UNIT - Neuroscience and Behavior Learning Objectives
1. Explain why psychologists are concerned with human biology.
Psychologists are concerned with the biology of the brain because by learning about how the brain functions and how certain chemicals cause certain effects, they can learn about the behavior that results from it, which is ultimately what psychologists are trying to achieve. A human’s thought process is largely influenced by chemicals that control things like moods, impulses, even mental illness which is caused by an imbalance in the chemicals.
2. Describe the structure of a neuron, and explain how neural impulses are generated.
The neuron, a cell in the nervous system for information transfer, has various components in its structure. The dendrites are regions of information input and can end with sensory endings that respond to stimuli such as light or pressure. The soma is the cell body of the neuron and contains the nucleus and the cytoplasmic organelles of an average cell. If the soma is destroyed, the neuron dies, as it is the living part of the cell. The axon cone is the region that is most sensitive to changes in the electrical charge on the neuron membrane. It exhibits the presence of a nerve impulse called the action potential. The axon is an electrically excitable cytoplasmic filament that conducts the action potentials. At the axon terminal, axonal arborization is a branching of the axon for communicating with other neurons through synaptic contacts. A nerve impulse begins when a stimulus disturbs the plasma membrane on a dendrite, causing sodium channels to open. This affects neighboring voltage gated channels, which open, moving depolarization along the membrane. This is called an action potential. The sodium potassium pumps in the neuron then work to repolarize the areas along the membrane.
3. Describe how nerve cells communicate, and discuss the impact of neurotransmitters and drugs on human behavior.
Nerve cells communicate using neurotransmitters. They generate action potentials that travel down the membrane. The neurotransmitters fit onto the receptors on the neighboring neuron, passing on their message. The effect of neurotransmitters and drugs on human behavior can vary greatly. For example, endorphins act as opiates and have effects such as a “runner’s high” or tolerance to pain in life-threatening situations. Or epinephrine, or adrenaline, is responsible for a human’s “fight or flight” instinct. It increases heart activity, therefore increasing blood flow to the brain. Drugs have varied effects too. Some, like heroin, mimic certain neurotransmitters and attach to your receptors, but have an effect different to that of the actual neurotransmitter. This results in altered behavior. Some result in the brain stopping producing certain natural neurotransmitters, which also alters behavior as the brain is not getting the usual messages.
The Nervous System
4. Identify the major divisions of the nervous system and describe their functions, noting the three types of neurons that transmit information through the system.
The major divisions of the nervous system are the central nervous system and the peripheral nervous system. The central nervous system consists of the brain and spinal cord and coordinates the activity of all parts of the body. It also controls behavior. This contains the majority of the nervous system and the brain and spinal cord are protected by the skull and vertebrae, respectively. The peripheral nervous system is made up of the nerves and ganglia outside of the brain and spinal cord. This area is unprotected and subject to toxins. The peripheral nervous system is divided into two sections. The first is the autonomic nervous system, which controls visceral functions such as heart rate, digestion, respiratory rate, salivation, perspiration, pupillary dilation, urination, and sexual arousal. The second is the somatic