The spleen filters blood and fights infections. It contains two types of tissues: white pulp contains lymphocytes that help produce antibodies when pathogens are detected, and red pulp contains cords and sinuses that remove old blood cells and filter the blood. The spleen helps fight encapsulated bacteria and stores extra red blood cells. It is not vital but its removal increases risk of certain infections.

1. THE SPLEEN
PHYSIOLOGY: GASTROINTESTINAL

2. FUNCTION OF THE
SPLEEN

3. FUNCTION OF THE SPLEEN
OVERVIEW
‣ The spleen is an organ the size of a fist found in the left upper quadrant
(LUQ) of the abdomen, under the protection of the inferior thoracic cage
‣ It is a soft, vascularized organ with a fibro-elastic capsule
‣ It is multi-functional yet not so vital that we can’t survive without it
‣ The spleen contains two types of tissues with different functions:
‣ white pulp and red pulp
‣ Learning Goal
‣ To discuss the function of each tissue within the spleen as well as
relevant clinical conditions

4. FUNCTION OF THE SPLEEN
WHITE PULP
‣ The white pulp comprises lymph-related nodules called
malpighian corpuscles which contain:
‣ Periarteriolar lymphoid sheaths rich in T-lymphocytes
and macrophages
‣ A marginal zone, rich in macrophages
‣ Lymphoid follicles, rich in naive B-lymphocytes

5. FUNCTION OF THE SPLEEN
WHITE PULP
‣ Because of this, the white pulp of the spleen has a very
important role in the normal immune response to infection
‣ Antigen presenting cells may enter the white pulp,
resulting in activation of the T-lymphocytes stored there
‣ These in turn, activate the B-lymphocytes in the follicles,
converting them to plasma cells which then produce of
IgM antibodies initially and eventually IgG antibodies

6. FUNCTION OF THE SPLEEN
WHITE PULP
‣ Pathogens may also enter the follicles directly
‣ B-lymphocytes detect this and can then present the
antigen to the T-lymphocytes
‣ This leads to a process known as co-stimulation, in which
the two cell types activate each other
‣ so the B-lymphocyte is then able to become a plasma
cell and produce antibodies against the pathogen

7. FUNCTION OF THE SPLEEN
WHITE PULP
‣ The white pulp is also important in how the body deals
with encapsulated bacteria
‣ e.g. Neisseria meningitidis, Haemophilus influenzae and
Streptococcus pneumoniae
‣ Encapsulated bacteria tend to have a very smooth surface with
a negative charge which therefore reduces the ability of
phagocytes to attach and engulf the bacteria
‣ The B-lymphocytes in the white pulp help opsonise these
bacteria

8. FUNCTION OF THE SPLEEN
RED PULP
‣ The red pulp makes up roughly 80% of the spleen
parenchyma
‣ It is separated from the white pulp by the marginal zone
‣ The red pulp is primarily made up of tissue known as
the cords, which is rich in macrophages, and the venous
sinus

9. FUNCTION OF THE SPLEEN
RED PULP
‣ The functions of the red pulp include:
‣ Removal of old, damaged and dead red blood cells along with antigens and
microorganisms – the venous sinuses have gaps in the endothelial lining
which allows normal cells to pass through, abnormal cells remain in the cords
and are phagocytosed by macrophages
‣ Phagocytosis of opsonised bacteria by macrophages
‣ Sequestration of platelets
‣ Storage of red blood cells in case of hypovolemia, these can then be released
following an injury resulting in blood loss
‣ Prenatally, it is hematopoietic until about the fifth month of gestation when
bone marrow becomes the main site for hematopoiesis

10. https://teachmephysiology.com/gastrointestinal-system/spleen/function-of-spleen/

11. https://teachmephysiology.com/gastrointestinal-system/spleen/function-of-spleen/

12. https://teachmephysiology.com/gastrointestinal-system/spleen/function-of-spleen/

13. https://teachmephysiology.com/gastrointestinal-system/spleen/function-of-spleen/

14. FUNCTION OF THE SPLEEN
REVIEW QUESTIONS
‣ Which bacterial infections are asplenic individuals
susceptible to?
‣ Streptococcus pneumoniae, Haemophilus Influenzae,
Neisseria Mengingitidis
‣ Klebsiella Pneumoniae
‣ E coli
‣ Pseudomonas aeruginosa

15. FUNCTION OF THE SPLEEN
REVIEW QUESTIONS
‣ Which bacterial infections are asplenic individuals susceptible to?
‣ Streptococcus pneumoniae, Haemophilus Influenzae,
Neisseria Mengingitidis
‣ Klebsiella Pneumoniae
‣ E coli
‣ Pseudomonas aeruginosa
‣ Asplenic individuals are at risk of infections from encapsulated
bacteria

16. FUNCTION OF THE SPLEEN
REVIEW QUESTIONS
‣ What is the function of white pulp of the spleen?
‣ Removal of old red blood cells, antigens,
microrganisms
‣ Sequesters platelets
‣ Storage of Red blood cells
‣ Important in the normal response to an infection,
activates B and T cells

17. FUNCTION OF THE SPLEEN
REVIEW QUESTIONS
‣ What is the function of white pulp of the spleen?
‣ Removal of old red blood cells, antigens,
microrganisms
‣ Sequesters platelets
‣ Storage of Red blood cells
‣ Important in the normal response to an infection,
activates B and T cells

18. FUNCTION OF THE SPLEEN
REVIEW QUESTIONS
‣ Which is of the following are causes of splenomegaly?
‣ Edema
‣ Iron deficiency anemia
‣ Weight gain
‣ Infection, Hemolytic anemia

19. FUNCTION OF THE SPLEEN
REVIEW QUESTIONS
‣ Which is of the following are causes of splenomegaly?
‣ Edema
‣ Iron deficiency anemia
‣ Weight gain
‣ Infection, Hemolytic anemia

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