Autonomic Nervous System Flashcards
Which division of the PNS corresponds to the autonomic NS?
Visceral motor system
What does the autonomic nervous system control?
Glands, cardiac muscle, smooth muscle
What are the two branches of the autonomic nervous system (ANS), and what physiological responses does each of them regulate?
- Parasympathetic NS: Rest & digest response
- Sympathetic NS: Flight-or-fight stress response
What are the effects of sympathetic activation?
Pupils dilate, salvation is inhibited, bronchi relax, heart rate increases, digestive activity is inhibited, increased release of glucose, increased EPI & NE secretion, inhibition of urination.
What constitutes the primary distinction in the definitions of visceral and somatic reflexes?
Visceral reflexes are initiated by stimulus in the viscera.
What are the 5 components of a visceral reflex arc?
- Receptors (in viscera)
- Afferent (sensory) neuron
- Interneuron
- Efferent (motor) neuron
- Effector (viscera)
What types of stimuli are detected by receptors in the viscera?
Stretch, tissue damage, blood chemistry, body temperature, and other internal stimuli
What is an autonomic ganglion? What does it connect?
Autonomic ganglia transmit action potential originating in the CNS to the PNS; connects preganglionic neuron to post ganglionic neuron
From which specific site with in the CNS does the perganglionic fiber originate?
Either the lateral horn neurons in the spinal cord, or a cranial nucleus in the brainstem
What division of the autonomic nervous system do the paravertebral ganglia belong to?
Sympathetic
Where is the paravertebral ganglia?
Adjacent to both sides of the vertebral column from the cervical to coccygeal level
From which segments of the spinal cord do preganglionic neurons originate?
Thoracic and lumbar regions
Which division of the autonomic nervous is referred to as the “thoracolumbar division,” and which one is known as the “craniosacral division”?
Thoracolumbar division is associated with the sympathetic nervous system, and the craniosacral division is associated with the parasympathetic nervous system, depending on the region from which the preganglionic fiber emerges.
When considering cranial reflexes involving cranial nerves III, VII, IX and X, which division the autonomic nervous system primarily controls theses reflexes?
The parasympathetic nervous primarily controls these reflexes. In this reflex arc, the preganglionic neuronal cell body is located in cranial nuclei within the brainstem, rather than the spinal cord.
Which of the two divisions of the ANS possesses shorter preganglionic axons?
Pre-ganglionic is shorter in the sympathetic nervous system; post-ganglion is shorter in the parasympathetic nervous system
Which of the two divisions of the ANS has the ganglia (or ganglion) located closer to the CNS?
The sympathetic nervous system; the parasympathetic nervous system is close to the visceral organ
Neural divergance
A phenomenon in the nervous system where a single neuron sends signals to multiple target neurons or effector cells ;greater in the sympathetic nervous system
What are the three pathways that sympathetic fibers can take after entering the sympathetic chain ganglia?
Spinal nerve route, Sympathetic nerve route, and Splanchnic Nerve Route
Describe the spinal nerve route.
Preganglionic fibers exit through the ventral root and traverse the spinal nerve. Upon reaching the autonomic ganglion within sympathetic track, the axon penetrates it via the white ramus communicans. Fibers immediately synapse with post ganglionic neuron that return to the spinal nerve via the gray ramus communicans.
Describe the synaptic nerve route.
Fibers have the ability to ascend or descend and form synapses at ganglia at different vertebral levels.
Describe the splanchnic nerve route.
Preganglionic fibers continue as splanchnic nerves beyond the ganglia and traverse that sympathetic trunk to establish synapses within collateral ganglion.
Does the sympathetic nervous system (SNS) or parasympathetic nervous system (PSNS) innervate the adrenal gland?
The SNS, often known as the “sympathoadrenal system,” innervates the adrenal gland.
What are the two types of sympathetic or adrenergic receptors, and which neurotransmitter do they bind to?
Alpha and beta receptors, which bind to epinephrine and norepinephrine.
What are the differences between alpha 1 and alpha 2 receptors?
Alpha 1 receptors produce sympathetic, excitatory responses, while alpha 2 receptors are paired with the inhibitory Gi protein.
What are the two types of cholinergic receptors, and which neurotransmitter do they bind to?
Nicotinic (skeletal muscles, ans ganglia ) and muscarinic receptors (effector organs, heart) , which bond to acetylcholine.
What are collateral ganglia?
Sympathetic ganglia which lie between the sympathetic chain and the target organ; related to the abdominal cavity
How do thermoregulatory sweating and stress sweating differ?
Thermoregulatory sweating is initiated by cholinergic input while stress induced sweating is stimulated by adrenergic input.
