Neuroanatomy

What was the debate in the early 1900s regarding the cells of the nervous system?

Golgi believed in a nerve net, while Cajal believed in discrete cells.

What is the neuron hypothesis?

Neurons are the units of brain function.

What did Cajal use the Golgi stain for?

To show that the nervous system is made up of discrete cells.

What does the neuron doctrine state?

The brain is composed of independent cells and information is transmitted from cell to cell across synapses.

What advancements in histology have enabled selective staining of parts of neurons and glia?

Nissl stains, Golgi stains, fluorescent molecule injections, and immunohistochemistry (IHC).

What do Nissl stains outline?

All cell bodies because the dyes are attracted to RNA, which encircles the nucleus.

What do Golgi stains reveal?

Details of the whole cell, but only stain a small proportion of neurons.

What is the purpose of fluorescent molecule injections?

To visualize individual cells in the brain.

What does immunohistochemistry (IHC) detect?

Proteins in tissue.

How can interconnections between neurons be traced?

Using tract tracers that are taken up by neurons and transported through their axons.

What does anterograde labeling reveal?

The axonal targets of cell bodies in a particular region.

What does retrograde labeling reveal?

The cell bodies of axons terminating in a region.

What can some tract tracers do?

Work trans-synaptically.

What is Brainbow?

A technique that allows visualization of individual cells and their connections.

What is the dentate gyrus?

Brain region involved in the formation of new memories and spatial navigation. Located in the hippocampus. Contains granule cells and receives input from the entorhinal cortex.

What is the brainstem?

Part of the central nervous system located at the base of the brain. It connects the brain to the spinal cord and controls essential functions like breathing, heart rate, and blood pressure.

What is the hippocampus?

Part of the brain responsible for memory formation and retrieval. Located in the temporal lobe. Plays a role in learning, spatial navigation, and emotional regulation.

What are Purkinje cells?

Specialized neurons found in the cerebellum that play a crucial role in coordinating and regulating motor movements. They receive input from various sources and transmit signals to other parts of the brain and spinal cord, allowing for smooth and coordinated muscle contractions.

What are neurons?

Flashcard: Neurons

Specialized cells that transmit electrical signals in the nervous system, responsible for processing and transmitting information.

What do glial cells do?

Provide support and contribute to information processing in neurons.

What are the four zones of a neuron?

Input zone, integration zone, conduction zone, output zone.

What is the input zone of a neuron?

Receives information from other cells through dendrites.

What is the integration zone of a neuron?

Cell body region where inputs are combined and transformed.

What is the conduction zone of a neuron?

Single axon that transmits the electrical impulse away from the cell body.

What is the output zone of a neuron?

Axon terminals that communicate activity to other cells.

How are neurons classified?

By shape, size, or function.

What are multipolar neurons?

Neurons with one axon and many dendrites, most common type.

What are bipolar neurons?

Neurons with one axon and one dendrite.

What are unipolar neurons?

Neurons with a single extension branching in two directions.

What do sensory neurons do?

Bring information to the central nervous system.

What do interneurons do?

Associate sensory and motor activity within the central nervous system.

What do motor neurons do?

Send signals from the brain and spinal cord to muscles.

What is the axon hillock?

A cone-shaped area of the cell body that gives rise to the axon.

What are axon collaterals?

Branches of the axon that allow the neuron to innervate more than one postsynaptic cell.

What receives information across synapses?

The neuronal cell body and dendrites.

What is the function of dendritic spines?

They are where synapses form and are important for learning and neural plasticity.

What are the three components of synapses?

Presynaptic neuron, postsynaptic neuron, and the synapse itself.

What is the presynaptic membrane?

Membrane on the axon terminal of the presynaptic neuron.

What is the synaptic cleft?

Gap that separates the membranes.

What is the postsynaptic membrane?

Membrane on the dendrite or cell body of the postsynaptic neuron.

What are synaptic vesicles?

Small spheres in presynaptic axon terminals that contain a neurotransmitter.

What triggers the release of neurotransmitters?

Electrical activity in the axon.

What are receptors in the postsynaptic membrane?

Specialized proteins that react to a neurotransmitter.

What produces most behaviors?

Groups of hundreds or thousands of neurons.

How do neurons change their shape?

They continuously grow and shrink.

Are most neurons replaced?

No, most neurons are with you for life and are never replaced.

What do neurons grow?

New axon collaterals and dendritic spines.

What does the cell membrane do?

Separates intracellular and extracellular fluid and regulates movement of substances.

What are the components of the cell membrane?

Phospholipids with hydrophilic heads and hydrophobic tails.

What structures allow passage of ions?

Channels, gates, and pumps.

What is a channel?

Opening in a protein embedded in the cell membrane that allows the passage of ions.

What is a gate?

Protein embedded in a cell membrane that allows substances to pass only when open.

What is a pump?

Protein embedded in a cell membrane that actively transports a substance across the membrane.

What are organelles?

Internal structures in a cell that perform specific functions.

What do mitochondria do?

Produce energy.

What does the cell nucleus contain?

Genetic instructions.

What is the function of ribosomes?

Translate genetic instructions into proteins.

What is the function of the nucleus?

Cell's 'executive office', where DNA resides.

What is the function of the endoplasmic reticulum?

Protein structures that act as catalysts for protein synthesis.

What is the function of Golgi bodies?

Package proteins in membranes (vesicles) and give them a 'label' indicating where they are to go.

What is the function of microtubules?

Transport vesicles to where they need to go within the cell or outside of the cell.

What happens to proteins in vesicles in neuroanatomy?

They are transported down the axon, incorporated into the membrane, or remain in the cell to act as enzymes.

What is the function of exocytosis in neurotransmission?

Excretes proteins from the cell.

How many main types of glial cells are there?

Five.

What is the function of ependymal cells?

Make and secrete cerebrospinal fluid (CSF).

What is the function of astrocytes?

Provide structural support for neurons, transport substances between neurons and capillaries, form scar tissue.

What is the function of astrocytes in relation to blood flow?

Detect neural activity and regulate adjacent capillaries to control blood flow.

What is the function of microglia?

Scavenge debris, remove damaged/sick cells, help prune synapses during development.

What is the function of oligodendrocytes and Schwann cells?

Provide myelination for neurons.

What is the function of glial cells?

Insulate cells and myelinate axonal segments

What is the role of oligodendrocytes?

Myelinate multiple axonal segments in the central nervous system

What is the role of Schwann cells?

Myelinate one axonal segment in the peripheral nervous system

Why is myelin integral for rapid neural communication?

It insulates the cell and allows for faster transmission of signals

What is multiple sclerosis?

A condition where the myelin is damaged, leading to impaired neural communication

What are the consequences of paralysis?

Loss of sensation and movement due to nervous system injury

Does repair of the nervous system take place?

In the central nervous system, repair does not take place, while in the peripheral nervous system, microglia and Schwann cells help repair neurons

What is gross neuroanatomy?

The study of the overall structure of the nervous system

What are the terms used to describe direction in neuroanatomy?

Dorsal/Superior, Ventral/Inferior, Rostral/Anterior, Caudal/Posterior, Medial, Lateral

How does the axis change for the brainstem and spinal cord in humans?

The axis changes direction

What are the different planes of neuroanatomical sections?

Horizontal/Axial, Sagittal, Coronal

What does afferent mean in neuroanatomy?

Inputs to a brain structure

What does efferent mean in neuroanatomy?

Projections from a brain structure

What does contralateral mean?

On the opposite side

What does ipsilateral mean?

On the same side