Anatomy & Physiology Flashcards

What is the primary function of the lymphatic system?

Answer: Maintain fluid balance and immunity.

The lymphatic system has two primary functions: it collects excess interstitial fluid and returns it to the bloodstream, thereby maintaining fluid balance in the body. Additionally, it plays a critical role in the immune system by producing and transporting immune cells, filtering pathogens, and initiating immune responses against foreign invaders.

Which structure filters lymph before it returns to the bloodstream?

Answer: Lymph node

Lymph nodes are small, bean-shaped organs located throughout the lymphatic system that act as filters for lymph. As lymph flows through the nodes, immune cells like lymphocytes and macrophages remove foreign particles, pathogens, and cellular debris before the fluid returns to the circulatory system. This filtration is crucial for immune surveillance and preventing the spread of infection.

What type of vessel carries lymph toward the heart?

Answer: Lymphatic vessels

Lymphatic vessels are specialized, one-way vessels that collect interstitial fluid and transport it as lymph towards the heart. Unlike arteries and veins which carry blood, lymphatic vessels are designed to return this filtered fluid to the bloodstream, preventing fluid accumulation in tissues. They contain valves to ensure unidirectional flow, aiding in lymph circulation.

Which organ plays a major role in filtering blood and supporting the immune system?

Answer: Spleen

The spleen is the largest lymphatic organ and plays a vital role in both filtering blood and supporting the immune system. It removes old or damaged red blood cells, stores platelets, and contains white blood cells that identify and destroy pathogens. It serves as a significant site for immune responses against blood-borne antigens.

What is the role of lymphatic capillaries?

Answer: Absorb interstitial fluid.

Lymphatic capillaries are tiny, blind-ended vessels that are highly permeable and designed to absorb excess interstitial fluid from the tissues. This fluid, once inside the lymphatic capillaries, is called lymph. Their unique structure allows them to collect proteins, cellular debris, and other substances that blood capillaries cannot easily reabsorb, initiating the lymphatic drainage process.

Where are the majority of immune cells activated within the lymphatic system?

Answer: Lymph nodes

Lymph nodes are critical sites for immune surveillance and the activation of immune cells. They are packed with lymphocytes (T cells and B cells) and macrophages, which encounter and respond to antigens brought in by the lymph. This is where immune responses are often initiated and amplified, leading to the proliferation of specific immune cells to combat infection.

Which type of muscle contraction helps move lymph through vessels?

Answer: Skeletal muscle

Unlike the cardiovascular system with its central pump (the heart), the lymphatic system relies on external forces to move lymph. Contractions of surrounding skeletal muscles, particularly during physical activity, compress the lymphatic vessels and propel lymph forward. Valves within the vessels prevent backflow, ensuring unidirectional movement towards the heart.

Which gland is important for T-cell maturation?

Answer: Thymus

The thymus is a primary lymphoid organ located in the chest, crucial for the maturation of T-lymphocytes (T-cells). Immature T-cells migrate from the bone marrow to the thymus, where they undergo a rigorous selection process to ensure they can recognize foreign antigens while tolerating the body's own cells. This maturation is essential for adaptive immunity.

What is the function of lymph?

Answer: Remove waste and transport immune cells.

Lymph is a fluid that circulates through the lymphatic system, performing several vital roles. It collects metabolic waste products, cellular debris, and excess fluid from tissues, returning them to the bloodstream for excretion. Additionally, lymph serves as a transport medium for immune cells, such as lymphocytes, enabling them to patrol the body and initiate immune responses against pathogens.