BIOL 220 Exam 2 Homework - Connect
Encoding stimulus strength depends on which of the following? Check all that apply.
- Different neurons have different thresholds of excitation. - The more strongly a neuron is stimulated, the more frequently it fires.
What are the three general classes of neurons that correspond to the three major aspects of nervous system function? Check all that apply.
- Motor neurons that send signals predominantly to muscle and gland cells. - Interneurons that lie between, and interconnect the incoming sensory pathways and the outgoing motor pathways of the CNS. - Sensory neurons that are specialized to detect stimuli such as light, heat, pressure, and chemicals, and transmit information about them to the CNS.
Which of the following is/are true regarding muscular strength and conditioning? Check all that apply.
-Blood capillary density will increase in slow -Weight lifting does not increase the number of muscle fibers in a particular muscle exercised. -Long-term resistance training will increase the number of myofibrils in a particular muscle exercised.
Why is myelin important? Check all that apply.
-It speeds up signal conduction in the nerve fiber. -It is formed to assist in the regeneration of damaged fibers. -It insulates the nerve fiber.
Which of the following is/are a characteristic of skeletal muscle? Check all that apply.
-Overlapping thin and thick filaments -Striations -Overlapping myosin and actin proteins -Excitability
Which of the following is/are a component of all spinal reflex arcs? Check all that apply.
-receptor -afferent neuron -integrating center -efferent neuron
Place the following descriptions into the correct order to represent the sequence of events in a patellar reflex arc.
1.a tap on the pataller ligamennt excites nerve endings of muscle spindles in the quadriceps femoris 2.stretch signals travel to the spinal cord via a primary afferent neuron 3.a primary afferent nerve fibre stimulates an alpha motor neuron in the spinal cord 4.efferent signals in the motor nerve fibre stimulates the quadriceps to contract 5.a branch of afferent nerve fibre stimulates an inhibitory motor neuron in the spinal cord 6.The alpha motor neuron to the hamstrings muscle is inhibited 7.flexor muscles of the hamstrings relax to prevent antagonizing the quadricpes muscle
Which of the following describes twitch summation?
A second stimulus arrives at the muscle before complete relaxation of the first contraction, causing the second contraction to have greater tension than the first one.
Place each of the following labels in the proper position on the curve where each of the indicated items would occur
A: Na+ arrive at the axon hillock and depolarize the membrane at that point B: At threshold, voltage-gated Na+ channels open quickly C: Voltage-regulated K+ channels open D: Hyperpolarization E: Resting membrane potential
The bond between the active site on actin and the myosin head is broken when an __________.
ATP molecule binds to the myosin head
Place the following labels in the proper position to designate action potential or local potential
Action potentials - voltage-regulated sodium channels - voltage-regulated potassium channels - rate of transmission is increased with myelination - import for transmission over long distances - require threshold Local potentials - ligand-regulated sodium channels - cause summation - decremental - reversible Both - sodium-potassium ATPase pumps work to re-establish RMP
Which of the following is a true statement about the brain barrier system? Check all that apply.
Both brain barriers utilize tight junctions to keep harmful substance from getting to the tissue fluid of the brain. Alcohol, caffeine, nicotine, and anesthetics can all cross the brain barrier system. The brain barrier system is susceptible to trauma and damage. The brain barrier system is necessary because brain tissue is irreplaceable and therefore must be well protected
Which of the following structures consists mainly of white matter?
Corpus callosum
The cerebral aqueduct passes CSF down the core of the midbrain and into which of the following?
Fourth ventricle
click and drag the labels into the appropriate box to identify whether or not it is a possible function of the connective tissue component of a muscle based on some of the current theories.
Function of connective tissue -aids in elastic recoil of muscle -prevents the muscle from overstretching -helps the muscle function more efficiently -surrounds the muscle fascicle, binding them together Not a function of connective tissue -carries the electrical impulse for a muscle cell -striations allow for muscle contraction -contracts the muscle, making it shorter -stores glucose to provide energy to muscle cell
Exercise training induces beneficial adaptions according to the systems and structures that are stressed during activity. Please indicate how the following items would be altered following a lengthy training program.
Increase with anaerobic resistance training (glycolytic and phosphagen) -myofibril size and number -muscle size -lactic acid processing Increase with aerobic exercise training (glycolytic and phosphagen) -mitochondrial density -long-term fatigue resistance -muscular density of blood capillaries -blood volume and red blood cell count
What type of contraction is represented by each of the following events?
Isotonic Eccentric concentration -a sprinter leaves the starting block -a mother lowers an infant into his crib -a weight lifter puts a barbell back on the floor Isotonic Concentric contraction -a weight lifter pulls a barbell up to his waist -a man pulls open a door for his date
Match each event to the appropriate phase of a muscle twitch.
Latent period -immediately follows stimulation of the muscle -internal but not external tension generated -excitation-conctraction coupling -depolarization occurs in the T tubule Contaction phase -internal and external tension generated -sarcomeres shorten -power-stroke occurs -myofilaments slide over one another Relaxation phase -Ca2+ transported back into the sarcoplasmic reticulum -muscle tension decreases
Acetylcholine has which effect on the postsynaptic neuron?
Ligand gated sodium ion channels open and sodium diffuses in.
Why does depolarization occur?
More Na+ diffuse into the cell than K+ diffuse out of it.
Click and drag each event into the appropriate category based on whether it would be associated with a contraction or no contraction.
No concentration -active transport of Ca^2+ into the sarcoplasmic reticulum -a mutation to troponin that prevents it from binding Ca^2+ -a mutation to tropomyosin that prevents it from binding to troponin -an inhibitor of voltage-gated Na+ channels Contraction -release of acetylcholine -a mutation to tropomyosin that prevents it from binding actin -presence of an organophosphate pesticide that inhibits acetylcholinesterase -opening of calcium ion channels in the terminal cisterns -exposure of the active sites on the actin filament
Identify the energy system that would be most important for each of the following activities.
Phosphagen system -swatting at a mosquito -jumping on the bed -pitching a baseball -swinging a golf club -during a soccer game, jumping up to head a ball Glycogen-lactic acid system -running up a coupe flights of stairs -running the 400-meter dash -performing 25 push-ups -during a 10K run, sprinting up a 200-meter-long hill Aerobic Respiration supported by cardiopulmonary function -walking across campus -sitting upright at your desk writing a report -standing while giving a classroom presentation -marathon running -jogging on the beach
Why does repolarization occur?
Potassium ions continue to diffuse out of the cell after the inactivation gates of the voltage-gated sodium ion channels begin to close.
What happens as a result of ion flow at a presynaptic terminal?
Synaptic vesicles migrate to the plasma membrane and release acetylcholine.
Why does hyperpolarization occur?
The increased potassium ion permeability lasts slightly longer than the time required to bring the membrane potential back to its resting level.
Which structure do the calcium ions bind to when muscle contraction is initiated?
The troponin molecule
The resting membrane potential is negative due to which of the following?
There are more negatively charged particles on the inside of the membrane than on the outside.
Match each protein with the appropriate filament
Thick filaments -Myosin -myosin heads Thin filaments -actin -tropomyosin -troponin -active sites Neither thick nor thin filaments -dystrophin -elastic filament
Classify the following structures with the region of the spinal cord in which they are located.
Thoracic region -lumbosacral enlargement Cervical region -Cervical enlagrement Sacral and Lumbar region -medullary cone -cauda equina -terminal filum
During contraction of a muscle, calcium ions bind to the __________.
Troponin molecule
Spatial perception and the recognition of familiar objects require activity in which of the following cortical regions?
Visual association areas
An action potential arriving at the presynaptic terminal causes what to occur?
Voltage-gated calcium ion channels open, and calcium ions diffuse into the cell.
Cross-bridges form between the __________ and the __________.
actin filaments; myosin head
Assign each example to the universal muscle characteristic being described.
excitability -placing muscle in a solution containing calcium & ATP conductivity -action potentials in the center of the fiber radiating to the ends -depolarization of a single muscle fiber causing depolarization of adjacent muscle fibers contractility -creation of force -pulling two bones closer together -actively resisting the separation of two bones elasticity -a stretched muscle returning to it original length -passively resisting the separation of two bones extensibility -stretching a muscle -increasing sarcomere length
Which portion of a reflex arc is located entirely within the central nervous system?
interneuron
An action potential enters the depths of a muscle fiber by way of __________.
the T tubules
