Spinal Muscular Atrophy | Mechanism & Presentation

The video explains spinal muscular atrophy (SMA), focusing on the progressive death of alpha motor neurons due to the deletion of the SMN gene. It describes the role of alpha motor neurons in muscle contraction and the consequences of their death, leading to muscle atrophy. The video compares SMA with other motor neuron diseases and peripheral nerve conditions, highlighting the lack of sensory changes in SMA. It also discusses the hereditary nature of SMA, its symptoms, and the different types based on onset age.

What is the primary function of an alpha motor neuron?

• To initiate voluntary muscle contraction

• To process visual information

• To regulate involuntary muscle movements

• To transmit sensory information to the brain

What happens to muscles if alpha motor neurons die?

• They become more sensitive

• They lose the ability to contract

• They become stronger

• They start to regenerate

What is the role of the SMN protein in alpha motor neurons?

• It repairs damaged neurons

• It enhances sensory perception

• It allows the neurons to survive

• It increases muscle strength

What is a key characteristic of spinal muscular atrophy progression?

• It causes immediate neuron death

• It progresses symmetrically

• It affects distal muscles first

• It primarily affects sensory neurons

How does spinal muscular atrophy differ from peripheral nerve diseases?

• It causes sensory changes

• It affects both motor and sensory neurons

• It only affects sensory neurons

• It only affects motor neurons

Which muscles are affected first in spinal muscular atrophy?

• Cardiac muscles

• Facial muscles

• Proximal muscles

• Distal muscles

What is the genetic cause of spinal muscular atrophy?

• Overproduction of SMN protein

• Duplication of the SMN gene

• Deletion of the SMN gene

• Mutation in the sensory neurons

Where is the SMN gene located?

• On the long arm of chromosome 5

• On the short arm of chromosome 7

• On the long arm of chromosome 7

• On the short arm of chromosome 5

Which type of spinal muscular atrophy has the best prognosis?

• Type 1

• Type 2

• Type 3

• Type 4

What type of pain is associated with spinal muscular atrophy?

• Neurological pain

• Musculoskeletal pain

• Cardiac pain

• Gastrointestinal pain