Biology 8 Lesson 43: General introduction to the nervous system
1. Summary of theory
1.1. Neuron – structural unit of the nervous system
– The trunk and dendrites form the gray matter in the central nervous system.
Axons are the building blocks of white matter and nerves.
Neurons are composed of:
- Body: star-shaped, containing nucleus.
- An axon has a mielin sheath.
- The ends are synapses – the place of contact between neurons.
+ Body and dendrites → Create gray matter in the central nervous system
+ Axon → Components of white matter and nerves
⇒ Therefore, the neuron is the structural unit of the nervous system
The function of a neuron is:
- Conduction of nerve impulses.
1.2. Parts of the nervous system
The nervous system consists of central and peripheral parts.
– The central organ where the brain and spinal cord are protected in the bony and meningeal cavities: the skull contains the brain; The spinal cord is located in the spinal canal.
– Located outside the central nervous system is the peripheral part, with nerves made up of sensory fibers and motor fibers. In the peripheral part there are also nerve ganglia.
Nervous system: controls skeletal and skeletal muscles. Conscious activity.
– The autonomic nervous system: Regulates the vegetative and reproductive organs. Activity Without Consciousness
2. Illustrated exercise
Why say: Neuron is the structural and functional unit of the nervous system (nervous system)?
– Neuron is the structural unit of nervous tissue in particular and the nervous system in general:
The neuronal body and concentrated dendrites form the gray matter of the cerebral cortex, the cerebellar cortex, the subcortical nuclei, the gray matter of the spinal cord, and the peripheral ganglia (sympathetic and parasympathetic).
The axons of neurons are mostly myelinated, and are aggregated into white matter in the central nervous system (brain, spinal cord) and most nerves in the peripheral nervous system (only postganglionic fibers of sympathetic and parasympathetic nerves of the autonomic nervous system are demyelinated).
Axons branch and end each branch with synaptic synapses (also called synapses) which are the junctions between neurons and the dendrites or trunks of posterior neurons or adjacent to cells of reflex organs. response (muscle, gland).
In synapses, there are vesicles containing chemical mediators synthesized by the neuron itself, which transfer information from the neuron to the next neuron or organ when the neuron receives stimuli from the environment.
– Neurons are also functional units of the nervous system because neurons are capable of excitation and conduction.
Neurons are the main components of a reflex arc, and reflex is a function of the nervous system because all bodily actions are reflexes.
The reflex arc normally consists of afferent neurons in contact with the excitation receptors (receptors) and efferent neurons in contact with the response organs. Afferent and afferent neurons are in contact directly or through an intermediate neuron in the spinal gray matter or cerebral cortex.
3.1. Essay exercises
Question 1: Describe the structure and function of neurons.
Verse 2: Present the parts of the nervous system and their components in the form of a diagram.
Question 3: Distinguish between the functions of the motor nervous system and the autonomic nervous system.
Verse 4: What are the structural features of a typical neuron that you know?
Question 5: What are the parts of the human nervous system? (Can be presented in the form of a diagram).
3.2. Multiple choice exercises
Question 1: What is the function of the nervous system?
A. Control, regulate and coordinate the activities of organs in the body
B. Monitoring activities, informing the brain about the activity of organs in the body
C. Temperature regulation, circulation, digestion
D. Production of nerve cells
Verse 2: What is the structural unit of the nervous system?
B. Blood vessels
D. Nervous tissue
Question 3: What part of the nervous system does the brain belong to?
A. Peripheral Division
B. Central Division
C. An independent division
D. A part of the spinal cord
Verse 4: What part does not appear in the structure of a typical neuron?
A. Rang Vie’s waist
D. Myelin sheath
Question 5: Where in the body is the spinal cord located?
A. Spinal tube
B. Tubes of all kinds of long bones
D. Spine (sacrum)
After completing this lesson, you should:
- Describe the structure and function of neurons.
- Describe the structure of the nervous system.