Chapter 2 Flashcards
(77 cards)
what are neurons and what are the 2 different types
- specialized cells that carry messages throughout the nervous system
1. afferent (sensory) neurons: relay messages from sense organs, receptors to the brain or spinal cord
2. efferent (motor) neurons: signals from brain, spinal cord to glands, muscles; movement
what are interneurons
- thousands of times more numerous than sensory or motor neurons
- carry information
- transmits between neurons in brain and neurons in spinal cord
what are the 3 parts of a neuron
- cell body: contains the nucleus, carries out metabolic functions
- dendrites: branch-like extensions of neuron, receive signals from other neurons
- axon: slender, tail-like extension of neuron, transmits signals to dendrites or cell body of other neurons, transmits signals to muscles, glands, other parts of the body
what are glial cells
- hold neurons together
- remove waste products (dead neurons); handle metabolic tasks
- make myelin for cell transmission tasks (pain transmission)
what are synaptic clefts
- gaps between axon terminals
- fluid-filled
what is a synapse
- axon terminal of sending neuron communicates with receiving neuron across synaptic cleft
what is resting potential
- neuron is at rest (not firing)
- inside axon normally more negative than positive ions
- at rest, neuron carries negative electrical potential (charge) compared to fluid outside cell
what is action potential
- neuron is stimulated; positive ions flow into axon
- membrane potential changes to positive value
- sudden, brief reversal is called action potential
what is the all or none law
- neuron fires or does not
what is the myelin sheath
- white, fatty coating around some axons
- speed up conduction
- impulses up to 100 times faster along axons with myelin sheath
what is excitatory
- neuron fires
what is inhibitory
- neuron does not fire
what are receptor sites
- the ‘lock’
- sites on dendrite or cell body of neuron
- interacts with neurotransmitters
what is reuptake
- neurotransmitters are taken from synaptic cleft into the axon terminal
what is acetylcholine
- neurotransmitter
- excitatory or inhibitory effects
- excites skeletal muscle fibres
- inhibits heart muscle fibres
- excited neurons involved in learning new information
what are the 4 types of monoamines
- dopamine
- norepinephrine
- epinephrine
- seratonin
what is dopamine
- excitatory and inhibitory
- for learning, attention, movement, reinforcement
- ability to feel pleasure
what is norepinephrine
- eating habits
- alertness
- wakefulness
what is epinephrine (adrenalin)
- affects metabolism of glucose
what is seratonin
- inhibitory
- mood, sleep, impulsivity, aggression, appetite, depression, anxiety disorders
what are the 3 amino acids
- glutamate
- GABA (gamma-aminobutyric acid)
- endorphins
what are the 2 main parts of nervous system
central nervous system - brain - spinal cord peripheral nervous system - connects CNS to all other parts of body
what is the spinal cord
- extension of the brain
- links body with brain
- sensory information can reach brain
- brain can send messages to muscles, glands, body parts
what are the 3 parts of the brainstem
- medulla
- reticular formation (reticular activating system)
- pons