Notes
Neurons and neurotransmitters
- Neurons receive signals with dendrites and send them along the axon. Myelin speeds transmission. An action potential is all-or-none.
- Neurons communicate across the synapse with neurotransmitters. Key ones: acetylcholine (muscles, memory), dopamine (reward, movement), serotonin (mood, sleep), GABA (inhibits), glutamate (excites), endorphins (pain relief).
Nervous system and brain
- CNS = brain and spinal cord; PNS = everything else. The autonomic system has sympathetic ("fight or flight") and parasympathetic ("rest and digest") parts.
- Brain: medulla (breathing, heartbeat), cerebellum (balance), thalamus (relay), hypothalamus (hunger, temperature), amygdala (fear), hippocampus (memory). Cortex lobes: frontal, parietal, temporal, occipital.
- Neuroplasticity is the brain's ability to change with experience.
Endocrine system
- Glands release hormones into the blood. The pituitary controls other glands; adrenal glands release adrenaline and cortisol during stress.
Topics in this unit
Each topic has its own short notes and practice.
Practice
Signals are received by dendrites, pass through the cell body and travel down the axon.
The parasympathetic system returns the body to a calm state.
GABA reduces neural activity.
The hippocampus is central to forming new memories.
Blocking reuptake leaves more neurotransmitter in the gap, boosting its effect.
Both sides work together, linked by the corpus callosum.
Free response
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Free-response question
Leo is walking home when a car suddenly swerves toward him. He jumps back onto the sidewalk, his heart pounds and his breathing quickens. A few minutes later he feels calmer.
(a) Name the division of the autonomic nervous system that caused his heart to pound and breathing to quicken.
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The sympathetic nervous system, which prepares the body for fight or flight.
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(b) Identify one hormone and the gland that releases it during this event.
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Adrenaline (epinephrine) is released by the adrenal glands, increasing heart rate and energy.
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(c) Explain how his body returned to calm and name the brain structure that helps process fear.
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The parasympathetic nervous system slowed his heart rate and breathing. The amygdala is involved in processing fear.
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