Integrated Pathways (Full System Tracing)

Stimulus (Withdrawal Reflex)

Painful stimulus activates nociceptors in the finger skin

Sensory Relay (Withdrawal Reflex)

Signal travels along a first-order somatic sensory neuron

Cell Body Location (Withdrawal Reflex)

Located in the dorsal root ganglion

Entrance to CNS (Withdrawal Reflex)

Sensory axon enters through the dorsal root

Synapse 1 (Withdrawal Reflex)

Sensory neuron synapses with interneuron in posterior gray horn

Classification (Withdrawal Reflex)

Polysynaptic reflex involving interneurons

Synapse 2 (Withdrawal Reflex)

Interneuron synapses with lower somatic motor neuron

Motor Soma Location (Withdrawal Reflex)

Located in anterior gray horn

Exit from CNS (Withdrawal Reflex)

Signal exits through ventral root

Peripheral Path (Withdrawal Reflex)

Travels through ventral ramus to limb

Effector (Withdrawal Reflex)

Skeletal muscle (flexors)

Response (Withdrawal Reflex)

ACh released → muscle contracts → hand withdraws

Stimulus (Micturition Reflex)

Bladder wall stretch (distention)

Receptor (Micturition Reflex)

Stretch receptors in bladder wall

Classification (Micturition Reflex)

Long visceral reflex

Integration Center (Micturition Reflex)

Sacral spinal cord segments S2–S4

Preganglionic Activation (Micturition Reflex)

Parasympathetic preganglionic neurons activated

Exit Path (Micturition Reflex)

Pelvic nerves carry signal

Synapse Location (Micturition Reflex)

Intramural ganglia in bladder wall

Ganglion Neurotransmitter (Micturition Reflex)

ACh released onto nicotinic receptors

Postganglionic Fiber (Micturition Reflex)

Short unmyelinated fiber to effector

Effector Neurotransmitter (Micturition Reflex)

ACh released onto muscarinic receptors

Response Detrusor (Micturition Reflex)

Bladder smooth muscle contracts

Response Sphincter (Micturition Reflex)

Internal urethral sphincter relaxes

Receptor (Gustatory Pathway)

Chemoreceptors (taste buds) detect dissolved sweet molecules

Anterior Relay (Gustatory Pathway)

Facial nerve (CN VII) carries signal from anterior 2/3 of tongue

Posterior Relay (Gustatory Pathway)

Glossopharyngeal nerve (CN IX) carries signal from posterior 1/3

Medulla Processing (Gustatory Pathway)

Synapse in solitary nucleus

Thalamic Relay (Gustatory Pathway)

Signal sent to ventral nuclei of thalamus

Cerebral Destination (Gustatory Pathway)

Gustatory cortex in insula

Receptor (Auditory Pathway)

Hair cells in cochlea detect sound vibrations

Relay (Auditory Pathway)

Signal travels via vestibulocochlear nerve (CN VIII)

Midbrain Processing (Auditory Pathway)

Inferior colliculi process signals

Reflexive Action (Auditory Pathway)

Tectospinal tract triggers head turn

Thalamic Relay (Auditory Pathway)

Medial geniculate nucleus processes signal

Cerebral Destination (Auditory Pathway)

Primary auditory cortex in temporal lobe

Receptor (Olfactory Pathway)

Bipolar neurons in olfactory epithelium detect odorants

Relay (Olfactory Pathway)

Axons form olfactory nerve (CN I)

Initial Processing (Olfactory Pathway)

Signals enter olfactory bulbs

Olfactory Tract (Olfactory Pathway)

Signals travel along olfactory tract

Unique Feature (Olfactory Pathway)

Does NOT pass through thalamus

Cerebral Destination (Olfactory Pathway)

Olfactory cortex in temporal lobe

Limbic Integration (Olfactory Pathway)

Signals sent to limbic system for emotion/memory

Sympathetic Chain Ganglia

Distribute sympathetic output to thorax, head, neck, and limbs

Collateral Ganglia

Distribute sympathetic output to abdominopelvic organs

Adrenal Medulla Pathway

Preganglionic fibers synapse with chromaffin cells

Adrenal Medulla Response

Releases epinephrine and norepinephrine into bloodstream

Intramural Ganglia

Parasympathetic ganglia located within organ walls

Pelvic Nerves

Carry parasympathetic preganglionic fibers from S2–S4