Week 3 - Biology and Behaviour

What are neurons?

Specialised nerve cells that transmit information throughout the nervous system

How do neurons communicate?

Electrically within the neuron (action potentials) and chemically between neurons (neurotransmitters crossing the synaptic cleft).

What are dendrites?

Receive incoming signals from other neurons

What is a cell body?

Contains nucleus; integrates incoming information

What is an axon?

Carries electrical impulses away from the cell body

What are terminal buttons?

Release neurotransmitters into the synaptic cleft

What is the direction of neural signaling?

Dendrites → Cell body → Axon → Terminal buttons → Synapse

What is the myelin sheath?

A white, fatty insulating layer around axons

What is its function?

Speeds up neural transmission and protects the axon

What are sensory neruons?

Carry information from receptors to the CNS (afferent)

What are motor neurons?

Carry commands from CNS to muscles/glands (efferent)

What are interneurons?

Connect neurons to each other; most common type

What is the all-or-none principle?

A neuron fires completely or not at all once threshold is reached

How does stimulus strength affect firing?

Stronger stimuli increase firing rate, not size

What is the synaptic cleft?

The tiny gap between neurons where chemical transmission occurs

What happens during synaptic transmission?

Action potential → Vesicles release neurotransmitters → Bind to receptors → Produce graded potential

What is glutamate?

Major excitatory neurotransmitter; involved in learning & memory. Excess linked to seizures, Huntington’s, Alzheimer’s.

What is GABA?

Major inhibitory neurotransmitter; regulates anxiety. Low levels linked to seizures, insomnia.

What is acetylcholine?

Involved in learning, memory, muscle movement. Low levels linked to Alzheimer’s.

What is dopamine?

Movement, reward, emotion. Low = Parkinson’s; high = schizophrenia.

What is serotonin?

Mood, sleep, appetite. Low levels linked to depression.

What are endorphins?

Natural painkillers; elevate mood.

What does the pituitary gland do?

“Master gland”; regulates other glands; growth hormone.

What does the thyroid gland do?

Controls metabolism; low activity → fatigue, depression.

What do the adrenal glands do?

Release adrenaline & cortisol; stress response.

What does the pancreas do?

Regulate blood sugar via insulin

What do the gonads do?

Produce s3x hormones (testosterone, estrogen).

What is the CNS?

Brain + spinal cord.

What is the PNS?

All nerves outside CNS.

What is the somatic system?

Voluntary movement; sensory input.

What is the autonomic system?

Involuntary functions (heart rate, digestion)

What is the sympathetic system?

Fight-or-flight activation

What is the parasympathetic system?

Rest-and-digest restoration

How does the sympathetic system support fight-or-flight?

Increases heart rate, dilates pupils, stops digestion.

How does the parasympathetic system restore balance?

Slows heart rate, resumes digestion, conserves energy.

How did the CNS evolve?

Began with simple reflexive spinal cords → hindbrain → midbrain → forebrain → cortex

What does the medulla do?

Controls heartbeat, breathing

What does the cerebellum do?

Movement coordination, balance, learning

What does the reticular formation do?

Arousal, consciousness

What does the hypothalamus do?

Homeostasis; hunger, temperature, hormones

What does the thalamus do?

Sensory relay station

What does the amygdala do?

Fear, emotion, threat detection

What does the hippocampus do?

Formation of new memories

What do the basal ganglia do?

Movement control; automatic behaviours

What are the four lobes?

Frontal, parietal, occipital, temporal

What are primary areas?

Process raw sensory input or initiate movement

What are associaton areas?

Higher-order thinking, planning, perception

What is the motor cortex?

Controls voluntary movement

What is the somatosensory cortex?

Processes touch, pressure, pain, temperature

What is cerebral lateralisation?

Left hemisphere: language, logic. Right hemisphere: spatial, visual processing.

What do split-brain studies show?

Each hemisphere processes information independently when corpus callosum is severed.

What is heredity?

Transmission of traits from parents to offspring.

What is behavioural genetics?

Study of genetic influences on behaviour.

What is DNA?

Double‑helix molecule containing genetic code.

What are genes and chromosomes?

Genes = units of heredity; chromosomes = strands of DNA containing genes.

How do twin studies inform nature vs nurture?

Compare identical vs fraternal twins to estimate genetic influence.

How do adoption studies inform nature vs nurture?

Compare adopted children to biological vs adoptive parents.

Frontal lobe

Front of the brain, behind the forehead; involves in planning, decision-making, movement, personality

Parietal lobe

Upper middle region, behind the frontal lobe; processes touch, spatial awareness, body sensations

Occipital lobe

Back of the brain; primary centre for vision

Temporal lobe

Sides of the brain, near the temples; involves in hearing, memory, language, and emotion