ch. 8 AS Test Study Guide

The basic mechanism for short-term sensitization begins with A)decreased neurotransmitter release. B)increased presynaptic calcium. C)increased expression of CREB-1. D)increased potassium conductance.

increased presynaptic calcium.

The simplest reflex arc, containing only a primary afferent and an effector neuron, is sometimes referred to as A)monosynaptic. B)bineural. C)convergent. D)voluntary.

monosynaptic.

The __________ nervous system is sometimes referred to as the "rest and digest" nervous system.

parasympathetic

Central pattern generators do NOT control A)rhythmic behaviors. B)motor pathways. C)reflex arcs. D)locomotion.

reflex arcs.

Among other things, the hindbrain is responsible for A)regulation of involuntary behaviors such as breathing. B)coordination of visual and auditory information. C)regulation of eating and reproduction. D)conversion of short-term memories into long-term memories.

regulation of involuntary behaviors such as breathing.

The three main regions of the vertebrate brain are the prosencephalon, the mesencephalon, and the __________.

rhombencephalon

All vertebrate motor neurons release the neurotransmitter __________.

acetylcholine

In the sympathetic and parasympathetic nervous systems, the preganglionic neuron releases the neurotransmitter A)acetylcholine. B)nicotine. C)glycine. D)epinephrine.

acetylcholine.

In vertebrates, substances from the blood can access the central nervous system by A)gap junctions. B)pinocytosis. C)catalyzed transport. D)all of the above

catalyzed transport.

Which of the following structures is NOT included in the limbic system? A)amygdala B)hypothalamus C)olfactory bulb D)cerebellum

cerebellum

The ventricles of the vertebrate brain contain A)neurons. B)glia. C)cerebrospinal fluid. D)dura mater.

cerebrospinal fluid.

Relative to other major groups of vertebrates, mammals and birds both have an enlarged A)forebrain. B)midbrain. C)hindbrain. D)dorsoventricular ridge.

forebrain.

The hippocampus is important for the A)formation of long-term memories. B)regulation of body temperature. C)Integration of sensory information. D)maintenance of body posture.

formation of long-term memories.

NMDA and AMPA receptors both bind the neurotransmitter __________.

glutamate

In species with cortical folds, the outer regions of the folds are called __________ and the inner grooves are called __________.

gyri; sulci

The tendency to reduce the magnitude of a response following repeated stimulation is called __________.

habituation

In a newly discovered vertebrate, the area in the somatosensory cortex devoted to body part A is larger than the area devoted to body part B. This means that body part A A)is bigger than body part B. B)has more sensory neurons. C)is evolutionarily older. D)has more motor control.

has more sensory neurons.

Which structure is important for the formation of long-term memory in mammals? A)hippocampus B)hypothalamus C)cortex D)medulla oblongata

hippocampus

Homeostasis is maintained by the A)hypothalamus. B)cerebral cortex. C)hippocampus. D)limbic system.

hypothalamus.

Split-brain syndrome follows from severing the __________.

corpus callosum

The mammalian cerebral hemispheres are connected by a mass of white matter called the __________.

corpus callosum

In vertebrates, the __________ nerves exit directly from the braincase.

cranial

How many distinct layers does the mammalian cortex have? A)6 B)4 C)3 D)2

6

If the central pattern generator for a human walking is located in the spinal cord, then is the brain required at all for successful walking behavior? Justify your answer.

A central pattern generator is a subset of neurons that can maintain spontaneous rhythmic output in the absence of sensory input. Therefore, the basic neural control for coordinating the action of the limbs during walking is housed in the spinal cord, and it can maintain its own activity without input from the brain. However, in a natural environment, inputs from the brain ARE required for a variety of other tasks associated with successful locomotion. For example, the cortex and brainstem are required to initiate locomotion. In other words, while the central pattern generator can maintain its own activity without input from the brain, it does, in fact, need a brain "trigger" in order to start. The cerebellum is required for balance and coordination to prevent the human from falling over. The brainstem controls the speed of locomotion. The cortex assists in regulating gait based on visual inputs such as obstacles and uneven terrain. Even though the central pattern generator can control basic muscular coordination, other sensory inputs and higher integrative inputs are required for successful walking behavior in a real setting

__________ is the evolutionary trend that describes the concentration of nervous tissue and sense organs at one end of the body.

Cephalization

Succinctly explain how ocean acidification can affect the behavior of fish, such as the orange clownfish (Amphiprion percula).

Clownfish live on coral reefs in close association with sea anemones. Clownfish larvae are strongly attracted to the scent of sea anemones and the scent of leaves of specific tropical rainforest trees, which are indicative of a suitable coral reef habitat. On the other hand, they show avoidance of leaves from specific tropical swamp trees, which indicate an undesirable swampy habitat. Acidified oceans can have a detrimental effect on the survival of clownfish larvae because their behavior changes: Larvae raised in acidified ocean water become very attracted to scents of swamp trees (unsuitable habitat) and their attraction for suitable coral reef habitats decreases. Another consequence of ocean acidification is the clownfish's attraction to the scent of predators instead of showing predator avoidance behavior. Research shows that ocean acidification causes this change in behavior of clownfish, and it is caused by a disruption in brain homeostasis. A decrease in extracellular Cl- interferes with chloride channels, more specifically the GABA-A receptor. The results of the research demonstrate that a small change in brain chemistry can affect behavior, and, as shown in the example of the orange clownfish, may lead to a decrease in survival of the species.

There is a large variation in brain size among vertebrates, and the relationship between brain size and brain complexity has always been a fascinating topic of study. What is meant by the term encephalization quotient (EQ)? What information does EQ provide, what are two problems with using EQs, and is there a better way to address the questions of brain complexity?

EQ is the ratio of the observed brain mass to the expected brain mass. When we compare EQ quotients, humans have the largest EQs, followed by some cetaceans such as dolphins, and then various species of primates. Social animals and carnivores have higher EQs than solitary and herbivorous animals. These findings suggest that EQs provide some information about cognitive capacity, and in general, behavioral complexity correlates well with EQ. Using EQs becomes problematic because the values obtained depends on the taxa used to obtain the regression line. The data used to generate the regression is also problematic because each point in the regression represents one entire species. As we know, there is much variation in body mass of different individuals in a species. To further complicate matters, even the mass of individuals can change dramatically over time, thus changing the EQ. Recent research by Dr. Herculano-Houzel uses a technique, which directly measures the number of neurons in the brain. The nuclei of brain cells are stained, which allows one to distinguish nuclei of neurons from non-neural glial cells. Dr. Herculano-Houzel's results comparing rodents and primates with similar-sized brains reveals that primate brains have more neurons per unit area, which may explain the higher cognitive capacity of primates. In addition, more neurons per unit area may also facilitate the formation of more synapses. Thus, counting neuron numbers holds some promise to potentially provide more knowledge about brain cognition and complexity.

Describe five differences between the actions of the parasympathetic and sympathetic nervous systems on the same effector organs. For example, the parasympathetic system causes urine release from the bladder, while the sympathetic system causes urine retention.

Effector organ Parasympathetic effect Sympathetic effect Pupil of eye Constricts Dilates Heart Slows heart rate Increases rate and force of contraction Arterioles None Constricts Digestive tract Increased motility and secretion Decreased motility and secretion Bladder Release of urine Retention of urine Sweat glands General sweating Localized sweating Bronchioles of lungs Constricts Dilates Adipose tissue None Fat breakdown

__________ neurons relay information from integrating centers such as the brain to effector organs like muscles or glands.

Efferent

List five ways that efferent motor pathways can be distinguished from autonomic pathways.

Efferent motor neurons control only one type of effector organ-skeletal muscle. Autonomic pathways control many organs. The cell bodies of motor neurons are located in the CNS, never in ganglia outside the CNS. Efferent motor pathways are monosynaptic, meaning that there is only a single synapse between the CNS and the skeletal muscle. This means that efferent motor neurons can be very long. Autonomic pathways are polysynaptic. Synapse morphology is different between autonomic and motor pathways. At the neuromuscular junction, a motor neuron splits into a cluster of axon terminals that branch out over the motor end plate. Autonomic neurons have several synaptic varicosities arranged in series like a string of beads. The size of the synaptic cleft is different. The synaptic cleft between the motor neuron and the muscle is much narrower than that between autonomic neurons and their effector cells. The nature of the neurotransmitter is different. All vertebrate motor neurons release acetylcholine at the neuromuscular junction, whereas sympathetic neurons release epinephrine and parasympathetic neurons release acetylcholine. The response of the effector organ differs. The effect of acetylcholine on skeletal muscle is always excitatory, whereas autonomic neurons may be excitatory or inhibitory.

Unlike humans, bottlenose dolphins do not suffer from the effects of sleep deprivation. Why? A) Dolphins "catnap" throughout the day, so they don't need to go into deep sleep. B) In dolphins, one half of their brain sleeps while the other half of the brain remains active. C) Sleep is required to maintain brain function in humans, but not in dolphins. D) Dolphins take turns waking each other up, so all have a chance to sleep.

In dolphins, one half of their brain sleeps while the other half of the brain remains active.

What does the midbrain do in fish and amphibians? A)It coordinates reflex responses to auditory and visual stimuli. B)It detects the presence of pheromones. C)It is responsible for maintaining body posture. D)It controls heart rate and blood pressure.

It coordinates reflex responses to auditory and visual stimuli.

Which of the following statements is true about learning? A)It refers to the retention and retrieval of stored information. B)It occurs only in vertebrates. C)It normally represents a permanent change. D)It occurs as the result of nervous system plasticity.

It occurs as the result of nervous system plasticity.

How can you explain the substantial lag between a signal and response in the phylum Porifera? A) Lag occurs because sponges are asymmetrical. B) Lag occurs because sponges show no cephalization. C) Lag occurs because action potentials in cells of sponges are slow compared to action potentials in neurons. D) Lag occurs because the signal has to be very strong in order to see any response.

Lag occurs because action potentials in cells of sponges are slow compared to action potentials in neurons.

This brain structure is greatly reduced in mammals relative to other vertebrates. A)cerebellum B)midbrain C)forebrain D)isocortex

Midbrain

What are the three main anatomical differences between the parasympathetic and sympathetic nervous systems?

Sympathetic Parasympathetic Originate in the thoracic and lumbar regions of the spinal cord Originate in the hindbrain or in the sacral region of the spinal cord Ganglia are found in a chain that runs close to the spinal cord Ganglia are located close to the effector organ Single preganglionic neuron synapses with 10 or more postganglionic neurons Preganglionic neuron synapses with three or fewer postganglionic neurons

In its protective role, the blood-brain barrier becomes an obstacle in delivering therapeutic drugs to specific regions of the brain in the treatment of a variety of brain disorders. Describe what the blood-brain barrier is made of, and how different compounds are capable of crossing it.

The blood brain barrier is formed by tight junctions between the endothelial cells lining the brain capillaries. It prevents materials from leaking out of the bloodstrea and into the central nervous system. These cells do not perform pinocytosis. Despite the tight junctions, there are still ways that compounds can cross the blood-brain barrier, including: 1. Dissolving in the membrane. Small lipid-soluble molecules such as ethanol and some barbiturate drugs can cross directly into the central nervous system. 2. Catalyzed transport mechanisms (protein exchanger, channel, pump) allow the brain to take up circulating nutrients such as glucose and amino acids. 3. In some areas of the brain, the blood-brain barrier is more permeable. In particular, the regions around the pineal gland, the pituitary gland, and parts of the hypothalamus are quite permeable, allowing secreted molecules such as hormones to leave the brain and enter the circulatory system.

What four major brain structures are included in the limbic system? Where is it located in the vertebrate brain? What does the limbic system do?

The limbic system is part of the forebrain, and lies on the border between the cortex and the rest of the brain. The four main structure included in the limbic system are (1) the amygdala, (2) the hippocampus, (3) the hypothalamus, and (4) the olfactory bulbs. The limbic system is often called the "emotional brain" because it controls emotions such as pleasure and fear, as well as decision-making, motivation, sex drive, hunger, and memory. The hypothalamus, within the limbic system, is also responsible for regulation of homeostasis, including body temperature, fluid balance, blood pressure, and body weight.

In the vertebrate spinal cord, the dorsal horn is associated with __________ neurons, and the ventral horn is associated with __________ neurons. A)motor; sensory B)inter; sensory C)afferent; efferent D)spinal; cranial

afferent; efferent

The limbic system is associated with A)emotion. B)motivation. C)decision-making. D)all of the above

all of the above

_____________ is a structure of the limbic system that is involved in emotional responses, such as fear or aggression.

amygdala

In the vertebrate brain and spinal cord, white matter consists of __________ and gray matter consists of __________. A)axons and myelin; cell bodies and dendrites B)sensory neurons; motor neurons C)axons and myelin; ganglia D)the dorsal horn; the ventral horn

axons and myelin; cell bodies and dendrites

The vertebrate central nervous system is physiologically separated from the rest of the nervous system by the __________.

blood-brain barrier

The brains of taxi drivers in London, England, differ from the brains of other people. This can be attributed to A) brain plasticity, because brains have the ability to alter their structure and function as a result of learning and/or experience. B) the hippocampus of London taxi drivers increasing with age. C) accident of birth; the people driving taxis in London were born with a smaller hippocampus, which then increased in size over time. D) A and B

brain plasticity, because brains have the ability to alter their structure and function as a result of learning and/or experience.

In mammals, the midbrain can be grouped together with the pons and medulla oblongata, and is called the __________.

brainstem

Integrating centers typically contain large numbers of A) interneurons. B)sensory neurons. C)efferent neurons. D)motor neurons.

interneurons.

The autonomic nervous system can be differentiated into three branches. Which of the following is NOT one of them? A)enteric B)sympathetic C)parasympathetic D)limbic

limbic

The hormone _______________ is secreted by the pineal gland.

melatonin

The protective layer of connective tissue surrounding the brain and spinal cord is called the __________.

meninges (or singular meninx)

In most vertebrates, except the mammals, the __________ contains the regions that are involved in interpreting visual information.

midbrain

In nonmammalian vertebrates, the optic lobes are located in the A)forebrain. B)midbrain. C)hindbrain. D)spinal cord.

midbrain.

The axons of afferent and efferent neurons are usually organized into structures called A)nuclei. B)ganglia. C)nerves. D)tracts.

nerves.

What receptors do the neurosecretory chromaffin cells of the adrenal medulla express? A)adrenergic B)muscarinic cholinergic C)nicotinic cholinergic D)glutamatergic

nicotinic cholinergic

In the mammalian brain, the __________ lobe is involved with visual processing. A)frontal B)parietal C)occipital D)temporal

occipital

An increase in a response following exposure to a strong or noxious stimulus is called __________.

sensitization

The only organ controlled by efferent motor neurons is __________.

skeletal muscle

Invertebrates possess a A)solid ventral nerve cord. B)hollow ventral nerve cord. C)solid dorsal nerve cord. D)hollow dorsal nerve cord.

solid ventral nerve cord.

The efferent branch of the peripheral nervous system is composed of the __________ and __________ divisions. A)somatic motor; autonomic B)visceral; emotional C)sympathetic; parasympathetic D)autonomic; involuntary

somatic motor; autonomic

The following structures of the mammalian nervous system, from posterior to anterior, are laid out in the following order: A)spinal cord, medulla oblongata, pons, cerebellum. B)spinal cord, pons, cerebellum, medulla oblongata. C)medulla oblongata, spinal cord, cerebellum, pons. D)pons, cerebellum, spinal cord, medulla oblongata.

spinal cord, medulla oblongata, pons, cerebellum.

The locomotor pattern generator is located in the A)spinal cord. B)brainstem. C)autonomic nervous system. D)peripheral nervous system.

spinal cord.

The __________ nervous system is sometimes referred to as the "fight or flight" nervous system. A)autonomic B)somatic C)parasympathetic D)sympathetic

sympathetic

Hearing a loud and unexpected noise in the night activates the A)sympathetic nervous system. B)parasympathetic nervous system. C)somatic nervous system. D)enteric nervous system.

sympathetic nervous system.

The __________ nervous system is most active during periods of stress or physical activity, while the __________ nervous system is most active during periods of rest. A)sympathetic; parasympathetic B)parasympathetic; sympathetic C)voluntary; involuntary D)parasympathetic; enteric

sympathetic; parasympathetic

The __________ is essentially a relay station that filters sensory information and forwards it to the cortex.

thalamus

Most sympathetic pathways originate in the __________ regions of the CNS. A)thoracic and lumbar B)hindbrain and sacral C)cranial D)postganglionic

thoracic and lumbar

The somatosensory cortex and primary motor cortex are organized __________. That is, each part of the cortex corresponds to the specific part of the body that it governs.

topographically