Advanced Human Bioscience HUBS1416 week 3

Questions and Answers

Which neurotransmitter class is primarily involved in the autonomic sympathetic response?

Dopamine

Serotonin

Noradrenaline (correct)

Acetylcholine

Which of the following neurotransmitter manipulations is NOT typically used in the treatment of depression?

Selective Noradrenaline reuptake inhibitors (SNRIs)

Monoamine oxidase inhibitors (MAOIs)

Dopamine agonists (correct)

Selective serotonin reuptake inhibitors (SSRIs)

How are neurotransmitter effects generally terminated at the synapse?

Enzymatic breakdown only

Re-uptake into presynaptic neurons only

Diffusion away from the synapse

Re-uptake and enzymatic breakdown (correct)

What is a potential side effect of selectively targeting neurotransmitters in medication?

Side effects affecting different body systems Signup and view all the answers

Which treatment for depression works by blocking the re-uptake of serotonin?

Selective serotonin reuptake inhibitors (SSRIs) Signup and view all the answers

Which condition is NOT commonly associated with inappropriate levels of neurotransmitters?

Arthritis Signup and view all the answers

What physiological response does the sympathetic division primarily promote?

Fight or flight Signup and view all the answers

Which type of receptor produces a parasympathetic response?

Muscarinic receptors Signup and view all the answers

Which neurotransmitter is primarily associated with the somatic nervous system at the muscle level?

Acetylcholine Signup and view all the answers

Which of the following pairs includes neurotransmitters related to the central nervous system (CNS)?

All of the above Signup and view all the answers

How do endogenous opioids function during extreme stress?

They dampen pain signals Signup and view all the answers

Which of the following best describes the role of nociceptors?

They detect pain sensations Signup and view all the answers

What is a primary effect of β3 adrenoceptors?

Mobilizing fat Signup and view all the answers

What effect can improving depression have on physical health?

Enhanced digestive efficiency Signup and view all the answers

Which of the following neurotransmitters is associated with cholinergic receptors?

Acetylcholine Signup and view all the answers

What is the primary role of non-steroidal anti-inflammatories?

Reduce inflammation and pain Signup and view all the answers

Which statement describes a characteristic of reflexes?

They involve both peripheral and central nervous systems. Signup and view all the answers

At what age is the Moro reflex typically inhibited?

Around 4 months of age Signup and view all the answers

Which reflex is generally inhibited at 1-2 years of age?

Babinski reflex Signup and view all the answers

What is true about the stepping reflex?

It is inhibited around 3 months of age. Signup and view all the answers

Which of the following reflexes is both palmar and plantar?

Grasping reflex Signup and view all the answers

Which reflex is not present at birth but develops later?

Stepping reflex Signup and view all the answers

What initiates the detection of muscle stretching?

The tapping of the tendon Signup and view all the answers

What is the role of the sensory neuron in the reflex arc?

It transmits signals to the spinal cord Signup and view all the answers

What occurs after the sensory neuron synapses with the motor neuron in the spinal cord?

Action potentials cause the muscle to contract Signup and view all the answers

During the withdrawal reflex, what happens after the hand touches a hot pan?

Action potentials flow along pain sensory neurons Signup and view all the answers

What is the immediate consequence of pain neuron synapsing with other neurons in the spinal cord?

A motor response is triggered Signup and view all the answers

Which of the following statements about action potentials is true?

They are electrical signals that cause muscle contractions Signup and view all the answers

How is the withdrawal reflex described in terms of its complexity?

It is a complex reflex involving several synapses Signup and view all the answers

Which part of the nervous system primarily processes the sensory information from muscle stretching?

Spinal cord Signup and view all the answers

What is the primary role of noradrenaline in the sympathetic nervous system?

Causes the release of noradrenaline from the neuron Signup and view all the answers

Which of the following effects is associated with the sympathetic nervous system?

Increased heart rate Signup and view all the answers

During a sympathetic response, which action is most likely to occur?

Decreased motility of the digestive system Signup and view all the answers

What happens to the membrane potential during an excitatory signal?

It depolarizes, allowing an action potential to be generated Signup and view all the answers

Which receptor type is involved in pupil dilation during sympathetic activation?

Alpha adrenergic receptors Signup and view all the answers

In the context of neural integration, what primarily determines the final response of a neuron?

The strongest and/or longest lasting input Signup and view all the answers

What is the effect of the parasympathetic nervous system on heart rate?

It decreases heart rate Signup and view all the answers

During sympathetic system activation, which of the following would likely increase?

Glycogenolysis Signup and view all the answers

What is the function of interneurons in the nervous system?

They serve as a central integrator for sensory input Signup and view all the answers

Which neurotransmitter is primarily involved in the parasympathetic response?

Acetylcholine Signup and view all the answers

What determines whether the effect of a neurotransmitter on a post-synaptic neuron is excitatory or inhibitory?

The receptor present on the post-synaptic cell Signup and view all the answers

What happens to the post-synaptic neuron when both an excitatory and an inhibitory pre-synaptic cell are active simultaneously?

The outcome depends on the strength and duration of the inputs Signup and view all the answers

If an inhibitory pre-synaptic cell is activated for a longer duration than an excitatory one, what is likely to occur in the post-synaptic cell?

The neuron will remain hyperpolarized Signup and view all the answers

What action initiates the release of neurotransmitters from a neuron?

The arrival of an action potential at the axon terminal Signup and view all the answers

How does a single neuron typically integrate incoming signals from multiple pre-synaptic neurons?

By summing the excitatory and inhibitory inputs Signup and view all the answers

What is the primary effect of an excitatory neurotransmitter on a post-synaptic neuron?

Depolarization of the neuron Signup and view all the answers

Which division of the autonomic nervous system is directly responsible for both blood vessel constriction and heart rate increase?

Sympathetic Signup and view all the answers

During activation of the sympathetic division, tissues and organs receive:

Less blood flow Signup and view all the answers

Which receptor subtype would most likely be associated with coronary blood vessels during adrenergic activation?

Beta-2 Signup and view all the answers

What is the primary mechanism of action for a drug relieving bronchoconstriction during an asthma attack that acts on adrenergic receptors?

Activate adrenergic receptors Signup and view all the answers

Which drug would primarily act at cholinergic receptors to relieve bronchoconstriction?

An anticholinergic Signup and view all the answers

For a drug used to reduce blood pressure by acting on adrenergic receptors, what is its likely effect?

Vasodilation Signup and view all the answers

In the context of anaphylaxis, which type of adrenergic receptor is targeted to reverse bronchoconstriction and vasodilation?

Beta-2 Signup and view all the answers

What was the main neurotoxic agent used in the 1995 terrorist attack, and what is its effect?

Sarin gas, which inhibits neurotransmitter breakdown Signup and view all the answers

What type of inhibitor are organophosphates classified as?

Acetylcholinesterase inhibitors Signup and view all the answers

Which neurotransmitter does organophosphate poisoning cause to be in excess?

Acetylcholine Signup and view all the answers

What is a likely physiological effect of excess acetylcholine due to organophosphate poisoning?

Enhanced muscle contraction Signup and view all the answers

In the context of muscle physiology, what effect might organophosphate poisoning have on the respiratory system?

Muscle paralysis Signup and view all the answers

Which type of neurons are likely affected in Arnold's case based on his symptoms?

Motor neurons Signup and view all the answers

What symptom does Arnold exhibit that indicates a possible disruption in the reflex arc?

Weak ankle and knee reflexes Signup and view all the answers

What could be a consequence of the lumbar region injury that Arnie is facing?

Loss of proprioception Signup and view all the answers

Based on Arnold's condition, what can be inferred about the nature of his injury?

It may have compressed spinal nerves Signup and view all the answers

Study Notes

Neurotransmitters & Receptors

Neurotransmitters are crucial for communication in the nervous system, affecting various functions.
Key neurotransmitters include acetylcholine (ACh) for somatic (muscle) and autonomic functions, and others such as dopamine and serotonin in the CNS.
Disorders linked to neurotransmitter imbalance:
- Depression
- Schizophrenia
- Parkinson’s disease
- Mania
- Dementia

Treatment Strategies

Treatments for conditions often target neurotransmitter manipulation to alter receptor interactions.
Common antidepressant classes:
- Monoamine oxidase inhibitors (MAOIs)
- Selective serotonin reuptake inhibitors (SSRIs)
- Noradrenaline-serotonin reuptake inhibitors (NSRIs)
- Selective Noradrenaline reuptake inhibitors (SNRIs)
- Noradrenaline-dopamine reuptake inhibitors (NDRIs)

Mechanism of Action

Synaptic transmission ends through reuptake or enzymatic breakdown by MAO or COMT.
Prolonging neurotransmitter effects can be achieved by inhibiting their reuptake or blocking metabolic enzymes.

Side Effects of Treatments

Targeting neurotransmitters for one condition may produce side effects affecting other systems (e.g., nausea, hypertension).
Personalization of treatment is essential due to varying responses in neurotransmitter systems.

Autonomic Functions

Autonomic nervous system divides into:
- Sympathetic (fight or flight)
- Parasympathetic (rest and restore)
Key neurotransmitter: acetylcholine has nicotinic and muscarinic receptors influencing various organ functions.

Receptor Types

Cholinergic Receptors:
- Nicotinic: Found on skeletal muscles, induce contraction.
- Muscarinic: Located in the brain and organs, induce parasympathetic responses.
Adrenoceptors (for Noradrenaline):
- Subtypes include α and β receptors, influencing functions like blood vessel constriction and heart rate.

Reflexes and Integration

Reflex actions are quick, automatic responses that can involve multiple types of neurons, indicating integration in processing sensory inputs.
Excitatory signals lead to depolarization and action potential generation, while inhibitory signals lead to hyperpolarization preventing action potentials.

Neural Control Loops

Involves interaction between sensory (afferent) neurons, central integrators (CNS), and motor (efferent) neurons.
Detection of changes leads to appropriate motor responses.

Types of Reflexes

Reflexes can be somatic or autonomic, involving cranial or spinal nerves, and occur rapidly without conscious control.
Include primitive reflexes, such as the Moro, Babinski, and rooting reflexes, which are innate but may be overruled as one matures.

Pain Modulation

Stress-induced analgesia involves endogenous opioids that modify pain perception during extreme stress, limiting detrimental pain experiences.

Final Notes

Integration of diverse inputs is essential for coordinating a robust response, enabling the nervous system to efficiently process information.
Understanding neurotransmitters and reflex pathways provides a foundation for exploring complex neurological conditions and treatments.

Autonomic Receptors & Neurotransmitters

The sympathetic nervous system directly influences blood vessel constriction and heart rate.
Activation of the sympathetic system results in organs receiving less blood flow.
Adrenergic receptors (subtypes α and β) mediate both constriction and dilation of blood vessels depending on the receptor subtype activated.
Expect β2 adrenergic receptors on coronary blood vessels facilitating dilation.
Expect α1 adrenergic receptors on skeletal muscle and gastrointestinal tract blood vessels, promoting constriction and reducing blood flow.

Therapeutic Manipulation of the Nervous System

Bronchodilation during asthma: adrenergic β2 receptor agonists relieve symptoms.
Bronchodilation via cholinergic receptors involves antagonists to block excessive bronchoconstriction.
Drugs reducing blood pressure act on adrenergic receptors, often by blocking β1 receptors to decrease heart rate.
Adrenergic α1 receptor agonists can relieve nasal congestion through vasoconstriction.
Epinephrine, acting on adrenergic receptors, combats anaphylaxis by reversing histamine-triggered effects.

Case 1: Misuse of Autonomic Receptor Knowledge

Sarin gas inhibits acetylcholinesterase, leading to excess acetylcholine in the synapses.
Excess acetylcholine causes increased parasympathetic tone: potential effects include respiratory distress, muscle paralysis, and seizures.
Most deadly effect likely results from respiratory failure due to bronchoconstriction and mucus secretion.

Case 2: Trouble at the Gym

MRI may show herniated discs or spinal stenosis affecting lumbar nerves.
Symptoms suggest nerve root compression, resulting in pain, weakness, and sensory disturbances (pins and needles).
Reflex tests reveal affected lower motor neurons (lower limb) indicating nerve damage.

Integrating Information

Neurons release a specific neurotransmitter, influencing the post-synaptic cell based on receptor types.
The release process involves action potentials, calcium influx, and vesicle fusion at the synapse.
An excitatory pre-synaptic neuron increases post-synaptic excitability; an inhibitory pre-synaptic neuron decreases it.
When both excitatory and inhibitory inputs are active, they can potentially cancel each other out. The longer inhibition lasts may lead to diminished excitatory effects.

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Description

This quiz covers key concepts from Advanced Human Bioscience HUBS1416, focusing on neurotransmitters, receptors, and the integration of electrical signals in the central nervous system. Understand the roles of neurotransmitters and receptors in autonomic functions and reflex actions. Test your knowledge of synaptic processes and neural communication.