Structures
The human nervous system senses and responds to changes in the ____________ and ____________ environment.
What are the internal and external environments?
The resting membrane potential of a neuron is approximately ____________.
What is -70 millivolts (mV)?
This type of feedback loop amplifies or reinforces a change in the body
What is a positive feedback loop?
The three main parts of the nervous system are the ____________, ____________, and ____________.
What are the brain, spinal cord, and nerves?
During depolarization, this ion rushes into the neuron.
What is sodium (Na⁺)?
This is the stimulus that begins the positive feedback loop during childbirth, leading to uterine contractions.
What is the stretching of the uterus?
The division of the nervous system that controls voluntary movement is the ____________ system.
What is the somatic system?
This is the phase during an action potential when potassium (K⁺) exits the neuron, restoring the negative membrane potential.
What is repolarization?
The neural pathway responsible for a rapid, involuntary response, involving sensory neurons, interneurons, and motor neurons.
What is a reflex arc?
These two types of cells make up nervous tissue.
What are neurons and glial cells?
This insulating layer around some axons speeds up nerve impulse transmission.
What is the myelin sheath?
During childbirth, this hormone is released as part of a positive feedback loop to increase the strength of uterine contractions.
What is oxytocin?
The peripheral nervous system sends ____________ messages to the CNS and ____________ messages from the CNS to muscles and glands.
What are sensory and motor messages?
The transmission of an impulse across a synapse requires these chemical messengers.
What are neurotransmitters?
In a reflex arc, the correct order of neurons from stimulus to response is:
What are sensory neuron → interneuron → motor neuron?