Anatomy and Physiology: Brain and Nuero

In-Depth Flashcards: Nervous System, Action Potential, and Synapse

  • Nervous System: Overview of the central and peripheral nervous systems, their functions, and major components.

  • Action Potential: Detailed explanation of the generation and propagation of action potentials in neurons, including ion channels and membrane potential changes.

  • Synapse: Examination of synaptic transmission, including neurotransmitter release, receptor binding, and the effects on post-synaptic neurons.

1. Fundamentals and Divisions of the Nervous System

Flashcard 1

Q: What is the primary function of the nervous system? A: The nervous system is the master controlling and communicating system of the body, responsible for every thought, action, and emotion.

Flashcard 2

Q: What are the three overlapping functions of the nervous system? A:

  1. Sensory input: Information received from inside and outside the body via sensory receptors.

  2. Integration: Processing and interpreting sensory inputs to decide on an action.

  3. Motor output: Activation of effector organs (muscles and glands) to respond.

Flashcard 3

Q: What are the two main divisions of the nervous system? A:

  1. Central Nervous System (CNS): Brain and spinal cord, serving as the integrating and control center.

  2. Peripheral Nervous System (PNS): Nerves outside the CNS, connecting the brain and spinal cord to the rest of the body.

Flashcard 4

Q: What are the two functional subdivisions of the PNS? A:

  1. Sensory (Afferent) Division: Transmits impulses to the CNS from sensory receptors.

  2. Motor (Efferent) Division: Sends impulses from the CNS to effector organs.

2. Histology of the Nervous System

Flashcard 5

Q: What are the two types of cells in the nervous system and their functions? A:

  1. Neurons: Conduct nerve impulses.

  2. Neuroglia (Glial Cells): Support, insulate, and protect neurons.

Flashcard 6

Q: Name the functional classifications of neurons. A:

  1. Sensory (Afferent) Neurons: Transmit stimuli to the CNS.

  2. Motor (Efferent) Neurons: Transmit impulses from the CNS to muscles and glands.

  3. Interneurons: Process and store information; shuttle signals between motor and sensory neurons.

Flashcard 7

Q: What are the components of a neuron? A:

  • Cell Body: Contains the nucleus and cytoplasm.

  • Dendrites: Short, branched extensions that receive signals.

  • Axon: Long extension that transmits impulses away from the cell body.

Flashcard 8

Q: What is the difference between myelinated and unmyelinated fibers? A:

  • Myelinated Fibers: Have a myelin sheath, increasing the speed of nerve impulses.

  • Unmyelinated Fibers: Lack a myelin sheath and conduct impulses more slowly.

3. Membrane Potential and Action Potentials

Flashcard 9

Q: Define resting membrane potential. A: The difference in electrical charges inside and outside a resting neuron, typically ranging from -40mV to -90mV.

Flashcard 10

Q: What triggers an action potential (AP)? A: When the membrane potential reaches the threshold of approximately -55mV, triggering depolarization.

Flashcard 11

Q: Describe the phases of an action potential. A:

  1. Depolarization: Sodium channels open; Na+ enters the cell.

  2. Repolarization: Potassium channels open; K+ exits the cell.

  3. Hyperpolarization: Excess K+ exits, making the inside more negative than the resting state.

Flashcard 12

Q: What is the "all-or-nothing" principle of an AP? A: An action potential either fully occurs or not at all, depending on whether the threshold is reached.

4. Synapses

Flashcard 13

Q: What are synapses? A: Specialized junctions mediating the transfer of information between neurons.

Flashcard 14

Q: Name the two types of synapses. A:

  1. Electrical Synapses: Use gap junctions for direct ion flow, allowing faster communication.

  2. Chemical Synapses: Use neurotransmitters to cross a synaptic cleft between neurons.

Flashcard 15

Q: Describe the stages of an AP crossing a chemical synapse. A:

  1. AP arrives at the presynaptic terminal.

  2. Voltage-gated calcium channels open, allowing calcium to enter.

  3. Neurotransmitters are released via exocytosis.

  4. Neurotransmitters bind to receptors on the postsynaptic membrane.

  5. Ion channels open, generating a postsynaptic potential.

  6. If depolarization reaches the threshold, an AP is initiated in the postsynaptic neuron.

Flashcard 16

Q: What are the main parts of a chemical synapse? A:

  1. Presynaptic Axon Terminal: Releases neurotransmitters.

  2. Synaptic Vesicles: Contain neurotransmitters.

  3. Postsynaptic Membrane: Contains receptors for neurotransmitters.

Flashcard 17

Q: What happens after neurotransmitter release? A:

  • Neurotransmitters diffuse across the synaptic cleft and bind to ligand-gated channels.

  • Ion flow causes depolarization or hyperpolarization, depending on the neurotransmitter and receptor.

Flashcard 18

Q: How is neurotransmitter activity terminated? A:

  1. Reuptake: Neurotransmitter is reabsorbed by the presynaptic neuron.

  2. Degradation: Enzymes break down the neurotransmitter.

  3. Diffusion: Neurotransmitter diffuses away from the synaptic cleft.

Flashcard 19

Q: What is the significance of calcium in synaptic transmission? A: Calcium triggers the release of neurotransmitters by causing synaptic vesicles to fuse with the presynaptic membrane.

Flashcard 20

Q: What is the role of ligand-gated channels in the postsynaptic neuron? A: They open in response to neurotransmitter binding, allowing ions to flow and generate a graded potential.

Flashcard 21

Q: What determines if the postsynaptic neuron generates an AP? A: Whether the graded potential reaches the threshold at the axon hillock.

5. Clinical Applications

Flashcard 22

Q: What is multiple sclerosis (MS)? A: An autoimmune disorder where the immune system attacks myelin in the CNS, disrupting nerve communication.

Flashcard 23

Q: How does the rabies virus affect the nervous system? A: The virus travels via axonal transport to the CNS, causing inflammation, delirium, and death if untreated.

Flashcard 24

Q: What is Guillain-Barré syndrome (GBS)? A: A rare autoimmune disorder in which the immune system attacks the myelin sheath in the peripheral nervous system, causing muscle weakness and paralysis.

Flashcard 25

Q: What is amyotrophic lateral sclerosis (ALS)? A: A neurodegenerative disorder that affects motor neurons in the brain and spinal cord, leading to muscle weakness and atrophy.

Flashcard 26

Q: How does Parkinson's disease affect the nervous system? A: It is caused by the degeneration of dopamine-producing neurons in the brain, leading to tremors, rigidity, and difficulty with movement.

Flashcard 27

Q: What is epilepsy? A: A neurological disorder characterized by recurrent seizures, caused by abnormal electrical activity in the brain.

Flashcard 28

Q: How does traumatic brain injury (TBI) affect the brain? A: TBIs can cause concussions, contusions, hemorrhages, or cerebral edema, leading to various levels of functional impairment.

Flashcard 29

Q: What is neuroplasticity? A: The brain's ability to reorganize itself by forming new neural connections to compensate for injury or disease.

This flashcard set comprehensively covers the nervous system, its functions, and related processes. Let me know if you'd like further refinement!