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Anatomy 1 practice test

Terms in this set (60)

Z-line
The component of myofibrils that acts as an anchor for thin filaments is called the
Troponin
A 3 polypeptide subunit complex, this molecule is located in thin myofilaments
A-bands shorten
Which of the following is false regarding the contraction of the skeletal muscle?
ACh
During skeletal muscle fiber excitation, what is released from synaptic vesicles and travels across the synaptic cleft?
Cross-bridges form when myosin heads bind to actin
Cross-bridges are formed and broken repeatedly during contraction
Cross-bridges pull thin filaments toward the center of the sarcomere
Which of the following correctly describes the sliding filament model of contraction?
Voltage gated
What type of channel can open or close due to a change in membrane potential?
Depolarization of the sarcolemma
Which of the following occurs when acetylcholine binds to receptors in the junctional folds?
Influx of Na+
What causes an action potential to propagate along the sarcolemma?
End plate potential
The initial depolarization of the sarcolemma that occurs when the muscle fiber is stimulated by a motor neuron is called the
Just before contraction
When does excitation-contraction coupling end?
ADP and P are released
Actin filaments are pulled toward the M-line
During the power stroke of contraction,
Wave summation
When contraction becomes stronger due to stimuli arriving at the muscle fiber faster than complete relaxation can occur, it is known as
Voltage gated channels close
Ach is broken down
Ca++ is pumped back into the sarcoplasmic reticulum
During the relaxation period of skeletal muscle contraction
It inhibits contraction by blocking myosin binding sites on actin
What is the role of tropomyosin in skeletal muscles?
Isotonic and concentric
Which type of muscle contraction refers to when the muscle shortens?
Contraction
During what phase of a muscle twitch do myosin heads pull actin towards the center of a sarcomere?
Fused tetanus
Which graded muscles response is characterized by maximum tension with no Ca++ being pumped back into the sarcoplasmic reticulum?
Force of contraction would stay the same
What would happen if stimulus intensity exceeds the maximum stimulus?
Stored ATP
Creatine phosphate
ATP created by the electron transport chain
A person who runs a marathon uses which of the following sources of ATP?
Ca++ influx initiates an action potential in smooth muscle
Which of the following is a difference between smooth muscle and skeletal muscle?
Calveolae
The function of a t-tubule in skeletal muscle is similar to the function of what in smooth muscle?
Myasthenia gravis
The autoimmune disease that results in the destruction of acetylcholine receptors is called
Somatic nervous system
Which division of the nervous system conducts impulses from the central nervous system to skeletal muscle?
Somatic sensory fibers
Visceral sensory fibers
Which component of the sensory nervous system consists of mostly spinal nerves?
Ganglia
Clusters of cell bodies within the peripheral nervous system are called
Oligodendrocytes
The function of Schwann cells in the PNS is similar to the function of what in the CNS?
Uni-polar
The structural classification of neurons found mainly in the PNS is
Astrocytes
The function of satellite cells is similar to the function of
Telencephalon
The secondary brain vesicles that give rise to the cerebrum of the adult brain is
Basal nuclei, white matter, cerebral cortex
Which of following is the correct order of regions of the cerebral hemisphere from deep to superficial?
Frontal
The Broca's area is located in which lobe of the cerebral cortex?
Parietal
The primary somatosensory cortex is located in which lobe of the cerebral cortex?
Basal nuclei consist of gray matter
Basal nuclei are found only in the CNS
Basal nuclei influence muscle movements
Which of the following statements about basal nuclei is true?
The opening of voltage gated calcium channels
What causes synaptic vesicles to release acetylcholine from the axon terminals?
Hypothalamus
The pituitary gland secretes hormones that are regulated by the
Midbrain
What part of the brain is responsible for producing dopamine, a neurotransmitter?
Is a connective tissue covering of CNS
Consists of two layers around the brain
Is a superficial meninx
The dura mater
Send impulses from the brain to the spinal cord
Descending (efferent) tracts of the spinal cord
Ventral horns
The area of the spinal cord that consists of gray matter that contains mostly cell bodies that innervate skeletal muscle is
Pyramidal (corticospinal)
Which of the following pathways of efferent descending tracts do no synapse before reaching the spinal cord?
True
The somatic, autonomic, parasympathetic, and sympathetic nervous systems all transmit impulses from the central nervous system to the effectors.
True
Gaps in the myelin sheath that contain a high concentration of voltage gated ion channels are called nodes of Ranvier.
True
The central sulcus separates the frontal from the parietal lobe.
False
EPSPs are hyper polarization events and occur when chemically gated sodium channels are open.
False
Sodium ions cause synaptic vesicles in the axon terminals to expel acetylcholine into the synaptic cleft.
False
Muscular dystrophy is an autoimmune disease that destroys the myelin sheath, resulting in muscle weakness and paralysis.
True
The vital centers for the control of heart rate, respiration, and blood pressure are located in the medulla oblongata.
False
Graded potentials increase in amplitude as they move away from the stimulus point.
True
A motor neuron and all the muscle fibers that it innervates it referred to as a motor unit.
False
Commissural fibers are white matter tracts that connect the cerebral cortex to the lower brain areas.
ATP binding site
Myosin heads contain which of the following?
Sarcolemma and T-tubles
Which of the following contain voltage-sensative integral proteins?
T-tubles
Which of the following is not one of the three main components of the neuromuscular junction?
They stay the same length but move closer together
What happens to the Z-discs during contraction?
1
How many neuromuscular junctions does an individual skeletal muscle fiber have?
Voltage gated
Which channel type responds to changes in membrane potential?
Myosin heads binds to actin
Which of the following is not part of the process whereby a skeletal muscle fiber is stimulated by a motor neuron?
They can receive and respond to stimuli and their resting membrane potential can change
Muscle and nerve cells are excitable meaning __________.
Na+ influx into the intracellular fluid
In a skeletal muscle fiber, the depolarization phase of an action potential is due to _______________.
Two terminal cistern and a t-tuble
Which of the following are components of a triad?
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