Biology 8 Lesson 48: Somatic nervous system
1. Summary of theory
1.1. Vegetative reflex arc
– Path of nerve impulses in the motor reflex arc: The receptor that receives the stimulus will send nerve impulses along the afferent nerve through the dorsal horn to the nerve center for analysis and then send out nerve impulses through the roots. anteriorly along the efferent nerve to the muscular response organ.
– Path of nerve impulses in the motor reflex arc: The intestine contracts and sends out nerve impulses along the afferent nerve to the lateral horn of the spinal cord for analysis and then sends out the nerve impulse to the sympathetic ganglia and along the nerve. Centrifugal nerve response to the stimulus reduces intestinal motility.
– Reflex arc regulating cardiac activity (vegetative reflex): From the pressure receptor, the sensory nerve impulses are sent along the sensory fibers to the nerve center in the brainstem (medullary medulla), analyzed and then released. The vagus nerve travels through the preganglionic fibers to the parasympathetic ganglia through the postganglionic fibers to the heart, reducing heart rate.
The vegetative reflex arc has:
Central: gray matter in the lateral horns of the spinal cord and brainstem.
There are nerve ganglia.
→ Control the operation of internal organs.
1.2. Structure of the autonomic nervous system
The nervous system includes:
- Central: brain, spinal cord
- Peripheral: nerves and ganglia
The autonomic nervous system is divided into:
- Sympathetic nervous system
- Parasympathetic nervous system
1.3. Functions of the autonomic nervous system
– Although the two sub-systems sympathetic and parasympathetic have opposing effects, thanks to the coordination and regulation of the activities of the two sub-systems on the activities of the internal organs, the unity of the body’s activities is ensured. able and adaptive to changes in the environment.
2. Illustrated exercise
Lesson 1: The pupil dilates to let more light into the eye and constricts to limit light entering the eye. When suddenly changing from good to bright, which nervous system controls the activity of the pupil?
A. Sympathetic Nervous System
B. Parasympathetic Nervous System
C. Both subsystems of the autonomic nervous system
D. Motor nervous system.
- Choose the answer: NO
- Explanation: The pupil in the dark is dilated, in the morning the pupil constricts to limit light entering the eye. The parasympathetic subsystem regulates this activity.
Lesson 2: Why is there no appetite when angry?
A. Due to decreased activity of the digestive system
B. Because the brain forgets
C. Because when angry, cells increase metabolism, taking energy from the fat layer
D. Because the intestines are more active
- Choose the answer: A
- Explanation: Anger is controlled by the sympathetic subsystem, the sympathetic system will reduce the activity of the digestive system, causing no appetite.
Lesson 3: Why stay up late at night or go to the toilet?
Midnight according to circadian time is when the body rests, the parasympathetic subsystem is active, causing the bladder to shrink, so it is often difficult to go to the toilet.
3.1. Essay exercises
Question 1: Describe the structural and functional similarities and differences between the sympathetic and parasympathetic nervous systems of the autonomic nervous system.
Verse 2: Describe the reflexes that regulate the activity of the heart and vascular system in the following cases:
Question 3: Compare the structure and function of the motor nervous system with the autonomic nervous system in the nervous system?
Verse 4: Distinguish between motor reflex arc and vegetative reflex arc?
3.2. Multiple choice exercises
Question 1: The autonomic nervous system consists of how many subsystems?
Verse 2: Which structural component is not present in the reflex arc that regulates cardiac activity?
A. Sensory yarn
B. Pressure receptor
D. The vagus cord
Question 3: The phenomenon of decreased intestinal motility is caused by which nervous system division?
A. Sympathetic subsystem
B. Parasympathetic subsystem
C. Central subsystem
D. Peripheral subsystem
Verse 4: What is the central nervous system of the sympathetic subsystem?
A. Gray nucleus in the lateral horn of the spinal cord
B. Chain of nodes located near the spine
C. Gray nucleus in the brainstem
D. Nerve ganglion
Question 5: What function is performed by the autonomic nervous system?
A. Understanding spoken and written language
B. Memory formation
D. Create a dream
After completing this lesson, you should know the following requirements:
- Distinguish vegetative reflexes from motor reflexes
- Distinguish between the sympathetic and parasympathetic parts of the autonomic nervous system in terms of structure and function.
- Practice observing and analyzing video channels