Autonomic and Somatic Nervous Systems Quiz

Autonomic Nervous System

• The autonomic nervous system (ANS) is a component of the peripheral nervous system
• It regulates involuntary functions, including heart rate, digestion, and blood pressure
• The ANS is divided into two branches: sympathetic and parasympathetic
• The structure and function of the autonomic nervous system (ANS) are examined
• The somatic and ANS are compared and contrasted
• ANS neurotransmitters are examined
• The sympathetic and parasympathetic nervous systems are compared and contrasted

Comparison of Somatic and Autonomic Nervous Systems

• The somatic nervous system includes sensory and motor neurons; responsible for voluntary movement
• Sensory neurons are related to touch, pain, temperature, and proprioception; sight, hearing, taste, smell and equilibrium
• Motor neurons innervate skeletal muscles; voluntary activity.
• The autonomic nervous system receives input from various sensory receptors (tissues, blood vessels, organs, etc.) controls involuntary functions

Anatomy of Autonomic Motor Pathways

• The autonomic nervous system usually uses a two-neuron pathway:
• Preganglionic neuron: cell body in central nervous system, axon goes to a ganglion
• Postganglionic neuron: cell body in ganglion, axon extends to effector

Divisions of the ANS

• The sympathetic division (fight-or-flight): increases alertness and metabolism; preparing for emergencies
• The parasympathetic division (rest-and-digest): slows down body activity; returns the body to normal after a stressful episode

ANS Neurotransmitters and Receptors

• Cholinergic neurons release acetylcholine.
• Cholinergic receptors include nicotinic and muscarinic receptors.
• Adrenergic neurons release norepinephrine, which has receptors called alpha1, alpha2, beta1, beta2

Physiology of the ANS

• Autonomic tone is the balance between sympathetic and parasympathetic activity; regulated by the hypothalamus
• Sympathetic stimulation leads to physiological changes like increased heart rate, and dilation of pupils.
• Parasympathetic stimulation often has the opposite effects, examples include decreased heart rate.

Integration and Control of Autonomic Functions

• Functions like heart rate, blood pressure, and blood vessel diameter are controlled by autonomic reflexes occurring across the autonomic reflex arc
• This arc includes components like receptors, sensory neurons, integrating centers, motor neurons, and effectors
• A more in-depth understanding of this arc is presented in the next pages, including a diagram of this system and the interactions involved

Stress Response

• Stressors can activate the nervous system, leading to various physical and emotional changes

The Autonomic Nervous System and Homeostasis

• The ANS plays crucial roles in maintaining homeostasis as it regulates various body functions and interacts with other body systems (digestive, cardiovascular, respiratory, etc.)
• The ANS also regulates various body systems like the Integumentary, Skeletal, Muscular, Endocrine, and more.
• The ANS interacts with various other systems in the human body for complete homeostasis

Raynaud Phenomenon

• Excessive sympathetic stimulation of the arterioles in the digits cause vasoconstriction, leading to numbness and ischemia in the affected digits.