Anatomical Introduction to Central Nervous System (CNS)

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How many neurons are there in the human brain?

86 billions (correct)

302

16 billions

100,000

What is the main component of the Central Nervous System (CNS)?

Neurons and synapses

Astrocytes and microglia

Brain and spinal cord (correct)

Meninges and cerebrospinal fluid

Which cells form the nonneural component of the CNS?

Microglia

Neuroglia (or glia) (correct)

Oligodendrocytes

Neurons

What gives a white color to the white matter in the CNS?

Myelin sheaths around the axons Signup and view all the answers

Which part of the brain is covered by gray matter?

Cerebral cortex and cerebellum Signup and view all the answers

What is the function of the meninges in the CNS?

To cover the surface of the brain and spinal cord Signup and view all the answers

What are the supportive cells surrounding CNS neurons called?

Neuroglia (or glia) Signup and view all the answers

What is the main function of white matter in the CNS?

To transmit signals between different parts of the CNS Signup and view all the answers

Which part of the CNS consists primarily of myelinated axons?

White matter Signup and view all the answers

What is the approximate number of synapses in the human brain?

100 trillions Signup and view all the answers

What is the primary function of the spinal cord?

Conduction of information from muscles, joints, and skin Signup and view all the answers

Where is the conus medullaris located?

Tapered inferior end of the spinal cord Signup and view all the answers

What is the function of the dorsal root ganglion?

Receives information from peripheral sensory endings Signup and view all the answers

What is the primary function of the ventral ramus of spinal nerve?

Conducts unconscious information from muscles, joints, and skin Signup and view all the answers

Where is the sympathetic chain ganglion located?

Outside of the spinal cord in the peripheral nervous system Signup and view all the answers

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 Signup and view all the answers

Which tract is responsible for conducting unconscious information from muscles, joints, and skin?

Anterior and posterior spinocerebellar tracts Signup and view all the answers

Where does the second-order neuron make synapse with the third-order neuron in ascending tracts?

At a higher level of the CNS Signup and view all the answers

What is the function of the spinotectal tract?

Conducts painful and thermal sensations for spinovisual reflexes Signup and view all the answers

What is the primary function of posterior white columns?

Conduction of discriminative touch, vibratory sense, conscious muscle joint sensations. Signup and view all the answers

Where does the second-order neuron decussate in the ascending pathway?

In the spinal cord Signup and view all the answers

What is the primary function of the third-order neuron in the ascending pathway?

To pass to a sensory region of the cerebral cortex Signup and view all the answers

Where is the cell body of the first-order neuron in the ascending pathway located?

In the dorsal root ganglion Signup and view all the answers

What is the fate of the peripheral process of the first-order neuron in the ascending pathway?

It connects with a sensory receptor ending Signup and view all the answers

Which region of the CNS does the second-order neuron ascend to in the ascending pathway?

Thalamus Signup and view all the answers

What is the main function of the dorsal root ganglion in the ascending pathway?

To connect with a sensory receptor ending Signup and view all the answers