Biology

Nervous System and Neurons

1,224 Questions

The nervous system and neurons section covers the structural and functional aspects of the human nervous system. Topics include nerve fibers, the myelin sheath, and sympathetic nervous system functions. This material is crucial for general science preparation in various competitive exams.

Neuron structureMyelin sheath productionSympathetic nervous systemCranial and spinal nervesParasympathetic functions

Nervous System and Neurons Questions

Multiple choice general knowledge science & technology

In nerve axon (the wire-like part), signals are transmitted by a mechanism involving ion of one element being forced out and ion of another element forced in across cell membrane and vice versa. Thus electric waves are created due to differing electro-polarity of the elements. Natural Selection of Evolution appears to have been based on maximum sensitivity for least calory, i.e. maximum polarity with lightest weight of atoms, & easy availability of the elements as nutrition. Again these 2 ions raise the base potential around which nervous signals operate too high to be affected by interference from other normal electrochemical reactions in the cell. What are the 2 elements?

  1. Hydrogen & Chlorine

  2. Calcium & Magnesium

  3. Phosphorus & Sodium

  4. Sodium & Potassium
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Nerve impulses rely on the sodium-potassium pump, where sodium ions (Na+) are pumped out and potassium ions (K+) are pumped in. This creates the electrochemical gradient responsible for action potentials. These elements are abundant in nature and have optimal charge-to-weight ratio for rapid signaling.

Multiple choice general knowledge

Longest nerve in human body

  1. Optic

  2. Cranial

  3. Vagus

  4. Sciatic
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The sciatic nerve is the longest nerve in the human body, running from the lower back down through the leg to the foot. It's about 1 meter long in adults. Cranial and optic nerves are much shorter. The vagus nerve is long but doesn't extend as far as the sciatic.

Multiple choice general knowledge

how many pairs of Cranial nerves are in human body

  1. 10 pairs

  2. 8 pairs

  3. 12 pairs

  4. 6 pairs
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Humans have 12 pairs of cranial nerves that emerge from the brainstem, numbered I through XII. These control vital functions including smell, vision, eye movement, and facial expressions. The 12-pair count is a fundamental anatomical fact across all standard medical textbooks.

Multiple choice general knowledge science & technology

What is the part of the nervous systems that deals with survival functions, like breathing.

  1. Central nervous system

  2. Peripheral nervous system

  3. Somatic nervous system

  4. Autonomic nervous system
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The autonomic nervous system controls involuntary survival functions like breathing, heart rate, and digestion. The central nervous system consists of brain and spinal cord, peripheral connects CNS to the body, and somatic controls voluntary muscle movements.

Multiple choice general knowledge

deals with problems of brain and nerves

  1. Nephrologist

  2. Optometrist

  3. Neruologist

  4. Endocrinologist
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A neurologist specializes in treating disorders of the brain and nervous system. Note option C has a typo ('Neruologist' should be 'Neurologist'), but it's clearly the intended answer. Other options treat kidneys, eyes, or hormones.

Multiple choice general knowledge science & technology

The human brain is made up of approximately....

  1. 400 billion neurons

  2. 300 billion neurons

  3. 200 billion neurons

  4. 100 billion neurons
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The human brain contains approximately 100 billion neurons, though estimates range from 86-100 billion. This massive network of neurons forms the basis for all brain functions, from basic survival reflexes to complex cognitive processes.

Multiple choice general knowledge science & technology

Brain has over 100,000,000,000 nerver cells each with up to 150,000 connections. Each cell is connected to 25,000 others.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The human brain contains approximately 100 billion neurons. While each neuron can form thousands of connections (synapses), the exact number varies by region and individual. The statement captures the immense complexity of neural networks in the brain.

Multiple choice

The nature of a nerve impulse is primarily a/an __________ event, whereas, the nature of the communication between neurons is primarily a/an __________ event.

  1. chemical, electrical

  2. acetylcholine, catecholamine

  3. dendrite, axon

  4. electrical, chemical
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Within a neuron, the action potential (nerve impulse) is an electrical event caused by ion movement. Communication BETWEEN neurons at synapses is primarily chemical (neurotransmitters). Acetylcholine and catecholamine are specific neurotransmitters, not event types. Dendrites and axons are neuron structures.

Multiple choice

An action potential actually occurs because

  1. the interior of the nerve cell becomes positive

  2. the interior of the nerve cell becomes negative

  3. potassium ions enter the nerve cell

  4. sodium ions leave the nerve cell
Reveal answer Fill a bubble to check yourself
D Correct answer
Multiple choice

Neural circuits of many sensory systems

  1. respond to specific stimulus patterns

  2. respond to the whole visual field

  3. respond primarily to stationary objects

  4. develop only after birth
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Neural circuits in sensory systems are highly specialized and respond selectively to specific stimulus patterns through feature detection. For example, visual cortex neurons respond to specific orientations, edges, or movements. They don't respond to the entire visual field, aren't limited to stationary objects, and many sensory circuits are present at birth (innate).

Multiple choice

The pain-killing effects of acupuncture may be related to

  1. sensory adaptation

  2. stabilization of physiological nystagmus

  3. the triggering of perceptual defense systems

  4. release of endorphins
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Acupuncture's pain-relieving effects are mediated by the release of endorphins - the body's natural painkillers. Research shows that naloxone (an endorphin antagonist) can block acupuncture's analgesic effects, supporting this mechanism. Sensory adaptation (A) refers to diminished sensitivity to constant stimuli. Physiological nystagmus (B) is involuntary eye movement. Perceptual defense (C) involves delayed recognition of threatening stimuli.