1. The nervous system

2. The nervous system Definition
It is a body system containing a network of cells called neurons that control the actions of an animal and transmit signals between different parts of its body
احد اجهزة الجسم ويتكون من شبكة من الخلايا التي تسيطر على جسم الحيوان وتنقل الاشارات بين خلايا الجسم

3. nervous system

4. Structural Classification of the Nervous System
-- The nervous system consists of two parts, مكون من جزئين (المركزي والطرفي)central and peripheral.
-- The central nervous system الجهاز العصبي المركزيcontains the brain المخand spinal cordالحبل الشوكي .
-- The peripheral nervous system consists of sensory neurons, clusters of neurons called gangliaالعقد, and nerves الاعصاب .

6. Functions of the Nervous System
1. Sensory input – gathering information
To monitor changes occurring inside and outside the body (changes = stimuli)
2. Integration
to interpret sensory input and decide if action is needed.
3. Motor output
A response to stimuli
The response activates muscles or glands

7. Nervous Tissue: Type of cells
The nervous system contains two main categories or types of cells: neurons and glial cells.
1. Neurons
-- Cells specialized to transmit messages
-- It has a cell bodyجسم الخلية , dendritesالزوائد الشجرية , and an axonمحور الخلية.

8. Neuron Anatomy Dendrites Cell body Axon Nucleus
-- Dendrites conduct impulses توصل الاشاراتtoward the cell bodyنحو جسم الخلية, while axons conduct impulses away بعيداً from the cell body.
Dendrites
Cell body
Nucleus
Axon

9. Functional Classification of Neurons
(A) Sensory neurons حسية
Carry impulsesتحمل الاشارات from the sensory receptors مستقبلات حسية
(B) Motor neurons حركية
Carry impulsesتحمل الاشارات from the central nervous system
(C) Interneurons البينية
They connect sensory and motor neurons.

10. Sensory neurons
Carries impulses from receptors e.g pain receptors in skin to the CNS( brain or spinal cord)

11. Carries impulses from sensory nerves to motor nerves.
Interneuron
Carries impulses from sensory nerves to motor nerves.

12. Motor neuron
Carries impulses from CNS to muscle to bring about movement or gland to bring about secretion of hormone

13. 2. Glial cells خلايا الغراء العصبي
-- They are non-neuronal cells that provide support and nutrition

14. Neuroglia vs. Neurons Neuroglia divide. Neurons do not.
Most brain tumors involve the Neuroglia cells, not the neurons.