Nervous System Overview

Summary

This transcript provides an engaging introduction to the nervous system, explaining key components like the central nervous system (CNS) and peripheral nervous system (PNS). The CNS, consisting of the brain and spinal cord, communicates with the PNS, which includes sensory and motor nerves. The lecture delves into sensory functions such as touch, pain, temperature, and special senses like sight and hearing. It also discusses motor output, with voluntary control over skeletal muscles and involuntary control over organs, highlighting autonomic nervous system functions like the sympathetic and parasympathetic systems responsible for fight or flight and rest and digest responses.

Takeaways

• 😀 Understanding the nervous system is crucial for answering test questions and applying knowledge in practical scenarios.
• 😀 The Central Nervous System (CNS) consists of the brain and spinal cord, and is responsible for processing and sending out information.
• 😀 The Peripheral Nervous System (PNS) includes 12 pairs of cranial nerves and 31 pairs of spinal nerves, connecting the CNS to the rest of the body.
• 😀 Sensory (afferent) nerves carry information toward the CNS, including touch, pain, temperature, and special senses like sight and hearing.
• 😀 Motor (efferent) nerves carry information away from the CNS to muscles and organs, controlling voluntary and involuntary actions.
• 😀 Voluntary motor control is governed by somatic motor neurons, which control skeletal muscles, while involuntary control is regulated by autonomic neurons.
• 😀 The autonomic nervous system has two branches: sympathetic (fight or flight) and parasympathetic (rest and digest), each with distinct functions.
• 😀 The sympathetic nervous system prepares the body for stress responses, originating from the thoracic and lumbar regions of the spinal cord.
• 😀 The parasympathetic nervous system promotes calming and restorative functions, originating from the brain and sacral regions of the spinal cord.
• 😀 The nervous system operates through complex pathways of afferent and efferent nerves, each with specific roles in sensory input and motor output.

Q & A

What is the central nervous system (CNS) composed of?

The central nervous system (CNS) is composed of the brain and the spinal cord.

What does the peripheral nervous system (PNS) consist of?

The peripheral nervous system (PNS) consists of all the nerves that come off the brain (cranial nerves) and the spinal cord (spinal nerves). These nerves go to various parts of the body, such as the arms, legs, internal organs, and pelvic organs.

What is the difference between sensory and motor nerves?

Sensory nerves (afferent) carry information toward the central nervous system, such as touch, pain, temperature, and special senses (sight, smell, taste, hearing). Motor nerves (efferent) carry information away from the central nervous system, controlling muscles and organs.

What types of sensory information are processed by the nervous system?

Sensory information processed by the nervous system includes touch, temperature, pain (nociception), stretch (from muscles or organs), and the five special senses: sight, smell, taste, hearing, and balance.

What are somatic motor neurons responsible for?

Somatic motor neurons are responsible for voluntary control of skeletal muscles. They stimulate muscles to contract, such as when you move your limbs or other skeletal muscles.

What is the autonomic nervous system and what does it control?

The autonomic nervous system controls involuntary functions such as heart rate, digestion, and breathing. It operates automatically and regulates smooth muscle, cardiac muscle, and glands.

What are the two divisions of the autonomic nervous system?

The autonomic nervous system has two divisions: the sympathetic division (associated with the 'fight or flight' response) and the parasympathetic division (associated with the 'rest and digest' response).

Where do the sympathetic nerves originate from in the spinal cord?

The sympathetic nerves originate from the thoracic and lumbar regions of the spinal cord, which is why it is sometimes referred to as the thoracolumbar division.

What is the parasympathetic nervous system responsible for, and where do its nerves originate?

The parasympathetic nervous system is responsible for the 'rest and digest' functions, such as slowing the heart rate and stimulating digestion. Its nerves originate from the brain and sacral region of the spinal cord (craniosacral division).

What is the significance of the cerebellum in the central nervous system?

The cerebellum, located at the back of the brain, plays a crucial role in motor control, coordination, balance, and fine-tuning of voluntary movements. It was initially omitted in the drawing but is part of the central nervous system.