All flashcards
Flashcard 1: Which receptor type binds ACh at the skeletal muscle neuromuscular junction?
Answer: Nicotinic acetylcholine receptor (nAChR). This ionotropic receptor triggers muscle contraction by allowing cation influx upon binding at the motor end plate.
Flashcard 2: What is the effect of opening ligand-gated Cl− channels on membrane potential?
Answer: Hyperpolarization (inhibitory postsynaptic potential, IPSP). Chloride influx shifts the membrane potential more negative, reducing the likelihood of action potential generation.
Flashcard 3: What is the primary immune-like phagocytic cell type in the CNS?
Answer: Microglia. These resident macrophages of the CNS engulf debris and pathogens to protect neural tissue.
Flashcard 4: What is the primary role of astrocytes in the CNS?
Answer: Support neurons and help maintain the blood-brain barrier. Astrocytes provide metabolic and structural support to neurons while regulating the extracellular environment and barrier integrity.
Flashcard 5: Which glial cells myelinate axons in the peripheral nervous system?
Answer: Schwann cells. These PNS glial cells individually myelinate axons, aiding in nerve regeneration and signal conduction.
Flashcard 6: Which glial cells myelinate axons in the central nervous system?
Answer: Oligodendrocytes. These CNS glial cells wrap multiple axons to form myelin sheaths, supporting rapid neural signaling.
Flashcard 7: What is the functional role of myelin in axons?
Answer: Increases conduction velocity by insulating the axon. Myelin sheaths prevent ion leakage and enable faster signal propagation via saltatory conduction along axons.
Flashcard 8: Which receptor class is activated by NE in most sympathetic target organs?
Answer: Adrenergic receptors (alpha and beta). These G-protein coupled receptors mediate sympathetic responses by binding catecholamines like NE in effector organs.
Flashcard 9: Which ANS division is associated with “fight-or-flight” physiology?
Answer: Sympathetic nervous system. This division mobilizes energy resources and prepares the body for emergency responses through widespread activation.
Flashcard 10: What is the correct ion movement that causes depolarization in a neuron?
Answer: Voltage-gated Na+ channels open; Na+ influx depolarizes. Threshold depolarization triggers sodium channel opening, allowing rapid sodium entry to reverse membrane potential.
Flashcard 11: What ion movement is primarily responsible for repolarization of the action potential?
Answer: Voltage-gated K+ channels open; K+ efflux repolarizes. Following peak depolarization, potassium channels open to restore the negative membrane potential through potassium outflow.
Flashcard 12: Identify the direction of neurotransmitter release across a chemical synapse.
Answer: From presynaptic axon terminal to postsynaptic membrane. Chemical synapses transmit signals unidirectionally via neurotransmitter diffusion across the synaptic cleft to receptor sites.
Flashcard 13: Which brain region is the primary homeostatic control center for autonomic and endocrine output?
Answer: Hypothalamus. This diencephalic structure integrates sensory inputs and regulates vital functions through neural and hormonal mechanisms.
Flashcard 14: What are the two major anatomical divisions of the nervous system?
Answer: Central nervous system and peripheral nervous system. The nervous system is anatomically divided into central components for processing and peripheral for communication with the body.
Flashcard 15: What structures make up the central nervous system (CNS)?
Answer: Brain and spinal cord. The CNS integrates sensory information and coordinates responses, consisting of protected neural tissues.
Flashcard 16: What structures make up the peripheral nervous system (PNS)?
Answer: Cranial nerves, spinal nerves, and ganglia. The PNS connects the CNS to the rest of the body, facilitating sensory input and motor output through neural bundles and clusters.
Flashcard 17: What is the functional difference between afferent and efferent neurons?
Answer: Afferent: sensory to CNS; efferent: motor from CNS. Afferent neurons transmit signals toward the CNS for integration, while efferent carry commands away to effectors.
Flashcard 18: What are the two main functional divisions of the efferent PNS?
Answer: Somatic nervous system and autonomic nervous system. Efferent PNS divisions separate voluntary control from involuntary regulation of internal functions.
Flashcard 19: What is the key difference between somatic and autonomic motor pathways?
Answer: Somatic: skeletal muscle; autonomic: smooth/cardiac/glands. Somatic pathways enable conscious control of movement, whereas autonomic regulate involuntary visceral functions.
Flashcard 20: What are the two divisions of the autonomic nervous system (ANS)?
Answer: Sympathetic and parasympathetic. The ANS is subdivided into antagonistic branches that balance physiological responses to stress and relaxation.
Flashcard 21: Which ANS division is associated with “rest-and-digest” physiology?
Answer: Parasympathetic nervous system. This division conserves energy and promotes maintenance activities like digestion during non-stressful states.
Flashcard 22: What is the neurotransmitter released by all preganglionic ANS neurons?
Answer: Acetylcholine (ACh). Preganglionic neurons in both ANS divisions use this neurotransmitter to synapse with postganglionic neurons at ganglia.
Flashcard 23: What neurotransmitter is typically released by sympathetic postganglionic neurons?
Answer: Norepinephrine (NE). Sympathetic postganglionic fibers primarily release this catecholamine to elicit fight-or-flight effects on target tissues.
Flashcard 24: What neurotransmitter is typically released by parasympathetic postganglionic neurons?
Answer: Acetylcholine (ACh). Parasympathetic postganglionic neurons release this neurotransmitter to mediate rest-and-digest responses in visceral organs.