Histology Block Ii

Front 1

IgG

Back 1

Major Ig in secondary immune responses.
80% of circulating Igs

Front 2

IgD

Back 2

B cell surface marker

Front 3

IgM

Back 3

First Ig to increase during an immune response.
Present on surface of B cells.

Front 4

IgA

Back 4

The secretory immunoglobin.
Present in bodily secretions.

Front 5

IgE

Back 5

Present on surface of mast cells and basophils (immediate hypersensitivity reaction)

Front 6

CD2

Back 6

T Cells

Front 7

CD4

Back 7

Helper T Cells

Front 8

CD8

Back 8

Cytotoxic T Cells

Front 9

CD9

Back 9

B Cells

Front 10

Interleukins

Back 10

Cytokines that interact with leukocytes

Front 11

APCs

Back 11

Dendritic cells
Follicular dendritic cells
Macrophages
B Lymphocytes
M cells in Peyer's Patches

Front 12

Dendritic Cells

Back 12

APCs.
Capture and process antigens
Abundant in T cell areas of lymphoid organs

Front 13

Follicular dendritic cells

Back 13

Present in lymphoid nodules.
Trap antigens on surface for interaction w/ B cells.
Do not endocytose or process antigens.

Front 14

Cytotoxic T cells

Back 14

Act over short distances.
TCRs.
Always require T-helper cells.
Act by producing perforins and fragmentins.

Front 15

B Cells (Plasma Cells)

Back 15

Act over long distances.
SIGs.
Usually require T-helper cells.
Act by producing Abs

Front 16

Allergic reaction

Back 16

An attempt to neutralize the effects of an antigen

Front 17

Immunodeficiency

Back 17

A defect in either the innate or adaptive immune systems

Front 18

Autoimmune disease

Back 18

T lymphocytes that attack self antigens

Front 19

Immediate Hypersensitivity

Back 19

An immediate immune reaction within minutes of an antigen and antibody, bound to mast cells, w/ degranulation, occurring in sensitized individuals.

Front 20

Where is the site of atherosclerotic plaque formation?

Back 20

Tunica intima

Front 21

What is diagnostic of elastic arteries?

Back 21

Tunica media has 40-70 lamella of elastic tissue that absorb systolic pressure

Front 22

What is diagnostic of muscular arteries?

Back 22

Tunica media has >40 layers of smooth muscle.

Front 23

Arterioles

Back 23

Show only one or two smooth muscle layers in the tunica media

Front 24

What fibers are contained within capillary endothelium? And what do they do?

Back 24

Desmin or vimentin - lend structural support.

Front 25

Pericytes

Back 25

Well-developed cells of mesenchymal origin; surround capillaries at various sites; ability to differentiate into smooth muscle cells following injury to endothelium.
Contain proteins with contractile capabilities: tropomyosin, isomyosin.

Front 26

Continuous capillary

Back 26

Characterized by continuity of endothelial cell. Found in all muscle, nervous tissue, CT, glands. Transports substances in bidirectional pathways (pinocytosis; transcytosis)

Front 27

What is diagnostic of large veins?

Back 27

Tunica media is thin with only a thin layer of circular smooth muscle.
Tunica adventitia is thick and contains elastic and collagenous network. Also contains broad bundles of smooth muscle cells arranged longitudinally.

Front 28

Classification of lymphoids

Back 28

Primary: sites where lymphocytes are programmed to be immunocompetent cells
Secondary: sites where immunocompetent cells respond to antigens

Front 29

Thymus

Back 29

Location where T cells become immunocompetent.
No reticular fibers.
Cortex and medulla. No lymph nodules.
Epithelioreticular cells allow for maturation of lymphocytes in antigen-free environment.
Hassall's corpuscles in medulla.

Front 30

What is diagnostic of thymus?

Back 30

Thymic corpuscles in medulla

Front 31

Hormones that affect T-cell maturation in thymus

Back 31

Thymosin, thymopoitin, thymolin, thymic humoral factor: affect development of T-cells.
Glucocorticoids: decrease T cell numbers.
Growth hormone: increases T cell numbers.
Sex steroids: cause involution of gland

Front 32

DiGeorge

Back 32

Thymic hypoplasia d/t failure of development of third and fourth pharyngeal pouches. Produces variable loss of T-cell immunity.
Will also lose parathyroid.

Front 33

What is diagnostic of lymphatics?

Back 33

No tunics

Front 34

Lacteals

Back 34

lymphatic capillaries in villi of small intestine

Front 35

Structure of lymph nodes

Back 35

Oval or kidney-shaped w/ hilum.
reticular cells and fibers in stroma.
cortex: lymphoid nodules (B-cells)
deep cortex: T-cells, high endothelial venules
medulla: medullary cords. Sinusoids have reticulum across them

Front 36

What is diagnostic of spleen?

Back 36

Central arterioles offset to GC in white pulp w/ periarterial lymphatic sheaths

Front 37

What occurs in the white pulp?

Back 37

Lymphocyte proliferation (T and B)
APCs
AB production
Remove blood macromolecular antigens

Front 38

What occurs in red pulp?

Back 38

Filtration!

Front 39

Ground substance of bone

Back 39

Proteoglycans/GAG complex, eg Chondroitin 4-sulfate for compressive strength.
Glyoproteins - for attachment of bone cells and fibers to the mineralized ground substance.
Growth factors, eg BMP induce differentiation of mesenchymal cells into osteoblasts

Front 40

Osteonectin

Back 40

Multiadhesive proteins in ground substance of bone

Front 41

Osteocalcin

Back 41

Binds Ca++ and raises their local concentration
Ground substance of bone

Front 42

Bone fibers

Back 42

Primarily collagen type I. Secreted by osteoblasts. Like rebar

Front 43

Osteoprogenitor cells to osteoblasts

Back 43

Triggered by core binding transcription factor alpha-1, osteoprogenitor cells give rise to osteoblasts

Front 44

Alkaline phosphatase

Back 44

Secreted by osteoblasts. IMPORTANT!!! Responsible for calcification of bone.

Front 45

Howship lacuna

Back 45

Aka resorption bay. Depression formed by osteoclasts where bone has eroded

Front 46

How do osteoclasts degrade bone?

Back 46

1. Pump H+ protons from membrane into resorption site to create an acidic environment for dissolving hydroxyapatite.
2. Howship lacuna also receive hydrolytic enzymes in the form of lysosomal hydrolases promoting organic matrix resorption. All ions and matrix products are reused

Front 47

What controls osteoclast activity?

Back 47

Osteoblastic cytokine and by hormones (parathormone and thyocalcitonin).
Osteoclasts have no receptor for parathormone, thus it functions through osteoblasts, which secrete OSF.

Front 48

Intramembranous bone formation

Back 48

Produced by differentiation of mesenchymal cells. begins 8th week of development.
Found in flat bones and "bone collars" of long bones.
Occurs by appositional growth.

Front 49

Endochondral bone formation

Back 49

Vascularized mesenchyme which becomes cartilage model is precursor.
Formed in places of demand for weight bearing.
Periosteal bone collar forms around diaphysis, then cartilage calcifies. Crucial step! Alk phos is released upon hypertrophy, allowing for calcification.
Appositional growth from perichondrium to increase width. Interstitial growth to increase length.

Front 50

Five zones of epiphyseal cartilage in developing endochondral bone

Back 50

1. Resting zone: hyaline cartilage
2. Proliferative zone: chondrocyte mitosis w/ cells stacked in columns in the long axis of the bone
3. Zone of hypertrophy: chondrocytes whose cytosol has an abundance of glycogen. Reabsorbed matrix is reduced to very thin septa.
4. Zone of calcified cartilage: death of chondrocytes produces a calcified cartilage matrix w/ hydroxyapatite crystals.
5. Zone of ossification: endochondral bone via osteoprogenitor cells form osteoblast which deposit woven bone over the calcified cartilage matrix.

Front 51

Synovial layer

Back 51

Specialized connective tissue: areolar/fibrous.
Mainly 2 types of cells that resemble:
1. Macrophages - type A synovocyte. bind, engulf and remove tissue debris
2. Fibroblasts - type B synovocyte. Synthesis of hyaluronic acid/GAG rich ground substance

Front 52

Fracture repair

Back 52

1. Torn blood vessel clots, producing large fx hematoma.
2. Gradually removed by macrophages and replaced by a soft procallus tissue rich in fibroblasts and collagen.
3. Fibrocartilagenous procallus is replaced by spicules of woven bone forming a hard callus throughout the original fx.
4. Woven bone is then remodeled as compact and trabecular/cancellous bone w/ fully functional vasculature.

Front 53

Osteomalacia

Back 53

Adult rickets. Soft bone d/t defective mineralization of bone matrix leading to reduction in calcium:organic matrix ratio

Front 54

Osteoporosis

Back 54

Decrease in bone mass d/t insufficient bone formation or increased bone resorption by osteoclasts

Front 55

Osteopetrosis

Back 55

Normal bone formation w/ absence of osteoclastic activity resulting in overgrowth and thickening of bone. Bones are hard but brittle.

Front 56

Osteitis deformans

Back 56

Aka Paget's Disease.
Replacement of normal bone by soft, poorly mineralized osteoid tissue accompanied by fibrosis.
pelvis is main bone affected.
enlargement of skull accompanied by bowing of femurs and tibias are diagnostic.

Front 57

Aortic dissection

Back 57

Separation of the tunica intima from tunica media.

Front 58

Aneurysm

Back 58

All 3 tunics are involved. No intimal flap.