PCOL - ANS

• A neuron is the basic functional unit of the nervous system, with parts including the cell body, dendrites, axon, and axon terminals

  
• The spinal cord is a long, thin, cylindrical bundle of nerves that runs from the brain down the spinal column, responsible for sending messages between the brain and the rest of the body

  
• The autonomic nervous system is a division of the peripheral nervous system that innervates involuntary muscles, glands, and organs, divided into the sympathetic nervous system and the parasympathetic nervous system
• The sympathetic nervous system is responsible for the body's "fight or flight" response, while the parasympathetic nervous system is responsible for the body's "rest and digest" response
• A neuromuscular junction is a synapse between a motor neuron and a muscle fiber, where acetylcholine is released to cause muscle contraction

  
• The Tensilon test is used to diagnose myasthenia gravis by injecting Tensilon, which blocks the action of acetylcholine, improving symptoms if the patient has myasthenia gravis

  
• The regulation of heart rate involves the SA node sending electrical impulses to the AV node, with the vagus nerve slowing down the heart rate by releasing acetylcholine

  
• Parietal cells in the stomach produce hydrochloric acid necessary for digestion, involving different receptors and hormones in the process

  
• Non-depolarizing muscle relaxants block acetylcholine receptors on the motor end-plate, resulting in skeletal muscle relaxation and respiratory paralysis

  
• The stretch reflex is illustrated

  
• A neuron is the basic functional unit of the nervous system, responsible for receiving and transmitting signals to different parts of the body

  
• The autonomic nervous system is divided into the sympathetic nervous system (responsible for the "fight or flight" response) and the parasympathetic nervous system (responsible for the "rest and digest" response)

  
• The kidneys are responsible for filtering waste products from the blood and producing urine, while the adrenal glands produce hormones that help regulate the body's response to stress

  
• At the neuromuscular junction, the motor neuron releases acetylcholine, which binds to receptors on the muscle fiber, causing it to contract; acetylcholinesterase breaks down acetylcholine, terminating the contraction

  
• The Tensilon test is used to diagnose myasthenia gravis; if a patient's symptoms improve after taking Tensilon, it is likely that they have the disorder

  
• The regulation of heart rate involves the SA node, AV node, and the vagus nerve releasing acetylcholine to slow down the heart rate; atropine, a competitive antagonist of acetylcholine, can lead to an increased heart rate

  
• Parietal cells in the stomach produce hydrochloric acid necessary for food digestion, involving different receptors and hormones in the process

  
• Non-depolarizing muscle relaxants block acetylcholine receptors on the motor end-plate, preventing muscle cell depolarization and contraction, resulting in skeletal muscle relaxation and respiratory paralysis

  
• The autonomic nervous system is divided into the sympathetic nervous system (responsible for the body's "fight or flight" response) and the parasympathetic nervous system (responsible for the body's "rest and digest" response)

  
• The Tensilon test is used to diagnose myasthenia gravis by injecting a drug that blocks the action of acetylcholine, improving symptoms if the patient has the condition

  
• The regulation of heart rate involves the SA node sending electrical impulses to the AV node, which then sends them to the heart's ventricles, causing them to contract and pump blood

  
• Non-depolarizing muscle relaxants block acetylcholine receptors on the motor end-plate, preventing muscle cell depolarization and contraction, leading to skeletal muscle relaxation and respiratory paralysis

  
• Excessive VMA in urine can indicate high catecholamine levels, possibly due to a tumor in the adrenal medulla

  
• A neuron is the basic functional unit of the nervous system, receiving and transmitting signals to different parts of the body

  
• The spinal cord is a long, thin, cylindrical bundle of nerves responsible for sending messages between the brain and the rest of the body

  
• The autonomic nervous system innervates involuntary muscles, glands, and organs, divided into the sympathetic nervous system ("fight or flight" response) and the parasympathetic nervous system ("rest and digest" response)

  
• The kidneys filter waste products from the blood and produce urine, while the adrenal glands produce hormones regulating the body's stress response

  
• A neuromuscular junction is a synapse between a motor neuron and a muscle fiber, where acetylcholine causes muscle contraction and acetylcholinesterase inhibitors can increase muscle contraction, used in conditions like myasthenia gravis

  
• The Tensilon test, using a drug to block acetylcholine action, is used to diagnose myasthenia gravis

  
• Parietal cells in the stomach produce hydrochloric acid necessary for food digestion

  
• Nicotinic effects:

  • Act predominantly on GIT, UB
  • Nicotinic actions > Muscarinic actions
  • Used in conditions like glaucoma, to stimulate micturition, reduce headache in migraine patients
• Bethanechol (Urecholine®):

  • Acts predominantly on GIT, UB
  • Increases intestinal motility and relaxes the bladder sphincter to stimulate urination
  • Uses include treatment of gastric retention, postoperative abdominal distention, nonobstructive urinary retention, and prevention of paralytic ileus
• Pilocarpine:

  • Acts similarly to ACh
  • Used with carbachol to treat glaucoma by stimulating M3 in the pupil for miosis and decreased ocular pressure
• Nicotine:

  • Component of cigarette smoke
  • Brain effects include mood boost, reduced depression, irritability, and appetite, with acute toxicity at 40mg
  • Chronic toxicity from smoking can lead to dangerous effects like convulsions, coma, and respiratory arrest
• Indirect acting agonists:

  • Increase acetylcholine in the synaptic cleft by inhibiting acetylcholinesterase
  • Produce primary effects by inhibiting acetylcholinesterase, increasing ACh concentration at cholinoreceptors
• Reversible inhibitors:

  • Attach to the ACHE enzyme and are slowly hydrolyzed
  • Examples include edrophonium (Tensilon®) for diagnosing myasthenia gravis
• Irreversible inhibitors:

  • React to form a stable, phosphorylated enzyme, persisting effects until new enzyme synthesis
  • Highly toxic, with organophosphates being examples
• The kidneys filter waste products from the blood and produce urine, while the adrenal glands produce hormones regulating the body's response to stress

  
• The Tensilon test, using a drug called Tensilon, is used to diagnose myasthenia gravis by blocking the action of acetylcholine involved in muscle contraction

  
• The regulation of heart rate involves the SA node, AV node, and the vagus nerve releasing acetylcholine to slow down the heart rate