| Question | Answer |
| The lymphatic system | - Protects us against disease
- Lymphatic system cells respond to:
- Environmental Pathogens ( e.g bacteria, viruses, fungi, parasites)
- Toxins
- Abnormal body cells, such as cancers |
| Functions | - Drainage of interstitial fluid
- Transporting dietary lipids and lipid soluble vitamins (A,D,E an K)
- facilitation of the immune response (i.e production, maintenance and distribution of lymphocytes) |
| Function of the lymphatic system | To produce, maintain, and distribute lymphocytes |
| What is the function of lymphocytes? | - Detects problems
- Travel into site of inquiry or infection |
| Where are lymphocytes found? | - lymphocytes are found
- In lymphoid tissues (e.g, tonsils)
- Lymphoid organs (e.g, spleen, thymus)
- In red bone marrow |
| What are the 3 types of Lymphocytes? | - T cell: Thymus-dependent
- B cell: Bone marrow-derived
- NK cells: Natural killer cells |
| Lymphocyte Circulation | From blood to interstitial fluid through capillaries returns to venous blood through lymphatic vessels |
| The circulation of fluids | From blood plasma to lymph and back to the nervous system, transports hormones, nutrients, and waste product |
| What is a Lymphatic vessel? | - Are the vessels that carry lymph
- Lymphatic systems begins with the smallest vessels
- lymphatic capillaries (terminal lymphatics) |
| What is immunity? | The ability to resist infection and disease |
| What tells and tissues are involved in the production of immunity? | All cells and tissues are involved in production of immunity, not just the lymphatic ones |
| What are nonspecific defences? | Block or attack any potential infectious organisms, cannot distinguish one attack from other |
| what are the seven major categories of innate (nonspecific) immunity? | 1. physical barrier
2. Phagocytes
3. Immune surveillance
4. Interferons
5. Complement
6. Inflammatory response
7. Fever |
| What are specific defences? | - Lymphocytes
- Part of the immune response
- Identify, attack, and develop immunity to a specific pathogen |
| What are the organisations of the lymphatic system? | Lymph
- fluid similar to plasma, does not have plasma proteins
Lymphatic vessels
- Carry lymph from peripheral tissue to the venous system
Lymphoid tissues & organs
Lymphocytes, phagocytes, and other immune systems cells |
| What are lymphatic capillaries? | Lymphatic capillaries serve to drain and process extra-cellular fluid. |
| Lymphatic capillary structure | Endothelial cells loosely bound together with over lap. This structure helps to let fluid in, but not out. |
| How do lymphatic capillaries work? | The overlap acts as one-way valve
- Allows fluid, solute, viruses, and bacteria to enter
- Prevents return to intercellular space |
| What is the fluid inside lymphatic capillaries called? | Lymph |
| What are Lacteals? | Are special lymphatic capillaries in small intestine. They transport lipids from digestive tract |
| In what ways to lymphatic capillaries differ from blood capillaries? | 1. Start as pockets rather than dudes
2. Have larger diameters
3. Have thinner walls
4. Flat or irregular outline in sectional view |
| What is the circulation of the lymphatic system? | Blood plasma (from capillaries) —> Interstitial/tissue fluid —> Lymphatic capillary —> Lymph vessels, trunks & ducts —> Blood plasma ( vein at base of neck) |
| What is the structures of lymph vessels? | -Thin walls
- Resemble veins; have more valves
- Have Lymph nodes at intervals
- Respiratory & muscular pumps promote flow of lymph towards large veins/heart |
| What are the 2 types of lymphatic vessels and what is the difference? | 1. Superficial lympahtics
2. The deep lymphatics
- Are the larger vessels that accompany deep arteries and veins |
| Where are lymphatic vessels located? | - Skin
- Mucous membranes
- Serous membranes lining body cavities |
| What are the primary lymphatic organs? | -Red bone marrow
- Thymus |
| What are the secondary lymphatic organs? | - Spleen
- Lymph nodes
- Appendix |
| What are the diffuse lymphatic tissue? | Tonsils, adenoids & Peyer’s patches |
| What is the Thymus Gland? | -Found in the mediastinum above the heart
- Large in infancy and atrophies but functional in adulthood
- Thymus makes thymosin hormones for development and maturation of T cells
- T cells mature here |
| What are lymph nodes? | - Lymph nodes are surrounded by a connective tissue capsule
- Each compartment or lobule is made up of a framework of reticular cell (reticulocytes)
- Reticular cells phagocytise unwanted substances
- B Lymphocytes produce antibodies
- Filter Lymph |
| What is a spleen? | - Found left side of abdominal cavity below the diaphragm
- Red pulp - removes worn out platelets, RBC and stores platelets
- Produces RBC in the foetus
- White pulp - immune function removes blood borne pathogens |
| What does MALT stand for? | mucosa-associated lymphoid tissues |
| What are tonsils? | - Surround the opening to the respiratory and digestive tracts
Five tonsils
2 palatine (either side of the oral cavity), 2 lingual (at the base of the tongue,)1 pharyngeal or adenoid (on the posterior wall of the nasopharynx)
- Tonsils filter air |
