Special Senses?

Question 1

What part of vestibular apparatus detect linear accerlaration and angular acceleration?

Answer 1

Linear acceleration:

otolith organs
Utricle + saccule

Angular acceleration
3 semicircular canals

Question 2

Explain the detection of linear head acceleration?

Answer 2

Linear acceleration is detected by the otolithic organs, which are two structures located within the vestibular apparatus of the inner ear: the utricle and the saccule.

1. Utricle: The utricle is larger and located horizontally within the vestibular apparatus. It detects linear acceleration in the horizontal plane, such as forward and backward movements or side-to-side movements.
2. Saccule: The saccule is smaller and located vertically within the vestibular apparatus. It detects linear acceleration in the vertical plane, such as up-and-down movements or changes in head position with respect to gravity.

Both the utricle and the saccule contain sensory structures called otolithic organs. These organs consist of hair cells embedded in a gelatinous mass containing tiny calcium carbonate crystals called otoliths (or otoconia). When the head moves linearly, the otoliths shift due to inertia, which bends the hair cells and stimulates them. This stimulation generates signals that are transmitted to the brain via the vestibulocochlear nerve (cranial nerve VIII), providing information about the direction and magnitude of linear acceleration.

Question 3

What is shaken baby syndrome? Its symptoms?

Answer 3

Shaken baby syndrome (SBS), also known as abusive head trauma, is a serious form of child abuse that occurs when an infant or young child is forcefully shaken, causing rapid back-and-forth movement of the head. This violent shaking can result in severe and often life-threatening injuries to the baby’s brain and may also cause damage to the neck, spine, and other parts of the body.

The rapid acceleration and deceleration of the head during shaking can lead to several types of injuries, including:

1. Brain Injury: The brain may impact against the skull, causing bruising, bleeding (subdural hematoma), swelling, and tearing of blood vessels and nerve fibers. These injuries can result in permanent brain damage, cognitive impairment, developmental delays, and neurological deficits.
2. Retinal Hemorrhage: The forceful shaking can cause bleeding in the retina of the eyes, leading to retinal hemorrhage. This can result in vision loss or blindness and is considered a hallmark sign of shaken baby syndrome.
3. Cervical Spine Injury: The violent shaking can also cause damage to the cervical spine (neck), resulting in fractures, dislocations, or spinal cord injury.
4. Other Injuries: In addition to brain and retinal injuries, shaken baby syndrome may cause other injuries such as rib fractures, bruises, and soft tissue injuries.