional Classification

graph TD
    X{Nervous System} ==>|Voluntary function like moving arm,speaking| 1a(Somatic Nervous Sysyem);
    X ==>|Involunatry like maintaining BP,HR, Size of lens etc…| 1b(Autonomic Nervous System);
    1b ==>|In Fight or Flight situation| 1b1[Sympathetic Nervous System];
    1b ==>|Rest and digest Situation| 1b2[Para-sympathetic Nervous System];

2.Anatomical Classification

graph TD
    X{NErvous System} ==>|Brain and Spinal cord | 1[Cental Nervous System];
    X ==>|Others | 2[Peripheral Nervous System];

Cells of Nervous System

1. Neurons = functional unit .No mitosis
2. Glial cells = Supporting cell ,+ mitosis

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Histology of Neuron

Nucleus

• Highly active ==> Euchromatin
• Ribosomes are Actively Produced ==> Basophilic Nucleolus

Cytoplasm

• Ribosomes Actively secreting Neuro-Transmittor and they are spend => Ribosomes in RER forming Nissl bodies ==> BAsophilic of ribosomes

Classification of Neurons

1. Shape
2. Function

Classification of Neurons by Shape

graph LR
    X{Neurons} ==>|multiple Dendrites and One Axons| A[Multipolar-Neuron];
    X ==>|No dendrites and only 2 Axon| B[Bipolar];
    X ==>|No dentrites , 2 Axons But looks like one Axon| C[Pseudo-Unipolar Neuron];

Classification of Neurons by Function

graph LR
    X{Neuron by Function} ==>|Pseudo-Unipolar looking Neurons| A[Sensory neuron eg:Skin]
    X ==>|Bipolar Neuron| B[Special sense like Vision,hearing];
    X ==>|Multipolar Neuron| C[Motor Neuron];