Which letter from the following image represents the white blood cell subtype that includes B and T cells?

A. It protects the lungs from overinflating: While protective reflexes (like the Hering-Breuer reflex) exist to prevent overinflation, this is primarily a function of the lungs and the medulla, not directly the hypothalamus.

B. It modifies the medulla oblongata's functions: The hypothalamus influences the medulla oblongata, which controls the basic rhythm and rate of breathing, allowing the body to adjust ventilation in response to emotional states, temperature changes, and other stimuli.

C. It maintains the basic rhythm of breathing: The basic rhythm of breathing is primarily generated by the medulla oblongata and pons, while the hypothalamus modulates these functions rather than maintaining them directly.

D. It monitors the respiration rate in sleep and awake states: While the hypothalamus does play a role in the sleep-wake cycle, the actual monitoring of respiration rate is managed by the respiratory centers in the brainstem (medulla and pons).

A. Urinary Bladder: The urinary bladder is composed of smooth muscle, including the detrusor muscle, which contracts to expel urine during urination. The detrusor muscle allows the bladder to stretch as it fills with urine and contract when it's time to empty.

B. Ureter: The ureters are muscular tubes that transport urine from the kidneys to the bladder but do not contain detrusor muscle. They have a different type of smooth muscle that aids in peristalsis.

C. Renal Artery: The renal artery is a blood vessel that supplies blood to the kidneys and does not contain muscle tissue like the detrusor muscle.

D. Kidney: The kidneys are organs that filter blood to produce urine but do not contain detrusor muscle. They consist mainly of nephron structures for filtration and reabsorption.