Nervous System Flashcards
(41 cards)
What is polarization in neurons?
The state when the inside of a neuron is more negatively charged (-70mV) compared to the outside, which is more positively charged.
What ions are in greater concentration in extracellular fluid compared to intracellular fluid?
Sodium ions
What ions are in greater concentration in intracellular fluid compared to extracellular fluid?
Potassium ions
What role do potassium channels play in neuron polarization?
They are open, allowing potassium ions to pass through freely.
What happens during depolarization?
Sodium channels open, allowing Na+ ions to enter the cell, reversing the polarity to +40mV.
What is the threshold level for a neuron to reach action potential?
-55mV
What occurs during repolarization?
Sodium channels close, potassium channels open, and sodium-potassium pumps restore membrane potential.
What is hyperpolarization?
A state where the intracellular fluid becomes more negative than the original resting potential, reaching -80mV.
What is the primary function of the nervous system?
To control actions of cells, tissues, organs, and systems toward homeostasis.
What are the basic functions of neurons?
Receive signals, process signals, and send signals to other neurons, muscles, or organs.
What is the role of dendrites in a neuron?
Receive impulses from sensory receptors or other neurons.
What is the function of the myelin sheath?
Insulates the axon and speeds up message transmission.
What are sensory neurons responsible for?
Responding to input from sensory organs and transmitting information to the central nervous system.
Where are motor neurons primarily located?
In the peripheral nervous system and spinal cord.
What is the function of glial cells?
Provide structural support, supply nutrients and oxygen, insulate neurons, and remove pathogens and dead neurons.
What is the central nervous system composed of?
The brain and spinal cord.
What is the role of the somatic nervous system?
Controls voluntary actions and communicates messages for muscle contractions.
What is the function of the autonomic nervous system?
Innervates internal organs, blood vessels, and glands for involuntary control.
What does the sympathetic nervous system do?
Prepares the body for emergency responses, activating ‘Fight or Flight.’
What is the role of the parasympathetic nervous system?
Restores homeostasis and promotes ‘Rest & Digest.’
What is the structure of the spinal cord?
Between 43-45 cm in length, protected by meninges and vertebrae, transmitting information throughout the body.
What does the cerebrum control?
Stores sensory information and initiates motor responses.
What is the main function of the frontal lobe?
Involved in reasoning, personality, movement, creativity, judgment, problem solving, and planning.
What does the temporal lobe process?
Auditory stimuli and is responsible for memory and emotions.
