Communication

Question 1

What is a neuromuscular junction?

Answer 1

-a specialised structure incorporating axon terminal & muscle membrane allowing unidirectional chemical communication between peripheral nerve & muscle.

Question 2

What type of communication is between nerve and effector cells?

Answer 2

Paracrine

Question 3

How does a neuromuscular junction work?

Answer 3

Neuromuscular junction:
• Action potential propagated along axon (Na+ & K+) → Ca2+ entry at presynaptic terminal
• Ca2+ entry → acetylcholine (ACh) release into synpase
• ACh binds to nicotinic ACh receptors (nAChR) on skeletal muscle→change in end-plate potential (EPP)
(• Miniature EPP: quantal ACh release)

Question 4

What are T-tubules?

Answer 4

• continuous with sarcolemma & closely connected to sarcoplasmic reticulum
• action potentials travel through T-tubules

Question 5

Tell me about the sarcoplasmic reticulum.

Answer 5

• surrounds myofibrils (contractile units of muscle)
• used for Ca storage, which is related following sarcolemma depolarisation
• Ca release causes myofibril & muscle contraction

Question 6

What is Botulism?

Answer 6

-Botulinum toxin (BTx): irreversibly disrupts stimulation-induced ACh release from presynaptic nerve terminal

Question 7

What is Myasthenia Travis (MG)

Answer 7

• autoimmune disorder: Abs directed against Each receptor

- cause fatigable weakness (i.e becomes more pronounced with repetitive use)

Question 8

What is Lambert-Eaton myastenic syndrome (LEMS)?

Answer 8

-autoimmune disorder: antibodies directed against VGCC

Question 9

lecture slides

Answer 9

https://imperiallondon-my.sharepoint.com/personal/jmoss1_ic_ac_uk/Documents/Bioregulatory%20Systems/01.%20Neurology%20%26%20neuroscience/Student%20resources/Neuro_LE02_Cells_of_the_nervous_system_and_neuromuscular_junction.pdf?&originalPath=aHR0cHM6Ly9pbXBlcmlhbGxvbmRvbi1teS5zaGFyZXBvaW50LmNvbS86YjovZy9wZXJzb25hbC9qbW9zczFfaWNfYWNfdWsvRWZ1SmdzTFR2ZUZBc1czVVI4RTdaRzhCeW85MFdCM19fbVJSOV9MckZ0djJqZz9ydGltZT1yOFRMZmJHTTEwZw