PSYCH 111: Introduction to Psychology: Week 7: Chapter 3 Quizzes: Biopsychology

The Correct Answer is:

b. myelin sheath

Multiple sclerosis (MS) is a chronic autoimmune disorder in which the immune system attacks the myelin sheath, the protective covering surrounding the axons of neurons. The breakdown of myelin disrupts the efficient transmission of electrical impulses between neurons, leading to slowed or blocked communication within the nervous system. This results in symptoms such as muscle weakness, fatigue, balance problems, vision disturbances, and difficulty with coordination and motor control.

Why the other options are incorrect:

a. soma

This is incorrect because the soma, or cell body, processes information but is not directly affected in multiple sclerosis. While communication problems eventually impact the soma’s ability to integrate signals, the disease primarily targets the myelin covering the axons.

c. synaptic vesicles

This is incorrect because synaptic vesicles store and release neurotransmitters into the synaptic cleft. Multiple sclerosis does not damage vesicles directly but disrupts electrical signaling before neurotransmitter release occurs.

d. dendrites

This is incorrect because dendrites are responsible for receiving incoming signals from other neurons. In MS, dendrites are not the main site of damage. The disease specifically attacks the myelin along the axons, impairing signal transmission rather than blocking dendritic input.

The Correct Answer is:

B. PET scans track blood flow using a radioactive tracer but provide limited detail and timing accuracy

PET scans work by injecting or consuming a mildly radioactive tracer that travels through the bloodstream. As certain brain areas become active, they require more oxygen and glucose, leading to increased blood flow. The tracer highlights these changes, allowing researchers to create a visual map of active and less active brain regions. However, PET scans have limitations, including low image resolution, poor timing precision, and exposure to small amounts of radiation. Today, fMRI is preferred for safer and more detailed imaging.

Why the other options are incorrect:

A. PET scans create detailed images of brain structures without using radiation

This is incorrect because PET scans do use radiation through a radioactive tracer, and they are not ideal for showing fine structural details. Techniques like MRI or CT scans are better suited for high-resolution images of brain anatomy.

C. PET scans measure electrical activity in the brain and detect individual neuron firing

This is incorrect because PET scans do not measure electrical activity; they measure metabolic activity and blood flow. To detect electrical signals and neuron firing, tools like EEG (electroencephalography) are used instead.

D. PET scans have replaced fMRI because they produce the clearest and safest brain images

This is incorrect because PET scans have not replaced fMRI; in fact, the opposite is true. Functional MRI provides better spatial resolution, does not require radiation, and captures more precise brain activity data, making it the preferred method over PET.

The Correct Answer is:

c. parasympathetic nervous system

The parasympathetic nervous system, a branch of the autonomic nervous system, is responsible for promoting relaxation, restoring balance, and maintaining normal body functions after stressful events. It slows the heart rate, lowers blood pressure, aids digestion, and conserves energy, creating a state of calm and rest. This “rest-and-digest” response helps the body recover from heightened arousal and maintain internal stability.

Why the other options are incorrect:

a. somatic nervous system

This is incorrect because the somatic nervous system controls voluntary movements of skeletal muscles, such as walking or picking up objects. It does not regulate states of relaxation or rest.

b. sympathetic nervous system

This is incorrect because the sympathetic nervous system triggers the “fight-or-flight” response, increasing heart rate, blood pressure, and alertness during stressful situations. Its activation leads to heightened arousal, not a state of ease.

d. spinal cord

This is incorrect because the spinal cord acts as a communication pathway between the brain and the body, transmitting sensory and motor signals. While essential for neural processing, it does not directly regulate feelings of relaxation or calmness.

The Correct Answer is:

B. It examines how gene-environment interactions can cause the same genotype to produce different phenotypes

Epigenetics is the study of how environmental factors influence gene expression without changing the DNA sequence itself. It explains how individuals with the same genotype can display different phenotypes based on experiences, lifestyle, diet, stress, and other environmental exposures. Epigenetic changes occur through mechanisms like DNA methylation and histone modification, which switch genes “on” or “off.” This field highlights the dynamic relationship between biology and environment in shaping traits, behaviors, and susceptibility to psychological and physical disorders.

Why the other options are incorrect:

A. It studies how genes alone determine fixed traits without environmental influence

This is incorrect because epigenetics specifically focuses on how environmental factors interact with genes. Traits are not determined by DNA alone; environmental triggers can alter how genes are expressed without changing the genetic code itself.

C. It focuses only on inherited mutations that permanently alter the DNA sequence

This is incorrect because mutations change the DNA structure itself, while epigenetics involves reversible changes in gene expression. Epigenetic mechanisms affect whether genes are activated or silenced but do not permanently rewrite the DNA sequence.

D. It explains how hormones regulate reproduction and sexual development exclusively

This is incorrect because hormonal regulation is a function of the endocrine system, not epigenetics. While hormones can influence gene activity, epigenetics studies the broader effects of environmental and lifestyle factors on how genes are expressed across multiple biological systems.

The Correct Answer is:

B. Genes influence not only physical characteristics but also behavioral traits, including personality, sexual orientation, and spirituality

Research shows that genes play a significant role in shaping behavioral characteristics as well as physical traits. Genetic studies have identified linkages between specific genes and factors such as personality traits, sexual orientation, cognitive abilities, and even levels of spirituality. While genes create a biological foundation for these traits, environmental factors interact with genetic predispositions to influence how they are expressed, leading to diversity in behaviors and personal characteristics among individuals.

Why the other options are incorrect:

A. Genes only determine physical traits and have no effect on personality or behavior

This is incorrect because studies consistently show that genetics contribute to behavioral tendencies and psychological characteristics, not just physical attributes.

C. Behavior is entirely shaped by the environment, and genes play no role in influencing it

This is incorrect because while the environment strongly affects behavior, it works alongside genetic influences. Ignoring genetics overlooks a major contributor to personality and behavioral differences.

D. Behavioral characteristics are random and unrelated to both genes and the environment

This is incorrect because behaviors are not random; they are shaped by interactions between genes and environmental factors, meaning neither acts independently of the other.

The Correct Answer is:

d. glucagon and insulin

The pancreas plays a vital role in regulating blood sugar levels by secreting two key hormones: insulin and glucagon. Insulin lowers blood glucose by promoting its uptake into cells for energy or storage, while glucagon raises blood glucose by stimulating the liver to release stored glucose. Together, they maintain homeostasis of blood sugar levels, ensuring the body has a stable energy supply necessary for proper functioning.

Why the other options are incorrect:

a. estrogen and progesterone

This is incorrect because these hormones are secreted by the ovaries in females, not the pancreas. They regulate female reproductive functions, including the menstrual cycle and pregnancy.

b. norepinephrine and epinephrine

This is incorrect because these hormones are secreted by the adrenal glands, not the pancreas. They prepare the body for fight-or-flight responses during stress by increasing heart rate, blood pressure, and energy release.

c. thyroxine and oxytocin

This is incorrect because thyroxine is secreted by the thyroid gland to regulate metabolism, while oxytocin is produced by the hypothalamus and released by the pituitary gland to influence childbirth, bonding, and social behaviors.

The Correct Answer is:

B. A sudden, permanent change in a gene that can alter its function and potentially affect traits

A mutation is a sudden, permanent change in the DNA sequence of a gene. Mutations can occur naturally or be caused by external factors such as radiation, chemicals, or viral infections. Depending on where they occur, mutations can be beneficial, harmful, or neutral. Some mutations lead to variations in traits that may improve survival, while others may cause genetic disorders or diseases. Mutations contribute to genetic diversity, which plays an important role in evolution.

Why the other options are incorrect:

A. A temporary change in DNA that disappears after a few cell divisions

This is incorrect because mutations are permanent changes in the DNA sequence; they do not simply disappear over time.

C. A random shift in chromosomes that always produces harmful effects

This is incorrect because not all mutations are harmful. Some have no effect (neutral mutations), while others may benefit survival by creating advantageous traits.

D. A controlled change in DNA caused by the body to improve survival

This is incorrect because mutations occur spontaneously or due to environmental factors, not as a deliberate biological process. Evolution acts on existing mutations through natural selection, but the mutations themselves are not planned.

The Correct Answer is:

C. It manages conscious and voluntary activities such as muscle movements

The somatic nervous system is a subdivision of the peripheral nervous system responsible for controlling voluntary movements and conscious activities. It carries motor signals from the central nervous system to skeletal muscles, allowing actions like walking, writing, and speaking. It also transmits sensory information from the body to the CNS, enabling perception and coordination. This system allows us to intentionally interact with and respond to our environment through controlled movements.

Why the other options are incorrect:

A. It controls involuntary processes like heartbeat and digestion

This is incorrect because involuntary processes are regulated by the autonomic nervous system, not the somatic nervous system. The autonomic system manages functions such as breathing, heart rate, and digestion, which occur automatically without conscious control.

B. It regulates emotional responses and hormonal release

This is incorrect because emotional regulation and hormonal release are primarily controlled by the limbic system and endocrine system. While the somatic system affects voluntary actions, emotional and hormonal functions involve other brain regions and chemical messengers, not direct somatic control.

D. It sends signals only between the spinal cord and internal organs

This is incorrect because the somatic nervous system primarily connects the CNS to skeletal muscles, not internal organs. Communication with internal organs is a function of the autonomic nervous system, which regulates activities like breathing, digestion, and heart function involuntarily.

The Correct Answer is:

B. It regulates homeostasis, controls appetite, body temperature, and connects the nervous and endocrine systems

The hypothalamus is a small but crucial structure located at the base of the brain that plays a central role in maintaining homeostasis — the body’s internal balance. It regulates vital processes like body temperature, hunger, thirst, and blood pressure. Additionally, it acts as a bridge between the nervous and endocrine systems by controlling the pituitary gland, influencing hormone release. It also plays a significant role in regulating sexual motivation, emotional responses, and behavior.

Why the other options are incorrect:

A. It processes visual information and interprets color and motion

This is incorrect because visual processing occurs in the occipital lobe, not the hypothalamus. The hypothalamus focuses on maintaining the body’s internal balance, whereas the occipital lobe interprets images and motion from visual input.

C. It manages voluntary muscle coordination and problem-solving skills

This is incorrect because muscle coordination is primarily controlled by the cerebellum, while decision-making and problem-solving are functions of the frontal lobe. The hypothalamus instead regulates automatic, involuntary functions related to survival and hormonal balance.

D. It stores long-term memories and processes auditory information exclusively

This is incorrect because long-term memory storage is handled by the hippocampus, and auditory processing occurs in the temporal lobe. The hypothalamus is responsible for regulating physiological states and connecting the nervous system with the endocrine system, not managing memory or hearing.