lecture 4 - biopsychology - psyc 1101

Neurotransmitter: Acetylcholine (ACh)

Enables muscle action, learning, and memory.

Acetylcholine (ACh) — Examples of Imbalances

With Alzheimer's disease, ACh-producing neurons deteriorate.

Neurotransmitter: Dopamine

Influences movement, learning, attention, and emotion.

Dopamine — Examples of Imbalances

Oversupply linked to schizophrenia. Undersupply linked to tremors and decreased mobility in Parkinson's disease.

Neurotransmitter: Serotonin

Affects mood, hunger, sleep, and arousal.

Serotonin — Examples of Imbalances

Undersupply linked to depression. Some antidepressant drugs raise serotonin levels.

Neurotransmitter: Norepinephrine

Helps control alertness and arousal.

Norepinephrine — Examples of Imbalances

Undersupply can depress mood.

Neurotransmitter: GABA (gamma-aminobutyric acid)

A major inhibitory neurotransmitter.

GABA (gamma-aminobutyric acid) — Examples of Imbalances

Undersupply linked to seizures, tremors, and insomnia.

Neurotransmitter: Glutamate

A major excitatory neurotransmitter; involved in memory.

Glutamate — Examples of Imbalances

Oversupply can overstimulate the brain, producing migraines or seizures.

Main components of the Nervous System

Brain, spinal cord, nerves, and support (glial) cells

Central Nervous System (CNS) components

Brain and spinal cord

Peripheral Nervous System (PNS) function

Connects the rest of the body to the brain and spinal cord

Two main subdivisions of the Peripheral Nervous System (PNS)

Somatic Nervous System and Autonomic Nervous System

Somatic Nervous System function

Controls voluntary, conscious actions (e.g., walking, raising your hand)

Autonomic Nervous System function

Controls involuntary, unconscious actions (e.g., breathing, digestion, heartbeat)

Two main subdivisions of the Autonomic Nervous System

Sympathetic Nervous System and Parasympathetic Nervous System

Sympathetic Nervous System function

Prepares the body for stressful situations, activates physiological arousal, and triggers fight-or-flight

Parasympathetic Nervous System function

Calms the body back to baseline, diminishes physiological arousal, and is active during rest (ataraxia)

Sympathetic Nervous System physiological responses

Dilates pupils, inhibits salivation, increases heart rate, dilates bronchi, inhibits digestion, and inhibits bladder contraction

Parasympathetic Nervous System physiological responses

Constricts pupils, stimulates salivation, slows heart rate, constricts bronchi, stimulates digestion, and contracts bladder

Neuron / Nerve cell definition

Cells that transmit information throughout the nervous system between the body and brain

Dendrites function

Branches that receive chemical messages from other neurons

Soma (Cell body) function

The main body of the neuron containing the nucleus and cellular machinery

Nucleus function

Enclosed structure inside the soma that contains the neuron's genetic material (DNA)

Axon function

Long tail extending from the soma that conducts electrical signals to the axon terminals

Myelin sheath function

Fatty coating that coats and insulates the axon to allow faster signal processing

Axon terminals function

Endings of the axon that release neurotransmitters across the gap to neighboring neurons

Synapse function

The microscopic space between the sending neuron's axon and receiving neuron's dendrites

Neurotransmitters definition

Chemicals that carry signals across the synapse from one cell to another

Receptor sites function

Proteins on receiving dendrites that selectively accept specific neurotransmitters

Reuptake process

Neurotransmitters that do not land on receptor sites are reabsorbed by the sender neuron

Neuron electrical charge during Resting Potential

Negative electrical charge (around -70 mV)

Neuron electrical charge during Action Potential

Positive electrical charge (peaking around plus 30 mV)

Voltage shift needed to trigger an Action Potential

A change in membrane voltage from negative baseline to the positive threshold of excitation (around -55 mV)

All-or-Nothing Principle

A neuron either fires completely or not at all; its speed, strength, and duration are unaffected by stimulus strength beyond the threshold