Chapter 5: Sensorimotor System Flashcards
Specialized body components, collectively called sensory receptor organs, are sensitive to energies (stimuli) of various sorts that come into contact with the body. The job of these organs is to convert environmental energy into ______________.
electrical signals
The concept of _____ _____ states that particular nerve cells are, at the outset, labeled for distinctive sensory experiences and that the sensory qualities of any particular sensory afferent are _______. For instance, activity in the touch receptor pathway can be perceived as touch only.
labeled lines
predetermined
The change in the membrane potential of the receptor cell when it is stimulated is called a(n) ______ _______, which in many ways is similar to an _____.
generator potential
EPSP
- ______ _____are sensitive to pressure and vibration.
- ______ ______ are sensitive to touch with high spatial resolution and are slow-adapting.
- ______ ______, which probably function using a specialized Na+ channel, are sensitive to texture and are fast-adapting.
- ______ ______are sensitive to stretch.
- _____ _____ _______are sensitive to heat, pain, and cold
Pacinian corpuscles Merkel’s discs Meissner’s corpuscles Ruffini’s endings Free nerve endings
Somatosensory receptors show progressively less and less response to a stimulus that continues unchanged for some period of time. This process is called adaptation and is characteristic of ______ receptors but not ______ receptors.
phasic
tonic
Sensory information enters the CNS through the brainstem or ______ _____ and then reaches the _______, where the information is shared with the ______ ______, which directs the thalamus to suppress some sensations. Primary sensory cortex swaps information with _________ sensory cortex.
spinal cord
thalamus
cerebral cortex
nonprimary
_______ _________cortex is also known as S1, and it maps the ________ side of the body
Primary somatosensory
opposite
In the well-known diagram of the “homunculus,” the __________ cortex is arranged as an orderly map of the body surface, and all parts of the body are not represented equally. The most sensitive parts of the body contain the ______ _______ of receptors and therefore account for larger amounts of the _______ _____ .
somatosensory
highest densities
sensory cortex
Peripheral afferents transmit pain information through axons that synapse in the _____ horns of the spinal cord. The axons cross at the level of the spinal cord, and pain information is transmitted to _______ nuclei before being processed by cingulate cortex
dorsal
thalamic
____-loop control mechanisms, such as those involved in throwing a ball, are preprogrammed and operate without feedback.
Open
_____-loop systems, such as those involved in driving a car, are subject to on-line error correction and operate with feedback.
Closed
Open-loop systems optimize _____ , whereas closed-loop systems optimize _______ .
speed
accuracy
Muscles that oppose one another across a joint are called __________. Muscles in the arm that exemplify this arrangement are the biceps and triceps muscles
antagonists
Muscles that act together (that is, pull in the same direction) are called ________.
synergists
Muscle fibers have a striped appearance due to the regular arrangement of thick filaments called ______ and thin filaments called _____.
myosin
actin
During muscle contraction, acetylcholine activity at the neuromuscular junction (NMJ) prompts an influx of ___ and ____ into muscle fibers. The ______ heads bind and change position, and the filaments slide past one another, shortening the muscle.
Na+
Ca2+
myosin
Proprioceptive information about the position and movement of muscles and limbs is derived from two major types of muscle receptors:______ ________ , which are sensitive to the stretching of muscles, and _____ ______ organs, which are sensitive to the contraction of muscles.
muscle spindles
Golgi tendon
- When a muscle is contracted under a strong load, _____ ______ ______ are excited.
- When a muscle is relaxed, ______ receptor type is excited.
- When a muscle is stretched under a strong load, ____ receptor types are excited.
Golgi tendon organs
neither
both
The ______ reflex is a good example of spinal control of reflexive movement
stretch
Complete the following statements about the sequence of events in the stretch reflex.
An environmental disturbance occurs, such as a weight added to the hand. Stretching of \_\_\_\_\_\_\_ occurs. \_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_send signal. \_\_\_\_\_\_\_\_\_\_ are excited by input from muscle spindle and fire \_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_ , causing muscle to contract.
muscle
Muscle spindles
Motoneurons
action potentials
Complete the following statements about the effects of lesions in nonprimary motor cortex.
In lesions of the \_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_, fine motor control is spared, but stance, gait, and coordination between the hands are impaired. In lesions of the \_\_\_\_\_\_\_\_, voluntary movement and speech are lost, although automatic and reflex movements are spared.
premotor cortex
SMA
Neurons in the ventral subregion of ______ ______ (the F5 region) are called mirror neurons. In monkeys, these neurons have been shown to be active in coordinating arm and hand movements. These neurons also seem to fire whenever the monkey is observing another animal who is performing such coordinated movement.
premotor cortex
The three major forebrain nuclei of the basal ganglia are
putamen,
caudate nucleus
globus pallidus.
Damage to the cerebellum commonly disrupts a person’s sense of _______, and people with such lesions show disturbances of gait, referred to as _______ .
balance
ataxia
People with Parkinson’s disease move slowly, exhibit resting tremors of the hands and feet, walk with a rigid gait, and lack facial expressiveness. The basic brain pathology involves a progressive loss of _______-containing neurons of the _______ _______ , which project particularly to the _______ _______ .
dopamine
substantia nigra
caudate nucleus
The first symptoms of Huntington’s disease are slight clumsiness and twitches, but the disease soon progresses to a syndrome involving involuntary jerking and writhing movements of the body. Intellectual disorders also become prominent. True Huntington’s disease is associated with destruction of the ______ _______ , especially the caudate. Inhibitory circuitry containing the neurotransmitter ______ is especially vulnerable.
basal ganglia
GABA
