Theme 1 : Anatomy part 2 Flashcards
What is the lymphatic system?
Morphologic counterpart of the immune system and monitors the body’s surfaces and internal fluid compartments and returns it to the venous system
What are the functions of the lymphatic system?
Fluid recovery
= Picks up excess tissue fluid (ECF and proteins) and returns into the blood stream
Immunity
= Filtration of fluids and Immune cells
Lipid absorption
= Lacteals absorb dietary lipids
What are the 4 main components of the lymphatic system?
Lymph
Lymphatic vessels
Lymphoid organs
Lymphocytes
What enters the lymphatic vessels?
Tissue fluid (interstitial fluid)
What is the tissue fluid comprised of?
Contains white blood cells.
Has a relatively high protein concentration
What is the normal lymphatic flow?
2L to 3L per day
What are the 2 components that fluids are made out of?
Intracellular fluid (ICF) 2/3
Extracellular fluid (ECF) 1/3
What is extracellular fluid comprised of?
Interstitial fluid 80%
Plasma 20%
How is the lymph formed?
when the interstitial fluid is collected through tiny lymph capillaries (not reabsorbed by the venous end)
Describe the lymph flow
Begins in the interstitial space (interstitial fluid)
Lymphatic plexuses
Lymphatic vessels
Lymph nodes
Lymphatic vessels
Lymphatic trunks
Lymphatic ducts
Venous circulation
Blood capillaries (blood)
Formation of lymph in interstitial space (cycle)
Describe what the Lymphatic Plexuses is structured like
Highly attenuated (thin) endothelium with valve-like flaps and no basement membrane. – one way valves
Where can I find Lymphatic Plexuses?
Originate blindly (blind end) in the extracellular spaces tethered to surrounding tissue
what areLymphatic Plexuses?
lymphatic capillaries that form large networks of channels
What are lacteals?
special types of lymphatic capillaries in the small intestine
What do lacteals pick up?
interstitial fluid, dietary lipids and lipid-soluble vitamins.
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What do lymphatic vessels do?
Lymphatic vessels drain lymph from the lymphatic capillaries (aka plexuses)
What are the 3 layers of the lymphatics vessels?
Endothelium
Tunica media
Tunica adventitia
How do lymphatic vessels differ from veins?
They are thinner than veins and have more numerous valves than in veins
What are interposed at the intervals of lymphatic vessels?
Lymph nodes
What is the difference between afferent and efferent lymphatic vessels?
Afferent lymph vessels bring unfiltered fluids from the body into the lymph node where they are filtered.
Efferent vessels, meaning away from, carry the clean fluid away and back to the bloodstream where it helps form plasma.
Describe the Superficial lymphatic vessels
Converges towards and follows venous drainage and eventually drains into deep lymphatic vessels
Describe the Deep lymphatic vessels
Accompany arteries and Receives drainage of internal organs
What are the similarities between superficial and deep lymphatic vessels?
Both traverse lymph nodes
Become larger and enter lymphatic trunks
What are the lymphatic trunks?
large collecting vessels that receive lymph from multiple lymphatic vessels.
Also known as collecting vessels
What does the union of the lymphatic trunks form?
either the right lymphatic duct or the thoracic duct
What are the 9 main lymphatic trunks we must know about?
The right and left…
Jugular trunk
Subclavian trunk
Bronchomediastinal trunk
Lumbar trunk
The intestinal trunk
What are lymphatic ducts?
collecting ducts that empty lymph fluid into the venous system
What does the right lumphatic duct do?
Drains lymph from the body’s right upper quadrant
(right side of the head, neck, and thorax plus the right upper limb)
To the junction of the right internal jugular and right subclavian vein
What does the thoracic duct do?
Drains lymph from the remainder of the body into the left internal jugular and left subclavian vein
What is the Cisterna chyli?
a dilated collecting sac formed by the merging of the lymphatic trunks draining the lower half of the body (originates)
What is the thoracic duct?
Largest lymphatic channel with numerous valves
Where does the thoracic duct originate?
cisterna chyli
Where does the thoracic duct ascend through?
aortic hiatus in the diaphragm
Where does the thoracic duct lie?
on the anterior surface of the vertebral bodies
What is the mediastinum?
A space in your chest that holds your heart and other important structures.
It’s the middle compartment within your thoracic cavity, nestled between your lungs.
What is the posterior mediastinum comprised of?
Left – thoracic aorta
Right – azygous vein
Anteriorly – oesophagus
Posteriorly – vertebral bodies
What are the primary lymphatic organs?
The bone marrow and the Thymus
Where do lymphocytes travel through?
enter the blood or lymphatic vessels to colonise secondary lymphatic organs and tissues, where they undergo the final stages of antigen-dependent activation
What are the secondary lymphatic organs?
Lymph nodes
Aggregation (cluster) of lymphatic nodules
Spleen
What are the Supporting elements of the lymph node?
Capsule – dense Connective tissue
Trabeculae – dense Connective tissue
Reticular tissue:
Reticular cells and fibres
Dendritic cells
Macrophages
What is the general architecture of the lymph node?
Cortex
Superficial – B cells & macrophages
Deep (paracortex) – T cells
Medulla
Lymph nodes filter lymph along the pathway of…
lymphatic vessels and initiate adaptive immune responses to antigens
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Describe the Superficial lymph nodes
Relative to the deep fascia
They run alongside superficial veins and drain the lymph to the deep lymph node
Describe the deep lymph nodes
closely located to vasculature and viscera
What does the Diffuse lymphatic tissue do?
Guard the body against pathogenic substances in the GI tract (GALT), respiratory system (BALT), and genitourinary tract (MALT).
Why is the diffuse lymphatic tissue important when you are sick?
Site for the initial immune response.
What is the diffuse lymphatic tissue Characterised by?
B cells and subsequent development oflymphatic nodules
What are Lymphatic nodules?
Dense oval masses of lymphocytes and macrophages - congregate in response to pathogens or are a permanent feature.
Where are lymphatic nodules found?
Are found in the GALT (tonsils, Peyer’s patches, solitary lymph nodules, and vermiform appendix), BALT (bronchial tree), and MALT (mucosa of urogenital system).
What are the 4 functions of the spleen?
Filters blood
Reacts immunologically to blood borne antigens
Removes senescent and defective erythrocytes
Recycles iron from degraded haemoglobin
What is the Largest lymphatic organ and is located in the abdominal cavity?
Spleen
What are the two major functional zones of the spleen?
White pulp – consists of lymphatic tissue
Red pulp - large numbers of erythrocytes, macrophages, and other immune cells.
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What is the mesothelium?
Layer with basement membrane covering internal surface of the thoracic cage and some organs
What is atherosclerosis?
thickening or hardening of the arteries. It is caused by a buildup of plaque in the inner lining of an artery.
Why is Atherosclerosis is not the same as arteriosclerosis?
Atherosclerosis happens when your arteries become narrow due to a buildup of plaque. It’s caused by inflammation in the arteries.
Atherosclerosis is a type of arteriosclerosis, a condition in which your arteries become stiff. Arteriosclerosis is caused by elastin fibers in your arteries losing elasticity.
What are the consequences of an acute thrombus?
Occlusion of the vessel and blood flow reduces or stops
Ischaemia (lack of blood flow) in the downstream areas
What do the consequences of an acute thrombus lead to?
Hypoxia (lack of oxygen)
Accumulation of harmful metabolites
Reversible cell injury
Irreversible cell injury
Cell death
What happens at 12 hours of someone with acute myocardial infarction?
coagulative myocardial necrosis?
When do eosinophils and neutrophils usually come in coagulative myocardial necrosis?
18 hours
In coagulative mycardial necrosis, which day does nuclei disapear in the
When is there no nuclei left in coagulative myocardial necrosis?
cardiac muscles
day 2
When do neutrophils flood in, in coagulative myocardial necrosis?
day 2 and 3
What happens from day 5 to someone with coagulative myocardial necrosis?
Macrophages causes Vasodilation (angiogenesis) and cause Early formation of granulation tissue
When does early fibrosis occur in coagulative myocardial necrosis?
Day 7 to 14
What can coagulative myocardial necrosis lead to?
myocardial scar but risk of myocardial rupture because granulation tissue is weak due to no collagen tissue
How many neurons are there?
~86 billion in human brain
What do neuroglia do?
- Support neurons
What is the soma?
The cell body of a neuron that synthesises proteins (e.g., ion channels and lots of ion channels)
Why is the soma important?
Important for cellular metabolism (lots of mitochondria)