Anatomy and Physiology II (M8) Comprehensive Lecture Exam

Correct Answer: C. Thyroid gland

Explanation of the Correct Answer:

C. Thyroid gland

The thyroid gland is anatomically located in the anterior neck, just inferior (below) to the larynx (voice box) and anterior (in front of) the trachea. It is a butterfly-shaped endocrine gland composed of two lobes connected by a central isthmus. The thyroid produces essential hormones such as thyroxine (T4) and triiodothyronine (T3), which regulate the body’s metabolism, growth, and development. Because of its location and critical endocrine function, it is the gland most associated with the anterior neck region.

Why the Other Options Are Incorrect:

A. Pancreas

The pancreas is located in the abdominal cavity, specifically in the upper abdomen behind the stomach. It functions as both an endocrine gland (producing insulin and glucagon) and an exocrine gland (producing digestive enzymes), but it is not in the neck region.

B. Pituitary gland

The pituitary gland is located at the base of the brain, seated in the sella turcica of the sphenoid bone, directly beneath the hypothalamus. Though it is a crucial endocrine gland often called the "master gland," it is not located in the neck.

D. Thymus

The thymus is located in the upper anterior part of the chest (mediastinum), just behind the sternum and in front of the heart. It plays a major role in the development of the immune system, particularly in children, but it is not situated in the neck, and it lies inferior to the thyroid.

Correct Answer: B. Hypothyroidism

Explanation of the Correct Answer:

B. Hypothyroidism

Edna's symptoms — weight gain, cold intolerance, and low blood pressure — are classic indicators of hypothyroidism, a condition in which the thyroid gland produces insufficient thyroid hormones (primarily T3 and T4). These hormones are responsible for regulating metabolism, and when they are deficient, the metabolic rate slows down significantly. This results in unexplained weight gain, a reduced tolerance to cold temperatures due to slower metabolism and decreased heat production, and often low blood pressure due to reduced cardiac output and vascular resistance. Other common symptoms may include fatigue, dry skin, constipation, and depression.

Why the Other Options Are Incorrect:

A. Graves disease

Graves disease is an autoimmune disorder that causes hyperthyroidism, the opposite of hypothyroidism. It typically presents with weight loss despite increased appetite, heat intolerance, elevated blood pressure, rapid heart rate, and nervousness or anxiety — all of which are inconsistent with Edna’s symptoms.

C. Hyperthyroidism

Hyperthyroidism involves excessive production of thyroid hormones, leading to increased metabolic rate, weight loss, heat intolerance, and elevated blood pressure. This does not align with Edna’s symptoms of weight gain, cold intolerance, and low blood pressure.

D. Exophthalmos

Exophthalmos refers to bulging of the eyes, a symptom commonly associated with Graves disease. It is a clinical sign, not a disease or disorder in itself. Furthermore, Edna did not report eye symptoms such as bulging or irritation, so this does not match the systemic symptoms she described.

Correct Answer: A. Conservation of water.

Explanation of the Correct Answer:

The primary functions of the renal system (specifically the nephron) are to filter blood, remove waste, regulate electrolyte balance, and maintain homeostasis. One of the important functions of the kidneys is water conservation, especially in situations where the body needs to retain water to prevent dehydration.

The nephron, which is the functional unit of the kidney, plays a crucial role in reabsorbing water from the filtrate as it passes through different sections of the nephron (like the proximal convoluted tubule, loop of Henle, and distal convoluted tubule). This helps maintain the body's fluid balance and prevents excessive water loss through urine.

The kidneys also adjust the amount of water reabsorbed based on the body's hydration status. When the body is dehydrated, the kidneys conserve water, concentrating urine to retain as much fluid as possible.

Why the Other Options Are Incorrect:

B. Maintenance of normal body temperature:

This is not a primary function of the renal system. While the kidneys do play a role in regulating the balance of fluids, electrolytes, and waste removal, body temperature regulation is primarily controlled by the hypothalamus and mechanisms like sweating and shivering.

C. Maintenance of normal blood pressure:

While kidneys do help regulate blood pressure indirectly through mechanisms like the renin-angiotensin-aldosterone system (RAAS) and adjusting fluid volume, water conservation is more directly related to the kidneys' function. The kidneys influence blood pressure by regulating the volume of fluid in the body, but water conservation is a more specific function.

D. The afferent arteriole will vasoconstrict:

This is a physiological response that may occur under certain conditions, such as low blood pressure, but it is not a primary function of the renal system. The afferent arteriole can vasoconstrict to reduce blood flow into the glomerulus, which helps regulate GFR (glomerular filtration rate), but it is not a primary function related to water conservation.

Correct Answer:

A. Lung

Explanation:

Terminal bronchioles are the final branches of the conducting airway system before air reaches the respiratory zone (alveoli). They are found within the lungs, where they deliver air to the alveolar ducts and sacs for gas exchange.

Why Other Options are Wrong:

Heart

The heart is part of the cardiovascular system, not the respiratory tract. It has no bronchioles.

Femur

This is a long bone in the thigh, part of the skeletal system, and not related to respiratory anatomy.

Diaphysis

This refers to the shaft of a long bone. It’s also part of the skeletal system and unrelated to the lungs or bronchioles.

Correct Answer: A. Right arm

Explanation of the Correct Answer:

A. Right arm

The right lymphatic duct drains lymph from the right upper quadrant of the body, including the right arm, right side of the head and neck, and the right side of the chest. This duct ultimately empties into the right subclavian vein, where the lymph is reintroduced into the bloodstream.

Why the Other Options Are Incorrect:

B. Right leg

The right leg is not drained by the right lymphatic duct. Lymph from the right leg is collected by the thoracic duct, which drains lymph from the rest of the body, including the left side and the lower parts of the right side, like the right leg.

C. Left leg

The left leg is also drained by the thoracic duct, not the right lymphatic duct. The thoracic duct drains lymph from the left arm, left leg, and the left side of the chest, as well as the lower body (below the diaphragm) on both sides.

D. Left arm

The left arm is drained by the thoracic duct, which is the largest lymphatic vessel in the body and collects lymph from the left arm, the left side of the chest, and the lower body.

Correct Answer:

A. 28

Explanation:

The average menstrual cycle is typically 28 days long, though normal ranges can vary from 21 to 35 days. The cycle begins with the first day of menstruation and includes the follicular phase, ovulation (around day 14), and the luteal phase.

Why Other Options are Wrong:

30

While close to average, 30 is not the textbook value used in physiology; 28 is standard for calculation purposes.

45

This is abnormally long and could indicate hormonal imbalance or pathology.

14

This is the approximate time of ovulation, not the full cycle duration.

Correct Answer: D. Humoral stimulation

Explanation of the Correct Answer:

D. Humoral stimulation

Glucagon secretion is regulated through humoral stimulation, which refers to changes in the composition of the blood—particularly blood glucose levels. When blood glucose drops (hypoglycemia), the alpha cells of the pancreas detect this decrease and respond by secreting glucagon. Glucagon then stimulates the liver to break down glycogen into glucose (glycogenolysis) and to form new glucose (gluconeogenesis), both of which raise blood glucose levels. This process is a classic example of humoral regulation, where the chemical makeup of body fluids directly triggers hormone release.

Why the Other Options Are Incorrect:

A. Neural stimulation

Neural stimulation involves direct innervation by nerves, such as sympathetic stimulation triggering the adrenal medulla to release epinephrine. Glucagon release is not primarily triggered this way.

B. Hormonal stimulation

This involves one hormone triggering the release of another, like ACTH stimulating cortisol release. Glucagon is not secreted in response to another hormone.

C. Neurohormonal stimulation

This refers to hormones released by neurons into the bloodstream (e.g., oxytocin from the posterior pituitary). Glucagon is secreted by endocrine cells, not neurosecretory cells.

Correct Answer: A. T lymphocytes

Explanation of the Correct Answer:

A. T lymphocytes

Thymosin and thymopoietin are hormones secreted by the thymus, an organ located in the upper chest behind the sternum. These hormones play a critical role in the maturation and differentiation of T lymphocytes (T cells), which are essential components of the adaptive immune system. Immature T cells originate in the bone marrow but migrate to the thymus, where thymic hormones help them develop the ability to recognize foreign antigens while avoiding attacks on the body's own tissues. This process is crucial for developing a functional and self-tolerant T-cell population.

Why the Other Options Are Incorrect:

B. B lymphocytes

B lymphocytes mature in the bone marrow, not the thymus, and their development is not regulated by thymosin or thymopoietin.

C. Alpha cells

Alpha cells are located in the pancreas and secrete glucagon. Their development is unrelated to thymic hormones.

D. Chief cells

Chief cells are found in the stomach and are responsible for secreting pepsinogen, a precursor to the digestive enzyme pepsin. They are not influenced by thymic hormones.

Correct Answer:

Biopsy

Explanation:

A biopsy involves the removal of a small piece of tissue from the body for microscopic examination. It is the standard procedure used when a growth, lesion, or abnormal tissue needs to be evaluated for disease, such as cancer or infection. In this scenario, a skin growth is being sampled for diagnosis, making biopsy the appropriate choice.

Why Other Options are Wrong:

PAP smear

A PAP smear is a screening test that collects cells from the cervix to detect cervical cancer or precancerous changes. It is not used for analyzing skin growths or lesions.

Autopsy

An autopsy is a post-mortem examination of a body to determine the cause of death or study disease processes. It is only performed after death and not applicable to living patients or skin samples.

Debridement

Debridement involves the medical removal of dead, damaged, or infected tissue to improve healing, commonly used in wound care. It does not involve taking samples for microscopic analysis of growths.