Anatomy Lecture 12

  1. Lymphoid Organs (lymph nodes,thymus, spleen):
    • diffuse lymphatic tissue and lymphatic follicles or nodules
    • enclosed by a connective tissue capsule
  2. Lymph Nodes:
    • location
    • function
    • structure:
    • shape and size
    • cortex: follicles (nodules) with germinal centers
    • medulla: diffuse tissue continuation of the cortex, contains B cells and plasma cells
    • sinuses:
    • subcapsular sinus: reticular connective tissue, macrophages, dendritic cells
  3. lecture notes
    • between 1-25mm
    • covered in a fibrous capsule that projects inwards forming trabeculae
    • all out going vessels connect at the hilum of the lymph node
    • subcapsular space: mesh work of reticular fibres macrophages and dendritic cells (contain antigens)
    • outer cortex: contains b cells with geminal centers
    • deep cortex: where lymphocytes enter (dominated by t cells)
    • medulla: contains b cells and plasmocytes aranges in lines call medullary cords
    • 99% of antigens removed
    • fixed macrophages line the walls of lymphatic sinuses
  4. circulation within and through a lymph node:
    • afferent lymphatics
    • efferent lymphatics
    • hilus
  5. Thymus:
    • location: posterior to the manubrium of the sternum (also in superior pleural cavity)
    • function
    • structure: divided into 2 lobes via the septa formed by the capsule
    • thymic lobules: (2mm in width)
    • cortex (stem cells, T cells)
    • medulla (T cells)
    • Hassall’s corpuscles
  6. lecture notes
    • involution: the degeneration of the thymus with age
    • cortex: stem cells develop and divide into t cells that then migrate into the medulla
    • Medulla: thymic hormones differentiate t cells
    • hassals corpuscle: clumps of t cells
    • thymic capillaries: like in the CNS they dont permit crossing thus making a blood thymus barrier
  7. Spleen:
    • location
    • function
    • structure:
    • surfaces: diaphragmatic (smooth and convex), visceral (large bumpy surface), gastric (contains indentations), renal (long and flat edge)
    • hilus: in the middle, entrance of all efferent vessels
    • white pulp: T and B cells
    • red pulp: reticular connective tissue , red blood cells, macrophages, lymphocytes, venous sinuses, splenic cords
  8. lecture notes
    • 12 cm and 160 g
    • location: curving lateral border of tomach, between 9 and 11th rib on the left side and is attatched to the stomach by the gastrosplenic ligament
    • Function: removes abnormal cells via phagocytosis, stores iron from broken down red blood cells, initiates immune response from antigens
    • red pulp: lots of RBCs
    • white pulp: lymphoid nodules formed in the spleen
Card Set
Anatomy Lecture 12