Portage Biod 152 module 1 exam

this is a collection of cell bodies found in the peripheral nervous system

ganglia

This part of the autonomic system accelerates the heart beat and increases breathing rate.

sympathetic nervous system

the dorsal root of a nerve contains what type of neurons?

sensory/ afferent

this part of a neuron conducts nerve impulses towards the cell body

dendrites

A neuron going to the bicep of the forearm is part of the:

central nervous system and autonomic nervous system

the neuron pictured below is best described as

bipolar

T/F: neurons do not physically touch one another

true

describe the function and release of neurotransmitters

-neurotransmitters are chemicals stored inside secretory vesicles (axon terminal vesicles) at the end of the axon terminals

-when neurotransmitters are released by the axon terminal vesicles, they carry the transmission of the nerve impulse from one neuron to another

an afferent neuron carries information:

From the peripheral to the central nervous system

a postsynaptic neuron would be found:

after the synapse

what is the location and function of satellite cells?

-PNS

-regulation of environment of neuron cell bodies

a patient's thumb was severed in a cooking accident and then reattached during surgery. would the patient be expected to regrow axons in their thumb? why or why not

yes; PNS nerves can regenerate the length of the axon through axonal regeneration because of the growth of Schwann cells ahead of the axon

name and describe what is occurring in the neuron cell membrane in section 2 of the diagram. include the charge of the membrane during this phase

-depolarization: the sodium gates open and sodium rushes into the axon during the depolarization phase of the action potential

-voltage travels past zero and then on up to +40mV

at rest, a neuron plasma membrane is:

Polarized (around -70mV)

which of the following is false concerning the sodium potassium pump

the overall effect is a negative charge on the outside of the membrane

T/F: a sensory neuron is signaling the body of a light touch. this means that the strength of the action potential is weaker than usual. explain your reasoning.

False. there is no variation in the strength of action potentials (it is an all or nothing response) there is variation in the number and frequency of neurons firing.

which of the following statements is true concerning the neuromuscular junction

The NMJ terminates on a muscle fiber

What prevents continuous stimulation of a nerve synapse and how is this accomplished?

the short existence of neurotransmitters in the synapse prevents continuous stimulation. some synapses contain enzymes that rapidly inactivate neurotransmitters and other synapses rapidly absorb the neurotransmitter

what neurotransmitter helps regulate emotional responses and muscle tone?

dopamine

T/F: action potentials travel in one direction within the same neuron

true

T/F: reflexes occur slower than a conscious decision to move from the brain

false

In a reflex, the ____________ neuron conducts nerve impulses along a pathway towards the central nervous system.

sensory/afferent

This part of a reflex is inside the CNS, made up of one or more synapses.

integration center

which of the following statements is false about reflexes?

pulling a hand away from a hot flame is not a reflex; it is entirely voluntary

what is false about the stretch reflex?

The effect of the motor signal is to relax a muscle.

what is true about the flexor withdrawal reflex?

It involves excitatory interneurons.

It involves inhibitory interneurons.

You touch a hot pan when cooking. List out the steps, in detail, of the nervous pathway of the reflex that occurs. Include any sensory organs involved and the action of the reflex.

flexor withdrawal reflex:

-pain receptor in skin

-sensory (afferent) neuron through DRG

-interneurons in spinal cord

a) exitatory to biceps

b) inhibitory to biceps

-motor neurons: contract biceps, inhibit triceps

-action: elbow flexion pulls hand away from flame

Botulism is a disease caused by a neurotoxin that interferes with the release of Acetylcholine. Patients with this disease experience flaccid paralysis, or the inability to contract their muscles. Explain why this would occur.

the nervous system interacts with the muscular system at the neuromuscular junction. acetylcholine must be released from the presynaptic motor neuron into the synapse to bind onto the muscle fiber, eventually causing a muscle contraction. without the release of acetylcholine, there will be no interaction between the nervous system and the muscular system and therefore no muscle contraction

This part of the autonomic system increases digestion.

parasympathetic

The neuron pictured, below, is best described as:

multipolar

describe the synthesis and storage of neurotransmitters

the neuron cell body manufactures neurotransmitters, which are stored in the secretory vesicles at the end of axon terminals

an efferent neuron carries information

From the central to the peripheral nervous system

a presynaptic neuron would be found

before the synapse

what is TRUE concerning the sodium potassium pump

it must remain in constant operation to maintain the resting state

which of the following statements is false concerning the neuromuscular junction?

sodium irons release from the presynaptic motor neuron

How is a message sent from one neuron to another?

There is a minute fluid-filled space, called a synapse, between the axon terminal of the sending neuron and the dendrite of the receiving neuron. When a nerve impulse reaches the end of an axon, neurotransmitters are released into the synapse. These bind with a receptor on the next neuron, opening Na+ gates in the receiving dendrite which causes depolarization and the impulse is carried.

Where is the integration center for the reflex arc always located?

CNS

which of the following statements is TRUE about reflexes?

regulation of blood sugar by hormones is one example of a reflex

Your doctor taps on your patellar tendon. List out the steps, in detail, of the nervous pathway of the reflex he is testing. Include any sensory organs involved and the action of the reflex.

stretch reflex:

-stretch on patellar tendon

-muscle spindle detects stretch

-afferent neuron through DRG

-spinal cord

-synapses directly on a motor neuron

-no interneuron

-action: to muscle fiber to connect quadriceps (kicking foot)

multiple sclerosis is autoimmune disease which attacks the myelin sheath of the nerve axon. patients with this disease may experience difficulty using the muscles of their arms and legs. explain why this would occur.

myelin increases nerve conduction speed and protects the nerve. if the myelin is damaged, the conduction speed is slower than normal, and the nerve axon itself is vulnerable to permanent damage without the myelin present for protection

the ventral root of a nerve contains what type of neurons?

motor (efferent)

name and describe what is happening in the neuron cell membrane in section 4 of the diagram. include the charge of the membrane during this phase:

-afterpolarization. potassium gates are slow to close and there is an undershoot of the potential

-the charge drops below -70 mV and then returns to that level once at resting state again

At rest, a neuron plasma membrane is:

-70mV (polarized)

how is a message sent from one neuron to another?

There is a minute fluid-filled space, called a synapse, between the axon terminal of the sending neuron and the dendrite of the receiving neuron. When a nerve impulse reaches the end of an axon, neurotransmitters are released into the synapse. These bind with a receptor on the next neuron, opening Na+ gates in the receiving dendrite which causes depolarization and the impulse is carried.

true or false: action potentials travel in one direction within the same neuron

true

true or false: reflexes occur only with conscious intervention from the brain

false

Fill in the blank: In a reflex, the ____________ neuron conducts nerve impulses along a pathway towards the central nervous system.

sensory (afferent)

what is true about the stretch reflex?

The muscle spindle detects stretch within the muscle.

what is false about the flexor withdrawal reflex?

It does not involve interneurons. The effect of the reflex is to create a co-contraction of two muscles

multiple sclerosis is an autoimmune disease which attacks the myelin sheath. patients with this disease may experience difficulty using the muscles of their arms and legs. explain why this would occur

myelin increases nerve conduction speed and protects the nerve. if the myelin is damaged, the conduction speed would be slower than normal, and the nerve axon itself would be vulnerable to permanent damage without the myelin sheath for protection

what is the location and function of astrocytes?

Location: Central nervous system (CNS)

Function: Regulation of chemical environment inside CNS, forming a physical barrier (blood-brain-barrier) by wrapping around blood capillaries

A patient's left thumb was severed in a cooking accident and then reattached during surgery. Would the patient be expected to regrow axons in their thumb? Why or why not?

yes; peripheral nerves can regenerate the length of the axon through axonal regeneration due to growth of Schwann cells ahead of the axon

name and describe what is happening in the neuron cell membrane in section two of the diagram. include the charge of the membrane during this phase

depolarization. the sodium gates open and sodium rushes into the axon during the depolarization phase of the action potential. voltage travels past zero and then on up to +40mV

what neurotransmitter is found at the neuromuscular junctions?

acetylcholine

This is a bundle of axons found in the peripheral nervous system.

nerve

This part of the autonomic nervous system increases heart rate and increases breathing rate

sympathetic

this part of a neuron conducts impulses away from the cell body

axon

An interneuron inside the spinal cord is part of the:

somatic system, central nervous system

you touch a hot pan while cooking. list out the steps, in order, in detail, of the nervous pathway of the reflex that occurs. include any sensory organs involved and the action of the reflex

flexor withdrawal reflex

-pain receptor in skin

-sensory neuron through DRG

-interneurons in spinal cord

-1: exitatory to biceps

-2- inhibatory to triceps

-motor neurons: contract biceps, inhibit tricseps

-action: elbow flexion pulls hand away from flame

The dorsal root of a nerve contains what type of neurons?

sensory/ afferent

this part of a neuron conducts nerve impulses away from the cell body

axons

An afferent neuron carries information:

From the peripheral to the central nervous system

A patient's spinal cord was severed in a car accident. Would the patient be expected to regrow axons in their spinal cord? Why or why not?

No; Only peripheral system axons are capable of regeneration. The spinal cord is in the central nervous system.

Name and describe what is occurring in the neuron cell membrane in section 4 of the diagram. Include the charge of the membrane during this phase.

Afterpolarization (Hyperpolarization) Potassium gates are slow to close and there is an undershoot of the potential.

The charge drops below -70mV and then returns to -70mV once at resting state again.

True or False: Action potentials travel in multiple directions within the same neuron.

false (only one direction in the same neuron)

Fill in the blank: In a reflex, the ____________ neuron conducts nerve impulses along a pathway to create a response.

sensory/ afferent

Where is the integration center of a reflex located?

CNS

What is false about the flexor withdrawal reflex?

A. It does not involve interneurons.

D. The effect of the reflex is to create a co-contraction of two muscles