Lymphatic histology Flashcards
function of the lymphatic system
- vessels transport excess fluid away from interstitial space in most tissues and return it to the bloodstream
- special lymphatic capillaries (lacteals) located in the lining of the small intestine absorb digested fats, then transport the fats to venous circulation
- organs of the lymphatic system also help defend the body against infection by disease-causing agents
components of the lymphatic system
lymphatic capillaries
lymphatic vessels
lymphatic trunks
lymphatic ducts
label top to bottom
lymph duct
lymph trunk
lymph node
collecting lymphatic vessels with valves
lymphatic capillary
what is in the image
lymphatic capillary
what do lymphatic capillaries have
epithelial lining
single layer of endothelial cells
function of anchoring filament
pulls apart endothelial cells to widen the opening
label the image top to bottom
interstitial fluid
tissue cell
anchoring filament
opening
endothelium of lymphatic capillary
lymph
what causes lymph to be transported through lymphatic vessels
- bulging of contracting skeletal muscles and pulsation of nearby arteries
- contraction of tunica media
- normal movement of the limbs and the trunk
types of lymphoid cells
B cells
T cells
NK cells
Plasma cells
Dendritic cells and macrophages
B cells
develop in the bone marrow
responsible for production of antibodies
B cells differentiate into B memory cells and plasma cells
providing humoral immunity
T cells
originate in the bone marrow
mature in the thymus
subsequently seed into secondary lymphoid tissue
differentiate into helper, memory and cytotoxic
cell mediated response
assist B cells in humoral
NK cells
arise from bone marrow
stimulated by interferon
recognise and destroy non-self cells
plasma cells
differentiate from B lymphocytes and produce humoral antibodies
dendritic cells and macrophages
phagocytose foreign matter
enhance bodys repsonse to antigen by presenting antigen to lymphocytes and secrete immunomodulatory factors
label the lymph node
lymphatic nodule: purple
germinal centre: pink
mantle zone: border of purple
medullary sinus: bit after the beige
medullary cord: beige bit
paracortex: blue bit
afferent vessels: several green bits
high endothelial venule: blue swollen bit
hilum: outside
efferent vessel: one fatter green bit
capsule: the thicker wall
valve: valve looking structure
what is the cortex comprised of
lymphatic nodule
germinal centre
mantle zone
what is the medulla comprised of
medullary sinus
medullary cord
cortex function
B cell activation and clonal expansion
produce large number of B lymphocytes reactive to specific antigens
production of memory B lymphocytes
paracortex function
T cell activation
clonal expansion to produce large numbers of t lymphocytes reactive to pseicifc antigens
production of memory T lymphocytes
medulla function
plasma cell maturation and secretion of antibody
high endothelial venules
located in the lymph nodes, appendix, tonsils,peyers patches
lining is simple cuboidal
allows diapedesis
diapedesis
allows transport of lymphocytes through the endothelium
label the lymph node
co- cortex which has lymphoid nodules
me- medulla (plasma cells and macrophages)
ca-capsule
label the lymph node
ca- capsule
ScS- subscapular sinus
GC- germinal center
Pc- paracortex
LV- lymph vessel
V- valve
BV- blood vessel
what is the function of the sub scapular sinus
receives lymph and allows transportation
clinical correlation of lymph nodes
sentinel lymph node
hypothetical first lymph node or group of nodes draining a cancer
what is in the image? where is it located? what is its function?
Hassal/thymic corpuscle
in the thymic medulla
composed of type 6 epithelial reticular cells ERC
ERCs are primary cells involved with making sure no T cells are allowed to survive
could attack body’s own cells
CATCH 22
C- congenital heart disease
A- abdnomal face
T- thymic aplasia or hypoplasia
C- cleft palate
H- hypocalcemia
22: microdeletion of chromosome 22q11
spleen location
left upper quadrant
inferior to diaphragm
in area of rib 9 and 10
posterior to the stomach
intraperitoneal
label spleen
LHS:
splenic artery
splenic vein
RHS:
marginal zone (white pulp)
periarteriolar lymphoid sheath (white pulp)
primary follicle (white pulp)
red pulp
thymus location
inferior to the neck
in the superior thorax
posterior to the sternum
2 lobes, have numerous lobules
describe the image
blood-thymus barrier prevents pre-mature exposure of lymphocytes to antigens
basal lamina of reticular cells often fused with basal lamina of capillary endothelium, create physical barrier that protects immature lymphocytes from foreign blood-borne antigens
white pulp
composed mostly of B lymphocytes and periarterial lymphatic sheath PALS
sleeve of T lymphocytes that surrounds a central arteriole
red pulp
composed mostly of splenic cords
suspended in loose reticular connective tissue, contains B and T lymphocytes
cords are surrounded by splenic sinuses lined by endothelial cells
surrounded by reticular fibres
thin fibrous capsule in spleen
trabeculae extend inwards
ratio white pulp
20%
composed of lymphoid tissue
provides spleen its immune function
ratio red pulp
80%
splenic sinuses (vascular channels)
splenic cords
provides macrophages to phagocytose defective blood cells
label spleen
RP- red pulp
WP- white pulp
what is in the image? label it? what type of lymphoid tissue?
palatine tonsil
F: lymphoid follicle beneath epithelium
C: stratified squamous epithelium folded into crypts
is GALT
