The correct answer isD. Dry skin.

Decreased thyroid function due to aging, also known as hypothyroidism, is a condition where the thyroid gland does not produce enough thyroid hormones.

Thyroid hormones regulate the body’s metabolism, temperature, and other functions.When there is not enough thyroid hormone, the body’s processes slow down and cause various symptoms.

Some of the symptoms of hypothyroidism in the elderly are:.

• Fatigue.

• Weight gain.

• Cold intolerance.

• Constipation.

• Dry skin.

• Hair loss.

• Muscle weakness.

• Joint pain.

• Depression.

• Memory problems.

Dry skin is a common symptom of hypothyroidism because thyroid hormones affect the skin’s moisture and elasticity.Low thyroid hormone levels can reduce the production of natural oils and cause the skin to become dry, flaky, and itchy.

Choice A is wrong becausetachycardia, or fast heart rate, is not a symptom of hypothyroidism.In fact, hypothyroidism can causebradycardia, or slow heart rate, because thyroid hormones affect the heart’s contractility and rhythm.

Choice B is wrong becauseweight lossis not a symptom of hypothyroidism.

On the contrary, hypothyroidism can causeweight gainbecause thyroid hormones regulate the body’s metabolism and energy expenditure.Low thyroid hormone levels can reduce the basal metabolic rate and cause the body to store more fat.

Choice C is wrong becauseheat intoleranceis not a symptom of hypothyroidism.

Instead, hypothyroidism can causecold intolerancebecause thyroid hormones affect the body’s temperature regulation and thermogenesis.Low thyroid hormone levels can reduce the production of heat and cause the body to feel cold.

The normal ranges for thyroid function tests are:.

• TSH: 0.4 - 4.0 mIU/L.

• Free T4: 0.8 - 1.8 ng/dL.

• Free T3: 2.3 - 4.2 pg/mL.

However, these ranges may vary depending on the laboratory and the population.Some studies suggest that the upper limit of normal for TSH may be higher in older adults.

Therefore, it is important to interpret thyroid function tests in the context of clinical symptoms and other factors.

The correct answer is A, B, and C.

Here is why:.

• A.“You may need to increase your insulin dosage as you get older.” This is true because ageing can impair insulin secretion and action, leading to increased insulin resistance and reduced glucose tolerance.Additionally, ageing can affect the absorption, metabolism, and excretion of insulin and other medications, which may require dose adjustments.

• B.“You may experience more episodes of hypoglycemia as you get older.” This is true because ageing can impair the counter-regulatory response to hypoglycemia, which is the release of hormones such as glucagon, epinephrine, cortisol, and growth hormone that raise blood glucose levels.Older adults with diabetes may also have reduced awareness of hypoglycemic symptoms, such as sweating, trembling, hunger, and confusion.

• C.“You may have less energy and feel more tired as you get older.” This is true because ageing can reduce the production and activity of several hormones that affect energy metabolism, such as thyroid hormones, growth hormone, and sex hormones.

These hormones regulate basal metabolic rate, muscle mass, fat distribution, and physical performance.Reduced energy levels can also affect glucose control and quality of life in older adults with diabetes.

• D.“You may develop osteoporosis due to decreased growth hormone production.” This is false because osteoporosis is mainly caused by decreased estrogen or testosterone production in women and men, respectively.

Estrogen and testosterone are important for maintaining bone mass and preventing bone resorption.Growth hormone has a minor role in bone metabolism compared to sex hormones.

• E.“You may have difficulty coping with stress due to decreased cortisol production.” This is false because cortisol production does not decrease with ageing.

Cortisol is the main stress hormone that helps the body adapt to various challenges.In fact, ageing can increase cortisol levels due to chronic inflammation, psychological stress, or impaired feedback regulation.Elevated cortisol levels can have negative effects on glucose control, cardiovascular health, and cognitive function in older adults with diabetes.

Normal ranges for some hormones in older adults are:.

• Thyroid-stimulating hormone: 0.4–4.0 mIU/L.

• Free thyroxine: 9–19 pmol/L.

• Growth hormone: < 5 ng/mL.

• Insulinlike growth factor 1: 50–216 ng/mL.

• Cortisol: 5–25 mcg/dL.

• Testosterone: 300–1000 ng/dL (men), 15–70 ng/dL (women).

• Estradiol: < 20 pg/mL (men), < 10 pg/mL (women).

The correct answer is A.

“Your wound may take longer to heal because of decreased inflammatory response.” Aging affects the immune system in several ways, such as:.

• The immune system becomes less able to distinguish self from nonself, which increases the risk of autoimmune disorders.

• Macrophages, which ingest bacteria and other foreign cells, destroy them more slowly, which may contribute to the higher incidence of cancer among older people.

• T cells, which remember antigens they have previously encountered, respond less quickly to them.There are also fewer white blood cells capable of responding to new antigens.

• The production of B and T cells in bone marrow and thymus is reduced, which affects the adaptive immunity.

• The function of lymph nodes and spleen is impaired, which reduces the ability to mount an effective immune response.

These changes result in a decreased inflammatory response, which is essential for wound healing.Inflammation helps to clear the infection, recruit immune cells, and promote tissue repair.

Therefore, older people may have slower wound healing due to aging of the immune system.

Choice B is wrong because aging does not increase nerve sensitivity.In fact, nerve endings may deteriorate with age, leading to reduced sensation and pain perception.

Choice C is wrong because aging does not decrease platelet aggregation.

Platelets are blood cells that help with clotting and prevent bleeding.Platelet function may be altered by aging, but not necessarily reduced.

Choice D is wrong because aging does not increase blood flow.Blood flow may decrease with age due to various factors, such as atherosclerosis, hypertension, and diabetes.Reduced blood flow may impair wound healing by limiting oxygen and nutrient delivery to the injured tissue.

The correct answer is C.

“Your T-cells become less effective and respond slower to antigens.”.

Some possible explanations for the answer are:.

• T-cells are a type of white blood cell that help the immune system fight infections by recognizing and destroying foreign invaders such as bacteria, viruses and cancer cells.

• Aging affects the immune system by causing several changes in the production, function and diversity of T-cells.These changes include thymic involution, mitochondrial dysfunction, genetic and epigenetic alterations, loss of proteostasis, reduction of the T-cell receptor (TCR) repertoire, naive-memory imbalance, T-cell senescence and lack of effector plasticity.

• Thymic involution is the gradual shrinking of the thymus gland, which is where T-cells mature and learn to distinguish self from non-self.This leads to a decrease in the number and quality of naive T-cells, which are essential for responding to new antigens.

• Mitochondrial dysfunction is the impairment of the energy-producing organelles in the cells, which affects the survival, activation and differentiation of T-cells.Aging causes oxidative stress, DNA damage and reduced autophagy in the mitochondria, which compromise their function and induce apoptosis or cell death.

• Genetic and epigenetic alterations are changes in the DNA sequence or expression of genes that regulate T-cell development, activation and function.Aging causes accumulation of mutations, chromosomal abnormalities and epigenetic modifications such as DNA methylation and histone acetylation in T-cells, which affect their gene expression and signaling pathways.

• Loss of proteostasis is the disruption of the balance between protein synthesis, folding, trafficking and degradation in the cells, which affects the quality and quantity of proteins involved in T-cell function.Aging causes increased protein misfolding, aggregation and degradation in T-cells, which impair their antigen recognition, cytokine production and cell cycle regulation.

• Reduction of the TCR repertoire is the decrease in the diversity and specificity of the receptors that recognize antigens on the surface of T-cells.

Aging causes clonal expansion of memory T-cells and contraction.

The correct answer is B. Decreased sodium level.

This is because decreased adrenal function due to aging can lead to lower levels of aldosterone, a hormone that regulates sodium and potassium balance in the body.Lower aldosterone levels can cause sodium loss and potassium retention, resulting in hyponatremia (low sodium) and hyperkalemia (high potassium).

Choice A is wrong because decreased adrenal function due to aging can cause lower levels of cortisol, a hormone that regulates glucose metabolism and stress response.Lower cortisol levels can cause hypoglycemia (low glucose) and impaired ability to cope with stress.

Choice C is wrong because decreased adrenal function due to aging can cause higher levels of potassium, as explained above.

Choice D is wrong because decreased adrenal function due to aging can cause lower levels of glucose, as explained above.

Normal ranges for sodium, potassium, cortisol and glucose are:.

• Sodium: 135-145 mEq/L.

• Potassium: 3.5-5.0 mEq/L.

• Cortisol: 5-25 mcg/dL (morning); 3-16 mcg/dL (afternoon).

• Glucose: 70-110 mg/dL (fasting); <140 mg/dL (2 hours after meal).