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23 year old male patient infected with Tetanospasmin "Tetanus…
23 year old male patient infected with Tetanospasmin "Tetanus toxin"
background information
anatomy
organ systems
peripheral nervous system
respiratory system
central nervous system
muscular system
lymphatic system
neurons
motor neurons (efferent neurons)
sensory neurons (afferent neurons)
integrating neurons (interneurons)
excitatory postsynaptic potentials (EPSPs)
excitatory neurotransmitters
sodium chemically-gated ion channel
inhibitory postsynaptic potentials(IPSPs)
inhibitory neurotransmitters
chloride chemically-gated ion channel
potassium chemically-gated ion channel
Clostridium tetani
physiology
organ system functions
PNS-consists of nerves and ganglia outside the spinal cord. It connects the CNS to the limbs and organs
respiratory system- does gas exchange
CNS- Consists of the brain and spinal cord, responsible for integrating sensory information and responding accordingly
muscular system- supports movement, helps maintain posture, and circulate blood throughout the body
lymphatic system- network of tissues and organs that help rid the body of toxins. It transports lymph, a fluid containing infection-fighting white blood cells throughout the body
neuron functions
moter- carry impulses away from the CNS to effectors like muscles, organs, and glands
sensory- transmit impulses from sensory receptors in the skin or organs toward the CNS
integrating-conduct impulses within the CNS and integrate incoming sensory input to predict the proper motor output
EPSPs functions
excitatory neurotransmitters bind to and open the sodium chemically-gated ion channels
excitatory neurotransmitters open channels that depolarize the membrane
IPSPs functions
inhibitory neurotransmitters bind to an open the potasium and chloride channels
inhibitory neurotransmitters open channels that hyperpolarize the membrane
Clostridium tetani
releases the toxin Tetanospasmin "tetanus toxin" and is responsible for the symptoms of tetanus
Tetanospasmin spreads via the lymphatic system and bloodstream throughout the body where it is then taken up into various parts of the nervous system
Tetanospasmin acts by blocking the release of inhibitory neurotransmitters glycine and gamme-aminobutyric acid at motor nerve endings
this then leads to a widespread activation of motor neurons and spasming of muscles through out the body
excitation-contraction coupling
step 6- myosin heads form cross bridges to the actin and pivot toward the M line causing chemically activated muscle contraction
step 7- ATP binds to the myosin heads, causing them to release muscle contraction and recock
step 5- the movement of Ca2+ into the muscle cell causes Ca2+ to bind to troponin, which moves tropomyosin, exposing the myosin-binding active sites
step 4- this causes depolarization of the T tubules and causes the release of Ca2+ from the terminal of the SR
step 3- ACh then binds to receptors on the motor end plate, if the end plate reaches threshold(-55) an action potential is propagated on the sarcolemma and down the T tubeles
step 2-influx of Ca2+ causes the exocytosis of ACh into the synaptic cleft
step 1- an action potential arrives at the axon terminal and voltage-gated Ca2+ channels open causing an influx of Ca2+ into the axon terminal
Summation
temporal
a rapidly firing presynaptic neuron causes EPSPs that are close in time
two EPSPs close in time add together
summation brings the axons initial segment to threshold and AP fires
spatial
twp EPSPs at the same time from different locations add together
summation brings the axons initial segment to threshold and an AP fires
when more than one presynaptic neuron fires at the same time. EPSPs are generated at different locations of the neuron
UPSTREAM CAUSES
DIRECT CAUSE- tetanus neurotoxin binds to the presynaptic membrane of the neuromuscular junction, its internalized and transported to the spinal cord. The spasms are due to the blockade of neurotransmitter release from spinal inhibitory interneurons
INDIRECT CAUSE- the patient did a couple of things that led him to contracting tectanus
he was never vaccinated and got his tetanus shot
he went to a sketchy tattoo parlor that most likely had the dirty needles that infected him. You should always make sure the environment is clean and needles are new, never used.
DOWNSTREAM CAUSES
if this toxin remains in the bloodstream the following could happen
CNS
Brain damage can happen due to the lack of oxygen
cardiovascular
abnormal heart rhythm and eventually heart attack
respiratory system
breathing problems due to spasms of vocal cords and spasms of the muscles that control breathing
pneumonia
muscular and skeletal
many bone fractures and fractures of the spine due to muscle spasms and convulsions
there could also be secondary infections developed due to prolonged hospital stays
Ultimately if this toxin remains in the bloodstream untreated the patient will die