Resumão: SISTEMA NERVOSO

Summary

In this lesson, Professor Natália Henneck provides an overview of the human nervous system, breaking it down into the central nervous system (CNS) and peripheral nervous system (PNS). The CNS consists of the brain and spinal cord, responsible for complex functions like memory, reasoning, and voluntary motor control. The PNS includes sensory and motor nerves, classified as afferent, efferent, or mixed. The autonomic nervous system (ANS), controlling involuntary functions, is subdivided into the sympathetic (fight or flight) and parasympathetic (rest and digest) systems. The lesson also highlights the protective structures like meninges and cerebrospinal fluid, essential for maintaining CNS health.

Takeaways

• 😀 The nervous system is divided into the central nervous system (CNS) and peripheral nervous system (PNS).
• 😀 The CNS consists of the brain (encéfalo) and spinal cord (medula espinal), which are responsible for complex tasks like memory, reasoning, and voluntary motor control.
• 😀 The CNS is protected by meninges (pia mater, arachnoid mater, dura mater), the skull, and vertebrae, as well as cerebrospinal fluid (CSF) that helps nourish and remove waste.
• 😀 The spinal cord passes through the vertebral canal and branches into spinal nerves, which are part of the PNS.
• 😀 The spinal cord has a 'H'-shaped structure with grey matter (substance cinzenta) forming the center, split into posterior and anterior horns.
• 😀 The PNS consists of nerves (spinal and cranial), which carry sensory (afferent) and motor (efferent) signals to and from the CNS.
• 😀 Afferent nerves carry sensory information from the body to the CNS, while efferent nerves transmit motor signals from the CNS to muscles and glands.
• 😀 Some nerves are mixed, containing both sensory and motor neurons, allowing them to carry both types of information.
• 😀 The PNS is further divided into the somatic nervous system, which controls voluntary movements (e.g., skeletal muscles), and the autonomic nervous system (ANS), which controls involuntary functions (e.g., organs and glands).
• 😀 The autonomic nervous system is split into the sympathetic system, which activates the 'fight or flight' response, and the parasympathetic system, which calms the body and regulates functions like digestion during restful states.

Q & A

What are the main components of the Central Nervous System (CNS)?

The Central Nervous System (CNS) is composed of the brain (encéfalo) and the spinal cord (medula espinal).

What is the function of the meninges in the CNS?

The meninges are protective layers that cover the CNS. They consist of three layers: the pia mater (innermost), the arachnoid mater (middle), and the dura mater (outermost).

What role does cerebrospinal fluid (liquido cefalorraquidiano) play in the CNS?

Cerebrospinal fluid circulates around the CNS, providing protection, nourishment, and removing waste from the system.

What is the function of the Peripheral Nervous System (PNS)?

The PNS is responsible for conducting sensory and motor stimuli to and from the CNS. It includes spinal and cranial nerves.

How are spinal nerves formed in the PNS?

Spinal nerves are formed by the branching of the spinal cord through the vertebral foramina, leading to the formation of nerve roots that extend to the peripheral areas of the body.

What is the difference between sensory (afferent) and motor (efferent) nerves?

Sensory nerves (afferent) carry stimuli from the body's receptors to the CNS, while motor nerves (efferent) carry stimuli from the CNS to muscles and glands in the body.

What are mixed nerves, and how do they function?

Mixed nerves contain both sensory (afferent) and motor (efferent) neurons, allowing them to carry both types of information to and from the CNS.

What is the difference between the somatic and autonomic nervous systems?

The somatic nervous system controls voluntary movements, such as skeletal muscle movement, while the autonomic nervous system controls involuntary functions, such as the regulation of internal organs.

What are the main roles of the sympathetic and parasympathetic divisions of the autonomic nervous system?

The sympathetic nervous system activates the body's 'fight or flight' response, increasing heart rate, dilating pupils, and preparing the body for stress. The parasympathetic nervous system promotes relaxation, reducing heart rate and aiding digestion during restful states.

What is the structure of the spinal cord, and how is it organized?

The spinal cord has an H-shaped cross-section, with gray matter (substance cinzenta) in the center. It is divided into anterior and posterior horns, with sensory nerves entering the posterior horns and motor nerves exiting through the anterior horns.