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NEUROLOGY 2 MARKS : PART 14

THE POSTERIOR HORN CELL:

  • The posterior horn contains interneurons that make connections within the spinal cord as well as neurons that enter ascending sensory pathways.
  • It receives several types of sensory information from the body, including fine touch, proprioception, and vibration.
  • The dorsal horns contain the cell bodies of sensory neurons.
  • Posterior horn also called as posterior cornu, dorsal horn, spinal dorsal horn posterior horn.

ANTERIOR AND POSTERIOR SPINAL ROOT :

  • The dorsal root ( POSTERIOR SPINAL ROOT)  is the afferent sensory root and carries sensory information to the brain.
  • The ventral root ( ANTERIOR SPINAL ROOT) is the efferent motor root and carries motor information from the brain.
  • The difference between the dorsal and ventral roots of the spinal nerves are the sensory nerve fibers enter the spinal cord through the dorsal root while the motor nerves exit through the ventral root.

NEURALGIA:

  • Pain that travels along the length of a nerve. 
  • This compression is usually caused by a nearby blood vessel pressing on part of the nerve inside the skull. In cases like, trigeminal neuralgia can occur as a result of damage to the trigeminal nerve.
  • It’s a stabbing pain in the middle of the night. Symptoms can include a chronic prickling, tingling, or burning sensation  all day.
  • Uncontrolled nerve pain can be hard to bear. 

TRACTS:

  • The spinal cord has numerous groups of nerve fibers going towards and coming from the brain.
  • These have been collectively called the ascending and descending tracts of the spinal cord, respectively.
  • The tracts are responsible for carrying sensory and motor stimuli to and from the periphery .
  • The ascending tracts refer to the neural pathways by which sensory information from the peripheral nerves is transmitted to the cerebral cortex.

DORSAL COLUMN:

  • Fasciculus Gracilis
    • Fasciculus Cuneatus

LATERAL COLUMN:

  • Lateral Spinothalamic tract
  • Dorsal Spinocerebellar tract
  • Ventral Spinocerebellar tract
  • Spinotectal tract
  • Spinoreticular fibers
  • Spino-olivary pathway
  • Spinovestibular tract

VENTRAL COLUMN:

  • Anterior Spinothalamic tract.

DESCENDING TRACTS OF THE SPINAL CORD:

  • ·        Corticospinal Tracts
  • ·        Vestibulospinal Tract
  • ·        Rubrospinal Tract
  • ·        Reticulospinal Tracts
  • ·        Tectospinal Tract

THE COUGH REFLEX:

  • The cough reflex serves to prevent the entry of harmful substances into the tracheobronchial tree and to expel excess secretions and retained material from the tracheobronchial tree.
  • Cough begins with stimulation of cough receptors, located in the upper and lower airways, and in many other sites such as the ear canal, tympanic membrane, sinuses, nose, pericardium, pleura, and diaphragm.
  • Receptors send messages via vagal, phrenic, glossopharyngeal, or trigeminal nerves to the “cough center,” which is in the medulla. 

THE SWALLOWING REFLEX:

  • The swallowing reflex is one phase of the swallow which is under reflexive or involuntary control.
  • This stage of the swallow begins after food which has been masticated has been gathered together in the mouth and formed into a bolus which is passed from the posterior tongue through the faucial arches.
  • The swallowing process was classified into oral, pharyngeal, and esophageal stages according to the location of the bolus.
  • The oral stage was later subdivided into oral preparatory and oral propulsive stages.

WHAT IS THE SALIVARY REFLEX?

  • Salivary gland secretion is a nerve-mediated reflex and the volume of saliva secreted is dependent on the intensity and type of taste and on chemosensory, masticatory or tactile stimulation.
  • Saliva is secreted in response to taste and somatosensory oral stimulation. Because salivary secretion is solely initiated in response to activation of the autonomic nerve supply to the salivary glands, sensory information from the oral cavity must form the afferent limb of this reflex.
  • Salivary glands are innervated, either directly or indirectly, by the parasympathetic and sympathetic arms of the autonomic nervous system.
  • Parasympathetic stimulation evokes a copious flow of saliva.

THE SUCKING REFLEX:

  • The sucking reflex is probably one of the most important reflexes your newborn has.
  • It is paired with the rooting reflex, in which a newborn searches for a food source.
  • When they find it, the sucking reflex allows them to suck and swallow the milk.
  • The sucking reflex is one of seven natural reflexes newborns have, including the Moro reflex, the grasping reflex, the rooting reflex, the stepping reflex, the fencing reflex, and the Babinski reflex. 

VOMITING REFLEX:

  • Vomiting is the forceful expulsion of contents of the stomach and often, the proximal small intestine.
  • There are three steps in the vomiting reflex .
  • First -Nausea develops. Second-retching occurs as a result of activation of spasmodic contractions of the diaphragm and intercostal muscles combined with closure of the glottis.
  • Third- the act of vomiting occurs.
  • Vomiting can serve the function of emptying a noxious chemical from the gut, and nausea appears to play a role in a conditioned response to avoid ingestion of offending substances.

CATHERINE SHALINI RAJA
M.P.T.,MIAP.,PGDYN
CARDIO RESPIRATORY PHYSICAL THERAPIST
FITNESS & SPORTS REHABILITATION SPECIALIST.

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NEUROLOGY 2 MARKS : PART 13

MECHANORECEPTORS & CHEMORECEPTORS:

  • Mechanoreceptors are receptors in the skin and on other organs that detect sensations of touch.
  • They are called mechanoreceptors because they are designed to detect mechanical sensations or differences in pressure.
  • Nociceptors, mechanoreceptors, chemoreceptors, thermoreceptors, and photoreceptors are types of sensory receptors (sensory neurons) located in different areas of the body.
  •  Mechanoreceptors are a type of sensory receptor that are activated and respond to mechanical pressure.

5 TYPES OF SENSORY RECEPTORS:

  • Phemoreceptors- stimulated by changes in the chemical concentration of substances.
  • Pain receptors-stimulated by tissue damage.
  • Thermoreceptors- stimulated by changes in temperature.
  • Mechanoreceptors- stimulated by changes in pressure or movement.
  • Photoreceptors- stimulated by light energy.

MUSCLE SPINDLE:

  •  Muscle spindles are stretch receptors within the body of a muscle that primarily detect changes in the length of the muscle.
  • They convey length information to the central nervous system via afferent nerve fibers.
  • The responses of muscle spindles to changes in length also play an important role in regulating the contraction of muscles, by activating motor neurons via the stretch reflex to resist muscle stretch.
  • Proprioceptors are specialized sensory receptors that are located within joints, muscles, and tendons.

THE GOLGI TENDON ORGAN  :

  • The Golgi tendon organ (GTO) (also called Golgi organ, tendon organ, neurotendinous organ or neurotendinous spindle) is a proprioceptive sensory receptor organ that senses changes in muscle tension.
  • The golgi tendon organ is a proprioceptor, sense organ that receives information from the tendon, that senses TENSION.
  • If there is too much muscle tension thegolgi tendon organ will inhibit the muscle from creating any force  thus protecting  from injuring itself.

PHYSIOLOGICAL CLASSIFICATION OF REFLEXES:

  • Stretch (knee-jerk, patellar) reflex.
  • Withdrawal (flexor) reflex.
  • Crossed-extensor reflex.

CLASSIFICATION OF CLINICAL REFLEXES:

  • Superficial reflex
  • Deep reflexes
  • Visceral reflexes
  • Pathological reflexes.

ANATOMICAL CLASSIFICATIONS:

  • Segmental reflex
  • Intersegmental  reflex
  • Suparsegmental reflex

CLONUS:

  • Clonus is a neurological condition that occurs when nerve cells that control the muscles are damaged.
  • This damage causes involuntary muscle contractions or spasms.
  • Clonus is a neurological condition that occurs when nerve cells that control the muscles are damaged. 
  • Clonus may be found at the ankle, patella, triceps surae, wrist, jaw, biceps brachii.
  • Damaged nerves can cause muscles to misfire, leading to involuntary contractions, muscle tightness, and pain.
  • Clonus can cause a muscle to pulse for an extended period. This pulsing can lead to muscle fatigue, which may make it difficult for a person to use the muscle later.

MONOSYNAPTIC AND POLYSYNAPTIC:

  • Monosynaptic refers to the presence of a single chemical synapse.
  • Monosynaptic reflex is a simple reflex that involves transmission of information from asensory neuron to the appropriate motor neuron across a single synapse in thespinal cord. 
  • By contrast, in polysynaptic reflex arcs, one or more interneurons connect afferent (sensory) and efferent (motor) signals.
  • The knee-jerk reflex is considered a monosynaptic reflex because it involves direct connections between sensory neurons and motor neurons, without any neurons in between.

MYOTOMES AND DERMATOMES:

  • Myotomes and dermatomes are a part of the somatic (voluntary) nervous system, which is part of the peripheral nervous system.
  • A dermatome is an area of skin supplied by sensory neurons that arise from a spinal nerve ganglion.
  • Each dermatome represents the sensory innervation of a particular spinal nerve.
  • Myotomes is  a group of muscles innervated by a single spinal nerve.

CAUSALGIA:

  • Causalgia is technically known as complex regional pain syndrome type II (CRPS II).
  • It’s a neurological disorder that can produce long-lasting, intense pain.
  • Causalgia is usually caused by brachial plexus injuries, involving nerves that run from the neck to the arm.
  • The disruption of neural signals causes pain and increased release of the neurotransmitter norepinephrine.
  • Research supports that there is no causal relationship between depression, anxiety, anger and sleep disorders, and CRPS.

ANTERIOR HORN CELLS:

  • Anterior horn cells (α-motor neurons), located in the anterior gray matter of the spinal cord, are found at every segment and are concentrated in the cervical and lumbosacral enlargements.
  • The lower motor neuron includes the anterior horn cell (motor neuron), nerve, neuromuscular junction, and muscle. 
  • Cell bodies are located in anterior horn of the spinal cord.

CATHERINE SHALINI RAJA
M.P.T.,MIAP.,PGDYN
CARDIO RESPIRATORY PHYSICAL THERAPIST
FITNESS & SPORTS REHABILITATION SPECIALIST.

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NEUROLOGY 2 MARKS : PART 12

NEURON:

  • A nerve cell that receives and sends electrical signals over long distances within the body.
  • neuron receives electrical input signals from sensory cells (called sensory neurons) and from other neurons.
  • A neuron that simply signals another neuron is called an interneuron.
  • Neurons are divided into four major types: unipolar, bipolar, multipolar, and pseudounipolar. Unipolar neurons have only one structure extending from the soma.
  • Bipolar neurons have one axon and one dendrite extending from the soma.
  • Neurons (also known as neurones, nerve cells and nerve fibers) are electrically excitable cells in the nervous system that function to process and transmit information

REFLEX:

  • Reflexes, or reflex actions, are involuntary, almost instantaneous movements in response to a specific stimulus.
  •  Reflex arcs that contain only two neurons, a sensory and a motor neuron, are considered monosynaptic. 
  • Examples of monosynaptic reflex arcs in humans include the patellar reflex and the Achillesreflex.
  • Reflex tests are performed as part of a neurological exam, either a mini-exam done to quickly confirm integrity of the spinal cord or a more complete exam performed to diagnose the presence and location of spinal cord injury or neuromusculardisease. Deep tendon reflexes are responses to muscle stretch.

AFFERENT AND EFFERENT:

  • Neurons that receive information from our sensory organs (e.g. eye, skin) and transmit this input to the central nervous system are called afferent neurons.
  • Neurons that send impulses from the central nervous system to your limbs and organs are called efferent neurons.
  • Afferent” and “efferent” are not different types of neurons, they are terms for pathways that connect a neuron or brain area with other brain areas. 
  • Afferent to a given brain area are connections that bring signals into it, efferent are connections that carry signals out of it.

DOPAMINE:

  • Dopamine is a neurotransmitter, a chemical responsible for sending messages between the brain and different nerve cells of the body.
  • In the brain, dopamine functions as a neurotransmitter, a chemical released by neurons (nerve cells) to send signals to other nerve cells.
  • The brain includes several distinct dopamine pathways, one of which plays a major role in the motivational component of reward-motivated behavior.
  • Dopamine is a major transmitter in the extrapyramidal system of the brain, and important in regulating movement .

ATP:

  • ATP stands for adenosine triphosphate.
  • ATP is the principal molecule for storing and transferring energy in cells. ATPs are used as the main energy source for metabolic functions.
  • ATP is an adenine nucleotide bound to three phosphates.
  • There is a lot of energy stored in the bond between the second and third phosphate groups that can be used to fuel chemical reactions.
  • The process of phosphorylating ADP to form ATP and removing a phosphate fromATP to form ADP in order to store and release energy respectively is known as the ATP cycle.

SEROTONIN :

  • Serotonin is a neurotransmitter. Its chemical name is 5-Hydroxytryptamine or 5-HT.
  • It is derived from tryptophan. 
  • Serotonin is found in all vertebrates, mainly in the gastrointestinal tract, blood platelets and central nervous system.
  • As a neurotransmitter, serotonin helps to relay messages from one area of the brain to another.
  • This includes brain cells related to mood, sexual desire and function, appetite, sleep, memory and learning, temperature regulation, and some social behavior.
  • There may be a link between serotonin and depression.
  • If so, it is unclear whether low serotonin levels contribute to depression, or if depression causes a fall in serotonin levels.

SYNAPSE:

  • The function of the synapse is to transfer electric activity (information) from one cell to another.
  • The transfer can be from nerve to nerve (neuro-neuro), or nerve to muscle (neuro-myo).
  • The region between the pre- and postsynaptic membrane is very narrow.

THERE ARE TWO TYPES OF SYNAPSES:

  • Electrical synapses.
  • Chemical synapses.

NEUROMUSCULAR JUNCTION  :

  • A neuromuscular junction (or myoneural junction) is a chemical synapse formed by the contact between a motor neuron and a muscle fiber.
  • It is at the neuromuscular junction that a motor neuron is able to transmit a signal to the muscle fiber, causing muscle contraction.
  • The neuromuscular junction is a type of synapse where neuronal signals from the brain or spinal cord interact with skeletal muscle fibers, causing them to contract.
  • It is at the neuromuscular junction that a motor neuron is able to transmit a signal to the muscle fiber, causing muscle contraction.
  • Muscles require innervation to function and to maintain muscle tone, avoiding atrophy.

NEUROMUSCULAR JUNCTION  :

  • A neuromuscular junction (or myoneural junction) is a chemical synapse formed by the contact between a motor neuron and a muscle fiber.
  • It is at the neuromuscular junction that a motor neuron is able to transmit a signal to the muscle fiber, causing muscle contraction.
  • The neuromuscular junction is a type of synapse where neuronal signals from the brain or spinal cord interact with skeletal muscle fibers, causing them to contract.
  • It is at the neuromuscular junction that a motor neuron is able to transmit a signal to the muscle fiber, causing muscle contraction.
  • Muscles require innervation to function—and even just to maintain muscle tone, avoiding atrophy.

CATHERINE SHALINI RAJA
M.P.T.,MIAP.,PGDYN
CARDIO RESPIRATORY PHYSICAL THERAPIST
FITNESS & SPORTS REHABILITATION SPECIALIST.

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NEUROLOGY 2 MARKS : PART 11

  • CENTRAL NERVOUS SYSTEM:
  • Central nervous system (CNS): The central nervous system is that part of the nervous system that consists of the brain and spinal cord.
  • The brain plays a central role in the control of most bodily functions, including awareness, movements, sensations, thoughts, speech, and memory.
  • The spinal cord is connected to a section of the brain called the brainstem and runs through the spinal canal.
  • Cerebrospinal fluid surrounds the brain and the spinal cord and also circulates within the cavities (called ventricles) of the central nervous system.
  • PERIPHERAL NERVOUS SYSTEM (PNS) :
  • The peripheral nervous system (PNS) is the division of the nervous system containing all the nerves that lie outside of the central nervous system (CNS). The Primary role of the PNS is to connect the CNS to the organs, limbs, and skin.
  • The peripheral nervous system (PNS) connects the central nervous system (CNS) to sensory organs such as the eye and ear, other organs of the body, muscles, blood vessels and glands.
  • The peripheral nerves include the 12 cranial nerves.
  • Voluntary control – the nerves that carry instructions from your brain to your limbs.
  • NAME THE 12 PAIRS OF CRANIAL NERVES:
  1. I Olfactory (Smell)
  2. II Optic (Sight)
  3. III Oculomotor (Moves eyelid and eyeball and adjusts the pupil and lens of the eye)
  4. IV Trochlear (Moves eyeballs)
  5. V Trigeminal (Facial muscles incl. chewing; Facial sensations)
  6. VI Abducens (Moves eyeballs)
  7. VII Facial (Taste, tears, saliva, facial expressions)
  8. VIII Vestibulocochlear (Auditory)
  9. IX Glossopharyngeal (Swallowing, saliva, taste)
  10. X Vagus (Control of PNS e.g. smooth muscles of GI tract)
  11. XI Accessory (Moving head & shoulders, swallowing)
  12. XII Hypoglossal (Tongue muscles – speech & swallowing)
  • HOW MANY PAIRS OF SPINAL NERVES:
  1. 8 pairs of cervical nerves (C1-C8)
  2. 12 pairs of thoracic nerves (T1 – T12)
  3. 5 pairs of lumbar nerves (L1-L5)
  4. 5 pairs of sacral nerves (S1-S5)
  5. 1 pair of coccygeal nerves (Co1)
  • MEDULLA OBLONGATA:
  • The medulla oblongata helps regulate breathing, heart and blood vessel function,digestion, sneezing, and swallowing.
  • This part of the brain is a center forrespiration and circulation. 
  • Sensory and motor neurons (nerve cells) from the forebrain and midbrain travel through the medulla.
  • If the medulla oblongata or the nerves that pass through it are injured or damaged, May experience paralysis or loss of muscle coordination. lose your sense of touch, develop vertigo or have trouble swallowing.
  • PONS:
  • Besides the medulla oblongata,  brainstem also has a structure called the pons.
  • The pons is a major structure in the upper part of your brainstem.
  • It is involved in the control of breathing, communication between different parts of the brain, and sensations such as hearing, taste, and balance.
  • Damage to the pons can result in serious problems as this brain area is important for connecting areas of the brain that control autonomic functions and movement.
  • Locked-in syndrome is a condition resulting from damage to nerve pathways in the pons that connect the cerebrum, spinal cord, and cerebellum.
  • CEREBELLUM:
  • The cerebellum is located behind the top part of the brain stem.
  • The cerebellum coordinates voluntary movements such as posture, balance, coordination, and speech, resulting in smooth and balanced muscular activity. 
  • The cerebellum receives information from the sensory systems, the spinal cord, and other parts of the brain and then regulates motor movements.
  • BASAL GANGLIA:
  • The basal ganglia are a collection of nuclei found on both sides of the thalamus, outside and above the limbic system, but below the cingulate gyrus and within the temporal lobes.
  • Basal ganglia are strongly interconnected with the cerebral cortex, thalamus, and brainstem, as well as several other brain areas.
  • The basal ganglia are associated with a variety of functions, including control of voluntary motor movements, procedural learning, habit learning, eye movements, cognition, and emotion.
  • HYPOTHALAMUS:
  • The hypothalamus is a small region of the brain. It’s located at the base of the brain, near the pituitary gland.
  • While it’s very small, the hypothalamus plays a crucial role in many important functions, including: releasing hormones. regulating body temperature.

Hormones of the Hypothalamus

  • Thyrotropin-releasing hormone (TRH)
  • Gonadotropin-releasing hormone (GnRH)
  • Growth hormone-releasing hormone (GHRH)
  • Corticotropin-releasing hormone (CRH)
  • Somatostatin.
  • Dopamine.

MENINGES:

  • The main functions of the meninges include: Protecting the brain and spinal cord form mechanical injury.
  • Providing blood supply to the skull and to the hemispheres. Providing a space for the flow of cerebrospinal fluid.
  • There are three layers of meninges around the brain and spinal cord.
  • The outer layer, the dura mater, is tough, white fibrous connective tissue.
  • The middle layer of meninges is arachnoid, a thin layer resembling a cobweb with numerous threadlike strands attaching it to the innermost layer.

CATHERINE SHALINI RAJA
M.P.T.,MIAP.,PGDYN
CARDIO RESPIRATORY PHYSICAL THERAPIST
FITNESS & SPORTS REHABILITATION SPECIALIST.

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NEUROLOGY- 2 MARKS- PART 10

1. Spasticity :

  • Spasticity means increased muscle tone. 
  • It is a condition inwhich certain muscles are continuously contracted.
  • This contraction cause stiffness or tightness of the muscles. 
  • It’s usually caused bydamage to the portion of the brain or spinal cord that control voluntary movement.
  • Spasticity affects more than an estimated 12 million people world wide .

2. Rigidity :

  • Rigidity is an increase in muscle tone leading to a resistance to passive movement through out the Range of motion 

3.Signs and Symptoms of Quadriplegia :

  •  loss of movement 
  • Loss of sensation 
  • Loss of bowel or bladder control 
  • Changes in sexual functions
  • Difficulty in  breathing ,coughing 
  • Difficulty to Balance and walking 
  • Numbness,tingling 
  • Extreme back pain.

4.Athetosis :

  • Athetosis is amovement dysfunction 
  • It is characterized byslow, involuntary writhing movements of fingers, hands, toes and feet 
  • Movements of Athetosisare sometimes called Athetoid movements 
  • This movements may becontinuous slow and rolling 
  • They may also makemaintaining a symmetrical and stable posture difficult .

5.Intracranial pressure : 

  • ICP is the inside theskull and thus is the brain tissue and cerebralspinal fluid (CSF) 
  • ICP is measured inmillimeters of mercury (mmHg) and at rest, is normally 7-5mmHg supineadult 
  • Increased ICP is alife-threatening condition 

6.Myelitis :

  •  Myelitis is inflammation of the spinal cord which can disrupt the normal response from thebrain to the rest of the body and from the rest of the body to the brain.
  • It can cause the Myelin and axon to be damaged resulting in symptoms such as paralysis ofsensory loss

  Types of myelitis: 

 1. Acute flaccid myelitis 

 2. Poliomyelitis 

 3. Transverse myelitis.

7.Dysphagia :

  • Dysplagia is definedas an inefficient of transferring food , liquid , or saliva from the Orelcavity to the stomach 
  • And there isdifficulty in swalloing
  • These is  theprominent symptoms in patients with esoinophilic , esophagitis 
  • In Dysplagia there aredificulty in the feeding, gagging, irritability and vomiting 

8.Chorea :

  • The term chorea isderived from the ancient Greek 
  • It’s an abnormalinvoluntary movement disorder called dyskinesias (one of a group ofneurological disorder) 
  • There are quickmovements of feet or hard or comparable to dancing 

9.Tremor :

  •  Tremor is aninvoluntary rhymemic, muscle contraction leading to shaking movement in one ormore parts of the body 
  • Mostly affects thehands, arms, head, vocal cord, toes, and legs 
  • Tremor may beintermittent or constant 
  • It’s affects both maleand female 
  • Most common amongmiddle aged and older aged adults 

10. Types of spinabifida :

  • There are fourtypes 
  •    Occulta 
  •    Closedneural tube defects 
  •     Meningocele
  •     Myelomeningocele.
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