Sympathetic Nervous System Quiz Questions

A neuron is the functional unit of the nervous system. It is a specialized cell that transmits information through electrical and chemical signals. Neurons have a cell body, which contains the nucleus and other organelles, and an axon, which is a long, slender projection that carries the electrical signals away from the cell body. Synapses are the connections between neurons where the signals are transmitted. Therefore, the correct answer is neuron.

Stimulation by the sympathetic nervous system leads to increased heart rate. The sympathetic nervous system is responsible for the "fight or flight" response in the body, which prepares the body for action. When activated, it increases heart rate to pump more blood to the muscles and organs, providing them with oxygen and nutrients needed for increased activity. This response is essential in situations where the body needs to respond quickly to a threat or stressor.

The resting potential of a cell refers to the electrical charge difference across the cell membrane when the cell is at rest. This potential exists due to the concentration gradients of ions, particularly sodium and potassium. The correct answer states that the concentration of sodium is much higher outside the cell than inside. This is true because sodium ions are actively pumped out of the cell by the sodium-potassium pump, creating a higher concentration of sodium outside the cell. This concentration gradient contributes to the resting potential of the cell.

When the threshold potential is reached, it means that the membrane potential has reached a critical level that triggers the opening of voltage-gated sodium channels. This allows sodium ions to rapidly enter the cell, causing depolarization and the generation of an action potential. At the same time, potassium channels start to open, allowing potassium ions to exit the cell, which helps in repolarization. As a result, the interior of the cell becomes more negative compared to the outside. Therefore, once the threshold potential is reached, an action potential becomes inevitable due to the sequential events of channel opening and closing.

The motor nervous system is responsible for carrying signals from the brain and spinal cord to the skeletal muscles, allowing for voluntary movements. The autonomic nervous system, on the other hand, controls involuntary actions such as digestion and heart rate. The sympathetic and parasympathetic nervous systems are both part of the autonomic nervous system and regulate different bodily functions. Therefore, the motor nervous system is the correct division of the human nervous system that carries signals to skeletal muscles.

The action potential changes in frequency as the strength of the stimulus changes. This means that the number of action potentials generated per unit of time varies with the strength of the stimulus. A stronger stimulus will result in a higher frequency of action potentials, while a weaker stimulus will result in a lower frequency. The duration, amplitude, and strength of the action potential may remain relatively constant, but it is the frequency that is directly influenced by the strength of the stimulus.

Flatworms are the simplest animals to display cephalization and centralization of the nervous system. Cephalization refers to the concentration of sensory organs and nervous tissue at the anterior end of the animal. Flatworms have a distinct head region with a concentration of nerve cells and sensory structures, such as eyespots. Centralization of the nervous system means that the nerve cells are organized into a centralized mass, which is seen in flatworms with their ladder-like nervous system. Sponges, echinoderms, and cnidarians do not exhibit the same level of cephalization and centralization as flatworms.

Serotonin is a neurotransmitter that is associated with various functions in the body, including sleep, mood, attention, and learning. It plays a crucial role in regulating these processes and maintaining overall well-being. Serotonin is involved in the sleep-wake cycle, influencing both the quality and duration of sleep. It also affects mood and emotions, with low levels of serotonin being linked to depression and anxiety. Additionally, serotonin is involved in attention and learning, as it helps in transmitting signals between nerve cells in the brain. Overall, serotonin is a vital neurotransmitter for several important physiological and psychological functions.

The correct answer is synaptic cleft. The synaptic cleft is the small gap between the transmitting neuron (presynaptic neuron) and the receiving neuron (postsynaptic neuron) in a chemical synapse. It is the space where neurotransmitters are released by the presynaptic neuron and received by the postsynaptic neuron, allowing for communication between the two neurons.

Stimulation by the parasympathetic nervous system causes pupil constriction. This is because the parasympathetic system is responsible for controlling the body's "rest and digest" response, which includes activities such as constricting the pupils to reduce the amount of light entering the eyes.