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.

ANATOMY: 2MARKS PART-1

1.Synovial Fluid:

The Joints In The Human Body Contains Synovial Fluid. This Fluid Is A Thick Liquid That Lubricates The Joint And Allows For Ease Of Movement. In Joint Diseases Like Arthritis, The Synovium Of The Joint Is The Main Place Where Inflammation Occurs. Limited Mobility In The Joint, Or Pain And Stiffness With Movement, Are Often The First Signs Of Joint Disorders. Synovial Fluid And Joint Inflammation Are More Common We Grow Older. Continue reading “ANATOMY: 2MARKS PART-1”