MLT GlobeAnatomy: Nervous system
56 Anatomy MCQs on Nervous system with answers and explanations.
A CSF sample is sent to the lab. Where in the brain was this fluid mainly produced?
Ependymal cells of the choroid plexuses secrete most CSF. Arachnoid granulations reabsorb CSF into the venous sinuses.
Which cells form myelin around axons in peripheral nerves?
Schwann cells myelinate peripheral axons. Oligodendrocytes do this in the CNS; satellite cells surround ganglion cell bodies.
A patient's protruded tongue deviates to one side. Which cranial nerve supplying tongue muscles is likely affected?
The hypoglossal nerve supplies almost all tongue muscles; a lesion makes the tongue deviate toward the weak side. V3, VII and IX carry tongue sensation or taste.
Lower motor neurone cell bodies supplying limb muscles lie in the:
Anterior horn cells are lower motor neurones whose axons leave by ventral roots. Posterior horns receive sensory input; upper motor neurones start in the cortex.
The autonomic nervous system mainly controls:
Autonomic nerves regulate involuntary visceral targets: smooth muscle, heart and glands. Skeletal muscle is under somatic motor control.
Which is the thickest and longest nerve in the human body?
The sciatic nerve (L4–S3) is the largest nerve, running down the back of the thigh before dividing into tibial and common fibular nerves.
Weakness of the muscles of facial expression on one side (e.g., inability to close the eye) points to damage of which nerve?
The facial nerve supplies the muscles of facial expression, as in Bell's palsy. The trigeminal nerve gives facial sensation and supplies masticatory muscles.
Which structure forms part of the brainstem?
The brainstem consists of the midbrain, pons and medulla oblongata. The thalamus is diencephalon; the cortex and hippocampus belong to the cerebrum.
The trigeminal nerve divides into three branches. Which nerve is NOT one of them?
The trigeminal (V) branches are ophthalmic, maxillary and mandibular. The trochlear is cranial nerve IV supplying the superior oblique.
The vagus nerve is which cranial nerve?
The vagus (X) supplies parasympathetic fibres to thoracic and abdominal viscera. III is oculomotor, V trigeminal, XII hypoglossal.
Receptors in muscles, tendons and joints that signal limb position and movement are:
Proprioceptors (muscle spindles, Golgi tendon organs, joint receptors) report position and movement. Exteroceptors respond to external stimuli.
The ventricles of the brain are filled with which fluid, often sampled in suspected meningitis?
CSF fills the ventricles and subarachnoid space; lab analysis of cells, protein, glucose and microbes aids diagnosis of CNS infection.
A patient loses sight after a stroke although both eyes are normal. Damage to which brain region best explains this?
The primary visual cortex lies in the occipital lobe around the calcarine sulcus. The hypothalamus and medulla control autonomic functions, not conscious vision.
A lesion in the left motor cortex causes weakness of the right limbs. Which term describes the side of the weakness relative to the lesion?
Contralateral means on the opposite side of the body. Ipsilateral means the same side as the reference point.
Damage to the hypothalamus would most directly disturb regulation of which function?
The hypothalamus contains the thermoregulatory centre and also controls hunger, thirst and pituitary output. Colour vision is cortical and retinal.
Which glial cell type is found only in the peripheral, not the central, nervous system?
Schwann cells myelinate peripheral axons. Astrocytes, microglia, oligodendrocytes and ependymal cells are CNS glia.
Which structures make up the peripheral nervous system?
The PNS comprises all nerves and ganglia outside the brain and spinal cord, which together form the CNS.
In multiple sclerosis, CNS myelin is lost. Which cells produce this myelin?
Oligodendrocytes myelinate CNS axons, each serving several axons. Schwann cells form myelin only in the peripheral nervous system.
Which cranial nerve emerges from the medulla oblongata?
CN IX, X, XII (and cranial XI) arise from the medulla. The oculomotor emerges from the midbrain; CN I and II are extensions of the forebrain.
Functionally, every spinal nerve is classified as:
Each spinal nerve forms from a dorsal (sensory) and ventral (motor) root, so it carries both sensory and motor fibres.