Brain

Question 1

Division of Nervous System

Answer 1

• CNS (brain and spinal cord) and PNS (nervous tissue and fibers).
• PNS: Somatic NS (voluntary, conscious control) and Autonomic NS (involuntary, automatic control).
• ANS: Sympathetic NS and Parasympathetic NS.
• Sympathetic Nervous System: Activated by stress; releases epinephrine hormone into bloodstream, increases HR, redirects blood to muscles of locomotion and decreases digestion, increases blood glucose, relaxes/dilates bronchi, dilates eyes for max light intake.
• Parasympathetic Nervous System: Conserves energy, associated with resting and sleeping, and regulated by acetylcholine; reduces HR, stimulates exocrine secretion and digestion, constricts bronchi, constricts pupils.

Question 2

Brain Structures

Answer 2

• Hindbrain + Midbrain = Brain Stem, (Primitive Brain).
• Hindbrain (Rhombencephalon): Medulla Oblongata (Lower structure, regulates vital functions such as breathing, heart rate, digestion); Pons (Above medulla, contains sensory and motor pathways between cortex and medulla); Cerebellum (Top of hindbrain and behind pons, motor coordination and maintains posture/balance). Myelencephalon becomes medulla; metencephalon becomes pons and cerebellum.
• Midbrain (Mesencephalon): Above hindbrain; associated with involuntary reflexes responses triggered by visual sensory stimuli (superior colliculus) and auditory sensory stimuli (inferior colliculus).
• Forebrain (Prosencephalon): Above midbrain; associated with complex perceptual, cognitive, and behavioral processes (modern brain). Telencephalon forms cerebral cortex, basal ganglia, and limbic system; diencephalon forms thalamus, hypothalamus, posterior pituitary gland, and pineal gland.

Question 3

Parts of Forebrain

Answer 3

• Thalamus: Relay station for sensory information, excluding smell; sorts and transmits sensory information to appropriate areas of cerebral cortex.
• Hypothalamus: Serves homeostatic functions (regulates metabolism, temperature, water balance/osmolarity) and controls drives (hunger/appetite/satiety, thirst, sexual/aggressive behaviors, sleep-wake cycle).
• Posterior Pituitary Gland: Houses axonal projections from hypothalamus and is site of release of hypothalamic hormones ADH/vasopressin and oxytocin.
• Pineal Gland: Releases melatonin to regulate circadian rhythms and is controlled by hypothalamus, which receives direct signals from retina for coordination with sunlight.
• Basal Ganglia: Coordinates smooth muscle movements and steady posture.
• Limbic System: Septal Nuclei (primary pleasure centers and addiction); Amygdala (regulates defensive and aggressive behaviors such as rage and fear); Hippocampus (associated with learning processes and long-term memory formation, communicates with rest of limbic system via fornix); Anterior Cingulate Cortex (regulates impulse control, decision-making, and motivation).
• Cerebral Cortex: Frontal Lobe (prefrontal cortex is an association area that manages executive and cognitive functions, personality expression, and decision-making; primary motor cortex is a projection area that initiates voluntary muscle movements; and Broca’s area associated with speech production). Parietal Lobe (central region associated with spatial planning and manipulation and orientation in 3D space, primary somatosensory cortex is a projection area that receives sensory signals for touch, pressure, temperature, pain). Occipital Lobes (visual cortex processes visual input). Temporal Lobes (auditory cortex processes sound, Wernicke’s area associated with language reception and comprehension).

Question 4

Cerebral Hemispheres and Laterality

Answer 4

• Contralateral Communication: Between opposite sides of the body, such as motor function (right hemisphere activates movements on left side of body).
• Ipsilateral Communication: Between the same side of the body, such as hearing.
• Dominant Hemisphere: Usually left, primarily analytic in function (language, logic, math).
• Nondominant Hemisphere: Usually right, associated with intuition, creativity, music cognition, spatial processing, emotional tone of language, processing of visual/auditory cues to recognize moods.

Question 5

Agonists and Antagonists

Answer 5

• Agonist: Drug that mimics the action of a particular neurotransmitter.
• Antagonist: Drug that blocks the action of a particular neurotransmitter.

Question 6

Neurotransmitters

Answer 6

• Acetylcholine: Used by efferent limb of somatic nervous system and parasympathetic nervous system. In CNS, linked to attention and arousal and memory storage in hippocampus.
• Catecholamines: Epinephrine and norepinephrine control alertness and wakefulness and fight-or-flight response of sympathetic nervous system (high norepinephrine levels associated with anxiety/mania, low levels associated with depression); Dopamine smooths movements and maintain stability in basal ganglia (high dopamine levels associated with schizophrenia, low levels associated with Parkinson’s disease).
• Serotonin: Regulates mood, eating, sleeping, dreaming (high serotonin levels produce manic states, low levels produce depression).
• GABA, Glycine, Glutamate: GABA and glycine function as inhibitory neurotransmitters, and glutamate functions as excitatory neurotransmitter.
• Endorphins: Natural painkillers.

Question 7

Genetic Studies of Behavior

Answer 7

• Family Studies: Compare rates of trait in family members to rates in unrelated individuals or general population; limited because families share genetics and environment.
• Twin Studies: Compare concordance rates for trait between monozygotic identical twins and dizygotic fraternal twins; assumes same environment so differences between MZ and DZ twins reflect genetic factors.
• Adoption Studies: Compare similarities between relatives and adopted child to similarities between adoptive relatives and adopted child; both genetics and environment vary.

Question 8

Development

Answer 8

• Gross motor skills progress into fine motor skills in a head-to-toe and in-to-out order. Rooting reflex (turning head to direction of stimulus touching cheek for finding nipple), Moro reflex (arms fling out and slowly retract and crying in response to abrupt head movements), Babinski reflex (toes spread when sole of foot stimulated), grasping reflex.
• Social skills develop from being parent-oriented to self-oriented to other-oriented. Stranger anxiety and separation anxiety, parallel play (playing with each other without influencing each other’s behavior), teenagers become self-sufficient and rebel, then cross-gender friendships and sexual relationships develop.