NEUROTRANSMITTERS, RECEPTORS & INTEGRATION OF ELECTRICAL SIGNALS

Which of the following would occur if a person were given a drug that blocks the function of nicotinic receptors?

Skeletal muscle weakness/paralysis

The transmitter that is particularly associated with parasympathetic action, memory formation and skeletal muscle activation is:

acetylcholine

The last step in the activation of a reflex arc is the:

response of a muscle.

Which of the following effects would you expect from a drug which stimulates parasympathetic activity?

decreased heart rate

Testing a reflex can give information about:

• the sensory neuron involved in the reflex

• the motor neuron involved in the reflex

• the central nervous system

The Moro reflex is usually present until about:

4-5 months of age

The first step in the activation of a reflex arc is the:

activation of a sensory receptor

The last step in the activation of a reflex arc is the:

Response of a muscle

Accidentally touching the hot burner of a stove will elicit a(n) __________ reflex.

Withdrawal

The stretch reflex:

Is important in regulating posture

The simplest reflexes are organised at the level of the:

Spinal cord

Reflexes maintain homeostasis by making rapid adjustments in the functions of organs or organ systems. Each time a reflex is activated:

It produces the same response

Adrenergic beta-2 receptors are found on uterine smooth muscle in addition to blood vessels and bronchioles. Based on what you know about the actions that this receptor type produces, which of the following would be likely to occur when the beta-2 receptors on the uterus were stimulated?

Relaxation of uterine smooth muscle

A clinical use of activating beta-2 adrenoceptor would be for the treatment of:

Bronchial asthma

A drug which increased sympathetic activity would have which of the following effects on blood flow? 

Vasoconstriction in gut vessels resulting in decreased blood flow to the gastrointestinal tract

Blocking muscarinic receptors would reverse:

Bradycardia

Asthma can be treated by inhaling a drug that activates β receptors, however, if enough is inhaled it can enter the bloodstream. Which of the following effects would you expect it to occur if the drug entered the bloodstream?

Increased blood flow to skeletal muscles

Depression is associated with decreased levels of specific neurotransmitters. As such an effective treatment could involve:

• reducing the action of enzymes that breakdown the neurotransmitter

• addition of a drug that can cross the blood brain barrier and that mimics the neurotransmitter action at the receptor

• increase levels of the neurotransmitter at synapses by stopping the re-uptake of this neurotransmitter

Many antihistamines have sedating effects, which means they make people drowsy. There are now non-sedating versions of antihistamines. Which of the following would be likely to reduce or prevent the sedating effects?

Making the drug unable to cross the blood-brain barrier

Organophosphate pesticides are extremely toxic. The action of these chemicals is inhibition of acetylcholinesterase. Why would these compounds kill?

The inhibition of acetylcholinesterase leads to increased synaptic levels of acetylcholine. This leads to excessive stimulation of parasympathetic responses and skeletal muscles. The skeletal muscle transmission eventually fails, and death occurs due to respiratory paralysis.

Analgesia can be achieved by:

• disrupting signalling in the brain

• interfering with nociceptor signalling

• disrupting signalling in the spinal cord

The anti-asthma medication Salbutamol (Ventolin) works by activating noradrenaline receptors. Which of the following medications would you predict should be used with caution in asthmatics? 

Medications that block Beta receptors

The transmitter that is particularly associated with parasympathetic action, memory formation and skeletal muscle activation is:

Acetylcholine

Which of the following effects would you expect from a drug which stimulates parasympathetic activity?

Decreased heart rate

Which of the following is an important inhibitory neurotransmitter in the brain?

Gamma- aminobutyric acid (GABA)

Which of the following would occur if a person were given a drug that blocks the function of nicotinic receptors?

Skeletal muscle weakness/paralysis

Which set of responses would happen if the ß₁ receptors were activated?

Tachycardia & Increased blood pressure

During the withdrawal reflex

• both stimulation and inhibition of motor neurons occurs

• effector muscles cause removal from the source of pain

• the pain neuron synapses with three other neurons

Testing a reflex can give information about:

• the motor neuron involved in the reflex

• the central nervous system

• the sensory neuron involved in the reflex

Which of the following is true regarding the Babinski reflex?

A positive Babinski sign in an adult is a sign of damage to the corticospinal motor tract

If a neuron received an inhibitory neurotransmitter from a presynaptic cell at the same time it received an excitatory neurotransmitter from a second presynaptic cell the result wouild be

inhibition of action potentials in the neuron if the inhibitory neurotransmitter remained in the synapse longer

For a single drug to produce pupillary dilation, increased blood pressure, urinary retention and constipation, it would have to

Activate a1 receptors

Activating α receptors would be appropriate in the management of:

Nasal congestion

When administering an acetylcholinesterase inhibitor, the nurse should be aware of the possibility of a cholinergic crisis (overdose). What symptoms would you expect if this was to happen?

Increased salivation, abdominal cramps and diarrhoea, bronchoconstriction, skeletal muscle paralysis  

Which of the following represents the correct sequence for a simple spinal reflex arc?

receptor, afferent neuron, integration centre, efferent neuron, effector

Mrs Jones is a 50 year-old woman who is suffering from bradycardia and problems with her blood pressure, often fainting if she stands up quickly. To rectify this, she needs a drug that will act on the autonomic system to increase her heart rate, as such the drug would need to either

activate beta-1 receptors or block the action of muscarinic receptors