Neural Balance Quiz Neural Equilibrium Quiz
Grade 11 Biology: Homeostasis & The Nervous System
Name:
Date:
Section I: Concept Check
1. Which of the following best describes the role of an effector in a negative feedback loop?
A) It detects changes in the external environment.
B) It interprets sensory information and determines the response.
C) It carries out the response to restore the system to its set point.
D) It acts as a bridge between the central and peripheral nervous systems.
2. During an action potential, what causes the rapid depolarization of the neuron's membrane?
A) Potassium channels opening and \(K^+\) exiting the cell.
B) Sodium channels opening and \(Na^+\) entering the cell.
C) The sodium-potassium pump switching off.
D) Calcium ions binding to the axon terminal.
3. Which division of the nervous system is responsible for the "rest and digest" response?
A) Sympathetic Nervous System
B) Parasympathetic Nervous System
C) Somatic Nervous System
D) Central Nervous System
Section II: Structural Anatomy
Label the parts of the motor neuron indicated below. For each part, provide a brief description of its function.
1 2 3 4
1. Name:
Function:
2. Name:
Function:
3. Name:
Function:
4. Name:
Function:
Section III: Process Analysis
5. Homeostatic Mechanics (5 marks)
Imagine a person steps outside into -10°C weather. Using the terms Sensor, Control Center, and Effector , describe the negative feedback loop that maintains their body temperature.
6. The Synaptic Leap (5 marks)
Describe the steps that occur once an action potential reaches the axon terminal of a presynaptic neuron, leading to the initiation of a signal in the postsynaptic neuron.
7. The Reflex Arc (4 marks)
Why does a reflex (like pulling your hand away from a hot stove) happen faster than a voluntary movement (like picking up a glass of water)? Mention the neural pathway involved.
Section IV: Critical Evaluation
"Diabetes mellitus is a condition where the body cannot effectively regulate blood glucose levels."
Explain how this condition represents a failure of homeostasis . Identify which part of the feedback loop (Sensor, Control Center, or Effector) is typically compromised in Type 1 Diabetes and why. (6 marks)
Neural Balance Answer Key Answer Key: Neural Equilibrium
Grade 11 Biology: Homeostasis & The Nervous System
Teacher Resource
Section I: Concept Check (3 Marks)
C - The effector carries out the physical response to return the parameter to the set point.
B - Sodium channels open, allowing \(Na^+\) to rush into the negatively charged interior.
B - The parasympathetic system slows heart rate and promotes digestion.
Section II: Structural Anatomy (8 Marks)
1. Dendrites
Function: Receive signals (neurotransmitters) from other neurons or sensory receptors and conduct electrical impulses toward the cell body.
2. Cell Body (Soma)
Function: Contains the nucleus and organelles; integrates incoming signals and maintains the neuron's metabolic processes.
3. Myelin Sheath / Schwann Cell
Function: Insulates the axon to increase the speed of electrical impulse conduction (saltatory conduction).
4. Axon Terminals / Synaptic Knobs
Function: Store and release neurotransmitters into the synaptic cleft to transmit the signal to the next cell.
Section III: Process Analysis (14 Marks)
5. Temperature Negative Feedback Loop (5 Marks)
Sensor: Thermoreceptors in the skin or hypothalamus detect a drop in blood/external temperature. (1 mark)Control Center: The Hypothalamus processes the information and compares it to the set point (approx 37°C). (1 mark)Effector: Skeletal muscles (shivering), blood vessels (vasoconstriction), or hair follicles (piloerection). (2 marks for mentioning two)Result: Body temperature rises back toward the set point, shutting off the response. (1 mark)
6. Synaptic Transmission Steps (5 Marks)
Action potential reaches the terminal, causing calcium channels to open. (1 mark)
Calcium influx triggers synaptic vesicles to fuse with the presynaptic membrane. (1 mark)
Neurotransmitters are released into the synaptic cleft via exocytosis. (1 mark)
Neurotransmitters diffuse across the gap and bind to specific receptors on the postsynaptic membrane. (1 mark)
Ion channels open in the postsynaptic neuron, causing a graded potential (EPSP or IPSP). (1 mark)
7. Reflex Arc vs. Voluntary Movement (4 Marks)
Reflexes are faster because they bypass the brain for the immediate motor response (1 mark). The pathway is the **reflex arc** (1 mark), which involves only the sensory neuron, interneuron in the spinal cord, and motor neuron (1 mark). Voluntary movements require the signal to travel to the brain's cortex for processing and decision-making, which involves more synapses and a longer path (1 mark).
Kidney Filter Quiz Kidney Filter Quiz
Grade 11 Biology: Excretory System & The Nephron
Name:
Date:
Section I: Renal Fundamentals
1. What is the primary function of the Loop of Henle?
A) To filter large proteins out of the blood.
B) To create an osmotic gradient in the renal medulla.
C) To secrete urea into the collecting duct.
D) To transport urine from the kidney to the bladder.
2. Which hormone is released by the posterior pituitary when blood osmolarity is too high?
A) Insulin
B) Epinephrine
C) Antidiuretic Hormone (ADH)
D) Aldosterone
3. Where does the majority of selective reabsorption (glucose, amino acids) occur?
A) Proximal Convoluted Tubule
B) Distal Convoluted Tubule
C) Glomerulus
D) Renal Pelvis
Section II: The Functional Unit
Label the parts of the nephron indicated below. For each part, provide the name and describe the primary physiological process that occurs there.
1 2 3 4
1. Name:
Process/Function:
2. Name:
Process/Function:
3. Name:
Process/Function:
4. Name:
Process/Function:
Section III: Process Analysis
5. Thirst & Hormones (5 marks)
Explain the negative feedback loop involved when a student gets dehydrated during a gym class. Start from the Hypothalamus and end with the concentration of urine .
6. Filtration vs. Secretion (4 marks)
Distinguish between filtration and secretion in the nephron. Which substances are typically filtered, and which are specifically secreted?
Section IV: Clinical Case
"A patient presents with high blood pressure. They are prescribed a 'diuretic' medication, which inhibits the reabsorption of sodium ions (\(Na^+\)) in the Distal Convoluted Tubule."
Explain how inhibiting sodium reabsorption leads to increased urine volume and decreased blood pressure . Use the principle of osmosis in your answer. (6 marks)
Kidney Filter Answer Key Answer Key: Kidney Filter
Grade 11 Biology: Excretory System & The Nephron
Teacher Resource
Section I: Renal Fundamentals (3 Marks)
B - The Loop of Henle uses a counter-current multiplier to establish high salt concentrations in the medulla.
C - ADH (Vasopressin) increases the permeability of the collecting duct to water.
A - The PCT is the primary site where glucose and amino acids are actively reabsorbed back into the peritubular capillaries.
Section II: The Functional Unit (4 Marks)
1. Glomerulus / Bowman’s Capsule
Process: Non-selective pressure filtration of plasma (forming filtrate).
2. Proximal Convoluted Tubule (PCT)
Process: Active reabsorption of salts, glucose, and amino acids.
3. Loop of Henle (Descending & Ascending Limbs)
Process: Water reabsorption (descending) and sodium/chloride reabsorption (ascending).
4. Collecting Duct
Process: Hormonally-regulated water reabsorption and final urine concentration.
Section III: Process Analysis (9 Marks)
5. ADH Feedback Loop (5 Marks)
Hypothalamus detects high blood osmolarity (low water). (1 mark)It signals the posterior pituitary to release ADH into the bloodstream. (1 mark)
ADH travels to the Collecting Duct , increasing its permeability (opening aquaporins). (1 mark)
More water is reabsorbed back into the blood from the filtrate. (1 mark)
Result: Blood pressure rises, blood osmolarity lowers, and urine volume decreases/becomes more concentrated . (1 mark)
6. Filtration vs. Secretion (4 Marks)
Filtration: Occurs at the glomerulus. It is a non-selective process driven by blood pressure that forces plasma into Bowman's capsule (e.g., salts, water, urea, nutrients). Large items like cells and proteins remain in the blood. (2 marks)
Secretion: Occurs at the tubules (mainly DCT). It is a selective, active process that moves specific substances from the peritubular capillaries into the filtrate (e.g., \(H^+\) ions, potassium, excess drugs, creatinine). (2 marks)
Section IV: Clinical Case (6 Marks)
Sample Response Guide:
Mechanism: Inhibiting \(Na^+\) reabsorption means more sodium remains in the filtrate (inside the nephron). (2 marks) Hormonal Balance Quiz Hormonal Balance Quiz
Grade 11 Biology: Stress Response & Reproduction
Name:
Date:
Section I: Endocrine Essentials
1. Which part of the adrenal gland is responsible for the rapid "fight or flight" response by releasing epinephrine and norepinephrine?
A) Adrenal Cortex
B) Adrenal Medulla
C) Pancreas
D) Hypothalamus
2. In the male reproductive system, which hormone is directly responsible for stimulating sperm production (spermatogenesis) in the seminiferous tubules?
A) Luteinizing Hormone (LH)
B) Follicle-Stimulating Hormone (FSH)
C) Progesterone
D) Cortisol
3. During the menstrual cycle, what event is triggered by a sudden surge in Luteinizing Hormone (LH)?
A) Menstruation (shedding of the lining)
B) Development of the follicle
C) Ovulation (release of the egg)
D) Release of FSH
Section II: Hormonal Feedback
Complete the feedback loop table by identifying the hormone and its primary target or effect in the stress and reproductive systems.
Stimulus / Gland
Hormone(s)
Effect / Target Organ
Long-term stress (ACTH from Pituitary)
Interstitial cells (stimulated by LH)
Post-ovulatory Ovary (Corpus Luteum)
Section III: Stress Response Analysis
4. Short-term vs. Long-term Stress (5 marks)
Differentiate between the **Short-term** and **Long-term** stress responses. In your answer, identify the primary hormones involved and explain how they affect blood glucose levels differently.
5. Cortisol and the Pituitary (4 marks)
Cortisol is regulated by a **negative feedback loop**. Explain how a high concentration of cortisol in the blood affects the production of CRH (Hypothalamus) and ACTH (Pituitary).
Section IV: Reproductive Integration
"The menstrual cycle is a complex interaction of pituitary and ovarian hormones."
6. Describe the role of **Estrogen** in the proliferative phase of the menstrual cycle. How does it affect both the uterine lining and the production of LH? (5 marks)
7. What happens to the levels of **Progesterone** and **Estrogen** if fertilization does NOT occur? Explain how this change leads to the start of a new cycle. (4 marks)
Hormonal Balance Answer Key Answer Key: Hormonal Balance
Grade 11 Biology: Stress Response & Reproduction
Teacher Resource
Section I: Endocrine Essentials (3 Marks)
B - The adrenal medulla produces the rapid catecholamine (epinephrine/norepinephrine) response.
B - FSH stimulates sperm production, while LH stimulates testosterone production.
C - The LH surge (around day 14) triggers ovulation.
Section II: Hormonal Feedback (6 Marks)
Stimulus / Gland
Hormone(s)
Effect / Target Organ
Long-term stress (ACTH)
Cortisol / Glucocorticoids
Increases blood glucose via protein/fat metabolism; suppresses immune system.
Interstitial cells (by LH)
Testosterone
Promotes secondary male sex characteristics (beard, deepening voice, etc.)
Post-ovulatory Ovary (Corpus Luteum)
Progesterone (and Estrogen)
Maintains the thickened endometrium; inhibits LH and FSH.
Section III: Stress Response Analysis (9 Marks)
4. Short-term vs. Long-term Differentiation (5 Marks)
Short-term: Mediated by **Adrenaline/Epinephrine** (1 mark). Increases blood glucose rapidly by converting glycogen to glucose in the liver (1 mark).Long-term: Mediated by **Cortisol** (1 mark). Increases blood glucose more slowly by converting non-carbohydrates (proteins and fats) into glucose (gluconeogenesis) (1 mark).Comparison: Adrenaline is part of a nervous system impulse; Cortisol is part of a slower hormonal pathway via ACTH (1 mark).
5. Negative Feedback of Cortisol (4 Marks)
When cortisol levels in the blood are high (1 mark), the cortisol acts as an inhibitory signal (negative feedback) (1 mark). It travels to the Hypothalamus , decreasing the release of CRH (1 mark), and to the Anterior Pituitary , decreasing the release of ACTH (1 mark), thereby reducing further cortisol production.
Section IV: Reproductive Integration (9 Marks)
6. Role of Estrogen (5 Marks):
Stimulates the thickening/proliferation of the endometrium (uterine lining) in preparation for potential pregnancy. (2 marks)
At moderate levels, it has a negative feedback on FSH. (1 mark)
At peak levels (pre-ovulation), it switches to a positive feedback effect on the pituitary. (1 mark)
Metabolic Control Quiz Metabolic Control Quiz
Grade 11 Biology: Endocrine Regulation of Growth & Metabolism
Name:
Date:
Section I: Metabolic Mechanisms
1. Which hormone is primarily responsible for increasing the rate of cellular respiration and oxygen consumption throughout the body?
A) Insulin
B) Thyroxine (T4)
C) Human Growth Hormone (hGH)
D) Glucagon
2. What is the effect of Human Growth Hormone (hGH) on lipid (fat) metabolism?
A) It stimulates the storage of fat in adipose tissue.
B) It promotes the breakdown of fats (lipolysis) to provide energy for growth.
C) It has no effect on fat metabolism.
D) It converts excess glucose into fatty acids.
3. Which gland secretes Thyroid-Stimulating Hormone (TSH) in response to signals from the hypothalamus?
A) Thyroid Gland
B) Adrenal Cortex
C) Anterior Pituitary Gland
D) Posterior Pituitary Gland
Section II: Glucose Regulation
The pancreas contains Islets of Langerhans which regulate blood sugar. Identify the hormone produced and its primary action for each scenario below.
Condition
Hormone Released
Primary Action in Liver/Cells
Immediately after a high-carb meal
After a 12-hour fast (starvation)
Section III: The Thyroid Axis
4. The Metabolic Thermostat (5 marks)
Describe the negative feedback loop that maintains thyroxine levels in the blood. Include the roles of the Hypothalamus (TRH) and Anterior Pituitary (TSH) .
5. hGH and Tissue Growth (4 marks)
Explain how Human Growth Hormone (hGH) influences the growth of skeletal and muscular tissues. What role does it play in protein synthesis?
Section IV: Clinical Applications
Case A: Hyperthyroidism
A patient is diagnosed with Graves' disease, which causes excessive production of thyroxine. List three physiological symptoms the patient might experience and explain why these symptoms occur based on the hormone's function. (4 marks)
Case B: Growth Anomalies
Contrast the conditions of Gigantism and Acromegaly . Both are caused by excessive hGH; what determines which condition a patient develops? (4 marks)
Metabolic Control Answer Key Answer Key: Metabolic Control
Grade 11 Biology: Endocrine Regulation of Growth & Metabolism
Teacher Resource
Section I: Metabolic Mechanisms (3 Marks)
B - Thyroxine is the body's primary metabolic hormone.
B - hGH promotes fat breakdown to release energy needed for growth processes.
C - The anterior pituitary releases TSH after stimulation by TRH from the hypothalamus.
Section II: Glucose Regulation (4 Marks)
Condition
Hormone
Primary Action
Post-meal (High Sugar)
Insulin (Beta Cells)
Promotes uptake of glucose by cells and conversion of glucose to glycogen in liver.
Starvation (Low Sugar)
Glucagon (Alpha Cells)
Promotes the breakdown of glycogen into glucose (glycogenolysis) in the liver.
Section III: Process Analysis (9 Marks)
4. Thyroxine Negative Feedback (5 Marks)
Hypothalamus: Detects low thyroxine levels and releases TRH . (1 mark)Anterior Pituitary: Responds to TRH by releasing TSH into the blood. (1 mark)Thyroid Gland: Responds to TSH by releasing thyroxine (T4) . (1 mark)Action: Thyroxine increases cellular metabolic rate. (1 mark)Feedback: Rising thyroxine levels inhibit the production of TRH and TSH, closing the loop. (1 mark)
5. hGH and Protein Synthesis (4 Marks)
hGH promotes growth by increasing the uptake of amino acids from the blood (1 mark). It stimulates protein synthesis within cells, which is necessary for muscle and bone repair/growth (1 mark). In bones, it stimulates the elongation of long bones at the epiphyseal plates (1 mark). It also shifts the body towards using fats for energy, sparing glucose and protein for growth (1 mark).
Section IV: Clinical Case Guide (8 Marks)
Case A: Graves' Disease (4 Marks)
Symptoms: Weight loss, high body temperature/sweating, high heart rate/anxiety, protrusion of eyes (exophthalmos). (2 marks for naming two)
Explanation: Excess thyroxine dramatically increases the basal metabolic rate. Weight loss occurs because fuel is burned too quickly; high temperature occurs because heat is a byproduct of high metabolism. (2 marks)
Case B: Gigantism vs. Acromegaly (4 Marks)
Neural Command Quiz Neural Command Quiz
Grade 11 Biology: Brain Structure & Functional Hierarchy
Name:
Date:
Section I: Command Center
1. Which lobe of the cerebrum is primarily responsible for processing visual information?
A) Frontal Lobe
B) Temporal Lobe
C) Occipital Lobe
D) Parietal Lobe
2. Damage to the **Medulla Oblongata** would most likely lead to issues with which of the following?
A) Coordination of fine motor skills and balance.
B) Involuntary life-support functions like breathing and heart rate.
C) Thinking, reasoning, and problem-solving.
D) Sorting and relaying sensory information to the cerebrum.
3. What is the name of the bundle of nerve fibers that connects the left and right hemispheres of the brain?
A) Cerebral Cortex
B) Corpus Callosum
C) Thalamus
D) Meninges
Section II: Brain Anatomy
Label the major structures of the human brain indicated in the diagram. Identify the structure based on the provided function.
1 2 3 4
1. Structure:
Function: High-level cognitive functions, sensory processing, and motor control.
2. Structure:
Function: Coordination of balance, posture, and precise muscle movements.
3. Structure:
Function: Regulates autonomic activities such as heartbeat and respiration.
4. Structure:
Function: Acts as a relay station for sensory information or manages homeostasis.
Section III: System Hierarchy
5. Structural Divisions (4 marks)
Distinguish between the **Central Nervous System (CNS)** and the **Peripheral Nervous System (PNS)**. What anatomical components make up each division?
6. Somatic vs. Autonomic (4 marks)
Explain the functional difference between the **Somatic Nervous System** and the **Autonomic Nervous System**. Provide one example of an action controlled by each.
7. Protecting the Command Center (4 marks)
The brain and spinal cord are extremely delicate. Describe **two ways** (anatomical structures or substances) that the CNS is protected from physical injury or infection.
Section IV: Patient Case File
Case Study #042
"A patient arrives at the clinic following a sports injury. They are conscious but show significant difficulty in coordinating their movements and maintaining balance while walking, though their muscles are still strong."
Neural Command Answer Key Answer Key: Neural Command
Grade 11 Biology: Brain Structure & Functional Hierarchy
Teacher Resource
Section I: Command Center (3 Marks)
C - The occipital lobe is the primary visual processing center.
B - The medulla is critical for essential life functions like heart rate and respiration.
B - The corpus callosum allows communication between the two hemispheres.
Section II: Brain Anatomy (8 Marks)
1. Cerebrum (Cerebral Cortex)
Largest part of the brain; manages thought, memory, and voluntary movement.
2. Cerebellum
Coordinates balance and muscle tone; allows for complex, rhythmic motor patterns.
3. Medulla Oblongata (or Brainstem)
Connects brain to spinal cord; controls vital autonomic reflexes (swallowing, breathing).
4. Thalamus / Hypothalamus
Relays sensory signals (Thalamus) or maintains internal homeostasis via pituitary control (Hypothalamus).
Section III: System Hierarchy (12 Marks)
5. CNS vs. PNS (4 Marks)
The CNS (Central Nervous System) is the processing center, consisting of the Brain and Spinal Cord (2 marks). The PNS (Peripheral Nervous System) consists of all the nerves outside the CNS that connect the brain/cord to the rest of the body (2 marks).
6. Somatic vs. Autonomic (4 Marks)
The Somatic System controls voluntary movements of skeletal muscles (1 mark). Example: Walking (1 mark). The Autonomic System controls involuntary, automatic activities like heart rate and digestion (1 mark). Example: Heart beating during sleep (1 mark).
7. Protection (4 Marks)
Any two from the following (2 marks each):
Skull/Vertebrae: Hard bone provides physical armor.Meninges: Three layers of protective membrane.Cerebrospinal Fluid (CSF): Acts as a shock absorber/cushion.Blood-Brain Barrier: Selectively prevents chemicals/pathogens in blood from reaching the brain.
Section IV: Patient Case File Guide (6 Marks)
Case Study Resolution:
Structure Affected: The **Cerebellum** (2 marks). Because the patient has trouble with balance and coordination despite muscle strength, the issue is with the coordination center, not the motor output. Vital Balance Unit Test Vital Balance Unit Test
Grade 11 Biology: Cumulative Assessment (Nervous, Endocrine, Excretory)
Name:
Date:
Section I: System Integration
Match the homeostatic interaction with the primary organ system components involved. Some may use multiple systems.
___ 1. Detection of high salt in blood leading to thirst.
___ 2. Release of insulin to lower glucose after a meal.
___ 3. Reabsorbing water via aquaporins in the kidney.
___ 4. Increasing blood pressure via vasoconstriction (Stress).
A. Renal System (Nephron)
B. Endocrine System (Pancreas/Beta Cells)
C. Nervous System (Hypothalamus)
D. Endocrine System (Adrenal Medulla)
Section II: Nephron Concentration
5. Use the diagram below (Nephron anatomy) to answer the questions. (8 marks)
A B C
A. At point A, why can cells and proteins NOT enter the nephron?
B. At point B, is the filtrate concentration HYPO- or HYPER-tonic to the blood? Why?
6. High Glucose Levels (4 marks)
In patients with untreated Diabetes, glucose is often found in the urine. Explain why the Proximal Convoluted Tubule fails to reabsorb all the glucose in this situation.
Section III: Synthesis & Case Study
7. The Dehydration Effect (5 marks)
Alcohol is known to inhibit the release of Antidiuretic Hormone (ADH) from the pituitary. Explain the step-by-step effect this has on the Collecting Duct and the final volume and concentration of urine.
8. Aldosterone and Electrolytes (5 marks)
The hormone Aldosterone (released from the Adrenal Cortex) stimulates the nephron to reabsorb Sodium ions (\(Na^+\)) . How does this hormone help the body regulate **Blood Pressure**? Mention the role of water in your answer.
Section IV: The Big Picture
"Homeostasis is not the responsibility of a single organ system, but a coordinated effort."
9. Choose one of the following scenarios and explain how at least two organ systems (Nervous, Endocrine, or Excretory) work together to restore balance. (8 marks)
Scenario A: Extreme dehydration during an endurance race.
Scenario B: Sudden "Fight or Flight" during a high-stress event.
Vital Balance Answer Key Answer Key: Vital Balance Synthesis
Grade 11 Biology: Cumulative Unit Assessment
Teacher Resource
Section I: System Integration (4 Marks)
C - Hypothalamus detects blood osmolarity.
B - Pancreatic beta cells release insulin.
A - Occurs in the collecting duct of the nephron.
D - Epinephrine from the adrenal medulla triggers vasoconstriction.
Section II: Nephron Concentration (12 Marks)
5. Diagram Analysis (8 Marks)
A (Glomerulus): Cells and proteins cannot enter because they are too large to pass through the fenestrations (pores) of the glomerular capillaries and the podocyte slits. (4 marks)
B (Bottom of Loop): The filtrate is HYPER-tonic (highly concentrated) to the blood. (2 marks). This is because water has been reabsorbed into the hyper-saline medulla from the descending limb, while solutes remained inside the tubule. (2 marks)
6. Glucose Threshold (4 Marks)
The PCT uses **carrier proteins** (active transport) to reabsorb glucose. In diabetes, the blood glucose concentration is so high that these carrier proteins become **saturated** (reach their maximum transport rate). Any excess glucose cannot be reabsorbed and remains in the filtrate to be excreted in urine. (4 marks)
Section III: Synthesis Analysis (10 Marks)
7. Dehydration and ADH (5 Marks)
Alcohol inhibits ADH release from the pituitary. (1 mark)
Without ADH, the **Collecting Duct** becomes less permeable to water (aquaporins close). (2 marks)
Water remains in the tubule instead of being reabsorbed. (1 mark)
Result: High volume, very dilute urine; body becomes dehydrated. (1 mark)
8. Aldosterone and Pressure (5 Marks)
Aldosterone stimulates the active reabsorption of \(Na^+\) in the DCT and collecting duct (1 mark). Due to the osmotic gradient, water follows the salt back into the blood (2 marks). This increases blood volume (1 mark), which directly leads to an increase in blood pressure (1 mark).
Section IV: Big Picture Essay Rubric (8 Marks)
Evaluation Criteria:
System 1 (3 marks): Correct identification of first system's role (e.g., Hypothalamus/Nervous detecting osmotic change).System 2 (3 marks): Correct identification of second system's role (e.g., Pituitary/Endocrine releasing ADH or Renal/Excretory altering permeability).
