IB Biology
Activity
C2.2 Neural Signaling
Instructions
Read the questions carefully and provide the correct answers. Mind the command terms.
1. Describe that the nervous system consists of the central nervous system (CNS)
and peripheral nerves and is composed of cells called neurons that can carry
rapid electrical impulses.
The nervous system is made up of the central nervous system (CNS) and peripheral
nerves. The CNS includes the brain and spinal cord, while the peripheral nerves extend
throughout the body, connecting the CNS to various organs, muscles, and tissues. The
nervous system is composed of specialized cells called neurons, which are capable of
carrying fast electrical impulses. These impulses allow the nervous system to
communicate quickly and efficiently, coordinating bodily functions, responding to stimuli,
and regulating activities such as movement, sensation, and cognition.
2. Draw and label a diagram of the structure of a motor neuron.
, 3. State that nerve impulses are conducted from receptors to the CNS by sensory
neurons, within the CNS by relay neurons, and from the CNS to effectors by motor
neurons
Nerve impulses are conducted from receptors to the CNS by sensory neurons, within the
CNS by relay neurons and from the CNS to effectors by motor neurons.
4. Name three different roles of integral proteins in cell membranes.
Integral proteins in cell membranes have several important roles which include
transportation, cell recognition and adhesion as well as signal transduction.
5. How can integral proteins in a neuron plasma membrane cause an electrical
potential across the membrane?
Integral proteins in a neuron's membrane, like ion channels and pumps, help create
electrical potentials by regulating ion flow. Ion channels let ions such as sodium and
potassium pass in and out, altering the neuron's electrical charge. Sodium channels
opening lead to a quick influx of sodium ions, creating an action potential.
Sodium-potassium pumps maintain the charge difference by moving ions to keep the
neuron ready for signaling (Alberts et al., 2014; Kandel et al., 2000).
6. What do these proteins do to carry the nerve impulse along the neuron axon
To carry the nerve impulse long the neuron axon, proteins go through action potential
which is a process that begins with depolarization, meaning the sodium channels open,
the charge is at -70 and the nerve impulse is carried across the concentration gradient.
After depolarization comes repolarization which opens potassium K+ channels and
charges to 30 with the nerve impulse moving against the concentration gradient. And
finally there’s the refractory period where the charge goes to -80 and the sodium
potassium pump works to restore the original ion balance and thus ready the neuron
axon for a new impulse.
7. Na+ and K+ channels are not evenly spaced along a myelinated axon. Instead,
they are found in groups at places where the axon is not covered by myelin
sheath, called the nodes of Ranvier. In a myelinated axon the impulse travels
faster because the depolarization of the axon at one node leads to depolarization
at the next node by conduction within the axon. The depolarization “jumps” from
one node to another; which is called saltatory conduction. Explain how a nerve
impulse passes along a non-myelinated neuron
In comparison to travelling along a myelinated axon, nerve impulses that travel along a
non-myelinated neuron move at a much slower rate. This is due to the fact that since the
action potential is not clustered at nodes like in myelintaed axons, action potentials need
to occur in each point of the axon to continue along, rather than in a saltatory motion.
Activity
C2.2 Neural Signaling
Instructions
Read the questions carefully and provide the correct answers. Mind the command terms.
1. Describe that the nervous system consists of the central nervous system (CNS)
and peripheral nerves and is composed of cells called neurons that can carry
rapid electrical impulses.
The nervous system is made up of the central nervous system (CNS) and peripheral
nerves. The CNS includes the brain and spinal cord, while the peripheral nerves extend
throughout the body, connecting the CNS to various organs, muscles, and tissues. The
nervous system is composed of specialized cells called neurons, which are capable of
carrying fast electrical impulses. These impulses allow the nervous system to
communicate quickly and efficiently, coordinating bodily functions, responding to stimuli,
and regulating activities such as movement, sensation, and cognition.
2. Draw and label a diagram of the structure of a motor neuron.
, 3. State that nerve impulses are conducted from receptors to the CNS by sensory
neurons, within the CNS by relay neurons, and from the CNS to effectors by motor
neurons
Nerve impulses are conducted from receptors to the CNS by sensory neurons, within the
CNS by relay neurons and from the CNS to effectors by motor neurons.
4. Name three different roles of integral proteins in cell membranes.
Integral proteins in cell membranes have several important roles which include
transportation, cell recognition and adhesion as well as signal transduction.
5. How can integral proteins in a neuron plasma membrane cause an electrical
potential across the membrane?
Integral proteins in a neuron's membrane, like ion channels and pumps, help create
electrical potentials by regulating ion flow. Ion channels let ions such as sodium and
potassium pass in and out, altering the neuron's electrical charge. Sodium channels
opening lead to a quick influx of sodium ions, creating an action potential.
Sodium-potassium pumps maintain the charge difference by moving ions to keep the
neuron ready for signaling (Alberts et al., 2014; Kandel et al., 2000).
6. What do these proteins do to carry the nerve impulse along the neuron axon
To carry the nerve impulse long the neuron axon, proteins go through action potential
which is a process that begins with depolarization, meaning the sodium channels open,
the charge is at -70 and the nerve impulse is carried across the concentration gradient.
After depolarization comes repolarization which opens potassium K+ channels and
charges to 30 with the nerve impulse moving against the concentration gradient. And
finally there’s the refractory period where the charge goes to -80 and the sodium
potassium pump works to restore the original ion balance and thus ready the neuron
axon for a new impulse.
7. Na+ and K+ channels are not evenly spaced along a myelinated axon. Instead,
they are found in groups at places where the axon is not covered by myelin
sheath, called the nodes of Ranvier. In a myelinated axon the impulse travels
faster because the depolarization of the axon at one node leads to depolarization
at the next node by conduction within the axon. The depolarization “jumps” from
one node to another; which is called saltatory conduction. Explain how a nerve
impulse passes along a non-myelinated neuron
In comparison to travelling along a myelinated axon, nerve impulses that travel along a
non-myelinated neuron move at a much slower rate. This is due to the fact that since the
action potential is not clustered at nodes like in myelintaed axons, action potentials need
to occur in each point of the axon to continue along, rather than in a saltatory motion.
