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Anatomy of the lymphatic system

The left panel shows a female human body, and the entire lymphatic system is shown. The right panel shows magnified images of the thymus and the lymph node. All the major parts in the lymphatic system are labeled.
Lymphatic vessels in the arms and legs convey lymph to the larger lymphatic vessels in the torso.

A major distinction between the lymphatic and cardiovascular systems in humans is that lymph is not actively pumped by the heart, but is forced through the vessels by the movements of the body, the contraction of skeletal muscles during body movements, and breathing. One-way valves (semi-lunar valves) in lymphatic vessels keep the lymph moving toward the heart. Lymph flows from the lymphatic capillaries, through lymphatic vessels, and then is dumped into the circulatory system via the lymphatic ducts located at the junction of the jugular and subclavian veins in the neck.

Lymphatic capillaries

Lymphatic capillaries , also called the terminal lymphatics, are vessels where interstitial fluid enters the lymphatic system to become lymph fluid. Located in almost every tissue in the body, these vessels are interlaced among the arterioles and venules of the circulatory system in the soft connective tissues of the body ( [link] ). Exceptions are the central nervous system, bone marrow, bones, teeth, and the cornea of the eye, which do not contain lymph vessels.

Lymphatic capillaries

This image shows the lymph capillaries in the tissue spaces, and a magnified image shows the interstitial fluid and the lymph vessels. The major parts are labeled.
Lymphatic capillaries are interlaced with the arterioles and venules of the cardiovascular system. Collagen fibers anchor a lymphatic capillary in the tissue (inset). Interstitial fluid slips through spaces between the overlapping endothelial cells that compose the lymphatic capillary.

Lymphatic capillaries are formed by a one cell-thick layer of endothelial cells and represent the open end of the system, allowing interstitial fluid to flow into them via overlapping cells (see [link] ). When interstitial pressure is low, the endothelial flaps close to prevent “backflow.” As interstitial pressure increases, the spaces between the cells open up, allowing the fluid to enter. Entry of fluid into lymphatic capillaries is also enabled by the collagen filaments that anchor the capillaries to surrounding structures. As interstitial pressure increases, the filaments pull on the endothelial cell flaps, opening up them even further to allow easy entry of fluid.

In the small intestine, lymphatic capillaries called lacteals are critical for the transport of dietary lipids and lipid-soluble vitamins to the bloodstream. In the small intestine, dietary triglycerides combine with other lipids and proteins, and enter the lacteals to form a milky fluid called chyle    . The chyle then travels through the lymphatic system, eventually entering the liver and then the bloodstream.

Larger lymphatic vessels, trunks, and ducts

The lymphatic capillaries empty into larger lymphatic vessels, which are similar to veins in terms of their three-tunic structure and the presence of valves. These one-way valves are located fairly close to one another, and each one causes a bulge in the lymphatic vessel, giving the vessels a beaded appearance (see [link] ).

The superficial and deep lymphatics eventually merge to form larger lymphatic vessels known as lymphatic trunks    . On the right side of the body, the right sides of the head, thorax, and right upper limb drain lymph fluid into the right subclavian vein via the right lymphatic duct ( [link] ). On the left side of the body, the remaining portions of the body drain into the larger thoracic duct, which drains into the left subclavian vein. The thoracic duct itself begins just beneath the diaphragm in the cisterna chyli    , a sac-like chamber that receives lymph from the lower abdomen, pelvis, and lower limbs by way of the left and right lumbar trunks and the intestinal trunk.

Questions & Answers

How does the male organ develop
MADUBULA Reply
Hw does the male organ develop
MADUBULA
Review your questions madam
Aliyu
what is anaphylaxis?
Rugut Reply
different between drug and medicine
ado Reply
drugs have no medical application (cocaine, heroin, crystal meth). medicine have medical purpose (fentanyl, albuterol, aspirin, ect ect)
Jordan
medicine is a substance or preparation used in treating disease,drug is chemical compound medicine are drugs but all drugs are not medicines
Wafa
assalam o alaikum
Sidra
what happen to ECF and ICF regarding to OEDEMA
Zwanga Reply
what are the smooth muscles of the heart
Sintung Reply
stomach
Sidra
identify external features of kidney
saba Reply
kidney weight on males?
saba
3 to4 onz and 140 gram kidney wight.adult
StudyTime
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saba
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Samim
Syplymic lupw erythematous
Samim
blood supply to spleen ?
saba
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Samim
saba
StudyTime
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saba
do u know female kidney wight?
StudyTime
ya 135 g females
saba
Please help me
Samim
130 on male
saba
130g on male
saba
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StudyTime
approximate 140grms in adultkidny wight
StudyTime
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saba
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saba
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saba
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Shahab
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saba
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Define cranial nerves with oder
Javid
O-olfactory O-optic O-occumulator T-trochlear T-trigemenal A-abducent F-facial A-auditory G-glossopharyngeal V-vagus A-acessory
Aniee
opd mean?
Shahab
out patient department
mahesh
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Shahab
Ty Aniee singh
Javid
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Areeej
Read KD Tripathi book of Pharmacology.
mayank
Hello
mayank
CT Scan means
Sintung
what's health?
Sintung
hello
Philip
hi
Sintung
CT means - computerized tomography
Vivek
connective tissue
Dee
they link some body organs
Sintung
Difference between drug and medicine
Javid
hiii muskan
saba
what is tomography?
Gideon
tomography ☝
shahid
yes
Gideon
how hemolytic anemia cause due to gas gangrene?
Huma Reply
what's gangrene?
Sidra
why retro abdominal region called or named "flank "?
Huma Reply
list types epithelial tissue
Sangu Reply
Squeamus epithelial tissu Cubidal Columna Cilliated columna
Aliyu
squamous cuboidal columnar ciliated stratified
Ken
psuedostratified ciliated columnar stratified squamous transitional epithelium
Espinoza
peace maker of heart is?
shahid
electrical conduction ... sa node
Dee
squamous epithelial tissue.
Tariq
squamous, stratified epithelial tissue
Sintung
explain how hormonal control aids in homeostasis regarding fluids and electrolytes, internal organs, clinical application, edema electrolyte imbalance?
Hensheal Reply
someone to help me explain those
Hensheal
parathyroid hormone : Calcium uptake, H+ and PO-4 wasting thyroid hormone, cortisol for temperature regulation by acting on B.V
Kartik
also renin
Kartik
thanks
Hensheal
why retro abdominal region called flank?
Huma
it is just Anatomical terminology
Kartik
meaning side of body b/w rib cage and hip bone
Kartik
list down all the hormones secreted by adrenal gland
Odong Reply
adrenaline hormones
Sangu
adrenaline and noradrenaline
Sintung
The amount of blood pumped by the left ventricle of the heart in one contraction.
Javid Reply
how we can calculate the cardiac output
khater
and how do we calculate the strock valume
khater
stroke volume is not all the blood contained in the left ventricle; normally, only about two-thirds of the blood in the ventricle is expelled with each beat.
Javid
Cardiac output 5.5 l S. V 68.75 ml H. R 80bpm
Javid
If we consider SV 70, end systolic vol is about 15% of total(approx always) out of a total of 80-85 ml only 70ml is pumped per systole
Kartik
what is macrophages?and its function
Sajjad Reply
macrophages they are white blood cells that engulf dead cells in the body
patience
what is power stroke?
muravha
no idea
patience
what is the stroke volume of heart?
up
the amount of blood that enters the heart
Sintung
wrong^^ stroke volume is the amount of blood ejected from the left ventricle on a single contraction.
Jordan
If an autoimmune disorder targets the alpha cells, production of which hormone would be directly affected?
Samantha Reply
what is a muscle?
Gideon Reply
A band or bundle of fibrous tissue in a human or animal body that has the ability to contract, producing movement in or maintaining the position of parts of the body
Mody
ok
Gideon
what's endolphthamities and panophthalmities?
Gideon

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Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
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