LECTURE 4: LYMPHATICS

Question 2

What is Reticular Connective Tissue?

Answer 2

High cellular density tissue with a large number of collagen fibers.

Question 3

What is the Lymphatic System?

Answer 3

Complimentary to Cardiovascular System (CVS).

Question 4

What are the four key elements of the Lymphatic System?

Answer 4

Lymph, Lymph Vessels, Lymphatic Organs, Red Bone Marrow.

Question 5

What are the functions of the Lymphatic System?

Answer 5

Fluid Balance: Drains excess interstitial fluid.
Fat Absorption: Transports lipids and lipid-soluble vitamins (e.g., A, D, E, & K).
Immune Responses: White blood cells.

Question 6

What is Lymph?

Answer 6

Clear-white fluid similar to blood plasma.

Question 7

What are the components of Lymph?

Answer 7

Water, Lymphocytes, Cellular debris, Plasma proteins, Other cells.

Question 8

How does Lymph circulation help the body?

Answer 8

Helps balance blood volume by returning excess interstitial fluid to the bloodstream.

Question 9

What is the pathway of Lymph circulation?

Answer 9

1. Lymphatic Capillaries
2. Lymph Vessels & Nodes
3. Lymph Trunks
4. Lymph Ducts.

Question 10

What is Edema?

Answer 10

Swelling: Local or diffuse. Occurs when filtration > reabsorption.

Question 11

What is Lymphedema?

Answer 11

Caused specifically by lymphatic dysfunction.

Question 12

What is Innate Immunity?

Answer 12

The defense system one is born with. Non-specific to pathogens. No memory component.

Question 13

What are the first lines of defense in Innate Immunity?

Answer 13

Physical barriers (e.g., skin, mucosa) and physiological responses (e.g., fever, inflammation).

Question 14

What is Acquired Immunity?

Answer 14

Specific to certain pathogens. Has a memory function.

Question 15

What are the types of Lymphocytes involved in Acquired Immunity?

Answer 15

T-cells and B-cells, including Memory cells.

Question 16

What is Humoral Immunity?

Answer 16

Works via antibodies. B-cells become plasma cells, producing antibodies.

Question 17

What is Cellular Immunity?

Answer 17

Works via cells (specifically T-cells). T-helper cells detect antigens and signal to other cells.

Question 18

What is an Antigen?

Answer 18

A foreign substance that triggers an immune response.

Question 19

What is an Antigen-Presenting Cell?

Answer 19

Engulfs the antigen and presents fragments to T-cells.

Question 20

What are the types of T-cells in Cellular Immunity?

Answer 20

T-helper cells, T-cytotoxic cells (produce T-memory cells), T-regulatory cells (help regulate the immune response).

Question 21

What is HIV?

Answer 21

Human Immunodeficiency Virus: A retrovirus that attacks T-helper cells.

Question 22

What is AIDS?

Answer 22

Acquired Immunodeficiency Syndrome: T-helper cell count <200 cells/ml, results in opportunistic infections (OIs).

Question 23

Which type of cell directly produces antibodies?

Answer 23

A: B-cells
B: Plasma cells
C: T-cytotoxic cells
D: T-helper cells
E: T-regulatory cells.

Question 24

What are the Primary Lymphatic Organs?

Answer 24

Red Bone Marrow and Thymus.

Question 25

What are the Secondary Lymphatic Organs & Tissues?

Answer 25

Lymph Nodes, Lymph Nodules (MALT, Waldeyer’s Ring), Spleen.

Question 26

What does Red Bone Marrow produce?

Answer 26

Myeloid Stem Cells (Erythrocytes, Thrombocytes, Granular Leukocytes, Monocytes & Macrophages) and Lymphoid Stem Cells (T-cells, NK cells, B-cells).

Question 27

Where is Red Bone Marrow located?

Answer 27

In flat bones (e.g., axial skeleton) and ends of long bones (e.g., appendicular skeleton).

Question 28

What is the structure of the Thymus?

Answer 28

Bilobed, capsulated with trabeculae (lobules) and stroma (thymic epithelial cells).

Question 29

What occurs in the Cortex of the Thymus?

Answer 29

Contains thymocytes, dendritic cells, macrophages. Positive selection ensures appropriate T-cell response; negative selection prevents autoimmunity.

Question 30

What occurs in the Medulla of the Thymus?

Answer 30

Contains mature T-cells, more dendritic cells, macrophages. T-cell release occurs here.

Question 31

What are Lymph Nodes?

Answer 31

Bean-shaped structures along lymph vessels, often clustered.

Question 32

What is the flow of Lymph through Lymph Nodes?

Answer 32

Afferent vessels → Sinuses → Efferent vessels → Lymph trunks.

Question 33

What are Lymphatic Nodules?

Answer 33

Acapsular and aggregated.

Question 34

What is MALT?

Answer 34

Mucosa-Associated Lymphoid Tissue, includes diffuse and organized structures like Peyer’s Patches and Waldeyer’s Ring.

Question 35

What is the Spleen?

Answer 35

Largest mass of lymphoid tissue located in the left upper abdomen.

Question 36

What are the functions of the Spleen?

Answer 36

Immunological role: Responds to pathogens in blood. Non-immunological role: Storage of platelets, iron, and RBCs.

Question 37

What is Tonsillitis?

Answer 37

Inflammation of the Tonsils (usually palatine tonsils).

Question 38

What causes Tonsillitis?

Answer 38

Often viral, but can also be caused by group A Streptococcus.

Question 39

What are the signs of Infection in Lymph Nodes?

Answer 39

Lymphadenopathy: Disease of lymph nodes with abnormal size or consistency. Can be generalized or localized.

Question 40

What is Lymphadenitis?

Answer 40

Enlarged, painful, inflamed lymph nodes.

Question 41

What are Lymphomas?

Answer 41

Cancer of the lymph nodes.

Question 42

What is Metastasis?

Answer 42

Spread of disease through lymphatic vessels, hematogenously, or transcoelomically.

Question 43

What are the types of Metastasis?

Answer 43

Transcoelomic: Spread through body cavities. Hematogenous: Spread via blood vessels. Lymphogenous: Spread via lymphatic vessels.

Question 44

Where do T-cells mature?

Answer 44

A: Lymph nodes B: Lymph nodules C: Red bone marrow D: Spleen E: Thymus.

Question 45

What are the principal groups of Lymph Nodes, Trunks, and Ducts?

Answer 45

Regions: Head & Neck, Thorax, Upper Limb & Axilla, Abdomen & Pelvis, Viscera, Lower Limb.

Question 46

What are the Lymphatic Ducts formed by?

Answer 46

3 trunks: Jugular, Subclavian, Bronchomediastinal.

Question 47

What is the Lymphatic Drainage by Region for the Head & Neck?

Answer 47

Includes Deep Cervical Nodes, Waldeyer’s Ring, Supraclavicular Nodes.

Question 48

What is the function of the Spleen?

Answer 48

Immunological role: Responds to pathogens in blood. Non-immunological role: Storage of platelets, iron, and RBCs.

Question 49

What are the final notes on the Lymphatic System?

Answer 49

The lymphatic system functions in maintaining fluid balance, immunity, and nutrient absorption.