Basic Neuroanatomy Flashcards
The cytoskeleton is a network of three types of filamentous proteins - what are they called?
Microfilaments, neurofilaments/intermediate filaments and microtubules
What is the basic functional unit of the nervous system?
Neuron
True or False: The cerebellum is responsible for voluntary motor control.
True
Fill in the blank: The _______ is the part of the brain that regulates homeostasis.
Hypothalamus
What structure connects the left and right hemispheres of the brain?
Corpus callosum
Which part of the neuron receives signals from other neurons?
Dendrites
What are the two main types of cells in the nervous system?
Neurons and glial cells
True or False: The spinal cord is part of the peripheral nervous system.
False
Which lobe of the brain is primarily responsible for processing visual information?
Occipital lobe
What is the role of myelin in the nervous system?
To insulate axons and increase the speed of signal transmission
Fill in the blank: The _______ is the outer layer of the brain.
Cerebral cortex
What type of neurotransmitter is primarily involved in muscle contraction?
Acetylcholine
Which structure in the brain is involved in memory formation?
Hippocampus
True or False: The amygdala is involved in emotional processing.
True
What is the function of the thalamus?
To relay sensory information to the appropriate areas of the brain
What are the three main parts of the brainstem?
Midbrain, pons, and medulla oblongata
Fill in the blank: The _______ is responsible for the ‘fight or flight’ response.
Sympathetic nervous system
Which type of glial cell is responsible for forming the blood-brain barrier?
Astrocytes
What is the primary function of the frontal lobe?
Higher cognitive functions such as reasoning, planning, and problem-solving
True or False: The brain is divided into four main lobes.
True
What is the role of the medulla oblongata?
To regulate vital functions such as heart rate and breathing
Fill in the blank: The _______ nervous system is responsible for involuntary body functions.
Autonomic
What is the primary role of the parietal lobe?
Processing sensory information related to touch and body position
Which part of the neuron transmits signals away from the cell body?
Axon
True or False: The limbic system is involved in the regulation of emotions.
True
What is the main function of the occipital lobe?
Visual processing
Fill in the blank: _______ are the cells that support and protect neurons.
Glial cells
Which part of the cytoskeleton is two polymers of globular actin protein intertwined, with a diameter of 3nm-7nm? Where is it found and what are its three main functions?
Microfilaments. Prevalent at the edges of the cell, just inside the membraneat the cell cortex. It provides the basic strength and shape of the cell, positions vesicles and receptors in the synapses and allows for dendritic movements/remodelling as G-actin can be added and removed to change shape and create new synapses.
Why are vesicles needed to transport proteins to the axon terminals?
Ribosomes which synthesise proteins are only found in cell bodies, not in axons or nerve terminals.
Name this part of the cytoskeleton:
Diameter 7nm-11nm, protein composition dependent on cell type. Two tight, spiral coils (protofilaments) twist together into a protofibril. Three protofibrils twist together.
85% of total protein in a neurone! The largest population is found in motor neurones.
Provide support and stability to axons. Organise a cell’s internal structure and keep organelles in place.
Neurofilaments / intermediate filaments.
Which is the strongest filament in the cytoskeleton? Why?
Neurofilaments / intermediate filaments because of their structure - two spiral coils of protofilaments form a protofibril, three protofibrils twist into a neurofilament.
Name this structure found in the cytoskeleton:
Diameter of 20nm-28nm. A polymer of tubulin molecules - alpha-tubulin and beta-tubulin form a dimer, which polymerises into a tubular formation.
Arranged longitudinally along axons and dendrites, their shape can be altered by polymerisation and depolymerisation at either end.
They have roles in cell movement and axonal transport.
Microtubules.
Which cytoskeleton structure can be found arranged longitudunally along axons and dendrites?
Microtubules.
In which direction does ORTHOGRADE cell transport go?
From the cell body to the axonal terminals.
In which direction does RETROGRADE cell transport go?
From the axonal terminals to the cell body.
What is the approximate speed of ‘slow’ axonal transport, in mm/day.
1mm/day.
What is the approximate speed of ‘fast’ axonal transport, in mm/day?
100mm/day - 400mm/day.
Name the specialised protein involved in orthograde transport.
Kinesin.
Which specialised protein has the following two parts:
- an amino terminal, which is the motor domain. ATPase activity uses ATP to ‘walk’ along microtubules with its ‘feet’.
- the divergent tail directs the protein to a specific organelle, vesicle etc. that the protein needs to transport.
Kinesin.
Which specialised protein uses ATP to ‘walk’ along microtubules in orthograde transport.
Kinesin.
Which specialised protein is responsible for retrograde transport?
Dyenin.
How do kinesin and dyenin obtain the energy they need to carry molecules along microtubules?
ATP hydrolysis.
Which neuroglia are found in the CNS?
HINT: there are four.
Astrocytes.
Oligodendrocytes.
Microglia.
Ependymal cells.
Which neuroglia are found in the PNS?
HINT: there are two.
Schwann cells.
Satellite cells.
Name the neuroglia:
‘Functions include guiding neurones during development, structural support for neurones and capillaries, nourishment of neurones, as a buffer for extracellular ions, the uptake and storage of certain neurotransmitters, participation in glia-neurone and glia-glia communication, chemical signalling, formation of the blood-brain barrier’.
Astrocytes.
What are some of the functions of astrocytes?
Guiding neurones during development, structural support for neurones and capillaries, nourishment of neurones, as a buffer for extracellular ions, the uptake and storage of certain neurotransmitters, participation in glia-neurone and glia-glia communication, chemical signalling, formation of the blood-brain barrier.
Name the neuroglia:
‘The main function is as specialised macrophages. They play an important role in the CNS’ immune response to infection and tissue damage’.
Microglia.
What is the main function of microglia?
In the CNS’ immune system, they act as specialised macrophages.
Name the neuroglia:
‘Living in the ventricles and central canal of the spinal cord, many are ciliated to produce and facilitate the flow of cerebrospinal fluid’.
Ependymal cells.
Which neuroglia have finger-like processes in order to facilitate the flow of cerebrospinal fluid?
Cilia in ependymal cells.
What do ependymal cells do? Why do they have cilia?
They facilitate the flow of cerebrospinal fluid, the cilia are finger-like processes which help them to do this.
Name the neuroglia:
‘functions include myelination of axons in the CNS in 1mm-2mm segments, making action potentials move up to 100x faster. These neuroglia can myelinate a whole axon or several axons at once’.
Oligodendrocytes.
What is the main function of oligodendrocytes in the CNS?
Myelination of axons.
Which cells mylinate axons in the PNS?
Schwann cells.
How do schwann cells differ from oligodendrocytes?
Schwann cells can only myelinate one segment of axon each, whereas oligodendrocytes can myelinate a whole axon or several axons at once.
What are the Nodes of Ranvier?
The gaps between the myelinated sections of an axon.
What causes multiple sclerosis?
Los of myelination in the CNS?
Name some of the symptoms of multiple sclerosis.
Fatigue, loss of coordination and balance, numbness, blurred vision and blindness and paralysis.
What is the name for the disease caused by the loss of myelin in the PNS?
Guillain-Barre syndrome.
Which neuroglia maintain tight junctions between endothelial cells in capillary walls to form the blood brain barrier?
Astrocytes.
Astrocytes maintain what type of junctions in the blood brain barrier?
Tight junctions.
The presence of the blood brain barrier means that capillaries are …………….. ……………..?
…selectively permeable.
What can and cannot pass through the blood brain barrier?
Small molecules, e.g. glucose and amino acids can pass through, but large molecules such as cells and large proteins cannot.
The blood brain barrier is NOT effective for ………… and ………-soluble substances.
Why is this important in intravenous drug development?
Gases, fat.
Examples of fat-soluble substances include alcohol, anaesthetics and nicotine.
White blood cells are kept out of the CNS by the ………… ………… …………., maintaining its ………………….. privilege. This means that no inflammatory response is produced to any ……………….. .
Blood brain barrier, immunological, antigens.
Which laminae of the spinal cord receive painful information?
Laminae I and II.
Which laminae of the spinal cord receive non-painful information?
Laminae III - VI.
What connects the laminae, passing information deeper into the spinal cord?
Interneurones.
Describe the somatomotor pathway.
Afferent (sensory) fibres from the skin, muscle etc. have their cell bodies in the dorsal root ganglia. They enter the spinal cord via the dorsal roots and terminate in the grey matter of the dorsal root horn.
Efferent (motor) fibres have their cell body in the grey matter of the ventral horn, exit via the ventral root and terminate in the skeletal muscle.
What is another name for the dorsal horn?
Posterior.
What is another name for the ventral horn?
Anterior.
Which pathway sees afferent fibres from the skin and muscle with their cell bodies in the dorsal horn, entering the spinal cord at the dorsal root and terminating in the grey matter of the dorsal horn.
The efferent fibres have their cell body have their cell bodies in the grey matter of the ventral horn, exit via the ventral root and terminate in the skeletal muscle.
Somatomotor pathway.
Describe the visceromotor pathway.
Afferent fibres from internal organs with their cell bodies in the dorsal root ganglia enter the spinal cord via the dorsal roots and terminate in the grey matter of the dorsal horn.
The efferent fibres have their preganglionic cell body in the grey matter of the lateral horn, exit via the ventral root and terminate in the autonomic ganglion.
Which pathway is this?:
Afferent fibres from internal organs with their cell bodies in the dorsal root ganglia enter the spinal cord via the dorsal roots and terminate in the grey matter of the dorsal horn.
The efferent fibres have their preganglionic cell body in the grey matter of the lateral horn, exit via the ventral root and terminate in the autonomic ganglion.
The visceromotor pathway.
Nerves exit the spinal cord BELOW the corresponding vertebra, EXCEPT where?
C7 leaves the spinal cord above the C7 vertebra, C8 leaves the spinal cord below the C7 vertebra, setting the pattern for the rest of the spinal cord and vertebrae.
What are meninges?
Various layers of membranes which surround and protect nervous tissue.
Which is white matter and which is grey matter? Axons or cells?
White matter - axons.
Grey matter - cells.
What makes white matter look white?
White matter is axons, the myelination on the axons makes it looks white.
Which laminae are sometimes referred to as the ‘superficial laminae’?
Laminae I and II.
What is a dorsal root ganglion?
A swelling where lots of cell bodies have accumulated outside the spinal cord.
The somatic motor neuronal pools are large motor neurones which supply skeletal muscles, found at lamina…?
IX.
Which root of the spinal cord do effector neurones congregate in?
Ventral root.
Which lamina surrounds the central canal of the spinal cord?
X.
Which lamina is also called the substantia gelatinosa?
II.
Which lamina is also known as the marginal zone?
I.
Which laminae are known as the nucleus proprius, or deeper dorsal horn?
III, IV, V and VI.
Dorsal and ventral roots merge laterally to form…?
…spinal nerves.
The majority of spinal nerves are …………… nerves, composed of …………. and ……………. fibres.
Mixed, sensory, motor.
How many pairs of spinal nerves are there?
31.
Which are the only spinal nerves which do not exit the spinal cord BELOW the corresponding vertebrae?
Cervical spinal nerves.
Of the 31 pairs of spinal nerves, there are five different types. Name them.
8 -
12 -
5 -
5 -
1 -
8 - cervical.
12 - thoracic.
5 - lumbar.
5 - sacral.
1 - coccygeal.
What does ROSTRAL mean?
Towards the head end.
What does CAUDAL mean?
Towards the tail end.
There are two enlargements on the spinal cord. Name them and describe their purpose.
The cervical enlargement and lumbar enlargement contain the large numbers of motor neurones needed to supply the skeletal muscles of the arms and legs respectively.
How many layers of connective tissue protect peripheral nerves? Why?
Three. Peripheral nerves do not have the same protection as the spinal cord, so they need three layers of connective tissue to protect them.
Name the three protective layers of connective tissue surrounding peripheral nerves.
The endoneurium, perineurium and epineurium.
Which is the layer of connective tissue which surrounds individual axons in the PNS, forming a loose, delicate layer?
The endoneurium.
Which is the layer of connective tissue which encloses bundles of axons in the PNS?
The perineurium.
Which is the dense tissue layer enclosing a number of bundles of axons in the PNS as well as blood vessels?
The epineurium.
In the skull, where do nerves exit the CNS?
Via the foramina.
True or false? In humans, the spinal cord is the same length as the spine.
False. The spinal cord is significantly shorter than the spine. The spinal cord ends at the level of L1/L2 vertebrae.
Why do roots extend a significant distance caudally before emerging through the foramina - they exit pointing downwards?
The spinal cord is significantly shorter than the spine. This is called cauda equina.
Name the three meninges which cover the CNS, from outermost to innermost.
Dura mater, arachnoid mater, pia mater.
Which of the meninges is in the middle and resembles a spider’s web?
Arachnoid mater.
What is the name of the space between the arachnoid mater and the pia mater? It is filled with what fluid?
The subarachnoid space, filled with cerebrospinal fluid.
Which of the meninges is closest to the brain?
Pia mater.
What is the name of the space between the dura mater and the arachnoid mater?
Subdural space.
Name the cavities in the brain which are filled with cerebrospinal fluid.
Ventricles.
How many ventricles are there in the brain?
Four - two lateral ventricles and the third and fourth ventricles.
Name the channel which connects the lateral ventricles to the third ventricle.
The intraventricular foramina / the Foramina of Monro.
Name the channel which connects the third and fourth ventricle.
The cerebral (Sylvian) aqueduct.
Name the two structures which connect the fourth ventricle to the subarachnoid space.
The Foramina of Luschka (two lateral apertures) and the Foramina of Magendie (a medial aperture).
Most (70%) cerebrospinal fluid is produced where?
By chloroid plexuses in the walls and roofs of ventricles.
What is produced in chloroid plexuses?
Cerebrospinal fluid.
Tight juunctions between what type of cells in capillaries form the CSF-blood barrier?
Ependymal cells.
Which fluid is similar to plasma, being made of glucose and various ions, but without proteins?
Cerebrospinal fluid.
The movement of CSF is said to be…?
…pulsatile.
What are the roles of CSF in the CNS?
To protect and cushion the CNS and give the brain buoyancy. CSF provides nutrition and removes waste products.
What follows this path through the CNS?
Ventricles - cisterna magna (subarachnoid space) - arachnoid villi - venous (dural) sinuses.
CSF.
What is also known as the cisterna magna?
Subarachnoid space.
Which structures act as one-way valves - CSF can only flow into the venous sinuses?
Arachnoid villi.
Which structures are valveless channels which are supplied with CSF by the brain’s venous system and ultimately drain into internal jugular veins?
Venous sinuses.
What are the differences between the dura mater in the head and in the spinal cord?
In the head:
Double layer.
Attache to inside of skull.
No epidural space between dura mater and skull.
In the spinal cord:
Single layer.
Epidural space above contains venous plexuses.
Very thin subdural space containing interstitial fluid.
Does the dura mater contain any nerves or have a blood supply?
Yes, it is highly innervated and vascularised.
Does the arachnoid mater have a blood supply?
No.
Name the large cavities found in the subarachnoid space.
Cisterns.
The pia mater contains small plexuses of blood vessels. What is their purpose?
To supply oxygen and nutrients to the CNS.
Which illness is a bacterial or viral infection of the meninges?
Meningitis.
Describe the causes and treatment of hydrocephalus.
Hydrocephalus is caused by overproduction of CSF. The flow between ventricles is blocked and drainage into the circulatory system is blocked. This leads to increased intracranial pressure and in newborns the skull expands.
Treatment is by insertion of a shunt to drain the excess CSF.
