Question

Our ability to make our legs move as we walk across the room is controlled by the ________ nervous system. a. autonomic b. somatic c. sympathetic d. parasympathetic

Short answer

The nervous system responsible for our ability to make our legs move as we walk across the room is the somatic nervous system. Therefore, the correct answer is option b.

Step-by-step solution

Understanding the Human Nervous System

Firstly, it is necessary to understand the structures and functions of the four parts of the nervous system mentioned in the options. The autonomic nervous system controls involuntary and automatic bodily functions like heart rate. The somatic nervous system is responsible for the movement of voluntary muscles, including those related to locomotion. The sympathetic nervous system is part of the autonomic system and controls the body's response during perceived threat. The parasympathetic nervous system is also part of the autonomic system and controls rest and digest functions.

Map the Given Functions to the Relevant Parts

Now map the function mentioned in the question (making the legs move as we walk across the room) to the part of the nervous system responsible for it, based on the functions of each part of the nervous system studied in step 1. As per this analysis, the nerve system responsible for voluntary leg movements during walking will be the somatic nervous system.

Key concepts

Autonomic Nervous System

The autonomic nervous system (ANS) is an intricate network of neurons that governs involuntary bodily functions. It operates without conscious control, managing vital operations such as heartbeat, respiration, digestion, and metabolic processes.

Divided into two branches – the sympathetic and parasympathetic nervous systems – the ANS ensures our internal environment remains stable and responds appropriately to stress and relaxation. While both branches work continuously, they have opposing effects on the body. For instance, the sympathetic nervous system readies the body for 'fight or flight' situations, whereas the parasympathetic system promotes 'rest and digest' activities.

Understanding the ANS is essential for grasping how our bodies maintain homeostasis amidst various internal and external challenges.

Somatic Nervous System

The somatic nervous system is the part of our nervous system responsible for the voluntary movement of our muscles. It encompasses the nerves that transmit sensory information from the outer parts of the body to the central nervous system and the motor nerve fibers that connect to skeletal muscles. Essentially, when you decide to walk across a room, it's the somatic nervous system that relays this conscious decision, ensuing in muscle contractions that enable you to move.

It is key to note that the somatic nervous system is under our voluntary control. For example, when your brain sends a signal to move your arm, motor neurons from the somatic system will ensure your arm muscles contract accordingly. This system is crucial in activities ranging from simple actions like gripping a pen to more complex coordination during sports.

Sympathetic Nervous System

Part of the autonomic nervous system, the sympathetic nervous system prepares the body for intense physical activity and is often referred to as the 'fight or flight' system. It is activated under conditions of stress and works to provide the body with a burst of energy needed to respond to threats.

Activation of the sympathetic nervous system results in accelerated heartbeat, increased breathing rate, dilation of the pupils, and release of adrenaline from the adrenal glands, among other physiological changes. These actions collectively prep your muscles with more oxygen and glucose – the fuel they need for a swift and powerful response. Due to its vital role in survival, understanding how the sympathetic nervous system operates can provide insight into how our bodies deal with stress and emergency situations.

Parasympathetic Nervous System

The parasympathetic nervous system is often characterized as the 'rest and digest' system. It serves as a counterpart to the sympathetic system and helps the body to conserve and restore energy. After a stressful situation comes to an end, the parasympathetic nervous system acts to decrease heart rate, enhance digestion, and conserve energy by slowing down the overall pace of the body’s functions.

Involved in routine, restorative processes, the parasympathetic system ensures optimal functioning of the body during relaxed states, including promoting digestion and waste elimination and managing energy storage. A balance between the sympathetic and parasympathetic nervous systems is necessary for a healthy stress response and recovery, and disruptions to this balance can lead to a variety of health issues.