1. frontal plane
2. transverse plane
3. sagittal plane

• Posterior - cranial cavity: brain                                                            - spinal cavity: spinal cord

• Anterior - thoracic                                                                                - abdominopelvic

• right and left pleural cavities (surrounds lungs)
• pericardial cavity (surrounds heart)
• mediastinal (space b/n apex of lungs; contains trachea, esophagus, & major vessels)

• peritoneal (stomach, intestines, spleen, liver, etc)
• peritoneal cavity includes the abdominal cavity (digestive glands & organs) and the pelvic cavity (urinary bladder, reproductive organs, digestive tract) 

• supporting cells
• protect the neuron

• by far most common or typical structure
• includes interneurons & motor neurons 

• peripheral somatic sensory neurons such as from skin & muscles in limbs 
• sensory unipolar carry impulses from receptors (like pain) to CNS (brain or spinal cord) 

• sensory
• motor
• interneuron (only located in CNS, both sensory & motor)

• afferent
• sends info from PNS (picks up from receptors) to CNS 
• somatic sensory & visceral sensory 

• efferent
• carries info from CNS to effectors of the periphery (like muscle to bring about movement or gland to bring about secretion) 

• situated b/n sensory & motor neurons; only in CNS (run up and down)
• analyze sensory input & coordinate motor outputs
• can be excitatory or inhibitory 

• most have single axon originating from special region of cell body called axon hillock 
• axons transmit electrical signals called action potentials from soma toward axon terminal
• when APs reach axon terminal, cause neurotransmitter release
• axons often branch sparsely forming collaterals
• each axon or collateral branches into 10,000 or more terminals ending in synaptic knobs that contain synaptic vesicles (membranous bags of NTs)

• dendrite of another neuron
• soma of another neuron
• axon of another neuron
• muscle (neuromuscular junction; autonomous)
• gland (sympathetic & parasympathetic)

• provide framework for neural tissue
• maintain intercellular environment
• act as phagocytes
• over 100 billion (roughly 5x number of neurons)
• aka glial cells
• have ability to reproduce

• astrocytes
• oligodendrocytes
• microglia 
• ependymal cells 

• satellite cells
• Schwann cells 

• maintain blood-brain barrier
• provide structural support
• regulate ion, nutrient,  & dissolved-gas concentrations (control chemical content of interstitial environment)
• absorb & recycle neurotransmitters
• form scar tissue after injury
• large number of cytoplasmic processes
• isolate neurons from general circulation 
• most abundant CNS neuroglia 

• myelinate CNS axons (cytoplasmic extensions tie axons together in sheath of myelin)
• provide structural framework
• cytoplasmic extensions contact somas or axons

• remove cell debris, wastes, & pathogens by phagocytosis
• smallest cells 
• defensive cells in CNS

• line ventricles (brain) & central canal (spinal cord)             -continuous and communicate, filled with CSF
• assist in producing, circulating, & monitoring cerebrospinal fluid (CSF)
• in contact with nerve tissue & contribute to secretion of constantly circulating fluid (line CSF-filled cavities)

• surround neuron cell bodies in ganglia
• regulate O₂, CO₂, nutrient, & neurotransmitter levels around neurons in ganglia (regulate exchange of material b/n cell body & environment) 

• surround all axons in PNS
• responsible for myelination of peripheral axons
• participate in repair process after injury 
• aka neurolemmocytes 

1. capillary
2. neuron
3. astrocyte

1. myelin sheath
2. process of oligodendrocyte
3. nerve fibers

1. neuron
2. microglial cell

1. satellite cells
2. cell body of neuron
3. Schwann cells (forming myelin sheath)
4. nerve fiber

• oligodendrocytes have processes that form myelin sheaths around CNS nerve fibers
• Schwann cells only contribute to one axon 
• Schwann cells wrap entirely around (even nuclei) while oligodendrocytes do not

• bundles of neurons forming discrete white flat or circular threads visible to naked eye in periphery or PNS
• usually large visible nerves contain both sensory & motor fibers w/n nerve 

• comparable structure to nerves except run w/n CNS
• composed of bundles of axons of interneurons

• go in all directions since they can be a mix of sensory & motor nerves 

• tracts are usually either ascending or descending because they are either sensory or motor
• all fibers w/n are carrying action potential impulses in the same direction 

• sensory
• deliver information to the brain

• motor
• deliver information to the periphery 

• deliver fine-touch, vibration, pressure, & proprioception info to the primary sensory cortex of the cerebral hemisphere on the opposite side of the body
• crossover occurs in the medulla after a synapse in the nucleus gracilis or nucleus cuneatus 

• somatic nervous system (SNS)
• autonomic nervous system (ANS)

• directs contraction of skeletal muscles
• corticospinal or pyramidal tracts (if something starts in the cortex it is implied that you have control over it) 

• directs the activity of glands, smooth muscle, and cardiac muscle
• subconscious motor tracts 

In the SNS, an upper motor neuron in the CNS controls a

lower-motor neuron in the brain stem/spinal cord. The axon of the lower-motor neuron has direct control over skeletal muscle fibers. Stimulation of the lower- motor neuron always has an excitatory effect on the skeletal muscle fibers

In the ANS, the axon of a preganglionic neuron in the CNS controls ______________ in the periphery. Stimulation of

the ganglionic neurons may lead to _________ or _________ of the visceral effector innervated.

• Epineurium - outer layer that becomes continuous with dura mater
• Perineurium - layer surrounding a fascicle
• Endoneurium - layer surrounding a single axon 

Which of the following divisions of the nervous system

carries motor commands to muscles and glands?

1. the afferent division of the central nervous system

2. the afferent division of the peripheral nervous system

3. the efferent division of the central nervous system

4. the efferent division of the peripheral nervous system

Which of the following structures provide pressure,

pain, and temperature sensations?

1. special sensory receptors

2. visceral sensory receptors

3. sympathetic division of the autonomic nervous system

4. somatic sensory receptors

Sensory neurons of the peripheral nervous

system, which may be myelinated, are usually:

1. multipolar.
2. anaxonic.
3. pseudounipolar.
4. bipolar.

Which of the following is a function of

astrocytes?

1. They perform repairs in damaged neural tissue and contribute to the selective permeability of CNS vasculature.

2. They are phagocytic cells of the CNS, which engulf cellular debris, waste products, and pathogens.

3. They produce myelin, which wraps around axons and functions as an insulator.

4. They are cuboidal cells, which participate in the secretion of cerebrospinal fluid within the ventricles

A synapse between neurons may involve a

synaptic terminal and which of the following

structures?

1. dendrite

2. an axon

3. a cell body

4. all of the above

• medulla oblongata
• pons
• cerebellum
• midbrain (mesencephalon)
• diencephalon
• cerebrum (telencephalon)

• conscious thought processes & intellectual functions
• memory storage & processing 
• conscious/subconscious regulation of skeletal muscle contractions

*only conscious portion of the brain*

• thalamus
• hypothalamus
• epithalamus

• relay & processing centers for sensory information
• relays info to cerebrum 

• centers controlling emotions
• autonomic functions
• hormone production
• thirst, limbic system, & temperature regulation
• some habitual activity

• contains pineal gland

• mesencephalon/midbrain
• pons
• medulla oblongata

• processing of visual & auditory data
• generation of reflexive somatic motor responses
• maintenance of consciousness & alertness

• relays sensory info to cerebellum & thalamus
• subconscious somatic & visceral motor centers

• relays sensory info to thalamus & to other portions of the brain stem
• autonomic centers for regulation of visceral function (cardiovascular, respiratory, & digestive system activities)

• coordinates complex somatic motor patterns
• adjusts output of other somatic motor centers in brain & spinal cord (results in smooth operation)
• balance, coordination, posture; key role in fine movements

1. cerebrum
2. diencephalon
3. thalamus
4. hypothalamus
5. mesencephalon
6. pons
7. medulla oblongata
8. cerebellum
9. fissures
10. sulci
11. gyri

• inner accummulation of gray matter (basal)
• surrounded by tracts of white matter
• outer region of gray matter (cerebral cortex)

• Ventricles 1 & 2 (lateral ventricles): in cerebral hemispheres & communicate w/ third ventricle through interventricular foramen
• third ventricle: in diencephalon
• fourth ventricle: lies b/n pons & cerebellum & continues in spinal cord as central canal 

aqueduct communicates w/ 3rd & 4th ventricles

1. anterior horns of lateral ventricles
2. pons
3. medulla oblongata
4. cerebellum
5. fourth ventricle
6. inferior horns of lateral ventricles
7. posterior horns of lateral ventricles
8. third ventricle
9. lateral ventricles 

• bones of the skull (parietal, frontal, occipital, & temporal)
• cranial meninges (dura mater, arachnoid mater, & pia mater)
• cerebrospinal fluid
• blood-brain barrier

• outer endosteal layer (closer to bone): layer felt w/n anterior fontanel (bregma) in an infant
• inner meningeal layer (closer to brain): space b/n 2 layers forms dural sinuses 

• falx cerebri
• tentorium cerebelli - roof of cerebellum
• falx cerebelli - separates both hemispheres of cerebellum
• diaphragma sellae

anchorage & support for brain structures

• meningeal layer that extends into longitudinal fissure
• inferior/anterior portion attaches tp crista galli
• inferior/posterior portion attaches to internal occipital crest & tentorium cerebelli 

• separates the cerebellular hemispheres from the cerebral hemispheres
• extends across the cranium at right angles to the falx cerebri

• extends from the tentorium cerebelli to separate the cerebellar hemispheres 

• lines the sella turcica of sphenoid bone
• it anchors the dura mater to sphenoid bone
• it encases the pituitary gland (hypophysis) 

• projections of the arachnoid mater
• CSF flows through these to enter into blood circulation (through superior sagittal sinus)

• the collagenous fibers help anchor cerebral blood vessels 

• attached to the surface of the brain (cannot be separated)
• very delicate structure firmly attached nerve tissue
• follows sulci & gyri of brain
• helps to anchor larger blood vessels of cerebrum 

• provides protection of the brain & spinal cord
• provides support
• transports nutrients to CNS tissue
• transports waste away from CNS 

• produced in brain ventricles by the ependymal cells of choroid plexus
• circulates from ventricles to subarachnoid space & then to superior sagittal sinus (arachnoid granulations) to enter systemic circulation 

• the ependymal cells are selective barrier, actively transporting nutrients, vitamins, & ions into CSF
• cells also actively remove ions or compounds from CSF to stabilize its composition 

1. superior sagittal sinus
2. arachnoid granulation
3. falx cerebri
4. subarachnoid space
5. pia mater
6. dura mater

• restricts the type of substances that can pass from the blood to the CNS (lipids by diffusion & hydrophilic through specific transport systems)
• protects brain from many hormones & circulating chemicals 

• cardiovascular centers (cardiac & vasomotor)
• respiratory centers (rhythmic breathing)

1. descending tracts
2. ascending tracts
3. medulla oblongata
4. reticular formation
5. fourth ventricle
6. cerebellum

• Responsible for processing auditory and visual stimuli
• Auditory processing occurs in the inferior colliculus
• Visual processing occurs in the superior colliculus

• forms roof of third ventricle
• contains pineal gland

• produces the hormone melatonin
• regulates our day/night cycles

• Forms the walls of the third ventricle
• There is a right and a left thalamus
• Thalamic nuclei are egg-shaped

thalamus relays info to cerebrum & processes sensory info

• the hypothalamus & the choroid plexus where CSF is secreted
• the hypothalamus has to be able to sense different types of blood composition & be able to insert various components into the blood 

• Forms the floor of the third ventricle
• controls different autonomic functions (heart rate, blood pressure, temp.)
• also involved in emotions, thirst, some "habitual" activity

• Folia (folds similar to gyri of the cerebrum)
• Anterior and posterior lobes
• Flocculonodular lobes
• Arbor vitae
• Cerebellar peduncles

• frontal
• parietal
• occipital
• temporal

• protuberances - gyri
• indentations - sulci

• Central sulcus: separates frontal and parietal lobes
• Lateral sulcus: define temporal lobes
• Parieto-occipital sulcus: define occipital lobe

• primary motor cortex; neurons direct voluntary movements
• located in the frontal lobe
• anterior to central gyrus

• primary sensory cortex; neurons receive somatic sensory info for touch, pressure, pain, taste, & temp.
• located in the parietal lobe
• posterior to central gyrus

• superficial cerebral cortex of gray matter
• internal white matter
• basal nuclei 

• tracts that interconnect areas of neural cortex within a hemisphere 
• examples: arcuate fibers and longitudinal fasciculi

• tracts that connect the two hemispheres 
• examples: anterior commissure and corpus callosum

• tracts that link the cerebrum with other regions of the brain and spinal cord
• example: corticospinal tracts

• includes several functionally & anatomically interconnected structures from diencephalon & cerebrum
• establishes emotional states (behavior)
• links conscious functions w/ unconscious autonomic functions
• faciliates memory storage & retrieval 
• instinct & reaction

• Thalamus
• Hypothalamus
• Cingulate gyrus
• Amygdala
• Hippocampus
• Basal Ganglia

Which of the following statements regarding cerebrospinal fluid (CSF) is true?

1. The microglial cells secrete CSF into the ventricles.

2. The ependymal lining is freely permeable throughout the entire CNS

3. Although CSF is derived from plasma, it is not merely a simple filtrate of blood.

3.

ependymal cells secrete CSF; ependymal lining not freely permeable throughout entire CSF b/c choroid plexus has tight junctions

The cerebral cortex is linked to the diencephalon, brain stem, cerebellum, and spinal cord through which of the following

structures?

1. association fibers

2. projection fibers

3. commissural fibers

4. longitudinal fasciculi

In which lobe of the cerebrum is the primary motor cortex?

1. frontal lobe

2. parietal lobe

3. temporal lobe

4. occipital lobe

Which of the following statements regarding the postcentral gyrus are true? (Select 2)

1. It is found in the frontal lobe.
2. It is found in the parietal lobe.
3. Its surface contains the primary motor cortex.
4. Its surface contains the primary sensory cortex.

2. It is found in the parietal lobe.

4. Its surface contains the primary sensory cortex.

Which of the following functional deficits may occur in an individual with a damaged visual association area?

a. Letters appear extremely blurry, but the person can read with corrective lenses.

b. Written letters and words can be understood, but the person cannot read.

c. An individual can scan the lines of a printed page, and see rows of clear symbols that convey no meaning.

d. The eyes cannot follow the lines on a printed page.

Which thalamic structure(s) projects visual information to the visual cortex of the occipital lobe?

1. corpus callosum
2. lateral geniculate nuclei
3. ventral posterior nuclei
4. basal ganglia

Which of the following statements regarding the epithalamus is true?

a. It is the site of concentration of most of the neural tissue in the diencephalon.

b. The interthalamic adhesion (massa intermedia) extends into the third ventricle from the epithalamus on either side.

c. The posterior portion of the epithalamus contains the pineal gland, an endocrine structure that secretes melatonin.

d. It controls heart rate and blood pressure via regulation of autonomic centers in the medulla oblongata.

Which of the following is a function of the mesencephalon (or midbrain)?

a. It is responsible for the conscious control of skeletal muscles.

b. It modifies the output of respiratory centers in the medulla oblongata.

c. It contains centers involved with emotions and visceral processes, and controls autonomic function.

d. It processes visual and auditory information and generates reflexive responses to these stimuli (corpora quadrigemina).

oculomotor (III), facial (VII),  glossopharyngeal (IX), &

vagus (X)

• nerves innervate the periphery emerging from brain (CN XI has cranial & spinal roots)
• can be visualized on ventrolateral surface of brain
• numbered from 1 to XII beginning at anterior aspect of brain (olfactory I)

1. olfactory bulb (termination of CN I)
2. olfactory tract
3. optic chiasm
4. optic nerve (CN II)
5. oculomotor nerve (CN III)
6. trochlear nerve (CN IV)
7. trigeminal nerve (CN V)
8. abducens nerve (CN VI)
9. facial nerve (CN VII)
10. vestibulocochlear nerve (CN VIII)
11. glossopharyngeal nerve (CN IX)
12. vagus nerve (CN X)
13. hypoglossal nerve (CN XII)
14. accessory nerve (CN XI)

• function: sensory (smell)
• origin: olfactory epithelium
• foramen: olfactory foramina (cribiform plate ethmoid bone)
• destination: olfactory bulbs

• function: special sensory; vision
• origin: retina
• foramen: optic canal (sphenoid bone)
• destination: diencephalon (from lateral geniculate nucleus in thalamus) to visual cortex (occipital lobe)

• function: controls extra-ocular eye muscles & intrinsic muscles of eye
• origin: mesencephalon (parasympathetic nucleus & somatic subnuclei)
• foramen: superior orbital fissure
• destination: extra-ocular eye muscles, ciliary body, iris sphincter

• motor function (also proprioceptive; sensory)
• superior, inferior, & medial rectus
• inferior oblique
• levator palpebrae superioris 

• function: control SO EOM (motor function, also proprioceptive; sensory)
• origin: nucleus in mesencephalon; exits midbrain from dorsal aspect
• foramen: enters orbit through superior orbital fissure
• destination: SO EOM 

What is the function, origin, foramen, & destination of the first branch of the trigeminal nerve (V₁)?

(CN V has a mixed sensory & motor function)

• function: sensations from forehead, eyelids, & nose
• origin: semilunar ganglion (sensory from 3 branches)
• foramen: exits through superior orbital fissure
• destination: pons (from semilunar sensory ganglion)

What is the function, origin, foramen, & destination of the second branch of the trigeminal nerve (V2)?

(CN V has a mixed sensory & motor function)

 MAXILLARY

• function: sensations from lower eyelid, upper lip, & cheek
• origin: semilunar ganglion (sensory from 3 branches)
• foramen: foramen rotundum
• destination: pons (from semilunar sensory ganglion)

What is the function, origin, foramen, & destination of the third branch of the trigeminal nerve (V3)?

(CN V has a mixed sensory & motor function)

• function: sensory & motor (muscles of mastication)
• origin: motor nucleus in pons (for motor branch in mandibular)
• foramen: foramen ovale
• destination: mandibular muscles

• function: abducts eye (move away from midline); motor function (proprioceptive; sensory)
• origin: motor nucleus in pons (exits brain stem b/n pons & medulla)
• foramen: superior orbital fissure
• destination: innervates LR EOM

• function: sensory - sensations from face/taste anterior 2/3rds of tongue.
• origin: sensory - taste buds > geniculate ganglion > nucleus solitarious (pons) > thalamus > cerebral cortex (temporal lobe)
• foramen: internal acoustic meatus (together w/ CN VIII); exits cranium through stylomastoid foramen
• destination: sp. sensory - (taste); pons (n. solitarious).

• function: motor - controls muscles of facial expression...parasymp. fibers - lacrimal gland & others
• origin: motor - nucleus in pons
• foramen:  internal acoustic meatus (together w/ CN VIII); exits cranium through stylomastoid foramen
• destination: motor - muscles of facial expression...motor visceral - lacrimal gland (pteriogopalatine-ps ganglion) or sublingual & submandibular salivary glands (submandibular-ps ganglion)

• Function: Special sensory: balance (vestibular) and hearing (cochlear)
• Origin: receptors of the vestibule & cochlea in inner ear
• Foramen: internal acoustic meatus

destination: pons and medulla

• Vestibular nucleus: pons & medulla oblongata > cerebellum/CN VI nucleus/midbrain (including CN III & IV & superior colliculus) > eventually will reach cerebral cortex
• Cochlear nucleus: in medulla > sup. olivary nucleus (medulla) > inferior colliculus (midbrain) > thalamus > cerebral cortex (temporal lobe)

• Function: Mixed (sensory and motor) - Sensory function: tongue pain and taste...Carotid body & sinus -(blood pressure and gas content)
• Origin: Sensory - posterior 1/3 of the tongue...carotid body & sinus - common carotid (artery) bifurcation 
• Foramen: exits through jugular foramen (together with CNs X and XI and internal jugular vein)
• Destination: Sensory - nuclei in medulla oblongata

• function: motor function - swallowing...Visceral motor - parasympathetic
• origin: Motor - nuclei in the medulla oblongata
• foramen: exits through jugular foramen (together with CNs X and XI and internal jugular vein)
• destination: Visceral motor: parotid salivary gland (otic-parasympathetic-ganglion)...Somatic motor - pharyngeal muscles for swallowing

• function: visceral sensory- info from organs & from different regions in head and neck (including taste)
• origin: sensory- from most organs in thoracic & abdominal cavities, tongue, pharynx
• foramen: exits the skull through jugular foramen
• destination: visceral sensory - autonomic centers of the medulla oblongata

• function: motor visceral (ps) - sends info to organs (respiration, cardiovascular, digestive, excretory)...somatic motor - to pharynx and palate (deglutition)
• origin: motor - nucleus in medulla oblongata
• foramen: exits the skull through jugular foramen
• destination: somatic motor - muscles of palate & pharynx...visceral motor - respiratory, cardiovascular, & digestive organs

• function: motor - controls the sternocleidomastoid, trapezius, palate, pharynx, & larynx muscles
• origin: spinal cord & medulla oblongata (internal)
• foramen: exits through jugular foramen
• destination: internal branch - muscles of palate, pharynx, & larynx...external branch - sternocleidomastoid & trapezius

• function: motor - controls tongue movement
• origin: motor nucleus in medulla oblongata
• foramen: exits skull through hypoglossal canal
• destination: tongue muscles

• sensory: I, II, and VIII
• motor: III, IV, VI, XI, and XII
• mixed: V, VII, and IX

1. ciliary ganglion
2. submandibular ganglion
3. pterygopalatine ganglion
4. otic ganglion
5. semilunar ganglion

• make up the CNS
• both integrate & process information
• can function w/ each other or independently

• 45 cm in length
• passes through foramen magnum
• extends from end of medulla oblongata to first lumbar vertebra (L₁)

1. cervical region
2. thoracic region
3. lumbar region
4. sacral region
5. coccygeal region 

• cervical enlargement
• lumbosacral enlargement
• conus medullaris 
• filum terminale
• posterior median sulcus & anterior median fissure

1. dorsal root
2. dorsal root ganglion
3. central canal
4. spinal nerve
5. ventral root
6. gray matter
7. white matter

C₃

1. conus medullaris of spinal cord
2. cauda equina
3. sacrum
4. filum terminale

• White matter
• Gray matter
• Central canal
• Dorsal root & ventral root - merge to form a spinal nerve

• sensory
• axons extend from the neuron cell body located in the dorsal root ganglion

• composed of motor axons that extend from nuclei located in the (spinal) ventral & lateral horns

Sensory components (afferent fibers from dorsal roots)

• Transmit impulses toward the spinal cord

Motor components (efferent fibers from ventral roots)

• Transmit impulses from spinal cord to periphery (muscles, blood vessels and glands)

• continuous with cranial (cerebral) meninges
• help anchor the spinal cord in position
• made of three layers

• Dura mater: tough, fibrous outermost layer
• Arachnoid mater: middle layer
• Pia mater: innermost layer

1. loose CT & periosteum of cranium
2. epicranial aponeurosis
3. scalp
4. cerebral cortex (covered by pia mater)
5. arachnoid mater
6. subarachnoid space
7. dura mater
8. cranium

• central canal
• consists of somas (cell bodies) surrounding the central canal

• located outside the gray matter area
• consists of axons
• nerves are organized into tracts or columns

• posterior (dorsal) gray horns: somatic sensory & visceral nuclei
• lateral gray horns: visceral motor nuclei
• anterior (ventral) gray horns: somatic motor nuclei
• gray commissure: encloses central canal & connects gray matter on both sides of cord

• sensory tracts (ascending tracts)
• motor tracts (descending tracts) 

Damage to the dorsal root of the T1 spinal nerve will interfere with which of the following?

1. Innervation of skeletal muscles in the upper limb

2. Innervation of sweet glands upper limb

3. General sensory innervation of the upper limb

4. All the above

What is found inside a dorsal root ganglion of a spinal nerve? (Select 2 answers)

1. Astrocytes

2. Cell bodies of unipolar sensory neurons

3. Cerebrospinal fluid

4. Ependymal cells

5. Oligodendrocytes

6. Satellite cells

2. Cell bodies of unipolar sensory neuron

6. Satellite cells

31 pairs of spinal nerves

• 8 cervical
• 12 thoracic
• 5 lumbar
• 5 sacral
• 1 coccygeal

• all spinal nerves have dorsal ramus & ventral ramus
• spinal nerves from T1-L2 have four branches: dorsal ramus, ventral ramus, white ramus, & gray ramus

white ramus: sympathetic preganglionic & myelinated fiber that leaves the spinal nerve & enters paravertebral sympathetic ganglionic chain

gray ramus: sympathetic postganglionic & unmyelinated fiber that returns to the spinal nerve from the sympathetic ganglion

• postganglionic fibers: has capability to do something
• preganglionic fibers: must make synapse in ganglion; can't secrete, contract, etc. 

the dorsal ramus

• supplies back; mixed (note: sensory dorsal roots)
• sensory innervation from afferent & motor innervation to efferent regions in neck and back

the ventral ramus

• supplies ventral aspects of body; mixed (note: motor ventral roots)
• sensory innervation from & motor commands to regions in ventrolateral body surface, body wall, & limbs

• spinal nerves T1-L2
• white and gray ramus are collectively called rami communicantes
• contain motor sympathetic fibers to innervate smooth muscles & glands in limbs & body walls
• sympathetic innervation to viscera in body cavities will be through splanchnic nerves 

somatic motor > ventral root > spinal nerve > white ramus ...

(a) preganglionic fiber to sympathetic ganglia innervating abdominopelvic viscera

(b) sympathetic ganglion > ...

(1) postganglionic fibers to smooth muscles, glands, visceral organs in thoracic cavity

(2) gray ramus to postganglionic fibers to smooth muscles, glands, etc. of back or body wall & limbs

visceral motor > ventral root > spinal nerve > ...

(a) ventral ramus > to skeletal muscles of body wall & limbs

(b) dorsal ramus > to skeletal muscles of back

(a) from interoceptors of visceral organs > rami communicantes > dorsal root ganglion > dorsal root > somatic sensory

(b) from interoceptors of body wall, limbs > ventral ramus > dorsal root ganglion > dorsal root > somatic sensory

(c) from interoceptors of back > dorsal ramus > dorsal root ganglion > dorsal > somatic sensory

(a) from exteroceptors, peoprioceptors of boday wall, limbs > ventral ramus > dorsal root ganglion > dorsal root > somatic sensory

(b) from exteroceptors, proprioceptors of back > dorsal ramus > dorsal root ganglion > dorsal root > somatic sensory 

• Dorsal root ganglia contain the cell bodies of (unipolar) somatic & visceral sensory neurons
• axons from these sensory neurons enter the cord to: 

(a) synapse in sensory nuclei present in gray matter of spine

(b) enter afferent spinal tracts (white matter) to reach brain  

• basis for referred pain
• herpes zoster manifestation
• loss of sensation associated to nerve injury or anesthesia during surgery

• dorsal horns: sensory neurons
• lateral horns: visceromotor - thoracolumbar (sympathetic) or sacral (parasympathetic)
• ventral horns: somatic motor

• dorsal roots - sensory (somatic & visceral) afferent information
• dorsal rami (of spinal nerve) - sensory & motor to the posterior aspects of the body

• ventral roots: motor (somatic & visceral) efferent commands
• ventral rami (of spinal nerve): sensory & motor to the anterior aspects of the body

1. cervical plexus
2. brachial plexus
3. lumbar plexus
4. sacal plexus 

(sometimes lumbar & sacral combined to form lumbosacral plexus)

• C₁-C₅
• consists of cutaneous & muscular branches
• cutaneous branches innervate head, neck, & chest 

• Omohyoid, sternohyoid, geniohyoid, thyrohyoid
• Sternothyroid
• Scalenes
• Sternocleidomastoid
• Levator scapulae
• Trapezius
• Diaphragm (controlled by the phrenic nerve of the cervical plexus)

• cervical spinal nerves emerge from C₁-C₈
• thoracic s.n. emerge from T₁-T₁₂
• lumbar s.n. emerge from L₁-L₅
• sacral s.n. emerge from S₁-S₅
• coccygeal s.n. emerge from Co₁

1. cervical plexus
2. brachial plexus
3. lumbar plexus
4. sacral plexus

• the neural "wiring" of a single reflex
• begins at sensory receptor & ends @ peripheral receptor

1. arrival of stimulus & activation of sensory receptor
2. relay of info to CNS & activation of sensory neuron
3. information processing in CNS
4. activation of motor neuron
5. response by effector

1. development
2. response
3. complexity of circuit
4. processing site

• innate reflexes: genetically determined
• acquired reflexes: learned

• somatic reflexes: control skeletal muscle contractions & include superficial & stretch reflexes
• visceral (autonomic) reflexes: control actions of smooth & cardiac muscles & glands

• monosynaptic: one synapse
• polysynaptic: multiple synapses (two to several hundred)

• spinal reflexes: processing in the spinal cord
• cranial reflexes: processing in the brain

Which structure of the spinal cord contains somatic and visceral sensory nuclei?

1. anterior (ventral) gray horn

2. lateral white column

3. posterior (dorsal) gray horn

4. posterior white column

• regulates body temperature
• coordinates cardiovascular, respiratory, digestive, excretory, & reproductive functions

Autonomic NS

-axons innervate visceral organs, smooth muscle, & glands

-has afferent & efferent neurons

-afferent pathways originate in visceral receptors

Somatic NS

-axons innervate skeletal muscles (motor)

-has afferent & efferent neurons

-afferent pathways originate in skeletal muscles, skin, mucosal membranes, etc. 

• sympathetic division - also called thoracolumbar division; known as "fight or flight" system
• parasympathetic division - also called craniosacral division; known as "rest & repose" system 

• Thoracic and upper lumbar nerves synapse in ganglia near the spinal cord (paravertebral sympathetic ganglia/sympathetic trunk0
• sympathetic activation results in increased metabolism & alertness

• ganglia are located near the target organ
• parasympathetic activation results in energy conservation

• for both - all preganglionic fibers release acetylcholine (stimulatory effects)
• Sympathetic division - most postganglionic fibers release norepinephrine (stimulatory effects)
• Parasympathetic division - postganglionic fibers release acetylcholine (inhibitory effects)

• preganglionic neurons b/n T₁-L₂ spinal cord segments
• 2 types of ganglionic neurons near vertebral columns: sympathetic chain ganglia (bilateral to vertebral column) & collateral ganglia (anterior to vertebral column)
• specialized neurons ("modified sympathetic ganglion"); chromaffin cells in medulla of adrenal glands

• acute response: neurotransmitters acting in synapse (in sympathetic)
• chronic response: associated with same ganglia but acting as hormones 

• cell bodies are in the lateral gray horns
• axons enter ventral roots of spinal nerves (rami communicantes; white & gray)
• sympathetic chain ganglia (aka paravertebral ganglia or sympathetic trunk)
• SCG control effectors in body wall, head, neck, limbs, & thoracic cavity (heart, lungs, blood vessels) 

• Constriction of cutaneous blood vessels, reduction in circulation to skin & to most other organs in body wall
• Acceleration of blood flow to skeletal muscles & brain
• Stimulation of energy production & use by skeletal muscle tissue
• Release of stored lipids from subcutaneous adipose tissue
• Stimulation of secretion by sweat glands
• Stimulation of arrector pili
• Dilation of the pupils & focusing for distant objects

• Acceleration of heart rate & increasing the strength of cardiac contractions
• Dilation of respiratory passageways

• "prevertebral ganglia"
• neurons innervate effectors in the abdominopelvic cavity 

• modified sympathetic ganglion in the suprarenal gland
• neurons (chromaffin cells) release NTs that act like hormones (longer effect than NTs released at sympathetic synapses) 

1. preganglionic: lateral gray horns of spinal segments T1-L2 > ganglionic neurons: sympathetic chain ganglia (paired) to innervation by postganglion fibers > target organs: visceral effectors in thoracic cavity, head, body wall, & limbs
2. preganglionic: lateral gray horns of spinal segments T1-L2 > ganglionic neurons: collateral ganglia (unpaired) to innervation by postganglion fibers > target organs: visceral effectors in abdominopelvic cavity
3. preganglionic: lateral gray horns of spinal segments T1-L2 > ganglionic neurons: suprarenal medullae (paired) through release of hormones into circulation > target organs: organs & systems throughout body (medulla in adrenal gland)

1. sympathetic chain ganglia (paired)
2. collateral ganglia (unpaired)
3. suprarenal medullae (paired)
4. visceral effectors in thoracic cavity, head, body wall, & limbs
5. visceral effectors in abdominopelvic cavity
6. organs & systems throughout body

• Preganglionic neurons originate in inferior thoracic & superior lumbar segments of the spinal cord
• Fibers pass through sympathetic chain ganglia w/o synapsing
• Converge to form greater, lesser, & lumbar splanchnic nerves
• Splanchnic nerves converge & synapse on collateral ganglia. These postganglionic fibers will reach their targets in the abdominopelvic cavity

• Reduces blood supply to the skin
• Increases blood supply to skeletal muscles
• Stimulates energy production by skeletal muscles
• Increases triacylglycerol catabolism
• Stimulation of arrector pili muscles
• Dilation of pupils (mydriasis)
• Increases heart rate
• Dilation of respiratory tree (bronchodilator)

• Reduction of blood flow to the visceral organs
• Decreases activity of the digestive organs
• Stimulation of glycogen degradation in the liver
• Stimulates adipose cells to release energy reserves
• Relaxation of smooth muscles in the urinary bladder
• Cause ejaculation in males

• Preganglionic fibers in splanchnic nerves synapse in: Celiac ganglion, Superior mesenteric ganglion, & Inferior mesenteric ganglion
• Postganglionic fibers leave those ganglia to innervate target organs in abdomen/pelvis

• preganglionic fibers pass through sympathetic chain & celiac ganglion w/o synapsing
• these fibers proceed to suprarenal medulla & synpase on modified neurons that, when stimulated, will release NTs that act as hormones (epinephrine & norepinephrine) 

• release of epinephrine & norepinephrine into the general circulation 

• preganglionic neurons: in brain stem & sacral segments
• postganglionic neurons: close to or w/n target organ

• go to the intrinsic eye muscles, pupil, and lens
• ciliary ganglion

• go to the lacrimal glands, salivary glands, nasal glands
• pterygopalatine & submandibular ganglia 

• go to the parotid salivary glands
• otic ganglion

• go to the visceral organs of the thoracic cavity & abdominal cavity; visceral organs of neck
• intramural ganglia

• leave via the pelvic nerves
• go to visceral organs in the inferior portion of the abdominopelvic cavity
• intramural ganglia

1. ciliary ganglion
2. pterygopalatine & submandibular ganglia
3. otic ganglion
4. intramural ganglia
5. intramural ganglia
6. intrinsic eye muscles (pupil & lens shape)
7. nasal, tear, & salivary glands
8. parotid salivary gland
9. visceral organs of neck, thoracic & abdom. cavities
10. visceral organs in inferior portion of abdominopelvic cavity

List 9 functions of the parasympathetic division:

• pupil constriction & lens accommodation
• inc. smooth muscle activity for digestive system
• secretion of digestive enzymes for digestive glands
• reduced heart rate
• increase lacrimal & salivary gland secretion
• contraction of urinary bladder
• stimulation & coordination of defecation
• constriction of respiratory passages
• sexual arousal 

• most vital organs are innervated by both symp.& parasym. nerves
• two often oppose or are "complementary" of each other

sympathetic; apply viscera & do not synapse in chain

Which of the following systems have both afferent & efferent neurons?

1. ANS only
2. SNS only
3. both ANS and SNS
4. neither ANS nor SNS

1. both ANS and SNS

True or False:

The axons of a visceral motor neuron in the CNS synapses w/ a second neuron located in a peripheral ganglion. 

True or False:

All postganglionic autonomic fibers release acetylcholine (ACh), whose effects are always stimulatory.

FALSE.

sympathetic postganglionic releases NE (which is also stimulatory)

1. sympathetic
2. parasympathetic

Which accurately describes collateral (celiac) ganglion?

1. They lie posterior to the vertebral column.
2. They contain neurons that innervate visceral effectors in the body wall & thoracic cavity.
3. They are paired structures that lie anterior to the verteral column.
4. They innervate visceral effectors in the abdominopelvic cavity.

1. They innervate visceral effectors in the abdominopelvic cavity.

Which is an effect produced by symp. postganglionic fibers in spinal nerves?

1. release of stored lipids from subcutaneous adipose tissue
2. decreased heart rate
3. reduction of pupillary diameter & focusing for close obj.
4. release of epinephrine & NE into general circulation

1. release of stored lipids from subcutaneous adipose tissue

Which pairing of parasympathetic ganglia & target organs is correct?

1. pterygopalatine ganglia; sweat glands
2. pelvic nerves intramural ganglia; visceral organs of neck & thoracic cavity
3. otic ganglion; visceral organs in inferior portion of abdominopelvic cavity
4. otic ganglion; parotid salivary gland

1. otic ganglion; parotid salivary gland

Which of the following are functions of the parasympathetic division of the ANS? (Select two)

1. lens accommodation
2. dilation of pupils (mydriasis)
3. reduction of heart rate & force of contraction
4. bronchodilation

1. lens accommodationm                                         3.reduction of heart rate & force of contraction