The sympathomedullary pathway | AQA A-Level Psychology Revision
- Revision Notes
- Aug 6
- 17 min read
Updated: Aug 14
For 7182 specification, first teach in September 2025
AQA A-Level Psychology | Free Revision Notes
Estimated study time: 55 minutes
These sympathomedullary pathway A-Level Psychology revision notes explain how the body produces a rapid physiological response to an immediate stressor. You will follow the pathway from the hypothalamus, through the sympathetic nervous system, to the adrenal medulla and the release of adrenaline and noradrenaline. The lesson links these changes to fight or flight and compares the pathway with the response to prolonged stress [The HPA system], helping you distinguish two processes that students frequently confuse.
Learning Objectives 🎯
By the end of this revision page, you should be able to:
Define the sympathomedullary pathway.
Describe the sequence of structures involved in the pathway.
Explain the roles of the sympathetic nervous system and adrenal medulla.
Explain how adrenaline and noradrenaline produce the fight-or-flight response.
Apply the pathway to an unfamiliar stressful situation.
Compare the sympathomedullary pathway with the HPA system.
Revision Notes 📚
What does the AQA specification require?
Within the Stress option, AQA requires students to study the physiology of stress, including:
General adaptation syndrome.
The hypothalamic-pituitary-adrenal system.
The sympathomedullary pathway.
The role of cortisol.
The specification also requires knowledge of the fight-or-flight response and the role of adrenaline within Biopsychology.
For this lesson, you need to understand:
How the pathway begins.
The role of the sympathetic nervous system.
The role of the adrenal medulla.
The release of adrenaline and noradrenaline.
How these hormones prepare the body for fight or flight.
How the pathway differs from the HPA system.
What is the sympathomedullary pathway?
The sympathomedullary pathway is the physiological pathway responsible for the body’s rapid response to an immediate stressor.
It is often abbreviated to the SAM pathway:
S refers to the sympathetic nervous system.
A refers to the adrenal glands.
M refers to the adrenal medulla.
The pathway combines activity in the nervous system and endocrine system.
Its essential sequence is:
Stressor → hypothalamus → sympathetic nervous system → adrenal medulla → adrenaline and noradrenaline → fight or flight
The pathway acts rapidly because an immediate threat may require the person to respond within seconds.
Why is a rapid response necessary?
An immediate threat may require urgent action.
Examples include:
A vehicle suddenly moving towards a pedestrian.
A person hearing an unexpected alarm.
An animal running towards someone.
A cyclist losing control.
A loud crash occurring nearby.
In such situations, the body needs to:
Detect the threat.
Mobilise energy.
Increase oxygen supply.
Prepare the muscles for action.
Respond before there is time for careful planning.
The sympathomedullary pathway produces these changes as part of the fight-or-flight response.
The sympathomedullary pathway step by step
Step 1: A stressor is detected
The process begins when a possible threat or demand is detected.
Information about the threat activates the hypothalamus, a brain structure involved in regulating bodily responses.
The hypothalamus coordinates the physiological stress response.
Step 2: The hypothalamus activates the sympathetic nervous system
The hypothalamus activates the sympathetic branch of the autonomic nervous system.
The autonomic nervous system controls involuntary bodily functions, such as:
Heart rate.
Breathing.
Digestion.
Blood pressure.
The sympathetic branch increases physiological arousal and prepares the body for action.
This is not a conscious decision. The person does not deliberately instruct their heart to beat faster.
Step 3: The sympathetic nervous system stimulates the adrenal medulla
Activity in sympathetic nerves reaches the adrenal medulla.
The adrenal medulla is the inner part of the adrenal gland.
The adrenal glands are located above the kidneys, but in an examination the most important distinction is between:
The adrenal medulla, involved in the sympathomedullary pathway.
The adrenal cortex, involved in the HPA system.
Step 4: The adrenal medulla releases adrenaline and noradrenaline
The adrenal medulla releases the hormones:
Adrenaline
Noradrenaline
These hormones enter the bloodstream and travel around the body.
AQA has directly assessed this distinction. The June 2024 mark scheme confirms that the sympathomedullary pathway involves the release of both adrenaline and noradrenaline.
Step 5: Physiological arousal increases
Adrenaline and noradrenaline produce bodily changes that prepare the person for immediate action.
These include:
Increased heart rate.
Increased breathing rate.
Increased blood pressure.
Increased availability of glucose for energy.
Greater blood supply to skeletal muscles.
Reduced activity in processes not immediately needed, such as digestion.
Increased alertness.
These changes support either confronting the threat or escaping from it.
Step 6: Fight or flight becomes possible
The body is now prepared for fight or flight.
Fight means confronting or resisting the threat.
Flight means escaping or moving away from the threat.
The physiological preparation is similar in both cases. The increased heart rate and breathing rate provide oxygen and energy for muscular activity.
The complete sequence
Stage | Structure or system | Action |
1 | Hypothalamus | Detects or responds to the stressor and activates the sympathetic nervous system |
2 | Sympathetic nervous system | Carries the rapid arousal response to the adrenal medulla |
3 | Adrenal medulla | Releases adrenaline and noradrenaline |
4 | Adrenaline and noradrenaline | Increase physiological arousal |
5 | Body organs and muscles | Become prepared for fight or flight |
A concise examination chain is:
The hypothalamus activates the sympathetic nervous system, which stimulates the adrenal medulla to release adrenaline and noradrenaline. These hormones increase physiological arousal and prepare the body for fight or flight.
The role of the hypothalamus
The hypothalamus initiates the pathway.
It is the starting point for both major physiological stress pathways:
The sympathomedullary pathway.
The HPA system.
However, the hypothalamus activates a different process in each pathway.
Sympathomedullary pathway | HPA system |
Hypothalamus activates sympathetic nervous activity | Hypothalamus releases corticotrophin-releasing hormone |
Produces a rapid response | Produces a slower, sustained response |
Leads to adrenaline and noradrenaline | Leads to cortisol |
📌 Exam tip: Saying only that “the hypothalamus is activated” is not a complete explanation. You must state what it activates or releases next.
The role of the sympathetic nervous system
The sympathetic nervous system is one branch of the autonomic nervous system.
Its role is to increase physiological arousal when the person faces a demand or threat.
It:
Receives activation from the hypothalamus.
Transmits signals to the adrenal medulla.
Produces immediate changes in bodily organs.
Supports the release of adrenaline and noradrenaline.
The sympathetic nervous system is closely associated with the idea of “revving up” the body.
The role of the adrenal medulla
The adrenal medulla is the inner section of each adrenal gland.
When stimulated by the sympathetic nervous system, it releases adrenaline and noradrenaline into the bloodstream.
This changes the response from neural communication to hormonal communication:
Sympathetic nerves carry rapid signals.
The adrenal medulla releases hormones.
The hormones travel in the blood.
Organs throughout the body respond.
The adrenal medulla is not the same as the adrenal cortex.
The role of adrenaline
Adrenaline is a hormone involved in the immediate fight-or-flight response.
Its effects include:
Increasing heart rate so blood circulates more rapidly.
Increasing breathing rate so more oxygen becomes available.
Increasing blood pressure.
Increasing the availability of energy.
Supporting blood flow to the muscles.
Reducing activity in digestion while immediate action is prioritised.
These effects are adaptive because they increase the person’s capacity to act quickly.
The AQA Biopsychology content also names the role of adrenaline in fight or flight, so knowledge from the biological response to immediate danger [Fight or flight] supports this lesson.
The role of noradrenaline
Noradrenaline is released alongside adrenaline during the sympathomedullary response.
It contributes to increased arousal, alertness and cardiovascular activity.
Students sometimes learn only adrenaline because the specification explicitly names its role in fight or flight. However, when asked specifically about the sympathomedullary pathway, remember that AQA has confirmed the release of both hormones.
A safe examination statement is:
The adrenal medulla releases adrenaline and noradrenaline, which increase physiological arousal and prepare the person for fight or flight.
How heart rate supports fight or flight
An increase in heart rate means that blood is pumped more rapidly around the body.
This helps:
Deliver oxygen to skeletal muscles.
Deliver glucose for energy.
Remove waste products produced by muscular activity.
Support rapid physical action.
For example, if a person needs to run from danger, the leg muscles require an increased supply of oxygen and energy.
How breathing rate supports fight or flight
An increased breathing rate allows the person to take in more oxygen.
The oxygen can then be transported in the blood to muscles that may be needed for:
Running.
Pushing.
Lifting.
Defending.
Escaping.
A developed answer links the physiological change to its function. Do not merely list “breathing increases”.
How glucose supports fight or flight
Glucose provides energy for bodily activity.
During the fight-or-flight response, increased energy availability allows muscles to work rapidly.
This is useful during an emergency because the person may need to respond before food could be eaten and digested.
Why digestion is reduced
Digestion is important, but it is not the body’s immediate priority during a sudden threat.
Resources are temporarily directed towards:
The heart.
The lungs.
The skeletal muscles.
Systems involved in rapid response.
Reduced digestive activity allows more resources to be used for immediate survival.
Fight or flight is an adaptive response
The fight-or-flight response is adaptive because it helps the person respond to danger.
For example:
A pedestrian hears a vehicle approaching quickly. Their heart and breathing rates increase, providing energy and oxygen so they can move out of its path.
The bodily response is useful because it increases the likelihood of a rapid, effective action.
However, the same physiological response can occur when the stressor does not require physical action, such as:
Waiting to give a presentation.
Hearing unexpected criticism.
Sitting an examination.
Receiving an alarming message.
The body may still prepare for fight or flight even when neither fighting nor running is appropriate.
Returning the body towards its resting state
Once the immediate threat has passed, continued high arousal is no longer useful.
The parasympathetic branch of the autonomic nervous system helps return the body towards its resting state.
This may involve:
Reducing heart rate.
Reducing breathing rate.
Lowering physiological arousal.
Restoring digestive activity.
Conserving energy.
The two branches have broadly opposing effects:
Sympathetic branch | Parasympathetic branch |
Increases arousal | Reduces arousal |
Prepares the body for action | Returns the body towards rest |
Associated with fight or flight | Associated with recovery |
Increases energy use | Conserves or restores energy |
Sympathetic and parasympathetic activity
The sympathetic and parasympathetic branches are not separate stress theories.
They are divisions of the autonomic nervous system with different roles:
The sympathetic branch produces arousal.
The parasympathetic branch supports recovery.
A useful memory cue is:
Sympathetic starts the emergency response, parasympathetic promotes recovery.
Applying the pathway to a scenario
Consider this example:
While cycling, Alex sees a car pull unexpectedly into the road. Alex’s heart begins pounding, breathing becomes faster and the leg muscles tense. After the car stops and the danger passes, Alex’s heart rate gradually returns towards normal.
A developed application would explain:
The car entering the road is the stressor.
Alex’s hypothalamus activates the sympathetic nervous system.
Sympathetic activity stimulates the adrenal medulla.
The medulla releases adrenaline and noradrenaline.
These hormones increase heart and breathing rates.
Increased oxygen and energy prepare Alex’s leg muscles for flight.
Once the danger passes, parasympathetic activity helps reduce arousal.
Application structure
Use this structure:
Scenario detail → physiological component → effect → purpose
For example:
Alex’s heart begins pounding because adrenaline increases heart rate. This circulates oxygen and glucose more quickly to the muscles, preparing Alex to move away from danger.
Avoid writing:
Alex’s fight-or-flight response happens because he is scared.
This identifies the situation but does not explain the physiological pathway.
Immediate and prolonged stress
The sympathomedullary pathway is most closely associated with immediate stress.
The HPA system is more closely associated with prolonged stress.
A stressor may activate both systems. For example:
A sudden emergency may activate the sympathomedullary pathway immediately.
If the situation continues, the HPA system may help sustain the response.
This connects with the stages of adaptation over time [General adaptation syndrome].
Comparing the sympathomedullary and HPA pathways
The two pathways share some features, but they must not be treated as interchangeable.
Feature | Sympathomedullary pathway | HPA system |
Main role | Immediate response to a stressor | Sustained response to prolonged stress |
Starting structure | Hypothalamus | Hypothalamus |
Next stage | Sympathetic nervous system | Pituitary gland |
Adrenal structure | Adrenal medulla | Adrenal cortex |
Main hormones | Adrenaline and noradrenaline | Cortisol |
Speed | Rapid | Slower |
Duration | Relatively short lived | Longer lasting |
Main outcome | Fight-or-flight arousal | Continued energy availability |
Type of communication | Neural activity followed by hormonal release | Endocrine chain of hormonal release |
Similarities between the pathways
Both pathways:
Begin with the hypothalamus.
Involve the adrenal glands.
Release hormones.
Increase the body’s ability to deal with a stressor.
Mobilise energy.
Are physiological responses rather than deliberate choices.
A comparison question requires both similarities and differences where appropriate.
Difference 1: Speed
The sympathomedullary pathway acts rapidly because it begins with activity in the sympathetic nervous system.
The HPA system is slower because it involves a chain of hormonal communication:
The hypothalamus releases CRH.
CRH stimulates the pituitary gland.
The pituitary releases ACTH.
ACTH stimulates the adrenal cortex.
The cortex releases cortisol.
The sequence for the prolonged pathway is explored fully in cortisol and continuing stress [The HPA system].
Difference 2: Part of the adrenal gland
The two pathways involve different regions:
Sympathomedullary pathway: adrenal medulla
HPA system: adrenal cortex
A strong comparison states both sides explicitly.
Do not write only:
“The sympathomedullary pathway uses the medulla.”
Instead write:
“The sympathomedullary pathway stimulates the adrenal medulla, whereas the HPA system stimulates the adrenal cortex.”
Difference 3: Hormones released
The sympathomedullary pathway releases:
Adrenaline.
Noradrenaline.
The HPA system releases:
Cortisol, following the actions of CRH and ACTH.
Remember:
Medulla means adrenaline and noradrenaline. Cortex means cortisol.
Difference 4: Duration of stress
The sympathomedullary pathway is suited to an immediate demand because it quickly prepares the body for action.
The HPA system supports a prolonged response by maintaining energy availability while the stressor continues.
For example:
Nearly being hit by a bicycle would strongly involve the sympathomedullary pathway.
Coping with months of workplace pressure would involve sustained HPA activation.
Difference 5: Effects on the body
The sympathomedullary pathway produces rapid increases in:
Heart rate.
Breathing rate.
Blood pressure.
Physical readiness.
The HPA system maintains the response through cortisol and may contribute to health problems if activation remains prolonged.
The next lesson examines the connection between prolonged physiological activation and disease [Stress and illness].
Writing an effective comparison
A comparison must place the pathways directly alongside one another.
A strong sentence is:
The sympathomedullary pathway produces a rapid response through sympathetic activation and the adrenal medulla, whereas the HPA system produces a slower response through the pituitary gland and adrenal cortex.
A weaker response is:
The SAM pathway releases adrenaline. The HPA system exists too.
The second response describes one pathway but does not establish a meaningful relationship between them.
Exam comparison checklist
For each comparison point:
Name the feature being compared.
State what happens in the sympathomedullary pathway.
State the corresponding feature of the HPA system.
Use a comparative word such as whereas, both, in contrast or similarly.
Useful categories include:
Speed.
Duration.
Adrenal structure.
Hormone.
Type of stress.
Route of communication.
Relationship with general adaptation syndrome
General adaptation syndrome describes how the stress response changes across the alarm, resistance and exhaustion stages.
The sympathomedullary pathway is particularly relevant to the alarm reaction, when the stressor is first detected and physiological resources are mobilised rapidly.
The HPA system is especially relevant when the stressor continues and the body enters resistance.
General adaptation syndrome stage | Relevant physiological response |
Alarm reaction | Rapid sympathomedullary activation |
Resistance | Continuing HPA activity and cortisol |
Exhaustion | Possible reduction in the body’s ability to sustain the response |
The models describe stress at different levels:
General adaptation syndrome describes stages over time.
The sympathomedullary and HPA pathways describe physiological mechanisms.
Using physiological measurements
The effects of the sympathomedullary pathway may be investigated by measuring:
Heart rate.
Blood pressure.
Breathing rate.
Skin conductance.
These measurements can indicate increased arousal, although they do not by themselves show exactly which stressor caused it.
This prepares you for objective indicators of physiological arousal [Physiological measures of stress].
Key Words 🔑
Key word | Student-friendly definition | How it may be used in an exam |
Sympathomedullary pathway | The rapid physiological pathway that prepares the body to respond to an immediate stressor | Describe the sequence from the hypothalamus to fight or flight |
SAM pathway | An abbreviation for the sympathomedullary pathway | Use only after writing the full term once |
Stressor | A demand, event or threat that activates a stress response | Identify what begins the pathway in a scenario |
Hypothalamus | A brain structure that activates the physiological stress response | State that it activates the sympathetic nervous system |
Autonomic nervous system | The part of the peripheral nervous system controlling involuntary bodily functions | Explain where the sympathetic and parasympathetic branches belong |
Sympathetic nervous system | The branch of the autonomic nervous system that increases physiological arousal | Explain how the adrenal medulla is activated |
Adrenal gland | An endocrine gland containing the cortex and medulla | Distinguish the roles of its two regions |
Adrenal medulla | The inner part of the adrenal gland that releases adrenaline and noradrenaline | Link it specifically to the sympathomedullary pathway |
Adrenal cortex | The outer part of the adrenal gland involved in cortisol release | Use it when comparing the pathway with the HPA system |
Adrenaline | A hormone that rapidly increases physiological arousal | Link increased heart rate and energy availability to fight or flight |
Noradrenaline | A hormone released with adrenaline that contributes to arousal and alertness | Include it when explaining the complete sympathomedullary response |
Fight or flight | The physiological preparation to confront or escape from a threat | Explain the purpose of increased arousal |
Physiological arousal | Increased bodily activity that prepares the individual to respond | Apply it to changes in heart rate, breathing or blood pressure |
Parasympathetic nervous system | The branch of the autonomic nervous system that returns the body towards resting activity | Explain recovery after the stressor ends |
HPA system | A slower pathway involving the hypothalamus, pituitary gland and adrenal cortex | Compare it with the rapid sympathomedullary pathway |
Cortisol | A hormone released by the adrenal cortex during prolonged stress | Contrast it with adrenaline and noradrenaline |
Hints from the Examiner Reports 💡
No lesson-specific examiner guidance was identified in the provided reports.
The reports do, however, identify examination techniques that are directly relevant to this lesson.
Examiner hint: Apply psychological knowledge rather than merely repeating a scenario. The 2021 report noted that weaker application answers often contained little psychological content. In this topic, name the structure, hormone and physiological effect rather than writing only that a person feels stressed.
Examiner hint: Make comparisons explicit. A previous report noted that students’ knowledge could be sound while direct comparison remained limited. Use paired statements containing words such as whereas and both.
Examiner hint: Learn both hormones released by the adrenal medulla. AQA’s 2024 assessment required students to recognise that the pathway involves both adrenaline and noradrenaline.
Examiner hint: Use precise specialist terminology. “Adrenal gland” may be too vague when the question requires a distinction between the medulla and cortex.
Examiner hint: Follow the command word. Explain requires connected cause and effect. Compare requires direct similarities or differences between both pathways.
Examiner hint: Use the whole scenario. Heart rate, breathing, muscular tension, speed of onset and recovery can each provide a separate application point.
Common Mistakes ⚠️
Mistake: Saying that the pathway begins with the adrenal gland.
Why this is incorrect:The pathway begins when the stressor activates the hypothalamus.
How to improve:Learn the sequence from its starting point: hypothalamus, sympathetic nervous system, adrenal medulla.
Mistake: Leaving out the sympathetic nervous system.
Why this is incorrect:The sympathetic nervous system connects hypothalamic activation with stimulation of the adrenal medulla.
How to improve:Include the nervous-system stage before naming the adrenal gland.
Mistake: Saying that the adrenal cortex releases adrenaline.
Why this is incorrect:Adrenaline and noradrenaline are released by the adrenal medulla. The cortex releases cortisol as part of the HPA system.
How to improve:Remember: medulla, immediate; cortex, continuing.
Mistake: Saying that only adrenaline is involved.
Why this is incorrect:AQA identifies both adrenaline and noradrenaline as part of the sympathomedullary pathway.
How to improve:Include both hormones whenever the full pathway is requested.
Mistake: Saying that noradrenaline is released by the pituitary gland.
Why this is incorrect:The pituitary releases ACTH in the HPA system. Noradrenaline is released from the adrenal medulla during the sympathomedullary response.
How to improve:Separate the hormone chains for the two pathways before revising them together.
Mistake: Linking the pathway to prolonged stress only.
Why this is incorrect:The sympathomedullary pathway is primarily associated with the immediate fight-or-flight response.
How to improve:Use the HPA system when explaining sustained cortisol release during a continuing stressor.
Mistake: Saying that fight or flight means the person must physically fight or run.
Why this is incorrect:Fight or flight describes physiological preparation. The person may experience this arousal even when neither action is taken.
How to improve:Explain the bodily response separately from the person’s eventual behaviour.
Mistake: Listing physiological changes without explaining their purpose.
Why this is incorrect:A list does not show how the changes help the person respond.
How to improve:Link each change to action, for example increased heart rate delivers oxygen and glucose to muscles.
Mistake: Confusing sympathetic and parasympathetic activity.
Why this is incorrect:The sympathetic branch increases arousal, while the parasympathetic branch helps reduce it.
How to improve:Remember: sympathetic starts the emergency response, parasympathetic promotes recovery.
Mistake: Describing the HPA system instead of comparing it.
Why this is incorrect:A comparison question requires both pathways to be related directly.
How to improve:Use paired points, such as medulla versus cortex and adrenaline versus cortisol.
Mistake: Saying both pathways release cortisol.
Why this is incorrect:Cortisol is part of the HPA pathway. The sympathomedullary pathway releases adrenaline and noradrenaline.
How to improve:Create a three-column revision table for pathway, adrenal region and hormone.
Mistake: Writing that the physiological response is consciously controlled.
Why this is incorrect:The pathway operates through the autonomic nervous and endocrine systems.
How to improve:Describe the response as automatic or involuntary.
Exam-Style Questions ✍️
Question 1
Which hormones are released from the adrenal medulla during activation of the sympathomedullary pathway?
A. Adrenaline and cortisolB. Adrenaline and noradrenalineC. ACTH and adrenalineD. Cortisol and noradrenaline
[1 mark]
Question 2
Define the sympathomedullary pathway.
[2 marks]
Question 3
Outline the sequence of activity in the sympathomedullary pathway.
[5 marks]
Question 4
Explain how adrenaline helps prepare the body for fight or flight.
[4 marks]
Question 5
While walking home, Erin hears a sudden crash behind her. Her heart begins pounding, her breathing becomes faster and the muscles in her legs tense.
Use the sympathomedullary pathway to explain Erin’s response.
[6 marks]
Question 6
Explain three differences between the sympathomedullary pathway and the HPA system.
[6 marks]
Question 7
A researcher records the following physiological measurements after participants hear an unexpected alarm.
Time of measurement | Mean heart rate, beats per minute | Mean breathing rate, breaths per minute |
Before the alarm | 70 | 14 |
One minute after the alarm | 116 | 27 |
Fifteen minutes after the alarm has stopped | 74 | 15 |
Use the sympathomedullary pathway to explain the pattern shown in the table.
[4 marks]
Question 8
Kofi narrowly avoids a collision while driving. His heart rate and breathing rate increase immediately. The incident leads to a lengthy dispute which continues for several months, during which Kofi remains tense and has difficulty sleeping.
Explain the physiological response to stress. Refer to the sympathomedullary pathway, the HPA system and Kofi in your answer.
[8 marks]
Answers and Mark Scheme
Question 1
Answer: B
The adrenal medulla releases both adrenaline and noradrenaline.
[1 mark]
Question 2
Award up to two marks:
The sympathomedullary pathway is a rapid physiological response to an immediate stressor.
It involves sympathetic activation of the adrenal medulla, leading to the release of adrenaline and noradrenaline.
[2 marks]
Question 3
Award one mark for each stage:
A stressor activates the hypothalamus.
The hypothalamus activates the sympathetic nervous system.
Sympathetic activity stimulates the adrenal medulla.
The adrenal medulla releases adrenaline and noradrenaline.
These hormones increase physiological arousal and prepare the body for fight or flight.
[5 marks]
Question 4
Award up to four marks:
Adrenaline is released by the adrenal medulla.
It increases heart rate.
It increases breathing rate or the availability of energy.
These changes provide oxygen and glucose to the muscles, preparing the person for physical action.
Credit other accurate effects clearly connected to fight or flight.
[4 marks]
Question 5
Award one mark for each clear application, up to six marks:
The sudden crash is the immediate stressor.
Erin’s hypothalamus activates the sympathetic nervous system.
The sympathetic nervous system stimulates the adrenal medulla.
The adrenal medulla releases adrenaline and noradrenaline.
Erin’s pounding heart and faster breathing show increased physiological arousal.
Increased oxygen and energy prepare her leg muscles for fight or flight.
Credit other accurate and developed applications.
[6 marks]
Question 6
Award up to two marks for each developed comparison:
The sympathomedullary pathway is rapid, whereas the HPA system is slower and more sustained.
The sympathomedullary pathway stimulates the adrenal medulla, whereas the HPA system stimulates the adrenal cortex.
The sympathomedullary pathway releases adrenaline and noradrenaline, whereas the HPA system releases cortisol.
The sympathomedullary pathway uses the sympathetic nervous system, whereas the HPA system uses a hormonal chain involving CRH and ACTH.
The sympathomedullary pathway is associated mainly with immediate stress, whereas the HPA system is associated mainly with prolonged stress.
Maximum [6 marks].
Question 7
Award up to four marks:
The large rise in heart rate and breathing rate one minute after the alarm indicates rapid physiological arousal.
The alarm activates the hypothalamus and sympathetic nervous system.
The adrenal medulla releases adrenaline and noradrenaline, increasing heart and breathing rates.
After the alarm ends, parasympathetic activity helps return both measurements towards their resting levels.
Answers should interpret the pattern rather than merely repeat the figures.
[4 marks]
Question 8
Indicative content may include:
Knowledge and understanding
An immediate stressor activates the hypothalamus.
The hypothalamus activates the sympathetic nervous system.
The sympathetic nervous system stimulates the adrenal medulla.
Adrenaline and noradrenaline are released.
Heart rate and breathing rate rise as part of fight or flight.
A continuing stressor activates the HPA system.
The hypothalamus releases CRH.
The pituitary gland releases ACTH.
The adrenal cortex releases cortisol.
Cortisol maintains energy availability during prolonged stress.
Application to Kofi
The near collision is an immediate stressor.
Kofi’s immediate rise in heart and breathing rates indicates sympathomedullary activation.
The response prepares him to act rapidly during the danger.
The dispute lasting several months is a prolonged stressor.
Continued tension is consistent with sustained HPA activation.
Cortisol may help Kofi continue responding while the dispute remains unresolved.
A high-level answer will explain both pathways accurately, apply them to different stages of Kofi’s experience and make the difference between immediate and prolonged stress explicit.
[8 marks]
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