Key Concepts in Neuroanatomy and Muscle Physiology

Myasthenia Gravis is a collection of muscle disorders that cause muscle fatigue and weakness. What is the major mechanism?

d. Autoimmune destruction of nicotinic acetylcholine receptors

Which of the following statements concerning the brainstem is incorrect?

b. The brainstems controls sociosexual behaviors conducive to mating

Damage to which spinal cord component will affect only motor activity?

Ventral root

Astrocytes

a. Take up excess K+ from the ECF

c. Induce formation of the blood-brain barrier

d. Physically support neurons

e. Are important in the repair of brain injuries in neural scar formation

Which of the following statements concerning cerebrospinal fluid is incorrect?

c. It comes in direct contact with the neuronal and glial cells

Which of the following meninges is the layer closest to the brain and spinal cord?

Pia mater

Which is NOT a characteristic of a sympathetic pathway?

c. Postganglionic neurons release acetylcholine.

The subcortical regions of the brain (deep within cerebrum) include all of the following except

e. Cerebellum

You have a patient who, following a stroke, can understand a sentence but would have trouble repeating it, may have

c. Aphasia in motor speech (Broca’s) area

What is the name of the neural bridge connecting the two cerebral hemispheres of the brain?

Corpus callosum

Parasympathetic nervous system

a. Has long preganglionic neurons that end on terminal ganglia, which lie within or neat effector organs

b. Releases a postganglionic neurotransmitter that binds to muscarinic receptors

c. Dominates in quiet, relaxed and fed situations

This receptor binds to acetylcholine released from both sympathetic and parasympathetic preganglionic neurons

Muscarinic

Which of the following is the final step of the events occurring at the neuromuscular junction after an action potential arrives at the axon terminal?

b. Acetylcholine binds with receptors on the muscle cell membrane, opening sodium channels

Which of the following statements concerning sensory receptors is correct?

a. Receptor adaptation results in decrease in receptor sensitivity and a decrease in action potential frequency

Which of the following statements regarding the precision of locating a somatic stimulus is false?

e. Convergence of afferent neurons onto common ascending pathways increases activity

Which best describes lateral inhibition in the somatic sensory system?

c. The precision of locating a stimulus is increased by inhibiting signaling along neighboring pathways

Which of the following changes occur within a sarcomere during muscle contraction?

b. Both the I band and H zone are reduced

According to the sliding filament mechanism of muscle contraction,

e. Thin filaments slide inward towards the A band’s center as a result of cross-bridge cycling

During a cross-bridge cycle in skeletal muscle,

a. Linkage between actin and the myosin cross bridge is broken at the end of the cross-bridge cycle as Mg2+ binds to the myosin cross bridge

b. Myosin cross bridge is energized due to myosin-ATPase activity hydrolyzing ATP

Motor unit refers to

A single motor neuron and all of the muscle fibers it innervates

Tetanus toxin inhibits acetylcholinesterase activity. What will a person suffering from tetanus toxin poisoning look like?

a. All of the muscles of the body might present a tense, fully contracted state

The ability of a muscle fiber action potential to cause an increase in cytosolic calcium concentration is dependent upon

b. The conduction of action potentials down T-tubules which are in direct contact with the terminal cisternae of the sarcoplasmic reticulum

 What would be the result if the administration of a drug takes up all the ATP in a cell?

a. All cross-bridges will remain tightly bound to actin

 When a muscle has been repeatedly contracting at a moderate intensity for an extended period of time (more than a few minutes), what is the primary source of ATP?

Oxidative phosphorylation

A patient who sustains a blow to the side of the head above the cheekbone cannot remember the words to a new song on the radio, no matter how many times he hears it. The head injury likely damaged his ________.

Medial temporal lobe

The inability to reach out and touch an object with control and accuracy may result from damage to the _______.

Cerebellum

Some viruses can hide from the immune system by retrograde transport from atonal terminals in the skin to the cell body of a neuron. Which of the following might be an effective preventative therapy?

e. A dynein inhibitor

 A patient has been experiencing difficulty with homeostatic regulation. An MRI scan reveals a brain tumor. Which brain region is the tumor likely in?

e. the Hypothalamus

When you have a negative experience, , your brain ties the emotion to the memory so that you avoid similar experiences in the future. If you were in a bike accident, and were afraid to get on a bike again, which brain structure functional group is active in guiding your fear?

b. Limbic system

Autonomic nerve fibers supplying cardiac and smooth muscle and exocrine glands originate at cell bodies found in the _______.

a. Lateral horn

Which is characteristic of the “fast pain” pathway?

d. Impulses carried along myelinated A-delta fibers

Which of the following statements regarding the determination of stimulus intensity is true?

d. The frequency of action potentials increases with increasing stimulus intensity

If an individual was lacking a key amino acid and so couldn’t make and release substance P, what would happen?

d. They would experience a lack of sensation in some pain pathways

A person struggling with a stressful exam question might experience difficulty focusing her eyes on the paper because

d. Activation of her sympathetic nerves causes dilation of her pupils

You are dissecting a cadaver. You are tracing an individual neuron as it ascends the spinal cord to the brain. You know that this neuron carries somatic sensory information from an afferent presynaptic neuron. Which of the following is true?

a. All somatic sensory information that reaches the cerebral cortex is first processes in the thalamus

The conversion of stimuli into neuron potentials (electrical signals)

a. Is called sensory transduction

b. Stems from generation of receptor potentials

d. Requires an adequate level of stimulus

 A deficiency of the neurotransmitter dopamine in the basal nuclei causes ________.

Parkinson's disease

The striated appearance of skeletal muscle is due to the

b. Regular orderly arrangement of the thick and thin filaments into A and I bands

Sympathetic stimulation ___ heart rate and _____ the motility in the digestive tract

e. Increases, decreases

What is the fate of acetylcholine (ACh) following binding to receptors?

c. It is removed by the enzyme acetylcholinesterase

Which protein contributes to the elasticity of the sarcomere?

e. Titin

Which of the following characteristics are shared by all three types of muscle tissues?

e. each one contains Myosin and Actin

Which of these occurs during an isometric contraction of a skeletal muscle?

c. Sarcomere length does not change

How is the length of a skeletal muscle cell related to the force it can generate?

c. Skeletal muscle cells generate the most force when the contraction occurs at an intermediate length

Compared to type 1 (slow oxidative) skeletal muscle fibers, how are llb (fast-glycolytic) skeletal muscle fibers different?

c. Type llb fibers fatigue more readily

Of the steps in excitation-contraction below, which occurs before the others?

a. Sodium channels open in the sarcolemma

If you wanted to pick up something heavier than your pencil (such as your book), you need to have a stronger muscle contraction. In what way might you accomplish this?

c. Stimulate motor units

The regulation of smooth muscle contraction is mediated by the phosphorylation of

_____ in response to calcium binding to _____.

d. Myosin, calmodulin

In a reflex arc, what is the receptor?

d. The dendrite of an afferent neuron receiving the stimulus

Which of the following statements correctly describes white matter and gray matter?

e. White matter in the brain and spinal cord consist of myelinated axons, and gray matter in the brain and spinal cord consist of dendrites and cell bodies

Myasthenia Gravis is a collection of muscle disorders that cause muscle fatigue and weakness. What is the major mechanism?

d. Autoimmune destruction of nicotinic acetylcholine receptors

Damage to which spinal cord component will affect only motor activity?

Ventral Root

Which of the following meninges is the layer closest to the brain and spinal cord?

Pia Mater

Which is NOT a characteristic of a sympathetic pathway?

Postganglionic neurons release acetylcholine.

The subcortical regions of the brain (deep within cerebrum) include all of the following except

Cerebellum

You have a patient who, following a stroke, can understand a sentence but would have trouble repeating it, may have

c. Aphasia in motor speech (Broca’s) area

The Parasympathetic Nervous System

a. Has long preganglionic neurons that end on terminal ganglia, which lie within or near effector organs

b. Releases a postganglionic neurotransmitter that binds to muscarinic receptors

 c. Dominates in quiet, relaxed and fed situations 

This receptor binds to acetylcholine released from both sympathetic and parasympathetic preganglionic neurons

Nicotinic

Which of the following is the final step of the events occurring at the neuromuscular junction after an action potential arrives at the axon terminal?

b. Acetylcholine binds with receptors on the muscle cell membrane, opening sodium channels

Which of the following statements concerning sensory receptors is correct?

a. Receptor adaptation results in decrease in receptor sensitivity and a decrease in action potential frequency

Which of the following statements regarding the precision of locating a somatic stimulus is false?

e. Convergence of afferent neurons onto common ascending pathways increases activity

Which best describes lateral inhibition in the somatic sensory system?

c. The precision of locating a stimulus is increased by inhibiting signaling along neighboring pathways

Which of the following changes occur within a sarcomere during muscle contraction?

b. Both the I band and H zone are reduced

According to the sliding filament mechanism of muscle contraction,

e. Thin filaments slide inward towards the A band’s center as a result of cross-bridge cycling

During a cross-bridge cycle in skeletal muscle,

a. Myosin cross bridge is energized due to myosin-ATPase activity hydrolyzing ATP

b. Myosin cross bridge is able to bind with actin when Ca2+ removed trope in-tropomyosin complex from blocking position

Which of the following statements concerning the brainstem is incorrect?

The brainstems controls sociosexual behaviors conducive to mating

A Motor unit refers to

Single motor neuron and all of the muscle fibers it innervates

Tetanus toxin inhibits acetylcholinesterase activity. What will a person suffering from tetanus toxin poisoning look like?

a. All of the muscles of the body might present a tense, fully contracted state

The ability of a muscle fiber action potential to cause an increase in cytosolic calcium concentration is dependent upon

b. The conduction of action potentials down T-tubules which are in direct contact with the terminal cisternae of the sarcoplasmic reticulum

What would be the result if the administration of a drug takes up all the ATP in a cell?

a. All cross-bridges will remain tightly bound to actin

A patient who sustains a blow to the side of the head above the cheekbone cannot remember the words to a new song on the radio, no matter how many times he hears it. The head injury likely damaged his ________.

Medial temporal lobe

The inability to reach out and touch an object with control and accuracy may result from damage to the _______.

Cerebellum

May prevent viral retrograde transport in neurons.

b. A Dynein inhibitor

A patient has been experiencing difficulty with homeostatic regulation. An MRI scan reveals a brain tumor. Which brain region is the tumor likely in?

e. the Hypothalamus

When you have a negative experience, your brain ties the emotion to the memory so that you avoid similar experiences in the future. If you were in a bike accident, and were  afraid to get on a bike again, which brain structure functional group is active in guiding your fear?

Limbic system

Autonomic nerve fibers supplying cardiac and smooth muscle and exocrine glands originate at cell bodies found in the _______.

a. Lateral horn

Which is characteristic of the “fast pain” pathway?

d. Impulses carried along myelinated A-delta fibers

Astrocytes

a. Take up excess K+ from the ECF

c. Induce formation of the blood-brain barrier

d. Physically support neurons

e. Are important in the repair of brain injuries in neural scar formation

Which of the following statements regarding the determination of stimulus intensity is true?

d. The frequency of action potentials increases with increasing stimulus intensity

If an individual was lacking a key amino acid and so couldn’t make and release substance P, what would happen?

d. They would experience a lack of sensation in some pain pathways

A person struggling with a stressful exam question might experience difficulty focusing her eyes on the paper because

d. Activation of her sympathetic nerves causes dilation of her pupils

You are dissecting a cadaver. You are tracing an individual neuron as it ascends the spinal cord to the brain. You know that this neuron carries somatic sensory information from an afferent presynaptic neuron. Which of the following is true?

a. All somatic sensory information that reaches the cerebral cortex is first processes in the thalamus

The conversion of stimuli into neuron potentials (electrical signals)

a. Is called sensory transduction

b. Stems from generation of receptor potentials

d. Requires an adequate level of stimulus

A deficiency of the neurotransmitter dopamine in the basal nuclei causes ________. 

d. Parkinson's disease

Sympathetic stimulation ___ heart rate and _____ the motility in the digestive tract

e. Increases, decreases

What is the fate of acetylcholine (ACh) following binding to receptors?

c. It is removed by the enzyme acetylcholinesterase

The striated appearance of skeletal muscle is due to the

b. Regular orderly arrangement of the thick and thin filaments into A and I bands

Which protein contributes to the elasticity of the sarcomere?

Titin

Which of the following characteristics are shared by all three types of muscle tissues?

e. Each one contains myosin and actin

Which of these occurs during an isometric contraction of a skeletal muscle?

c. Sarcomere length does not change

 How is the length of a skeletal muscle cell related to the force it can generate?

C. Skeletal muscle cells generate the most force when the contraction occurs at an intermediate length

Compared to type 1 (slow oxidative) skeletal muscle fibers, how are llb (fast-glycolytic) skeletal muscle fibers different?

c. Type llb fibers fatigue more readily

Of the steps in excitation-contraction below, which occurs before the others?

a. Sodium channels open in the sarcolemma

If you would wanted to pick up something heavier than your pencil (such as your book), you need to have a stronger muscle contraction. In what way might you accomplish this?

C. Stimulate motor units

The regulation of smooth muscle contraction is mediated by the phosphorylation of _____ in response to calcium binding to _____.

d. Myosin, calmodulin

In a reflex arc, what is the receptor?

d. The dendrite of an afferent neuron receiving the stimulus

Which of the following statements correctly describes white matter and gray matter?

e. White matter in the brain and spinal cord consist of myelinated axons, and gray matter in the brain and spinal cord consist of dendrites and cell bodies

Which of the following statements concerning cerebrospinal fluid is incorrect?

c. It comes in direct contact with the neuronal and glial cells (It has the same composition as blood plasma)

Which glial cells affect the conduction velocity of CNS neurons?

e. Oligodendrocytes

Drugs that do this would decrease sympathetic function

E. Blocks the release of NE (norepinephrine)