Spleen Flashcards

1
Q

What system is the spleen part of?

A

Reticuloendothelial system

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2
Q

What process do all cells and tissue exhibit?

A

Phagocytosis

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3
Q

Where does hematopoiesis occur within a fetus?

A

Spleen, liver and bone marrow

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4
Q

Where does hematopoiesis occur postnatally?

A

Bone marrow

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5
Q

What is included within the RE system?

A

Brain, blood, spleen, liver, thymus, bone marrow and lymph nodes

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6
Q

What is blood composed of?

A

RBCs, WBCs, platelets (thrombocytes) and plasma

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7
Q

How many leukocytes are there per cubic mm?

A

5,000 - 10,000

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8
Q

What is leukocytosis?

A

Rapid division of cells in the presence of infection

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9
Q

What is leukopenia?

A

Decrease amount of leukocytes

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10
Q

When is there a decrease of leukocytes?

A

Drug and chemical toxicity and viral infections

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11
Q

What are the 5 different types of leukocytes?

A
  1. Neurophil
  2. Eosinophils
  3. Monocytes
  4. Lymphocytes
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12
Q

What WBCs perform phagocytosis?

A

Neutrophils, eosinophils and monocytes

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13
Q

What WBCs are non-phagocytic cells?

A

Lymphocytes

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14
Q

Describe the 3 processes of immune response

A
  1. Body recognizes the chemical composition of substances and decides if its alien or not
  2. If the body is alien it reacts and produces antibodies and anti-toxins
  3. Body produces memory cells- antibodies and antigens are produce specific antigen
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15
Q

What is a humoral immune response?

A

Antibodies (gamma globulins) are liberated into the plasma by committed lymphocytes

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16
Q

What is a cell mediated immune response?

A

Lymphocyte produces antitoxins that are retained within lymphocyte cell

Lymphocyte attaches to antigen and secretes antitoxin

Both antigen and lymphocyte die and are absorbed

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17
Q

What is the largest unit of the RE system?

A

Spleen

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18
Q

When does the spleen develop?

A

5th week gestation

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19
Q

What type of cells does the spleen arise from?

A

Mesodermal cells

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20
Q

When does the spleen start performing hematopoietic functions?

A

Starting at 11 weeks gestation

This function ends shortly after birth

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21
Q

When does the spleen assume adult function?

A

5th or 6th month gestation

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22
Q

What cavity is the spleen located in?

A

Retroperitoneal

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23
Q

Is the hilum covered in peritoneum?

A

No

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24
Q

Is the spleen encapsulated?

A

Yes

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25
Q

What quadrant does the spleen lye in?

A

LUQ

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26
Q

What rib does the long axis of the spleen lye by?

A

10th rib

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27
Q

What ligaments anchor the spleen in place? (3)

A
  1. Gastrosplenic
  2. Splenorenal
  3. Phrenocolic
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28
Q

What structure is superior/lateral/posterior to the spleen?

A

Diaphragm

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29
Q

What structures are medial to the spleen? (4)

A
  1. Stomach
  2. Tail of pancreas
  3. Splenic flexure of colon
  4. Left kidney
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30
Q

What structure is anterior to the spleen?

A

Stomach

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31
Q

What is the average adult size of the spleen?

A

L: 11cm but not > 12cm
W: 7-8cm
H: 3-4cm

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32
Q

What is the normal size of the spleen?

A

Up to 12cm

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33
Q

What is the moderate size of the splenomegaly?

A

> 12 -18cm

34
Q

What is the size of severe splenomegaly?

A

> 18cm

35
Q

When is the spleen is considered enlarged?

A

In decubitus position: more then twice the size of the kidney
Visualize a flattened caudal kidney

36
Q

What occurs to the size of the spleen as you age?

A

Decreases in size

37
Q

How is the spleen shaped?

A

Crescent-shaped

Lateral- smooth convex side in contact in left hemisphere
Medial- concave side contains central hilum

38
Q

What forms the splenic vein?

A

Smaller splenic veins converging at the hilum

39
Q

The splenic artery branch into how many smaller arteries?

A

6

40
Q

Which ligament do the vessels course through?

A

Splenorenal ligament

41
Q

How does the splenic vein communicate with celiac nodes?

A

Efferent lymphatics

42
Q

Is the spleen essential for life?

A

No- but immune response may be impaired if removed in childhood

43
Q

How is the spleen divided into lobules?

A

Via projections of connective tissue capsule

44
Q

What are the 2 types of pulp the lobules are divided into?

A
  1. Red pulp

2. White pulp

45
Q

Describe red pulp

A

Venous component
Meshwork of splenic sinuses alternating with splenic cords (cords of billroth)
Phagocytic cells line the sinusoids

46
Q

Describe white pulp

A

Tiny islands of lymphatic tissue consisting- lymphocytes and macrophages
Major site of immunological activity- lymphatic follicles (malpighian corpuscles) responsible for production of antibodies

47
Q

What is the function of the RE?

A

Produce lymphatics and plasma cells (antibodies)

Storage of iron and metabolites

48
Q

What is the primary function of the spleen?

A

Filter blood

Culling- removes destroys imperfect/defective RBCs

Pitting- removes granular inclusions in the RBCs

49
Q

What are other functions of the spleen?

A

Blood reservoir

Erythropoiesis

50
Q

How much blood can the spleen hold?

A

50-1000ml

51
Q

What takes over erythropoiesis after birth?

A

Bone marrow

52
Q

Does the spleen retain the ability of erythropoiesis after birth?

A

Yes

53
Q

What is the pt prep for the spleen?

A

Overnight fast (6-8 hours)

54
Q

What transducer is used for the spleen?

A

3.5-5.0 MHz

55
Q

What do you evaluate the spleen for?

A

Size, position, focal abnormalities and surrounding fluid

56
Q

What does the sagittal plane show in for the long axis?

A

Superior and inferior tips of spleen

57
Q

How do you image the spleen in the transverse plane?

A

Always 90deg the long axis

58
Q

When can the spleen be used as a sonographic window?

A

Pancreatic tail and left kidney

59
Q

What is the sonographic appearance of the spleen?

A

Homogeneous- low to medium level echos

60
Q

Compare the echogenicity of the spleen to the kidney

A

More echogenic

61
Q

Compare the echogenicity of the spleen liver

A

Isoechoic or slightly more echogenic

62
Q

What is a pseudoperisplenic lesion?

A

Lesion that mimics a sub capsular hematoma or abscess

63
Q

Where is a pseudoperisplenic lesion found?

A

Left lobe of the liver identified superior to the spleen

64
Q

What type of people are more likely to have a pseudoperisplenic lesion?

A

Thin pts and children

65
Q

What structures can be mistaken for a mass when scanning the spleen?

A

Fluid filled stomach or tail of pancreas

66
Q

What is a “born again” spleen?

A

Hypertrophy of an accessory spleen or other splenic tissue post-splenectomy (due to components of blood)

67
Q

What are the 4 lab tests used to identify function of the spleen?

A
  1. Hematocrit
  2. Hemoglobin
  3. WBCs
  4. Platelets
68
Q

What does hematocrit identify in the blood?

A

% of RBCs per volume of blood

69
Q

What can cause hematocrit to decrease?

A

Hemorrhage or internal bleeding

70
Q

What is hemoglobin responsible for?

A

Protein in RBCs responsible for transporting oxygen

71
Q

What can cause a decrease in hemoglobin?

A

Acute blood loss, anemia, leukaemia and multiple myeloma

72
Q

What is leukocytosis?

A

Increased WBC count

73
Q

When can leukocytosis occur?

A

Acute infection, leukaemia, malignancies and stress

74
Q

What is leukopenia?

A

Decreased WBC count

75
Q

What is another name for platelets?

A

Thrombocytes

76
Q

What is thrombocytopenia?

A

Decreased platelets in blood

77
Q

What conditions can cause thrombocytopenia?

A

Internal hemorrhage, leukemia or Vit B12 deficiency

78
Q

What is thrombocytosis?

A

Increased platelets in the blood

79
Q

What conditions can cause thrombocytosis?

A

Hemorrhage or infective disorders

80
Q

What are other imaging modalities that can look at the spleen?

A
  1. Nuclear medicine- RBC scan (radioactive tracer injected into blood- used to assess morphology of spleen (splenic volume))
  2. CT