39 Questions
What is the function of the axon hillock?
To trigger the initiation of action potentials
Which motor protein is responsible for anterograde transport in axons?
Kinesin
What type of axonal transport is carried out by dynein?
Retrograde transport (+ → -)
What is the main function of neurofilaments in axons?
Structural support
Why do axons generally branch less profusely than dendrites?
For faster signal propagation
What is the main difference between axons and dendrites in terms of length?
Axons are longer than dendrites
What is the term used to refer to the plasma membrane of an axon?
Axolemma
What are the small dilations at the end of axonal branches called?
Terminal boutons
Which layer of the meninges is usually fused but separates to form blood-filled dural venous sinuses in specific areas around the brain?
Meningeal layer
What is the anatomical feature that separates the dura mater from the periosteum of the vertebrae?
Epidural space
What role does the subarachnoid space play in protecting the central nervous system?
It cushions and protects from minor trauma
Which layer of the meninges is described as 'avascular' due to its lack of nutritive capillaries?
Arachnoid
Where does the subarachnoid space communicate with in the brain?
Ventricles
Which part of the meninges has fewer trabeculae in the spinal cord, leading to easier differentiation from the pia mater in that area?
Arachnoid
What is the connective tissue component of the arachnoid continuous with below it?
Pia mater
What type of connective tissue surrounds the trabeculae within the arachnoid?
Collagen and fibroblasts
What is the main function of the BBB?
Prevent microorganisms and harmful substances from entering the brain
Which structure in the brain does NOT have the blood-brain barrier?
Choroid plexus
Which component is responsible for having tight junctions in the BBB?
Capillary endothelial cells
What type of substances pass through the BBB via diffusion?
Lipid-soluble substances
Which structure around the brain ventricles allows certain molecules to affect brain function?
Area postrema
What type of edema can be caused by breaking endothelial cell tight junctions?
Vasogenic edema
Which ions have specific transport mechanisms across the BBB?
$Na^{+}$ and $Cl^{-}$
What role do pericytes play in the BBB?
Forming tight junctions with endothelial cells
What effect do hyperosmolar solutions (e.g., mannitol) have on the blood-brain barrier?
Disrupt the blood-brain barrier
Where is the choroid plexus mainly found in the brain?
Third and fourth ventricles
What happens if there is a decrease in cerebrospinal fluid (CSF) absorption during fetal development?
Hydrocephalus
What is the main function of the choroid plexus in relation to water?
Release water into blood
What is the composition of cerebrospinal fluid (CSF) in terms of ions?
Contains Na+, K+, and Cl- ions
What is the role of CSF in the central nervous system (CNS)?
Cushions against mechanical shocks
Which type of cells are abundant in cerebrospinal fluid (CSF)?
Lymphocytes
Where can CSF be found in the human nervous system?
Ventricles, spinal cord canal, subarachnoid spaces, and perivascular spaces
What type of collagen is found in the external lamina surrounding each Schwann cell?
Type IV collagen
What is the name of the structures that contain Schwann cell cytoplasm and allow for renewal of membrane components in the myelin sheath?
Schmidt-Lanterman clefts
What is the role of the contact between interdigitating processes of Schwann cells and the axolemma at the nodal gap?
Prevents movement of materials in and out of the periaxonal space
Which stain color is used to highlight collagen in the endoneurium surrounding Schwann cells?
Blue
What fills the spaces called Schmidt-Lanterman or myelin clefts within the myelin sheath?
Myelin components and Schwann cell cytoplasm
What is depicted in the lower diagram that shows ultrastructure?
Node of Ranvier or nodal gap
What barrier function does the basal lamina around Schwann cells provide over the nodal gap?
Acts as a barrier to material movement
Explore the structure and function of a neuron's axon, including the axon hillock, synaptic endings, and cytoskeleton components. Learn about axonal transport mechanisms facilitated by motor proteins like kinesin and dynein.
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