1.Anatomy of the Medulla
2. Introduction to Brainstem Anatomy of the brainstem includes ( midbrain-pons-medulla ) is very complicated !! •It connects spinal cord to the cerebrum. • The mid brain pons, and medulla are connected to cerebellum posteriorly. •1 - ascending an descending tracts that connect brain to spinal cord. •2 - cranial nerves nuclei and their connections •3 - Reticular formation •4 - others e.g (olivarynucleus in MO tapizusbody in pons and red nucleus in MB )
3. Medulla oblongata •The medulla oblongata is the part of the brainstem between the pons and spinal cord •It extends through the foramen magnum to the level of the atlas. •Medulla is vital for our function, without medulla we die. •Above the foramen magnum it is embraced dorsally by the cerebellar hemispheres. 1.The lower end which contains the upward continuation of the central canal of the spinal cord is the ‘closed part of the medulla’, 2.The upper end, where the canal comes to the surface as the lower part of the floor of the fourth ventricle, is the ‘open part’.
4. Medulla contd….. MO is lowest 3 cm of the brainstem •it extend from the ponto- medullary junction until plane below foramina magnum for about 0.5 cm. •Medulla spinalis have a central canal which prolonged into its lower half to open in the fourth ventricle at its upper half. •CSF is encircle the MO from outside ( subarachnoid space ) and inside ( central canal ). •MO is between the two lobes of cerebellum ( anterior cerebellar notch )
5. EXTERNAL FEATURES AND RELATIONS • 3Cm long. • Located at the caudal portion of brainstem • Upper limit is cerebello-pontine angle • Transverse plane that above C1 (suboccipital) intersects upper border of atlas dorsally and centre of dens ventrally marks lower limit
6. VENTRAL SURFACE • Ventral median fissure extends from foramen coecum to caudal end of pyramid decussation • Lateral to median fissure is pyramid • Lat to pyramid is the ventrolateral sulcus (VLS) • Hypoglossal nerve rootlets emerge from VLS • Lat to VLS is olive which contains inf olivary nucleus • Inferior cerebellar peduncle connects medulla with cerebellum and forms side wall of caudal half of fourth ventricle
7. Ventral Surface Pyramid: Swelling on each side of anterior median fissure. • Composed of bundles of nerve fibers, (corticospinal fibers) originate from the precentral gyrus of the cerebral cortex. • The pyramids taper inferiorly and majority of the descending fibers decussate to the opposite side. Olive: • Olives are the anterolateral oval elevations produced by the underlying inferior olivary nuclei. • From the groove between the pyramid and the olive, the rootlets of the hypoglossal nerve emerge
8. LATERAL ASPECT • Roots of glossopharyngeal , vagus and cranial division of accessory nerves are attached to the medulla dorsal to olive.
9. Dorsal surface At dorsal surface of closed part of medulla, gracile and cuneate fasciculi continue from the spinal
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
1.Anatomy of the Medulla
2. Introduction to Brainstem Anatomy of the brainstem includes ( midbrain-pons-medulla ) is very complicated !! •It connects spinal cord to the cerebrum. • The mid brain pons, and medulla are connected to cerebellum posteriorly. •1 - ascending an descending tracts that connect brain to spinal cord. •2 - cranial nerves nuclei and their connections •3 - Reticular formation •4 - others e.g (olivarynucleus in MO tapizusbody in pons and red nucleus in MB )
3. Medulla oblongata •The medulla oblongata is the part of the brainstem between the pons and spinal cord •It extends through the foramen magnum to the level of the atlas. •Medulla is vital for our function, without medulla we die. •Above the foramen magnum it is embraced dorsally by the cerebellar hemispheres. 1.The lower end which contains the upward continuation of the central canal of the spinal cord is the ‘closed part of the medulla’, 2.The upper end, where the canal comes to the surface as the lower part of the floor of the fourth ventricle, is the ‘open part’.
4. Medulla contd….. MO is lowest 3 cm of the brainstem •it extend from the ponto- medullary junction until plane below foramina magnum for about 0.5 cm. •Medulla spinalis have a central canal which prolonged into its lower half to open in the fourth ventricle at its upper half. •CSF is encircle the MO from outside ( subarachnoid space ) and inside ( central canal ). •MO is between the two lobes of cerebellum ( anterior cerebellar notch )
5. EXTERNAL FEATURES AND RELATIONS • 3Cm long. • Located at the caudal portion of brainstem • Upper limit is cerebello-pontine angle • Transverse plane that above C1 (suboccipital) intersects upper border of atlas dorsally and centre of dens ventrally marks lower limit
6. VENTRAL SURFACE • Ventral median fissure extends from foramen coecum to caudal end of pyramid decussation • Lateral to median fissure is pyramid • Lat to pyramid is the ventrolateral sulcus (VLS) • Hypoglossal nerve rootlets emerge from VLS • Lat to VLS is olive which contains inf olivary nucleus • Inferior cerebellar peduncle connects medulla with cerebellum and forms side wall of caudal half of fourth ventricle
7. Ventral Surface Pyramid: Swelling on each side of anterior median fissure. • Composed of bundles of nerve fibers, (corticospinal fibers) originate from the precentral gyrus of the cerebral cortex. • The pyramids taper inferiorly and majority of the descending fibers decussate to the opposite side. Olive: • Olives are the anterolateral oval elevations produced by the underlying inferior olivary nuclei. • From the groove between the pyramid and the olive, the rootlets of the hypoglossal nerve emerge
8. LATERAL ASPECT • Roots of glossopharyngeal , vagus and cranial division of accessory nerves are attached to the medulla dorsal to olive.
9. Dorsal surface At dorsal surface of closed part of medulla, gracile and cuneate fasciculi continue from the spinal
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
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2. OBJECTIVES
1. Describe external features of the brain stem
2. Identification of the tracts and nuclei in the brain stem.
3. Orientation of the cranial nerve nuclei in the brain stem.
4. Highlight the connections and significance of the reticular
formation.
3. INTRODUCTION
• The brainstem is made up of the medulla oblongata, the pons, and
the midbrain and occupies the posterior cranial fossa of the skull.
• It is stalk-like in shape and connects the narrow spinal cord with the
expanded forebrain.
• The brainstem has 4 broad functions:
It serves as a conduit for the ascending tracts and descending tracts
connecting the spinal cord to the different parts of the higher centers in
the forebrain.
It contains important reflex centers associated with the control of
vomiting, respiration and the cardiovascular system and with the
control of consciousness
It contains the important nuclei of cranial nerves III through XII.
It contains the reticular formation.
6. GROSS FEATURES
• The medulla oblongata is conical (bulb) in shape broad superiorly and
narrow inferiorly.
• It connects the pons with the spinal cord.
• On each side of its anteromedian fissure there is a swelling named
the pyramid.
• The pyramid tapers inferiorly where majority of corticospinal fibers
cross to the opposite side.
• Posterolateral to the pyramids are the olives which are oval elevations
produced by the inferior olivary nuclei.
7. • Rootlets of the hypoglossal nerve emerge between the pyramid and
olive on each side.
• Posterior to the olives are the inferior cerebellar peduncles.
• Rootlets of the glossopharyngeal, vagus and accessory nerves
emerge in the groove between the olives and inferior cerebellar
peduncles.
8. • The posterior surface of the rostral medulla forms the floor of the 4th
ventricle.
• The posterior surface of the caudal medulla possesses a posterior
median sulcus on each side of which there is an elongated swelling,
the gracile tubercle produced by gracile nucleus.
• Lateral to the gracile tubercle is a cuneate tubercle produced by
cuneate nucleus.
10. INTERNAL STRUCTURES OF THE
MEDULLA
• Internal features of medulla are illustrated in transverse sections
through 3 levels:
Caudal level, level of motor decussation.
Middle level, level of sensory decussation.
Superior level, level of open medulla.
11. Caudal medulla (Level of motor
decussation)
• At transition from the spinal cord to the medulla, the pattern of gray
and white matter undergoes considerable rearrangement.
• The ventral horn becomes much attenuated.
• The dorsal horn is replaced by the spinal trigeminal nucleus.
• Superficial to this nucleus is the spinal tract of the trigeminal nerve
descending to the spinal trigeminal nucleus.
• In the ventral aspect majority of pyramidal tract fibers decussate
(motor decussation) and pass laterally, dorsally and caudally to form
the lateral corticospinal tract.
12.
13. Middle medulla (Level of sensory
decussation)
• Gracile and cuneate nuclei appear beneath their respective tracts.
• Axons of gracile and cuneate nuclei course medially and ventrally as
internal arcuate fibers which decussate at this level forming sensory
decussation.
• The decussated fibers turn rostrally forming medial lemniscus (on
each side) which ascends in the brain stem to end in the thalamus.
• Posterior external arcuate fibers originate from accessory cuneate
nucleus (positioned lateral to cuneate nucleus) to reach the cerebellum
through the inferior cerebellar peduncle.
14.
15. Rostral (open) medulla
• Inferior olivary nucleus is shown within prominence of the olive.
• It is present dorsolateral to the pyramid.
• Lateral to the medial lemniscus is the spinothalamic tract.
• The dorsal surface of open medulla forms part of the floor of the 4th
ventricle.
• Immediately deep to this floor lie a number of cranial nerve nuclei
(hypoglossal nucleus, dorsal motor nucleus of the vagus nerve
(nucleus ambiguus), and inferior and medial vestibular nuclei).
• Ventromedial to the hypoglossal nucleus close to the midline is the
medial longitudinal bundle which links vestibular with ocular nuclei.
• Dorsolateral prominence of open medulla is the inferior cerebellar
peduncle.
16.
17. CLINICAL NOTES
• Tumors of the posterior cranial fossa produce increased intracranial
pressure (ICP).
• There is a tendency to downward herniation of the medulla and
cerebellar tonsils through the foramen magnum.
• This will produce headache, neck stiffness and paralysis of the lower 4
cranial nerves owing to traction.
• In this condition lumbar puncture is contraindicated.
19. GROSS FEATURES
• The pons (bridge) connects the medulla to the midbrain.
• It is located ventral to the cerebellum where it bridges to connect the
two cerebellar hemispheres.
• The anterior surface shows many transverse pontine fibers that
converge on each side to form the middle cerebellar peduncle.
• The trigeminal nerve fibers emerge from the anterolateral surface
between the pons and its peduncle.
20. • In the groove between the pons and the medulla emerge the abducent,
the facial and the vestibulocochlear nerves.
• The posterior surface of the pons forms the upper half of the floor of
the 4th ventricle.
• It is divided into two halves by a median sulcus.
• Lateral to this sulcus is the facial colliculus produced by fibers of the
facial nerve winding around nucleus of the abducent nerve.
• Lateral to the facial colliculus is the vestibular area produced by
underlying vestibular nuclei.
22. INTERNAL STRUCTURES OF THE
PONS
Inferior level, level of facial colliculus.
Middle level, level of trigeminal nuclei.
Superior level, level of 4 lemnisci.
• For purposes of description the pons is divided into:
A posterior part, the tegmentum
An anterior part, the basis pontis.
23. • Basis pontis is marked by transversely oriented pontocerebellar
fibers originating from scattered pontine nuclei and pass to the
contralateral cerebellar hemisphere through the middle cerebellar
peduncle.
• Corticospinal fibers appear dispersed between fascicles of transverse
pontine fibers.
• Tegmentum pontis contains reticular formation, lemnisci and
cranial nerve nuclei.
24. Caudal Pons (level of facial colliculus)
• The trapezoid body is located ventral to ascending lemnisci but dorsal
to basis pontis.
• Beneath the floor of the 4th ventricle lie a number of cranial nerve
nuclei.
• Abducent nucleus is medially located and close to the surface.
• Facial motor nucleus is located ventrolateral to abducent nucleus.
• Fibers of facial nerve wind around abducent nucleus before exiting
from the ventral aspect of the pons.
25. • This creates the facial colliculus seen in the floor of the 4th ventricle.
• Laterally in the floor of the 4th ventricle is the vestibular area deep to
which are the superior and lateral vestibular nuclei.
• The cochlear nuclei are located more laterally posterior and anterior
to the inferior cerebellar peduncle.
• Lateral lemniscus of the auditory pathway is seen in the tegmentum
of the caudal pons.
26.
27. Mid Pons (level of trigeminal nuclei)
• The four trigeminal nuclei reach their maximum extent at this level
adjacent to the origin of the trigeminal nerve which exits from the
ventral aspect between the pons and its peduncle.
Rostral Pons (level of four lemnisci)
• The superior cerebellar peduncles form the lateral walls of the 4th
ventricle.
• The thin superior medullary velum spans between the superior
cerebellar peduncles to form roof of the 4th ventricle.
• The 4 lemnisci are organized in order as medial, spinal, trigeminal and
lateral forming crescent of lemnisci.
29. Functional significances of the pons
Contains cranial nerve nuclei: V,VI VII, and VIII.
Pathway for ascending and descending tracts.
Pathway for hearing.
Contains pontine reticular formation and superior salivatory nucleus.
Contains part of respiratory centers.
31. GROSS FEATURES
• The midbrain connects the pons and cerebellum with the forebrain.
• It is traversed with the cerebral aqueduct which connects the 3rd and
4th ventricles.
• On the ventral surface there is a depressed area called the
interpeduncular fossa bounded on each side by the crus cerebri.
• Oculomotor nerve fibers emerge from a groove on the medial side of
the crus cerebri.
• On the dorsal aspect there are 4 colliculi (4 corpora quadrigemina);
two superior and two inferior colliculi.
32. • The superior colliculi are centers for visual reflexes.
• The inferior colliculi are centers for auditory reflexes.
• In the midline below the colliculi the trochlear nerves emerge and
then wind around the lateral aspects of the midbrain to enter the
cavernous sinuses.
34. INTERNAL STRUCTURES
• The cerebral aqueduct divides the midbrain into posterior part,
tectum, and anterior part, the cerebral peduncle.
• The cerebral peduncle is divided by the substantia nigra into an
anterior part, crus cerebri, and a posterior part, the tegmentum.
• In the periaqueductal gray matter is nucleus of locus ceruleus
(noradrenergic nucleus).
• Moreover there is the raphe nucleus (serotonergic neurons).
• The tegmentum is bounded by the crus cerebri (cerebral peduncle)
which consists of descending cortical efferents.
35. • Its middle half is composed of corticobulbar (medially) and
corticospinal (laterally) fibers.
• On each side of the pyramidal tract are the corticopontine fibers.
• The most ventral part of the tegmentum is occupied by the substantia
nigra composed of pigmented neurons that synthesize dopamine.
• These neurons project to the corpus striatum.
• The inner structures of the midbrain are studied in two levels:
Caudal level, level of inferior colliculi.
Rostral level, level of superior colliculi.
36. Caudal Midbrain
• The inferior colliculus is part of the hearing system.
• At this level the ascending auditory fibers in the lateral lemniscus end
in the inferior colliculus.
• Lemniscal crescent is obvious at this level.
• Ventral to the periaqueductal gray matter lays the trochlear nucleus.
• The superior cerebellar peduncles decussate in the midline of this
level.
37. • Periaqueductal gray matter contains several nuclei:
Nucleus of locus ceruleus (noradrenergic/dopaminergic). This
nucleus extends to the pons and is concerned with cognitive mapping,
affective behavior, thalamic and neocortical activities.
Raphe nucleus (serotonergic).
Dorsal tegmental nucleus (secretes endorphins and enkephalins).
Close to this area is the central tegmental tract containing the
reticulothalamic tract (reticular activating system).
38.
39. Rostral Midbrain
• The superior colliculus is part of the visual system.
• Its afferents are mainly corticotectal fibers originating from the visual
cortex and the frontal eye field.
• These inputs are concerned with controlling movements of the eyes
(following objects, accommodation and conjugate eye movements).
• Efferents from the superior colliculi decussate in the dorsal tegmental
decussation and descend as tectospinal tract.
40.
41. • A small number of fibers of the optic tract terminate in the pretectal
nucleus, just rostral to the superior colliculus.
• The pretectal nucleus is connected to Edinger Westphal
(parasympathetic) nucleus to control papillary light reflexes.
• Ventral to the periaqueductal gray matter are the oculomotor nuclei.
• The central portion of the tegmentum is occupied by the red nucleus.
• Efferents from the red nucleus decussate in the ventral tegmental
decussation and descend as rubrospinal tract.
42. Functional significances of the midbrain
It contains cranial nerve nuclei: III and IV.
The cerebral aqueduct passes through it.
It offers pathway for the corticofugal fibers and the lemnisci.
The substantia nigra is considered part of the basal ganglia.
It has the red nucleus which is one of the extrapyramidal system.
It contains midbrain reticular formation.