The Antigen Receptor on a T Cell Recognizes a Degraded

question 14

Multiple Choice

The antigen receptor on a T cell recognizes a degraded fragment of a protein (i.e., a peptide) bound to a specialized cell surface peptide-binding receptor called an MHC molecule. One key aspect of this system is that the peptides displayed on MHC molecules can be derived from intracellular proteins. This mode of antigen recognition is particularly important in allowing the adaptive immune response to detect infections by:

• A) Large helminthic parasites in the gastrointestinal tract
• B) Intracellular pathogens, such as viruses and some protozoa
• C) Extracellular bacteria that colonize the lungs
• D) Fungi that form hyphae in the bronchial airways
• E) Fungal infections in the skin epithelium

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Definitions:

Unencapsulated Receptors

Sensory receptors not surrounded by connective tissue capsules, detecting changes in their environment.

Meissner's Corpuscles

Sensitive mechanoreceptors located in the papillary layer of the dermis, particularly in areas like the fingertips and lips, responsible for sensitivity to light touch.

Free Nerve Endings

Sensory receptors found throughout most of the body that respond to pain, temperature, touch, and pressure.

Nociceptors

Specialized sensory neurons that detect signals indicating potential harm and transmit pain signals to the brain.