Podcast
Questions and Answers
What is the primary function of the autonomic nervous system (ANS)?
What is the primary function of the autonomic nervous system (ANS)?
- To consciously control skeletal muscle movement.
- To regulate involuntary bodily functions and maintain homeostasis. (correct)
- To process sensory information from the external environment.
- To facilitate rapid communication between the brain and spinal cord.
Which of the following physiological responses is most likely associated with the sympathetic nervous system?
Which of the following physiological responses is most likely associated with the sympathetic nervous system?
- Increased digestive activity.
- Pupil constriction.
- Decreased heart rate.
- Elevated blood pressure and alertness. (correct)
In a visceral reflex arc, what is the role of the afferent neuron?
In a visceral reflex arc, what is the role of the afferent neuron?
- To transmit sensory information from the receptor to the central nervous system. (correct)
- To carry motor commands to the effector organ.
- To directly stimulate the target tissue.
- To integrate sensory information within the spinal cord.
What does 'autonomic tone' refer to in the context of the autonomic nervous system?
What does 'autonomic tone' refer to in the context of the autonomic nervous system?
Which of the following best illustrates a function primarily controlled by the parasympathetic nervous system?
Which of the following best illustrates a function primarily controlled by the parasympathetic nervous system?
Which characteristic is associated with the preganglionic fibers of the sympathetic nervous system?
Which characteristic is associated with the preganglionic fibers of the sympathetic nervous system?
What anatomical feature facilitates the wide distribution of neurotransmitters in the autonomic nervous system?
What anatomical feature facilitates the wide distribution of neurotransmitters in the autonomic nervous system?
Which route do postganglionic sympathetic fibers take to reach sweat glands in the skin?
Which route do postganglionic sympathetic fibers take to reach sweat glands in the skin?
How does the splanchnic nerve route differ from the spinal nerve route in the sympathetic nervous system?
How does the splanchnic nerve route differ from the spinal nerve route in the sympathetic nervous system?
Which ganglia are part of the splanchnic nerve route?
Which ganglia are part of the splanchnic nerve route?
What is the primary function of the adrenal medulla in the sympathetic nervous system?
What is the primary function of the adrenal medulla in the sympathetic nervous system?
How does the parasympathetic nervous system (PSNS) achieve more specific control compared to the sympathetic nervous system (SNS)?
How does the parasympathetic nervous system (PSNS) achieve more specific control compared to the sympathetic nervous system (SNS)?
What is a key feature of the enteric nervous system (ENS) that distinguishes it from other parts of the peripheral nervous system?
What is a key feature of the enteric nervous system (ENS) that distinguishes it from other parts of the peripheral nervous system?
The peristaltic reflex involves a coordinated response in the gastrointestinal tract. Which component is responsible for the secretomotor and vasodilator reflexes?
The peristaltic reflex involves a coordinated response in the gastrointestinal tract. Which component is responsible for the secretomotor and vasodilator reflexes?
In Hirschsprung's disease, the absence of the enteric plexus in the sigmoid colon and rectum leads to specific functional consequences. What is the primary physiological result of this absence?
In Hirschsprung's disease, the absence of the enteric plexus in the sigmoid colon and rectum leads to specific functional consequences. What is the primary physiological result of this absence?
A patient is diagnosed with Hirschsprung's disease. Upon examination, what anatomical changes in the colon would be expected proximal to the affected segment?
A patient is diagnosed with Hirschsprung's disease. Upon examination, what anatomical changes in the colon would be expected proximal to the affected segment?
Adult Zonal Hirschsprung's Disease presents a diagnostic challenge often involving a specific region of the colon. Which areas are typically observed as grossly dilated during emergency exploration in these cases?
Adult Zonal Hirschsprung's Disease presents a diagnostic challenge often involving a specific region of the colon. Which areas are typically observed as grossly dilated during emergency exploration in these cases?
The contrasting effects of the sympathetic (SNS) and parasympathetic (PSNS) nervous systems are mediated by different neurotransmitters and receptor types. What is the primary reason for these differing effects?
The contrasting effects of the sympathetic (SNS) and parasympathetic (PSNS) nervous systems are mediated by different neurotransmitters and receptor types. What is the primary reason for these differing effects?
Acetylcholine (ACh) acts on two main classes of receptors: muscarinic and nicotinic. Which of the following accurately describes the signaling mechanism of muscarinic receptors?
Acetylcholine (ACh) acts on two main classes of receptors: muscarinic and nicotinic. Which of the following accurately describes the signaling mechanism of muscarinic receptors?
Nicotinic receptors are a class of acetylcholine receptors found at various locations in the body. Which of the following is the correct mechanism of action for nicotinic receptors?
Nicotinic receptors are a class of acetylcholine receptors found at various locations in the body. Which of the following is the correct mechanism of action for nicotinic receptors?
Norepinephrine (NE) primarily acts on adrenergic receptors, which are divided into α and β types. How do α-adrenergic receptors typically mediate their effects?
Norepinephrine (NE) primarily acts on adrenergic receptors, which are divided into α and β types. How do α-adrenergic receptors typically mediate their effects?
Flashcards
Autonomic Nervous System (ANS)
Autonomic Nervous System (ANS)
Involuntary motor system that modulates the activity of glands, cardiac muscle, and smooth muscle to regulate homeostasis.
Visceral Reflex Arc
Visceral Reflex Arc
Sensory receptor, afferent neuron, interneuron, efferent neuron and effector, but slower than somatic reflexes.
Sympathetic Division
Sympathetic Division
Increases alertness, heart rate, and blood pressure; prepares the body for 'fight or flight'.
Parasympathetic Division
Parasympathetic Division
Signup and view all the flashcards
Autonomic Tone
Autonomic Tone
Signup and view all the flashcards
Sympathetic Nervous System
Sympathetic Nervous System
Signup and view all the flashcards
Preganglionic Fiber
Preganglionic Fiber
Signup and view all the flashcards
Postganglionic Fiber
Postganglionic Fiber
Signup and view all the flashcards
Varicosities
Varicosities
Signup and view all the flashcards
Sympathetic Ganglion Chains
Sympathetic Ganglion Chains
Signup and view all the flashcards
White Rami
White Rami
Signup and view all the flashcards
Gray Rami
Gray Rami
Signup and view all the flashcards
Parasympathetic Nervous System
Parasympathetic Nervous System
Signup and view all the flashcards
Peristalsis
Peristalsis
Signup and view all the flashcards
Peristaltic Reflex
Peristaltic Reflex
Signup and view all the flashcards
IPANs
IPANs
Signup and view all the flashcards
Hirschsprung Disease
Hirschsprung Disease
Signup and view all the flashcards
Megacolon
Megacolon
Signup and view all the flashcards
ANS Effect Differences
ANS Effect Differences
Signup and view all the flashcards
Acetylcholine (ACh)
Acetylcholine (ACh)
Signup and view all the flashcards
α-adrenergic Receptors
α-adrenergic Receptors
Signup and view all the flashcards
Study Notes
Autonomic Nervous System (ANS)
- Involuntary motor (visceral) system that modulates activity
- Adjusts glands and cardiac and smooth muscle
- Regulates homeostasis - heart rate, blood pressure, respiration, digestion, pupil diameter, and metabolism
Visceral Reflexes
- Similar to Somatic reflexes
- Slower responses
- Components including the receptor, afferent sensory neurons, integration center (interneurons), efferent motor neurons, and effector
Divisions of ANS
- Sympathetic division promotes alertness, increased heart rate, and elevated blood pressure
- Active during exercise, competition, stress, anger, and fear promoting a fight-or-flight response
- Parasympathetic division reduces energy usage and maintains body functions like digestion and waste removal, promoting a resting and digesting state
- Neither division has universally excitatory or inhibitory effects
- Autonomic tone is a normal background rate, in which the Parasympathetic controls smooth muscles in intestines and slows heart rate and maintains muscle tone and heart rate ~70-80 bpm
- Sympathetic division partially constricts blood vessels, maintaining blood pressure
ANS Components
- Central nervous system - control nuclei in the hypothallus and other brainstem regions and motor neurons in the spinal cord
- Peripheral nervous system - ganglion and two fibers to target organ
- Preganglionic fibers are myelinated fibers that release ACh in Soma in CNS
- Postganglionic fibers are unmyelinated fibers that extends to effector and releases Ach or NE
Varicosities
- Terminal portions of autonomic nerve fibers
- Neurotransmitters are released along a significant length of the axon to a large surface area of effector tissue, in a "looser", more easily diffused manner
Sympathetic Division (SNS)
- Originates in thoracic and lumbar regions (T1 to L2) of the spinal cord
- Fibers extend to every level of the body
- Ganglion chains (paravertebral) with longitudinal ganglia, Cervical to coccygeal levels
- Has short preganglionic fibers (myelinated via White Rami)
- Has long postganglionic fibers (unmyelinated via Gray Rami)
White and Grey rami
- Contains myelinated fibers (White rami) and unmyelinated fibers (Grey rami)
Leaving Sympathetic Ganglia
- Spinal Nerves route which includes Gray ramus that returns signal to spinal nerve and target organ
- Sympathetic Nerve route through Sympathetic nerves carotid or cardiac plexus that target organs
- Splanchnic nerve route with no ganglia synapse that continue as splanchnic nerves collateral
Collateral Ganglia
- Splanchnic nerve route with Celiac, Superior mesenteric, and Inferior mesenteric ganglia
- Fibers are located at points where arteries with the same names branch off aorta
- Postganglionic fibers accompany these arteries and their branches to the target
Adrenal Gland
- Medulla acts as a sympathetic ganglion, forming a "Sympathoadrenal system" - which has postganglionic neurons and is neuroendocrine
- Stimulated by preganglionic sympathetic fibers to secrete epinephrine
Parasympathetic Division (PSNS)
- Fibers originate from brain and sacral region with ganglia near target organs
- Long preganglionic fibers, with divergence of neurons closer to organ
- Fewer postganglionic fibers with more specific stimulation control
Enteric Nervous System
- Digestive tract with ~500 million neurons, that communicates and coordinates smooth muscle and glands
- Independent from CNS, with its own ganglia and reflex arcs
- Regulated by PSNS and SNS
- Involved in movement in the Esophagus, Stomach and Intestines
Peristaltic Reflex
- Local stimulation which includes Ascending excitatory reflex and Descending inhibitory reflex
Hirschsprung Disease
- Hereditary absence of enteric plexus, specifically no innervation in sigmoid colon and rectum
- Constricts permanently and does not allow passage of feces, which becomes impacted above the constriction
- Leads to a shrunken rectum, Megacolon, and massive colon dilation with chronic constipation
Neurotransmitters & Receptors
- Divisions & Contrasting effects which has distinctions between & within SNS & PSNS
- There are different neurotransmitters (NTs) including Acetylcholine and Norepinephrine
- Different receptor types include two classes for each type of neurotransmitter
Acetylcholine (ACh)
- Found preganglionic in both ANS divisions and Postganglionic in parasympathetic
- Found in some Sympathetic (blood vessels, some glands)
- Muscarine receptors create second messenger systems in Cardiac and smooth muscle
- Muscarine receptor subclasses excites intestinal muscle and inhibits cardiac muscle
- Nicotinic receptors are Ligand-gated channels in Ganglia synapses and the Adrenal medulla
Norepinephrine (NE)
- Found postganglionic in Sympathetic
- α-adrenergic receptors trigger second messenger systems, which can have different subclasses
- Usually produces excitatory effects (e.g., labor contractions)
- Can be inhibitory (e.g., lowers intestinal motility) which prevents cAMP production
- β-adrenergic receptors usually act on inhibitory effects (e.g., dilating bronchioles, relaxes), and various subclasses can be excitatory (e.g., excites cardiac)
Dual Innervation
- Nerve fibers from both divisions with is Antagonistic in same effector cells - e.g., heart muscle cells and different cells - e.g., eye muscles
- Cooperative action includes different effectors that have unified response, e.g., saliva production
Single Innervation
- Nerve fibers from one division that can also produce opposite effects when needed
- During emergency/stress, blood routes during emergency/stress, sympathetic fibers decrease firing rate
- Smooth muscles relax (blood vessels) and blood pressure pushes on walls dilation
- Vessels leading to vital organs (brain, heart,) can dilate
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
The autonomic nervous system is an involuntary motor system that modulates activity and adjusts glands along with cardiac and smooth muscle. It regulates homeostasis, including heart rate, blood pressure, respiration, digestion, pupil diameter, and metabolism.The sympathetic division promotes alertness, increased heart rate, and elevated blood pressure promoting a fight-or-flight response.
