Physiology of Vomiting - Vomiting reflex (NEW)
Summary
TLDRThis video delves into the physiology of vomiting, also known as emesis. It explains the involuntary process as the forceful expulsion of stomach contents through the mouth, triggered by the vomiting reflex. The medulla oblongata in the brainstem houses the vomiting center, which initiates the reflex upon stimulation by muscarinic receptors. The chemoreceptor trigger zone (CTZ), located outside the blood-brain barrier, is sensitive to chemicals like those in chemotherapy and motion sickness. It interacts with the vomiting center to induce vomiting. The video also covers the role of the vestibular system in motion sickness and how higher brain centers respond to emotional states and sensory inputs to trigger vomiting. Finally, it outlines the physiological changes during vomiting, including muscle contractions and autonomic responses.
Takeaways
- ๐คฎ Vomiting, also known as emesis or throwing up, is an involuntary, forceful expulsion of stomach contents through the mouth.
- ๐ง The vomiting reflex is controlled by the vomiting center located in the medulla oblongata of the brainstem, which contains muscarinic receptors.
- ๐งช The chemoreceptor trigger zone (CTZ), situated outside the blood-brain barrier, is sensitive to chemicals and can be stimulated by drugs like those used in chemotherapy.
- ๐ซ The blood-brain barrier protects the brain from circulating substances, but the CTZ's location outside this barrier makes it more susceptible to such substances.
- ๐ Motion sickness, caused by the inner ear's vestibular system, can stimulate the CTZ, leading to the vomiting reflex.
- ๐คฐ Morning sickness is another condition that can trigger the vomiting reflex, often due to hormonal changes during pregnancy.
- ๐คข The cerebrum can also initiate vomiting through the vomiting center when processing sensory information related to strong smells or sights.
- ๐ The stomach's enterochromaffin cells release serotonin in response to cytotoxic agents, which can trigger the vomiting reflex via the vagal nerve.
- ๐ The vomiting reflex involves the relaxation of the lower esophageal sphincter, contraction of the diaphragm and abdominal muscles, and closure of the epiglottis to prevent aspiration.
- ๐คง Autonomic changes during vomiting include increased heart rate, salivation, and peristalsis, which all contribute to the forceful expulsion of stomach contents.
Q & A
What is vomiting also known as?
-Vomiting is also known as emesis and throwing up, amongst many other terms.
What is the involuntary forceful expulsion of stomach contents through the mouth called?
-The involuntary forceful expulsion of stomach contents through the mouth is called the emetic reflex or the vomiting reflex.
Where is the vomiting center located in the brain?
-The vomiting center is located in the medulla oblongata of the brainstem.
What types of receptors are found in the vomiting center?
-The vomiting center contains muscarinic receptors.
What is the chemo receptor trigger zone (CTZ) and where is it located?
-The chemo receptor trigger zone (CTZ) is an area near the medulla oblongata that gets triggered by chemicals and is located outside the blood-brain barrier.
Which receptors are found in the chemo receptor trigger zone (CTZ)?
-The CTZ contains dopamine 2 receptors and 5-HT receptors, which are serotonin receptors.
How does motion sickness relate to the vomiting reflex?
-Motion sickness, which originates from the inner ear's Labyrinth, can stimulate the vestibular nuclei, which then sends signals to the CTZ, leading to the vomiting reflex.
What is the role of the higher brain centers in initiating the vomiting reflex?
-The higher brain centers can sense emotional overwhelm, severe pain, bad smells, or repulsive sights and send signals to the vomiting center to initiate the vomiting reflex.
How do interoceptive cells in the stomach contribute to the vomiting reflex?
-Interoceptive cells in the stomach release serotonin in response to cytotoxic agents, which can stimulate 5-HT3 receptors on sensory nerve fibers, leading to the activation of the vomiting center.
What happens during the vomiting reflex that facilitates the expulsion of stomach contents?
-During the vomiting reflex, the lower esophageal sphincter relaxes, the diaphragm and abdominal muscles contract to increase intra-abdominal pressure, and the epiglottis closes to prevent food from entering the lungs.
What autonomic changes occur during the vomiting reflex?
-Autonomic changes during the vomiting reflex include an increase in heart rate (tachycardia), increased salivation, and peristalsis.
Outlines
๐คฎ Understanding Vomiting Reflex
This paragraph delves into the physiology of vomiting, also known as emesis or throwing up. It explains the involuntary forceful expulsion of stomach contents through the mouth. The emetic reflex, or vomiting reflex, is controlled by the medulla oblongata in the brainstem, which contains the vomiting center with muscarinic receptors. These receptors, when stimulated, trigger the vomiting reflex. The chemoreceptor trigger zone (CTZ), located near the medulla oblongata but outside the blood-brain barrier, is sensitive to chemicals like those found in chemotherapy and motion sickness. The CTZ, when stimulated, activates the muscarinic receptors in the vomiting center. The paragraph also discusses how the vestibular nuclei, which contain histamine and muscarinic receptors, can be stimulated by the inner ear's Labyrinth, leading to motion sickness and vomiting. Lastly, it mentions how higher brain centers can initiate the vomiting reflex in response to emotional, olfactory, or visual stimuli.
๐ Anatomy and Physiology of Vomiting
The second paragraph recaps the anatomy involved in vomiting, starting from the mouth down to the stomach and small intestine. It highlights the role of Intero chromin cells in the stomach, which release serotonin in response to cytotoxic agents, potentially stimulating 5-HT3 receptors on sensory nerve fibers. This stimulation, via the vagal nerve, communicates with the vomiting center to trigger the vomiting reflex. The paragraph summarizes that all causes of vomiting stimulate the vomiting center, leading to the emetic reflex. It then describes the process of vomiting, which includes the relaxation of the lower esophageal sphincter, contraction of the diaphragm and abdominal muscles to increase intra-abdominal pressure, and autonomic changes like increased heart rate and salivation. The vomiting reflex also causes the epiglottis to close to prevent food from entering the lungs, culminating in the expulsion of food.
Mindmap
Keywords
๐กVomiting
๐กEmetic Reflex
๐กMedulla Oblongata
๐กChemoreceptor Trigger Zone (CTZ)
๐กBlood-Brain Barrier
๐กLabyrinth
๐กVestibular Nuclei
๐กCerebrum
๐กInteroceptive Cells
๐กVagal Nerve
Highlights
Vomiting, also known as emesis, is an involuntary forceful expulsion of stomach contents through the mouth.
The emetic reflex, or vomiting reflex, is a key mechanism in understanding vomiting.
The medulla oblongata in the brainstem houses the vomiting center, which initiates the vomiting reflex.
The vomiting center contains muscarinic receptors that, when stimulated, trigger vomiting.
The chemo receptor trigger zone (CTZ) is located near the medulla oblongata and is sensitive to chemicals.
The CTZ contains dopamine 2 and 5-HT (serotonin) receptors, which can be stimulated by various substances.
Chemotherapy, which stimulates the CTZ, is a common cause of vomiting due to its chemical nature.
Motion sickness, caused by the inner ear's Labyrinth, can trigger the vomiting reflex via the vestibular nuclei.
The vestibular nuclei, containing histamine and muscarinic receptors, play a role in balance and vomiting.
Emotional states, severe pain, and repulsive sights or smells can cause vomiting by stimulating the higher brain centers.
The stomach's Intero chromin cells release serotonin in response to cytotoxic agents, potentially triggering vomiting.
The vomiting reflex involves the relaxation of the lower esophageal sphincter to allow food to move upwards.
Contraction of the diaphragm and abdominal muscles increases intra-abdominal pressure, aiding in vomiting.
Autonomic changes such as tachycardia, increased salivation, and peristalsis occur during vomiting.
The epiglottis closes during vomiting to prevent food from entering the lungs.
All causes of vomiting essentially stimulate the vomiting center, initiating the emetic reflex.
The process of vomiting involves a complex interplay of physiological mechanisms to expel stomach contents.
Transcripts
hello in this video we're going to talk
about the physiology of vomiting now
vomiting is also known as emesis and
throwing up amongst many other terms and
it is a involuntary forceful expulsion
of the contents of one's stomach
essentially through the mouth we will
look at the so-called emetic reflex
which is the vomiting reflex and in
order to understand the vomiting reflex
we need to talk about the brain so here
is the brain and the brain stem there's
an area of the brain stem called the
medulla oblongata where we find What's
called the vomiting
Center the vomiting Center contains
essentially muscarinic receptors types
of receptors and when these receptors
are stimulated within the vomiting
Center this will trigger the vomiting
reflex so the process of vomiting
close to the vomiting Center also near
the mola oblongata of the brain stem is
another area called the chemo receptor
trigger zone or ctz for
short now the ctz as the name suggests
gets triggered by
chemicals and the ctz contains a few
types of receptors and these are the
dopamine 2 receptors and the 5 HT
receptors 5ht essentially is serotonin
so these are serotonin
receptors it's easy to remember ctz
because we know that
chemotherapy stimulates this chemo
receptor trigger zone so when the chemo
receptor triggers Z the ctz is
stimulated it will then stimulate the
muscarinic receptors of the vomiting
Center and when the muscarinic receptors
of the vomiting Center are stimulated
this this will cause the vomiting reflex
the Ematic
reflex though the chema receptor trigger
zone is located in the medulla like the
vomiting Center the chemo receptor
trigger zone is located conveniently
outside the blood brain barrier now the
blood brain barrier is a barrier
preventing circulating substances in the
blood from making contact with the brain
um and areas of the brain stem because
the chemo receptor trigger zone is
situated outside the blood brain barrier
it is thus more permeable to circulating
substances such as cytotoxic agents
chemotherapy motion sickness is a very
common thing people experience and the
cause of motion sickness actually comes
from the inner ear a bony structure
called The
Labyrinth the Labyrinth is made up of
many areas one of which is called the
the Tibu a structure important for
balance in
space problems here will send electrical
signals to the brain stem via the
vestibular ccka nerve and the signals
will get sent to an area specifically in
the brain stem called the vestibular
nuclei which is located in the ponds of
the brain
stem the vestibular nuclei contain
histamine one receptors
and also muscarinic
receptors so when the vestibular nuclei
is stimulated during let's just say
motion
sickness or during also morning
sickness these signals will then be
passed on to the chemo receptor trigger
Zone and from here the chemo receptor
trigger Zone will then send signals to
the vomiting Center in the mola
oblongata to trigger the vomiting reflex
another cause of vomiting are things
that occur from the cerebrum or the
brain after it has processed all this
sensory information so what I mean is
that for example when people are
emotionally
overwhelmed or when people are in severe
pain or when they smell something really
bad or they see something repulsive
something really bad essentially all
this stuff will get sensed by the brain
by the higher centers of the brain and
from the higher brain centers this will
then this this signal then travel down
to the vomiting Center to stimulate the
vomiting Center to initiate the vomiting
reflex this makes sense because some
people get really nauseous when they see
blood or guts or they smell something
like a type of food that just smells
horrible again the higher brain centers
stimulate the vomiting Center through
muscarinic
receptors other causes of vomiting occur
in the stomach so let's just recap some
Anatomy here so we have the mouth which
connects to the esophagus which will
travel down through the diaphragm which
is the muscle muscular structure the
esophagus will then join onto the
stomach and then the stomach joins onto
the small
intestin if we were to zoom into the
stomach we can see they form deep pits
deep pits and glands and these are lined
up by many different types of cells one
of which are called Intero chromin
cells the Intero chromin cells release
serotonin in response to cytotoxic
agents which is ALS which is thought to
stimulate then um five ht3 receptors on
sensory nerve fibers around the area
and stimulation of this sensory nerve
fiber which is actually the vagal nerve
will bring this information to the
vomiting Center to trigger the vomiting
reflex in summary all the causes of
vomiting we talked about essentially
will stimulate the vomiting Center which
is the output from which the vomiting
reflex or the emetic reflex is
initiated let's focus on what the
vomiting reflex is and actually what
happens during the
process first it actually causes the
lower esophagal sphincter to relax which
makes sense because we need food to come
up towards the mouth when we
vomit we also need the diaphragm to
contract and also the abdominal muscles
to contract so that it will help push
the food back up and this happens
because we are increasing intraabdominal
pressure when we contct our
muscles there are also autonomic changes
such as tadia which is increase in heart
rate and we also increase salvation as
well as
peristalsis the vomiting reflex also
causes the epiglottis to close on um at
the top part because we don't want food
to travel down to the
lungs and once the vomiting reflex does
all these things then the vomit or the
food exposion of food can
happen so that was the physiology of
vomiting The emetic Reflex the vomiting
reflex
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