L3 - G-Protein Coupled Receptors 2

Question 1

What is the fight or flight response?

Answer 1

The fight or flight response is a physiological reaction to a perceived threat, which prepares the body to either fight or flee from danger. It was originally developed to protect us from predators but is now often triggered by acute stress such as before an important exam or presentation.

Question 2

What are the key components involved in the fight or flight response?

Answer 2

The fight or flight response involves the brain, sympathetic nervous system (SNS), and the adrenal medulla. These components work together to activate various physiological changes that prepare the body for action.

Question 3

How does adrenaline increase oxygen uptake during the fight or flight response?

Answer 3

Adrenaline increases oxygen uptake by:

Increasing airway diameter: This allows for easier airflow into the lungs, enhancing oxygen intake.
Increasing respiratory rate: This helps to increase the amount of oxygen brought into the body with each breath.

Question 4

Why is oxygen delivery important in the fight or flight response?

Answer 4

Oxygen delivery is crucial as it provides the energy needed by key organs, such as the brain, skeletal muscle, cardiac muscle, and liver, to function optimally during stressful or dangerous situations.

Question 5

How does adrenaline increase glucose delivery during the fight or flight response?

Answer 5

Adrenaline increases glucose delivery by:

Increasing glucose release into the bloodstream: This provides energy for the body’s vital organs and muscles.
Decreasing glucose uptake from the bloodstream into adipose tissue: This ensures more glucose is available for immediate use by muscles and the brain.

Question 6

How does adrenaline increase the delivery of oxygen and glucose to key organs?

Answer 6

Adrenaline increases the delivery of oxygen and glucose by:

Increasing heart rate: This ensures faster blood circulation to deliver oxygen and glucose more quickly to vital organs and muscles.
Increasing contractile force: This boosts the heart’s pumping ability, enhancing blood flow to organs like the brain, skeletal and cardiac muscles, and the liver.

Question 7

How does adrenaline direct the flow of oxygen and glucose to key organs?

Answer 7

Adrenaline directs the flow by:

Increasing the diameter of blood vessels supplying key organs: This allows for more oxygen and glucose to be delivered to vital organs like the brain, skeletal & cardiac muscles, and the liver.
Decreasing the diameter of blood vessels supplying non-essential organs: This diverts blood away from less critical organs (like the digestive system) to prioritize key organs during a stress response.

Question 8

What happens when adrenaline binds to β1/2-adrenoceptors?

Answer 8

Adrenaline binding activates the Gs protein.

Question 9

What does the activated Gs protein do?

Answer 9

The activated Gs protein stimulates adenylate cyclase.

Question 10

What does adenylate cyclase do?

Answer 10

Adenylate cyclase converts ATP to cAMP (cyclic AMP).

Question 11

What is the role of cAMP?

Answer 11

cAMP activates Protein kinase A (PKA).

Question 12

What does Protein kinase A (PKA) do?

Answer 12

PKA phosphorylates target proteins, leading to cellular changes like increased heart rate (β1) or bronchodilation (β2).

Question 13

What type of receptor does adrenaline act on in the fight or flight response?

Answer 13

Adrenaline acts on the α-1 adrenoceptor.

Question 14

What G-protein is associated with the α-1 adrenoceptor?

Answer 14

The α-1 adrenoceptor is coupled with the Gq protein.

Question 15

What enzyme does Gq activate in the α-1 adrenoceptor signaling pathway?

Answer 15

Gq activates phospholipase C (PLC).

Question 16

What molecule is generated by phospholipase C (PLC) activation?

Answer 16

PLC generates inositol trisphosphate (IP3) and diacylglycerol (DAG).

Question 17

What is the effect of IP3 on intracellular calcium?

Answer 17

IP3 stimulates the release of Ca²⁺ from the endoplasmic reticulum (ER).

Question 18

How does DAG contribute to the signaling pathway?

Answer 18

DAG activates protein kinase C (PKC), leading to various cellular responses.

Question 19

What is the overall result of the α-1 adrenoceptor activation in the fight or flight response?

Answer 19

The activation of the α-1 adrenoceptor triggers a series of intracellular events, leading to the release of calcium from the ER and the activation of PKC, contributing to the fight or flight response.

Question 20

What type of molecule is GTP in the context of the α-1 adrenoceptor signaling pathway?

Answer 20

GTP is a molecular switch that activates the Gq protein

Question 21

What does the acronym “PIP2” refer to in the signaling cascade?

Answer 21

PIP2 (phosphatidylinositol 4,5-bisphosphate) is the substrate cleaved by PLC to generate IP3 and DAG.

Question 22

What receptor does IP3 bind to in the signaling cascade?

Answer 22

IP3 binds to the IP3 receptor (IP3 R) on the endoplasmic reticulum to release Ca²⁺.

Question 23

How does adrenaline increase the delivery of oxygen and glucose to key organs?

Answer 23

Adrenaline increases oxygen and glucose delivery by enhancing the function of key organs such as the brain, skeletal and cardiac muscles, and the liver.

Question 24

How does adrenaline increase oxygen uptake?

Answer 24

Adrenaline increases oxygen uptake by increasing airway diameter and respiratory rate.

Question 25

What is the effect of increased airway diameter in the presence of adrenaline?

Answer 25

Increased airway diameter allows for greater airflow, improving oxygen intake and the removal of carbon dioxide.

Question 26

What role does the increased respiratory rate play in oxygen uptake?

Answer 26

Increased respiratory rate enhances oxygen intake and accelerates the removal of carbon dioxide.

Question 27

How does adrenaline affect myosin light chain (MLC) in muscle contraction?

Answer 27

Adrenaline activates the β2-adrenoceptor, leading to the activation of Gs, which increases cAMP levels and activates protein kinase A (PKA). PKA then phosphorylates and inactivates myosin light chain kinase (MLCK), preventing muscle contraction.

Question 28

What is the role of myosin light chain kinase (MLCK) in smooth muscle contraction?

Answer 28

MLCK normally phosphorylates myosin light chain (MLC), which leads to smooth muscle contraction.

Question 29

How does adrenaline lead to smooth muscle relaxation?

Answer 29

Adrenaline binds to the β2-adrenoceptor, activates Gs, increases cAMP levels, activates PKA, which inactivates MLCK, preventing the phosphorylation of MLC, leading to smooth muscle relaxation.

Question 30

What is the outcome of smooth muscle relaxation in the bronchioles?

Answer 30

Relaxation of smooth muscle in the bronchioles results in their dilation, improving airflow and gas exchange, contributing to increased oxygen uptake and carbon dioxide removal.

Question 31

What is the effect of increased cAMP levels in the presence of adrenaline?

Answer 31

Increased cAMP levels activate PKA, which phosphorylates MLCK, inhibiting its action and causing smooth muscle relaxation.

Question 32

What is the overall effect of adrenaline on bronchiole smooth muscle?

Answer 32

Adrenaline leads to bronchiole smooth muscle relaxation through the β2-adrenoceptor, resulting in bronchodilation and improved gas exchange, contributing to enhanced oxygen uptake and carbon dioxide removal.

Question 33

How does adrenaline increase the delivery of glucose to key organs?

Answer 33

Adrenaline increases glucose delivery by increasing glucose release into the bloodstream and decreasing glucose uptake into adipose tissue.

Question 34

How does adrenaline increase glucose levels in the blood?

Answer 34

Adrenaline increases glucose levels by stimulating the release of glucose from the liver into the bloodstream.

Question 35

What effect does adrenaline have on glucose uptake in adipose tissue?

Answer 35

Adrenaline decreases the uptake of glucose from the bloodstream into adipose tissue.

Question 36

How does the increase in glucose in the bloodstream benefit key organs during the fight or flight response?

Answer 36

The increased glucose in the bloodstream provides key organs, such as the brain, skeletal and cardiac muscles, and the liver, with the necessary energy to respond to stress or danger.

Question 37

What are the two key processes involved in elevating blood glucose levels during the metabolic changes induced by adrenaline?

Answer 37

The two key processes are increased lipid breakdown (lipolysis) in adipose tissue and increased glucose release from the liver.

Question 38

How does adrenaline affect adipose tissue during the metabolic response?

Answer 38

Adrenaline increases lipid breakdown (lipolysis) in adipose tissue and decreases glucose uptake from the bloodstream.

Question 39

How does the liver contribute to increasing blood glucose levels?

Answer 39

The liver increases blood glucose levels by increasing glycogen breakdown and enhancing gluconeogenesis.

Question 40

What is the result of increased glycogen breakdown in the liver?

Answer 40

Increased glycogen breakdown in the liver results in the release of glucose into the bloodstream.

Question 41

What role does gluconeogenesis play in increasing blood glucose levels?

Answer 41

Gluconeogenesis in the liver generates new glucose molecules, which are released into the bloodstream, further elevating blood glucose levels.

Question 42

What is the overall effect of these metabolic changes during the fight or flight response?

Answer 42

The metabolic changes increase blood glucose levels, providing essential energy to key organs, including the brain, skeletal and cardiac muscles, and the liver.

Question 43

How does adrenaline affect cardiac rate and contractility?

Answer 43

Adrenaline activates β1-adrenergic receptors (β1-AR) in the heart, leading to increased cardiac rate (chronotropic effect) and contractile force (ionotropic effect).

Question 44

What is the role of PKA in myocardial contraction?

Answer 44

PKA phosphorylates calcium channels, increasing their opening and leading to higher intracellular calcium levels.

Question 45

How does increased calcium contribute to myocardial contraction?

Answer 45

Increased calcium levels enhance both the cardiac rate (chronotropic effect) and the force of contraction (ionotropic effect), resulting in greater cardiac output.

Question 46

What is the overall effect of adrenaline on cardiac output?

Answer 46

Adrenaline increases cardiac output by enhancing cardiac rate and contractility, improving the delivery of oxygen and glucose to key organs such as the brain, skeletal and cardiac muscles, and the liver.

Question 47

How does the β1-adrenergic receptor signaling pathway increase calcium in cardiac tissue?

Answer 47

β1-AR activation stimulates adenylate cyclase (AC), increasing cAMP levels, which activate PKA. PKA then phosphorylates calcium channels, resulting in increased intracellular calcium concentration.

Question 48

What is the effect of increased calcium levels in the heart?

Answer 48

Increased calcium levels lead to stronger heart contractions (ionotropic effect) and faster heart rate (chronotropic effect), boosting cardiac output.

Question 49

How does adrenaline direct the flow of oxygen and glucose to key organs?

Answer 49

Adrenaline directs the flow of oxygen and glucose by enhancing blood flow to key organs such as the brain, skeletal and cardiac muscles, and the liver while redirecting blood away from less critical areas.

Question 50

What effect does adrenaline have on the smooth muscles of blood vessels?

Answer 50

Adrenaline causes smooth muscle relaxation in blood vessels supplying critical organs, leading to vasodilation, and contraction in non-essential areas, leading to vasoconstriction.

Question 51

How does adrenaline influence glucose availability to key organs?

Answer 51

Adrenaline increases glucose availability by stimulating glycogen breakdown in the liver and decreasing glucose uptake in adipose tissue, ensuring glucose is available for critical organs.

Question 52

What happens to blood flow in response to adrenaline during the fight or flight response?

Answer 52

Blood flow is increased to vital organs such as the brain, heart, and muscles, while blood flow is reduced to less critical areas, optimizing energy delivery during stress.

Question 53

How does adrenaline affect blood flow to key organs?

Answer 53

Adrenaline increases blood flow to key organs by binding to β2-adrenoceptors on the smooth muscle of arterioles supplying these organs.

Question 54

What happens when adrenaline binds to β2-adrenoceptors on smooth muscle?

Answer 54

Binding of adrenaline to β2-adrenoceptors activates adenylate cyclase, increasing cAMP levels, which activate PKA and lead to the phosphorylation and inactivation of myosin light chain kinase (MLCK), causing smooth muscle relaxation.

Question 55

What is the effect of MLCK inactivation on blood flow?

Answer 55

Inactivation of MLCK prevents the phosphorylation of myosin light chain (MLC), leading to smooth muscle relaxation, which allows more blood to flow to key organs.

Question 56

What is the role of PKA in regulating blood flow during the fight or flight response?

Answer 56

PKA phosphorylates MLCK, leading to its inactivation, which causes smooth muscle relaxation and increases blood flow to vital organs.

Question 57

How does cAMP contribute to the regulation of blood flow?

Answer 57

cAMP, produced by adenylate cyclase in response to adrenaline binding to β2-adrenoceptors, activates PKA, which in turn causes the relaxation of smooth muscle and increases blood flow to key organs.

Question 58

How does adrenaline affect peripheral blood vessels (BV)?

Answer 58

Adrenaline binds to α1-adrenoceptors, activating Gq and increasing IP3 levels, which leads to vasoconstriction in peripheral blood vessels.

Question 59

What is the role of IP3 in smooth muscle contraction?

Answer 59

IP3 increases intracellular calcium levels by releasing calcium from the sarcoplasmic reticulum (SR).

Question 60

What does released calcium bind to in smooth muscle contraction?

Answer 60

Released calcium binds to calmodulin (CaM), forming a Ca²⁺-CaM complex.

Question 61

How does the Ca²⁺-CaM complex affect myosin light chain kinase (MLC-K)?

Answer 61

The Ca²⁺-CaM complex activates myosin light chain kinase (MLC-K), which phosphorylates myosin light chain (Myosin-LC), resulting in smooth muscle contraction.

Question 62

What is the effect of smooth muscle contraction on blood flow?

Answer 62

Smooth muscle contraction leads to vasoconstriction, reducing blood flow to non-essential organs, such as the GI tract and kidneys.

Question 63

What is the overall effect of adrenaline on blood flow to non-essential organs?

Answer 63

Adrenaline causes vasoconstriction in peripheral blood vessels, reducing blood flow to non-essential organs and prioritizing blood flow to key organs like the brain, heart, and muscles.

Question 64

What is music performance anxiety (MPA)?

Answer 64

Music performance anxiety (MPA) is when musicians find it difficult to perform in front of others, particularly audiences.

Question 65

How is MPA classified in terms of severity?

Answer 65

MPA is a continuum of severity, where performance may be improved, worsened, or even impossible due to anxiety, and symptoms vary from person to person.

Question 66

How is MPA classified in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5)?

Answer 66

MPA is classified as a subtype of social anxiety disorder, specifically the performance-only subtype.

Question 67

Can anxiety affect musical performance in different ways?

Answer 67

Yes, anxiety can either improve performance, hinder it, or make it impossible for the musician to play, depending on the severity and the individual.

Question 68

What are the main physiological symptoms of music performance anxiety (MPA)?

Answer 68

The main physiological symptoms of MPA include tachycardia, sweating, tremor, blurred vision, and increased rate and depth of breathing.

Question 69

How does tachycardia manifest in MPA?

Answer 69

Tachycardia in MPA is characterized by an abnormally fast heart rate, often due to anxiety during performance.

Question 70

What role does sweating play in MPA?

Answer 70

Sweating is a common physiological response to anxiety, indicating the body's stress reaction during performance.

Question 71

How does tremor affect musicians with MPA?

Answer 71

Tremor refers to involuntary shaking or trembling, often occurring in the hands or body, making it difficult to play an instrument.

Question 72

What causes blurred vision in MPA?

Answer 72

Blurred vision in MPA can occur as a result of heightened anxiety, leading to physical changes in vision and focus.

Question 73

How does increased breathing rate and depth affect musicians with MPA?

Answer 73

Increased rate and depth of breathing occur as part of the body's "fight or flight" response, which can lead to hyperventilation during anxiety-provoking situations like performing.

Question 74

What are some common physical symptoms of music performance anxiety (MPA)?

Answer 74

Common physical symptoms of MPA include tremor, sweating, increased heart rate and contractility, shortness of breath, sweaty palms, and shaking hands.

Question 75

How does MPA affect oxygen uptake and glucose delivery?

Answer 75

MPA triggers an increase in oxygen uptake and glucose delivery to muscles, as part of the body’s "fight or flight" response.

Question 76

What effect do beta-blockers, such as propranolol, have on MPA symptoms?

Answer 76

Beta-blockers reduce peripheral sympathetic responses by blocking beta-adrenoceptors, which helps decrease physical symptoms like sweating, tremor, tachycardia, and rapid breathing, but they do not affect the emotional component of anxiety.

Question 77

Why is propranolol used for MPA?

Answer 77

Propranolol is used to alleviate the physical symptoms of anxiety, such as tremors and tachycardia, but it does not address the emotional or affective aspects of anxiety.

Question 78

How does beta-blocker use help musicians with MPA?

Answer 78

Beta-blockers reduce the physical symptoms like trembling hands and sweaty palms, making it easier for musicians, particularly violinists, to perform.

Question 79

What is the effect of MPA on energy levels in muscles?

Answer 79

MPA increases energy in muscles by enhancing oxygen and glucose delivery, preparing the body for action, but this can also contribute to feelings of physical tension or discomfort during performance.

Question 80

How does adrenaline increase the delivery of oxygen and glucose to key tissues?

Answer 80

Adrenaline increases oxygen and glucose delivery by enhancing blood flow to key tissues such as the brain, skeletal muscles, and the liver during the fight or flight response.

Question 81

What are the key tissues that receive increased oxygen and glucose during the fight or flight response?

Answer 81

The key tissues include the brain, skeletal muscles, and the liver.

Question 82

What physical symptoms can result from adrenaline’s action in the fight or flight response?

Answer 82

Physical symptoms include tremor and sweating, as part of the body’s heightened stress response.

Question 83

What is the overall effect of adrenaline on the body during the fight or flight response?

Answer 83

Adrenaline boosts oxygen and nutrient delivery to critical organs, preparing the body for rapid action, but can also trigger physical symptoms like tremor and sweating.