The process of neurulation drives development of the system we use to help understand and interact with the world around us. Sometimes this process might stray from its chosen path due to internal/external factors, leading to unusual pathologies. Understanding neurulation can help us work out how things go wrong.
about 7 years ago
Four Major Lober Diencephalon - Homeostasis Brain stem - Relay Station Limic System - Memory and Emotion Image: https://docs.google.com/open?id=0B8Ss3-wJfHrpejFtSkdLWHlNdWs Facebook: http://www.facebook.com/home.php#!/ArmandoHasudungan
over 6 years ago
Can you imagine being able to search for locations in the human body in the same way you can on Google Maps? This thinking lead Programmer Rich Stoner to create this amazing video of a 21st Century Map of the Brain which was our most popular tweet last week. A 21st Century Map of the Brain http://t.co/tkojzJBW55 via @brianglanz #openscience— Meducation (@Meducation) October 18, 2013 Rich writes in his blog - “Now we can quickly search Google Maps for a location, ask what is nearby, and even see what it looks like using StreetView. Now, imagine if something like that existed for the human brain: an interactive environment to search, visualize, and explore layers upon layers of neuroanatomy. This is the dream of cortical cartographers (also known as neuroanatomists). 10 years ago, one of the largest brain mapping initiatives was founded by Paul Allen with a single goal: to build a 21st Century Map of the Brain.” Click here to read more. The mapping of the brain is a working progress and therefore not 100% accurate. Even so the video gives us an insight into the innovate ways we will be able to interact with science in the future. You can follow Meducation on twitter to see more tweets like this at twitter.com/meducation.
over 6 years ago
Use mind maps to discover and develop your understanding of Occupational Therapy - this visual resource for OT students uses mindmeister to organise concepts.
about 5 years ago
Great people make mistakes. Unfortunately, medicine is a subject where mistakes are not tolerated. Doctors are supposed to be infallible; or, at least, that is the present dogma. Medical students regularly fall victim to expecting too much of themselves, but this is perhaps not a bad trait when enlisting as a doctor. If it weren’t for mistakes in our understanding, then we wouldn’t progress. Studying a BSc in Anatomy has exposed me to the real world of science – where the negative is just as important as the positive. What isn’t there is just as important as what is. If you look into the history of Anatomy, it truly is a comedy of errors. So, here are three top mistakes by three incredibly influential figures who still managed to be remembered for the right reasons. 3. A Fiery Stare Culprit: Alcmaeon of Croton Go back far enough and you’ll bump into someone called Alcmaeon. Around the 5th century, he was one of the first dissectors – but not an anatomist. Alcmaeon was concerned with human intellect and was desperately searching for the seat of the soul. He made a number of major errors - quite understandable for his time! Alcmaeon insisted that sleep occurs when the blood vessels filled and we wake when they empty. Perhaps the most outrageous today is the fact that he insisted the eyes contained water both fire and water… Don’t be quick to mock. Alcmaeon identified the optic tract, the brain as the seat of the mind (along with Herophilus) and the Eustachian tubes. 2. Heart to Heart Culprit: Claudius Galen Legend has it that Galen’s father had a dream in which an angel/deity visited him and told him that his son would be a great physician. That would have to make for a pretty impressive opening line in a personal statement by today’s standards. Galen was highly influential on modern day medicine and his treatise of Anatomy and healing lasted for over a thousand years. Many of Galen’s mistakes were due to his dissections of animals rather than humans. Unfortunately, dissection was banned in Galen’s day and where his job as physician to the gladiators provided some nice exposed viscera to study, it did not allow him to develop a solid foundation. Galen’s biggest mistake lay in the circulation. He was convinced that blood flowed in a back and forth, ebb-like motion between the chambers of the heart and that it was burnt by muscle for fuel. Many years later, great physician William Harvey proposed our modern understanding of circulation. 1. The Da Vinci Code Culprit: Leonardo Da Vinci If you had chance to see the Royal Collection’s latest exhibition then you were in for a treat. It showcased the somewhat overlooked anatomical sketches of Leonardo Da Vinci. A man renowned for his intelligence and creativity, Da Vinci also turns out to be a pretty impressive anatomist. In his sketches he produces some of the most advanced 3D representations of the human skeleton, muscles and various organs. One theory of his is, however, perplexing. In his sketches is a diagram of the spinal cord……linked to penis. That’s right, Da Vinci was convinced the two were connected (no sexist comments please) and that semen production occurred inside the brain and spinal cord, being stored and released at will. He can be forgiven for the fact that he remarkably corrected himself some years later. His contributions to human physiology are astounding for their time including identification of a ‘hierarchal’ nervous system, the concept of equal ‘inheritence’ and identification of the retina as a ‘light sensing organ’. The list of errors is endless. However, they’re not really errors. They’re signposts that people were thinking. All great people fail, otherwise they wouldn’t be great.
over 6 years ago
Cranial Nerve 1- Olfaction This patient has difficulty identifying the smells presented. Loss of smell is anosmia. The most common cause is a cold (as in this patient) or nasal allergies. Other causes include trauma or a meningioma affecting the olfactory tracts. Anosmia is also seen in Kallman syndrome because of agenesis of the olfactory bulbs. Cranial Nerve 2- Visual acuity This patientâs visual acuity is being tested with a Rosenbaum chart. First the left eye is tested, then the right eye. He is tested with his glasses on so this represents corrected visual acuity. He has 20/70 vision in the left eye and 20/40 in the right. His decreased visual acuity is from optic nerve damage. Cranial Nerve II- Visual field The patient's visual fields are being tested with gross confrontation. A right sided visual field deficit for both eyes is shown. This is a right hemianopia from a lesion behind the optic chiasm involving the left optic tract, radiation or striate cortex. Cranial Nerve II- Fundoscopy The first photograph is of a fundus showing papilledema. The findings of papilledema include 1. Loss of venous pulsation 2. Swelling of the optic nerve head so there is loss of the disc margin 3. Venous engorgement 4. Disc hyperemi 5. Loss of the physiologic cup an 6. Flame shaped hemorrhages. This photograph shows all the signs except the hemorrhages and loss of venous pulsations. The second photograph shows optic atrophy, which is pallor of the optic disc resulting form damage to the optic nerve from pressure, ischemia, or demyelination. Images Courtesy Dr. Kathleen Digre, University of Uta Cranial Nerves 2 & 3- Pupillary Light Refle The swinging flashlight test is used to show a relative afferent pupillary defect or a Marcus Gunn pupil of the left eye. The left eye has perceived less light stimulus (a defect in the sensory or afferent pathway) then the opposite eye so the pupil dilates with the same light stimulus that caused constriction when the normal eye was stimulated. Video Courtesy of Dr.Daniel Jacobson, Marshfield Clini and Dr. Kathleen Digre, University of Uta Cranial Nerves 3, 4 & 6- Inspection & Ocular Alignmen This patient with ocular myasthenia gravis has bilateral ptosis, left greater than right. There is also ocular misalignment because of weakness of the eye muscles especially of the left eye. Note the reflection of the light source doesn't fall on the same location of each eyeball. Video Courtesy of Dr.Daniel Jacobson, Marshfield Clini and Dr. Kathleen Digre, University of Uta Cranial Nerves 3, 4 & 6- Versions • The first patient shown has incomplete abduction of her left eye from a 6th nerve palsy. • The second patient has a left 3rd nerve palsy resulting in ptosis, dilated pupil, limited adduction, elevation, and depression of the left eye. Second Video Courtesy of Dr.Daniel Jacobson, Marshfield Clini and Dr. Kathleen Digre, University of Uta Cranial Nerves 3, 4 & 6- Duction Each eye is examined with the other covered (this is called ductions). The patient is unable to adduct either the left or the right eye. If you watch closely you can see nystagmus upon abduction of each eye. When both eyes are tested together (testing versions) you can see the bilateral adduction defect with nystagmus of the abducting eye. This is bilateral internuclear ophthalmoplegia often caused by a demyelinating lesion effecting the MLF bilaterally. The adduction defect occurs because there is disruption of the MLF (internuclear) connections between the abducens nucleus and the lower motor neurons in the oculomotor nucleus that innervate the medial rectus muscle. Saccades Smooth Pursui The patient shown has progressive supranuclear palsy. As part of this disease there is disruption of fixation by square wave jerks and impairment of smooth pursuit movements. Saccadic eye movements are also impaired. Although not shown in this video, vertical saccadic eye movements are usually the initial deficit in this disorder. Video Courtesy of Dr.Daniel Jacobson, Marshfield Clini and Dr. Kathleen Digre, University of Utah Optokinetic Nystagmu This patient has poor optokinetic nystagmus when the tape is moved to the right or left. The patient lacks the input from the parietal-occipital gaze centers to initiate smooth pursuit movements therefore her visual tracking of the objects on the tape is inconsistent and erratic. Patients who have a lesion of the parietal-occipital gaze center will have absent optokinetic nystagmus when the tape is moved toward the side of the lesion. Vestibulo-ocular refle The vestibulo-ocular reflex should be present in a comatose patient with intact brainstem function. This is called intact "Doll’s eyes" because in the old fashion dolls the eyes were weighted with lead so when the head was turned one way the eyes turned in the opposite direction. Absent "Doll’s eyes" or vestibulo-ocular reflex indicates brainstem dysfunction at the midbrain-pontine level. Vergenc Light-near dissociation occurs when the pupils don't react to light but constrict with convergence as part of the near reflex. This is what happens in the Argyll-Robertson pupil (usually seen with neurosyphilis) where there is a pretectal lesion affecting the retinomesencephalic afferents controlling the light reflex but sparing the occipitomesencephalic pathways for the near reflex. Video Courtesy of Dr.Daniel Jacobson, Marshfield Clini and Dr. Kathleen Digre, University of Uta Cranial Nerve 5- Sensor There is a sensory deficit for both light touch and pain on the left side of the face for all divisions of the 5th nerve. Note that the deficit is first recognized just to the left of the midline and not exactly at the midline. Patients with psychogenic sensory loss often identify the sensory change as beginning right at the midline. Cranial Nerves 5 & 7 - Corneal refle A patient with an absent corneal reflex either has a CN 5 sensory deficit or a CN 7 motor deficit. The corneal reflex is particularly helpful in assessing brainstem function in the unconscious patient. An absent corneal reflex in this setting would indicate brainstem dysfunction. Cranial Nerve 5- Motor • The first patient shown has weakness of the pterygoids and the jaw deviates towards the side of the weakness. • The second patient shown has a positive jaw jerk which indicates an upper motor lesion affecting the 5th cranial nerve. First Video Courtesy of Alejandro Stern, Stern Foundation Cranial Nerve 7- Motor • The first patient has weakness of all the muscles of facial expression on the right side of the face indicating a lesion of the facial nucleus or the peripheral 7th nerve. • The second patient has weakness of the lower half of his left face including the orbicularis oculi muscle but sparing the forehead. This is consistent with a central 7th or upper motor neuron lesion. Video Courtesy of Alejandro Stern, Stern Foundatio Cranial Nerve 7- Sensory, Tast The patient has difficulty correctly identifying taste on the right side of the tongue indicating a lesion of the sensory limb of the 7th nerve. Cranial Nerve 8- Auditory Acuity, Weber & Rinne Test This patient has decreased hearing acuity of the right ear. The Weber test lateralizes to the right ear and bone conduction is greater than air conduction on the right. He has a conductive hearing loss. Cranial Nerve 8- Vestibula Patients with vestibular disease typically complain of vertigo – the illusion of a spinning movement. Nystagmus is the principle finding in vestibular disease. It is horizontal and torsional with the slow phase of the nystagmus toward the abnormal side in peripheral vestibular nerve disease. Visual fixation can suppress the nystagmus. In central causes of vertigo (located in the brainstem) the nystagmus can be horizontal, upbeat, downbeat, or torsional and is not suppressed by visual fixation. Cranial Nerve 9 & 10- Moto When the patient says "ah" there is excessive nasal air escape. The palate elevates more on the left side and the uvula deviates toward the left side because the right side is weak. This patient has a deficit of the right 9th & 10th cranial nerves. Video Courtesy of Alejandro Stern, Stern Foundatio Cranial Nerve 9 & 10- Sensory and Motor: Gag Refle Using a tongue blade, the left side of the patient's palate is touched which results in a gag reflex with the left side of the palate elevating more then the right and the uvula deviating to the left consistent with a right CN 9 & 10 deficit. Video Courtesy of Alejandro Stern, Stern Foundation Cranial Nerve 11- Moto When the patient contracts the muscles of the neck the left sternocleidomastoid muscle is easily seen but the right is absent. Looking at the back of the patient, the left trapezius muscle is outlined and present but the right is atrophic and hard to identify. These findings indicate a lesion of the right 11th cranial nerve. Video Courtesy of Alejandro Stern, Stern Foundation Cranial Nerve 12- Moto Notice the atrophy and fasciculation of the right side of this patient's tongue. The tongue deviates to the right as well because of weakness of the right intrinsic tongue muscles. These findings are present because of a lesion of the right 12th cranial nerve.
over 9 years ago
Explains how the resting membrane potential is maintained. And how the ion concentration is, as it is at rest. http://www.facebook.com/ArmandoHasudungan PDF: https://docs.google.com/open?id=0B8Ss3-wJfHrpcG9SaDRwSHdpVUk
over 6 years ago
So you're sitting in a bus when you see a baby smile sunnily and gurgle at his mother. Your automatic response? You smile too. You're jogging in the park, when you see a guy trip over his shoelaces and fall while running. Your knee jerk reaction? You wince. Even though you're completely fine and unscathed yourself. Or, to give a more dramatic example; you're watching Titanic for the umpteenth time and as you witness Jack and Rose's final moments together, you automatically reach for a tissue and wipe your tears in whole hearted sympathy ( and maybe blow your nose loudly, if you're an unattractive crier like yours truly). And here the question arises- why? Why do we experience the above mentioned responses to situations that have nothing to do with us directly? As mere passive observers, what makes us respond at gut level to someone else's happiness or pain, delight or excitement, disgust or fear? In other words, where is this instinctive response to other people's feelings and actions that we call empathy coming from? Science believes it may have discovered the answer- mirror neurons. In the early 1990s, a group of scientists (I won't bore you with the details of who, when and where) were performing experiments on a bunch of macaque monkeys, using electrodes attached to their brains. Quite by accident, it was discovered that when the monkey saw a scientist holding up a peanut, it fired off the same motor neurons in its brain that would fire when the monkey held up a peanut itself. And that wasn't all. Interestingly, they also found that these motor neurons were very specific in their actions. A mirror neuron that fired when the monkey grasped a peanut would also fire only when the experimenter grasped a peanut, while a neuron that fired when the monkey put a peanut in its mouth would also fire only when the experimenter put a peanut in his own mouth. These motor neurons came to be dubbed as 'mirror neurons'. It was a small leap from monkeys to humans. And with the discovery of a similar, if not identical mirror neuron system in humans, the studies, hypotheses and theories continue to build. The strange thing is that mirror neurons seem specially designed to respond to actions with clear goals- whether these actions reach us through sight, sound, smell etc, it doesn't matter. A quick example- the same mirror neurons will fire when we hop on one leg, see someone hopping, hear someone hopping or hear or read the word 'hop'. But they will NOT respond to meaningless gestures, random or pointless sounds etc. Instead they may well be understanding the intentions behind the related action. This has led to a very important hypothesis- the 'action understanding' ability of mirror neurons. Before the discovery of mirror neurons, scientists believed our ability to understand each other, to interpret and respond to another's feeling or actions was the result of a logical thought process and deduction. However, if this 'action understanding' hypothesis is proved right, then it would mean that we respond to each other by feeling, instead of thinking. For instance, if someone smiles at you, it automatically fires up your mirror neurons for smiling. They 'understand the action' and induce the same sensation within you that is associated with smiling. You don't have to think about what the other person intends by this gesture. Your smile flows thoughtlessly and effortlessly in return. Which brings us to yet another important curve- if mirror neurons are helping us to decode facial expressions and actions, then it stands to reason that those gifted people who are better at such complex social interpretations must be having a more active mirror neuron system.(Imagine your mom's strained smile coupled with the glint in her eye after you've just thrown a temper tantrum in front of a roomful of people...it promises dire retribution my friends. Trust me.) Then does this mean that people suffering from disorders such as autism (where social interactions are difficult) have a dysfunctional or less than perfect mirror neuron system in some way? Some scientists believe it to be so. They call it the 'broken mirror hypothesis', where they claim that malfunctioning mirror neurons may be responsible for an autistic individual's inability to understand the intention behind other people's gestures or expressions. Such people may be able to correctly identify an emotion on someone's face, but they wouldn't understand it's significance. From observing other people, they don't know what it feels like to be sad, angry, surprised or scared. However, the jury is still out on this one folks. The broken mirror hypothesis has been questioned by others who are still skeptical about the very existence of these wonder neurons, or just how it is that these neurons alone suffered such a developmental hit when the rest of the autistic brain is working just dandy? Other scientists argue that while mirror neurons may help your brain to understand a concept, they may not necessarily ENCODE that concept. For instance, babies understand the meaning behind many actions without having the motor ability to perform them. If this is true, then an autistic person's mirror neurons are perfectly fine...they were just never responsible for his lack of empathy in the first place. Slightly confused? Curious to find out more about these wunderkinds of the human brain? Join the club. Whether you're an passionate believer in these little fellas with their seemingly magical properties or still skeptical, let me add to your growing interest with one parting shot- since imitation appears to be the primary function of mirror neurons, they might well be partly responsible for our cultural evolution! How, you ask? Well, since culture is passed down from one generation to another through sharing, observation followed by imitation, these neurons are at the forefront of our lifelong learning from those around us. Research has found that mirror neurons kick in at birth, with infants just a few minutes old sticking their tongues out at adults doing the same thing. So do these mirror neurons embody our humanity? Are they responsible for our ability to put ourselves in another person's shoes, to empathize and communicate our fellow human beings? That has yet to be determined. But after decades of research, one thing is for sure-these strange cells haven't yet ceased to amaze and we definitely haven't seen the last of them. To quote Alice in Wonderland, the tale keeps getting "curiouser and curiouser"!
about 6 years ago
The human brain is the main organ of the human central nervous system. It is located in the head, protected by the skull. It has the same general structure as the brains of other mammals, but with a more developed cerebral cortex. Large animals such as whales and elephants have larger brains in absolute terms, but when measured using a measure of relative brain size, which compensates for body size, the quotient for the human brain is almost twice as large as that of a bottlenose dolphin, and three times as large as that of a chimpanzee, though the quotient for a treeshrew's brain is larger than that of a human's. Much of the size of the human brain comes from the cerebral cortex, especially the frontal lobes, which are associated with executive functions such as self-control, planning, reasoning, and abstract thought. The area of the cerebral cortex devoted to vision, the visual cortex, is also greatly enlarged in humans compared to other animals.
over 4 years ago
The nervous system is composed of more than 100 billion cells known as neurons . A neuron is a cell in the nervous system whose function it is to receive and transmit information . As you can see in Figure3.2, Components of the Neuron , neurons are made up of three major parts: a cell body, or soma , which contains the nucleus of the cell and keeps the cell alive ; a branching treelike fiber known as the dendrite , which collects information from other cells and sends the information to the soma ; and a long, segmented fiber known as the axon , which transmits information away from the cell body toward other neurons or to the muscles and glands .
over 4 years ago
Anatomy and Physiology, help, spinal cord, neural tissue, pia mater, dermatomes, dura mater, arachnoid mater, spinal anatomy, cauda equina, filum terminale, ganglia, dorsal root, ventral root, nervous system.
over 6 years ago