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What is the composition of gray matter in the CNS?
Gray matter consists primarily of neuronal cell bodies, dendrites, and neuroglia (supporting cells). It is found in the cortex of the brain and in nuclei deep within the brain and spinal cord.
What is the difference between a nucleus and a ganglion?
How do the meninges relate to the CNS (brain and spinal cord)?
The meninges surround and protect the brain and spinal cord, providing a cushioning layer and serving as a barrier to pathogens. The pia mater is closest to the CNS, while the dura mater is the outermost layer.
Which of these spaces contains cerebrospinal fluid (CSF)?
The subarachnoid space contains CSF, which cushions the brain and spinal cord and facilitates nutrient and waste exchange.
Why is the blood-brain barrier important?
The BBB prevents toxins, pathogens, and certain drugs from entering the brain, while allowing essential substances like glucose and oxygen to pass through.
What is the composition of white matter in the CNS?
White matter is composed mainly of myelinated axons, glial cells (such as oligodendrocytes), and blood vessels. It is found in the deeper regions of the brain and the spinal cord.
Where are nuclei and ganglia located?
What is the difference between the dura mater surrounding the brain and the spinal cord?
Where is cerebrospinal fluid (CSF) produced?
CSF is produced in the choroid plexuses of the ventricles in the brain.
What are the five lobes of the cerebral hemispheres?
What are the motor and sensory neuronal elements in a typical nerve?
Motor neurons transmit signals from the CNS to muscles, while sensory neurons carry signals from sensory receptors to the CNS.
What is the difference between a tract and a nerve?
What are the dural venous sinuses and where are they located?
The dural venous sinuses are large venous channels located between the meningeal and periosteal layers of the dura mater. Key sinuses include the superior sagittal sinus, transverse sinuses, and sigmoid sinuses.
Describe the flow of CSF in the brain and spinal cord.
CSF flows from the lateral ventricles → third ventricle → cerebral aqueduct → fourth ventricle → subarachnoid space around the brain and spinal cord.
What are the cerebral hemispheres?
The cerebral hemispheres are the two halves of the cerebrum, each controlling the opposite side of the body and responsible for different functions.
What neuroglial elements are found in a typical nerve?
Neuroglial elements include Schwann cells (for myelination in peripheral nerves), satellite cells (for support and nutrient supply to neurons), and axons.
Where are tracts and nerves located?
What role do the dural venous sinuses play in blood drainage from the brain?
They collect deoxygenated blood from the brain and CSF, eventually draining into the internal jugular veins, returning the blood to the heart.
How is CSF reabsorbed into the bloodstream?
CSF is reabsorbed into the bloodstream through the arachnoid villi (granulations) that project into the dural venous sinuses, particularly the superior sagittal sinus.
What is the longitudinal fissure?
The longitudinal fissure is a deep groove that divides the brain into the right and left cerebral hemispheres.
What are the connective tissue wrappings of a typical nerve?
- Endoneurium: Surrounds individual nerve fibers.
- Perineurium: Surrounds bundles of nerve fibers (fascicles).
- Epineurium: Surrounds the entire nerve, providing protection and structure.
What are the three layers of the meninges?
The meninges consist of the dura mater, arachnoid mater, and pia mater.
What are the epidural, subdural, and subarachnoid spaces?
What is the blood-brain barrier (BBB)?
The BBB is a selective barrier that protects the brain from harmful substances and regulates the passage of nutrients, gases, and waste products between the blood and the brain tissue.
What is the lateral sulcus (also called Sylvian fissure)?
The lateral sulcus is a deep groove that separates the temporal lobe from the frontal and parietal lobes.