This packet applies the full six-rubric system to the nervous-system unit of an undergraduate A&P lab. The dissection rubric is most concrete here, sheep brain dissection has a longer list of observable technique criteria than most A&P specimens.
By the end of the nervous-system unit, a student should be able to:
Brain regions, cranial nerves, spinal cord (Pages 2–4)
Same items as R1, paired with function (Page 5)
Multipolar neurons, astrocytes, oligodendrocytes, myelin (Page 6)
Sheep brain dissection, observed live (Page 7)
Weekly checklist applied across the 3-week unit (Page 8)
Nervous-system stations on the term-end practical (Page 9)
Sheep brain is the specimen most easily destroyed by a single bad cut, the corpus callosum, the ventricles, and the diencephalic structures all sit in the path of an over-eager midsagittal section. The R4 rubric is therefore stricter on tool discipline and orientation than the cardiovascular packet's. Students who pass R4 here can generally pass it in any other A&P unit.
Identification of brain regions on a midsagittal model or a midsagittally-sectioned sheep brain. Pre-approved synonyms pass; the spelling column shows the discriminator on common confusions.
| Canonical answer | Accepted synonyms | Spelling rule / common confusion |
|---|---|---|
| Cerebrum & cerebral structures | ||
| Frontal lobe | (none) | Lobe required; "frontal" alone → not yet |
| Parietal lobe | (none) | "Parital" passes (phonetic) |
| Temporal lobe | (none) | Confusion with the temporal bone → not yet on this slide |
| Occipital lobe | (none) | "Occipital" must include "lobe" |
| Insula | Insular cortex, island of Reil | — |
| Central sulcus | Central fissure, fissure of Rolando | Distinguish from longitudinal fissure → not yet (different feature) |
| Precentral gyrus | Primary motor cortex | Functional name accepted as synonym |
| Postcentral gyrus | Primary somatosensory cortex | Functional name accepted as synonym |
| Corpus callosum | (none) | "Corpus calossum" passes (phonetic) |
| Longitudinal fissure | Interhemispheric fissure | Distinguish from central sulcus → not yet |
| Diencephalon | ||
| Thalamus | (none) | Distinguish from hypothalamus → not yet (different region) |
| Hypothalamus | (none) | Same rule |
| Pineal gland | Pineal body, epiphysis cerebri | "Pinneal" passes (phonetic); confusion with pituitary → not yet |
| Pituitary gland | Hypophysis | If the gland is detached on the specimen, "stalk" is acceptable as "infundibulum" |
| Optic chiasm | Optic chiasma, optic decussation | "Optic chasm" → not yet (different word) |
| Brainstem & cerebellum | ||
| Midbrain | Mesencephalon | — |
| Pons | (none) | "Ponz" passes (phonetic) |
| Medulla oblongata | Medulla | "Medula" passes (phonetic) |
| Cerebellum | "Little brain" (informal but recognized) | "Cerebrum" → not yet (different structure) |
| Vermis (cerebellar) | Cerebellar vermis | — |
| Arbor vitae | Tree of life (informal) | — |
| Ventricles & CSF spaces | ||
| Lateral ventricle | First/second ventricle | Side optional unless pin specifies |
| Third ventricle | (none) | — |
| Cerebral aqueduct | Aqueduct of Sylvius, mesencephalic aqueduct | — |
| Fourth ventricle | (none) | — |
| Choroid plexus | (none) | "Coroid plexus" passes (phonetic) |
Each cranial nerve is graded on three judgments: Roman numeral, name, and primary function. A pin can be set to require any one, two, or all three; the score sheet specifies. The full table is the canonical reference TAs grade against.
| # | Name | Primary function (any one acceptable) | Spelling / sensory–motor–both |
|---|---|---|---|
| I | Olfactory | Smell · olfaction | Sensory · "Olfactary" passes |
| II | Optic | Vision · sight | Sensory · — |
| III | Oculomotor | Most extraocular eye movements · pupil constriction · lens accommodation | Motor · "Occulomotor" passes |
| IV | Trochlear | Superior oblique muscle (eye) · downward and lateral eye movement | Motor · "Trochelar" passes |
| V | Trigeminal | Facial sensation (V1, V2, V3 divisions) · mastication (V3 motor) | Both · "Trigeminus" passes |
| VI | Abducens | Lateral rectus (eye) · lateral eye movement | Motor · "Abducents" passes |
| VII | Facial | Facial expression · taste (anterior 2/3 of tongue) · lacrimation · salivation | Both · — |
| VIII | Vestibulocochlear | Hearing · balance / equilibrium | Sensory · "Vestibulocochlear" or "auditory" or "vestibular nerve" all accepted |
| IX | Glossopharyngeal | Taste (posterior 1/3 of tongue) · swallowing · salivation (parotid) · BP/CO2 sensing (carotid body/sinus) | Both · "Glosso-pharyngeal" with hyphen passes |
| X | Vagus | Parasympathetic innervation of thoracic and abdominal viscera · heart rate · digestion · vocalization | Both · — |
| XI | Accessory | Sternocleidomastoid · trapezius · head and shoulder movement | Motor · "Spinal accessory" accepted |
| XII | Hypoglossal | Tongue movement · speech and swallowing | Motor · "Hypogloseal" passes |
If a student writes a mnemonic ("On Old Olympus' Towering Tops...") instead of the answer, that is not yet. The mnemonic is a study aid; the rubric is for the named answer.
| Canonical answer | Accepted synonyms | Spelling rule / common confusion |
|---|---|---|
| Spinal cord cross-section | ||
| Gray matter | Grey matter | Confusion with white matter → not yet (location: gray inner H, white outer) |
| White matter | (none) | Same rule |
| Dorsal (posterior) horn | Posterior horn | Distinguish from ventral horn → not yet |
| Ventral (anterior) horn | Anterior horn | Same rule |
| Lateral horn | (none) | Only present in thoracolumbar segments — verify level |
| Central canal | (none) | — |
| Dorsal root | Posterior root | Sensory afferents |
| Ventral root | Anterior root | Motor efferents |
| Dorsal root ganglion | Posterior root ganglion, spinal ganglion, DRG | — |
| Meninges | ||
| Dura mater | Dura | Outermost; "tough mother" translation acceptable as recognition |
| Arachnoid mater | Arachnoid | "Arachnoid membrane" accepted |
| Pia mater | Pia | Innermost, adheres to cord surface |
For the monosynaptic reflex arc (e.g. patellar reflex):
Many students insert "the brain" into the monosynaptic reflex arc. The brain is not part of the arc, that's the entire point of the reflex (faster than conscious thought). If the student writes the arc with a brain step, that's not yet, and the coaching note on the score sheet should be: "the reflex bypasses the brain, what makes it fast?"
| Structure | Acceptable function statements (any one is sufficient) | What does NOT pass |
|---|---|---|
| Frontal lobe | Higher-order executive function · voluntary motor control (precentral gyrus) · personality and decision-making · Broca's area (speech production, dominant hemisphere) | "Thinking" alone (too vague) |
| Occipital lobe | Primary visual processing · interpretation of visual input from the optic radiations | "Sees" alone (must indicate processing/interpretation) |
| Cerebellum | Coordination of voluntary movement · balance · motor learning · timing of movement | "Movement" alone (must indicate coordination, not initiation) |
| Thalamus | Relay station for sensory input (except smell) to the cerebral cortex · gating and modulating sensory information | "Relay" alone (must indicate sensory and direction) |
| Hypothalamus | Homeostasis: temperature, hunger, thirst, autonomic regulation · endocrine control via the pituitary · circadian rhythm | "Hormones" alone (too vague) |
| Pituitary gland | Master endocrine gland; releases hormones controlling other endocrine glands · anterior secretes its own hormones, posterior releases hypothalamic hormones | "Makes hormones" alone (must indicate master role or hypothalamic relationship) |
| Pineal gland | Secretes melatonin · regulates circadian rhythm and sleep–wake cycle | "Sleep" alone (must indicate melatonin or circadian) |
| Medulla oblongata | Cardiovascular center, respiratory center, vomiting reflex · regulation of involuntary visceral functions | "Breathing" alone (acceptable shorthand only — escalate) |
| Pons | Bridge between cerebral cortex and cerebellum · respiratory rhythm modulation · sleep regulation | "Bridge" alone (must indicate what is bridged or function) |
| Corpus callosum | Connects the two cerebral hemispheres · allows interhemispheric communication and coordination | "Connects the brain" alone (must indicate hemispheres) |
| Choroid plexus | Produces cerebrospinal fluid (CSF) within the ventricles | "In the brain" alone → not yet |
| Dorsal root ganglion | Contains cell bodies of sensory (afferent) neurons entering the spinal cord | "Nerve cells" alone (must indicate sensory) |
| Ventral horn (gray matter) | Contains cell bodies of motor (efferent) neurons exiting the spinal cord | Confusion with dorsal horn → not yet |
| Vagus nerve (CN X) | Parasympathetic innervation of thoracic and abdominal viscera; slows heart rate; promotes digestion | "Vagus" alone (must indicate parasympathetic or specific organ) |
| Trigeminal nerve (CN V) | Sensation from the face (three divisions: V1 ophthalmic, V2 maxillary, V3 mandibular); motor to muscles of mastication | "Face" alone (must indicate sensation) |
| Slide | Canonical identification | Two features required (any two from list) |
|---|---|---|
| Multipolar neuron (smear, e.g. spinal cord ventral horn) | Multipolar neuron / motor neuron | Large cell body (soma) · Single axon · Multiple dendrites radiating from the soma · Prominent nucleus with conspicuous nucleolus · Nissl bodies visible in the cytoplasm |
| Astrocytes (e.g. silver-stained brain section) | Astrocyte | Star-shaped morphology · Multiple radiating processes · Foot processes contacting capillaries (if visible) · Located in CNS (gray or white matter context) |
| Myelinated nerve fiber (cross-section, peripheral nerve) | Myelinated peripheral nerve fiber / cross-section of peripheral nerve | Round axons surrounded by clear (washed-out) myelin sheath · Schwann cell nuclei at the periphery of myelin · Bundles (fascicles) of axons surrounded by perineurium · Endoneurium between individual fibers |
| Cerebellar cortex | Cerebellar cortex | Three distinct layers: molecular (outer), Purkinje cell (middle, single row of large cells), granular (inner, densely packed small cells) · Purkinje cells with elaborate dendritic arbors extending into molecular layer · Folia (folds) of cortex visible at low magnification |
Process is observed live during the lab session. The TA circulates with this clipboard; the student is not interrupted. The decision is made at the end of the dissection.
Sheep brains are an annual order. A student who routinely destroys structures during dissection isn't just failing R4, they are depleting the cohort's shared resource. The repeat-on-second-specimen rule is one per student per term for that reason. A student who cannot pass on the second attempt is referred to a one-on-one coaching session before any further attempt is granted.
Applied each week of the unit. The notebook is reviewed at the bench at the end of the lab session; no take-home grading. The same six-item rubric is used across all units; what changes is the content the notebook documents.
The nervous-system unit is the one where most students will encounter the cranial-nerve and reflex examinations as the closest analog they have yet seen to a clinical workup. The notebook should include the student's own results and their partner's, recorded contemporaneously, with a brief comparison. This creates the small dataset the capstone (R6) integration question can draw on.
The nervous-system unit contributes 4 stations to the term-end capstone. Each station is 90 seconds and tests four judgments: identification, function, clinical context, and cross-system integration. The station passes at 3 of 4; excellence is 4 of 4.
Identification (per R1). Function (per R2). Clinical: name one pathology associated with the structure (e.g. "thalamic stroke," "cerebellar ataxia," "pituitary adenoma"). Integration: relate to another organ system (e.g. "hypothalamus controls anterior pituitary which controls thyroid").
Identification: Roman numeral + name from a labeled diagram or model. Function: primary function (per R2). Clinical: state one bedside test used to assess the nerve (e.g. "shrug shoulders for CN XI," "stick out tongue for CN XII"). Integration: relate to a system the nerve influences (e.g. CN X to cardiovascular, CN VII to musculoskeletal of the face).
Identification: indicated structure. Function: role in afferent or efferent pathway. Clinical: state one consequence of injury at the location (e.g. "ventral horn lesion → flaccid paralysis"). Integration: relate to muscular or sensory system as appropriate.
Performance station. Identification: name the reflex or nerve being tested. Function: explain what intact response demonstrates. Clinical: one normal/abnormal interpretation (e.g. "patellar reflex absent in L3 nerve root injury"). Integration: the same response under conditions that alter autonomic state (recent caffeine, recent exercise).
| Outcome per station | Counted as |
|---|---|
| 4 / 4 | Excellence (counts toward A bundle) |
| 3 / 4 | Pass (counts toward B and C bundles) |
| ≤ 2 / 4 | Not yet (counts toward D bundle if attempted; no F-bundle credit) |
| No attempt | Not counted toward any bundle |
Student: ______________________________________ Section: _______________ Date: _______________ TA: _______________
| # | Item | ID (R1) | Function (R2) | Notes |
|---|---|---|---|---|
| 1 | Brain region (cerebral) | P / NY | P / NY / — | |
| 2 | Brain region (diencephalic) | P / NY | P / NY / — | |
| 3 | Brainstem region | P / NY | P / NY / — | |
| 4 | Cerebellar feature | P / NY | P / NY / — | |
| 5 | Ventricle / CSF feature | P / NY | P / NY / — | |
| 6 | Cranial nerve (Roman + name + function) | P / NY | — | 3 sub-judgments combine to one decision |
| 7 | Cranial nerve (Roman + name + function) | P / NY | — | |
| 8 | Spinal cord cross-section structure | P / NY | P / NY / — | |
| 9 | Reflex arc sequencing | P / NY | — |
| # | Slide | ID | ≥2 features | Notes |
|---|---|---|---|---|
| 10 | Multipolar neuron | P / NY | P / NY | |
| 11 | Cerebellar cortex or peripheral nerve | P / NY | P / NY |
| Item | Criterion | Met |
|---|---|---|
| D1 | Pre-dissection inspection completed | P / NY |
| D2 | Tools used appropriately (probe + scalpel only) | P / NY |
| D3 | Midsagittal cut in the longitudinal fissure | P / NY |
| D4 | Internal structures preserved and identifiable | P / NY |
| D5 | Cleanup and storage per protocol | P / NY |
| R4 | Overall (5 of 5 = pass) | P / NY |
☐ No ☐ Yes, for item: __________ Tokens remaining: ☐ 3 ☐ 2 ☐ 1 ☐ 0
P = Pass · NY = Not yet · — = Not assessed · Edge cases: circle, do not check, bring to coordinator at end of session.