CLT Anatomy & Physiology for Laser Therapy 3 — Questions and Answers
Question 1: Which cellular organelle is considered the primary photoacceptor for low-level laser therapy at the mitochondrial level?
- Nucleus
- Ribosome
- Cytochrome c oxidase (Correct answer)
- Endoplasmic reticulum
Correct answer: Cytochrome c oxidase
Cytochrome c oxidase (Complex IV) in the mitochondrial respiratory chain absorbs red and near-infrared photons, initiating the photobiomodulation cascade.
Question 2: What is the approximate depth of the papillary dermis, which plays a role in superficial vascular laser treatments?
- 0.01–0.1 mm
- 0.1–0.3 mm (Correct answer)
- 1–2 mm
- 3–5 mm
Correct answer: 0.1–0.3 mm
The papillary dermis lies just beneath the epidermis at approximately 0.1–0.3 mm depth and contains the capillary loops targeted in vascular laser therapy.
Question 3: Which blood vessel type in the skin forms the primary target for laser treatment of port wine stains?
- Arterioles
- Venules
- Ectatic capillaries and postcapillary venules (Correct answer)
- Lymphatic vessels
Correct answer: Ectatic capillaries and postcapillary venules
Port wine stains consist of ectatic capillaries and postcapillary venules whose oxyhemoglobin selectively absorbs laser wavelengths around 577–585 nm.
Question 4: The stratum basale of the epidermis is significant in laser therapy because it contains:
- Dead keratinocytes only
- Melanocytes and basal keratinocytes undergoing mitosis (Correct answer)
- Sweat gland openings
- The thickest keratin layer
Correct answer: Melanocytes and basal keratinocytes undergoing mitosis
The stratum basale houses dividing keratinocytes and melanocytes, making it a critical layer to monitor for thermal damage during pigment-targeting laser procedures.
Question 5: Which physiological process describes ATP production stimulated by laser photobiomodulation?
- Glycolysis
- Oxidative phosphorylation enhancement via cytochrome c oxidase activation (Correct answer)
- Beta-oxidation
- Gluconeogenesis
Correct answer: Oxidative phosphorylation enhancement via cytochrome c oxidase activation
Laser light activates cytochrome c oxidase, boosting oxidative phosphorylation and ATP synthesis in the mitochondria of irradiated cells.
Question 6: In laser therapy for tendons, which structural protein is primarily being targeted for photobiomodulation-enhanced synthesis?
- Actin
- Myosin
- Type I collagen (Correct answer)
- Fibronectin
Correct answer: Type I collagen
Tendons are predominantly composed of Type I collagen, and laser photobiomodulation stimulates fibroblasts to increase Type I collagen synthesis for tendon repair.
Question 7: What is the role of nitric oxide (NO) in the physiological effects of laser therapy on blood vessels?
- It causes vasoconstriction to reduce bleeding
- It promotes vasodilation and increased local circulation (Correct answer)
- It stimulates melanin production
- It blocks nerve conduction permanently
Correct answer: It promotes vasodilation and increased local circulation
Laser therapy stimulates nitric oxide release from endothelial cells, causing vasodilation and improved microcirculation in treated tissues.
CLT Anatomy & Physiology for Laser Therapy 3
Which cellular organelle is considered the primary photoacceptor for low-level laser therapy at the mitochondrial level?