neuro999cebu
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Normal Anatomy of the Brain
Maximum one post per topic:
Topic 1:
Name the lobes of the brain and the purported "function" of each.
Topic 2:
Name the parts of the brainstem and the functions it supports.
Topic 3:
Name the ventricles and the pathway for cerebrospinal fluid circulation
Topic 4:
Name the cranial nerves (from I to VI) and the functions of each.
Topic 5:
Name the cranial nerves (from VII to XII) and the functions of each.
Topic 6:
Name the parts of the major arteries of the Circle of Willis; what parts of the brain do these arteries supply?
Topic 7:
Name the major parts of the Venous System in the brain.
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1/20/2019, 9:40 pm
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evaceballos
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Re: Normal Anatomy-Brain- Topic 4: cranial nerves 1-6 and functions of each
CRANIAL NERVE 1- OLFACTORY NERVE
It is responsible for transmitting sensory signals to the brain with regards to the sense of smell. Anosmia (inability to detect scents) can be experienced when there is disruption of this nerve.
CRANIAL NERVE 2- OPTIC NERVE
It is responsible for vision and it carries visual information from the retina of the eye to the brain. It has special receptors called rods (night vision) and cones (daylight vision). Optic neuritis is a disorder that can lead to visual disturbance or even blindness.
CRANIAL NERVE 3- OCULOMOTOR NERVE
It innervates the levator palpebrae superioris (eye opening); ptosis can be experienced when the nerve is disrupted
It has 2 main functions:
a. It provides motor function of the 4 out of 6 extra ocular muscles of the eye (SR, MR, IR, IO) that helps move the eyes and focus on objects. Disorder: External strabismus
b. It carries parasympathetic fibers to the iris causing it to constrict in a bright light.
CRANIAL NERVE 4- TROCHLEAR NERVE
It controls one of the extra ocular muscles of the eye which is known as superior oblique (SO) and is responsible for downward and inward movement of the eye. A lesion can cause vertical diplopia that improves when tilting the head away from the affected eye.
CRANIAL NERVE 5- TRIGEMINAL NERVE
It has both sensory and motor functions in the face and mouth. It is divided into 3 divisions:
a. Ophthalmic- sends sensory information from the upper part of the face (forehead, scalp, upper eyelid); responsible for corneal blink reflex
b. Maxillary- sends sensory information from the middle part of the face (cheeks, upper lip, nasal cavity)
c. Mandibular- sends sensory information from the ears, lower lip and chin and it also has motor function which involves facial muscles for chewing
Complication: Trigeminal neuralgia (facial pain)
CRANIAL NERVE 6- ABDUCENS NERVE
It innervates one the extra ocular muscles of the eye which is known as lateral rectus (LR) and is responsible for lateral movement or gaze
Lesion can cause double vision or internal strabismus (horizontal diplopia)
References:
Pressman, P. (2018). The cranial nerves and their functions. Retrieved from: https://www.verywellhealth.com/the-cranial-nerves-2488654
Seladi-Schulman, J. (2018). The 12 cranial nerves. Retrieved from: https://www.healthline.com/health/12-cranial-nerves
Image: https://courses.lumenlearning.com/boundless-ap/chapter/cranial-nerves/
Last edited by evaceballos, 1/26/2019, 1:40 pm
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1/24/2019, 7:10 am
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jayanncalderon
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Re: Normal Anatomy of the Brain_Topic 1
FRONTAL LOBE
Both right and left are involved in voluntary eye movements, somatic motor control, planning and sequencing of movements, and emotional affect. The left frontal lobe is essential for motor control of speech (Broca’s area). It is located at the front of the brain and is associated with reasoning, motor skills, higher level cognition, and expressive language. At the back of the frontal lobe, near the central sulcus, lies the motor cortex. This area of the brain receives information from various lobes of the brain and utilizes this information to carry out body movements. Damage to the frontal lobe can lead to changes in sexual habits, socialization, and attention as well as increased risk-taking.
TEMPORAL LOBE
Both right and left handle auditory and visual perception, learning and memory, emotional affect, and olfaction. The dominant temporal lobe influences comprehension of speech (Wernicke’s area). The nondominant temporal lobe mediates prosody and spatial relationships.
It is located on the bottom section of the brain. This lobe is also the location of the primary auditory cortex, which is important for interpreting sounds and the language we hear. The hippocampusis also located in the temporal lobe, which is why this portion of the brain is also heavily associated with the formation of memories. Damage to the temporal lobe can lead to problems with memory, speech perception, and language skills.
PARIETAL LOBE
Handle cortical sensation, motor control, and visual perception. The dominant parietal lobe also handles ideomotor praxis. The nondominant parietal lobe controls spatial orientation. It is located in the middle section of the brain and is associated with processing tactile sensory information such as pressure, touch, and pain. A portion of the brain known as the somatosensory cortex is located in this lobe and is essential to the processing of the body's senses.
OCCIPITAL LOBE
Mainly handle visual perception and involuntary smooth pursuit eye movements. It is located at the back portion of the brain and is associated with interpreting visual stimuli and information. The primary visual cortex, which receives and interprets information from the retinas of the eyes, is located in the occipital lobe. Damage to this lobe can cause visual problems such as difficulty recognizing objects, an inability to identify colors, and trouble recognizing words.
Berkowitz, A. (2016) Clinical Neurology and Neuroanatomy A Localization-Based Approach chapter 7 p53
Cherry, K. (2018 November) A Guide to the Anatomy of the Brain. Retrieved from https://www.verywellmind.com/the-anatomy-of-the-brain-2794895
Rolak, L. (2010) Neurology secrets 5th ed. Chapter 2. Pg 51
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1/24/2019, 3:32 pm
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piabautista
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Re: Normal Anatomy of the Brain Topic 6:
The brain is supplied by the two internal carotid and the two vertebral arteries.
The Circle of Willis begins to form when the right and left internal carotid artery (ICA) enters the cranial cavity and each one divides into two main branches: the anterior cerebral artery (ACA) and middle cerebral artery (MCA).
ANTERIOR CEREBRAL ARTERY (ACA)
This is the smaller terminal branch of the internal carotid artery. It supplies mostly the midline portion of the frontal lobe and superior medial parietal lobe. It is joined to the anterior cerebral artery of the opposite side by the anterior communicating artery.
MIDDLE CEREBRAL ARTERY (MCA)
Though it is not part of the circle of Willis, it is the largest branch of the internal carotid artery. It supplies most of the lateral surface of the hemisphere, except the superior position of the parietal lobe (via ACA) and the inferior portion of the temporal lobe and occipital lobe.
The Anterior Cerebral Artery, Anterior Communicating Artery, and Middle Cerebral Artery form the anterior half, known as the anterior cerebral circulation.
POSTERIOR CEREBRAL ARTERY (PCA)
The PCAs mostly supply blood to the occipital lobe and inferior portion of the temporal lobe. Posteriorly, the basilar artery that is formed by the left and right vertebral arteries, branches into a left and right posterior cerebral artery, forming the posterior circulation.
The posterior cerebral artery completes the circle of Willis by joining the anterior circulation formed by the internal carotid artery via the posterior communicating arteries.
VERTEBRAL ARTERY
It supplies the posterior fossa and occipital lobes, as well as provides segmental vertebral and spinal column blood supply. At the lower border of the pons, it joins the vessel of the opposite side to form the basilar artery.
Gupta, G. (2017). Circle of Willis Anatomy. Retrived from https://emedicine.medscape.com/article/1877617-overview.
Ahmad, M. (2018). Circle of Willis, Cerebral Circulation, Anatomy, Location & clinical significance of circle of Willis. Retrived from https://www.medicosite.com/circle-of-willis/
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1/26/2019, 8:13 am
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paul ople
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Re: Normal Anatomy of the Brain
Topic 7
The major venous system of the brain
First we all know that veins of the central nervous system drain deoxygenated blood from the cerebrum, cerebellum, brainstem and spinal cord. After emptying into the dural venous sinuses, cerebral venous blood flows into the internal jugular veins before it is returned to the heart.
The veins draining the brain parenchyma may be divided into superficial and deep veins. The superficial veins primarily drain the cerebral cortex, whereas the deep veins drain the deep structures within the hemispheres.
Superficial veins
The superficial venous system comprises:
Sagittal sinuses
Cortical veins
The cortical venous system is further divided into superior, middle and inferior groups.
There are several important superficial cerebral veins:
Superior anastamotic vein of Trolard
Superficial middle cerebral vein (Sylvian vein)
Inferior anastomotic vein of Labbé
Inferior anastomotic vein of Labbé
The vein of Labbé connects the superficial middle cerebral artery with the transverse sinus.
Superior anastomotic vein of Trolard
The superior anastomotic vein of Trolard connects the superior sagittal sinus with the superficial middle cerebral vein. It is usually the smallest of the three superficial veins.
Superficial middle cerebral vein
The superficial middle cerebral vein is also known as the Sylvian vein, and it usually courses along the Sylvian fissure (lateral sulcus) picking up veins from the surrounding operculum (brain region surrounding the lateral sulcus) as it runs postero-anteriorly. The superficial middle cerebral vein then drains into the cavernous sinus after curving around the anterior temporal lobe.
Lastly, the deep veins.
Deep veins
The deep cerebral venous drainage system comprises:
Sinuses:
Transverse
Straight
Sigmoid
Deep cerebral veins:
Subependymal
Medullary
This system drains the thalamus, hypothalamus, internal capsule, septum pellucidum, choroid plexuses, corpus striatum, and the white matter.
References:
Varshney S, Malhotra M, Gupta P, Gairola P, Kaur N. Cavernous sinus thrombosis of nasal origin in children. Indian J Otolaryngol Head Neck Surg 2015;67:100-5.
https://www.msdmanuals.com/en-gb/professional/eye-disorders/orbital-diseases/cavernous-sinus-thrombosis [accessed on 14/10/2018]
DiNubile MJ Septic thrombosis of the cavernous sinuses. Arch Neurol.1988;45567- 572
Coutinho JM, Middeldorn S, Stam J; Advances in the treatment of cerebral venous thrombosis. Curr Treat Options Neurol. 2014 Jul16(7):299. Doi: 10.1007/s11940-014-0299-0.
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1/26/2019, 12:19 pm
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Grace Napisa
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Re: Name the parts of the brainstem and the functions it supports.
Topic 2
The brainstem is the region of the brain that connects the cerebrum with the spinal cord. It consists of the midbrain, medulla oblongata, and the pons. Motor and sensory neurons travel through the brainstem allowing for the relay of signals between the brain and the spinal cord. Most cranial nerves are found in the brainstem.
Here are the parts of the Brainstem:
First is the Midbrain:
This involved in processes such as vision, hearing, eye movement, and body movement. Major structures of the midbrain include the tectum and cerebral peduncle. The tectum is composed of rounded bulges of brain matter that are involved in visual and auditory reflexes. The cerebral peduncle consists of large bundles of nerve fiber tracts that connect the forebrain to the hindbrain.
Cross-section of the midbrain at the level of the superior colliculus.
Second is Medulla:
This is involved in maintaining vital body functions, such as breathing and heart rate. So you’ll notice these are the autonomic processes. In other words, these are the processes that are going to happen whether you think about it or not. These are regulated by the medulla. This also helps to regulate autonomic functions, such as breathing and blood pressure.Thgis also responsible for many reflexes of the body or thing that usually do not voluntarily control such as sneezing, vomiting and coughing.
Cross-section of the rostral (superior) medulla.
Lastly, The Pons:
Involved in motor control and sensory analysis.
Also assists in the regulation of breathing, as well as states of sleep and arousal. The pons has two over-arching roles. The first is the regulation of breathing. There is a structure called the pneumotaxic center. This is really just a big word for a center of nerve cells that control the amount of air you breathe and how many times a minute you take a breath, which is known as the breathing rate. Lets say, when you run, you begin to breathe faster, and when you lie down on the couch to rest, you breathe more slowly. Moreover, the pons is involved in the transmission of signals to and from other structures in the brain, such as the cerebrum or the cerebellum. The pons is also involved in sensations such as hearing, taste, and balance.
Cross-section of the middle pons (at the level of cranial nerve V).
REFERENCES:
Pietrangelo, A. (2016, August 31). Brain Stem Stroke. Retrieved August 24, 2017, from http://www.healthline.com/health/brain-stem-stroke
Jones, J. (n.d.). Brainstem | Radiology Reference Article. Retrieved August 24, 2017, from https://radiopaedia.org/articles/brainstem
https://en.wikipedia.org/wiki/Brainstem
http://www.interactive-biology.com/1835/the-3-parts-of-the-brain-stem-and-their-functions-episode-27/
https://study.com/academy/lesson/parts-of-the-brain-stem-the-medulla-oblongata-and-pons.html
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1/27/2019, 11:35 am
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neuro999cebu
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Re: Normal Anatomy of the Brain
For this part, it's OK to lift verbatim from your sources. However, perfect scores are for those who include pictures in their posts.
quote: neuro999cebu wrote:
Maximum one post per topic:
Topic 1:
Name the lobes of the brain and the purported "function" of each.
Topic 2:
Name the parts of the brainstem and the functions it supports.
Topic 3:
Name the ventricles and the pathway for cerebrospinal fluid circulation
Topic 4:
Name the cranial nerves (from I to VI) and the functions of each.
Topic 5:
Name the cranial nerves (from VII to XII) and the functions of each.
Topic 6:
Name the parts of the major arteries of the Circle of Willis; what parts of the brain do these arteries supply?
Topic 7:
Name the major parts of the Venous System in the brain.
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1/29/2019, 1:27 am
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ocampodannika
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Re: Normal Anatomy of the Brain- TOPIC 5
Topic 5:
Name the cranial nerves (from VII to XII) and the functions of each.
Overview of Cranial Nerves
Figure 1.
CN VII: Facial Nerve (Fig. 2)
Function: The facial nerve is the nerve of the second pharyngeal arch and provides motor innervation to all the muscles of facial expression, and sensory innervation to the anterior 2/3 of the tongue. It does not supply the skin but its branches communicate with the branches of trigeminal nerve (CN V).
Figure 2
CN VIII: Vestibulocochlear Nerve (Fig. 3)
Function: A sensory nerve that consists of two sets of fibers: vestibular (concerned with position sense and head movement) and cochlear (concerned with hearing).
Figure 3.
CN IX: Glossopharyngeal Nerve (Fig. 4)
Function: Is both a motor and sensory nerve which assists swallowing and promotes salivation, and conducts sensation from the pharynx and the back of the tongue and carries impulses, which influence arterial blood pressure and respiration from the carotid sinus and carotid body.
Figure 4
CN X: Vagus Nerve (Fig. 5)
Function: Also composed of motor and sensory nerve vibers. Innervates the heart and great vessels within the thorax (the larynx, trachea, bronchi, and lungs), and much of the alimentary tract of the pharynx to the splenic flexure of the colon. It also supplies glands associated with the alimentary tract (liver & pancreas).
Figure 5
CN XI: Accessory Nerve (Fig. 6)
Function: Brings about movements of the soft palate, pharynx, and larynx, and controls the movements of the sternocleidomastoid and trapezius muscles.
Figure 6
CN XII: Hypoglossal Nerve (Fig. 7)
Function: Provides motor innervation to the muscles of the tongue (palatoglossus, genioglossus, hyoglossus, styloglossus).
Figure 7
Source:
Snell, R. S. (2012). Clinical neuroanatomy (9th ed.). Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins.
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1/29/2019, 4:04 pm
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evaceballos
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Re: Normal Anatomy of the Brain- Topic 3
Name the ventricles and the pathway for cerebrospinal fluid circulation
CSF is formed within the ventricles by small, delicate tufts of specialized tissue called the choroid plexus. Beginning in the lateral ventricles, CSF flows through two passageways into the third ventricle through the interventricular foramen (also called the foramen of Monro). From the third ventricle it flows down a long, narrow passageway (the aqueduct of Sylvius) into the fourth ventricle. From the fourth ventricle it passes through three small openings (foramina) into the subarachnoid space surrounding the brain and spinal cord. CSF then flows into the subarachnoid space through the foramina of Luschka (there are two of these) and the foramen of Magendie (only one of these). CSF is absorbed through blood vessels over the surface of the brain back into the bloodstream. Some absorption also occurs through the lymphatic system. Once in the bloodstream, it is carried away and filtered by our kidneys and liver in the same way as are our other body fluids. (Roumila, n.d.)
The ventricular system is the major pathway for the flow of CSF. CSF also flows directly from the ventricles into the brain tissue surrounding them. This is shown by the broken arrows. Here the CSF passes through the spaces between the cells to where it eventually enters the subarachnoid space. It is believed that the brain tissue does not absorb any CSF, but simply provides another pathway for the fluid moving to the subarachnoid space. Some small amounts of CSF are also absorbed into lymphatic channels along the membranes covering the nerves (nerve sheaths) as they leave the brain stem and spinal cord . (Roumila, n.d.)
There are 4 ventricles: 2 lateral ventricles, 3rd ventricle and 4th ventricle
Illustration by Lynne Larson
Reference:
Roumila, K. (n.d.). Brain 101. The Ventricles and CSF flow. Hydrocephalus association. Retrieved from: https://www.hydroassoc.org/brain-101-the-ventricles-and-csf-flow/
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2/6/2019, 12:14 am
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