Neuroanatomy

Question 1

Differentiate between the Central and Peripheral Nervous System.

Answer 1

Central- Brain and Spinal Cord

Peripheral- Cauda Equina and Peripheral Nerves.

Question 2

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).

Answer 2

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.

Question 3

Layout of the Meningeal layers and the ventricle system of the brain and circulation of cerebrospinal fluid.

Answer 3

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.

Question 4

Anatomic position and functions of the diencephalon structures ( thalamus and hypothalamus) and the brainstem.

Answer 4

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

Question 5

Olfactory nerve

Answer 5

Sense of smell

Question 6

Optic nerve

Answer 6

Vision

Question 7

Oculomtor nerve

Answer 7

eye movement and pupil control

Question 8

Trochlear nerve

Answer 8

assists in eye movement

Question 9

Trigeminal nerve

Answer 9

Chewing muscles and some sensation in face/teeth

Question 10

Abducens nerve

Answer 10

Lateral movement of eyes

Question 11

Facial nerve

Answer 11

Control muscles of facial expressions around eye and mouth

Question 12

Vestibulocochlear nerve

Answer 12

hearing and balance

Question 13

Glossopharyngeal nerve

Answer 13

muscles for swallowing and some taste sensation

Question 14

Vagus nerve

Answer 14

autonomic function and vocal cords

Question 15

Accessory nerve

Answer 15

Shoulder shrug muscles

Question 16

Hypoglossal nerve

Answer 16

tongue muscle

Question 17

Middle cerebral arteries profuses

Answer 17

Profuse lateral cortex of brain (MN/UN)

Question 18

Anterior cerebral arteries profuses what

Answer 18

Profuse medial cortext and frontal lobe (PTN)

Question 19

Vertebral arteries profuses what

Answer 19

Travel up the tranverse foramina of the cervical vertebrae and enter the foramen magnum, then go anteriorly and combine to form the Basilar Artery

Question 20

Basilar Artery profuses what

Answer 20

Travels up the ventral surface of the pons and gives off branches to the cerebellum, pons, midbrain, thalamus and terminates into the posterior cerebrals

Question 21

Superior Cerebellar profuses what

Answer 21

superior cerebellum

Question 22

Anteriror Inferior Cerebellar profuses what

Answer 22

Inferior cerebellum and the internal auditory artery to inner ear

Question 23

Posterior Inferior Cerebellars profuses what

Answer 23

Inferior cerebellum and part of the medulla, arises from Vertebral arteries near the vertebrobasilar junction

Question 24

Anterior and Posterior Communicating arteries profuses what

Answer 24

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

Question 25

Anatomy of the spinal cord

Answer 25

``` Spinal Cord- extends from skill down to L2. 8 Cervical 12 thoracic 5 Lumbar 5 Sacral ```

Question 26

Anterior Spinal Artery

Answer 26

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.

Question 27

Posterior Spinal Arteries

Answer 27

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

Question 28

Redicular (Segmental Arteries)

Answer 28

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.

Question 29

Grey matter

Answer 29

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.

Question 30

White matter

Answer 30

surround the central grey area of the spinal cord and consists of ascending and descending tracts (sensory up, motor down) of myelinated axons.

Question 31

Dorsal Root

Answer 31

incoming sensory impulses to the spinal cord and up. Dorsal root ganglion contains sensory cell bodies.

Question 32

Ventral Root

Answer 32

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.

Question 33

Conus Medullaris

Answer 33

tapering tip of the spinal cord; from about T11 to L2

Question 34

Somatosensory- proprioception sensory up to the brain: PTN

Answer 34

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)

Question 35

Somatosensory- proprioception sensory up to the brain: MN

Answer 35

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.

Question 36

Spinothalamic tracts

Answer 36

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.

Question 37

Lateral Spinothalamic tract

Answer 37

pain, temperature sensation

Question 38

Anterior Spinothalamic Tract

Answer 38

light touch, pressure

Question 39

Corticospinal Tract

Answer 39

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.

Question 40

Anatomy of the cauda equina

Answer 40

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.

Question 41

What feeds the circle of Willis

Answer 41

Carotid

Question 42

Distribution of the various plexi particularly the brachial and lumbosacral plexi.

Answer 42

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

Question 43

Anatomic position of the major peripheral nerves and the nerve root levels at which they enter/exit the spinal cord.

Answer 43

UN C8-T1, MN C5- T1, PN L4-S2, PTN L4-S3

Question 44

What are the basic components and function of a nerve cell.

Answer 44

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

Question 45

Resting membrane potential and the factors which maintain it.

Answer 45

-70 mV

Question 46

Events surrounding the generation of an action potential and its propagation along the axon including the role of myelin.

Answer 46

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.

Question 47

Events surrounding a synaptic transmission and can describe the role of neurotransmitters in producing EPSPs and IPSPs.

Answer 47

``` 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 ```