Biology: Nervous System 2

Biology The Nervous System

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!Part 2

Nervous SystemYour central

nervous system is your brain

and spinal cord. The brain controls

behavior, and the spinal

cord transmits messages

between the brain and the

body.

Nervous SystemYour peripheral nervous system is the network of nerve cells that extend

throughout your body. It has a

somatic division (voluntary

movements) and an autonomic

division (involuntary movements).

Nervous SystemYour peripheral nervous system is the network of nerve cells that extend

throughout your body. It has a

somatic division (voluntary

movements) and an autonomic

division (involuntary movements).

Somatic Division: - Voluntary muscle movements - Communication between sensory

organs and the brain

Sensory Organs: Ears (hearing) Eyes (sight) Skin (feeling) Nose (smell) Tongue (taste)

Nervous SystemYour peripheral nervous system is the network of nerve cells that extend

throughout your body. It has a

somatic division (voluntary

movements) and an autonomic

division (involuntary movements).

Autonomic Division: - Involuntary movements (like breathing

and blood pressure) - Controls “fight or flight” response:

when the body is responding to a threat

Brain Structure

Brain Structure• The “Old Brain” is the part of the brain that controls eating,

breathing, and sleeping. It is common to all vertebrates. • The evolution of the “old brain” dates back 500 million years.

• “The Midbrain” controls vision, hearing, motor control, alertness, and temperature regulation.

Brain Structure

• The “New Brain” is the cerebral cortex: the outer layer of nerve tissue in our brains. It controls memory, attention,

perceptual awareness, thought, language, and consciousness. The cerebral cortex is the part of the brain that allows us to reason.

Brain StructureDifferent lobes of the cerebral cortex are involved in different bodily functions. A PET (positron emission tomography) scan shows us which parts of the brain are active during different

daily activities.

Brain Structure

Frontal Lobe: • Controls the body’s dopamine system

• The function of the frontal lobe involves the ability to recognize future consequences, the choice between good and bad actions, the differentiation between bad/good/

better/best, the suppression of socially unacceptable behavior, and the ability to determine similarities and

differences. It also helps us retain long term memories. !!!

Brain Structure

Parietal Lobe: • Processes information derived from our senses. It

allows us to recognize objects by touch alone, manipulate objects with our hands, and understand how objects are positioned in space around us (spatial understanding). It also allows us to understand and manipulate numbers.

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Brain Structure

Temporal Lobe: • Involved in smell, sound, vision, and memory. • Allows us to form, store, and retrieve long-term

memories. It includes the auditory association area, which allows us to process sounds and comprehend speech. This lobe gives us the ability to recognize and

name people and objects. !!!!

Brain Structure

Occipital Lobe: • The primary visual processing center of the brain, the

occipital lobe allows you to process and understand what you are seeing.

• This lobe allows us to differentiate between different colors and perceive motion.

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Behavioral GeneticsThe study of the effects of heredity on behavior.

To what extent are our abilities, personality traits, sexual orientations, sociability, and psychological disorders determined by genes inherited from our parents?

Behavioral GeneticsNature? (Genetics) or Nurture? (Environment)

Study: Men who carry one or two extra copies of a gene called allele 334 often

behave differently in relationships than men who lack this gene variant. Men with an extra copy of the gene felt a weaker, less permanent attachment to their partners,

and were more likely to be unfaithful. Men who had two copies of allele 334 were also

twice as likely to have had a marital or relationship crisis in the past year than

those who lacked the gene variant. (Karolinska Medical Institute, Stockholm).

Behavioral GeneticsNature? (Genetics) or Nurture? (Environment)

Study: Novelty-seeking behavior (impulsive decision-making, the need to explore, lack

of organization) is related to the

presence of a certain gene in the body, and is highly inheritable.

(Golimbet et al., 2007).

Behavioral GeneticsNature? (Genetics) or Nurture? (Environment)

Study: 1,252,387 genetic markers were tested for association with

personality traits. The results indicated that only 1% of genetic variants significantly contribute to

personality variation. This indicates that individual common

genetic variants do not significantly contribute to personality trait variation.

(Verweij et al., 2010)

Behavioral GeneticsNature? (Genetics) or Nurture? (Environment)

Twin Studies are used to help us answer the question of “nature vs. nurture.”

Behavioral GeneticsNature? (Genetics) or Nurture? (Environment)

Look at pair 1: one sibling is

adopted. !

Look at pair 2: Identical twins.

Imagine that they were separated at birth and raised

in different families.

Pair-ShareDo you think a Twin Study is a reliable way to

test whether our behavior is determined more by nature (genetics) or nurture (environment)?

Why or why not?

Pair-ShareDo you think you share any personality traits

with your parents or grandparents?