Since the Cardiovascular and Lymphatic Systems Are Not Directly Accessible

question 60

Multiple Choice

Since the cardiovascular and lymphatic systems are not directly accessible to microbes ________.

• A)it was initially believed that the systems lacked normal biota,however the Human Microbiome Project suggests that low levels of microbes may exist in the healthy state
• B)both systems are sterile in the healthy state
• C)the abundant microbiota enter via the gastrointestinal tract then cross the blood vessels
• D)the Human Microbiome Project confirmed that only pathogens exist in both systems

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Definitions:

Arachnoid Layer

A web-like middle layer of the meninges, which are protective coverings of the brain and spinal cord.

Pia Mater

Delicate membrane forming the inner covering of the brain and spinal cord.

Blood-brain Barrier

A protective barrier in the brain that controls the passage of substances from the bloodstream into the brain tissue.

Water-soluble Molecules

Compounds that can dissolve in water, typically involved in various biochemical processes in the body.