26 Questions
How many neurons are there in the human brain?
86 billions
What is the main component of the Central Nervous System (CNS)?
Brain and spinal cord
Which cells form the nonneural component of the CNS?
Neuroglia (or glia)
What gives a white color to the white matter in the CNS?
Myelin sheaths around the axons
Which part of the brain is covered by gray matter?
Cerebral cortex and cerebellum
What is the function of the meninges in the CNS?
To cover the surface of the brain and spinal cord
What are the supportive cells surrounding CNS neurons called?
Neuroglia (or glia)
What is the main function of white matter in the CNS?
To transmit signals between different parts of the CNS
Which part of the CNS consists primarily of myelinated axons?
White matter
What is the approximate number of synapses in the human brain?
100 trillions
What is the primary function of the spinal cord?
Conduction of information from muscles, joints, and skin
Where is the conus medullaris located?
Tapered inferior end of the spinal cord
What is the function of the dorsal root ganglion?
Receives information from peripheral sensory endings
What is the primary function of the ventral ramus of spinal nerve?
Conducts unconscious information from muscles, joints, and skin
Where is the sympathetic chain ganglion located?
Outside of the spinal cord in the peripheral nervous system
What is the anatomical organization of ascending tracts in the spinal cord?
Contains three neurons: first-order in dorsal root ganglion, second-order ascending to a higher level of CNS, third-order usually in thalamus
Which tract is responsible for conducting unconscious information from muscles, joints, and skin?
Anterior and posterior spinocerebellar tracts
Where does the second-order neuron make synapse with the third-order neuron in ascending tracts?
At a higher level of the CNS
What is the function of the spinotectal tract?
Conducts painful and thermal sensations for spinovisual reflexes
What is the primary function of posterior white columns?
Conduction of discriminative touch, vibratory sense, conscious muscle joint sensations.
Where does the second-order neuron decussate in the ascending pathway?
In the spinal cord
What is the primary function of the third-order neuron in the ascending pathway?
To pass to a sensory region of the cerebral cortex
Where is the cell body of the first-order neuron in the ascending pathway located?
In the dorsal root ganglion
What is the fate of the peripheral process of the first-order neuron in the ascending pathway?
It connects with a sensory receptor ending
Which region of the CNS does the second-order neuron ascend to in the ascending pathway?
Thalamus
What is the main function of the dorsal root ganglion in the ascending pathway?
To connect with a sensory receptor ending
Test your knowledge about the organization and cells of the central nervous system (CNS), including the number of neurons and synapses in the human brain. Learn about the anatomical details of CNS and compare it with other species' nervous systems.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
