A patient is recovering from a bone fracture. Which dietary component is crucial for promoting bone healing during this time?

A. Enteric nervous system:The Enteric nervous system is a mesh-like system of neurons that governs the function of the gastrointestinal tract (the "brain of the gut"). It manages digestion, not the systemic stress response.

B. Central nervous system:While the brain (specifically the hypothalamus and amygdala) perceives the threat, the execution of the physiological "fight or flight" changes (racing heart, dilated pupils) is carried out by the autonomic nerves.

C. Peripheral nervous system:Similar to Question 45, this is a broad anatomical term. While the stress response nerves are located in the periphery, the specific functional system is the Autonomic Nervous System.

D. Autonomic nervous system:The Autonomic Nervous System has two main branches: the Sympatheticand the Parasympathetic. The Sympathetic division is directly responsible for the "fight or flight" response, mobilizing the body's energy during stress.

Question: 47 of 48

A middle-aged woman has been diagnosed with a vitamin D deficiency. How does this deficiency affect her musculoskeletal system?

1. Reduced calcium absorption leading to weak bones
2. Increased muscle mass
3. Enhanced collagen production
4. Hypercalcemia due to excess calcium

Correct answer: A

A. Reduced calcium absorption leading to weak bones:The primary physiological role of Vitamin D is to facilitate the absorption of calciumin the intestines. Without sufficient Vitamin D, the body cannot absorb enough calcium from the diet. To maintain blood calcium levels, the body will then leech calcium from the bones, leading to lower bone density (osteopenia/osteoporosis) and increased fracture risk.

B. Increased muscle mass:Vitamin D deficiency is actually associated with muscle weakness and pain (proximal myopathy), not an increase in muscle mass.

C. Enhanced collagen production:Vitamin D is not a primary driver of collagen synthesis; Vitamin C is the key nutrient for collagen production.

D. Hypercalcemia due to excess calcium:A deficiency in Vitamin D leads to hypocalcemia(low calcium levels) because the gut cannot absorb it efficiently. Hypercalcemia would be a sign of Vitamin D toxicity (overdose) or hyperparathyroidism.

A. Bladder control:Voluntary bladder and bowel control is mediated by the sacral nerves (S2-S4). A C5 injury severs the connection between the brain and the lower spinal cord, typically resulting in neurogenic bladder (loss of voluntary control).

B. Full hand dexterity:The nerves controlling the hands and fingers originate from the C8 and T1 levels. A C5 injury usually leaves the patient with shoulder and partial biceps control, but paralysis of the wrists and hands.

C. Ability to breathe independently:The diaphragm is innervated by the phrenic nerve, which originates from spinal roots C3, C4, and C5("C3, 4, 5 keep the diaphragm alive"). While a C5 injury may weaken respiratory effort (due to loss of intercostal muscles), the diaphragm usually remains functional, allowing independent breathing.

D. Ability to walk unaided:The muscles for walking are controlled by the lumbar and sacral spinal nerves. A cervical injury (C5) results in quadriplegia (tetraplegia), involving paralysis of both the trunk and legs.