Q1. The “Nissl substance” represents which organelle of neuron?
A. Golgi complex
C. Rough endoplasmic reticulum
Ans: The cytoplasm of a neuron shows the presence of a granular material that stains intensely with basic dyes called Nissl substance (also called Nissl bodies or granules) . These bodies are rough endoplasmic reticulum
Q2. Which of the following provides myelin sheath to the axons of the CNS?
Ans: Oligodendrocytes form myelin sheath in CNS. Schwann cells form myelin sheath in PNS
Q3. The perivascular foot of the “blood–brain barrier” is an extension from the:
Ans: Astrocytes form the perivascular feet around a capillary. Astrocytes act as insulators, nourish the neurons, help form blood-brain barrier.
Q4. Sensation of pain is detected by:A. Mechanoreceptor
Q5. The cerebral aqueduct is developed from the cavity of:A. Rhombencephalon
Ans: The cavity of each telencephalic vesicle becomes the lateral ventricle. The cavity of iencephalon (along with the central part of the telencephalon) becomes the third ventricle. The cavity of the mesencephalon remains narrow, and forms the cerebral aqueduct (aqueduct of Sylvius). The cavity of the rhombencephalon forms the fourth ventricle. Its continuation in the spinal cord is the
Q6. The failure of closure of the cranial end of neural tube gives rise to:A. Anencephaly
Ans: The neural tube remains open in the region of the brain because of nonclosure of the anterior neuropore. This results in anencephaly. Brain tissue, which is exposed, degenerates
Q7. By which week of intrauterine life does the neural tube close?
Ans: At 4 weeks the neural tube is normally completely closed (Ref: https://embryology.med.unsw.edu.au/embryology/index.php/Timeline_human_development#Neural)
Q8. The cervical flexure of the neural tube occurs:A. Between the forebrain and midbrain
B. In the midbrain
C. Between hindbrain and spinal cord
D. In the hindbrain
Ans: The cervical flexure lies at the junction of the rhombencephalon and the spinal cord
Ans: Rabies virus, from the site of bite, travels along nerves by reverse axoplasmic flow.
Q10:Polio virus is also transported from the gastrointestinal tract through :
Ans: Polio virus is also transported from the gastrointestinal tract through reverse axoplasmic flow.
Ans: Tetanus bacteria travels from the site of infection to the brain along the endoneurium of nerve fibres