Quiz 2
### Chapter 12: Nervous Tissue and Neurophysiology
1. Depolarization: This is the initial phase of an action potential where the inside of the neuron becomes less negative (more positive) due to the influx of sodium ions (Na+).
2. Relative Refractory Period: A period following an action potential when a neuron can fire another action potential but only with a stronger than normal stimulus.
3. Repolarization: The process of returning the membrane potential to its resting negative value after depolarization, mainly through the efflux of potassium ions (K+).
4. Absolute Refractory Period: A period immediately following an action potential during which a neuron cannot fire another action potential, regardless of the strength of the stimulus.
5. Ions Involved in Action Potential:
- Sodium (Na+): Influx causes depolarization.
- Potassium (K+): Efflux causes repolarization.
6. Graded Potentials: Small changes in membrane potential that can sum to generate an action potential if they reach the threshold.
7. IPSP vs. EPSP:
- Inhibitory Post-Synaptic Potential (IPSP): Hyperpolarizes the membrane, making it less likely to fire an action potential.
- Excitatory Post-Synaptic Potential (EPSP): Depolarizes the membrane, making it more likely to fire an action potential.
8. Axon Hillock: The region where the axon meets the cell body; critical in the initiation of action potentials.
9. Stimulus and Summation Types:
- Threshold Stimulus: Minimum level of stimulus required to generate an action potential.
- Spatial Summation: Multiple presynaptic neurons together release enough neurotransmitter to exceed the threshold.
- Temporal Summation: One presynaptic neuron releases neurotransmitters in rapid succession to exceed the threshold.
10. Hyperpolarization: The membrane potential becomes more negative than the resting potential.
11. Types of Neurons:
- Motor Neurons: Transmit signals from the CNS to muscles.
- Sensory Neurons: Transmit signals from sensory receptors to the CNS.
- Interneurons: Connect neurons within the CNS.
12. Types of Channels:
- Leakage Channels: Always open, allowing ions to "leak" across the membrane.
- Voltage-Gated Channels: Open or close in response to changes in membrane potential.
13. Neuron Classifications:
- Unipolar: Single process extending from the cell body.
- Bipolar: One axon and one dendrite.
- Multipolar: One axon and multiple dendrites.
### Chapter 13: Spinal Cord, Spinal Nerves, and Reflexes
1. Cross-Extensor Reflex: A reflex that helps maintain balance when the body shifts its weight, involves the extension of the opposite limb.
2. Stretch Reflex: Muscle contraction in response to stretching within the muscle, such as the knee-jerk reflex.
3. Plantar Reflex/Babinski Sign: Stroking the sole of the foot to observe toe movement; normal in infants but can indicate neurological issues in adults if toes fan out.
4. Golgi Tendon Reflex: Prevents muscles from over-contracting and causing damage by triggering muscle relaxation when tension is too high.
5. Reflex Arc: The neural pathway involved in a reflex action, consisting of a sensory neuron, an interneuron, and a motor neuron.
6. STM to LTM Transfer: The process by which short-term memories are consolidated into long-term memories.
7. Testing Cranial Nerves: Various tests to assess the functionality of cranial nerves, important for diagnosing neurological conditions.
8. Key Areas and Functions:
- Visceral Sensory Area: Processes information from internal organs.
- Olfactory Cortex: Processes smell information.
- Gustatory Cortex: Processes taste information.
- Vestibular Cortex: Processes balance and spatial orientation information.
- Primary Motor Cortex: Controls voluntary movements.
- Hippocampus: Important for memory formation.
- Amygdala: Involved in emotion processing.
- Broca’s Area: Involved in speech production.
- Wernicke’s Area: Involved in language comprehension.
9. Spinal Cord Structure:
- Ventral Root: Contains motor neurons.
- Dorsal Root: Contains sensory neurons.
- Ventral Horn: Contains motor neuron cell bodies.
- Dorsal Horn: Contains sensory neuron cell bodies.
- Medulla Oblongata: Regulates vital functions like heart rate and breathing.
### Chapter 15: Autonomic Nervous System
1. Acetylcholine (ACh) Release: Released by preganglionic neurons in both sympathetic and parasympathetic systems, and by postganglionic neurons in the parasympathetic system.
2. ANS Divisions:
- Sympathetic: Originates from the thoracolumbar region; prepares the body for "fight or flight".
- Parasympathetic: Originates from the craniosacral region; promotes "rest and digest" activities.
3. Receptor Types:
- Cholinergic Receptors: Respond to acetylcholine.
- Adrenergic Receptors: Respond to norepinephrine and epinephrine.
- Alpha Receptors: Typically cause vasoconstriction and increase blood pressure.
- Beta Receptors: Typically cause vasodilation and increase heart rate.
4. Effect of Drugs:
- Beta Blockers: Reduce blood pressure by blocking beta-adrenergic receptors.
- Alpha Blockers: Relax certain muscles and help small blood vessels remain open.
5. ANS Functions:
- Regulates involuntary functions such as heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal.