How many pairs of cranial nerves and spinal nerves are there in the human body?
- A.10 cranial and 33 spinal
- B.12 cranial and 31 spinal
- C.12 cranial and 33 spinal
- D.31 cranial and 12 spinal
Correct answer
Explanation
The correct answer is B, 12 cranial and 31 spinal. Twelve pairs of cranial nerves arise from the brain and serve the head and neck, among them the optic nerve of sight, the auditory nerve of hearing and the vagus, the longest cranial nerve, which reaches the heart and the abdomen; thirty-one pairs of spinal nerves arise from the spinal cord, made up of eight cervical, twelve thoracic, five lumbar, five sacral and one coccygeal pair. Option A is wrong on both counts and the figure 33 belongs to the vertebrae of the backbone, not to nerves. Option C is wrong because it mixes the correct number of cranial nerves with the vertebral count. Option D is wrong because it simply exchanges the two numbers, a common trap in matching questions.
Read the full article: Human Body Important Facts for Competitive Exams
Practice Questions
View allWhich is the smallest bone in the human body?
- A.Stapes
- B.Malleus
- C.Incus
- D.Hyoid
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The stapes, shaped like a stirrup, is the innermost of the three ossicles of the middle ear and is the smallest bone in the human body, measuring only a few millimetres; the smallest muscle of the body, the stapedius, is attached to it.
Read the full explanation →How many bones are there in the body of an adult human being?
- A.186
- B.206
- C.256
- D.300
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The adult human skeleton has 206 bones, of which 80 belong to the axial skeleton, that is the skull, vertebral column and chest, and 126 to the appendicular skeleton of the limbs and girdles.
Read the full explanation →Which is the largest gland in the human body?
- A.Thyroid
- B.Pancreas
- C.Liver
- D.Pituitary
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The liver weighs about one and a half kilograms and is both the largest gland and the largest internal organ of the body; it secretes bile, stores glycogen, iron and vitamin A, converts ammonia into urea and detoxifies drugs and poisons.
Read the full explanation →Which structure is called the pacemaker of the human heart?
- A.Atrio-ventricular node
- B.Sino-atrial node
- C.Bundle of His
- D.Purkinje fibres
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The sino-atrial node is a small patch of specialised muscle tissue in the wall of the right atrium near the opening of the superior vena cava, and it generates the impulse that sets the rate of each heartbeat without any outside stimulus, which is why it is called the pacemaker.
Read the full explanation →What is the average life span of a red blood cell in the human body?
- A.About 10 days
- B.About 60 days
- C.About 120 days
- D.About 365 days
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Red blood cells are produced in the red bone marrow, lose their nucleus on maturing and survive roughly four months, after which they are broken down in the spleen, which is accordingly called the graveyard of red blood cells; the iron released from their haemoglobin is used again.
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