The nervous system consists of central nerve and peripheral nerve. The central nerve includes the brain and spinal cord, and the peripheral nerve consists of sensory organs, motor organs and internal organs.
First, neurons and their functions
The nervous system is composed of nerve cells, namely neurons, which are composed of cell bodies, dendrites and axons.
Dendrites receive stimuli (convert matter/chemical energy into nerve impulses), transmit pulses to cell bodies, and axons transmit nerve impulses to other neurons. The contact point between the former neuron and the latter neuron is called synapse, and the neurotransmitter changes and is transmitted to the next neuron.
Neurons are divided into sensory neurons, motor neurons and intermediate neurons; Also known as afferent, efferent and communicating neurons.
Second, the peripheral nervous system and its function
(1) 12 pairs of cranial nerves and 3 1 pairs of spinal nerves.
12 cranial nerve has nerves emanating from the brain, including olfactory nerve, optic nerve, auditory nerve, oculomotor nerve, trochlear nerve, abductor nerve, accessory nerve (pharynx and shoulder movement), hypoglossal nerve, trigeminal nerve (sensation and movement), facial nerve, glossopharyngeal nerve and vagus nerve (skills of regulating viscera, blood vessels and glands).
3 1 the spinal nerve originates from the intervertebral foramen on both sides of the spine and is divided into two branches, which are responsible for the sensation and movement of the relevant parts of the body below the neck. Including 8 pairs of cervical nerves, 12 pairs of thoracic nerves, 5 pairs of lumbar nerves, 5 pairs of sacral nerves and 1 pair of caudal nerves.
(2) Somatic nervous system and autonomic nervous system
Peripheral nerves can be divided into somatic nerves and autonomic nervous system in function.
Trunk nerve is the nerve that reaches all sensory organs and motor organs, and the central nervous system dominates sensory organs and motor organs through them.
Autonomic nerve is the nerve that dominates internal organs, which comes from cranial nerve and spinal nerve and is distributed in internal organs such as heart, blood vessels, respiratory organs, gastrointestinal smooth muscle and glands. (autonomic nerve)
Third, the central nervous system and its function
The central nervous system is a place where a large number of nerve cells are concentrated, including the spinal cord and brain. The brain consists of brain stem, diencephalon, cerebellum and telencephalon.
(1) spinal cord
It is thinner and thinner from top to bottom, divided into front, back and middle sections. The anterior segment is mainly motor neurons, the middle segment is mainly autonomic neurons, and the posterior segment is mainly sensory neurons.
The spinal cord is well divided and the middle is approximately circular. The gray matter of spinal cord is H-shaped around the canal, and the white matter outside the gray matter is composed of nerve fibers of spinal nerves.
The spinal cord is the lowest part, which can not only transmit information, but also complete a simple reflex arc.
(2) Brain stem
The brain stem is located at the junction of cranial cavity and spinal cord, including medulla oblongata, pons and midbrain.
The medulla oblongata, which is close to the spinal cord, is the upward and downward channel of nerve fibers. Pontine, above the medulla oblongata and before the cerebellum, is the ascending and descending channel of nerve fibers; The midbrain is above the pons, which is also the ascending and descending channel, and the center of pupil reflex and eye movement.
(3) diencephalon
The diencephalon is located above the brain stem and is covered by two hemispheres. It consists of four parts: thalamus, upper thalamus, hypothalamus and subthalamus.
Thalamus: the center of all senses (except smell)
Upper thalamus: involved in the regulation of sense of smell and some hormones.
Hypothalamus: the nerve center of the autonomic nervous system under the cerebral cortex, which regulates the activities of the visceral system.
Subthalamic: Adjust muscle tension so that exercise can be carried out normally.
(4) Cerebellum
The cerebellum is located behind the pons and is connected with them through three pairs of cerebellar feet. The structure of cerebellum is opposite to that of spinal cord, with white matter in the deep layer and gray matter in the surface layer.
Its function is to maintain body balance, adjust muscle tension and realize voluntary movement and voluntary movement.
Fourth, the structure and function of the brain
Telencephalon: The brain covering the brain stem, diencephalon and cerebellum. The middle fissure is called longitudinal fissure, and the transverse fiber bundle at the bottom is called corpus callosum. The outer layer of the brain is a dense nerve cell body called gray matter or cerebral cortex, and the inner layer is myelinated nerve fibers called white matter; The gray matter nuclei in white matter are called basal nuclei.
Fifth, the asymmetry of the function of the two hemispheres of the brain.
The functions of the two sides of the brain are asymmetric, and the left side is language, concept formation, logical reasoning and mathematical operation; On the right are space perception, thinking in images, music, artistic activities, expression and recognition of emotions, etc. The corpus callosum is responsible for connecting two brain functions.
The endocrine system consists of pituitary gland, adrenal gland, thyroid gland, thymus gland, pancreas and gonads. Dominated by the autonomic nervous system, glands dominate each other.
I. pituitary gland
Location: Located in the lower part of thalamus, it is controlled by thalamus and consists of anterior pituitary and posterior pituitary.
Function:
The posterior pituitary gland controls urine and blood pressure, and affects delivery and milk secretion;
The anterior pituitary gland directly affects the growth rate and duration, and affects the activities of other glands.
Second, the adrenal gland
Location: Located in the upper part of kidney, it consists of adrenal cortex and adrenal medulla.
Function:
Adrenal cortex secretes adrenal steroids, and its secretion is regulated by pituitary gland, which is directly related to people's emotional behavior.
Adrenal medulla secretes adrenaline and norepinephrine, which is similar to the phenomenon caused by sympathetic nervous system activity in autonomic nervous system.
Third, the thyroid gland
Location: Located at both sides of the lower end of trachea.
Function: Secrete thyroxine, promote metabolism and collective development;
Hyperactivity, sharp increase in appetite but no weight gain, excessive sensitivity, nervousness and excitability; Lack of energy, listlessness, memory loss, and easy fatigue.
Four. gonad
Location: Men are testicles and women are ovaries.
Function: Testis secretes testosterone to stimulate sperm production; Ovary secretes estrogen and progesterone to control ovulation, pregnancy and menstrual cycle respectively. Gonadas also promote the development of secondary sexual characteristics.
First, several basic concepts of Baslov's theory
Excitement and inhibition
It holds that the basic process of nerve activity is excitement and inhibition. From rest to activity and vice versa.
(2) reflection, reflex arc and feedback
Reflex: A regular response of an organism to internal and external environmental stimuli, involving the nervous system.
Reflex arc: the nerve pathway to realize reflex activity, which consists of five parts: receptor, afferent nerve, reflex center, efferent nerve and effector.
Feedback: refers to the result of reflex activity, which is fed back to nerve center. Make the brain get action information in time, so as to effectively regulate the follow-up process.
(3) Unconditional reflex and conditioned reflex
Unconditional reflex: refers to the reflex born without learning;
Conditioned reflex: refers to the reflection formed by individuals on the basis of unconditional reflex through imitation and learning.
Secondly, several basic laws of higher nervous activity discovered by Pavlov.
(A) inhibition of conditioned reflex
External inhibition: the appearance of additional stimuli stops the reflex, such as the sudden ringing of the mobile phone during meditation;
Overlimit inhibition protection: long-term stimulation, or strong stimulation, will damage nerve cells;
Fading inhibition: conditioned reflex will not be strengthened, but will be inhibited;
Differentiation inhibition: At the initial stage of conditioned reflex formation, the interference similar to stimulus will form a generalization phenomenon, and conditioned reflex can be 40 watts or 80 watts. If only one stimulus is strengthened, the response of other stimuli will gradually disappear, which is differentiation inhibition.
(2) Diffusion and concentration
Diffusion and concentration are the basic forms of neural process movement in cerebral cortex. Generalization is diffusion, and reflection differentiation is concentration. In the early stage of riding, the body is all nervous, and the proficiency in the later stage is concentrated, and only a few nerves are paying attention.
(3) Mutual induction
Mutual induction: the progress of one neural process can cause the appearance of another neural process;
It can be divided into positive induction and negative induction. One is excitement, and the other is peripheral inhibition, which is negative induction. A kind of inhibition, peripheral excitement, is a positive induction.
It can also be divided into simultaneous induction and subsequent induction, that is, a new feeling is triggered at the same time, and a new feeling appears after removal.
(4) Dynamic stereotype
Several conditioned reflexes are strung together in sequence. As long as the first stimulus appears, the conditioned reflex will appear once, which is the dynamic stereotype.
For example, getting up in the morning, brushing your teeth, washing your face, eating, dressing for work and a series of activities all start with the alarm clock.