sp14_-_human_anatomy_exam_1_20141210195148 Flashcards
What is the bony structure surrounding the brain?
skull
What is the bony structure surrounding the spinal cord?
vertebral canal
How many angular degrees separate the horizontal plane from the coronal plane?
90 degrees
What type of muscle is innervated by fibers of the somatic nervous system?
striated muscle
What are the 3 major embryological subdivisions of the brain?
- rhombencephalon - most caudal subdivision and consists of: myelencephalon (medulla oblongata) and metencephalon (pons and cerebellum)- mesencephalon - midbrain- prosencephalon - cerebrum including diencephalon (“in-between” brain) and telencephalon (cerebral hemispheres and corpus striatum of the basal ganglia)
What are the minor subdivisions of the hindbrain?
- myelencephalon - medulla oblongata- metencephalon - pons and cerebellum
What are the minor subdivisions of the forebrain?
- diencephalon - “in-between brain”- telencephalon - cerebral hemispheres, corpus striatum of the basal ganglia
What are the ventricular cavities of each subdivision of the brain?
- spinal cord - central canal- rhombencephalon - 4th ventricle- midbrain - cerebral aqueduct- diencephalon - 3rd ventricle- telencephalon - lateral ventricles (1st and 2nd)
What is the structural and functional unit of the nervous system?
neuron
List the 12 cranial nerves by name and number.
CN I - olfactoryCN II - opticCN III - oculomotorCN IV - trochlearCN V - trigeminal (ophthalmic, maxillary, and mandibular)CN VI - abducensCN VII - facialCN VIII - vestibulocochlearCN IX - glossopharyngealCN X - vagusCN XI - accessoryCN XII - hypoglossal
What are the components of the brainstem?
- midbrain- pons- medulla
Name the lobes of the cortex.
- frontal lobe- occipital lobe- temporal lobe- parietal lobe
What are the borders of the frontal lobe?
lobe lies rostral to the central sulcus and superior to the lateral fissure
What are the borders of the occipital lobe?
lobe lies behind an imaginary line drawn from the parieto-occipital sulcus to the preoccipital notch
What are the borders of the temporal lobe?
lobe lies below the lateral fissure and an imaginary extension drawn caudally to the occipital lobe
What are the borders of the parietal lobe?
lobe occupies the remainder of the lateral surface not covered by another lobe
Define ipsilateral.
the axon (tract) courses and/or terminates on the same side as its cell body (nucleus)
Define contralateral.
the axon (tract) courses and/or terminates on the side opposite its cell body (nucleus)
Define bilateral.
the axon (tract) divides and courses and/or terminates on both sides
Define decussation.
fibers ascend/descend as they cross
Define commissure.
fibers pass directly from one side to the other
List the 3 meninges.
- dura mater- arachnoid- pia mater
List and describe the 2 clinically significant potential meningeal spaces.
- epidural space - potential space between the skull and dura mater- subdural space - potential space between the dura mater and the arachnoid**subarachnoid space is an actual space, not a potential space (?)
What is an epidural hematoma?
result of blood entering the epidural space; often the result of damage to the middle meningeal artery; the expanding hematoma puts pressure on the brain
What is a subdural hematoma?
result of blood entering the subdural space; often the result of damage to small veins that cross from the brain to the venous sinuses; the expanding hematoma puts pressure on the brain
What is the major blood supply to the dura over the parietal lobe?
the middle meningeal artery and its branches (?)
What is the rostral extent of the subarachnoid space along the optic nerve? How is this clinically significant?
meninges cover the optic nerve so the subarachnoid space extends along the optic nerve to the back of the eye; an abnormal increase in CSF pressure (hydrocephalus) is reflected by changes in the optic papilla (choked disk; papilledema)
What is the falx cerebri and what does it separate?
- it is a reflection of dura mater- extends ventrally in the sagittal plane from the skull to the corpus callosum and separates the cerebral hemispheres; the superior sagittal sinus occupies the upper edge of the falx
What is the tentorium cerebelli and what does it separate?
- it is a reflection of dura mater- lies horizontally to separate the cerebellum below from the occipital lobe above; tentorium extends around the brainstem; the opening created by the brainstem is called the tentorial incisure (notch) and is occupied by the midbrain
What occupies the supratentorial compartment? The infratentorial compartment?
- supratentorial compartment - cerebrum- infratentorial compartment - cerebellum
What is the origin, course, and point of resorption of cerebrospinal fluid?
- cerebrospinal fluid (CSF) is produced by vascular tufts located in the lateral, third, and fourth ventricles- CSF exits the ventricular system into the subarachnoid space- CSF is reabsorbed into the superior sagittal siinus through the arachnoid granulations
Name the vessels involved in the posterior (vertebral-basilar) blood supply of the brain.
- posterior inferior cerebellar artery- anterior inferior cerebellar artery- superior cerebellar artery- posterior cerebral artery
Name the vessels involved in the anterior (internal carotid) blood supply of the brain.
- anterior cerebral artery (with the anterior communicating artery)- middle cerebral artery (with ophthalmic artery)- posterior communicating artery (connects ICA with posterior cerebral artery)
Name the vessels of the cerebral arterial circle (of Willis).
- anterior cerebral artery- anterior communicating artery- middle cerebral artery- internal carotid artery- posterior communicating artery- posterior cerebral artery- superior cerebellar artery- basilar artery- anterior inferior cerebellar artery- posterior inferior cerebellar artery- vertebral artery- anterior spinal artery
Name the 3 major vessels that supply the cerebral cortex.
- anterior cerebral artery- middle cerebral artery- posterior cerebral artery
Name each of the four functional components found in a peripheral nerve and describe their functions.
- somatic afferent - pain, touch, temperature, and position sense- somatic efferent - motor signals that control striated muscles- visceral afferent - “visceral sensibility” like peristaltic activity, blood pressure, bladder fullness, etc.- visceral efferent - autonomic nervous system; two neurons linked together
What tissues are innervated by somatic afferent neurons?
skin (pain, touch, temperature, conscious proprioception, awareness of limb position)
What tissues are innervated by somatic efferent neurons?
striated (voluntary) muscles
What tissues are innervated by visceral efferent neurons?
contraction of smooth muscle and secretion of glands; preganglionic and postganglionic neuron chains
What tissues are innervated by visceral afferent neurons?
organs to monitor internal environment like heart rate, blood pressure, smooth muscle contractility, and bladder/bowel fullness
What is the location of the preganglionic nerve cell bodies? The postganglionic nerve cell bodies?
- preganglionic - nerve cell body in CNS; axon extends to autonomic ganglion- postganglionic - nerve cell body in autonomic ganglion; axon extends to visceral target
What are the functional components and target tissue of nerve fibers found in the posterior root?
- functional component - sensory (somatic afferent and visceral afferent)- target tissue - skin, internal organs
What are the functional components and target tissue of nerve fibers found in the anterior root?
- functional component - motor (somatic efferent)- target tissue - striated muscle, internal organs
What is the functional component and target tissue of nerve fibers found in the posterior ramus?
- functional component - sensory and motor- target tissue - back
What is the functional component and target tissue of nerve fibers found in the anterior ramus?
- functional component - sensory and motor- target tissue - anterior and lateral body as well as limbs
What is the function and relative speed of an A-alpha afferent nerve fiber?
- function - myotatic reflex- velocity - 70-120 m/sec
What is the function and relative speed of an A-beta nerve fiber?
- function - deep touch- velocity - 60-80 m/sec
What is the function and relative speed of an A-delta nerve fiber?
- function - light touch, fast pain- velocity - 10-30 m/sec
What is the function and relative speed of a C nerve fiber?
- function - slow pain- velocity - 0.5-2.5 m/sec
List the events seen during the degeneration of a nerve fiber.
- if an axon is crushed (or cut), the axon distal to the crush will degenerate- the axon proximal to the crush will die back a short distance- the cell body will respond by becoming more metabolically active (chromatolysis)- the axon and myelin degenerate (but not Schwann cells) and macrophage cells engulf the debris
List the events seen during the regeneration of a nerve fiber.
- axons sprout and exhibit growth cones- Schwann cells undergo mitosis and form guiding route for the growth cone- Schwann cells produce new myelin- greater number of Schwann cells means: shorter internodal distance and slower conduction time
What is the “knee jerk” reflex? How does it work? How is it modified?
- when the muscle is stretched (by hitting the knee), the neuromuscular spindle is also stretched- A-alpha sensory fiber conducts stretch signal back to spinal cord- sensory fiber has a single synapse with an alpha motor neuron which moves the extrafusal muscle fibers to move the limb- this is monosynaptic and cannot be modified
What is the lower motor neuron?
the nerve cell body (located in the CNS) and its axon (located in the PNS) that innervates a striated muscle
What are the signs and symptoms of a lower motor neuron lesion?
- flaccid paralysis- atonia - loss of normal muscle tone- areflexia - loss of the stretch (myotatic) reflex- fasciculations - spontaneous contraction of bundles of muscle fibers- muscle atrophy
A lower motor neuron lesion results form a lesion of what?
- peripheral nerve- anterior root- anterior horn motor neurons
What is muscle tone?
slight contraction of the muscles that does not produce movement or active resistance, but gives the muscles firmness, assisting the stability of joints and the maintenance of posture
What is the neuroanatomical basis of muscle tone?
the activation of the gamma and alpha motor neurons
What are the functional components and target tissue of nerve fibers found in the anterior root?
- functional component - motor (somatic efferent)- target tissue - striated muscle, internal organs
Name the 3 funiculi of the spinal cord.
- posterior funiculus- lateral funiculus- anterior funiculus
Name the four sulci.
- posterior median sulcus- posterior intermediate sulcus- posterolateral sulcus- anterolateral sulcus
What is the caudal extent of the posterior intermediate sulcus?
posterior intermediate sulcus only extends to level T6 so that is the caudal extent
What 2 bundles of fibers are separated by the posterior intermediate sulcus?
- fasciculus gracilis- fasciculus cuneatus
Name the cord levels between which the lateral horn is found.
T1-L2
Name the two structures that stabilize the spinal cord within the vertebral canal.
- denticulate ligaments - extend from the cord through the arachnoid to the dura- spinal nerves - anchor the cord in the vertebral canal
Name the sensory function modulated by Lamina II.
pain (substantia gelatinosa)
In what direction are the impulses traveling that are found in the posterior root? In the anterior root? In the spinal nerve?
- posterior root - carries sensory signals toward the cord- anterior root - carries motor signals away from the cord- spinal nerve - carries signals toward and away from the cord
What is the posterior root ganglion?
found along the posterior root; contains the neuron cell bodies of the nerve fibers that make up the posterior root
What part of the body (soma) is served by the nerve fibers that make up the posterior ramus? The anterior ramus?
- posterior ramus - serves posterior aspect of the body- anterior ramus - serves anterior aspect of the body
Are the anterior and posterior rami sensory in function? Motor in function?
The anterior and posterior rami are both sensory and motor in function since they carry fibers from the posterior and anterior roots.
Why are the communicating rami described in terms of colors (gray and white)? What function do these rami serve?
- gray matter is made up of neuron cell bodies- white matter is made up of myelinated axons- the gray and white communicating rami contain autonomic fibers and branch off the spinal nerve at T1-L2
Name the nerve fibers that make up the cauda equina.
posterior and anterior roots; occupies the lumbar cistern
Name the vertebral level that marks the caudal extent of the conus medullaris.
the caudal cone-shaped end of the spinal cord; extends to the L1-L2 interspace
Name the tissue that makes up the denticulate ligaments.
pia and arachnoid
Name the tissue that makes up the filum terminale.
pia and arachnoid that extend from the conus medullaris which is eventually encased in dura
What is contained within the lumbar cistern?
cauda equina and cerebrospinal fluid, along with the filum terminale
Name the embryological origin of the nucleus pulposus and the clinical significance of this structure.
- nucleus pulposus is a remnant of the notochord- nucleus herniates through the break in the annulus fibrosus and puts pressure on nearby nerve fibers
a, b
a. nucleus gracilis b. nucelus cuneatus
c, d
c. trigeminal spinal nucleus d. gracilis tract
e, f
e. cuneate tract f. trigeminal spinal tract
g, h
g. medial lemniscus h. pyramidal tract
a, b
a. cuneate nucleus b. trigeminal spinal nucleus
c, d
c. solitary nucleus d. dorsal motor nucleus of the vagus
e, f
e. hypoglossal nucleus f. cuneate tract
g, h
g. trigeminal spinal tract h. solitary tract
i, j
i. medial lemniscus j. pyramidal tract
a, b
a. vestibular nuclear complex b. cochlear nucleus
c, d
c. solitary nucleus d. inferior olive
e, f
e. trigeminal spinal tract f. solitary tract
g, h
g. medial lemniscus h. pyramidal tract
i, j
i. medial longitudinal fasciculus j. inferior cerebellar peduncle
a, b
a. abducens nucleus b. facial nucleus
c, d
c. inferior olive d. inferior cerebellar peduncle
e, f
e. middle cerebellar peduncle f. superior cerebellar peduncle
g, h
g. medial lemniscus h. pyramidal tract
i, j
i. medial longitudinal fasciculus j. fourth ventricle
a, b
a. trigeminal motor nucleus b. trigeminal principal sensory nucleus
c, d
c. trigeminal mesencephalic nucleus d. medial lemniscus
e, f
e. medial longitudinal fasciculus f. middle cerebellar peduncle
g, h
g. pyramidal tract h. superior cerebellar peduncle
i, j
i. trigeminal mesencephalic tract j. trigeminal nerve root
k, m
k. basilar pons m. fourth ventricle
a, b
a. periaqueductal gray b. inferior colliculus
c, d
c. superior cerebellar peduncle d. medial longitudinal fasciculus
e, f
e. medial lemniscus f. lateral lemniscus
g, h
g. basilar pons h. cerebral aqueduct