Overview of the lymphatic and immune system Part1

   

LYMPHATIC SYSTEM

Lymphatic system: It is a network of vessels, organs and tissues containing lymph which is a fluid containing infection-fighting white blood cells that spreads throughout the body.

Also a part of circulatory system and plays a vital role to our immune system

Lymph is the interstitial fluid that gets absorbed when forced out of the capillary tubes.

-One function of the lymphatic system is that it maintains our body's homeostasis.

Homeostasis means balance, a way or process your body does by controlling the concentrations of substances in solution, temperature, etc.. in order to remain everything near constant level, the plasma membrane is so related to homeostasis so check out the last video below for more understanding.

Any failure to perform homeostasis may lead to life threatening consequences such as swelling ankles, lungs can be filled by fluids, the failure to control concentrations can decrease the blood pressure and volume.

Lymphatic system structure:

1-Lymph, a watery(liquid) solution which is most likely to be plasma and NOT blood; because red blood cells are big enough that they cannot squeeze out of your capillaries

Mainly consists of blood plasma which is forced out of your capillaries where the leakage helps the exchange of nutrients and gases between the blood and capillaries and the cells.

2-Lymph nodes, network of lymphatic vessels reabsorb the blood fluid (lymph) which transport them to lymph nodes which are found at certain points throughout the body, they  are more likely to be your checkpoints, they help in monitoring/cleaning/eliminating any microbes or such foreign bodies present in your lymph.

3-Lymphatic organs: a-Spleen( major lymphatic organ) found in a suitable and safe place behind the stomach and just in the front of the left lobe of your liver, spleen has various functions such as getting rid off of dead red blood cells, oxygen-rich blood reservoir and cleans the blood off foreign invaders

b-Thymus gland, a gland that exists in your neck behind the sternum in an appropiate place between your lungs, also provide a vital immunity role to your body by secreting thymosin hormone which stimulates the maturation of disease-fighting lymphocytes called T-lymphocytes

c-Adenoids

d-Tonsils

Both the spleen & thymus provides a safe place for immune cells such as T and B cells, natural killer cells, dendritic cells and R.B.Cs.

Starting from the capillaries......,

The capillaries are tiny, microscopic vessels which connects the arterioles with the venules.

Carries blood from your arterioles and feed blood into venules, their walls which are very thing consists of one row of thing epithelial cells with tiny pores between them, the wall of the capillary is about 0.001 micron thick which facilitates a quick exchange of substances between the blood and the tissue cells.

Capillaries are spread in the spaces present all over the body tissues as a wide irrigation system.

The exchange of nutrients and gases is due to osmotic pressure, it is the diffusion of solutions/substances through a semi-permeable membrane, it increases by the increase in concentration of solutes in solutions.

-About 3 liters per day  of the fluids which is about more than half of your total blood volume  that passes through the blood capillaries are picked up by the lymphatic capillaries that exists through the spaces present in the capillary vessels. Their walls consist of endothelial cells with valves that opens only in one direction, the presence of smooth muscles in the inner lining roles in moving the lymph as well as the skeletal muscles which when squeezing (contracting) increases the pressure on the lymphatic vessels and therefore, the lymph moves forward.

These walls are forced to be opened when the concentration of solutes on the outside is more than that on the inside of the lymphatic vessel. Once filled, it is then taken to various nodes and are eventually drained into two big ducts.

-The right lymphatic duct takes lymph from the upper right area of the Torso, including the right upper arm and right side of the head & thorax feeding all into the Internal Jugular Vein ( a major blood vessel that drains blood from important body organs and parts such as the brain, face and neck, they functions in carrying oxygen-depleted (less) blood from the brain, face and neck and transport it to the heart through the superior vena cava).

-The larger thoracic duct takes lymph from the rest if your body sending them into the subclavian vein.

Lymphatic vessels works under low pressure, containing valve that prevents any back flows as well as the presence of smooth muscles that help in movement and support.

Any decent exercises or movements are good enough to help keep up your lymphatic vessels.

Ultimately, the lymphatic system functions in taking extra fluids and cleans it from any microbes.

Now back to the vital role of the lymphatic system to our immune system, throughout our lives our skin which is considered to be the largest organ is surrounded by many bacteria that standing for any chance to infect your body starting from a small cut in your skin.

For example, staphylococcus bacteria (gram +ve bacteria) sneaks through your loose areolar connective tissue ( a multi-functional tissue that serves structural, adhesive, and immunological functions consists of collagenous fibers and elastic fibers )

Recall lymph nodes....?

Since they contains the checkpoints in other words, the protection against foreign bodies that wants to breach our body, it is also the place for lymphocytes exists (T & B) and where they mature in the loose reticular connective tissue that makes up a large part of the nodes and most of your other lymphoid organs.
-Lymph enters the lymph nodes through a vessel called Afferent vessel  and exits through Efferent vessel

Mucosa associated lymphoid tissues

a.k.a MALTs are also tissues that functions like our lymph nodes such as tonsils (two small masses of lymphoid tissues in the throat), Mucosa? because they are present in the mucous membrane outside the lymphatic vessels, the tonsils inspect everything that you eat, another example is peyer's patches found in the distal portion of small intestines ( consists of a group of lymph nodes) also appendix ( which happens to have lymphatic nodes & vessels)

Figures

Diagram of a lymph node showing its structure

Picture showing the structure of a lymphatic vessel

Diagram of the lymphatic vessel showing its structure and its histology

Loose reticular connective tissue diagram

Diagram showing lymph capillaries in between blood capillaries

Loose areolar connective tissue

I hope you guys enjoyed the topic today, the following videos will help you revise and understand with extra information about the lymphatic system, I don't own any of the following videos also stay tuned for more biology stuff and the next parts of this overview =) WE LIVE WE LEARN

Thanks to Tammy Moore, here is her channel https://www.youtube.com/user/armoorefam

Thanks to CrashCourse, channel's link: https://www.youtube.com/user/crashcourse

Thanks to Jenny Klemme, here is her channel: https://www.youtube.com/channel/UC1WLVcjqO44TPUnV2zvPrcQ

Thanks to Amoeba sisters, link to their channel: https://www.youtube.com/channel/UCb2GCoLSBXjmI_Qj1vk-44g

Next part will be more into the immune system deeper into it, we will discuss immune cells their functions also we will have an example to help in understanding what happens when the body is infected, it will be about bacterial infection.

What you want to know about ''Homeostasis'' is here,

A quick peek about the various body tissues we got