Unit 2: Biological Bases Of Behavior

A neuron is the basic building block of the nervous system. It is a specialized cell that transmits information through electrical and chemical signals. Neurons are responsible for receiving, processing, and transmitting information throughout the body. They have a unique structure, including a cell body called the soma, which contains the nucleus and other essential organelles. Neurons also have dendrites to receive signals, an axon to transmit signals, and terminal branches to connect with other neurons or muscles. Therefore, a neuron is the correct answer as it is the fundamental unit of the nervous system.

The heartbeat is accomplished by the autonomic branch of the nervous system. The autonomic nervous system controls involuntary functions in the body, including the regulation of the heart rate. It consists of two divisions: the sympathetic division, which increases heart rate and prepares the body for action, and the parasympathetic division, which decreases heart rate and promotes relaxation. Therefore, the autonomic branch of the nervous system is responsible for the coordination and regulation of the heartbeat.

An EEG (electroencephalogram) is a recording of brain waves using electrodes placed on the scalp. It is a non-invasive procedure that measures and records the electrical activity of the brain. This technique is commonly used in clinical and research settings to study brain function, diagnose neurological disorders, and monitor brain activity during sleep or in response to stimuli.

In a split-brain procedure, the corpus callosum is severed. The corpus callosum is a thick band of nerve fibers that connects the left and right hemispheres of the brain. By severing this connection, the communication between the two hemispheres is disrupted, resulting in a split-brain condition. This procedure is sometimes performed as a treatment for severe epilepsy to prevent the spread of seizures from one hemisphere to the other.

Phineas Gage's case demonstrated that damage to the frontal lobe of the brain can result in significant personality changes. This suggests that the frontal lobe plays a crucial role in regulating personality traits and social behavior. Gage survived a severe brain injury when an iron rod penetrated his frontal lobe, leading to alterations in his behavior, decision-making, and emotional control. This evidence supports the assertion that trauma to the frontal lobe can result in personality changes while still allowing the individual to survive.

Endorphins are natural, opiate-like neurotransmitters that are linked to pain control. They are produced by the body in response to various stimuli, such as exercise, laughter, and stress. Endorphins bind to opioid receptors in the brain and spinal cord, reducing the perception of pain and producing feelings of pleasure and well-being. They are often referred to as the body's natural painkillers and are responsible for the "runner's high" experienced during intense exercise.

Plasticity refers to the brain's ability to reorganize and adapt after damage or injury. In this case, Peter's left frontal lobe damage resulted in the loss of his ability to speak. However, his brain was able to compensate for this loss by reorganizing and taking over the lost function, allowing him to recover some of his speech abilities. This ability of the brain to adapt and rewire itself is known as plasticity.

Neurotransmitters are biochemical substances that are released into the synaptic cleft to stimulate or suppress other neurons. They are responsible for transmitting signals between neurons, allowing for communication within the nervous system. Receptors, hormones, interneurons, and neurohormones are not directly involved in this process.

The hypothalamus is the part of the limbic system that maintains homeostasis in the body in terms of temperature, hunger, and thirst. It is responsible for regulating various bodily functions such as body temperature, appetite, thirst, and sleep. It also plays a crucial role in controlling the release of hormones from the pituitary gland, which further regulates various physiological processes in the body.

Neural signals travel along a neuron in the following order: dendrite, soma, axon, terminal branches. This is because dendrites receive incoming signals from other neurons, which are then passed to the soma (cell body). From the soma, the signals are then transmitted through the axon, which is a long fiber that carries the signals away from the soma. Finally, the signals reach the terminal branches, which release neurotransmitters to communicate with the next neuron in the circuit.

The pons is responsible for regulating sleep and dreaming. It is a part of the brainstem that plays a crucial role in controlling various physiological functions, including sleep-wake cycles. The pons contains nuclei that produce neurotransmitters involved in promoting sleep and inhibiting wakefulness. Additionally, it helps coordinate the rapid eye movement (REM) sleep, which is the stage of sleep associated with vivid dreaming. Therefore, the pons is closely involved in the regulation of sleep and dreaming processes.

The nervous system and the endocrine system form the body's two communication systems. The nervous system consists of the brain, spinal cord, and nerves, and it uses electrical signals to transmit information. The endocrine system consists of glands that secrete hormones into the bloodstream, and it uses chemical signals to communicate. Together, these two systems work in harmony to regulate and coordinate the body's functions and responses to internal and external stimuli.

The split-brain patient saw the word "ON" in their left visual field, which is processed by the right hemisphere of the brain. However, when asked to indicate what they saw, the patient points to "HER," which suggests that the left hemisphere, responsible for language and speech, is not aware of the information processed by the right hemisphere. This phenomenon is known as the "left hemisphere interpreter" and occurs because the left hemisphere tries to make sense of the information it receives, even if it is not directly aware of it.

A neurotransmitter is a signal molecule that transmits nerve impulses across synapses. When a nerve impulse reaches the end of a neuron, it triggers the release of neurotransmitters into the synapse. These neurotransmitters then bind to receptors on the receiving neuron, allowing the impulse to be transmitted from one neuron to another. Therefore, the correct answer is neurotransmitter.

Serotonin is a neurotransmitter that plays a crucial role in regulating various functions, including mood, sleep patterns, and appetite. Imbalances in serotonin levels have been linked to mood disorders such as depression and anxiety. It also influences sleep-wake cycles, and its effects on appetite contribute to feelings of satiety and satisfaction after eating.