lecture 2: fossil record...autonomic nervous system (ans) • outside of our conscious awareness •...

Lecture 2: Fossil Record

BIOL 4260 Human Evolutionary Anatomy

Lecture 18: Cranial Nerves

Somatic vs. Autonomic Nervous Systems • Autonomic nervous system

– Axons innervate the visceral organs – Afferent pathways originate in the

visceral receptors • Somatic nervous system

– Axons innervate the skeletal muscles

– Afferent pathways originate in the skeletal muscles

Autonomic Nervous System (ANS)

• Outside of our conscious awareness

•  Regulates body temperature

•  Coordinates cardiovascular, respiratory, digestive, excretory, and reproductive functions

Thoracic nerves

T1 T2 T3 T4 T5 T6 T7 T8

AUTONOMIC NERVOUS SYSTEM

THORACOLUMBAR DIVISION (sympathetic

division of ANS)

CRANIOSACRAL DIVISION (parasympathetic division of ANS)

Cranial nerves (N III, N VII, N IX,

and N X)

AUTONOMIC NERVOUS SYSTEM

Consists of 2 divisions

SYMPATHETIC (thoracolumbar)

DIVISION

PARASYMPATHETIC (craniosacral)

DIVISION

Preganglionic neurons in

lateral gray horns of spinal segments T1–L2

Preganglionic neurons in brain

stem and in lateral portion of anterior gray horns of S2–S4

Send preganglionic fibers to

Which send postganglionic fibers to

Ganglia near spinal cord

Ganglia in or near target organs

Preganglionic fibers release ACh (excitatory),

stimulating ganglionic neurons

Preganglionic fibers release ACh (excitatory),

stimulating ganglionic neurons

Target organs Target organs

Most postganglionic fibers release NE at

neuroeffector junctions

All postganglionic fibers release ACh at

neuroeffector junctions

“Fight or flight” response

“Rest and repose” response

Functional components of the ANS

The Parasympathetic Division

• Functions: – Pupil constriction – Secretion of digestive enzymes from digestive

glands –  Increased smooth muscle activity of the

digestive system – Stimulation and coordination of defecation – Contraction of the urinary bladder – Constriction of respiratory passages – Reduced heart rate – Sexual arousal

Pterygopalatine ganglion

PONS

N III

N VII

N IX

N X (Vagus)

Ciliary ganglion

Submandibular ganglion

Otic ganglion

Autonomic plexuses (see Figure 17.9)

Pelvic nerves

Lacrimal gland

Eye

Salivary glands

Heart

Lungs

Liver and gallbladder

Stomach

Spleen

Pancreas

Large intestine

Small intestine

Rectum

Kidney

Urinary bladder Scrotum Penis Ovary Uterus

S2

S3

S4

Spinal cord

Preganglionic neurons Ganglionic neurons

KEY

The Cranial Nerves

• There are 12 pairs of cranial nerves – These nerves innervate the periphery emerging

from the brain (not the spinal cord) – These nerves are on the ventrolateral surface of

the brain – They are numbered beginning at the anterior

aspect of the brain – They are numbered CN I to CN XII

The Cranial Nerves

Figure 16.22b Origins of the Cranial Nerves

Diagrammatic inferior view of the human brain. Compare view with part (a).

Olfactory bulb, termination of olfactory nerve (N I)

Olfactory tract

Optic chiasm

Optic nerve (N II)

Infundibulum

Oculomotor nerve (N III)

Trochlear nerve (N IV)

Trigeminal nerve (N V)

Abducens nerve (N VI)

Facial nerve (N VII)

Vestibulocochlear nerve (N VIII)

Glossopharyngeal nerve (N IX)

Vagus nerve (N X)

Hypoglossal nerve (N XII)

Accessory nerve (N XI)

The inferior surface of the brain as it appears on gross dissection. The roots of the cranial nerves are clearly visible.

Medulla oblongata

Spinal cord

Cerebellum

Vertebral artery

Basilar artery

Mamillary body

Pons

Olfactory bulb, termination of olfactory nerve (N I)

Olfactory tract

Optic chiasm

Optic nerve (N II)

Infundibulum

Oculomotor nerve (N III)

Trochlear nerve (N IV)


Abducens nerve (N VI)

Facial nerve (N VII)

Vestibulocochlear nerve (N VIII)

Glossopharyngeal nerve (N IX)

Vagus nerve (N X)

Hypoglossal nerve (N XII)

Accessory nerve (N XI)

The Cranial Nerves

• CN I: The Olfactory Nerve – Function: sensory (smell) – Origin: olfactory epithelium – Foramen: olfactory foramina – Destination: olfactory bulbs

Olfactory nerve fibers

Olfactory epithelium

Cribriform plate of ethmoid

OLFACTORY NERVE (N I)

Olfactory tract (to olfactory cortex

of cerebrum)

Left olfactory bulb (termination of olfactory nerve)

Figure 18.6a The Olfactory Organs

The distribution of the olfactory receptors on the left side of the nasal septum is shown by the shading.

Olfactory bulb

Olfactory nerve fibers (N I)

Olfactory tract

Cribriform plate of ethmoid

Olfactory epithelium

The Cranial Nerves

• CN II: The Optic Nerve – Function: sensory (vision) – Origin: retina – Foramen: optic canal – Destination: diencephalon, then to occipital

lobe

OPTIC NERVE (N II)

Mesencephalon (cut)

Optic chiasm

Optic tract

Eye

Visual cortex (in occipital lobes)

Optic projection fibers

Lateral geniculate nucleus (in thalamus)

Pituitary gland

Olfactory tract Olfactory bulb

The Cranial Nerves

• CN III: The Oculomotor Nerve – Function: controls extra-ocular eye muscles

•  Motor function •  Superior, inferior, and medial rectus •  Inferior oblique •  Levator palpebrae superioris

– Origin: mesencephalon – Foramen: superior orbital fissure – Destination: extra-ocular eye muscles

Trigeminal nerve (N V), cut

Vestibulocochlear nerve (N VIII), cut

Facial nerve (N VII), cut

ABDUCENS NERVE (N VI)

Lateral rectus muscle (cut)

Medial rectus muscle

Inferior rectus muscle

Ciliary ganglion

OPTIC NERVE (N II)

Optic chiasm

OCULOMOTOR NERVE (N III)

TROCHLEAR NERVE (N IV)

Superior rectus muscle Superior

oblique muscle

Trochlea

Levator palpebrae superioris

muscle

Inferior oblique muscle

The Cranial Nerves

• CN IV: The Trochlear Nerve – Function: controls extra-ocular eye muscles

•  Motor function •  Superior oblique

– Origin: mesencephalon – Foramen: superior orbital fissure – Destination: extra-ocular eye muscles








Ciliary ganglion

OPTIC NERVE (N II)

Optic chiasm




oblique muscle

Trochlea


muscle


The Cranial Nerves

• CN V: The Trigeminal Nerve – Function:

•  Mixed (sensory and motor) function •  Ophthalmic: sensations from the forehead, eyelids, and

nose •  Maxillary: sensations from lower eyelid, upper lip, and

cheek •  Mandibular: controls mastication

– Origin: ophthalmic, maxillary, and mandibular nerves

The Cranial Nerves

• CN V: The Trigeminal Nerve (continued) – Foramen:

•  Ophthalmic: superior orbital fissure •  Maxillary: foramen rotundum •  Mandibular: foramen ovale

– Destination: •  Ophthalmic and maxillary: Pons •  Mandibular: mandibular muscles

TRIGEMINAL NERVE (N V)

Maxillary branch

Foramen ovale

Pons

Otic ganglion

Mandibular branch


Ophthalmic branch

Semilunar ganglion

Superior orbital fissure

Supraorbital nerves

Ciliary ganglion

Foramen rotundum

Infra-orbital nerve

Lingual nerve


Mental nerve

The Cranial Nerves

• CN VI: The Abducens Nerve – Function: controls eye movements

•  Motor function

– Origin: pons – Foramen: superior orbital fissure – Destination: innervates the lateral rectus eye

muscle








Ciliary ganglion

OPTIC NERVE (N II)

Optic chiasm




oblique muscle

Trochlea


muscle


The Cranial Nerves

• CN VII: The Facial Nerve – Function: Mixed (sensory and motor)

•  Sensory: sensations from the face / taste •  Motor: controls muscles of the face

– Origin: •  Sensory: taste buds •  Motor: pons

– Foramen: internal acoustic meatus – Destination:

•  Sensory: pons •  Motor: muscles of the face

Origin and branches of the facial nerve

Posterior auricular branch

Stylomastoid foramen

Chorda tympani nerve (with mandibular branch of N V)

Lingual branch (with lingual nerve of N V)


Pons


Greater petrosal nerve

Geniculate ganglion

FACIAL NERVE (N VII)

Temporal branch

Zygomatic branches

Buccal branch

Mandibular branch

Cervical branch

The Cranial Nerves

• CN VIII: The Vestibulocochlear Nerve – Function:

•  Sensory: balance and hearing

– Origin: receptors of the vestibule and cochlea – Foramen: internal acoustic meatus – Destination: pons

Tympanic cavity

(middle ear) Semicircular

canals

Vestibular branch

(N VIII)

Facial nerve

(N VII), cut

Internal acoustic canal

VESTIBULOCOCHLEAR NERVE (N VIII)

Pons

N V

N VI N VII

N IX N XII N X

N XI

Medulla oblongata

Cochlear branch (N VIII)

Cochlea Auditory tube

Tympanic membrane

The Cranial Nerves

• CN IX: The Glossopharyngeal Nerve – Function: Mixed (sensory and motor)

•  Sensory function: tongue pain •  Motor function: swallowing

– Origin: •  Sensory: posterior 1/3 of the tongue •  Motor: salivary gland

The Cranial Nerves

• CN IX: The Glossopharyngeal Nerve (continued)

– Foramen: jugular foramen – Destination:

•  Sensory: pons •  Visceral motor: parotid salivary gland •  Somatic motor: pharyngeal muscles for swallowing

Common carotid artery

Carotid sinus

Carotid body

Lingual branch

Otic ganglion

Inferior (petrosal) ganglion

GLOSSOPHARYNGEAL NERVE (N IX)

Superior (jugular) ganglion

Pharyngeal branches

Carotid sinus branch

Parotid salivary gland

Medulla oblongata

Pons

N VII

N VI

N V

N VIII

The Cranial Nerves

• CN X: The Vagus Nerve – Function:

•  Sensory: information from organs •  Motor: sends information to the organs

– Origin: •  Sensory: from the organs •  Motor: medulla oblongata

The Cranial Nerves

• CN X: The Vagus Nerve (continued) – Foramen: jugular foramen – Destination:

•  Sensory: autonomic centers of the medulla oblongata •  Somatic motor: muscles of the palate and pharynx •  Visceral motor: respiratory, cardiovascular, and

digestive organs

Superior pharyngeal

branch

Superior laryngeal nerve

Recurrent laryngeal nerve

Internal branch

External branch

VAGUS NERVE (N X)

Inferior ganglion of vagus nerve

Cardiac branches

Cardiac plexus

Anterior vagal trunk

Left lung Right lung

Liver

Stomach

Colon

Pancreas

Spleen

Small intestine

Celiac plexus

Hypogastric plexus

Medulla oblongata

Auricular branch to external ear

Superior ganglion of vagus nerve

Pharyngeal branch

Superior laryngeal nerve

The Cranial Nerves

• CN XI: The Accessory Nerve – Function:

•  Motor: controls the sternocleidomastoid, trapezius, palate, pharynx, and larynx muscles

– Origin: spinal cord and medulla oblongata – Foramen: jugular foramen – Destination:

•  Internal branch: muscles of the palate, pharynx, and larynx

•  External branch: sternocleidomastoid and trapezius muscles

HYPOGLOSSAL NERVE (N XII)

ACCESSORY NERVE (N XI)

Internal branch: to palatal, pharyngeal, and laryngeal muscles with vagus nerve

Intrinsic muscles of tongue

Styloglossus muscle

Genioglossus muscle

Geniohyoid muscle Hyoglossus muscle

Hyoid bone

Thyrohyoid muscle

Sternohyoid muscle

Sternothyroid muscle

Omohyoid muscle

Sternocleidomastoid muscle

Trapezius muscle

Ansa cervicalis (cervical plexus)

Spinal cord

External branch of N XI

Spinal root of N XI

Cranial root of N XI


Medulla oblongata

The Cranial Nerves

• CN XII: The Hypoglossal Nerve – Function:

•  Motor: controls tongue movement

– Origin: medulla oblongata – Foramen: hypoglossal canal – Destination: tongue muscles

HYPOGLOSSAL NERVE (N XII)

ACCESSORY NERVE (N XI)

Internal branch: to palatal, pharyngeal, and laryngeal muscles with vagus nerve

Intrinsic muscles of tongue

Styloglossus muscle

Genioglossus muscle

Geniohyoid muscle Hyoglossus muscle

Hyoid bone

Thyrohyoid muscle

Sternohyoid muscle

Sternothyroid muscle

Omohyoid muscle

Sternocleidomastoid muscle

Trapezius muscle

Ansa cervicalis (cervical plexus)

Spinal cord

External branch of N XI

Spinal root of N XI

Cranial root of N XI


Medulla oblongata

CRANIAL NERVES Oh, Once One Takes The Anatomy Final, Very Good Vacations Are Heavenly! Some Say Marry Money, But My Brother Says Big Business Makes Money! (sensory/motor/both)

#

Name

SMB

From

To

I

Olfactory

S

olfactory epithelium

cerebrum

II

Optic

S

retina

thalamus

III

Occulomotor

M

eye muscles

midbrain

IV

Trochlear

M

eye muscle SO

midbrain

V

Trigeminal

B

eye + jaw area

pons

VI

Abducens

M

eye muscle LR

pons

VII

Facial

B

motor + sensory of face area

pons

VIII

Vestibulocochlear (Acoustic)

S

inner ear

pons + medulla oblongata

IX

Glossopharyngeal

B

tongue + pharynx

medulla oblongata

X

Vagus

B

visceral organs

medulla oblongata

XI

Accessory (Spinal Acc.)

M

pharynx + neck muscles

medulla oblongata + spinal cord

XII

Hypoglossal

M

tongue muscles

medulla oblongata

lecture 2: fossil record...autonomic nervous system (ans) • outside of our conscious awareness •...

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