A&P Exam 3 (extra help)

Spinal reflex arc pathway

Receptor, sensory (afferent) neuron, integration center (processes signal), motor (efferent) neuron, effector organ

Frontal lobe

Motor, gustation, Broca’s area (speech)

Parietal lobe

Body sensations (primary somatosensory cortex)

Temporal lobe

Hearing, olfactory, Wernicke’s area (language comprehension)

Occipital lobe

Vision

Cranial Nerve I

Olfactory

Sensory

Smell

Cranial Nerve II

Optic

Sensory

Vision

Cranial Nerve III

Oculomotor

Motor

Eye movements

Cranial Nerve IV

Trochlear

Motor

Eye movements

Cranial Nerve V

Trigeminal

Both

Sensory: Facial sensations

Motor: Chewing

Cranial Nerve VI

Abducens

Motor

Eye movement

Cranial Nerve VII

Facial

Both

Sensory: Taste, face sensations

Motor: Facial expressions

Cranial Nerve VIII

Vestibulocochlear

Sensory

Balance & hearing

Cranial Nerve IX

Glossopharyngeal

Both

Sensory: Taste

Motor: Swallowing, speech, saliva

Cranial Nerve X

Vagus

Both

Sensory: Autonomic sensations; monitors BP & breathing
Motor: Visceral smooth muscle

Cranial Nerve XI

Accessory

Motor

Head & neck movements

Cranial Nerve XII

Hypoglossal

Motor

Tongue (speech & swallowing)

What are the two main divisions of the PNS?

• Sensory (afferent) division

• Motor (efferent) division

PNS sensory division?

• Carries information toward the CNS

• Somatic sensory: from skin, skeletal muscles, and joints

• Visceral sensory: from internal organs

PNS motor division?

• Carries commands away from the CNS

• Somatic motor: controls skeletal muscles

• Autonomic motor: controls smooth muscle, cardiac muscle, and glands

What are the two divisions of the autonomic nervous system?

• Sympathetic: fight or flight

• Parasympathetic: rest and digest

Na⁺ in

Depolarization

K+ out

repolarization and the usual cause of hyperpolarization

Depolarization

• Voltage rises

• Voltage-gated Na⁺ channels open, and Na⁺ moves into the cell. The inside becomes less negative and may become positive.

Repolarization

• Voltage falls

• Na⁺ channels inactivate, and voltage-gated K⁺ channels allow K⁺ to move out. The inside becomes negative again.

Hyperpolarization

• Dips below rest

• K⁺ channels close gradually, so extra K⁺ leaves. The membrane becomes briefly more negative than its resting level before returning to rest

What is a synapse?

The communication junction between a neuron and another cell.

What are the 3 main parts of a chemical synapse?

• Presynaptic: sending cell; releases neurotransmitters.

• Synaptic cleft: gap neurotransmitters cross.

• Postsynaptic: receiving cell; has receptors.

What is an excitatory postsynaptic potential (EPSP)?

A change in the receiving cell that makes it more likely to produce an action potential.

What is an inhibitory postsynaptic potential (IPSP)?

A change in the receiving cell that makes it less likely to produce an action potential.

Where is a preganglionic neuron's cell body located?

In the CNS (brainstem or spinal cord). Its axon travels to an autonomic ganglion.

Where are preganglionic neurons located?

In the spinal cord from T12-L2 (thoracolumbar division)

Sympathetic trunk ganglia

lie in 2 vertical rows from C1-S3, supply organs mostly above the diaphragm

Prevertebral ganglia

lie anterior to vertebral column and innervate organs mostly below diaphragm

What are the structures of the PNS (peripheral nervous system)?

Cranial nerves (12 pairs) and spinal nerves (31 pairs)

Circumvallate papillae

largest, form V-shaped row at the back of the tongue, 100-300 taste buds, bitter & umami tastes

Fungiform papillae

mushroom-shaped, over entire surface, 5 taste buds each, has sweet salty umami tastes

Foliate papillae

small trenches on lateral margins, degenerate early childhood, sour & bitter tastes

Filiform papillae

most numerous, entire surface of tongue, contain tactile receptors, no taste buds

Conus medullaris

spinal cord terminates here (approx. L1/2)

Filum terminale

fibrous tissue that attaches to the coccyx and anchors the spinal cord/meninges at the bottom

Axon terminal

branches have knobs containing synaptic vesicles (secretary area)