Autonomic Nervous System, Reflexes, and Motor Pathways: Key Concepts for Biology

parasympathetic nervous system

the division of the autonomic nervous system that calms the body, conserving its energy

pelvic nerves

preganglionic fibers from sacral segments that innervate distal large intestine, urinary and reproductive systems

sympathetic chain ganglia

Bulges on the sympathetic chain composed of neuronal cell bodies.

Collateral Ganglia

Are anterior to vertebral bodies

Contain ganglionic neurons that innervate tissues and organs in abdominopelvic cavity

adrenal medulla

secretes epinephrine and norepinephrine

Sympathetic Division

fight or flight

Preganglionic Neurons

conduct impulses between the spinal cord and a ganglion

Ganglionic Neurons

Release neurotransmitters at specific target organs

postganglionic neuron

neurons of the autonomic nervous system that form synapses directly with their target organ

corticospinal

descending tract whose fibers conduct motor impulses to skeletal muscles

medial pathway

help control gross movements of trunk and proximal limb muscles

Motor Homunculus

the body map on the motor cortex

sensory homunculus

map showing the amount of sensory cortex devoted to each body region

Babinski sign

The toes flex upward when sole of foot is stimulated, indicating motor nerve damage.

withdrawal reflex

a spinal reflex that pulls a body part away from a source of pain

monosynaptic reflex

reciprocal inhibition

The simultaneous contraction of one muscle and the relaxation of its antagonist to allow movement to take place