SCSA Human Biology Endocrine system
9 sample questions with marking guides and sample answers · Avg. score: 60.3%
Two unrelated patients; X and Y, visited the same neurosurgeon. The patients had very similar names, and both had a form of brain damage. The neurosurgeon asked Patient X to complete a point-to-point movement test, where the index finger touches the nose and then touches the outstretched finger of the neurosurgeon. He was also asked to walk across the room while the neurosurgeon observed his stability. Patient X found this very strange, as these tests were not what he normally experienced. He has a benign growth below the hypothalamus, reducing levels of thyroid-stimulating hormone. When Patient X questioned this, the neurosurgeon realised he had mixed up the two patients and mistakenly thought he was seeing Patient Y.
Using the information above, identify the part of the brain damaged in both patients (X and Y), describe the role of these parts in normal body functioning and describe the effects damage to these structures would have on both patients.
Reveal Answer
An example response:
For patient X, the affected part is the anterior pituitary. Its role is to produce hormones, release hormones, and maintain homeostasis. The possible effects of damage include hypothyroidism, fatigue, and loss of appetite.
For patient Y, the affected part is the cerebellum, which coordinates voluntary motor movement and maintains balance. Possible effects of damage include weak muscles, slurred, speech, and abnormal eye movements.
Patient X
| Descriptor | Marks |
|---|---|
Identifies the affected part as the Anterior Pituitary | 1 |
1 mark for each correct point (any 2 of):
| 2 |
1 mark for each correct point (any 3 of):
| 3 |
Patient Y
| Descriptor | Marks |
|---|---|
Identifies the affected part as the Cerebellum | 1 |
1 mark for each correct point (any 2 of):
| 2 |
1 mark for each correct point (any 3 of):
| 3 |
Describe how the hypothalamus and pituitary work together to achieve their main function.
Reveal Answer
An example response:
Hormones are produced in the hypothalamus, and are transported down the axons. Hormones are stored in posterior lobe and released via nervous stimulation.
Hormones are produced in the anterior lobe Inhibiting and releasing factors secreted by hypothalamus determine the release of hormones. Blood vessels connect hypothalamus with the anterior lobe, and released via hormonal stimulation.
Posterior pituitary
| Descriptor | Marks |
|---|---|
States that hormones are produced (in cell bodies located) in the hypothalamus or not produced by the pituitary | 1 |
Describes that hormones are transported down the axons or neurosecretory cells | 1 |
States that hormones are stored in the posterior lobe | 1 |
Identifies that they are released via nervous stimulation | 1 |
Anterior pituitary
| Descriptor | Marks |
|---|---|
States that hormones are produced in the anterior lobe | 1 |
Explains that inhibiting and releasing factors secreted by the hypothalamus determine the release of hormones | 1 |
Describes that blood vessels (hypothalamic-hypophyseal portal system) connect the hypothalamus with the anterior lobe or that it travels in the blood | 1 |
Identifies that they are released via chemical or hormonal stimulation | 1 |
The target organ for the hormone calcitonin is the
parathyroid gland.
adrenal gland.
bones.
liver.
Reveal Answer
parathyroid gland.
The parathyroid gland secretes parathyroid hormone (PTH), which has the opposite effect of calcitonin by raising blood calcium levels, but it is not the target organ for calcitonin.
adrenal gland.
The adrenal glands produce hormones like cortisol and adrenaline for stress responses and metabolism, and are not involved in the calcium-regulating pathway of calcitonin.
bones.
Calcitonin primarily targets the bones, where it inhibits osteoclast activity to reduce bone resorption and effectively lower blood calcium levels.
liver.
While the liver is a major target for metabolic hormones like insulin and glucagon, it does not play a primary role in the calcium regulation mediated by calcitonin.
Which of the following lists endocrine glands that are not controlled directly by the hypothalamus?
pituitary, thymus, adrenal medulla
thymus, pancreas, adrenal cortex
parathyroid, pancreas, adrenal medulla
pancreas, thyroid, pituitary
Reveal Answer
pituitary, thymus, adrenal medulla
This option is incorrect because the pituitary gland is directly controlled by the hypothalamus via releasing/inhibiting hormones and direct neural connections.
thymus, pancreas, adrenal cortex
This option is incorrect because the adrenal cortex is heavily regulated by the hypothalamus through the hypothalamic-pituitary-adrenal (HPA) axis, even if this control is mediated by the pituitary gland.
parathyroid, pancreas, adrenal medulla
This is correct because the parathyroid is regulated by blood calcium levels, the pancreas by blood glucose levels, and the adrenal medulla by the sympathetic nervous system. None of these are directly controlled by the hypothalamus.
pancreas, thyroid, pituitary
This option is incorrect because the pituitary gland is directly controlled by the hypothalamus, which dictates the release of its hormones.
Use the following information to answer the question.
Growth hormone (GH) is a peptide hormone that is made by cells in the pituitary gland. GH is transported to the plasma membrane of the cells in the pituitary gland and then released into the blood. Liver cells respond to GH by secreting another hormone called insulin-like growth factor (IGF-1). IGF-1 stimulates muscle cells to increase in size and bone cells to produce mineralised bone. Fat cells respond to GH by breaking down triglycerides into fatty acids and glycerol.
The receptors that are responsible for detecting GH in liver cells and fat cells are located
in the cytosol.
within the nucleus.
on the plasma membrane.
on the nuclear membrane.
Reveal Answer
in the cytosol.
GH is a peptide hormone, meaning it is hydrophilic and cannot cross the cell membrane to bind to intracellular receptors in the cytosol.
within the nucleus.
Receptors within the nucleus are typically for lipid-soluble hormones (like steroids) that can cross the cell membrane, unlike the peptide hormone GH.
on the plasma membrane.
Because GH is a hydrophilic peptide hormone, it cannot cross the hydrophobic lipid bilayer of the cell and must bind to extracellular receptors located on the plasma membrane.
on the nuclear membrane.
Peptide hormones cannot enter the cell, so they cannot reach or bind to receptors located on the nuclear membrane.
Which of the following is the key difference between adrenaline and insulin?
Insulin
is secreted in response to a chemical stimulus, while adrenaline secretion is controlled by a nerve impulse.
controls blood sugar concentrations, while adrenaline helps regulate temperature.
is secreted by the pancreas, while adrenaline is secreted by the kidneys.
is a water-soluble hormone, while adrenaline is a lipid-soluble one.
Reveal Answer
is secreted in response to a chemical stimulus, while adrenaline secretion is controlled by a nerve impulse.
Insulin secretion is triggered by high blood glucose levels (a chemical stimulus), whereas adrenaline is released in response to sympathetic nerve impulses during the "fight-or-flight" response.
controls blood sugar concentrations, while adrenaline helps regulate temperature.
While insulin does regulate blood sugar, adrenaline is primarily involved in the body's stress response, not temperature regulation.
is secreted by the pancreas, while adrenaline is secreted by the kidneys.
Insulin is secreted by the pancreas, but adrenaline is secreted by the adrenal glands, which sit on top of the kidneys, rather than the kidneys themselves.
is a water-soluble hormone, while adrenaline is a lipid-soluble one.
Both insulin (a peptide hormone) and adrenaline (an amine hormone derived from tyrosine) are water-soluble hormones.
Target cells respond to specific hormones as a result of
nucleic acid binding sites in the membrane and cytoplasm.
specific binding sites on enzymes found in the cytoplasm.
carbohydrate receptors in the plasma membrane.
protein receptors in the plasma membrane and cytoplasm.
Reveal Answer
nucleic acid binding sites in the membrane and cytoplasm.
Hormone receptors are composed of proteins, not nucleic acids. Nucleic acids like DNA and RNA are involved in genetic information storage and transfer.
specific binding sites on enzymes found in the cytoplasm.
While some receptors have enzymatic activity, hormones do not generally bind to enzymes in the cytoplasm; they bind to dedicated receptor proteins.
carbohydrate receptors in the plasma membrane.
Hormone receptors are primarily protein molecules, not carbohydrates, although some membrane receptors may be glycoproteins with carbohydrate chains attached.
protein receptors in the plasma membrane and cytoplasm.
Target cells contain specific protein receptors either on the plasma membrane (for water-soluble hormones) or within the cytoplasm/nucleus (for lipid-soluble hormones) that allow them to detect and respond to hormones.
Production of the human growth hormone (hGH) is controlled by a gene. Lack of this hormone leads to dwarfism in humans.
hGH is released from the pituitary gland. State from which lobe of the pituitary this hormone is secreted and explain the relationship between this lobe of the pituitary gland and the hypothalamus.
Reveal Answer
It is secreted from the anterior lobe. Communication between the hypothalamus and the anterior pituitary occurs through chemicals through the infundibulum. The hypothalamus stimulates the anterior pituitary to release hormones via releasing factors. The hormones are released into a capillary network and transported through veins. The hypothalamus also produces inhibiting factors to inhibit the activity of the pituitary.
| Descriptor | Marks |
|---|---|
States that it is secreted from the anterior lobe | 1 |
Award 1 mark for each of the following points, up to a maximum of 5 marks:
| 5 |
hGH is a water-soluble hormone. Explain how hGH enters and affects the functioning of its target cell.
Reveal Answer
The hormone dissolves in water, not fats, so it cannot pass through the cell membrane. Instead, the hormone molecule attaches to a receptor molecule found on the surface of the target cell, and the receptor molecule must match the shape of the signalling molecule.
The binding of the hormone to the receptor triggers a response inside the cell. This secondary messenger activates enzymes inside the cytoplasm, which adjust the chemical activity of the cell, causing the speed of reactions to either increase or decrease.
| Descriptor | Marks |
|---|---|
Describes how the hormone enters the target cell. Award 1 mark for each of the following points, up to a maximum of 3 marks:
| 3 |
Describes how the hormone affects the target cell. Award 1 mark for each of the following points, up to a maximum of 3 marks:
| 3 |
Dwarfism can be treated using synthetically produced hGH. Explain how hGH could be produced using recombinant DNA technology.
Reveal Answer
The gene for hGH is located on a human chromosome and is treated with a restriction enzyme, which cuts DNA at specific sites. A plasmid is cut with the same restriction enzyme, and the gene is inserted into the plasmid using ligase. The plasmid acts as a vector and produces a transgenic organism. The recombinant plasmid enters into a host bacterial cell, which clones. The bacteria express the gene to synthesize the human protein, which produces large-scale amounts of hGH.
| Descriptor | Marks |
|---|---|
Award 1 mark for each of the following points, up to a maximum of 8 marks:
| 8 |
Christian, a 40-year-old man, was recently diagnosed with Type 2 diabetes. Christian was classified as obese according to his body mass index and his fasting blood glucose level was very high being measured at 10.3 mmol L. In addition to changes to his diet and increased exercise, Christian's doctor prescribed a drug to promote weight loss and lower Christian's blood glucose levels. This drug mimics a natural water-soluble hormone in the human body, enhancing the action of insulin and reducing glucagon levels.
Explain how the following glands maintain blood glucose levels during fasting: ...
Outline how water-soluble hormones influence their target cells.
Reveal Answer
They attach to receptor proteins in the membrane of the target cell, forming a hormone-receptor complex. This activates a secondary messenger inside the cytoplasm or cell, activating particular enzymes, and having a short-lived response.
| Descriptor | Marks |
|---|---|
States that they attach to receptor proteins in the membrane of the target cell | 1 |
Describes the formation of a hormone-receptor complex | 1 |
Explains that this activates a secondary messenger inside the cytoplasm/cell | 1 |
States that this activates particular enzymes/increases enzyme concentration | 1 |
Describes the response as having a fast onset/short-lived response | 1 |
... pancreas
Reveal Answer
Low blood glucose levels are detected by chemoreceptors, and the alpha cells are stimulated. Glucagon is secreted, stimulating glycogenolysis, which is the breakdown of glycogen to glucose, and gluconeogenesis, which is the production of glucose from amino acids and fats. Both of these processes primarily occur in the liver. It also stimulates lipolysis, the breakdown of fats, which occurs in most body cells or adipose tissue.
| Descriptor | Marks |
|---|---|
States that low blood glucose levels are detected | 1 |
Identifies that detection is by chemoreceptors | 1 |
States that the Islets of Langerhans/alpha cells are stimulated | 1 |
States that glucagon is secreted | 1 |
Describes the stimulation of glycogenolysis/breakdown of glycogen to glucose | 1 |
Describes the stimulation of gluconeogenesis/production of glucose from amino acids and fats | 1 |
States that both processes primarily occur in the liver | 1 |
Describes the stimulation of lipolysis/breakdown of fats | 1 |
States that lipolysis occurs in most body cells/adipose tissue | 1 |
... adrenal glands
Reveal Answer
The adrenal medulla secretes adrenaline/noradrenaline, and the adrenal cortex secretes cortisol. This further enhances the rate of glucose production, increasing blood glucose by gluconeogenesis/glycogenolysis.
| Descriptor | Marks |
|---|---|
1 mark for each correct point (any 3 of): States that the adrenal medulla secretes adrenaline/noradrenaline; States that the adrenal cortex secretes cortisol; Explains that this further enhances the rate of glucose production/increases blood glucose; Identifies that this occurs by gluconeogenesis/glycogenolysis | 3 |
Explain why a patient with Type 1 diabetes would not be prescribed the drug from the above scenario to manage their blood glucose levels.
Reveal Answer
Type 1 diabetes is the inability to produce insulin. The drug works to enhance insulin activity, so if there is no insulin being produced, the drug will have no effect.
| Descriptor | Marks |
|---|---|
Defines Type 1 diabetes as the inability to produce insulin | 1 |
States that the drug works to enhance insulin activity | 1 |
Concludes that if there is no insulin being produced, the drug will have no effect | 1 |
Changes to the amount of thyroxine being released from the thyroid gland can have major impacts on the functioning of the body.
Name each of the disorders that may lead to an over-secretion or under-secretion of thyroxine; describe how the over-secretion or under-secretion impacts on the body; and explain how each disorder can be treated.
Reveal Answer
Hypothyroidism is a disorder where low levels of thyroxine lead to a decrease in metabolic rate. This causes symptoms such as decreased heart rate and decreased blood pressure. Treatments include increasing iodine in the diet, taking synthetic hormone tablets, or surgery.
Conversely, hyperthyroidism is a disorder where high levels of thyroxine lead to overstimulation of body cells. This causes symptoms such as increased heart rate and high blood pressure. Treatments include taking drugs to block the thyroid's use of iodine, surgery to remove all or part of the gland, or radioactive iodine.
Disorder Identification
| Descriptor | Marks |
|---|---|
Identifies Hypothyroidism/Hashimoto's disease | 1 |
Identifies Hyperthyroidism/Graves' disease | 1 |
Impacts
| Descriptor | Marks |
|---|---|
Describes that low levels of thyroxine lead to a decrease in metabolic rate causing symptoms | 1 |
Describes that high levels of thyroxine lead to overstimulation of body cells causing symptoms | 1 |
Symptoms
| Descriptor | Marks |
|---|---|
1 mark for each correct point (any 2 of) for Hypothyroidism:
| 2 |
1 mark for each correct point (any 2 of) for Hyperthyroidism:
| 2 |
Treatments
| Descriptor | Marks |
|---|---|
1 mark for each correct point (any 2 of) for Hypothyroidism:
| 2 |
1 mark for each correct point (any 2 of) for Hyperthyroidism:
| 2 |
Explain the role of the liver in the maintenance of blood glucose levels.
Reveal Answer
Glucose is removed from blood to provide energy for liver functioning.
Glucose also converted to glycogen by the process of glycogenesis controlled by insulin, and glycogen is stored in the liver.
When blood sugar levels fall glycogen is converted back to glucose by the process of glycogenolysis, which is controlled by glucagon
| Descriptor | Marks |
|---|---|
glucose removed from blood to provide energy for liver functioning | 1 |
glucose also converted to glycogen | 1 |
by the process of glycogenesis | 1 |
controlled by insulin | 1 |
glycogen is stored in the liver | 1 |
when blood sugar levels fall glycogen is converted back to glucose | 1 |
by the process of glycogenolysis | 1 |
controlled by glucagon | 1 |