Session 7 - Lymphatic and Immune System 1 Flashcards

1
Q

Function of lymphatic system

A
  • Drain excess interstitial fluid and large proteins from tissue spaces
  • Transporting dietary lipids and vitamins from GI tract to the blood ( Its role in nutrition)
    • Facilitate immune responses - recognise microbes or abnormal cells and responding by killing them directly or secreting antibodies that cause their destruction
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2
Q

Excess interstital fluid comes from?

and what happens to it?

A

At our capillary beds there is a little more filtration than there is absorption and that is the excess interstitial fluid that is then taken up by lymphatic system and returns back to the cardiovascular system.

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3
Q

Lymphatic fluid

A

similar in compostion to interstitial fluid but some differences in (protein) do occur

Major difference is location

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4
Q

Lymphatic system consists of

A
  • Lymph: the fluid
  • Lymphatic vessels: transport the lymph
  • Lymphatic organs and tissue: made of specialized form of reticular connective tissue that contains large numbers of lymphocytes
  • Red bone marrow: the site of lymphocyte production
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5
Q

Connection of lymph nodes to organs creates

A

Lymph vessels

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6
Q

Lymphatic capillaries unite to form

A

Lymph capillaries merge to form larger vessels, called lymphatic vessels, which convey lymph into and out of structures called lymph nodes

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7
Q

Lymphatic Vessles unite to form

A

lymphatic trunks and thoracic ducts - vessels are similar in structure to veins but are thinner walled and have more valves

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8
Q

Lymph trunks

A

Lymphatic vessels exit lymph nodes in a particular region of the body, they unite to form lymph trunks

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9
Q

Lymphatic vessels ( supply and exit )

A

There are lymphatic vessels that supply the lymph nodes and also lymphatic vessels that leave the lymph nodes that unite to form lymph trunks

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10
Q

Lymph ducts

A

Lymph passes from lymph trunks into two main channels, the thoracic duct and the right lymphatic duct, and then drains into venous blood.

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11
Q

Where are lymphatic capillaries located

A

Throughout the body along the systemic circulation

  • not present in avascular tissue (cartilage, epidermis and cornea), the central nervous system, portions of the spleen, and red bone marrow.
  • specialized lymphatic capillaries in the villus of the small intestine, transport digested fats from the small intestine into the blood.
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12
Q

Lymph ducts

A

Lymph passes from lymph trunks into two main channels, the thoracic duct and the right lymphatic duct, and then drains into venous blood.

  • Right side - head, arm and chest empty into right lymphatic duct
  • Rest of body empties into thoracic duct
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13
Q

Thoracic ducts drain lymph into venous blood into

A

left subclavian vein which in turn return it to the circulatory system via the superior vena cava

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14
Q

Right lymphatic duct

A

Receives lymph from the upper right side of the body

•It drains lymph into venous blood via the right subclavian vein.

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15
Q

sequence of lymph flow

A

blood capillaries (blood)→interstitial spaces (interstitial fluid) → lymphatic capillaries (lymph)→lymphatic vessels (lymph)→lymphatic ducts (lymph)→junction of the internal jugular and subclavian veins (blood)

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16
Q

What promotes flow of lymphatic fluid

A

Respiratory and muscular pumps

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17
Q

Fluid and proteins escaping from vascular capillaries (pulmonary blood capillaries, systemic blood capillaries) is collected by

A

lymphatic capillaries and returned to the blood

18
Q

Lymphatic organs and tissues

A
19
Q

Primary lymphatic organs

A

Provide environment for stem cells to divide and mature into B and T lymphocytes - Provide the source of immune cells ( B and T ) that circulate through the lymphatic system.

 Red bone marrow gives rise to mature B cells

 Thymusis the site where pre-T cells from red marrow mature

20
Q

Secondary lymphatic organs and tissues

A

site where most immune responses occur

Lymph nodes - Acts as filter for the blood and picks up external antigens and external pathogens

Spleen - big site for where red blood cells are digested and recycled. Has a due role, has a big immune function also - Quite a large amount of B cells and T cells in the spleen

Lymphatic nodules/follicles - distribute throughout particular tissues, very important in the gut. Play a huge role in gut immune access.

21
Q

Red bone marrow (primary lymphatic organs and tissues)

A

oLocation:

•In flat bones and the epiphyses of long bones of adults

Source of red blood cells, source of platelets, source of all the other white blood cells, source of production for B cells, also where they mature before they leave into the lymphatic system and immature T cells.

22
Q

Thymas gland location and function

A

•Between the sternum and the aorta

Structure -

  • 2 lobed organ: Capsule and trabeculae divide it into lobules
  • Each Lobules has Cortex (outer) and Medulla (inner)

oFunction:

  • Cortex:proliferation and maturation of Immature T cells (pre-T cells) migrated from red bone marrow
  • Medulla:Release of mature and immunocompetent T cells into blood to migrate to lymph nodes and other lymph organs
23
Q

Lymph nodes - location and structure

A

oLocation:

  • All along lymphatic vessels
  • about 600 lymph nodes, scattered throughout the body, both superficially and deep, and usually occur in groups
  • Large groups are present near the mammary glands and in the axillae and groin.

oStructure:

  • encapsulated Bean-shaped organs,
  • Two parts:

–The stroma: supporting framework of connective tissue

–The parenchyma: functioning part

24
Q

Parenchyma is divided into 2 regions..

A
  1. Cortex: outer and inner
  2. Medulla
25
Q

Route of lymph flow through lymph node

A

Afferent lumphatic vessel (entry) > subcapsular sinus > Trabecular sinus > Medullary sinus > Efferent lymphatic vessel (exit)

26
Q

Outer cortex of lymph nodes

A

Consists lymphatic nodules/follicles called a Germinal center

–This is the site for B cells proliferation and differentiation into antibody-secreting plasma cells

–Also the site for where memory B cells are presented with an antigen by dendritic cells

Swollen lymph nodes = B cells are growing and making lots of antibodies. Swollen lymph nodes because B cells in the outer cortex are growing and proliferating and antibodies being made and then they are being released into your circulation

27
Q

Lymph nodes - inner cortex and medulla

A

oInner cortex:

‒Consists mainly of T cells and dendritic cells that enter a lymph node from other tissues.

‒Site for T cells proliferation when dendritic cells present antigens to T cells. The newly formed T cells then migrate from the lymph node to areas of the body where there is antigenic activity.

oMedulla:

‒contains B cells, antibody producing plasma cells that have migrated out of the cortex into the medulla, and macrophages

28
Q

Lymph nodes function

A

Acts as a filter

  • Many afferent vessels : Few efferent vessels
  • Slow flow - The slow flow enables the lymph node to sample the lymph, see what’s in it - are there any foreign antigens, any viruses, bacteria,
  • Lymph flows through many lymph glands to increase exposure
  • Within lymph glands macrophages destroy some foreign substances by phagocytosis and lymphocytes (B cells and T cells) bring about the destruction of others by immune responses.

oSite of proliferation of Plasma cells (antibody secreting B cells) and T cells.

Simply put - Site for Where we produce antibodies - when the B cells remember the antigen, or remember a previous infection they turn into a plasma cell and make the antibodies that are designed to bind and destroy the antigen.

29
Q

What is metastasis?

Metastasis through lymphatic system - define and give examples

A

Metastasis: The spread of a disease (cancerous tissue) from one part of the body to another.

o A characteristic of malignant ( has the abilty to spread - metastasis) tumours

  • • cancer cells travel via blood or lymphatic system
  • • cells establish new tumours where they lodge

o Secondary tumour sites: can be predicted by the direction of lymphatic flow from the primary site

o Cancerous lymph nodes are enlarged, firm and non-tender

o Infected lymph nodes are enlarged but not firm and are very tender

30
Q

Spleen location and structure

A

oLocation:

•between the stomach and diaphragm

oStructure:

  • the largest single mass of lymphatic tissue
  • measuring about 12 cm
31
Q

Spleen function ( 2 pulps )

A

White pulp: Lymphatic tissue. B Cells, T Cells and macrophages perform immune function (similar to lymph node process’)

Red pulp: consists of venous sinuses filled with blood and splenic tissue. Removal of ruptured worn out RBC. Storage of platelets.

32
Q

Lymphatic nodules

A

oLymphatic Nodules/follicles: egg-shaped masses of lymphatic tissue that are not surrounded by a capsule

oLocation: scattered throughout connective tissue of mucous membranes

•Also known as mucosa-associated lymphoid tissue (MALT)

oLarge aggregations in specific parts:

•Peyer’s patches:In the ileum of the small intestine, really important in the gastronomical tract ( stomach, intestines) - when we eat any bacteria etc on food the nodules will detect.

•Appendix

•Tonsils: form a ring at the top of throat –

–Adenoids/pharyngeal tonsil: in the posterior wall of the nasopharynx

–Palatine tonsils: at the posterior region of the oral cavity, one on either side

–Lingual tonsil: at the base of the tongue

33
Q

Immunity is..

A

the ability to ward off damage or disease through our defences.

34
Q
A
35
Q

What are the 2 types of immunity?

A

oInnate (nonspecific) immunity: defences that are present at birth

oAdaptive/acquired (Specific) immunity: refers to defences that involve specific recognition of a microbe once it has breached the innate immunity defences.

36
Q

What forms the basis of Innate immunity

A
37
Q

First line of defence ( innate immunity )

A

oThe first Line of defence: The external physical and chemical barriers provided by the skin and mucous membranes

oPhysical barriers:intact epidermis layer of the skin, mucous membranes and the lacrimal apparatus.

oChemical barriers: is localized on the skin, in loose connective tissue, stomach, and vagina.

38
Q

List the components of the lymphatic system

A

Consists of Lymph (Fluid), Vessels that transport lymph, and organs that contain lymph tissue ( lymph nodes, spleen, thymus, )

39
Q

How do lymph vessels differ from blood vessels?

A
  • The main purpose of lymphatic vessels is to absorb and return lymph fluid from the body back to the blood, and to assist in the body’s immune function.
  • blood and blood vessels to deliver oxygen and nutrients to organ systems and tissues, and to remove waste products resulting from metabolism.
40
Q
A