303 Neuroanatomy

How many lobes and what are their names?

6; Frontal, Parietal, Occipital, Temporal, Insula, Limbic

what are the 2 muscles of the middle ear

The Tensor tympani muscle (attached to the malleus) and the Stapedius muscle (attached to the stapes).

What are the components of the organ of Corti?

The organ of Corti includes a basilar membrane (moves), hair cells (stereocilia, a.k.a. microvilli), and a tectorial membrane (does not move).

What is the auditory tube?

A tube that connects the middle ear with the nasopharynx and equilibrates pressure.

what is the path of the vestibulocochlear nerve balance

Utricle, saccule, semi-circular canals

- Vestibular Ganglion

- Brain Stem

- Thalamus

- Parietal lobe

what is the path of the vestibulocochlear nerve hearing

- Cochlea

- Spiral Ganglion

- Brain Stem

- Thalamus (medial gen, nucleus)

- Temporal lobe

What landmarks separate the lobes?

Central sulcus, Lateral Fissure/sulcus, Superior longitudinal Sulcus/Longitudinal Fissure, and Parieto-Occipital sulcus.

What are the functions associated with each lobe?

Frontal: Executive functions, personality, decision making
Parietal: Primary sensory cortex, association cortex
Temporal: Primary auditory cortex
Occipital: Primary visual cortex
Insula: Pain, especially visceral
Limbic: Emotion, arousal, motivation, memory

Afferent versus Efferent

afferent- Conveying toward a center.
efferent- Conveying away from a center.

Afferent = Arriving information
Efferent = Exiting information

Gray versus white matter

Gray Matter = neuronal cell bodies and proximal dendrites
White Matter = myelinated axons

What are the two major arterial supplies to the brain?

Internal carotid and Vertebra Arteries

What are the three arteries of the brain?

Anterior cerebral artery (ACA), Middle cerebral artery (MCA), Posterior cerebral artery (PCA)

What areas of the cortex do these arteries serve?

ACA, the medial and superior parts of the frontal lobe, and the anterior parietal lobe;
MCA, frontal, temporal, and parietal lobes;
PCA, the occipital lobe, the inferior part of the temporal lobe

What are the three arteries of the cerebellum?

the posterior inferior cerebellar artery (PICA), the superior cerebellar artery (SCA), and the anterior inferior cerebellar artery (AICA)

What are the connecting arteries that make the Circle of Willis a circle?

The Anterior communicating (pc) and the Posterior communicating (pc)

What are the components of the blood-brain-barrier?

The BBB is composed of four main cellular elements: endothelial cells (ECs), astrocyte end-feet, microglial cells, and pericytes.

Why is the blood-brain-barrier important?

Most bacteria and toxins cannot cross into the brain tissue

How many ventricles are there and what are their names?

4; 2 lateral ventricles (right and left, one for each hemisphere), third ventricle, and fourth ventricle.

Which horns of the lateral ventricles are in what lobes of the cortex?

anterior (frontal horn), posterior (occipital horn), and inferior (temporal horn).

Where is cerebrospinal fluid made?

choroid plexus in ventricles

How does cerebrospinal fluid circulate through the ventricles?

The CSF passes from the lateral ventricles to the third ventricle through the interventricular foramen. From the third ventricle, the CSF flows through the cerebral aqueduct to the fourth ventricle.

How does cerebrospinal fluid exit the ventricular system and where does it go?

From the fourth ventricle it then goes out through the Foramen of Luschka (lateral) and Foramen of Magendie (midline) and goes into the subarachnoid space.

What are the components of the CNS?

Brain and spinal cord

What are the components of the PNS?

Cranial and peripheral nerves

What is a tract?

A bundle of axons traveling together within the CNS

What is a nerve?

A bundle of axons (plus associated connective tissue and blood vessels) located outside the brain and spinal cord

What are ganglia?

A group of neurons outside the CNS with similar function connectivity and neurotransmitters

What is a nucleus? (with regard to the nervous system)

A group of neurons within the CNS with similar function, connectivity and neurotransmitters

What is the difference between the autonomic and somatic nervous systems?

Somatic Nervous System = Afferent and efferent systems that regulate motor innervation of skeletal muscle and sensory information from the external environment
Autonomic Nervous System = Afferent and efferent systems that regulate motor innervation of smooth muscle and gland and sensory information from the internal environment.

Name the 3 meningeal layers and their function(s), what is their order superficial to deep?

Dura Mater, Arachnoid Mater, and Pia Mater. 3 main functions are to Protect, Support vascular elements, and Enclose the subarachnoid space.

Name the specializations of the dura mater and what venous structures are associated with these specializations.

Specializations:
Falx cerebri (fc), Falx cerebelli, Tentorium cerebelli (tc).

Dural (venous) sinuses, where the venous blood is collecting back to the heart:

Superior sagittal sinus (sss)
Inferior sagittal sinus (iss)
Straight sinus (ss)
Confluens ©

What structure absorbs cerebrospinal fluid and where is it found?

Arachnoid granulations, found in the Arachnoid Mater

The spinal cord is divided into how many regions?

5; Cervical, Thoracic, Lumbar, Sacral, and Coccygeal.

What are the meninges associated with the spinal cord?

pia mater, arachnoid, and dura mater

What is the general function of the dorsal horns?, ventral horns?

The dorsal horns contain the cell bodies of sensory neurons. The ventral horns contain the cell bodies of motor neurons.

What is a spinal cord enlargement?

Two regions of the spinal cord are enlarged to accommodate the greater number of nerve cells and connections needed to process information related to the upper and lower limbs

What is the cauda equina?

Parallel cluster of nerve fibers that continue from the conus medullaris at the end of the spinal cord.
cauda equina is in the dural sac

Describe the basic plan of spinal cord gray matter.

Dorsal horns, ventral horns, intermediate

Is it the same throughout the entire length of the spinal cord?

No, going down, the gray matter gets bigger.

How are tracts within the spinal cord named?

Named for origin and destination

What types of sensation synapse in the dorsal horn?

Somatic sensory

What types of motor neurons are found in the ventral horn?

Somatic motor neurons

What types of sensation synapse in the intermediate zone?

Visceral motor and sensory

What types of motor neurons are found in the intermediate zone?

Visceral motor neurons

What is a fasciculus?

Big Bundle, whole area, a region(s), of the white matter in the spinal cord.

What is a spinal segment?

The functional unit of the spinal cord = the area to/from which one set of spinal nerves is connected

What are the modalities of the dorsal roots?, ventral roots? spinal nerves?

Somatic sensory;

Somatic motor;

Somatic Afferent, Visceral Afferent, Visceral Efferent, Somatic Efferent

sensory (Ascending, afferent)

motor (Descending, efferent)

What is the cauda equina?

Cauda equina = horse tail, a bundle of spinal nerves

Define a dermatome.

Each spinal nerve innervates a specific part of the body surface called a dermatome; each dermatome contains multiple cutaneous fields

Define a motor unit.

The number of muscle fibers innervated by one alpha motor neuron

What is a plexus?

network of nerves

What regions are served by each of the plexuses?

Cervical plexus - Sensory innervation to the head and neck and motion innervation to the infrahyoid muscles and diaphragm;
Brachial plexus - upper extremity (arms);
Lumbar plexus - lower abdomen, anterior and medial thigh;
Sacral plexus - posterior thigh, leg and pelvis

What are the terminal branches (aka. nerves) of each plexus?

Cervical Plexus - Greater auricular, Lesser occipital, Transverse cervical, Supraclavicular, Phrenic, Motor innervation to the Infrahyoid muscles
Brachial Plexus - Axillary, Musculocutaneous, Median, Radial, Ulnar
Lumbar Plexus - Iliohypogastric, Ilioinguinal, Genitofemoral, Lateral cutaneous, Femoral, Obturator
Sacral Plexus - Superior gluteal, Inferior gluteal, Nerve to piriformis, Sciatic -Tibial and Common fibular, Posterior cutanteous, Pudendal

Define a reflex

A type of local processing occurring in the spinal cord.

Influenced by the brain but does not require the brain's permission.

What are the components of a reflex?

Receptor, Afferent (sensory) fiber, Interneuron in Spinal Cord, Efferent (motor) fiber, Effector

What is the difference between a mono and polysynaptic reflex?

There is no interneuron; In a mono reflex, information from stimulation goes different from the afferent fibers to the dorsal root ganglion, to the dorsal horn, then directly synapse on the motor neuron, which send its neurons to the muscle and cause the muscle to contract.

How is your brain involved in reflexes

Usually unaware; Influenced by the brain but does not
require the brain's permission.

What are the 4 essential functions of the spinal cord?

Relays sensory information from periphery to brain, Contains motor neurons, Direct (local) connections between motor and sensory information: Reflexes, Relays motor information from brain to muscles, and Relays motor information from brain to muscles.

Describe the divisions/areas of the gray matter and white matter in the spinal cord.

Gray Matter (inner layer of the spinal cord, shaped like a butterfly), White Matter (outer layer of the spinal cord). Gray Matter is divided into dorsal horns, ventral horns, and Intermediate zone. White matter has Fasciculus and
Column.

What are some of the different names for the white matter in the spinal cord?

Fasciculus, column

Do all 3 meningeal layers cover the spinal cord? How is the dura different in the vertebral canal compared to that of the cranium?

Yes; The main difference between cranial and spinal meninges is that cranial meninges are the protective coverings of the brain, consisting of channels in the dura mater between various parts of the brain called dural folds, whereas spinal meninges are the protective coverings of the spinal cord whose dura mater acts as a dural sheath. Cranial meninges has two layer of dura while spinal meninges has a single layer.

Define/describe the following:
​Conus Medullaris
​Dural Sac
​Cauda Equina

End of the spinal cord = conus medullaris;
Dura mater continues beyond spinal cord, covers cauda equina = dural sac;
Cauda equina = horse tail, a bundle of spinal nerves that continue from the conus medullaris at the end of the spinal cord.

How many regions are there in the spinal cord and what are their names. Enlargements?

5 Regions - Cervical, Thoracic, Lumbar, Sacral, and Coccygeal; 2 enlargements - Cervical and Lumbar

What types of fibers travel in the spinal cord white matter?

Ascending tracts, Descending tracts, and Commisure

Describe the blood supply of the spinal cord.

Single anterior artery and paired posterior spinal arteries

Define a spinal nerve
​What functional modalities travel in a spinal nerve
​How many pairs of spinal nerves are there?
​What is a plexus?

A paired peripheral nerve from the spinal cord; Afferent sensory axons and Efferent motor axons; 31 pairs of spinal nerves; network of nerves

Reflexes: know all of the components, efferent and afferent and if there is or isn't an interneuron e.g., tendon reflex and pain reflex.

Receptor, Afferent (sensory) fiber, Interneuron in Spinal Cord, Efferent (motor) fiber, Effector. A polysynaptic reflex like a pain reflex has a Interneuron but monosynaptic reflext like tendon reflex does not.

What are the two subdivisions of the autonomic nervous system?What are their basic functions?

Parasympathetic "Rest and Digest", sends signals to stop or slow down something
Sympathetic "Fight or Flight", sends signals to increase something

What effects does each subdivision have on heart rate, respiratory rate, gut activity, blood glucose and the size of the pupil ?

Parasympathetic, Decreased respiratory rate,Decreased heart rate, Decreased blood glucose, Constricted pupils, Busy gut;
Sympathetic Increased respiratory rate, Increased heart rate, Increased blood glucose
Dilated pupils, Relaxed gut

With regard to preganglionic parasympathetic neurons:
-Where are they found?
-What is their neurotransmitter?
-Are their axons long or short?

Preganglionic neurons are found in the brain stem and sacral cord; Their neurotransmitters are Acetylcholine; axons are long

Where will you find the parasympathetic ganglia?

Close or within the organs they innervate

With regard to ganglionic parasympathetic neurons:
-Where are they found?
-What is their neurotransmitter?
-Are their axons long or short

Ganglia associated with cranial nerves or Within the wall of the organ; Their neurotransmitters are Acetylcholine; axons short

With regard to preganglionic sympathetic neurons:
-Where are they found?
-What is their neurotransmitter?
-Are their axons long or short?

Intermediolateral cell column (IML); Acetylcholine; short

Where will you find the sympathetic chain ganglia?

The sympathetic chain is a ganglionated chain present bilaterally extending from the base of the skull to the coccyx.

With regard to ganglionic sympathetic neurons:
-Where are they found?
-What is their neurotransmitter?
-Are their axons long or short

Sympathetic chain; Norepinephrine; long

Compare and contrast the parasympathetic and sympathetic nervous systems with regard to:
location of preganglionic neurons
location of the ganglia
length of pre and postganglionic fibers
neurotransmitters

Brainstem and sacral cord/Intermediolateral cell column (IML);
Ganglia associated with cranial nerves
Within the wall of the organ/Sympathetic chain;
Long preganglionic axons and Short ganglionic axons/Short preganglionic axons and Long ganglionic axons;
Preganglionic neurons: Acetylcholine, Ganglionic neurons: Acetylcholine/Preganglionic neurons: Acetylcholine, Ganglionic neurons: Norepinephrine

Which cranial nerves have a parasympathetic component?

CN III, Oculomotor
CN VII, Facial
CN IX, Glossopharyngeal
CN X, Vagus

What are the the different regions of the brain stem?

Medulla Oblongata, Pons, Midbrain

Which is most cranial, which is most caudal?

The most cranial is the Midbrain;
The most caudal is the medulla oblongata

What other internal features are associated with the different areas of the brain stem

Medulla Oblongata: Continuous spinal cord, Two decussations: Motor and Sensory
Pons: Between Medulla Oblongata and Midbrain, Floor of 4th ventricle
Midbrain: Continuous with diencephalon

Describe the prominent surface features of each area.

Medulla Oblongata: Pyramid, Olivary eminence
Pons: Pontine fibers, Middle cerebellar peduncle
Midbrain: Crus cerebri, Tectum

What cranial nerves are associated with the different areas of the brain stem?

Medulla Oblongata: IX Glossopharyngeal, X Vagus, XI Spinal Accessory, XII Hypoglossal
Pons: V Trigeminal, VI Abducens, VII Facial, VIII Vestibulo-cochlear
Midbrain: III Oculomotor, IV Trochlear

What is the reticular formation and why is it important?

Diffuse group of neurons within the medulla oblongata and pons. Receive sensory information: somatic and visceral, not specific sensation but general awareness. Contains respiratory and cardiovascular "centers": regulates breathing and heart rate. Participates in Ascending Reticular Activating System (if damaged, cannot wake up and stay in a coma).

Going from spinal cord to brain, how many parts make up the brain stem and in what order?

3; medulla oblongata, pons, midbrain

What defines the border between the lowest part of the brain stem and the spinal cord?

Pyramidal Decussation

What part of the ventricular system is associated with the medulla oblongata?

Fourth Ventricle

What part of the ventricular system is associated with the pons?

Fourth Ventricle

What part of the ventricular system is associated with the midbrain?

cerebral aqueduct

How many cranial nerves are there?

12 pairs of cranial nerves

What are their names? What are their numbers?

I Olfactory, II Optic, III Occulomotor, IV Trochlear, V Trigeminal, VI Abducens, VII Facial, VIII Vestibulocochlear, IX Glossopharyngeal, X Vagus, XI Spinal Accessory, XII Hypoglossal

What modality are they (sensory, motor, both)?

I Olfactory Sensory, II Optic Sensory, III Oculomotor Motor, IV Trochlear Motor, V Trigeminal Both, VI Abducens Motor, VII Facial Both, VIII Vestibulocochlear Sensory, IX Glossopharyngeal Both, X Vagus Both, XI Spinal Accessory Motor, XII Hypoglossal Motor

Which cranial nerves carry special sensory information?

Olfaction (CN I, Olfactory), Vision (CN II, Optic), Hearing and balance (CN VIII, Vestibulocochlear), Taste (CN VII, IX and X, Facial, Glossopharyngeal and Vagus)

What modality are they?

Olfactory Sensory;
Optic Sensory;
Vestibulocochlear Sensory;
Facial Both;
Glossopharyngeal Both;
Vagus Both;

To what areas of the cortex do they project?

Olfactory, Temporal Lobe; Vision, Occipital; Taste, Insular cortex; Hearing and Balance, Temporal lobe

Which cranial nerve innervate the extraocular muscles?

CN III Oculomotor, CN IV Trochlear, CN VI Abducens

Which of these cranial nerve has a parasympathetic component?

CN III, Oculomotor -Constrictor pupillae, Ciliary muscles

Which cranial nerves innervate which extraocular muscles?

CN III Oculomotor: Levator palpebrae superioris, Superior rectus, medial rectus, Inferior rectus, Inferior oblique
CN IV Trochlear: Superior oblique
CN VI Abducens: Lateral rectus

Which cranial nerve innervates the muscles of mastication?

CN V, Trigeminal

Which cranial nerve innervates the muscles of facial expression?

CN VII, Facial