InterActive Physiologyâ Exercise Sheets
Below is a table display showing you the eight modules and topics covered in the IP Exercise Sheets, which begin on the next page.
Module / Exercise TopicThe Muscular System / Neuromuscular Junction
Sliding Filament Theory
Contraction of Whole Muscle
The Nervous System / Ion Channels
Membrane Potential
The Action Potential
The Nervous System II / Ion Channels
Synaptic Transmission
Synaptic Potentials and Cellular Integration
The Cardiovascular System: The Heart / Intrinsic Conduction System and Cardiac Action Potential
Cardiac Cycle
Cardiac Output
The Cardiovascular System: Blood Vessels / Factors that Affect Blood Pressure
Blood Pressure Regulation
Autoregulation and Capillary Dynamics
The Respiratory System / Pulmonary Ventilation
Gas Exchange
Control of Respiration
The Urinary System / Glomerular Filtration
Early Filtrate Processing
Late Filtrate Processing
Fluid, Electrolyte, and Acid-Base Balance / Introduction to Body Fluids
Water Homeostasis
Acid-Base Homeostasis
The Endocrine System / Endocrine System Review
Biochemistry, Secretion and Transport of Hormones
The Actions of Hormones on Target Cells
The Hypothalamic-Pituitary Axis
Response to Stress
The Digestive System / Anatomy Review
Control of the Digestive System
Motility
Secretion
Digestion and Absorption
The Muscular System: Neuromuscular Junction
1. What insulates each muscle cell? ______
2. Synaptic vesicles in the axon terminal of a motor neuron contain what
neurotransmitter? ______
3. An action potential in the axon terminal of a motor neuron opens what type
of ion channels? ______
4. By what means of membrane transport does the neurotransmitter leave the
axon terminal? ______
5. Binding of neurotransmitter to the receptors on the motor endplate open
what type of ion channels? ______
6. Opening of these channels leads to ______of the motor endplate.
7. How is the neurotransmitter removed from the synaptic cleft?
8. As a result of question 6, an action potential is propagated along the
______of the muscle cell and down the ______
into the cell.
9. The result of this action potential releases what ion from the terminal
cisternae? ______
10. a. What effect did molecule “X” in the quiz have on the muscle contraction?
b. Explain its mechanism of action.
c. What drug did molecule “X” act like? ______
11. a. What effect did molecule “Y” have on the muscle contraction?
b. Explain its mechanism of action.
c. What drug did molecule “Y” act like? ______
12. a. What effect did molecule “Z” have on the muscle contraction?
b. Explain its mechanism of action.
c. What drug did molecule “Z” act like? ______
The Muscular System: Sliding Filament Theory
1. a. The thick filament is composed of what molecule?
______
b. Flexing the head of this molecule provides what is known as the
______.
2. The cross bridge (myosin head) contains binding sites for what two molecules?
a.
b.
3. Three molecules make up the thin filament.
a. Which molecule has a binding site for myosin cross bridges?
______
b. Which molecule covers this binding site?
______
c. Which molecule has a binding site for calcium ions?
______
4. What molecule must bind to the cross bridge in order for it to disconnect with
actin? ______
5. Hydrolysis of the molecule in question 4 returns the myosin molecule to the
______confirmation.
6. Binding of the cross bridges sequentially prevents ______
of the thin filament.
7. Name three roles for ATP in the contraction of muscle.
a.
b.
c.
8. What molecule is connected to the Z line? ______
9. Which of the following shorten during contraction? (may be more than one)
a. Thin filament
b. Sarcomere
c. H zone
d. Thick filament
10. a. What is the name of the condition in which muscles become rigid after
death? ______
b. What is this condition due to?
The Muscular System: Contraction of Whole Muscle
1. Which of the following contract in an all or none fashion?
a. Whole muscle b. Single muscle fiber
2. The development of tension in a muscle, in response to a stimulus above
threshold, is called a ______.
3. Identify the three phases of a muscle twitch from the following definitions:
a. Sarcomeres shorten ______
b. Sarcomeres return to resting length ______
c. Sarcomeres at resting length ______
4. a. Temporal summation results from:
b. In temporal summation, you must ______(or¯) the time interval between
stimuli.
5. Below is a list of the five phases of temporal summation. Put in the correct
order and describe each stage.
Order / Stage / DescriptionFatigue
Incomplete tetanus
Treppe
Complete tetanus
Temporal summation
6. In the Motor Unit Summation section, how many motor units were required to lift the weights when:
a. the weight was 160? ______
b. the weight was 80? ______
7. In the next lab simulation, what was:
a. the threshold stimulus? ______V
b. voltage when recruitment was obvious? ______V
c. voltage when all motor units were recruited? ______V
8. a. In the Length-Tension Relationship experiment, at what degree of stretch was
the maximum tension developed? ______
b. What would congestive heart failure be an example of?
______
The Nervous System: Ion Channels
1. What structures in the cell membrane function as ion channels?
2. Ion channels are selective for specific ions. What three characteristics of the ions are important for this selectivity?
a.
b.
c.
3. Channels can be classified as either active or passive channels. A sodium
channel that is always open would be classified as a/an ______channel.
4. Would sodium ions move into or out of the neuron through these channels?
______
5. Voltage-gated potassium channels open at what voltage? ______mV
6. Acetylcholine (ACh) and GABA are neurotransmitters that open chemically-gated channels. What ions pass into the cell when these channels are activated?
a. ACh: ______ions
b. GABA: ______ions
7. Ion channels are regionally located and functionally unique. List all the areas on the neuron and the type of potential dependent on the following types of ion channels:
Channels / Areas on the neuron / Type of potentialPassive
Chemically-gated
Voltage-gated
8. From the quiz, place an “X” by the characteristics of voltage-gated sodium channels.
______Always open
______Found along the axon
______Important for action potential
______Opened and closed by gates
______Found on the dendrites and cell bodies
______Important for resting membrane potential
9. Name two channels (active or passive) through which chloride ions could pass into the cell through.
a.
b.
10. a. The Japanese puffer fish contains a deadly toxin (tetrodotoxin). What type
of channels does this toxin block? ______
b. What potential would this toxin block? ______
c. What specifically would cause death? ______
The Nervous System: Membrane Potential
1. Record the intracellular and extracellular concentrations of the following ions (mM/L):
Intracellular / ExtracellularSodium (Na+)
Potassium (K+)
Chloride (Cl–)
2. Excitable cells, like neurons, are more permeable to ______than to ______.
3. How would the following alterations affect the membrane permeability to K+? Use arrows to indicate the change in permeability.
a. An increase in the number of passive K+ channels ______
b. Opening of voltage-gated K+ channels ______
c. Closing of voltage-gated K+ channels ______
4. a. What acts as a chemical force that pushes K+ out of the cell? ______
b. What force tends to pull K+ back into the cell? ______
5. When the two forces listed above are equal and opposite in a cell permeable
only to K+, this is called the ______potential for K+
which is ______mV.
6. In an excitable cell, also permeable to Na+ and Cl–, the gradients mentioned
in question 4 would both tend to move Na+ ______the cell.
7. Would the gradients in question 4 promote or oppose the movement of Cl– into the cell?
a.
b.
8. Since the neuron is permeable to Na+ as well as K+, the resting membrane
potential is not equal to the equilibrium potential for K+, instead it is
______mV.
9. What opposes the movement (leakage) of Na+ and K+ ions? ______
10. What will happen to the resting membrane potential of an excitable cell if: (Write pos or neg to indicate which way the membrane potential would change.)
a. extracellular fluid concentration of K+ ______
b. ¯ extracellular fluid concentration of K+ ______
c. extracellular fluid concentration of Na+ ______
d. ¯ number of passive Na+ channels ______
e. open voltage-gated K+ channels ______
f. open voltage-gated Na+ channels ______
The Nervous System: The Action Potential
1. a. The action potential changes the membrane potential from ______
mV (resting) to ______mV and back again to the resting membrane
potential.
b. This results from a change in membrane permeability first to ______
then to ______due to the opening of what type of ion channels?
______
2. a. Where is the density of voltage-gated Na+ channels the greatest?
______
b. What areas of the neuron generate signals that open these voltage-gated
channels? ______
c. Opening of these channels causes the membrane to
______(voltage change).
3. a. If the membrane reaches the trigger point, known as
______, what electrical potential will be generated?
______
b. During the depolarization phase, voltage-gated ______channels open
and ______enters the cell.
4. What are the two processes that stop the potential from rising above +30 mV?
a.
b.
5. a. The opening of voltage-gated K+ channels cause the membrane to
______.
b. Does K+ move into or out of the cell? ______
c. If the membrane potential becomes more negative than –70 mV, this is
called ______.
d. This potential is caused by what characteristic of K+ permeability?
______
6. a. After an action potential, the neuron cannot generate another action
potential because ______channels are inactive. This period is called the
______period.
b. During the ______period, the cell can generate
another action potential but only if the membrane is ______(more or
less) depolarized.
7. a. Conduction velocity along the axon is increased by what two characteristics?
1. ______
2. ______
b. Conduction along a myelinated axon is called
______conduction.
8. a. Name the disease whose symptoms include loss of vision and increasing
muscle weakness: ______(from the quiz section)
b. What does this disease destroy? ______
c. How does this stop an action potential?
The Nervous System II: Ion Channels
1. List four neurotransmitters that bind to ion channels, these neurotransmitters
are called ______-acting neurotransmitters.
a.
b.
c.
d.
2. a. The binding of ACh opens ion channels in the dendrites or cell body that
permits both ______and ______to move through them.
b. Which ion would move into the cell? ______out of the cell?
______
c. Which ion has the greatest electrochemical gradient? ______
d. The net movement of these two ions would do what to the cell?
______
e. This would be called an ______
postsynaptic potential, or ______.
3. a. An inhibitory postsynaptic potential (IPSP) causes a neuron to
______.
b. An example of a neurotransmitter that causes an IPSP is ______.
c. What type of ions move into the cell in response to this neurotransmitter?
______.
4. a. Norepinephrine binds to a receptor that is separate from the ion channel.
This is known as a/an ______- acting
neurotransmitter.
b. Norepinephrine is known as the ______messenger.
c. The receptor is coupled to the ion channel by a ______.
5. a. This activates an enzyme which induces the production of a
______messenger.
b. An intracellular enzyme is activated and ______the ion channel.
c. As a result of this sequence of events, what channels are closed?
______
d. What does this do to the neuron? ______
6. Name three neurotransmitters that can only act indirectly.
a.
b.
c.
7. Which of the four neurotransmitters mentioned in question 1 can also act indirectly?
a.
b.
c.
8. Which one of the four neurotransmitters mentioned in question 1 can
only act directly? ______
The Nervous System II: Synaptic Transmission
1. What channels in the presynaptic neuron open up in response to an action
potential? ______
2. The presence of what ion inside the cell causes the synaptic vesicles to
fuse with the membrane? ______
3. a. What is the name for the chemicals stored in the synaptic vesicles?
______
b. What do these chemicals diffuse across? ______
c. Where do these chemicals bind to receptors? ______
4. What type of gated channels do these chemicals open? ______
5. Name two ways these chemicals can be removed from the synaptic cleft.
a.
b.
6. The response on the postsynaptic cell depends on two factors:
a.
b.
7. Name the two types of cholinergic receptors and indicate where these are found.
excitatory:
inhibitory:
8. Indicate where the following three adrenergic receptors are found:
a1b1
b2
9. Autonomic nerves innervate what three things?
10. The most common excitatory neurotransmitter in the CNS is
______.
11. Two major inhibitory neurotransmitters in the CNS are:
a.
b.
12. Name a drug that alters synaptic transmission in the following ways:
a. blocks the action of the neurotransmitter at the postsynaptic membrane
______.
b. blocks the reuptake of the neurotransmitter at the presynaptic membrane
______.
c. blocks the release of the neurotransmitter ______and
______.
The Nervous System II: Synaptic Potentials and Cellular Integration
1. Enhanced postsynaptic potentials are due to increased ______entering the
terminal as a result of ______.
2. Presynaptic inhibition is due to decreased ______entering the terminal as
a result of ______.
3. a. Synaptic potentials are also known as ______potentials.
b. They ______as they travel away from the synapse.
4. a. Increasing the number of action potentials on an axon in a given period
of time would cause ______summation.
b. Increasing the number of synapses from different neurons would cause
______summation.
5. The magnitude of the EPSPs may be reduced (thus affecting their ability to
generate and their action potential) by adding ______
potentials, or ______s.
6. Inhibitory synapses would have the maximum effect if located where?
______
7. From the quiz, how many impulses did it take to cause an action potential: