Nervous System

The junction specialized for the transmission between a neuron and another cell is called a (1) _____ ______. Usually, the signal being sent to the receiving cell is carried by chemical messengers called (2) _____. (3) _____ is an example of this type of chemical messenger, which diffuses across the synaptic cleft, combines with protein receptor molecules on the muscle cell membrane, and soon thereafter is rapidly broken down by enzymes. At an (4) ____ synapse, the membrane potential is driven toward the threshold value and increases the likelihood that depolarization and an action potential will occur. At an (5) ____ synapse, the membrane potential is driven away form the threshold value, and the receiving neuron becomes hyperpolarized and is less likely to achieve an action  potential. A specific transmitter substance can have either excitatory or inhibitory effects depending on which type of protein channel it opens up in the (6) ____ membrane.
(7) ____ are neuromodulators that inhibit perceptions of pain and may have roles in memory and learning, emotional states, temperature regulation, and sexual behavior. (8) ____ ________ at the cellular level is the moment-by-moment tallying of all excitatory and inhibitory signals acting on a neuron. Incoming information is (9) ____ by the cell bodies, and the charge differences across the membranes are either enhanced or inhibited.
Some narrow-diameter neurons are wrapped in lipid-rich (10) _______ produced by specialized neuroglial called Schwann cells; each of these is separated from the next by a(n) (11) ________ ________ - a small gap where the axon is exposed to extracellular fluid.
A (12) ____ is an involuntary sequence of events elicited by a stimulus. During a (13) _______ ________, a muscle contracts involuntary  whenever conditions cause a stretch in length; many of these help you maintain an upright posture despite small shifts in balance.
Imbalances can occur at chemical synapses; a neurotoxin produced by Clostridium tetani blocks the release of GABA and glycine, thus freeing the motor neurons from (14) _____ control, which may cause tetanus - a prolonged, spastic paralysis that can lead to death.
A. excitatory
B. inhibitory
C. myelin
D. chemical synapse
E. synaptic integration
F. exposed node
G. reflex
H. stretch reflex
I. summed
J. neurotransmitters
K. postsynaptic
L. Endorphins
M. Acetylcholine (ACh)



Matching: Match the part of the brain to its described function.
1. ___ cerebellum A. monitors activities of internal organs; influences behaviors related to thirst, hunger, reproductive cycles, and temperature control.
2. __ corpus callosum B. coordinates muscles required for speech; houses many banks of fact memories.
3. __ hypothalamus C. receives inputs from cochleas of inner ears.
4. __ limbic system D. issues commands to muscles
5. ___ medulla oblongata E. relays and coordinates sensory signals to the cerebrum.
6. ___ occipital lobes F. receives inputs from receptors in nasal epithelium
7. ___ olfactory lobes G. receives and processes input form body-feeling areas.
8. ___ prefrontal cortex H. broad channel of white matter that keeps the two cerebral hemispheres communicating with each other.
9. ___ primary motor cortex I. coordinates nerve signals for maintaining balance, posture, and refined limb movements.
10. ___ primary somatic
             sensory cortex J. receives inputs from retinas of eyeballs.
11. __ temporal lobe K. connects pons and spinal cord; contains reflex centers involved in respiration, stomach secretion, and cardiovascular function.
12. ___thalamus L. contains brain centers that coordinate activities underlying emotional expression and memory.

Matching: Match the most appropriate category for each drug.
1. ___ amphetamines A. Depressant or hypnotic drug
2. ___ barbiturates B. Narcotic analgesic drug
3. ___ caffeine C. Psychedelic or hallucinogenic drug
4. ___ cocaine D. Stimulant
5. ___ ethyl alcohol
6. ___ heroine
7. ___ LSD
8. ___ marijuana
9. ___ nicotine