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Human physiology, hazards and health risks
Published in Stephen Battersby, Clay's Handbook of Environmental Health, 2023
Revati Phalkey, Naima Bradley, Alec Dobney, Virginia Murray, John O’Hagan, Mutahir Ahmad, Darren Addison, Tracy Gooding, Timothy W Gant, Emma L Marczylo, Caryn L Cox
The lymphatic system is a network of lymphatic vessels and lymph nodes found along these vessels, through which lymph, a fluid derived from interstitial fluid, flows. It constitutes a route by which interstitial fluid can reach the blood vessels or the cardiovascular system. This movement of interstitial fluid as lymph to the cardiovascular system is very important because the amount of fluid filtered out of all the blood vessel capillaries (except those of the kidney) exceeds that which is reabsorbed by approximately 4 litres each day. These 4 litres are returned to the blood via the lymphatic system. In the process, the small amount of protein that usually leaks out of the capillaries is also brought back into the circulation by the lymphatic system. The lymph node cells meet the foreign substances and start off the immune response via the lymph flowing through them. Each lymph node is a honeycomb of sinuses (enlargements or sac-like dilations containing lymph) lined by macrophages with large clusters of lymphocytes between the sinuses. The spleen is the largest of the organs containing lymphoid tissue which lies on the left side of the abdominal cavity between the stomach and the diaphragm.
Thermography by Specialty
Published in James Stewart Campbell, M. Nathaniel Mead, Human Medical Thermography, 2023
James Stewart Campbell, M. Nathaniel Mead
Obstruction or destruction of the lymphatic channels may lead to the condition of lymphedema, an accumulation of normal, non-infected lymph fluid within the tissues distal to the lymph blockage creating a swollen limb. Surgical disruption of lymph vessels or removal of lymph nodes is the major cause of lymphedema in developed countries (Figure 11.44). Lymphedema can be classified as mild (10%–20%), moderate (20%–40%), or severe (>40%), referring to the percentage of increase in limb volume. In mild and moderate cases, the involved limb is diffusely warmer than contralateral by up to 2°C (3.6°F), though this increase may not be present in the case of decreased arterial inflow. Also, as lymphedema becomes severe, skin warming may not be present due to decreased muscular activity, soft tissue degeneration, skin fibrosis, and deposition of dysfunctional subdermal fat in the affected limb.198
Introduction to Anatomy and Physiology
Published in Reginald L. Campbell, Roland E. Langford, Terry L. McArthur, Fundamentals of Hazardous Materials Incidents, 2020
Reginald L. Campbell, Roland E. Langford, Terry L. McArthur
Finally, very large particles such as bacteria can enter the system. As the lymph passes through the lymph nodes, these particles are removed and destroyed. Sometimes, though, the lymph nodes can be temporarily overwhelmed, as during a cold. The lymph nodes can become swollen and painful. Locations of lymph nodes under the neck and armpits are commonly swollen during infections.
Modelling uptake and transport of therapeutic agents through the lymphatic system
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
T. D. Jayathungage Don, V. Suresh, J. E. Cater, R. J. Clarke
The lymphatic system itself consists of different conduits, including the capillaries, collecting vessels, lymph nodes, trunks, and ducts. The lymphatic capillaries have an average diameter of 10-40μm (Moore Jr and Bertram 2018). These thin-walled vessels are embedded in the intercellular spaces and are connected to pre-collector vessels (diameter 50-100μm) that drain into the collecting vessels (diameter 50-500μm) situated in deeper tissue (Schmid-Schonbein 1990). This vessel network constitutes the peripheral lymphatics, and feeds into the central lymphatic vessels that ultimately return fluid to the right internal jugular vein and left subclavian vein.