EXAM 3 GUIDE QUESTIONS

Question 1

What are the three physical qualities of sound and how do they pertain to the three perceptual qualities of sound?

Answer 1

The three physical qualities are: Amplitude → perceived as loudness; Frequency → perceived as pitch; Complexity → perceived as timbre (tone quality)

Question 2

Describe the pathway of auditory information from the auditory nerve, all the way to the primary auditory cortex.

Answer 2

Sound → eardrum → ossicles (malleus, incus, stapes) → oval window → cochlea → hair cells (organ of Corti) → auditory nerve (cranial nerve VIII) → cochlear nuclei (medulla) → superior olives (pons) → inferior colliculus (midbrain) → medial geniculate nucleus (thalamus) → primary auditory cortex (temporal lobe)

Question 3

Describe the anatomy of the organ of Corti.

Answer 3

The organ of Corti is the sound receptor inside the cochlea. It contains: The basilar membrane (where the hair cells sit); Hair cells (inner and outer) that convert sound vibrations into neural signals; The tectorial membrane, which lies over the hair cells and bends them when sound waves move the fluid.

Question 4

Describe the role of the three structures involved with sound localization.

Answer 4

SIA” = Sound In Action

S → Superior Olivary Complex → Starts comparing sounds (time + loudness differences)

I → Inferior Colliculus → Integrates the info to make a 3D sound map

A → Auditory Cortex → Analyzes and decides where the sound is

Question 5

Describe the function of the different sensory receptors in the skin.

Answer 5

Free nerve endings – detect pain and temperature; Pacinian corpuscles – detect deep pressure and vibration; Merkel’s disks – detect steady pressure and texture; Meissner’s corpuscles – detect light touch; Ruffini endings – detect skin stretch.

Question 6

What are the different regions associated with pain?

Answer 6

Anterior cingulate cortex (ACC) – emotional reaction to pain; Primary and secondary somatosensory cortex – location and intensity of pain; Prefrontal cortex – long-term emotional suffering and attention to pain; Thalamus – relays pain signals to the cortex.

Question 7

Describe the pain circuit associated with the periaqueductal grey (PAG).

Answer 7

The periaqueductal grey (PAG) in the midbrain can suppress pain. It activates neurons in the raphe nuclei (in the medulla), which release serotonin that excites inhibitory interneurons in the spinal cord — these inhibit pain signals traveling upward to the brain.

Question 8

What is neuropathic pain?

Answer 8

Neuropathic pain is chronic pain caused by damage or malfunction in the nervous system itself, not by an external injury. The brain continues to receive pain signals even when there’s no real damage.

Question 9

Describe the role of the different structures in the brain that are involved with motor control.

Answer 9

Primary motor cortex – sends commands to muscles; Premotor cortex – plans movements; Supplementary motor area – organizes sequences of movement; Basal ganglia – initiate and control voluntary movement; Cerebellum – fine-tunes movement, balance, coordination.

Question 10

What is target coding?

Answer 10

Target coding means the brain codes movement based on the desired final position (target) rather than the specific muscles used to reach it.

Question 11

What are the differences between antagonistic and synergistic muscle groups?

Answer 11

Antagonistic muscles – work in opposite directions (e.g., biceps and triceps); Synergistic muscles – work together to perform the same movement (e.g., biceps and brachialis during arm flexion).

Question 12

What are the similarities and differences between the ventromedial and dorsolateral motor pathways?

Answer 12

Pathway Function Control Type: Dorsolateral Fine, precise, independent limb movements Contralateral (opposite side); Ventromedial Posture, balance, whole-body movements Bilateral (both sides); Both pathways carry motor commands from the brain to the spinal cord.

Question 13

Describe the monosynaptic, di-synaptic, and polysynaptic reflex pathways.

Answer 13

Monosynaptic reflex: One synapse between sensory and motor neuron. Example: Patellar (knee-jerk) reflex; Receptor: Muscle spindle; Effect: Causes the stretched muscle to contract. Di-synaptic reflex: Involves one interneuron; Receptor: Golgi tendon organ; Effect: Prevents excessive muscle tension by relaxing the muscle. Polysynaptic reflex: Multiple interneurons involved; Example: Withdrawal reflex; Receptor: Nociceptor (pain receptor); Effect: Pulls limb away from painful stimulus.

Question 14

Describe the timeline of events that result in the development of the neural tube.

Answer 14

Neural plate forms on the embryo (around day 18). Edges of the plate fold up to form the neural groove. The folds meet and fuse to form the neural tube (around day 22). The tube later becomes the central nervous system (brain and spinal cord).

Question 15

What does the neural crest develop into?

Answer 15

The neural crest develops into: Peripheral nervous system neurons and glia; Melanocytes (pigment cells); Parts of the skull and face; Adrenal medulla cells.

Question 16

Describe the factors associated with synaptogenesis.

Answer 16

Synaptogenesis (formation of synapses) is influenced by: Genetic programming; Chemical signals (neurotrophins) guiding connections; Neural activity (experience strengthens useful connections); Environmental stimulation.

Question 17

Describe the revised chemoaffinity hypothesis and the topographic gradient hypothesis of axogenesis.

Answer 17

Revised Chemoaffinity Hypothesis: Neurons find their correct targets using many different chemical cues that act like address labels.

Topographic Gradient Hypothesis: Axons use gradual chemical gradients to form organized maps, connecting matching areas (like retina to brain).

Question 18

Describe the role of neuronal death in synaptic rearrangement.

Answer 18

Neuronal death is normal in brain development. It removes extra or weak neurons, allowing stronger connections to form and reorganize — creating a more efficient and precise neural network.

Question 19

What is the difference between apoptosis and necrosis?

Answer 19

Apoptosis: Programmed, controlled cell death (clean and healthy). Necrosis: Uncontrolled cell death caused by injury (messy and damaging to surrounding tissue).

Question 20

What is perseveration?

Answer 20

Perseveration is the repetition of a behavior or thought even when it’s no longer appropriate. It’s often caused by damage to the prefrontal cortex.

Question 21

The prefrontal cortex is the last part of the nervous system to develop, and it has four functions. What are they?

Answer 21

Planning and decision-making; Working memory (holding and manipulating information); Behavioral inhibition (self-control); Social behavior and personality regulation.