The lymphatic system is a vital part of the immune and circulatory systems. It consists of lymph vessels, which transport lymph fluid throughout the body, maintaining fluid balance and aiding in the removal of waste. Lymph circulation occurs through a network of vessels, nodes, and ducts, with lymph moving in one direction—toward the heart. Key lymphatic tissues include the spleen, which filters blood and supports immune function, and the thymus, where T-lymphocytes mature. Together, these structures help defend the body against infections and maintain overall immune health.
Lymphatic System - Structure and function of lymph vessels, lymph circulation and lymphatic tissues –spleen and thymus
Time: 15:00
What is the primary function of the overlapping endothelial cells that form the walls of lymphatic capillaries (minivalves)?
[a] To propel lymph forward using muscular contraction
[b] To allow interstitial fluid to enter but not exit the capillary
[c] To actively filter pathogens out of the fluid
[d] To produce and secrete lymph fluid
The white pulp of the spleen is primarily involved in which function?
[a] Storing platelets and monocytes
[b] Removing old and damaged red blood cells
[c] Immune surveillance and response, containing mostly lymphocytes
[d] Producing red blood cells in the fetus
The thymus gland is most active and largest during which period of life?
[a] Childhood and adolescence
[b] Adulthood (ages 30-50)
[c] Old age (70+)
[d] In utero (before birth)
Which major lymphatic duct is responsible for draining lymph from the right arm, right side of the head, and right thorax?
[a] Thoracic duct
[b] Lumbar duct
[c] Right lymphatic duct
[d] Jugular trunk
The primary, crucial function of the thymus gland is:
[a] Filtering lymph to remove pathogens
[b] Serving as the site of B-cell activation
[c] Acting as a reservoir for blood
[d] Serving as the maturation site for T-lymphocytes
Which of the following mechanisms is NOT involved in propelling lymph through the lymphatic vessels?
[a] The skeletal muscle pump
[b] Pumping action of the heart ventricles
[c] Pressure changes in the thorax during breathing
[d] Contractions of smooth muscle in the vessel walls
The red pulp of the spleen is chiefly concerned with:
[a] Maturation of T-cells
[b] Mounting immune responses against bloodborne antigens
[c] Disposal of worn-out red blood cells and storage of platelets
[d] Absorption of dietary fats
Specialized lymphatic capillaries located in the small intestine that absorb digested fat are called:
[a] Cisterna chyli
[b] Lacteals
[c] Peyer's patches
[d] Crypts
Lymph from the lower body and the left side of the upper body ultimately drains into the venous circulation via the:
[a] Right lymphatic duct
[b] Azygos vein
[c] Thoracic duct
[d] Superior vena cava directly
What is the term for the age-related atrophy or shrinking of the thymus gland?
[a] Thymitis
[b] Hyperplasia
[c] Thymoma
[d] Involution
Structurally, lymphatic collecting vessels are most similar to which other type of vessel?
[a] Arteries
[b] Veins
[c] Capillaries
[d] Arterioles
Where is the spleen typically located in the human body?
[a] In the right upper quadrant, inferior to the liver
[b] In the lower neck, posterior to the sternum
[c] In the left upper quadrant, curling around the anterior aspect of the stomach
[d] In the pelvic cavity, near the bladder
Unlike lymph nodes, the spleen and thymus do not have what type of vessel?
[a] Efferent lymphatic vessels
[b] Afferent lymphatic vessels
[c] Arteries
[d] Veins
The fluid that is collected by the lymphatic system and returned to the bloodstream is known as:
[a] Plasma
[b] Serum
[c] Lymph
[d] Cytosol
A patient who has had a splenectomy (removal of the spleen) is at an increased risk for:
[a] Lymphedema in the lower extremities
[b] Sepsis from encapsulated bacteria
[c] Impaired fat absorption
[d] Autoimmune disorders
Which of the following correctly describes the direction of lymph flow?
[a] A two-way circuit from the heart to tissues and back
[b] From lymph nodes toward the capillaries
[c] A one-way system flowing from tissues toward the heart
[d] From the ducts to the collecting vessels
The thymus is considered part of the endocrine system because it secretes hormones, such as thymosin, which promote the development of:
[a] B-lymphocytes
[b] Plasma cells
[c] T-lymphocytes
[d] Red blood cells
Lymphedema is a condition characterized by:
[a] An overproduction of lymphocytes
[b] Localized fluid retention and tissue swelling due to a compromised lymphatic system
[c] Inflammation of the lymph nodes due to infection
[d] A cancerous growth within a lymphatic organ
The spleen's role as a "blood reservoir" is primarily due to its capacity to store:
[a] Lymph fluid
[b] Matured T-cells
[c] A large volume of red blood cells and platelets
[d] Calcium and other electrolytes
Where does the thoracic duct, the largest lymphatic vessel, begin?
[a] In the subclavian vein
[b] As a continuation of the right lymphatic duct
[c] As an enlarged sac called the cisterna chyli in the abdomen
[d] In the thymus gland
A unique feature of the thymus that distinguishes it from other lymphoid organs is that it:
[a] Is located in the thoracic cavity
[b] Contains lymphocytes
[c] Does not directly fight antigens; its primary role is maturation
[d] Has a cortex and a medulla
The main force that drives fluid from the interstitial spaces into the lymphatic capillaries is:
[a] Osmotic pressure of plasma proteins
[b] Hydrostatic pressure of the interstitial fluid
[c] Arterial blood pressure
[d] The pull of gravity
Which of the following functions is NOT attributed to the spleen?
[a] Immune surveillance of the blood
[b] Removal of aged erythrocytes
[c] Maturation of B-lymphocytes
[d] Storage of platelets and monocytes
Lymph is returned to the cardiovascular system at the junction of which two vessels?
[a] The superior and inferior vena cava
[b] The aorta and the pulmonary artery
[c] The internal jugular vein and the subclavian vein
[d] The hepatic portal vein and the splenic vein
The thymus is a bilobed organ located in the:
[a] Abdominal cavity, superior to the kidneys
[b] Anterior superior mediastinum, posterior to the sternum
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