BIO25. Ch.15 Autonomic Nervous System Flashcards

Flashcards for Anatomy & Physiology Chapter 15 Lecture Review

Somatic Nervous System (SNS)

Consciously perceived or controlled processes; detects signals from special senses and skin/proprioceptors; sends signals from CNS to skeletal muscles.

Autonomic Nervous System (ANS)

Also called autonomic motor or visceral motor system; regulates processes below conscious level; transmits signals from CNS to heart, smooth muscle, glands; maintains homeostasis.

Somatic Motor Neuron

A single lower motor neuron extends from CNS to skeletal muscle fibers, releases acetylcholine (ACh) to excite muscle fiber.

Autonomic Motor Neuron

A two-neuron chain: preganglionic neuron (ACh) and ganglionic neuron (ACh or NE) to reach effector organs; allows for neuronal convergence and divergence.

Preganglionic Neuron

The first neuron in the autonomic nervous system pathway, its cell body is within the brainstem or spinal cord.

Ganglionic (Postganglionic) Neuron

The second neuron in the autonomic nervous system pathway, its cell body is within autonomic ganglion, releases ACh or NE.

Neuronal Convergence (ANS)

Multiple preganglionic neurons synapsing on one ganglionic neuron.

Neuronal Divergence (ANS)

Branches of axon from one preganglionic neuron synapsing with numerous ganglionic neurons.

Hypothalamus (ANS Control)

Crucial brain region controlling both divisions of the ANS, essential for emotional ANS processes (fight-or-flight).

Brainstem Nuclei (ANS Control)

Mediate visceral reflexes, such as maintenance of blood pressure.

Spinal Cord (ANS Control)

Governs some ANS reflexes, such as defecation and urination.

Parasympathetic Division

"Rest-and-digest"; conserves energy, replenishes nutrients.

Sympathetic Division

"Fight-or-flight"; prepares the body for exercise, excitement, emergency.

Craniosacral Division

Another name for the Parasympathetic division, referring to the origin of preganglionic neurons.

Thoracolumbar Division

Another name for the Sympathetic division, referring to the origin of preganglionic neurons.

Oculomotor Nerve (CN III)

Parasympathetic; controls ciliary muscle (lens focus) and pupil constriction.

Facial Nerve (CN VII)

Parasympathetic; controls lacrimal glands, small glands of nose/mouth, and submandibular/sublingual salivary glands.

Glossopharyngeal Nerve (CN IX)

Parasympathetic; preganglionic axons extend to otic ganglion near ear.

Vagus Nerve (CN X)

Parasympathetic; slows heart rate, constricts lung bronchioles, increases digestive secretions, stores carbohydrates.

Pelvic Splanchnic Nerves

Parasympathetic; effects include smooth muscle contraction, increased secretions in urinary and digestive systems.

Horner Syndrome

Injury of cervical sympathetic trunk; symptoms: ptosis, miosis, anhydrosis, facial flushing.

Spinal Nerve Pathway (Sympathetic)

For skin effectors (sweat glands) of neck, torso, and limbs; postganglionic axon travels through gray ramus.

Postganglionic Sympathetic Nerve Pathway

For internal organs of thorax and neck, skin effectors of head and neck, eyelid and dilator pupillae muscles; does not leave the trunk via grey ramus.

Splanchnic Nerve Pathway

For effectors in abdominal and pelvic viscera; preganglionic axons pass sympathetic trunk without synapsing.

Sympathetic Stimulation (Cardiovascular)

Increases heart rate and force of contraction, vasodilation in coronary arteries.

Sympathetic Stimulation (Digestive)

More viscous saliva produced, decreased motility of GI tract wall, inhibits insulin release, stimulates glucagon release.

Sympathetic Stimulation (Integumentary)

Arrector pili contraction (goosebumps), sweat gland release, blood vessel vasoconstriction.

Sympathetic Stimulation (Respiratory)

Bronchi/bronchioles dilation to increase airflow.

Sympathetic Stimulation (Urinary)

Urinary bladder retention of urine, kidney release of renin.

Sympathetic Stimulation (Reproductive)

Release of secretions in male during ejaculation, contraction of uterus and vagina walls during orgasm.

Cholinergic Neurons

Release acetylcholine (ACh); include all ANS preganglionic neurons, all parasympathetic ganglionic neurons, and sympathetic ganglionic neurons innervating sweat glands and blood vessels in skeletal muscle.

Adrenergic Neurons

Release norepinephrine (NE); most sympathetic ganglionic neurons are adrenergic.

Autonomic Reflexes (Visceral Reflexes)

Pre-programmed response to a stimulus generated by a reflex arc.

Cardiovascular Reflex

Stretch receptors respond to pressure elevation, signals sent to cardiac center in medulla oblongata, inhibits sympathetic, activates parasympathetic output, slows heart rate, decreases blood pressure.

Micturition Reflex

Stretch receptors signal when bladder fills with urine, signals sent to sacral spinal cord, results in reflexive contraction of smooth muscles in bladder and relaxation of urinary sphincters.

Autonomic Dysreflexia

Causes blood pressure to rise profoundly after spinal cord injury at or superior to the T6 vertebra.

Somatic Sensory Portion

Detects signals from special senses (vision, hearing, equilibrium, smell, taste) and from skin and proprioceptors.

Somatic Motor Portion

Sends signals from CNS to skeletal muscles.

Voluntary Movements

Involve the cerebrum.

Reflexive Movements

Involve the brainstem and spinal cord.

Visceral Sensory Inputs

Sensory information from blood vessels.

Optimal Ranges

Homeostasis keeps conditions inside the body in these conditions.

Myelinated Axon with Large Diameter

Characteristic of lower motor neurons of the somatic nervous system.

Acetylcholine (ACh)

Neurotransmitter released from synaptic knob to excite muscle fiber in the somatic nervous system.

Chain of Two Motor Neurons

How the autonomic nervous system reaches the effector.

Thin, Myelinated Axon

Projects to autonomic ganglion in peripheral nervous system, characteristic of the preganglionic neuron.

Very Thin, Unmyelinated Axon

Projects to cardiac muscle, smooth muscle, or gland, characteristic of the ganglionic neuron.

Norepinephrine (NE)

Neurotransmitter released from synaptic knob to either excite or inhibit the effector.

Neuronal Convergence

Multiple preganglionic neurons synapsing on one ganglionic neuron.

Neuronal Divergence

Branches of axon from one preganglionic neuron synapsing with numerous ganglionic neurons.

Areas of Cortex, Thalamus, Limbic System

Influence the hypothalamus.

Visceral Reflexes

Mediated by brainstem nuclei.

Defecation and Urination

Governed by the spinal cord as controlled by the parasympathetic nervous system.

Integration and Command Center for Autonomic Function

CNS structure.

Conserving Energy, Replenishing Nutrients

For the parasympathetic division.

Exercise, Excitement, Emergency

For the sympathetic division.

Preganglionic Neurons in Brainstem or S2-S4 Spinal Cord

Origin for parasympathetic division.

Preganglionic Axons are Long, Postganglionic Axons are Short

Characteristic of the parasympathetic division.

Ganglia are Close to or Within the Effector Organ

Location of ganglia in the parasympathetic division.

Preganglionic Axons have Few Branches

Branching characteristic of the parasympathetic division.

Helps Maintain Homeostasis

Primary function of the Parasympathetic

Preganglionic Neuron in Lateral Horns of T1-L2

Origin for sympathetic division.

Preganglionic Axons are Short, Postganglionic Axons are Long

Characteristic of the sympathetic division.

Ganglia are Close to Spinal Cord

Location of ganglia in the sympathetic division.

Preganglionic Axons have Many Branches

Branching characteristic of the sympathetic division.

Ciliary Ganglion

Location of post ganglionic axons that control ciliary muscle and pupil constriction

Pterygopalatine and Submandibular Ganglia

Location of post ganglionic axons that control lacrimal glands and small glands of nose and mouth

Otic Ganglion

Location of post ganglionic axons near the ear

Ganglia in the Thorax and Abdomen

Location of post ganglionic axons that control heart rate, constricting lung bronchioles, increasing digestive secretions, storing carbohydrates

Terminal or Intramural Ganglia

Location of ganglionic neurons for pelvic splanchnic nerves.

Hypogastric Plexus

Contributed to by the pelvic splanchnic nerves

Effects of Pelvic Splanchnic Nerves

Smooth muscle contraction, increased secretions in urinary and digestive systems

Ganglia are Close to spinal cord

Anatomical feature of the sympathetic division.

Complex

Anatomical Path of the sympathetic division.

Drooping of Superior Eyelid

One symptom of the Horner syndrome

Superior Tarsal Muscle

Paralysis of this muscle causes drooping of the superior eyelid

Constricted Pupil

One symptom of Horner's syndrom

Pupil dilator muscle

Paralysis of the muscle results in constricted pupil

Sweat glands not receiving sympathetic innervation

Causes of lack of sweating in Horner syndrome

Lack of Sympathetic Innervation

Results in vasodilation

Skin effectors of Neck, Torso, and Limbs

Location of the Spinal nerve pathway effectors

Enters sympathetic trunk ganglion and synapses with ganglionic neuron

Action of the preganglionic neuron in the Spinal nerve pathway

Travels through gray ramus at same spinal level

Action of the postganglionic axon in the spinal nerve pathway.

Effectors that are Internal Organs of Thorax and Neck

Location of the Postganglionic sympathetic nerve pathway effectors

Skin Effectors of Head and Neck

Location of the Postganglionic sympathetic nerve pathway effectors

Eyelid and dilator pupillae muscles

Location of the Postganglionic sympathetic nerve pathway effectors

Enters and synapses in sympathetic trunk ganglion

Action of the preganglionic neuron in the Postganglionic sympathetic nerve pathway

Goes directly from trunk ganglion to effector

Action of the postganglionic axon in the Postganglionic sympathetic nerve pathway

Does not leave trunk via grey ramus

Characteristic of the postganglionic sympathetic nerve pathway

Effectors in Abdominal and Pelvic Viscera

Location of the Splanchnic nerve pathway effectors

Pass sympathetic trunk without synapsing

Action of the preganglionic axons in the Splanchnic nerve pathway

Travel in splanchnic nerves to prevertebral ganglia

Action of the axons in the Splanchnic nerve pathway

Increase heart rate and force of contraction

Effect of the sympathetic division on the cardiovascular system

More viscous saliva produced

Effect of sympathetic division on the digestive system

Glycogenolysis

Effect of sympathetic division on the digestive system and liver

contraction, causing goosebumps

Effect of the sympathetic division on the integumentary system

dilation to increase airflow

Effect of the sympathetic division on the respiratory system

Contraction of walls during orgasm

Effect of the sympathetic division on the reproductive system

acetylcholine (ACh) and norepinephrine (NE)

ANS neurotransmitters

Either neurotransmitter can cause stimulation or inhibition

Effect of the ANS neurotransmitters