Exam 3 Flashcards
Mast cells
Highly granulated tissue resident cells containing surface expressed FC-epsilon receptor I. Found in mucosa in connective tissue, responsible for maintaining integrity of tissue and altering the immune system of localized trauma.
• cross bound to IgE
Eosinophils
Tissue resident granulocytes that stain heavily with eosin, Principal cause: Id airway damage, chronic asthma 
Basophils
Least numerous of all granulocytes. Secrete Th2 polarizing cytokines, IL-4, IL-13 which stimulate IgE 
Type I hypersensitivity: immediate
• IgE, Th2 cells
• mast cells, eosinophils, basophils, and their mediators (lipid, cytokine, etc)
• wheal and flare response
• atopy: predisposition to IgE mediated sensitization
• Pollen, food, venom, drugs
Type II Hypersensitivity: antibody mediated
• IgM, IgG, against cell surface ECM antigens
• opsonization and phagocytosis
• Complement and FC receptor mediated recruitment and activation of leukocytes (neutrophils, macrophages)
• abnormal cell function (neuro blockade) 
Type III hypersensitivity: Immune complex mediated
• immune complex is circulating antigens
• IgM, IgG
• Complement and FC receptor mediated recruitment an activation of leukocytes
Type IV hypersensitivity: T-cell mediated
• CD4+ T cells (Th1, Th17)
• Cytokine mediated inflammation and macrophage activation
• CD8+ CTLs
• Direct target cell killing, cytokine-mediated inflammation
Immediate hypersensitivity
Allergen + B cell —> presents to Th2 cell —> makes memory cell + plasma cell —> sensitizes mast cell —> allergen re-presented —> granulocyte response
Contents of mast cell granules 
Enzyme: tryptase, chymase, cathepsin G, carboxypeptidase
Toxic mediator: heparin, histamine
Cytokine: TNF-alpha 
Prevention of hypersensitivity I
Desensitization: Serial application of allergens in gradually escalating doses
Anti-IgE antibodies: expensive, not worth 
Examples of type II hypersensitivities
• Goodpasture’s syndrome
• Graves’ disease
• Myasthenia gravis
• Erythroblastosis fetalis
Immune complexes (type III)
• formed between antibody and antigen, get deposited in tissues
• ICs Result from: persistent infection, inhalation, auto immune disease, cryo-globulins
Diseases that result from type III hypersensitivities
Auto immune diseases: SLE, rheumatoid arthritis, multiple sclerosis
Drug allergies: penicillin and sulfonamides, serum sickness
Infectious diseases: post streptococcal, glomerulonephritis, meningitis, hepatitis, mononucleosis
T cell mediated inflammatory response (CD4+, type IV)
• most destructive, requires antigen specific effector T cells to activate macrophages (Th1)
• Antigen presenting cells: macrophages, Langerhans cells
Contact hypersensitivity (Type IV)
• Eczematous skin reaction
• Nickel, rubber, dyes, fragrance, plants
• Haptens: Small sensitizing agents that penetrate skin (help bind self-peptide to MHC class II making it immunogenic)
Dinitrochlorobenzene (DNCB)
Hapten from plants that sensitizes nearly everyone (poison ivy/oak/sumac) 
Granulomatous hypersensitivity
• tuberculin — TB test is an example of type IV hypersensitivity
• also leprosy, Crohn’s, schistosomiasis, and Sarcoidosis 
• persistence of antigen within macrophages due to killing mechanisms being blocked or particles that the cells cannot destroy
Multi nucleated giant cells
Macrophage —> epithelium’s cells
• cells that lose many functions such as mitochondria and ER, but produce a lot of TNF-alpha to continue hypersensitivity response (chronic Th1 activation)
Contact dermatitis cytokine responses
— IL-2
— IL-8
— IFN- gamma
— GM- CSF
Haptens
• Highly soluble, highly reactive, bind covalently and non-specifically to skin proteins which activates Th1 cells, CD4+ T cells in the skin (type IV)
• your hands can spread these in linear patterns and to your eyes (wherever you touch)
Pentadecacatehol
A common hapten, found in poisonous plants
Treating contact dermatitis
Corticosteroids: block the transcription of pro-inflammatory genes, and up regulate the production of inhibitors of pro-inflammatory transcription factors (Immunosuppressive)
Antihistamines: help with itching, block histamine receptors on mast cells to reduce histamine release, does not improve rash
Poison ivy
• appearance of rash two days after exposure (must be 2nd exposure at least)
• Red, raised blistering lesions of contact dermatitis
• Infiltration of blood cells into the tissue at the site of contact with the Hapten
• Death of local tissue cells, destruction of ECM = blisters 
Contact dermatitis and Th1 T cells
1.) antigen is injected into subcutaneous tissue and processed by local antigen presenting cells
2.) A Th1 effector cell recognizes antigen and releases cytokines that act on vascular endothelium 
3.) recruitment of phagocytes and plasma to the site of antigen injection causes a visible lesion
Outcomes of CD4 T cells engaging with Hapten in the periphery
1.) IFN-gamma
2.) TNF-alpha and/or LT
3.) chemokines
4.) IL-3 and/or GM-CSF
IFN-gamma
Induces expression of vascular adhesion molecules. Activate macrophages, increasing release of inflammatory mediators
TNF-alpha and/or LT
Local tissue destruction. Increased expression of adhesion molecules on local blood vessels
Chemokines
Macrophage recruitment to site of antigen
IL-3 and/or GM-CSF
Monocyte production by bone marrow stem cells
Direct Coomb’s test (positive)
1.) blood sample from a patient with immune mediated hemolytic anemia: antibodies on RBC surface
2.) The patient RBCs are washed and incubated with anti-human antibodies (Coombs reagent)
3.) RBCs agglutinate, Anti-human antibodies form links between RBCs by binding to the human antibodies
• Looking for the antibody on the cell in the donor
Indirect coombs test (positive)
1.) recipients serum is obtained, containing antibodies
2.) Donors blood sample is added to the tube with serum
3.) Recipients antibodies that target the donors RBCs form antibody antigen complexes
4.) Anti-human antibodies are added to the solution (Coombs reagent)
5.) Agglutination of RBCs occurs, because human antibodies are attached to red blood cells
• Looking for antibody in recipient for what donor has

Gastrulation layers
Ectoderm: epidermis, CNS
Mesoderm: musculoskeletal, cardiovascular, urogenital
Endoderm: lining of G.I. tract and respiratory tract
Gastrulation layer descriptors
Endoderm: Cuboidal epithelium
Ectoderm: columnar epithelium
Mesoderm: mesenchyme (multipotent)
Notochord and neural tube
• overlaid by ectoderm
• Signals the overlying ectoderm to thicken and old, folds come together to form neural tube
• Incomplete closure of neural tube leads to anencephaly
Neural crest
• arise from ectoderm
• Multipotent cells at the border of the neural plate
• Contribute to PNS, craniofacial cartilage, melanocytes, endocrine cells, glia
Mesoderm
• mesenchyme, Embryologic connective tissue
• divides into:
—Paraxial mesoderm (Somites)
—intermediate mesoderm (urogenital)
— Lateral plate mesoderm (parietal and visceral)
Somites
• mesenchymal tissue derived from Paraxial mesoderm
• Cranial most somites are called somitomeres and contribute to the head
• Sclerotome, myotome, dermatome
Epaxial
Skeleton muscle innervated by dorsal rami of the spinal nerve
— Intrinsic back muscles
Hypaxial
Skeletal muscle innervated by ventral rami of spinal nerve
— Abdomen, superficial back
Lateral plate mesoderm
1.) parietal (somatic) mesoderm : adheres overlying ectoderm, body wall including limb buds
2.) Visceral (splanchnic) mesoderm : Adheres to underlying endoderm, muscular wall of the gut, circulatory system
 apical ectodermal ridge
• proliferation of mesenchymal cells in the progress zone
• Key for limb development, without limbs do not form
Progress zone
• site of proliferation of Limb bud
• Proximal to distal growth pattern
Zone of polarizing activity (ZPA)
• Key for Anteroposterior patterning (medial lateral in the adult)
Limb buds are influenced by what?
• HOX genes
• Aer signals for proximodistal development (stylopod, zeugopod, autopod)
• Dorsal and ventral ectoderm specifying the dorsoventral patterning
• ZPA causes the expression of SHH genes to control anteroposterior patterning
Amelia
Absent Limb
Meromelia
Partial absence of limb
Hemimelia
Absence of the fibula
Phocomelia
Reduced/shortened limb
Talipes equinovarus
Club foot, sole is turned mediately, foot is inverted
Digit formation
- AER is responsible for proximal distal patterning
2. ZPA is responsible for anteroposterior patterning (Shh, asymmetry in the 5 fingers— thumb has none, pinky has a lot)
Polydactyly
Born with extra digits, can be soft tissue only, soft tissue and bone, skin and soft tissue and multiple bones
(most commonly on the pinky side)
Syndactyly
Failure of intra-digit apoptosis resulting in fused digits after birth
(Simple, complex, complicated)
Limb rotation
• explains the dermatome pattern on adults
• Upper limbs are externally/laterally rotated— dorsal elbows
• Lower limbs are internally/medially rotated— ventral knees
Bone formation
1.) Endochondral ossification (most common) — Cartilaginous precursor model becomes bone
2.) Intramembranous ossification — Bone forms within membrane sheaths (skull, clavicle)
Endochondral ossification
1.) cartilaginous model: chondrocytes create new cartilage
2.) Cartilaginous model is replaced by bone: osteoblasts create new bone
3.)  Bone growth occurs at the epiphysis of primary and secondary ossification centers
Diaphysis
Bone shaft
Epiphysis
Bone growth plate
Fibrous joints
- Sutures: connect cranial bones
- Gomphoses: Connect teeth to alveolus
- Syndesmosis: slightly mobile such as radius and ulna connection
Cartilaginous joints
— Hyaline or fibrocartilage
- Synchondrosis: Hyaline cartilage, epiphyses
- Symphyses: Either Hyaline or fibrocartilage: pubic symphysis
Synovial joints
Mobile joints characterized by a joint capsule filled with synovial fluid
— Joint capsule is fibrous connective tissue
— Articular cartilage is Hyaline
Types of synovial joints
Planar: acromioclavicular
Hinge: elbow
Pivot: atlantoaxial
Condyloid: metacarpophalangeal
Saddle: thumb CMC1
Ball and socket: hip, shoulder
Congenital infantile hyperpituitarism
Gigantism: excessive growth hormone, increased height before Epiphyseal seal
Acromegaly: excessive growth hormone after epiphyseal fusion, affects shape and morphology of phones and soft tissue
Skeletal system
Axial skeleton: Skull, Vertebral column, ribs, sternum
Appendicular skeleton: pectoral and pelvic girdles, limbs
Intravertebral disc development
• Notochord becomes the nucleus pulposus
• sclerotome becomes annulus fibrosus
Spina bifida
— Failure of the halves of the embryonic cartilaginous neural arch to fuse
1.) Occulta: occurs at the L5 or S1 vertebrae. Minor form can produce no symptoms or minor symptoms (tuft of hair or small dimple at lower back)
2.) Cystica: protrusion of spinal cord and or meninges — Including meningocele (CSF, meninges), and myelomeningocele (spinal nerves/cord/roots)
Klippel-Feil Syndrome (Brevicollis)
• congenital effusion of cervical vertebral bodies
• Restricted neck movement
• Smaller cervical nerve roots
Congenital scoliosis
Results from lack of an ossification center, incorrect segment, or vertebral fusion 
 Development of the ribs
• come from mesenchymal costal processes of the thoracic vertebrae
• Begin as cartilaginous and then ossify
• Site of union of the costal process with the vertebra is replaced by costovertebral synovial joint
Development of the sternum
• Sternal bars: vertical mesenchymal bands
• Convocation occurs as these bars move medially and then fuse
• Cartilaginous models of the manubrium, sternebrae, and xiphoid process
Cervical ribs
Usually rudimentary, development of the costal processes of the cervical vertebrae, usually attached to the seventh cervical vertebrae as tiny nubs
Thoracic outlet syndrome
Compression due to the narrowing of the superior (cranial) opening of the thoracic cage from cervical ribs
Lumbar ribs
Development of the costal processes of the lumbar vertebrae, usually attached to the first lumbar vertebrae, benign
Sternal foramen
Varies in size, results from incomplete fusion of the cartilaginous sternal bars during development (looks like a gunshot wound) 
Pectus excavatum
Concave depression in the lower sternum, pushes on lungs and heart
Muscle development
1.) skeletal as you grow
2.) Smooth, from splanchnic mesenchyme surrounding the primordial gut
3.) cardiac, from lateral splanchnic Mesoderm, forms the conduction system of the heart: Purkinje fibers
Poland syndrome
Absence of pectoralis major and minor, ipsilateral breast hypoplasia, absence of 2-4 ribs, occasionally absent mammary gland
Torticollis
— Wryneck
— Shortened fibers of sternal cleidomastoid muscle
— Lateral bending of the head to the affected side and slight turning away from the side of the shortened muscle
Acne vulgaris
Inflammatory disease of the pilosebaceous unit
Comedones
Baseline of acne, small solid bumps