Question
_____is the white fatty layer covering the axon that increases the speed of conduction of nerve impulses.
The correct answer is
Myelin sheath
Identifying the Axon's Fatty Layer
The question asks to identify the white, fatty layer that covers an axon and speeds up nerve impulse transmission.
Understanding the Myelin Sheath Function
The structure described is the myelin sheath. This is a fatty, insulating layer that surrounds the axons of many neurons.
- Insulation: The myelin sheath acts like insulation on an electrical wire.
- Saltatory Conduction: It allows nerve impulses to jump between gaps in the sheath (Nodes of Ranvier), significantly increasing the speed of conduction compared to unmyelinated axons.
Evaluating the Options
- Cell membrane: This is the basic outer boundary of any cell, including neurons, but it doesn't provide the specific insulation or speed enhancement described.
- Bulb: This typically refers to the synaptic bulb, the terminal end of an axon where neurotransmitters are released.
- Myelin sheath: This perfectly matches the description of a white, fatty layer that insulates the axon and speeds up nerve impulse conduction.
- Cleft: This refers to the synaptic cleft, the small gap between two neurons across which nerve impulses are transmitted.
Therefore, the correct identification is the myelin sheath.
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Important Questions from Biological Basis of Behaviour Neurons Synapses
Consider the following two statements and choose the correct option.
S1: Patients with Broca's aphasia have trouble producing speech.
S2: Patients with Wernicke's aphasia have trouble understanding what others say.- ________ in both lobes of the brain are responsible for coordination and interpretation of information as well as higher mental processing.
- Match the concerned human nervous system with their associated functions.
P. Sympathetic (i) Carrying messages from Central Nervous
System to muscles and glandsQ. Parasympathetic (ii) Carrying messages from senses to Central
Nervous SystemR. Afferent (iii) Maintaining body functions under normal
conditionsS. Efferent (iv) Fight-or-flight system If Central Nervous System = Brain + Spinal Cord, then Peripheral Nervous System = ?
- Match the neurotransmitters with their functions
P. Acetylcholine (i) Movement and pleasure sensation Q. Dopamine (ii) Sleep, anxiety, and appetite R. Serotonin (iii) Attention and memory S. Norepinephrine (iv) Arousal and mood
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