Human Phys Chapter 8
Consciousness
Q: What does an EEG measure, and what do amplitude and frequency represent?
A: An EEG measures electrical activity in the brain. Amplitude represents the strength of brain signals, while frequency represents the speed of oscillations.
Q: Define circadian rhythm and identify the role of the SCN of the hypothalamus.
A: Circadian rhythm is the body's internal clock regulating sleep-wake cycles. The suprachiasmatic nucleus (SCN) controls wakefulness by influencing melatonin release and other signals.
Q: Where is orexin produced, and what is its role in wakefulness?
A: Orexin is produced in the hypothalamus and promotes wakefulness by stimulating brain regions associated with alertness.
Q: What is the reticular activating system (RAS), and how does it maintain wakefulness?
A: The RAS is a network in the brainstem that regulates wakefulness using neurotransmitters like norepinephrine, dopamine, serotonin, and histamine.
Q: What EEG rhythms are seen during wakefulness?
A: Beta (active thinking) and alpha (relaxed but awake) waves.
Sleep
Q: How does the VLPO of the hypothalamus contribute to sleep?
A: The ventrolateral preoptic nucleus (VLPO) inhibits wake-promoting neurons, facilitating sleep.
Q: What is the role of the pineal gland in sleep?
A: The pineal gland produces melatonin, which promotes sleepiness.
Q: How does the RAS contribute to sleep?
A: The RAS reduces activity in sleep by decreasing norepinephrine and serotonin levels.
Q: What are the phases of sleep, and what EEG patterns are present?
A:
NREM 1: Light sleep, theta waves
NREM 2: Deeper sleep, sleep spindles & K-complexes
NREM 3: Deep sleep, delta waves
REM: Dreaming, beta-like waves
Q: What are the physiological reasons for sleep?
A: Restoration, memory consolidation, immune function, energy conservation.
Q: How does a person transition between wakefulness and sleep?
A: The SCN, VLPO, RAS, orexin, and neurotransmitters regulate the shift between wake and sleep states.
Limbic System—General
Q: What is the limbic system, and what behaviors is it involved in?
A: The limbic system is a network of brain structures controlling emotion, motivation, and memory.
Q: Define motivation and differentiate intrinsic vs. extrinsic motivation.
A: Motivation is the drive to act.
Intrinsic: Internal rewards (e.g., enjoyment)
Extrinsic: External rewards (e.g., money)
Q: What is dopamine’s role in motivation and reward?
A: Dopamine in the mesolimbic pathway reinforces rewarding behaviors.
Limbic System—Memory & Learning
Q: Define learning.
A: Learning is the process of acquiring new knowledge or skills.
Q: Differentiate declarative vs. procedural memory.
A:
Declarative: Facts and events (e.g., remembering a date).
Procedural: Skills and habits (e.g., riding a bike).
Q: Differentiate short-term vs. long-term memory.
A:
Short-term: Temporary storage (~seconds to minutes).
Long-term: Permanent storage after consolidation.
Q: What are the roles of the hippocampus and prefrontal cortex in memory?
A:
Hippocampus: Formation of declarative memories.
Prefrontal cortex: Memory retrieval and decision-making.
Q: What is memory consolidation, and how does long-term potentiation (LTP) contribute?
A:
Memory consolidation is the strengthening of memories over time.
LTP enhances synaptic strength, making memories more stable.