# 3.E: Biopsychology (Exercises)

## 3.1: Human Genetics

Psychological researchers study genetics in order to better understand the biological basis that contributes to certain behaviors. While all humans share certain biological mechanisms, we are each unique. And while our bodies have many of the same parts—brains and hormones and cells with genetic codes—these are expressed in a wide variety of behaviors, thoughts, and reactions.

### Review Questions

#### Q1

A(n) ________ is a sudden, permanent change in a sequence of DNA.

1. allele
2. chromosome
3. epigenetic
4. mutation

#### Q2

________ refers to a person’s genetic makeup, while ________ refers to a person’s physical characteristics.

1. Phenotype; genotype
2. Genotype; phenotype
3. DNA; gene
4. Gene; DNA

#### Q3

________ is the field of study that focuses on genes and their expression.

1. Social psychology
2. Evolutionary psychology
3. Epigenetics
4. Behavioral neuroscience

#### Q4

Humans have ________ pairs of chromosomes.

1. $$15$$
2. $$23$$
3. $$46$$
4. $$78$$

### Critical Thinking Questions

#### Q5

The theory of evolution by natural selection requires variability of a given trait. Why is variability necessary and where does it come from?

### Personal Application Questions

#### Q6

You share half of your genetic makeup with each of your parents, but you are no doubt very different from both of them. Spend a few minutes jotting down the similarities and differences between you and your parents. How do you think your unique environment and experiences have contributed to some of the differences you see?

### Solution

D

B

C

B

#### S5

Variability is essential for natural selection to work. If all individuals are the same on a given trait, there will be no relative difference in their reproductive success because everyone will be equally adapted to their environments on that trait. Mutations are one source of variability, but sexual reproduction is another important source of variation given that individuals inherit half of their genetic makeup from each of their parents.

## 3.2: Cells of the Nervous System

Learning how the cells and organs (like the brain) function, help us understand the biological basis behind human psychology. The nervous system is composed of two basic cell types: glial cells (also known as glia) and neurons. Glial cells, which outnumber neurons ten to one, are traditionally thought to play a supportive role to neurons, both physically and metabolically.

### Review Questions

#### Q1

The ________ receive(s) incoming signals from other neurons.

1. soma
2. terminal buttons
3. myelin sheath
4. dendrites

#### Q2

A(n) ________ facilitates or mimics the activity of a given neurotransmitter system.

1. axon
2. SSRI
3. agonist
4. antagonist

#### Q3

Multiple sclerosis involves a breakdown of the ________.

1. soma
2. myelin sheath
3. synaptic vesicles
4. dendrites

#### Q4

An action potential involves $$Na^+$$ moving ________ the cell and $$K^+$$ moving ________ the cell.

1. inside; outside
2. outside; inside
3. inside; inside
4. outside; outside

### Critical Thinking Questions

#### Q5

Cocaine has two effects on synaptic transmission: it impairs reuptake of dopamine and it causes more dopamine to be released into the synapse. Would cocaine be classified as an agonist or antagonist? Why?

#### Q6

Drugs such as lidocaine and novocaine act as $$Na^+$$ channel blockers. In other words, they prevent sodium from moving across the neuronal membrane. Why would this particular effect make these drugs such effective local anesthetics?

### Personal Application Question

#### Q7

Have you or someone you know ever been prescribed a psychotropic medication? If so, what side effects were associated with the treatment?

### Solution

D

C

B

A

#### S5

As a reuptake inhibitor, cocaine blocks the normal activity of dopamine at the receptor. The function causing more dopamine to be released into the synapse is agonist because it mimics and strengthens the effect of the neurotransmitter. Cocaine would be considered an agonist because by preventing the enzymatic degradation of the neurotransmitters, it increases the potential time that these neurotransmitters might be active in the synapse.

#### S6

The action potential is initiated by an influx of Na+ into the neuron. If this process is prevented, then no action potentials in neurons in a given area will occur. Therefore, any painful stimuli would not result in action potentials carrying that information to the brain.

## 3.3: Parts of the Nervous System

The nervous system can be divided into two major subdivisions: the central nervous system (CNS) and the peripheral nervous system (PNS), shown in the figure below. The CNS is comprised of the brain and spinal cord; the PNS connects the CNS to the rest of the body. In this section, we focus on the peripheral nervous system; later, we look at the brain and spinal cord.

### Review Questions

#### Q1

Our ability to make our legs move as we walk across the room is controlled by the ________ nervous system.

1. autonomic
2. somatic
3. sympathetic
4. parasympathetic

#### Q2

If your ________ is activated, you will feel relatively at ease.

1. somatic nervous system
2. sympathetic nervous system
3. parasympathetic nervous system
4. spinal cord

#### Q3

The central nervous system is comprised of ________.

1. sympathetic and parasympathetic nervous systems
2. organs and glands
3. somatic and autonomic nervous systems
4. brain and spinal cord

#### Q4

Sympathetic activation is associated with ________.

1. pupil dilation
2. storage of glucose in the liver
3. increased heart rate
4. both A and C

### Critical Thinking Questions

#### Q5

What are the implications of compromised immune function as a result of exposure to chronic stress?

#### Q6

Examine Fig. 3.3.2,  illustrating the effects of sympathetic nervous system activation. How would all of these things play into the fight or flight response?

### Personal Application Questions

#### Q7

Hopefully, you do not face real physical threats from potential predators on a daily basis. However, you probably have your fair share of stress. What situations are your most common sources of stress? What can you do to try to minimize the negative consequences of these particular stressors in your life?

### Solution

B

C

D

D

#### S5

Chronic stress can lead to increased susceptibility to bacterial and viral infections, and potentially an increased risk of cancer. Ultimately, this could be a vicious cycle with stress leading to increased risk of disease, disease states leading to increased stress and so on.

#### S6

Most of these effects directly impact energy availability and redistribution of key resources and heightened sensory capacity. The individual experiencing these effects would be better prepared to fight or flee.

## 3.4: The Brain and Spinal Cord

The brain is a remarkably complex organ comprised of billions of interconnected neurons and glia. It is a bilateral, or two-sided, structure that can be separated into distinct lobes. Each lobe is associated with certain types of functions, but, ultimately, all of the areas of the brain interact with one another to provide the foundation for our thoughts and behaviors. In this section, we discuss the overall organization of the brain and the functions associated with different brain areas.

### Review Questions

#### Q1

The ________ is a sensory relay station where all sensory information, except for smell, goes before being sent to other areas of the brain for further processing.

1. amygdala
2. hippocampus
3. hypothalamus
4. thalamus

#### Q2

Damage to the ________ disrupts one’s ability to comprehend language, but it leaves one’s ability to produce words intact.

1. amygdala
2. Broca’s Area
3. Wernicke’s Area
4. occipital lobe

#### Q3

A(n) ________ uses magnetic fields to create pictures of a given tissue.

1. EEG
2. MRI
3. PET scan
4. CT scan

#### Q4

Which of the following is not a structure of the forebrain?

1. thalamus
2. hippocampus
3. amygdala
4. substantia nigra

### Critical Thinking Questions

#### Q5

Before the advent of modern imaging techniques, scientists and clinicians relied on autopsies of people who suffered brain injury with resultant change in behavior to determine how different areas of the brain were affected. What are some of the limitations associated with this kind of approach?

#### Q6

Which of the techniques discussed would be viable options for you to determine how activity in the reticular formation is related to sleep and wakefulness? Why?

### Personal Application Questions

#### Q7

You read about H. M.’s memory deficits following the bilateral removal of his hippocampus and amygdala. Have you encountered a character in a book, television program, or movie that suffered memory deficits? How was that character similar to and different from H. M.?

### Solution

D

C

B

D

#### S5

The same limitations associated with any case study would apply here. In addition, it is possible that the damage caused changes in other areas of the brain, which might contribute to the behavioral deficits. Such changes would not necessarily be obvious to someone performing an autopsy, as they may be functional in nature, rather than structural.

#### S6

The most viable techniques are fMRI and PET because of their ability to provide information about brain activity and structure simultaneously.

## 3.5: The Endocrine System

The endocrine system consists of a series of glands that produce chemical substances known as hormones. Like neurotransmitters, hormones are chemical messengers that must bind to a receptor in order to send their signal. However, unlike neurotransmitters, which are released in close proximity to cells with their receptors, hormones are secreted into the bloodstream and travel throughout the body, affecting any cells that contain receptors for them.

### Review Questions

#### Q1

The two major hormones secreted from the pancreas are:

1. estrogen and progesterone
2. norepinephrine and epinephrine
3. thyroxine and oxytocin
4. glucagon and insulin

#### Q2

The ________ secretes messenger hormones that direct the function of the rest of the endocrine glands.

1. ovary
2. thyroid
3. pituitary
4. pancreas

#### Q3

The ________ gland secretes epinephrine.

2. thyroid
3. pituitary
4. master

#### Q4

The ________ secretes hormones that regulate the body’s fluid levels.

2. pituitary
3. testis
4. thyroid

### Critical Thinking Questions

#### Q5

Hormone secretion is often regulated through a negative feedback mechanism, which means that once a hormone is secreted it will cause the hypothalamus and pituitary to shut down the production of signals necessary to secrete the hormone in the first place. Most oral contraceptives are made of small doses of estrogen and/or progesterone. Why would this be an effective means of contraception?

#### Q6

Chemical messengers are used in both the nervous system and the endocrine system. What properties do these two systems share? What properties are different? Which one would be faster? Which one would result in long-lasting changes?

### Personal Application Questions

#### Q7

Given the negative health consequences associated with the use of anabolic steroids, what kinds of considerations might be involved in a person’s decision to use them?

### Solution

D

C

A

B

#### S5

The introduction of relatively low, yet constant, levels of gonadal hormones places the hypothalamus and pituitary under inhibition via negative feedback mechanisms. This prevents the alterations in both estrogen and progesterone concentrations that are necessary for successful ovulation and implantation.

#### S6

Both systems involve chemical messengers that must interact with receptors in order to have an effect. The relative proximity of the release site and target tissue varies dramatically between the two systems. In neurotransmission, reuptake and enzymatic breakdown immediately clear the synapse. Metabolism of hormones must occur in the liver. Therefore, while neurotransmission is much more rapid in signaling information, hormonal signaling can persist for quite some time as the concentrations of the hormone in the bloodstream vary gradually over time.