Neuroanatomy Flashcards
Differentiate between the Central and Peripheral Nervous System.
Central- Brain and Spinal Cord
Peripheral- Cauda Equina and Peripheral Nerves.
Gross anatomy of the brain including the location and general functions of the lobes and the cerebellum, and the topographic layout of the sensory and motor strips (the Homonculus).
Frontal- Personality and motor cortex Temporal- speech and language centers Parietal – Primary Sensory function Occipital- Visual Function Insula- located in the interior of the brain
Central Sulcus- separate motor and sensory area.
Motor Cortex- precentral gyrus
Sensory Cortex- post central gyrus
Homunculus- lower extremities from central (medial) out [PTN] Upper extremities in lateral cortex, arm, hand fingers, face (outside) Sensory and Motor strips follow this guideline.
Layout of the Meningeal layers and the ventricle system of the brain and circulation of cerebrospinal fluid.
Meninges- protective covering over the brain and spinal cord.
Pia Mater- delicate inner covering
Arachnoid- middle web-like layer
Dura Mater- outer tough layer.
Cerebrospinal Fluid- in meninges; produced by the choroid plexus within the ventricles. Circulates in and around the brain and spinal cord within the subarachnoid space to provide additional protection.
Anatomic position and functions of the diencephalon structures ( thalamus and hypothalamus) and the brainstem.
Hypothalamus- relay/integration center. Recieves info and monitors hormones, blood temp, etc.
Thalamus- Between brainstem and brain. Oval structure above the midbrain. Relay station for sensory nuclei except smell.
Brainstem- houses nuclei for 10 of 12 cranial nerves, and autonomic cardiac and respiratory centers.
Midbrain- upper brainstem CN III-IV 3,4
Pons- middle brainstem, CN V-VIII 5-8
Medulla- lower brainstem, CN IX-XII 9-12
Olfactory nerve
Sense of smell
Optic nerve
Vision
Oculomtor nerve
eye movement and pupil control
Trochlear nerve
assists in eye movement
Trigeminal nerve
Chewing muscles and some sensation in face/teeth
Abducens nerve
Lateral movement of eyes
Facial nerve
Control muscles of facial expressions around eye and mouth
Vestibulocochlear nerve
hearing and balance
Glossopharyngeal nerve
muscles for swallowing and some taste sensation
Vagus nerve
autonomic function and vocal cords
Accessory nerve
Shoulder shrug muscles
Hypoglossal nerve
tongue muscle
Middle cerebral arteries profuses
Profuse lateral cortex of brain (MN/UN)
Anterior cerebral arteries profuses what
Profuse medial cortext and frontal lobe (PTN)
Vertebral arteries profuses what
Travel up the tranverse foramina of the cervical vertebrae and enter the foramen magnum, then go anteriorly and combine to form the Basilar Artery
Basilar Artery profuses what
Travels up the ventral surface of the pons and gives off branches to the cerebellum, pons, midbrain, thalamus and terminates into the posterior cerebrals
Superior Cerebellar profuses what
superior cerebellum
Anteriror Inferior Cerebellar profuses what
Inferior cerebellum and the internal auditory artery to inner ear
Posterior Inferior Cerebellars profuses what
Inferior cerebellum and part of the medulla, arises from Vertebral arteries near the vertebrobasilar junction
Anterior and Posterior Communicating arteries profuses what
normally no flow across but will help shunt blood to a different area of the brain if there is a compromise to the circle of willis
Anatomy of the spinal cord
Spinal Cord- extends from skill down to L2. 8 Cervical 12 thoracic 5 Lumbar 5 Sacral
Anterior Spinal Artery
Runs along entire length of the ventral midline of the spinal cord. Perfuses the anterior 2/3 of the spinal cord (everything except the dorsal columns and posterior horns). Recieves blood from the vertebral artery at the top of the spinal cord , branches from the subclavian in the cervical region, intercostals arteries from the aorta in the thoracid region and lumbara arteries in the cauda equine.
Posterior Spinal Arteries
The left and right posterior spinal arteries also run along the entire length of the spinal cord and are located immediately lateral to the dorsal coumns. Like the anterior spinal artery, the posterior spinals receive blood from the vertebral, subclavian branches, intercostals and lumbar arteries
Redicular (Segmental Arteries)
Vessels at the segmental level of the spine that feed into both anterior and posterior spinal arteries Most segmentals are underdeveloped or degenerate and don’t contribute much to spinal cord perfusion. Several segmentals, however, are important for providing blood flow to the cord. One segmental is a large and crucial feeding vessel to the spinal cord—Artery of Adamkiewicz—around T10.
Grey matter
dark butterfyly-shaped pattern seen in the cross-section of the spinal cord is the grey matter which consists of unmyelinated interneurons, and cell bodies. Incoming and outgoing signals are processed in the grey matter, including all spinal reflexes. Extensions of the grey matter are called posterior and anterior horns.
White matter
surround the central grey area of the spinal cord and consists of ascending and descending tracts (sensory up, motor down) of myelinated axons.
Dorsal Root
incoming sensory impulses to the spinal cord and up. Dorsal root ganglion contains sensory cell bodies.
Ventral Root
outgoing motor impulses from the spinal cord. Lower motor neurons have their cell bodies in the anterior horn of the spinal cord and exit via the ventral root.
Conus Medullaris
tapering tip of the spinal cord; from about T11 to L2
Somatosensory- proprioception sensory up to the brain: PTN
Medial Malleolus to Popliteal Fossa to lumbosacral plexus to L4-S3 nerve roots (cauda equine) to conus medularis then up spinal cord to 1st synapse in medulla at the nucleus gracillus then crosses over then up to medial lemniscus to synapse in the thalamus then up to cortex (many synapses)
Somatosensory- proprioception sensory up to the brain: MN
wrist to anticubital space to brachial plexus to C5-T1 nerve root to spinal cord to 1st synapse in the medulla at the nucleus cunneatus then crosses over and goes up to medial lemniscus then synapse in thalamus then to cortex.
Spinothalamic tracts
go from spine to thalamus (Dermatomes)
Go in dorsal root synapse in posterior horn then goes to lateral spinothalamic tracts where it travels up in the contralateral side of spine, then synapses in thalamus then to parietal cortex.
Lateral Spinothalamic tract
pain, temperature sensation
Anterior Spinothalamic Tract
light touch, pressure
Corticospinal Tract
motor signals from motor cortex down (TcMEPS)
Motor cortex in pre central gyrus to pyramidal tract to posterior limb of the internal capsule to brainstem to medulla
At medulla 85% cross over to laterl corticospinal trace (white matter) where it does down the cord and synapses at interneurons in the anterior horn then goes to lower motor neurons and exits via the ventral root to skeletal muscles
Other 15% descend uncrossed from the medulla and go through ipsilateral anterior corticospinal tract where they stop at cervical and upper thoracic spinal levels where they cross in anterior grey horns.
Anatomy of the cauda equina
The nerve roots in the lumbar and sacral spine. Since the lumbar and sacral spinal cord segments lie up in the counus medularis region, the nerve roots from these segments must travel downward outside of the spinal segments to reach their exit points, thus forming the free standing nerve roots of the causda equina.
What feeds the circle of Willis
Carotid
Distribution of the various plexi particularly the brachial and lumbosacral plexi.
Brachial Plexi- on the right side, place erbs in supraclavicular fossa (plexi behind the clavicle. Runs from C5-T1 and includes origin for Axillary (to deltoid muscle), Radial (wrist extensor, triceps) Median (arm flexor wrist, thenar) and Ulnar (hypothenar) Nerves. Has Superior, Middle and Inferior Trunk which split into anterior and posterior.
Lumbosacral Plexus- L4-S3, Gives rise to Peroneal, Tibial and Femoral Nerves
Anatomic position of the major peripheral nerves and the nerve root levels at which they enter/exit the spinal cord.
UN C8-T1, MN C5- T1, PN L4-S2, PTN L4-S3
What are the basic components and function of a nerve cell.
Axon - Signal will transmitt along
Soma - Cell body
Axon hillock - where transmitting begins
Node of Rivera - Allow Salututory conduction
Dendrite - branches that recieve information
Myelin Sheath- schwann cells in peripheral, oligodendrocytes in CNS
Resting membrane potential and the factors which maintain it.
-70 mV
Events surrounding the generation of an action potential and its propagation along the axon including the role of myelin.
All or none potential, voltage gated ion channels closed at resting, open with a potential, Na open fast, K slow, have an absolute refractory period where cell can not transmit another potential bc hyperpolarized.
Myelin helps insulate the axon and so the electrochemical change moves more quickly along the neuron.
Events surrounding a synaptic transmission and can describe the role of neurotransmitters in producing EPSPs and IPSPs.
Neurotransmitter is released from synaptic vesicles, crosses the synaptic cleft and binds to receptors. EPSPs excite the neuron and make it more likely to fire and action potential; IPSPs inhibit the neuron. These are graded potentials. NTs- gaba- inhibitory Ach- excitatory Glycine- can be both Glutamate- excitatory
