10. Case Study Ten Quiz: Human Skeletal System, Inflammation, and Reflexes- Isla's Humerus Fracture

What type of fracture did Isla sustain?

A mid-shaft fracture of the humerus.

What is the location and classification of the humerus?

It is located in the upper limb of the appendicular skeleton and is classified as a long bone.

How is pain transmitted from Isla's broken humerus to her brain?

Nociceptors detect injury, sensory neurons carry the signal through spinal nerves to the dorsal root of the spinal cord, then to the thalamus and cerebral cortex for pain perception.

What physiological change occurs at the site of injury due to inflammation?

Swelling (Edema) occurs due to increased blood flow and fluid leakage, and tenderness and redness result from vasodilation and chemical signals sensitizing nerve endings.

What roles do osteoblasts and osteoclasts play in bone remodeling after a fracture?

Blasts Build new bone and repair the fractured area, while Clasts Chew (break down) old bone tissue to allow for proper healing.

What hormone raises blood calcium levels and what are its three actions?

Parathyroid hormone (PTH) raises blood calcium by stimulating bone resorption, increasing calcium reabsorption in the kidneys, and promoting the activation of Vitamin D.

Which muscle is responsible for flexion of the elbow?

Biceps brachii.

Which muscle is responsible for extension of the elbow?

Triceps brachii.

What is the first step in the reflex arc when Isla's skin was touched by the cast saw?

The stimulus is the cast saw touching the skin.

What is the role of the primary sensory neuron in the reflex arc?

It takes the 'danger' message to the spinal cord.

What is the function of the interneuron in the reflex arc?

It is stimulated by action potentials/neurotransmitters from the primary sensory neuron.

What does the primary motor neuron do in the reflex arc?

It is stimulated by the interneuron and activates muscles in the arm to move away from the stimulus.

What is the outcome of the reflex arc when Isla's arm reacts to the cast saw?

Isla's arm moves away from the cast saw.

What is edema and how does it relate to inflammation?

Edema is swelling caused by increased blood flow and fluid leakage into surrounding tissues during the inflammatory response.

What is the role of histamine and prostaglandins in injury response?

They sensitise nerve endings, making the area painful to touch.

How does PTH affect calcium levels in the kidneys?

It increases calcium reabsorption, reducing the amount lost in urine.

What is the significance of Vitamin D activation by PTH?

It enhances calcium absorption in the intestines.

What happens to the bone during the healing process after a fracture?

Remodeling occurs, involving both the building of new bone and the breakdown of damaged bone.

What is the primary function of the humerus in the arm?

To support weight and facilitate movement.

What are nociceptors and their role in pain perception?

They are sensory receptors that detect injury and transmit pain signals to the brain.

What is the significance of the cast for Isla's arm?

It immobilizes the arm to allow for proper healing of the fracture.