Physiology
Cardiovascular
Regarding the lymphatic system, which of the following statements is CORRECT:
Answer:
Normally, filtration of fluid out of the capillaries is slightly greater than absorption of fluid into the capillaries. Fluid filtered by the microcirculation (about 8 L per day) is returned to the circulation by the lymphatic system. Lymphatic capillaries drain into collecting lymphatics and then into larger lymphatic vessels, both containing smooth muscle and unidirectional valves. From here, lymph is propelled by smooth muscle constriction and compression of the vessels by body movements into afferent lymphatics and then the lymph nodes, where bacteria and other foreign materials are removed by phagocytes. Most fluid is reabsorbed here by capillaries, with the remainder returning via efferent lymphatics and the thoracic duct. The lymphatic system plays a major role in the body's immune defence and is also important for absorption and transport of fats.Lymphatic Capillaries
Physiology / Cardiovascular / Peripheral Vascular System
Last Updated: 28th February 2019
Normally, filtration of fluid out of the capillaries is slightly greater than absorption of fluid into the capillaries. Fluid filtered by the microcirculation (about 8 L per day) is returned to the circulation by the lymphatic system.
Lymphatic capillaries are blind-ended tubes walled with endothelial cells which allow the entry of fluid, protein and bacteria, but prevent their exit. Lymphatic capillaries drain into collecting lymphatics and then into larger lymphatic vessels, both containing smooth muscle and unidirectional valves.
From here, lymph is propelled by smooth muscle constriction and compression of the vessels by body movements into afferent lymphatics and then the lymph nodes, where bacteria and other foreign materials are removed by phagocytes. Most fluid is reabsorbed here by capillaries, with the remainder returning via efferent lymphatics and the thoracic duct into the subclavian veins.
The lymphatic system plays a major role in the body's immune defence and is also important for absorption and transport of fats.
Lymphatic Capillaries. (Image by OpenStax College [CC BY 3.0 (https://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons)
Report A Problem
Is there something wrong with this question? Let us know and we’ll fix it as soon as possible.
Loading Form...
- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
