Smell is the only sense whose pathway reaches the cerebral cortex without first synapsing in the thalamus.
Correct Answer
True
True. Olfactory bulb axons project directly to the olfactory cortex of the temporal lobe and to limbic areas. Every other sense is relayed through a thalamic nucleus before reaching its cortical area.
Category: Sensory Pathways
Question 2
Sour taste results from potassium ions entering gustatory receptor cells.
Correct Answer
False
False. Sour taste is produced by hydrogen ions from acids entering gustatory cells and depolarizing them. The more acidic the food, the stronger the response.
Category: Special Senses
Question 3
Sweet, bitter and umami tastes are detected through G protein-coupled receptors.
Correct Answer
True
True. These three tastes depend on receptor proteins that activate G proteins and second messenger pathways. Salty and sour tastes instead rely on ions entering the cell directly.
Category: Special Senses
Question 4
The auditory (Eustachian) tube equalizes air pressure on the two sides of the tympanic membrane.
Correct Answer
True
True. The auditory tube connects the middle ear to the pharynx, letting air in or out so pressure in the middle ear matches outside pressure. This lets the eardrum vibrate freely.
Category: Special Senses
Question 5
Cochlear hair cells depolarize when their stereocilia bend toward the shortest stereocilium.
Correct Answer
False
False. Hair cells depolarize when their stereocilia bend toward the tallest stereocilium, which opens mechanically gated ion channels. Bending toward the shortest closes those channels.
Category: Special Senses
Question 6
The optic disc creates a blind spot because it contains no photoreceptors.
Correct Answer
True
True. The optic disc is where ganglion cell axons leave the eye and blood vessels enter and leave it. With no rods or cones there, light falling on it cannot be detected.
Category: Vision
Question 7
Rods provide color vision, while cones function mainly in dim light.
Correct Answer
False
False. Cones provide color vision and sharp vision in bright light, while rods are very sensitive and function in dim light. Rods give only grayscale vision.
Category: Vision
Question 8
Vitreous humor fills the anterior cavity of the eye.
Correct Answer
False
False. The anterior cavity, in front of the lens, is filled with watery aqueous humor. Vitreous humor is the jelly-like substance that fills the larger posterior cavity behind the lens.
Category: Vision
Question 9
The lateral rectus muscle of the eye is innervated by the trochlear nerve.
Correct Answer
False
False. The lateral rectus is innervated by the abducens nerve, cranial nerve VI, which abducts the eye. The trochlear nerve supplies the superior oblique.
Category: Vision
Question 10
At the optic chiasm, axons from the nasal (medial) half of each retina cross to the opposite side of the brain.
Correct Answer
True
True. Nasal retinal fibers cross at the optic chiasm while temporal fibers stay on the same side. As a result, each hemisphere receives information about the opposite visual field.
Category: Sensory Pathways
Question 11
The dorsal column system mainly carries pain and temperature information to the brain.
Correct Answer
False
False. The dorsal column system carries fine touch, vibration and proprioception. Pain and temperature travel in the spinothalamic tract.
Category: Sensory Pathways
Question 12
Both the dorsal column system and the spinothalamic tract use a chain of three neurons to carry information from the receptor to the cortex.
Correct Answer
True
True. In each pathway a first-order neuron enters the spinal cord, a second-order neuron crosses to the opposite side, and a third-order neuron in the thalamus projects to the somatosensory cortex.
Category: Sensory Pathways
Question 13
The primary visual cortex is located in the temporal lobe.
Correct Answer
False
False. The primary visual cortex is in the occipital lobe, at the back of the cerebrum. The temporal lobe contains the auditory cortex.
Category: Cortical Processing
Question 14
In the primary somatosensory cortex, the fingers and lips are represented by a larger area than the trunk.
Correct Answer
True
True. Cortical area reflects receptor density and sensitivity, not body size. The densely innervated fingers, lips and face take up far more of the sensory map than the back or trunk.
Category: Cortical Processing
Question 15
The dorsal visual stream, which projects into the parietal lobe, helps locate objects in space and guide movement toward them.
Correct Answer
True
True. The dorsal stream processes where objects are and connects to motor areas of the frontal lobe. The ventral stream, running into the temporal lobe, identifies what objects are.
Category: Cortical Processing
Question 16
Broca's area is mainly responsible for the comprehension of spoken language.
Correct Answer
False
False. Broca's area, in the frontal lobe, controls the movements used to produce speech. People with damage there can often understand speech but struggle to speak.
Category: Motor Control
Question 17
Because most of the corticospinal tract crosses over, the left primary motor cortex controls skeletal muscles on the right side of the body.
Correct Answer
True
True. Most corticospinal fibers decussate at the medullary pyramids, so each hemisphere controls the opposite side of the body. This is why a stroke in one hemisphere weakens the opposite limbs.
Category: Motor Control
Question 18
The anterior corticospinal tract mainly controls the muscles of the arms and legs.
Correct Answer
False
False. The anterior corticospinal tract controls axial muscles of the trunk. The lateral corticospinal tract controls the appendicular muscles of the limbs.
Category: Motor Control
Question 19
In the stretch reflex, the stretched muscle contracts while motor neurons to its antagonist are inhibited.
Correct Answer
True
True. A muscle spindle activated by stretch excites the motor neurons of the same muscle, and a collateral acts through an inhibitory interneuron to relax the antagonist. This keeps muscle length steady.
Category: Reflexes
Question 20
In a withdrawal reflex, the antagonist muscle relaxes because an inhibitory neurotransmitter is released onto it at the neuromuscular junction.
Correct Answer
False
False. The neuromuscular junction is only excitatory. The antagonist relaxes because an inhibitory interneuron in the spinal cord stops its motor neuron from firing.
Category: Reflexes