Biological Psychology: Nervous System, Neurotransmitters, and Genetics

Biological Psychology

Autonomic Nervous System: Sympathetic vs. Parasympathetic

The autonomic nervous system (ANS) regulates involuntary physiological processes. It is divided into the sympathetic and parasympathetic branches, each with distinct functions.

• Sympathetic Nervous System: Prepares the body for 'fight or flight' responses. Increases heart rate, dilates pupils, inhibits digestion, and mobilizes energy.

• Parasympathetic Nervous System: Promotes 'rest and digest' activities. Slows heart rate, constricts pupils, stimulates digestion, and conserves energy.

• When Each is Active: The sympathetic system is activated during stress or emergencies, while the parasympathetic system dominates during restful states.

Example: When you encounter a threat, your sympathetic system increases your heart rate. After the threat passes, the parasympathetic system calms your body.

Natural Selection in Psychology

Natural selection is a process where traits that enhance survival and reproduction become more common in a population over generations.

• Definition: Traits that improve an organism's chances of survival and reproduction are more likely to be passed on.

• Example: Birds with beaks better suited to available food sources are more likely to survive and reproduce.

Agonists and Antagonists in Neurotransmission

Neurotransmitters are chemicals that transmit signals across synapses in the nervous system. Agonists and antagonists are substances that affect neurotransmitter activity.

• Agonists: Mimic or enhance the action of a neurotransmitter. They bind to receptors and activate them.

• Antagonists: Block or inhibit the action of a neurotransmitter. They bind to receptors but do not activate them, preventing the neurotransmitter from binding.

Example: Morphine is an agonist for endorphin receptors; naloxone is an antagonist that blocks opioid receptors.

Purpose and Function of Brain Areas

The brain is divided into specialized regions, each responsible for different functions.

• Cerebral Cortex: Involved in higher-order functions like reasoning, language, and perception.

• Hippocampus: Essential for memory formation.

• Amygdala: Processes emotions, especially fear and pleasure.

• Brainstem: Controls basic life functions such as breathing and heart rate.

Example: Damage to the hippocampus can result in difficulty forming new memories.

Genetic Makeup of Humans

Human traits are influenced by genes, which are segments of DNA inherited from parents.

• Genes: Units of heredity that encode instructions for proteins.

• Genotype: The genetic makeup of an individual.

• Phenotype: Observable characteristics resulting from the interaction of genotype and environment.

Example: Eye color is determined by specific gene variants inherited from parents.

Adrenal Gland: Purpose and Function

The adrenal glands are endocrine glands located above the kidneys. They produce hormones that help regulate metabolism, immune response, and stress.

• Adrenal Medulla: Secretes adrenaline (epinephrine) and noradrenaline (norepinephrine) during stress (fight or flight response).

• Adrenal Cortex: Produces corticosteroids, which regulate metabolism and immune response.

Example: During a stressful event, the adrenal glands release adrenaline, increasing heart rate and energy availability.