Urinary System — MCQs
Which of the following is NOT an anterior relation of the right kidney?
Injury to which of the following muscles that forms the deep support of the perineal body causes cystocele, enterocele and urethral descent?
Which of the following is not a posterior relation of the right kidney?
Tubuloglomerular feedback control is useful for which one of the following?
GFR is increased by all except?
Which of the following is present in males but not in females?
Ducts of Bellini are present in:
A diabetic patient presents with hyperkalemia and urinary pH < 5.5. What is the MOST likely underlying cause?
Biopsy of the exposed surface of the palatine tonsil reveals which type of tissue?
Which of the following does not form a visceral relation with the spleen?
Urinary System Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following is NOT an anterior relation of the right kidney?
- A. Hepatic flexure
- B. Liver
- C. 4th part of duodenum (Correct Answer)
- D. 2nd part of duodenum
Explanation: ***4th part of duodenum*** - The **4th part of the duodenum** is located to the **left of the vertebral column** and is related to the **left kidney**, not the right kidney. - This segment passes superiorly along the left side of the aorta to become continuous with the jejunum at the duodenojejunal flexure. *Liver* - The **right kidney's superior part** is in direct contact with the **right lobe of the liver**, often separated only by the peritoneum [1]. - This is a significant anterior relation, explaining why liver enlargement can sometimes displace the right kidney. *Hepatic flexure* - The **hepatic flexure** (right colic flexure) of the colon lies immediately inferior to the liver and anterior to the **lower part of the right kidney**. - This anatomical relationship means that the right kidney can be affected by diseases of the colon in this region. *2nd part of duodenum* - The **descending (2nd) part of the duodenum** lies anterior to the **hilum and medial part of the right kidney** [1]. - Its retroperitoneal position places it in close proximity to the renal structures, making it a key anterior relation.
Question 2: Injury to which of the following muscles that forms the deep support of the perineal body causes cystocele, enterocele and urethral descent?
- A. Sphincter of urethra and anus
- B. Pubococcygeus (Correct Answer)
- C. Bulbospongiosus
- D. Ischiocavernosus
Explanation: ***Pubococcygeus*** - The **pubococcygeus muscle** is a major component of the **levator ani muscle** group, forming the primary support structure of the pelvic floor [1]. Damage to this muscle impairs the support for the bladder, rectum, and uterus, leading to prolapse conditions like **cystocele**, **enterocele**, and **urethral descent**. - Its integrity is crucial for maintaining the position of pelvic organs and proper function of the urinary and defecatory systems, as it directly supports the vagina, rectum, and bladder neck [3]. *Sphincter of urethra and anus* - The **external urethral sphincter** primarily controls voluntary urination, and its injury mainly leads to **stress urinary incontinence**, not necessarily prolapse [2]. - The **external anal sphincter** controls defecation, and its injury would primarily lead to **fecal incontinence**, not cystocele, enterocele, or urethral descent [2]. *Bulbospongiosus* - The **bulbospongiosus muscle** is superficial, supporting the clitoris and compressing erectile tissue in females, and expelling semen/urine in males. - Its injury would primarily affect sexual function and perineal body integrity but is **not a primary cause of pelvic organ prolapse** like cystocele or enterocele [3]. *Ischiocavernosus* - The **ischiocavernosus muscle** is also superficial, maintaining erection of the clitoris/penis by compressing the crura. - Injury to this muscle would mainly disrupt **erectile function** and contribute minimally to pelvic organ support or prolapse.
Question 3: Which of the following is not a posterior relation of the right kidney?
- A. Subcostal nerve
- B. Diaphragm
- C. 11th rib (Correct Answer)
- D. Ilioinguinal nerve
Explanation: ***11th rib*** - The right kidney typically extends from the 12th thoracic vertebra to the 3rd lumbar vertebra, usually covered by the **12th rib**. - The **11th rib** is usually a posterior relation of the **left kidney**, due to the lower position of the right kidney compared to the left kidney. *Diaphragm* - The diaphragm lies **posterior** to both the right and left kidneys, separating them from the pleura and lungs. - This anatomical relationship means that renal procedures or severe kidney infections can sometimes affect the thoracic cavity. *Subcostal nerve* - The **subcostal nerve** (T12) runs inferior to the 12th rib and passes **posterior** to both kidneys. - It provides sensory innervation to the skin and motor innervation to abdominal muscles. *Ilioinguinal nerve* - The **ilioinguinal nerve** (L1) emerges from the lumbar plexus and travels **posterior** to the inferior pole of both kidneys [1]. - It primarily provides sensory innervation to the groin and parts of the external genitalia.
Question 4: Tubuloglomerular feedback control is useful for which one of the following?
- A. GFR (Correct Answer)
- B. Plasma sodium
- C. Plasma volume
- D. Determining tubular secretion
Explanation: ***GFR*** - **Tubuloglomerular feedback (TGF)** is a critical autoregulatory mechanism that maintains a relatively constant **glomerular filtration rate (GFR)** despite fluctuations in arterial blood pressure. - The **macula densa** cells at the end of the thick ascending limb of the loop of Henle sense the **volume** and **sodium chloride concentration** of the tubular fluid and release paracrine factors to adjust afferent arteriolar resistance. *Plasma sodium* - While TGF senses the **sodium chloride concentration** in the filtrate, its primary role is to regulate GFR, not directly control systemic plasma sodium levels. - Plasma sodium is primarily regulated by hormones like **ADH** and **aldosterone**, which influence water reabsorption and sodium excretion. *Plasma volume* - **Plasma volume** is regulated predominantly by hormonal mechanisms (e.g., **renin-angiotensin-aldosterone system**, **ADH**, **ANP**) and control over overall sodium and water balance, rather than by the acute, intrinsic GFR regulation of TGF. - Changes in plasma volume can indirectly affect GFR, but TGF is not the direct control mechanism for plasma volume itself. *Determining tubular secretion* - **Tubular secretion** is the process by which solutes are actively transported from the peritubular capillaries into the tubular lumen. - TGF influences **glomerular filtration**, not directly the rates of tubular secretion, which are regulated by specific transport proteins and physiological needs.
Question 5: GFR is increased by all except?
- A. Renal stone in ureter (Correct Answer)
- B. Efferent arteriole constriction
- C. Increased renal blood flow
- D. Decreased oncotic pressure
Explanation: ***Renal stone in ureter*** - A renal stone in the ureter causes **post-renal obstruction**, leading to a buildup of pressure in the Bowman's capsule, which in turn **reduces GFR**. - **Obstruction** impedes urine outflow, thereby increasing **hydrostatic pressure** in the tubular system and opposing filtration. *Efferent arteriole constriction* - **Constriction of the efferent arteriole** increases the **hydrostatic pressure** within the glomerulus, which promotes an increase in GFR. - This constriction retains blood in the glomerulus, thereby increasing the **filtration pressure**. *Increased renal blood flow* - An **increase in renal blood flow** elevates the **glomerular hydrostatic pressure** and increases the amount of plasma available for filtration, leading to an **increased GFR**. - A higher flow rate also helps to maintain a more constant **glomerular capillary oncotic pressure**, preventing early filtration equilibrium. *Decreased oncotic pressure* - **Decreased oncotic pressure** in the glomerular capillaries (e.g., due to hypoproteinemia) reduces the osmotic force opposing filtration. - This reduction in opposing force allows for a net increase in the **filtration pressure**, thereby **increasing GFR**.
Question 6: Which of the following is present in males but not in females?
- A. Bulbospongiosus muscle
- B. Membranous urethra
- C. Corpus cavernosum
- D. Bulbourethral gland (Correct Answer)
Explanation: ***Bulbourethral gland*** - Also known as **Cowper's glands**, these are exocrine glands found **exclusively in males**, with no homologous structure in females. - They are located inferior to the prostate gland within the deep perineal pouch, secreting pre-ejaculate fluid into the spongy urethra. - Females have Bartholin's glands (greater vestibular glands), which are functionally analogous but anatomically distinct structures. *Bulbospongiosus muscle* - This muscle is present in **both males and females**, though it has different functions. - In males, it covers the bulb of the penis and aids in penile erection and ejaculation. - In females, it covers the vestibular bulbs and supports the clitoris and vagina. *Membranous urethra* - While the male urethra is anatomically divided into prostatic, membranous, and spongy segments, the female urethra also passes through the urogenital diaphragm (perineal membrane), which some anatomists refer to as a "membranous" portion. - The key distinction is that the bulbourethral glands are **exclusively male structures** with no female equivalent, making them the most definitive answer. *Corpus cavernosum* - **Both males and females** possess homologous erectile tissue. - In males, paired corpora cavernosa form the bulk of the penile shaft. - In females, homologous erectile tissue forms the body of the clitoris.
Question 7: Ducts of Bellini are present in:
- A. Pancreas
- B. Liver
- C. Kidney (Correct Answer)
- D. Salivary gland
Explanation: ***Kidney*** - The Ducts of Bellini, also known as **large papillary collecting ducts**, are the terminal portions of the collecting duct system in the kidney. - They are located in the **renal medulla**, particularly within the renal papillae, and drain urine into the minor calyces. *Pancreas* - The pancreas is involved in **digestion** and hormone production (e.g., insulin), not urine formation. - Its duct system includes the **main pancreatic duct (Wirsung's duct)** and accessory pancreatic duct. *Liver* - The liver's primary functions are **metabolism**, detoxification, and bile production. Its duct system consists of **bile ducts**, which transport bile, not urine [1], [2]. - Its duct system consists of **bile ducts**, which transport bile, not urine. *Salivary gland* - Salivary glands produce **saliva** and have their own unique duct systems (e.g., Wharton's duct, Stensen's duct). - These glands are part of the digestive system and are not involved in renal function.
Question 8: A diabetic patient presents with hyperkalemia and urinary pH < 5.5. What is the MOST likely underlying cause?
- A. Uremia
- B. Primary hyperaldosteronism
- C. Type IV RTA (Correct Answer)
- D. Type I Renal tubular acidosis
Explanation: ***Type IV RTA*** - Patients with **diabetes mellitus** frequently develop **hyporeninemic hypoaldosteronism**, leading to Type IV RTA [1]. - This condition is characterized by **hyperkalemia** and **acidosis** with a paradoxically low urinary pH (typically < 5.5). *Uremia* - **Uremia** can cause hyperkalemia and acidosis, but it is a broader term for severe kidney failure and not the most specific underlying cause for the given urinary findings. - While patients with uremia can have aciduria, the combination of **diabetic hyperkalemia** and acid urine points more directly to a specific tubular defect. *Primary hyperaldosteronism* - **Primary hyperaldosteronism** is characterized by **hypertension**, **hypokalemia**, and metabolic alkalosis, which is the opposite of the patient's presentation [1]. - This condition involves excessive aldosterone production, leading to increased potassium excretion [1]. *Type I Renal tubular acidosis* - **Type I RTA** (distal RTA) is characterized by the inability to acidify urine, resulting in a **urinary pH > 5.5** despite systemic acidosis [1]. - While it can cause hypokalemia (due to increased distal K+ secretion) and acidosis, the elevated urinary pH is a key differentiating factor from this patient's presentation [1].
Question 9: Biopsy of the exposed surface of the palatine tonsil reveals which type of tissue?
- A. Stratified squamous epithelium (Correct Answer)
- B. Simple squamous epithelium
- C. Simple columnar epithelium
- D. Pseudostratified columnar ciliated epithelium
Explanation: The palatine tonsils are part of the **oropharynx**, which is subjected to mechanical abrasion from food and drink. **Stratified squamous epithelium** provides robust protection against such friction and is characteristic of surfaces needing high wear resistance. *Simple squamous epithelium* - This type of epithelium is found in areas where **diffusion** or **filtration** is important, such as the lining of blood vessels (endothelium) and alveoli of the lungs. - It would not provide adequate protection for the exposed surface of the tonsil that is subject to frequent mechanical stress. *Simple columnar epithelium* - Characterized by cells taller than they are wide, often found in the **gastrointestinal tract** for absorption and secretion. - It lacks the multi-layered structure needed for protection against the abrasive forces typical in the oropharynx. *Pseudostratified columnar ciliated epithelium* - This epithelium is primarily found in the **respiratory tract**, where its cilia help move mucus and trapped particles. - While it offers some protection, its primary function is not mechanical resistance, and it is not found on the exposed surfaces of the palatine tonsils.
Question 10: Which of the following does not form a visceral relation with the spleen?
- A. Stomach
- B. Splenic flexure of colon
- C. Left kidney
- D. Adrenal glands (Correct Answer)
Explanation: The adrenal glands, specifically the **left adrenal gland**, are located superior to the **left kidney** but are generally not in direct visceral relation with the spleen itself [2]. The spleen's concavities accommodate other organs. The spleen is typically located in the **left hypochondrium**, nestled against the diaphragm, superior to the left kidney, but the adrenal gland is usually separated by the kidney or surrounding fascia. *Stomach* - The **gastric impression** on the spleen's anterior surface is formed by the fundus of the **stomach**, indicating a direct visceral relation [3]. - The stomach is one of the primary organs that directly abuts the spleen's visceral surface. *Splenic flexure of colon* - The **colic impression** on the inferior aspect of the spleen is formed by the **splenic flexure of the colon**, confirming a direct visceral relation [1]. - This anatomical arrangement explains why an enlarged spleen can sometimes be palpated near the colon. *Left kidney* - The **renal impression** on the posterior aspect of the spleen is formed by the anterior superior surface of the **left kidney**, establishing a clear visceral relation [1]. - The spleen lies directly superior and lateral to the left kidney.
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