Neuromuscular Junction (NMJ) (The chain of events that normally occur at…
Neuromuscular Junction (NMJ)
23 year old patient is infected with Clostridium tetani, a common bacterium found in soil that can be transmitted by using dirty needles
Integumentary system: comprises the skin and its appendages acting to protect the body from various kinds of damage, such as loss of water or damages from outside
Nervous system: coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes that impact the body
Muscular system: consisting of skeletal, smooth and cardiac muscles. It permits movement of the body, maintains posture and circulates blood throughout the body
lymphatic system: immune system, composed of a large network of lymphatic vessels that carry a clear fluid called lymph directionally towards the heart
The chain of events that normally occur at the neuromuscular junction
action potential (AP) comes from central nervous system and arrives at axon terminal of motor neuron
voltage-gated Ca2+ channels open. Ca2+ enters axon, moving down electrochemical gradient
Ca2+ entry causes ACh to be released by exocytosis
ACh diffuses across synaptic cleft and binds to its receptors on sarcolemma
ACh binding opens ion channels that allows simultaneous passage of Na+ into muscle fibers and K+ out of muscle fibers. More Na+ ions enter than K+ ions exit, which produces change in membrane potential called "end plate potential"
ACh effects are terminated by its breakdown in synaptic cleft by acetylcholinesterase and diffusion away from junction
Neurotransmitters involved in triggering muscle contraction
Acetylcholine: the chemical message, a neurotransmitter called acetylcholine, binds to receptors on the outside of the muscle fiber. That starts a chemical reaction within the muscle.
Calcium (Ca2+ ): the endoplasmic reticulum (ER), and, in muscle cells, the sarcoplasmic reticulum (SR). The low [Ca2+]c is maintained through the action of the plasma membrane Ca2+ transport ATPase (PMCA) and the Na+/Ca2+ exchanger (NCX) in a resting cell
The steps involved in exocytosis
A nerve signal is propagated down a motor axon and triggers the entry of Ca2+ into the synaptic knob
Calcium binding triggers synaptic vesicles sites to merge with the synaptic knob plasma membrane and ACh is exocytosed into the synaptic cleft
ACh diffuses across the fluid-filled synaptic cleft at the motor end plate to bind with ACh receptors
The difference between a twitch, summation, and tetany.
Twitch: a brief contractions period and relaxation period of a skeletal muscle in response to a single stimulation
Summation: successive stimuli are added together to produce a stronger muscle contraction.
Tetany: tetanic seizure is a medical sign consisting of the involuntary contraction of muscles, which may be caused by disorders that increase the action potential frequency of muscle cells or the nerves that innervate them.
Penetrating the skin causes skin infections and other complications are possible, including: Allergic reactions
Rash or red, bumpy skin around the area where the tattoo is
Swelling of the tattooed area. pus coming out of the tattooed area
atypical mycobacterial infection
contaminated ink or ink that is diluted with unsterilized water can lead to an infection.