A&P 1 Lab Practical 2

The interior of the cell becomes less negative due to an influx of sodium ions.

Depolarization

The specific period during which potassium ions diffuse out of the neuron due to a change in membrane permeability.

Repolarization

Immediately after an action potential has peaked, which of the following channels will open?

Voltage-gated potassium channels

Which is by far the most common neuron type?

multipolar

Which neuron would be found in the retina of the eye?

Bipolar

At which stage is the Na+ channel open?

B (hyperpolarization)

Involved in activating fibers of a skeletal muscle such as the biceps muscle.

Diverging circuit

Maybe involved in complex, enacting types of mental processing

Parallel after-discharging circuit

some K+ channels remain open and Na+ channels reset

Hyperpolarization

In myelinated axons the voltage-regulated sodium channels are concentrated at the nodes of Ranvier.

True

At which stage is the voltage approaching +30mV?

B (hyperpolarization)

Which synapse will have the largest impact?

Axoaxonal

Which neurotransmitter is blocked by botulinum toxin?

Acetylcholine

At which stage are both sodium and potassium channels closing?

4 (D/Repolarization)

Which is channel is mechanically gated?

C

The term central nervous system refers to the ______.

Brain and spinal cord

Different types of sensory input can have the same ultimate effect.

Converging circuit

Which part of the image shows a chemically gated ion channel?

E

Which channel is B?

Chemically gated channel

One incoming axon triggers responses in ever-increasing numbers farther and farther along the circuit.

Diverging circuit

Put the typical serial processing of a reflex arc in order from the initial stimulus

1. Receptor detection

2. Sensory neuron firing

3. Interneuron signaling

4. Motor neuron signaling

5. Effector activated

Receives stimuli

Dendrites

Nerve impulses leading to the brain carry information about cool temperatures on the skin. The nerve fibers sending these signals will most likely belong to which division o the nervous system?

Sensory (afferent) divison

The specific period during which potassium ions diffuse out of the neuron due to a change in the membrane permeability

Repolarization

Which neuron is multipolar?

Which part of the image shows calcium ions?

B

Which part of the image shows a synaptic vesicles?

C

At which stage is the Na+/K+ pump working most to restore membrane potential?

D

Nerve impulses leading to the skeletal muscle carry information to direct movement. The nerve fibers sending these signals will most likely belong to which division of the nervous system?

Somatic nervous system

Which part of the image shows the action potential?

A

At which stage are both sodium and potassium channels closing?

D (repolarization)

Processes all input information

Cell body

Which channel is a?

Voltage gated channel

These cells in the CNS have cilia that move in order to circulate cerebrospinal fluid

Ependymal cells

Which part of the image shows calcium ions?

B

At which stage is the K+ channel open?

C (depolarization)

Voltage-gated Na+ channels open

depolarization

When a neurotransmitter like acetylcholine is acting in an excitatory manner which of the following is likely a result of the acetylcholine acting on the post synaptic cell?

Chemically gated sodium channels will open

Area where nerve impulse is generated.

Axon of hillock

Which part of the image shows the presynaptic membrane?

D

When a neurotransmitter like GABA is acting in an inhibitory manner which of the following is likely a result of the GABA acting on the postsynaptic cell?

Hyperpolarization of the postsynaptic cell membrane

The specific period during which potassium ions diffuse out of the neuron due to a change in membrane permeability

Repolarization

Which neuron is a sensory neuron found in a reflex arc?

unipolar (B)

What membrane is labeled b?

Endomysium

Which process requires ATP?

1. Sodium being removed from cytoplasm

2. Release Acetylcholine from synaptic vesicles

3. Myosin releasing form actin

4. Calcium storage in Sarcoplasmic Reticulum

5. Reloading myosin head into active position

What pairs up with troponin proteins to form a complex that blocks muscle contractions?

Tropomyosin

The ___ is a modified form of endoplasmic reticulum that stores and releases calcium ions when a muscle contracts

Sarcoplasmic reticulum

What part of a myofibril is E?

M Line

What part of a myofibril is C?

I Band

Describe what should have been observed after adding activating solution to muscle sample

Before adding the activating solution, the muscle sample was long and relaxed. After adding the activating solution, there was a lot of movement in a very short amount of time. It was noted that the muscle sample appeared to have shrunk, losing its length. It was very hard to see specifically what was happening, but after doing some research, there were a few things that happened that were too fast to catch. The first was that the I bands shortened, pulling the Z discs closer to the M line. The second was noticing that there was no longer a H zone - it completely disappeared. The last was realizing that the A bands had moved closer to each other, even though their length had not changed. That was due to the I bands shortening.

Define a sarcomere

The distance from one Z disc to the next z disc

At which stage of the contraction cycle will a muscle cell remain in after death?

myosin will be attached to actin and unable to release

Define I-Band in a sarcomere

Part of sarcomere with only actin

What part of the myofibril is B?

H Zone

___ are the proteins that appear as dark bands that mark the ends of the sarcomeres

Z lines

A rapid, very brief muscle contraction

muscle twitch

Muscle fibers designed for rapid and powerful responses

fast twitch muscle fibers

Calcium binds to this protein to initiate a contraction

Troponin

Protein that makes up the thin myofilament

Tropomyosin

Binds to troponin in the sarcomere to initiate muscle contraction

Calcium Ions

Covers the myosin-binding sites on actin

tropomyosin

Functions in the attachment of muscle to bone

tendons

Delivers the signals from the motor neuron to every sarcomere of the muscle cell

T tubules

Muscle fibers that are designed for endurance, contract slowly, and have a steady supply of energy

Slow twitch muscle fibers

Protein that makes up the thick myofilament

myosin

What structure is labeled D

Fascicle

Define the M line in a sarcomere

The center point where all myosin is bound together

What membrane is labeled A?

Epimysium

Propose what would happen to a sarcomere if ATP runs out, as in after death?

Each thick filament is composed of multiple myosin heads, which means that multiple cross-bridges form and break continuously during muscle contraction. Knowing this, it is extremely important for an abundance of ATP to be present in order to keep skeletal muscles healthy and working properly. Without ATP, it would be impossible for the myosin heads to detach from the actin-binding sites, which would leave the cross-bridges intact. This would mean that the muscles are fully contracted, leaving them stuck and stiff. This is known as rigor mortis - the muscles freeze and remain in the position that the person died in, making it extremely hard to reposition that person's body

Which of these structures is part of a muscle cell's plasma membrane that delivers signals to the sarcomere?

T tubule

Which of these junctions represents the connection between the tip of a neuron and a skeletal muscle cell from which acetylcholine diffuses?

neuromuscular

What part of the myofibril is D?

A band

Define the A band in a sarcomere

Part of a sarcomere that incudes myosin from one end to the other

What structure is labeled C?

muscle fiber

Define the Z disc in a sarcomere

the center point where all actin is bound together

What protein makes up the thin filament?

actin

A bundle of muscle cells is called a

fascicle

What part of the myofibril is A?

z- disc

What components are needed during a muscle contraction?

Troponin, Myosin, Sodium entering cell, Calcium, ATP, Actin, Acetylcholine

What membrane is labeled E?

Perimysium

During a muscle contraction which band should not be changed in size?

A band

What does calcium bind to in a sarcomere?

troponin

The arrangement of muscles so that the action of one muscle is the opposite to that of its partner is referred to as ____

antagonistic

What covers up the actin binding sites?

Tropomyosin

What protein pulls on tropomyosin to expose actin binding sites?

Troponin

During muscle contraction which band should be reduced in size?

I band

Which of the following are protein filaments that function in muscle contraction and are shaped like a golf club with two heads?

myosin filaments

Which process does NOT require ATP?

1. Opening of sodium gates on a muscle cell

2. Closing of sodium gates on muscle cell

Interneurons receiving input from sensory neurons are located in the ________.

dorsal (posterior) horn

Which area that encloses the central canal

A

Where are the white fiber tracts connecting the two hemispheres?

A

The corpora quadrigemina are found in the _____.

midbrain

What letter shows the hypothalamus?

C

The brain area just anterior to the precentral gyrus that selects and sequences basic motor movements into more complex tasks.

Premotor cortex

What type of cells line the ventricles of the brain?

ependymal cell

This area on the extreme posterior of the occipital lobe receives visual information that originates on the retina of the eye

primary visual cortex

The _____ includes the thalamus, hypothalamus and epithalamus

diencephalon

The brain area that regulates activities that control the state of wakefulness or alertness of the cerebral cortex is the _____

reticular formation

What structure is C?

Globus pallidus

Visual centers for the control of heart rate, respiration and blood pressure are located in the ______

medulla oblongata