Immune System Flashcards
primary lymphoid organs
thymus
bone marrow
secondary lymphoid organs
lymph nodes
spleen
various lymphoid mucosal tissues
superficial lymph nodes
cervical
axillary
inguinal
deep lymph nodes
tracheal
aortic
innate defences
physical barriers
phagocytes
immune surveillance
interferons
complement
inflammation
fever
immune cell development in red bone marrow
hemocytoblasts: immune stem cells
series of differentiation and migration
formation of mature NK cells and B cells
formation of T cell stem cells
immune cell development in the thymus
stem cells from bone marrow differentiate in response to thymic hormones
forms T cells
which immune cells are granulocytes vs agranulocytes
granulocytes: neutrophils, eosinophils, basophils
agranulocytes: lymphocytes, monocytes
neutrophils
nucleus
granules
proportion of immune cells
lifespan
role
nucleus: 3-5 lobes
granules: faint/light pink
proportion of immune cells: 50-70%
lifespan: 1-4 days
role: kill and phagocytose bacteria
eosinophils
nucleus
granules
proportion of immune cells
lifespan
role
nucleus: bilobed
granules: red/dark pink
proportion of immune cells: 1-4%
lifespan: several months
role: kill parasites and modulate local inflammation
basophils
nucleus
granules
proportion of immune cells
lifespan
role
nucleus: bilobed or S-shaped
granules: dark blue/purple
proportion of immune cells: 1%
lifespan: several months
role: modulate inflammation, histamine during allergy
lymphocytes
nucleus
granules
proportion of immune cells
lifespan
role
nucleus: large and spherical
granules: none
proportion of immune cells: 20-40%
lifespan: hours to many years
role: adaptive immunity
monocytes
nucleus
granules
proportion of immune cells
lifespan
role
nucleus: C (kidney) shaped
granules: none
proportion of immune cells: 2-8%
lifespan: hours to years
role: precursors of macrophages and mononuclear phagocytic cells
roles of IL1-6
IL-1: Fever
IL-2: T-cell stimulator
IL-3: Marrow stimulator
IL-4: IgE stimulator
IL-5: Class switching to IgA
IL-6: Stimulates acute phase protein
Proinflammatory
Potentially drives COVID-19
symptoms
why does the type of infection causing pneumonia change the colour of lung histology
due to different immune cells present
can be used to identify the source of pneumonia by biopsy histology
why do fungi remain in the lung
cells are large and hard to remove
pitting oedema
causes
treatment
palpation leaves imprint, often in extremities
caused by heart failure (causing fluid build up in legs) and impaired kidney function (causing fluid retention)
NOT related to lymphatics
treated with frusemide - diuretic
lymphoedema
causes
primary vs secondary
treatment
non-pitting oedema due to blocking of lymph channels
chronic accumulation of fluid in soft tissues
primary: inherited mutation alters lymphatic development
secondary: result of obstruction or damage
treatment: skincare, exercise, elevation, compression, decongestive therapy, surgery
MHC class I
cells
structure
role
cells: all nucleated cells
structure: alpha subunit and B2 microglobulin
role: present self antigens to NK cells
tumour and virus-infected cells lack MHC I
recognised by CD8 cells
MHC class II
cells
structure
role
cells: macrophages, dendritic cells and B cells
structure: two alpha subunits
role: recognised by CD4 cells leading
leads to clones, CD8 and B cell activation
stroma of the thymus
epithelial cells in crypts - maturation site of T cells
provide physical and chemical environment for T-cell maturation
involution of the thymus
atrophy with age leading to reduction of immunity
starts after puberty
regions of the thymus and their roles
cortex: where lymphocytes originate
medulla: where selective clonal deletion occurs
outer capsule
Di George syndrome
thymic aplasia (incomplete or absent development)
causes susceptibility to viruses and fungi
