Ch 43 - Exam 4 Flashcards
Nervous system (34 cards)
What is an action potential?
Rapid temporary change in membrane potential - signal that is transmitted by neurons, 3 phases
What is a synapse?
gaps between axon of one cell and dendrites of another where information is passed
What are the parts of a neuron?
Dendrites - collect chimical signals
Cell body - integrates incoming signals and generates outgoing electrical signal to axon
Axon - passes chemical signals to dendrites of another cell or to an effector cell
What are the different neurons in the nervous system?
Sensory neurons
Central nervous system
Interneurons
Peripheral nervous system
Motor neurons
What is a reflex?
Sensory info going to the brain which in turn signals back
What is meant by the term ‘membrane potential’? How do our cells ‘get one’?
When electrical potential exists across a plasma membrane, potential = difference, potential = -55mV (threshold) to activate AP
What is a resting potential?
Neurons are at rest, difference in charge across the membrane (0=dead)
What are K+ leak channels vs voltage-gated channels?
K+ leak channels allow K+ out of the cell without expending ATP,
Voltage GC responds to charges that are present (voltage), fully open or fully closed, very fast, inactive for a short amt of time after closed
What events must take place for an AP to be sent on at the axon hillock?
membrane reaches threshold at -55mV
What is depolarization?
positive change in membrane potential, Na+ comes into cell
What is repolarization?
negative change in membrane potential, K+ voltage gated channels open and send K+ out of cell
What is hyperpolarization?
K+ VGC slower to close, overshoots resting potential
What affects the transmission speed of an AP?
diameter of axon (bigger = faster), myelination, neurotoxins
Why do AP’s only go in one direction?
due to delay in gates resetting, refractory period
What is the refractory period and why does it occur?
period of resetting of gates, happens due to hyperpolarization
What are ‘all or none’ potentials vs graded potentials and why do they occur that way?
all or none means it will not happen until it hits a certain threshold, and will ALWAYS happen when threshold is reached
graded = not all or none
What are EPSPs?
Excitatory - closer to threshold potential (more positive)
What are IPSPs?
Inhibitory - farther away from threshold potential (more negative)
What are neurotransmitters and how do they work?
how neurons signal to each other regarding action potentials,
Which parts of the nervous system are under our control?
somatic nervous system, skeletal muscles
Which parts of the nervous system are NOT under our control?
autonomic nervous system, smooth and cardiad muscle, glands
What are the parts of the brain?
Cerebrum
Cerebellum
Diencephalon
Brain stem
Frontal lobe
Parietal lobe
Occipital lobe
Temporal lobe
Corpus callosum
What is the Corpus Callosum?
Neurons that connect the left and right hemispheres of the brain
What is the difference between the Cerebrum and the Cerebellum?
Cerebrum is the large squiggly part of brain, cerebellum is the more condensed piece by the brain stem
