Podcast
Questions and Answers
Which statement correctly describes the origin of the sympathetic nervous system?
Which statement correctly describes the origin of the sympathetic nervous system?
What characterizes the parasympathetic division of the autonomic nervous system?
What characterizes the parasympathetic division of the autonomic nervous system?
What is one of the main functions of autonomic ganglia?
What is one of the main functions of autonomic ganglia?
Which ganglia location is not associated with the sympathetic nervous system?
Which ganglia location is not associated with the sympathetic nervous system?
Signup and view all the answers
What is the primary effect of parasympathomimetic drugs like acetylcholine?
What is the primary effect of parasympathomimetic drugs like acetylcholine?
Signup and view all the answers
Which of the following statements about adrenergic receptors is correct?
Which of the following statements about adrenergic receptors is correct?
Signup and view all the answers
What role do ganglion blockers like nicotine in large doses play?
What role do ganglion blockers like nicotine in large doses play?
Signup and view all the answers
What is a common use for atropine, a parasympatholytic drug?
What is a common use for atropine, a parasympatholytic drug?
Signup and view all the answers
Which option correctly describes the formation of noradrenaline?
Which option correctly describes the formation of noradrenaline?
Signup and view all the answers
What effect do beta-1 receptors have when stimulated?
What effect do beta-1 receptors have when stimulated?
Signup and view all the answers
How do sympatholytic drugs like phentolamine function?
How do sympatholytic drugs like phentolamine function?
Signup and view all the answers
Which statement correctly describes the release of acetylcholine (Ach)?
Which statement correctly describes the release of acetylcholine (Ach)?
Signup and view all the answers
Which anatomical locations are typically associated with parasympathetic ganglia?
Which anatomical locations are typically associated with parasympathetic ganglia?
Signup and view all the answers
What is the primary effect of the sympathetic nervous system?
What is the primary effect of the sympathetic nervous system?
Signup and view all the answers
Which one of the following organs does NOT have a parasympathetic supply?
Which one of the following organs does NOT have a parasympathetic supply?
Signup and view all the answers
Which chemical transmitter is secreted by cholinergic neurons at the end of their fibers?
Which chemical transmitter is secreted by cholinergic neurons at the end of their fibers?
Signup and view all the answers
In terms of autonomic control, which statement is true regarding the organization of the nervous system?
In terms of autonomic control, which statement is true regarding the organization of the nervous system?
Signup and view all the answers
Which of the following organs is primarily affected by the sympathetic nervous system's response to stress?
Which of the following organs is primarily affected by the sympathetic nervous system's response to stress?
Signup and view all the answers
Which neurotransmitter is secreted during the fight-or-flight response?
Which neurotransmitter is secreted during the fight-or-flight response?
Signup and view all the answers
Study Notes
Autonomic Nervous System
- The autonomic nervous system (ANS) is responsible for regulating involuntary bodily functions
- The ANS is divided into two main branches: the sympathetic and parasympathetic nervous systems
Sympathetic Nervous System
- Originates from the lateral horn of all thoracic segments and the upper two lumbar segments (thoraco-lumbar outflow)
- Contains a chain ganglia and collateral ganglia that innervate various organs (heart, lungs, digestive system, etc.)
- Postganglionic fibers project to spinal nerves innervating structures like skin, blood vessels, sweat glands, muscle tissue
- The sympathetic system often elicits widespread effects, creating "fight or flight" responses
Parasympathetic Nervous System
- Has two origins: cranial nerves (III, VII, IX, and X) and sacral segments (S2-S4; craniosacral outflow).
- Parasympathetic ganglia are usually located near or within the organs they innervate (terminal ganglia).
- Postganglionic fibers are usually short, which means effects are localized, and tend to have an overall calming effect on the body. This allows for "rest and digest" functions like digestion and rest.
Autonomic Ganglia
- Ganglia act as relay stations and distribution centers for the ANS.
- They house synapses between preganglionic and postganglionic neurons
- Different types of ganglia exist, categorized as lateral (sympathetic chain) ganglia and co-lateral/terminal ganglia.
- Different ganglia are located in various places in the body to control the function of certain organs
Functions of Autonomic Ganglia
- Relay stations where ANS functions can be controlled
- Distribution centers, each preganglionic nerve fiber relays with 8–9 postganglionic neurons
- Sympathetic ganglia are mostly located in the sympathetic chain (lateral ganglia) or in collateral ganglia
Types of Chemical Transmitters
- Acetylcholine (ACh) is a chemical transmitter secreted by cholinergic neurons.
- Nor-adrenaline (NA) is secreted by adrenergic neurons.
Sites of Release of Acetylcholine
- Acetylcholine (ACh) is released at all autonomic ganglia (both sympathetic and parasympathetic).
- Acetylcholine (ACh) is released at the end of parasympathetic postganglionic fibers.
- Acetylcholine (ACh) is released at the end of sympathetic postganglionic fibers that innervate blood vessels of skeletal muscle, sweat glands, and the adrenal medulla
Drugs Affecting the Nervous System
- Ganglion stimulants use small doses of nicotine, while ganglion blockers use high doses.
- Parasympathomimetic drugs mimic parasympathetic responses and include ACh and methacholine
Muscarinic Drugs
- These drugs stimulate peripheral cholinergic receptors
- An example is muscarine, a substance that stimulates muscarinic receptors
Parasympatholytic Drugs
- These drugs block muscarinic-like actions of ACh
- Atropine is an example of a parasympatholytic drug
Noradrenaline
- Noradrenaline is formed from the amino acid phenylalanine.
- Released by postganglionic sympathetic fibers (with exceptions)
- Adrenergic receptors, which are found in effector organs, either cause vasoconstriction or vasodilation
- Can cause either heart contraction or lung/bronchial relaxation, depending on the specific receptors involved
Sympathomimetic Drugs
- These drugs stimulate beta 1 & 2 receptors, including isoprenaline.
- Isoprenaline is not specific because it works on both beta 1 and 2 receptors.
Sympatholytic Drugs
- Alpha blockers block alpha 1 receptors (e.g., phentolamine)
- Beta 1 receptor blockers (e.g., atenolol) are antihypertensive drugs
- Beta 1 and 2 blockers, including propranolol (Inderal), are also commonly used to manage hypertension or other conditions
Special Features of Autonomic Nerves
- They control the activity of visceral organs
- They show a baseline level of discharge
- Sympathetic stimulation generally affects many areas, while parasympathetic effects are more localized
Non-adrenergic Non-cholinergic Autonomic Neurons
- Found in the intrinsic nerves of the gut (enteric nervous system)
- Release peptide transmitters (e.g., encephalin, GABA, NO)
- Function in regulating gut motility and the release of gut hormones
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on the autonomic nervous system, including the sympathetic and parasympathetic divisions. This quiz covers the origins, functions, and characteristics of autonomic ganglia. Challenge yourself and deepen your understanding of how these systems interact in the body.
