Patient was experiencing severe face and arm muscle spasms and can hardly speak. We notice patient also has a fresh tattoo that he got the day before. After running blood tests, it turns out he is infected with Clostridium tetani, which is a bacterium that is found in soil and can be transmitted by using dirty needles. We also found out he has never been vaccinated against this bacterium.
this poison spreads to the central nervous system
it binds to the presynaptic membrane of the neuromuscular junction and transports to the spinal cord
the toxin blocks the nerve signals from your spinal cord to your muscles which leads to severe, painful, muscle spasms or contractions
What patient did not do was get the vaccination to prevent this bacterium
He also went to a "sketchy" tattoo shop which he should have went to a place that had a sterilized environment and didn't seem "sketchy"
Clostridium tetani causes tetanus
spores of the bacterium can be found in dust, dirt, and animal feces
a person can get infected if these spores enter through a cut or deep wound
they produce a toxin called tetanospasmin
nervous system
respiratory system
muscular system
cardiovascular system
receives and interprets stimuli and transports impulses
helps with movement and posture,
movement is enabled by skeletal muscles which are controled by motor neurons
pumps blood through out the body
if affected by tetanus
the heart
blood vessels
spores can produce living tetanus bacteria and also release a toxin called tetanospasmin which then enters the blood stream
normal function when sending messages:
electrical message is sent down the axon of a motor neuron and arrives at the axon terminal
neurotransmitters are released which bind to the muscle fibers causing them to contract
shortly after, the neurotransmitters are released from the muscle fibers which will allow them to relax
but if affected by tetanus:
the bacteria can reach motor neurons by the blood stream
bacteria enters the blood stream, which then effect the motor neurons and causes uncontrollable contractions
after 2-14 days, the toxin reaches the motor neuron cell body in the spinal cord
normally, the motor neurons in the spinal cord are controlled by inhibitory interneurons
the interneurons prevent the motor neurons from constantly firing
but as the toxins arrive in the motor neuron cell body, the toxins interfere with the action of the inhibitory interneurons
interneurons release inhibitory neurotransmitters into the synaptic junction
which prevents firing of motor neurons so that the muscle fibers are controlled and do not constantly contract
tetanospasmin moves out of the motor neurons across the synaptic into the inhibitory interneurons
this toxin prevents the release of inhibitory neurotransmitters from the interneuron
which then causes the interneuron to no longer control the motor neuron
the motor neuron fires constantly and uncontrollably
this leads to continual release of neurotransmitters from the motor neuron terminal
causes the muscle fibers to contract repeatedly until spasm occurs
which can also lead to lockjaw
a highly reduced ability to open the mouth
attempting to open the mouth may induce spasms that cause the complete clenching of the jaw
if not treated, this could lead to death
can cause abnormal heart rhythm
if tetanus is not treated, it can lead to death
exchange of gases
if affected by tetanus
muscle spasms can interfere with breathing
cause lack of oxygen
which can induce cardiac arrest
which can lead to death
respiratory failure is the most common cause of death
normal function of these organ systems
nervous system
receives and interprets stimuli and transports impulses
electrical message is sent down the axon of a motor neuron and arrives at the axon terminal
neurotransmitters are released which bind to the muscle fibers causing them to contract
shortly after, the neurotransmitters are released from the muscle fibers which will allow them to relax
muscular system
helps with movement and posture,
cardiovascular system
pumps blood through out the body
respiratory system
exchange of gases
neurons
structural classification
functional classification
bipolar
unipolar
multipolar
neurons with multiple extensions from the cell body
allows for the integration of a great deal of information from other neurons
located in the central nervous system
most abundant in the body
neurons with one extension off of their cell body
often found in the dorsal root ganglia of the spinal cord
sensory neurons
In addition to pain and touch, they also carry information about temperature, taste, proprioception
neurons with two extensions from the cell body
found in special sensory neurons, such as the retina of the eye
they are part of the sensory pathways for smell, sight, taste, hearing, touch, and balance
interneuron
motor neuron
sensory neuron
transmit impulses from sensory receptors in the skin or organs TOWARDS the central nervous system
unipolar
conduct impulses WITHIN the central nervous system and integrate incoming sensory input to predict the proper output
carry impulses AWAY from the central nervous system effectors, such as muscles, organs, or glands
multipolar
Excitation Contraction Coupling
the sequence of events that converts action potentials in a muscle fiber to a contraction
at the neuromuscular junction, a motor neuron releases acetylcholine (ACh)
ACh attaches to chemically gated sodium channels on the sarcolemma
the sarcolemma (membrane) of a muscle fiber depolarizes and causes voltage gated sodium channels to open
the action potential travels across the sarcolemma because of voltage gated sodium channels channels
then voltage gated calcium channels open
calcium then binds to troponin
tropomyosin unblocks the myosin binding sites on actin
myosin attaches to and slides past actin
this is where the neurotransmitter is released at +30
troponin keeps tropomyosin in place but can be bumped out of place by the ion calcium
tropomyosin covers the myosin binding sites on actin which causes myosin to not be exposed
this is where the muscle contraction happens
summation
this is the process that occurs when a neuron uses more than one message to determine if it should depolarize
neurotransmitters
EPSPs are called excitatory neurotransmitters
these neurotransmitters open channels that depolarize the membrane
temporal summation
spatial summation
a rapidly firing presynaptic neuron causes EPSPs that are close in time
two EPSPs close in time add together (temporal=time)
summation brings the axon's initial segment to threshold and AP fires
neurons constantly receive messages
they "add" the message together
the electrical "sum" of those messages predicts whether or not the neuron depolarizes
the magic number that the sum reaches is -55mV
basically its one neuron sending a bunch of messages
if more than one presynaptic neuron fires at the same time, EPSPs are generated at different locations on the neuron
two EPSPs at the same time from different locations add together (spatial=location)
summation brings the axon's initial segment to threshold and AP fires
threshold equals -55
basically this is when multiple messages are coming in from multiple neurons
of EPSPs and IPSPs
if a presynaptic neuron creates an IPSP, it can override the EPSP created by another neuron
an EPSP brings the neuron closer to threshold
an IPSP brings the neuron farther from the threshold
together, they (nearly) cancel each other out
hyperpolarization and depolarization
become more positive
IPSPs called inhibitory neurotransmitters
these neurotransmitters open channels that hyperpolarize the membrane
become more negative
potassium channels
chloride channels
sodium channels
tetanus affecting the neuromuscular junction
tetanus neurotoxins (Clostridium tetani) bind to the presynaptic membrane of a neuromuscular junction
it then is internalized and transported to the spinal cord
which then blocks neurotransmitter release from spinal inhibitory interneurons
this causes uncontrollable spasms