Lymphatic system Flashcards
1
Q
Lymphatic system functions
A
The lymphatic system moves fluid throughout the body and depends the body against disease-causing agents
- drains excess interstitial fluid
- transports dietary lipids (vitamin A, D, E, K)
- carries out immune responses
2
Q
Lymph vessels
A
Collect excess tissue fluid and return it to venous blood
- without a “drainage” system edema in tissues increases and high fluid pressure causes tissue damage or tissue death
- this is extravascular fluid
3
Q
Lymphatic system components
A
- lymphatic fluid - lymphatic vessels - lymph nodes - tonsils - thymus - spleen
4
Q
Lymph
A
Lymphatic fluid
- clear, watery-appearing fluid found in the lymphatic vessels
- closely resembles blood plasma in composition
5
Q
Interstitial fluid
A
IF
- complex fluid that fills the spaces between the cells and part of the extracellular matrix
- closely resembles blood plasma in composition
6
Q
Structure of lymphatic vessels
A
The capillary wall is formed by a single layer of thin, flat, endothelial cells — as the diameter increases from capillary size, the walls become thicker and have three layers
- lymphatic resemble veins in structure with these exceptions
1. Thinner walls
2. More valves
3. Lymph nodes
7
Q
Pics
A
Pic
8
Q
Lymphatic vessels function
A
Transportation of fluid, proteins, fats, and other substances to the general circulation
- do not form a closed circuit
- lymphatic capillaries begin blindly in intercellular space
9
Q
Lymphatic vessels
A
- lymphatic capillaries have greater permeability than blood capillaries
- large molecules are able to diffuse into lymphatic capillaries
- as lymph pressure increase, the cells of capillary walls overlap so that lymph does not move out
- lymphatic capillaries are attached to surrounding cells by connective tissue filaments
- as interstitial fluid increases, the tissue filaments are pulled and space between cells increases and fluid flows into capillary
10
Q
Lymphatic vessels 2
A
- virtually all capillary beds contain lymphatic capillaries
- lymphatic vessels follow the venous system
- lymphatic vessels of the viscera follow arteries
- lymphatic capillaries merge to form larger lymphatic and eventually form the main lymphatic trunks
11
Q
2 main ducts
A
- Right lymphatic duct
2. Thoracic duct (left lymphatic duct)
12
Q
Right lymphatic duct
A
Lymph from the RUQ -> right lymphatic duct -> right subclavian vein
13
Q
Thoracic duct
A
Lymph from the rest of the body -> thoracic duct -> left subclavian vein
14
Q
Pic
A
Pic
15
Q
Pic
A
Pic
16
Q
Lymphatic pump
A
There is no muscular pumping organ (heart) connected with the lymphatic vessels to force lymph from the lymph capillaries to the subclavian veins
- most of the lymphatic system has to overcome gravity
1. Respiration pumps: pressure changes in thoracic and abdominal cavities with respiration
2. Skeletal muscle pumps: “milking” action of muscle contractions. During exerise, lymph flow may increase as much as 10-15x
17
Q
Pic
A
Pic
18
Q
Structure of lymph nodes
A
Oval or bean shaped structures that are enclosed by a fibrous capsule
- afferent lymph vessels care lymph to node
- efferent lymph vessels carry lymph away from lymph node
19
Q
Location of lymph nodes
A
Most lymph nodes occur in groups, or clusters, in certain areas
- the group locations of the greatest clinical importance are as follows
1. Preauricular lymph nodes
2. Submental group and submandibular group
3. Superficial cervical lymph nodes
4. Axillary lymph nodes
5. Superficial cubical (Supra trochlear) nodes
6. Iliac and inguinal lymph nodes
20
Q
Pic
A
Pic
21
Q
Pic
A
Pic
22
Q
Functions of lymph nodes
A
- Defense: filtration and phagocytosis
2. Hematopoiesis
23
Q
Defense functions
A
- if overwhelmed, lymph nodes can become infected or damaged
1. Mechanical filtration: physically stops particles from progressing further in the body
2. Biological filtration: biological activity of cells destroys and removes particles
3. Phagocytosis: cells remove microorganisms and other particles (biological filtration)
24
Q
Hematopoiesis
A
Lymphoid tissue of lymph nodes serves as the site of the final stages of maturation for some types of lymphocytes and monocytes that have migrated from the bone marrow
25
Tonsils
- masses of lymphoid tissue like lymph nodes but without the afferent vessels
- located in a protective ring under the mucous membranes in the mouth and back of the throat
1. Palatine tonsils: on each side of the throat
2. Pharyngeal tonsil (adenoid): near posterior opening of nasal cavity
3. Lingual tonsils: near base of the tongue
26
Function of tonsils
- protect against bacteria that may invade tissue around the openings between the nasal and oral cavities
- the tonsils serve as the first line of defense form the exterior and as such are subject to chronic infection, or tonsillitis
27
Thymus
A primary organ of the lymphatic system along with red bone marrow
- located in the mediastinum
28
Function of thymus
Plays a critical role in the body’s defenses against infections
1. Source of lymphocytes before birth
2. Shortly after birth, thymus secretes thymosin and other regulators, which enables lymphocytes to develop into mature T cells
29
Spleen
Located directly inferior to the diaphragm, superior to most of the left kidney and posterior to the stomach
- roughly an ovoid shape and enclosed in a fibrous capsule
1. White pulp: dense masses of developing lymphocytes
2. Red pulp: near outer regions, made up of a network of fine reticular fibers submerged in blood
30
4 functions of spleen
1. Defense
2. Hematopoiesis
3. Red blood cell and platelet destruction
4. Blood reservoir
31
Spleen defense
As blood passes through the spleen, macrophages lining the sinusoids of the spleen remove microorganisms and destroy them
32
Spleen hematopoiesis
Monocytes and lymphocytes complete their development and become active in the spleen
33
Spleen red blood cell and platelet destruction
- macrophages in the lining of the spleen remove worn out red blood cells and imperfect platelets from the blood and destroy them
- macrophages also break apart hemoglobin molecules and salvage their iron and globin by returning them to the bloodstream for storage in bone marrow and liver
34
Spleen blood reservoir
At any given point in time the pulp of the spleen contains a considerable amount of blood
35
Splenectomy
- significant internal bleeding could occur if the spleen is accidentally ruptured
- surgical repair or removal of the spleen can stop the blood loss and save a life
36
Lymphatic drainage of the breast
- breast cancer is one of the most commion forms of malignancy in women
- 1/8 women will develop breast cancer in their lifetime
- an understanding of the lymphatic drainage is important in the diagnosis and treatment of this type of malignancy
- cancerous cells from the primary tumor can spread via the lymphatic system
- breast is drained by two sets of lymphatic vessels:
1. Lymphatic that drain the skin over the breast with the exception of areola and nipple
2. Lymphatic that drain the underlying substance of breast, as well as skin of areola and nipple
37
Breast lymph nodes
- more than 85% of the lymph from the breast enters the lymph nodes of the axillary region
- just as the lymphatic system collects foreign invaders like bacteria and viruses, this same system can transport (via lymphatic vessels) and collect (in lymph nodes) cancer cells
38
The lymphatic system and the whole body
- lymphatic system drains away excess water from large areas
- lymph is conducted through lymphatic vessels to nodes, wher contaminants are removed
- lymphatic system benefits the whole body by maintaining fluid balance and promoting freedom from disease
