C10: Spleen

Question 1

the reticuloendothelial system (RE) is composed of what type of cells?
what the RE sys general function

Answer 1

• cells and tissue that carry out phagocytosis

- body’s major defence systems against infection… other functions depend on the organ

Question 2

what does hematopoiesis occur in the RE system?

Answer 2

• spleen, liver, bone marrow in the fetus

- bone marrow post natally…. spleen can also form new blood cells if needed

Question 3

which organs are included in the RE system

Answer 3

brain
blood
spleen, liver, thymus
bone marrow
lymph nodes

Question 4

list the elements that make up the composition of blood

Answer 4

erythrocytes, thrombocytes, leukocytes and plasma

Question 5

describe the function of leukocytes.

how many different types are there

1. what is leukocytosis… what does it indicate
2. what is leukopenia… what does it indicate

Answer 5

-important for immunity

5 types…. some are phagocytic and others arent

1. increase WBCs
   + infection, leukaemia, malignancies, stress
2. low level of WBCs
   + malaria

Question 6

what are the 3 process of the immune response

Answer 6

1. body identifies a substance or antigen and determines if its foreign or not…
2. if the substance is foreign, the body reacts by producing antibodies or anti-toxins
3. body produces memory cells so that if it encounters the antigen again it can react more quickly

Question 7

what are the 2 types of immunity and what do they produce

Answer 7

1. Humoral: antibodies

2. Cell Mediates: anti-toxins

Question 8

which organ is the largest unit of the RE system

Answer 8

spleen

Question 9

when during fetal development does the spleen develop (wks) and from which cells

Answer 9

• 5 wks

- from mesoderm

Question 10

when during fetal development (wks) does the spleen start performing hematopoietic function and when does it assume and adult function

Answer 10

• 11 wks (stops shortly after birth)

- at 5th of 6th month gestation

Question 11

which area of the spleen is not covered by peritoneum

Answer 11

hilum

Question 12

where in the body is the spleen located… which ligaments hold it in place

Answer 12

-left hypochondrium/LUQ

+ gastrosplenic, splenorenal, phrenocolic ligaments

Question 13

whats the relationship of the spleen to the diaphragm

Answer 13

superior, lateral, posterior

Question 14

the spleen sits medial to which structures

Answer 14

stomach, panc tail, splenic flexure, L kidney

Question 15

the spleen sits anteior to which structures

Answer 15

stomach

Question 16

what are the norm measurements of the spleen for an adult

how do we assess the size of a child spleen

Answer 16

L: up to 12 cm
W: 7-8 cm
H/AP: 3-4 cm

-formula until age 21

Question 17

what are the 3 categories of splenic size?

Answer 17

Norm: up to 12 cm
Moderate splenomegaly: 13-18 cm
Severe splenomegaly: over 18 cm

Question 18

when would the spleen appear enlarged

Answer 18

• in decube position (2 X size of kidney)

- is you see a flattened caudal kidney (reliable sign)

Question 19

does spleen size decrease with age

Answer 19

yes

Question 20

which vessels coverage to form the splenic vein

Answer 20

many smaller spleen veins @ the splenic hilum

Question 21

how many arteries does the splenic artery branch into at the hilum

Answer 21

6

Question 22

the splenic vessels course through which ligament

Answer 22

splenorenal

Question 23

how can the removal of the spleen in childhood effect the body

Answer 23

can impair immune response

Question 24

describe the microscopic anatomy of the spleen

Answer 24

-divided into lobules via projections of the c-tissue capsule

Question 25

the lobules of the spleen contain what 2 pulp types? | describe the 2 types

Answer 25

1. Red pulp + venous component + mesh network of splenic sinuses alternating with splenic cords 2. White pulp + sm islands of lymphatic tissue that contain large lymphocytes and macrophages

Question 26

what does the the lymphatic tissue in the white pulp produce whats another term for the lymphatic tissue in the white pulp

Answer 26

antibodies Malpighian corpuscles

Question 27

the sinusoids of the red pulp are lined with what cells? whats another term for the splenic cords in the red pulp

Answer 27

phagocytic cells -called Cords of Billroth

Question 28

what are the RE functions of the spleen

Answer 28

- produce lymphocytes and plasma cells (antibodies) | - storage for iron and metabolites

Question 29

what are the organs specific functions of the spleen

Answer 29

- Primary function: + filter blood -act as blood reservoir, stored 50-1000 ml -erythropoiesis/hematopoiese in the fetus + spleen will retain this ability but bone marrow does it after birth

Question 30

what are the 2 components of blood filtration carried out in the spleen

Answer 30

Culling and pitting

Question 31

which 2 windows can be used to scan the spleen

Answer 31

intercostal and subcostal (patient can be supine, RPO or decube)

Question 32

what are we assess when scanning the spleen

Answer 32

size position focal abnormalities surrounding fluid collections (cause by injury)

Question 33

spleen can be used as a window to assess what organs

Answer 33

L kidney and panc tail

Question 34

describe the echogenicity and echo texture of the spleen

Answer 34

texture: homogenous w/ low to medium level echos echogenicity: - more echogenic then L kidney cortex - isoechoic or slightly more echogenic than the liver

Question 35

what shape will the spleen have if enlarged

Answer 35

1/2 moon shape instead of crescent

Question 36

what are 2 scanning pitfalls when scanning the spleen

Answer 36

1. pseudoperisplenic leison + when the L lobe of the liver is seen superior to the spleen... mimics hematoma or abscess + occurs in thin patients and kids 2. Fluid filled stomach or tail of panc mistaken for mass

Question 37

what are accessory spleens/splenules/splenuculi

Answer 37

- sm collection of splenic tissue near the hilum... often < 1 cm

Question 38

what is a born again spleen

Answer 38

hypertrophy of an accessory spleen or other splenic tissue post splenectomy

Question 39

what is a hematocrit what do low levels indicate

Answer 39

- lab test that gives the % of RBCs per volume of blood | - indicates hemorrhage or internal bleeding

Question 40

what is a hemoglobin lab test what do low levels indicate

Answer 40

- hemoglobin is a protein in RBCs that transport 02 | - indicates blood loss, anemia, leukemia, or can mean that the spleen isn't functioning properly

Question 41

what is thrombocytopenia... what can cause it

Answer 41

- low platelet count | - internal bleeding, leukemia, Vit B 12 deficiency

Question 42

what is thrombocytosis... what can cause it

Answer 42

- increased levels | - hemorrhage, infectious disorders

Question 43

what other typing of DI are used to image the spleen.. what tests do they do

Answer 43

1. nuch med + RBC scan/Scintography - radioactive tracer is injected into the blood... used to assess morphology/volume of spleen 2. CT