1. Describe why humans have a blind spot:
a. Humans have a blind spot because the spot that the axons meet to form the optic nerve does not have any sensor cells.
2. Describe the functional and anatomical differences between rods and cones: a. Rods: Respond to faint light and are more abundant in the periphery of the eye. Cylindrical shape, similar to a welding rod. b. Cones: Responsible for color vision, provide roughly 90% of input to the brain, and has to do with heightened visual responses. Looks like a cone.
3. Describe the trichromatic and opponent-process theories of color vision: a. Trichromatic Theory: Perception of color occurs through three kinds of cones; short wavelength (blue), medium-wavelength (green), and long-wavelength (red). Each cone responds to colors, but some respond stronger to certain colors. For instance, the long-wavelength cones respond best to reds. Intense light increases the brightness of the color, but it does not change the color itself. b. Opponent-Process Theory: Color is perceived in paired opposites. There are two mechanisms in the brain; one perceives color on a continuum from red to green, and the other from yellow to blue. This theory suggests that bipolar cells are excited by one set of wavelengths, and could be inhibited by another.
4. Trace the process of interpreting auditory information from the stimulus to the interpretation. a. Auditory information is received through our ears which has three parts; outer ear, middle ear, and inner ear. Each part is responsible for picking up different signals. The outer ear helps us locate the source of a sound. The middle ear transforms waves into stronger waves to be interpreted. The inner ear transmits these waves through viscous fluid in the inner ear, and a signal is sent to the brain representing what was heard.
5. Name and describe the major structures of the middle ear. a. The middle ear is composed of the eardrum and the ossicles (tiny bones). There are three of these tiny bones; the malleus, incus, and the stapes. These ossicles vibrate upon the receiving of sound waves. The ossicles amplify the signal and send it to the inner ear to process the signal and send it to the brain.
6. Describe the factors that contribute to sound localization. a. There are three cues that support sound localization; sound shadow, time of arrival, and phase difference. Sound shadow refers to the space past your ears after the sound reaches your ears. The difference in time for sound to reach both ears, where the difference is minimal, makes locating the sound easier. Phase difference between the ears helps provide the location of sound with frequencies up to 1500 Hz.
7. What is the function of the somatosensory system? a. The somatosensory system is the feeling of your body and its movements. This includes touch, different temperatures, pain, itching feeling, tickling, and how our joints move. Anything we physically feel is because of the somatosensory system.
8. Name and describe the parts of the brain involved in the chemical sense of taste. a. With taste, the brain reacts from various areas. The somatosensory cortex reacts when food touches our tongue. The insula, located just below the corpus callosum, is the primary taste cortex. This cortex has hemispheres that respond Ipsilateral to the sides of the tongue as well.
9. Describe the areas and major functions of the primary motor cortex. a. The primary motor cortex is located in the precentral gyrus, which is in the frontal lobe. Impulses that control muscles are controlled by axons in the precentral gyrus that are connected to the brainstem and spinal cord. It is responsible for most of our movement, when we think about movement the primary motor cortex activates and forces an outcome. Depending on the side of the body, the opposite side of the primary motor cortex may be responsible for that movement.
10. Describe Parkinson’s disease and Huntington’s disease. a. Parkinson’s disease – Causes involuntary, rigid, muscle tremors, slow movement, and physical and mental activity has increased difficulty. This disease is caused when the specialized cells in the basal ganglia, which are responsible for learning to stop or start movement, begin to die off. b. Huntington’s disease – a severe neurological disorder that affects only 1 in 10,000 people in the United States. People who suffer from this disease exhibit random arm jerks and facial expressions. As the disease progresses these jerks turn into tremors and spread throughout the body. This drastically affects daily functions such as walking, talking, or any other voluntary functions that we take for granted. Huntington’s disease is caused by a dominant gene on chromosome #4, which is very rare because any mutant gene is classified as recessive (Kalat, 2013).
Kalat, J. W. (2013). Biological Psychology (11th ed.). Cengage Learning.