Untitled Flashcards Set

Functions of the Nervous System

1. What are the three main functions of the nervous system?

   • Sensory input (gathering information), integration (processing information), and motor output (responding to stimuli).

2. How does the nervous system maintain homeostasis?

   • It regulates body functions such as heart rate, breathing, and temperature by receiving and responding to internal and external stimuli.

3. What is the difference between the central nervous system (CNS) and the peripheral nervous system (PNS)?

   • The CNS consists of the brain and spinal cord, while the PNS includes all the nerves outside the CNS that connect it to the rest of the body.

4. What are the two divisions of the autonomic nervous system, and how do they function?

   • The sympathetic division prepares the body for "fight or flight" responses, while the parasympathetic division promotes "rest and digest" functions.

5. How does sensory input travel through the nervous system to produce a response?

   • Sensory receptors detect a stimulus → sensory neurons send signals to the CNS → the CNS processes the information → motor neurons send signals to muscles or glands to respond.

Neuroglia (Glial Cells)

6. What are neuroglia, and how do they differ from neurons?

   • Neuroglia are support cells that nourish, protect, and assist neurons. Unlike neurons, they do not transmit electrical impulses.

7. Name the four types of neuroglia in the CNS and their functions.

   • Astrocytes: Maintain the blood-brain barrier and provide structural support.

   • Oligodendrocytes: Produce myelin to insulate CNS neurons.

   • Microglia: Act as immune cells, removing waste and pathogens.

   • Ependymal cells: Line brain ventricles and help circulate cerebrospinal fluid (CSF).

8. Name the two types of neuroglia in the PNS and their functions.

   • Schwann cells: Produce myelin for PNS neurons.

   • Satellite cells: Support and protect neuron cell bodies in ganglia.

9. What is the function of astrocytes in the CNS?

   • They maintain the blood-brain barrier, provide nutrients to neurons, and regulate the extracellular environment.

10. How do oligodendrocytes and Schwann cells differ in their roles?

    • Oligodendrocytes myelinate multiple CNS axons, while Schwann cells myelinate only one axon in the PNS.

11. What role do microglia play in the nervous system?

    • They act as the brain’s immune cells by removing debris, dead cells, and pathogens.

12. How do ependymal cells contribute to cerebrospinal fluid (CSF) circulation?

    • They line the ventricles of the brain and use cilia to help circulate CSF, which cushions and nourishes the brain and spinal cord.

Neurons

13. What are the three main parts of a neuron, and what are their functions?

    • Dendrites (receive signals), cell body (soma) (processes information), and axon (transmits impulses to other neurons or muscles).

14. Explain the difference between sensory neurons, motor neurons, and interneurons.

    • Sensory neurons carry signals from sensory receptors to the CNS.

    • Motor neurons transmit commands from the CNS to muscles or glands.

    • Interneurons connect neurons within the CNS for processing and response.

15. What is the function of the myelin sheath, and how does it affect nerve impulses?

    • It insulates axons, increasing the speed of electrical signal transmission.

16. Describe how an action potential is generated and propagated along a neuron.

    • When a neuron reaches a threshold, sodium (Na⁺) channels open, causing depolarization. The impulse travels along the axon as ion channels open in sequence, followed by repolarization as potassium (K⁺) exits the neuron.

17. What is the role of neurotransmitters in neural communication?

    • Neurotransmitters are chemical messengers that transmit signals across synapses between neurons.

18. What is the synapse, and how does signal transmission occur across it?

    • A synapse is the gap between two neurons. When an electrical signal reaches the axon terminal, neurotransmitters are released into the synaptic cleft and bind to receptors on the next neuron.

19. What is the difference between excitatory and inhibitory neurotransmitters?

    • Excitatory neurotransmitters increase the likelihood of an action potential (e.g., glutamate), while inhibitory neurotransmitters decrease it (e.g., GABA).

20. How does damage to neurons affect nervous system function?

    • Damage can disrupt signal transmission, leading to neurological disorders, paralysis, memory loss, or sensory impairment.