Psychology Chapter 3: The Biological Component

Neurons

• Neurons are specialized cells that transmit sensory information, process data within the CNS, and relay commands to muscles and organs.
• Types of neurons:
  • Motor neurons: transmit commands to muscles and organs.
  • Sensory neurons: carry information from the body and environment to the brain and spinal cord.
  • Interneurons: connect neurons within the CNS, facilitating communication.

Cell Membrane and Ion Movement

• Polarization refers to the electrical charge difference across the neuron's membrane, critical for action potentials.
• Resting potential: the steady state of difference in charge when a neuron is inactive.
• Ions (Na+, K+, Cl-, A-) influence neuron activity through:
  • Force of diffusion: movement from areas of high to low concentration.
  • Electrostatic pressure: attraction to opposite charges and repulsion from similar charges.
• The sodium-potassium pump maintains ion balance, moving sodium out and potassium into the cell.

Action Potential

• Depolarization occurs when the membrane potential becomes less negative, potentially triggering an action potential.
• Action potential follows an all-or-none law and is nondecremental, maintaining strength as it travels down the axon.
• Hyperpolarization is an increase in charge inside the neuron, often due to chloride influx or potassium efflux.

Synapse and Neurotransmission

• Synapses are fluid-filled gaps between neurons where neurotransmission occurs.
• Neurotransmitters are chemicals that transmit signals across the synapse, influencing the firing of postsynaptic neurons.
• Excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs) alter neuron firing probabilities.
• Drugs can act as agonists (enhancing receptor activity) or antagonists (reducing receptor activity).

Organization of the Nervous System

• The nervous system is divided into the Central Nervous System (CNS) and Peripheral Nervous System (PNS).
• CNS comprises the brain and spinal cord; PNS includes all nerves outside the CNS.
• The PNS is further divided into the somatic nervous system (voluntary functions) and autonomic nervous system (involuntary functions).
• In the CNS, afferent pathways carry signals toward the brain while efferent pathways transmit signals from the brain.

Brain Structure

• The brain consists of three primary regions:
  • Hindbrain: controls vital functions and movement coordination.
  • Midbrain: oversees reflex actions and voluntary movements.
  • Forebrain: involved in complex cognitive functions and processes.

Key Brain Components

• Medulla: regulates heart rate, circulation, and respiration.
• Pons: relays signals and coordinates functions between various brain levels.
• Cerebellum: important for balance, coordination, and procedural memory (motor skills).
• Thalamus: acts as a sensory information relay station and filters sensory data.
• Hypothalamus: regulates autonomic functions, hormone secretion, and homeostasis.

Hemispheric Lateralization

• Each brain hemisphere specializes in different functions:
  • Right Hemisphere: associated with emotions, intuition, aesthetics, and nonverbal processing.
  • Left Hemisphere: involved in analytical thinking, verbal communication, and logic.
• The corpus callosum is the brain structure that connects and facilitates communication between the two hemispheres.

Endocrine System

• Comprises glands that release hormones, acting as a secondary control system for body functions.
• Major glands:
  • Pituitary: known as the “director” of hormonal regulation.
  • Thyroid: regulates metabolic rate.
  • Adrenal: involved in metabolism of salts and carbohydrates.
  • Pancreas: manages blood sugar levels.
• The hypothalamus integrates the nervous and endocrine systems, controlling hormone release.

Research Techniques in Neuroscience

• Various methods are used to study brain function:
  • CT (Computed Tomography): provides 2D images of the brain using X-rays.
  • MRI (Magnetic Resonance Imaging): offers high-resolution images of brain soft tissues using magnetic fields.
  • fMRI (Functional MRI): measures brain activity by detecting changes in blood flow.
  • PET (Positron Emission Tomography): tracks radioactive compounds in the bloodstream to visualize active brain areas.
  • EEG (Electroencephalography): records electrical activity via electrodes, providing excellent temporal resolution.

Important Concepts

• Plasticity: the brain’s ability to form new connections and adapt after injuries.
• Aphasia: a language disorder affecting processing and production.
• Mirror neurons: involved in understanding others' actions and intentions.

This quiz focuses on Chapter 3 of the psychology textbook, which explores the biological component of the nervous and endocrine systems. It covers topics such as neuron structure, electrical and chemical signal transmission, and hemispheric lateralization. Test your understanding of the fundamental concepts surrounding how our body communicates at a cellular level.