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Clinical Morphology > Week 2 > Flashcards

Week 2 Flashcards

1
Q

First week after fertilization

A

1 layer. cleavage, blastocyst formation and implantation

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2
Q

ampulla

A

widened part of oviduct where the egg is fertilized

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3
Q

cleavage

A

Mitotic divisions of embryo without growth

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4
Q

blastomeres

A

cells of the cleaving embryo. they are totipotent until 4-8 cell stage

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5
Q

totipotent

A

capable of giving rise to both embryo and fetal contribution to placenta

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6
Q

morula

A

16 cell embryo

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7
Q

blastocyst (blastula)

A

the product after cavitation of the morula. cavitation is secretion of fluid to form a cavity

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8
Q

implantation

A

around day 6-10, the blastula attaches to the uterine wall

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9
Q

pluripotent

A

cells that can give rise to any type of cell in the body, but not the placenta

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10
Q

embryoblast

A

inner cell mass of the 6-day embryo that gives rise to the embryo

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11
Q

trophoblast

A

outer cell mass of 6-day embryo that gives rise to the fetal part of the placenta

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12
Q

week 2 after fertilization

A

2 layers (bilaminar). embyroblast and trophoblast differentiate into 2 laters each and formation of 2 cavities, amniotic and chorionic

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13
Q

epiblast

A

columnar cells that secrete fluid to form the amniotic cavity

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14
Q

hypoblast

A

cuboidal cells that line the blastocyst cavity converting it to the primitive yolk sac

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15
Q

syncytiotrophoblast

A

a layer of the trophoblast. One cytoplasm with many nuclei. The cells of the syncytiotrophoblast produce hCG

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16
Q

hCG

A

supports uterine lining and maintains pregnancy

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17
Q

lacunae

A

spaces in the syncytiotrophoblast. by 12 days they connect to capillaries in the uterine wall to establish placental blood supply

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18
Q

chorionic cavity

A

formed when spaces within the extraembryonic mesoderm join together.

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19
Q

extraembryonic mesoderm

A

loose connective tissue formed when hypoblast cells lining the primitive yolk sac proliferate

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20
Q

2 layers of the trophoblast that form during week 2

A

syncytiotrophoblast and cytotrophoblast

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21
Q

2 layers of the embryoblast that form during week 2

A

epiblast and hypoblast

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22
Q

yolk sac

A

blastocycst cavity lined with hypoblast cells

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23
Q

week 3 after fertilization

A

gastrulation establishes 3 germ layers (trilaminar): ectoderm, mesoderm and endoderm. Epiblast cells give rise to these germ layers while the hypoblast cells form the yolk sac

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24
Q

primitive streak

A

visible midline structure formed by migrating epiblast cells during the first invagination of the bilaminar embryo. Epiblast cells dive down and replace the hypoblast in this invagination

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25
Q

ectoderm forms

A

central and peripheral nervous system, epidermis, hair, nails, sensory epithelium of nose, ear, and eye

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26
Q

mesoderm forms

A

skeletal, smooth and cardiac muscle, cartilage, bone, connective tissue, blood, kidneys, and gonads

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27
Q

endoderm forms

A

epithelium of gut and its derivatives (liver, gallbladder, pancreas) and epithelium of respiratory system

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28
Q

neural tube

A

develops from ectoderm overlying the notochord(al process) and forms the nervous system

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29
Q

neural crest

A

cells on top of the neural tube that migrate away early in development and form the peripheral nervous system

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30
Q

notocord becomes

A

nucleus pulposis of the intervertebral discs

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31
Q

caudal regression syndrome (caudal dysplasia)

A

impairs the development of the lower half of the body. Can include lower limbs, lumbar and sacral vertebrae, lower gut, and urinary and genital tracts. Mechanism is abnormal gastrulation resulting in not enough caudal mesoderm. Some possible causes: maternal diabetes, wnt gene defects, vascular anomalies, and teratogens

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32
Q

sirenomelia (mermaid syndrome)

A

extreme and rare form of caudal dysplasia. Most obvious defect is a fusion of the 2 lower limbs at the midline

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33
Q

sacrococcygeal teratoma

A

a tumor that develops at the base of the coccyx due to abnormal gastrulation. A germ cell tumor thought to be derived from the primitive streak. Usually Nonmalignant, occur more often in females, and always require surgical removal

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34
Q

agenesis

A

intrinsic error in morphogenesis. missing organ cause by missing embryonic tissue (renal agenesis)

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35
Q

morphogenesis

A

process by which embryo takes shape

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36
Q

aplasia

A

intrinsic error in morphogenesis. missing organ due to growth failure of embryonic tissue (thymic aplasia)

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37
Q

hypoplasia

A

intrinsic error in morphogenesis. incomplete organ development (microcephaly)

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38
Q

malformation

A

intrinsic error in morphogenesis. abnormal development of a structure (neural tube defects, cleft lip or palate, congenital heart defects)

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39
Q

disruption

A

extrinsic error in mophogenesis. normal tissue growth arrested by external force. (amniotic band symdrome)

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40
Q

amniotic band syndrome

A

a “disruption” of morphogenesis. fibrous bands in amniotic cavity constrict growth of limbs or digits

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41
Q

deformation

A

extrinsic error in mophogenesis. abnormal growth (but not arrest) resulting in deformed or misshaped structures (potter sequence or symdrome)

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42
Q

potter syndrome

A

a “deformation” in morphogenesis occurring when fetus is exposed to decreased amniotic fluid so the face and libs are deformed due to lack of cushioing

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43
Q

period of maximal sensitivity

A

weeks 3 through 8 because organogenesis is occurring. Greatest risk for abnormal development due to exposure to teratogens.

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44
Q

“all or none” period

A

first 2 weeks after fertilization. Exposure to teratogens during this time will result in spontaneous abortion or have no effect

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45
Q

anomaly

A

a marked deviation from normal

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46
Q

association

A

nonrandom appearance of 2 or more anomalies together; cause not known

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47
Q

congenital

A

present at birth

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48
Q

syndrome

A

group of anomalies occurring together that has a specific common cause

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49
Q

sequence

A

primary anomaly itself resulting in additional defects

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50
Q

musculocutaneous nerve

A

terminal branch of the lateral cord and immediately enters the anterior compartment of the arm and runs between the brachialis and biceps brachii muscles

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51
Q

median nerve

A

terminal branch of the lateral and medial cords in the axilla and runs distally in association with the brachial artery in the medial aspect of the arm. It crosses anterior to the elbow joint and enters the forearm and continues into the hand through the carpal tunnel

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52
Q

anterior interosseous nerve

A

a deep branch of the median nerve in the upper parts of the forearm

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53
Q

ulnar nerve

A

terminal branch of the medial cord that runs distally in association with the brachial artery and median nerve in the medial aspect of the arm. It passes posterior to the medial epicondyle of the humerus and enters the forearm then travels down the medial aspect of the forearm close to the ulna and divides into superficial and deep branch at the wrist

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54
Q

axillary nerve

A

terminal branch of the posterior cord that exits through the posterior wall of the axilla and passes posterior to the surgical neck of the humerus

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55
Q

radial nerve

A

terminal branch of the posterior cord that passes out of the axilla into the posterior compartment of the arm in close association to the posterior aspect of the shaft of the humerus. It enters the forearm posterior to the lateral epicondyle of the humerus and travels to the posterior aspect of the hand

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56
Q

Posterior interosseous nerve

A

a deep branch of the radial nerve in the forearm

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57
Q

Atrophy

A

loss of a nerve to a muscle will result in atrophy disuse of that muscle

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58
Q

“weakness” of movement

A

a movement that is accomplished by 2 or more muscles innervated by different nerves will have weakness of movement if only one of the nerves is damaged

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59
Q

“loss” of movement

A

a movement accomplished by muscles all innervated by the same nerve will have loss of movement if that nerve is damages

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60
Q

loss of muscle function

A

nearly always results in the opposite function/motion being dominant

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61
Q

most common injury to the axillary nerve

A

anterior dislocation of the humerus or a fracture of the surgical neck of the humerus

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62
Q

most common injury to the radial nerve

A

midshaft fracture of humerus

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63
Q

common injury to median nerve

A

fractures of the elbow and distal humerus or within carpal tunnel (carpal tunnel syndrome)

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64
Q

injury of anterior interosseous nerve (deep branch of median nerve)

A

may occur with sparing of main median nerve due to compression by nearby muscles or from fractures of the forearm

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65
Q

injury to ulnar nerve

A

fractures to medial epicondyle or compression of the nerve against the bone or with fractures or lacerations to the ventral medial side of the wrist

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66
Q

injury to musculocutaneous nerve

A

not common, but can occur

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67
Q

lesions of the brachial plexus

A

2 most common: upper brachial plexus injury and lower brachial plexus injury that occur at the roots of the plexus

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68
Q

upper brachial plexus injury

A

ie Erb’s palsy. most often occurs as a birth injury or fall on the shoulder. involves musculocutaneous, axillary, and suprascapular nerves

69
Q

lower brachial plexus injury

A

ie Kumpke’s palsy. can occur as a birth injury or sever abduction of the arm. primarily involves the ulnar nerve

70
Q

5 branches of the axillary artery in the axilla

A

superior thoracic, thoracoacromial, lateral thoracic, subscapular, anterior humeral circumflex and posterior humeral circumflex

71
Q

brachial artery

A

arises in the arm from the axillary artery. has one major branch, the deep brachial, which supplies the posterior compartment

72
Q

collateral branching of arteries in the upper limb

A

present around the shoulder, elbow and wrist joints to bypass any blockages of the main artery

73
Q

most common causes of shoulder pain in adults

A

subacromial impingement syndrome and rotator cuff problems

74
Q

steps to physical exam of shoulder

A

inspection, palpation, ROM, strength testing, special tests

75
Q

Embryonic genes with roles of body patterning

A

FGF, Wnt-7a, Shh, and Homeobox (Hox) genes

76
Q

Proximal to distal formation

A

ie humerus develops then radius then wrist

77
Q

Proximal to distal limb development

A

dependent on FGF (fibroblast growth factor) gene. FGF produced by mesoderm, causing proliferation of ectoderm at the site where the limbs form

78
Q

AER (apical ectodermal ridge)

A

ridge formed by the proliferating ectoderm in limb development. AER begins to produce FGF, causing proliferation of the mesoderm

79
Q

Progress zone

A

the proliferating mesoderm caused by the FGF produced by the AER

80
Q

digit formation

A

apoptosis occurs in the AER to separate it into 5 separate ridges.

81
Q

Dorsal to ventral limb development

A

Wnt-7a is the most important gene. It’s a signaling protein expressed by the AER. It activates a gene called LMX-1 in the mesoderm, causing it to form dorsal structures. Without LMX-1, 2 ventral sided would form

82
Q

Engrailed1

A

a transcription factor expressed on the ventral side of the limb bud. This represses Wnt-7a

83
Q

Anterior to posterior limb development

A

depends on Shh (sonic hedgehog) gene. Shh is signaling protein produced at posterior base of limb buds. Shh diffuses across the limb bud to activate family of transcription factors called homeobox (hox) genes

84
Q

Zone of polarizing activity (ZPA)

A

these are the cells that produce Shh

85
Q

hox genes

A

define the pattern of differentiation from thumb (anterior or cranial) to little finger (posterior or caudal), as well as segmental organization of entire embryo in a cranial to caudal direction

86
Q

intermembranous (membranous or dermal) ossification

A

forms the flat bones of the skull and bones of the face. Mesenchyme cells differentiate directly into osteoblasts

87
Q

mesenchyme

A

loosely organized, mainly mesodermal tissue that develops into connective and skeletal tissues, including blood and lymph

88
Q

osteoblasts

A

lay down primary or woven bone (irregularly arranged collagen fibers) that is remodeled into lamellar bone (parallel alignment of collagen into sheets)

89
Q

endochondral ossification

A

forms the long bones, vertebral column, pelvis, sternum, and skull base. Mesenchyme differentiates into chonroblasts, which produce a cartilage model. Cartilage becomes vascularized, bringing in osteoblasts and restricting chondrocytes to the ends (epiphyses) of the bone

90
Q

zone of proliferating cartilage

A

where proliferation occurs at the epiphyseal side of the growth plate in long bones

91
Q

diaphysis

A

shaft of long bone

92
Q

zone of hypertrophic cartilage

A

chondrocytes toward the diaphysis undergo hypertrophy and apoptosis

93
Q

zone of ossification

A

where the chondrocytes mineralize the matrix surrounding the zone of hypertrophic cartilage

94
Q

bone growth occurs

A

as long as rate of proliferation=rate of cell death and ossification

95
Q

dermatome

A

an area of skin innervated by a single spinal nerve and its dorsal root ganglion

96
Q

limb defects

A

rare and mainly hereditary. weeks 4-5 are most susceptible to teratogen induced malformations

97
Q

meromelia

A

a reduction defect of the limb resulting in part of the limb being absent

98
Q

amelia

A

reduction defect of limb resulting in entire limb being absent

99
Q

phocomelia

A

type of meromelia when hands or feet project directly from the shoulder or hip

100
Q

thalidomide

A

given to women for nausea in between 1957-62 and caused meromelia when taken during week 5 and amelia when taken during week 4. defined critical period for limb development between 24-36 days

101
Q

mechanism of thalidomide as teratogen

A

disruption of the AER and its production of FGF affecting proximal and distal limb development

102
Q

Polydactyly

A

formation of extra digits, a duplication defect. Shh is expressed in the anterior limb bud in addition to its usual posterior expression causing mirror duplication of digits . Caused by ZPA duplication and can be inherited or teratogen induced

103
Q

syndactyly

A

a dysplasia, or malformation of part of the limb. abnormal fusion of the digits resulting from reduced apoptosis

104
Q

Spinal cord segments contributing to musculocutaneous nerve

A

C5, C6, C7

105
Q

Spinal cord segments contributing to axillary nerve

A

C5, C6, C7, C8, T1

106
Q

Spinal cord segments contributing to ulnar nerve

A

C8, T1

107
Q

Spinal cord segments contributing to Median nerve

A

C5, C6, C7, C8, T1

108
Q

Spinal cord segments contributing to Radial nerve

A

C5, C6, C7, C8, T1

109
Q

lateral cord of brachial plexus

A

gives off musculocutaneous nerve and contributes to median nerve

110
Q

posterior cord of brachial plexus

A

gives off axillary nerve and radial nerve

111
Q

medial cord of brachial plexus

A

gives off ulnar nerve and contributes to median nerve

112
Q

Drop arm test

A

rotator cuff, primarily supraspinatus muscle. Pt abducts arm and slowly lowers it to 90 degrees. Arm will then drop to side if rotator cuff is injured

113
Q

Impingement tests

A

Neer’s sign and Hawkin’s test

114
Q

Speed’s test

A

Biceps tendon. Forward flex shoulder against resistance while maintaining elbow in extension and forearm in supination. Positive test=tender in bicipital groove

115
Q

O’brien’s test and Crank test

A

Labral tear

116
Q

Instability tests

A

anterior release and relocation test

117
Q

Neer’s sign

A

an impingement test. Patient seated with arm at side and palm down. Examiner stabilizes scapula and raises arm. Positive test=pain. Means rotator cuff tendons are pinched under coracoacromial arch

118
Q

Hawkin’s test

A

an impingement test. Patient standing, examiner forward flexes shoulder to 90 degrees and forcible internally rotates arm. Positive test=pain in area of superior glenohumeral joint or AC joint. Suggests subacromial impingement or rotator cuff tendonitis

119
Q

Obrien’s active compression test

A

Tests for labral tear (SLAP lesion) patient standing, arm forward flexed 90, adducted 15 to 20 with elbow straight. Full internal rotation so thumb pointing down. Examiner applies downward force. Patient externally rotates arm so thumb pointing up, examiner applies downward force again. Positive test=pain or painful clicking elicited with thumb down and decreased or eliminated with thumb up

120
Q

Crank test

A

Tests for labral tear (SLAP lesion). Shoulder elevated to 160 in scapular plane. Gentle axial load is applies through glenohumeral joint with one hand while other does IR and ER. Positive test = pain, catching or clicking in shoulder.

121
Q

apprehension test - sitting

A

90 abduction, examiner applies slight anterior pressure to humerus and externally rotates arm. Positive test=patient expresses apprehension that arm will dislocate. May indicate loose capsule and/or ligaments

122
Q

apprehension test - supine

A

patient supine with affected shoulder at edge of table and arm abducted 90. Examiner externally rotates by pushing forearm posteriorly. Positive=patient apprehensive

123
Q

relocation test

A

performed after positive anterior apprehension test. Patient supine, examiner applies posterior force on proximal humerus while externally rotating arm. Positive=patient expresses relief

124
Q

Apley scratch test

A

Reach for upper scapula, compare bilaterally - tests ER and abduction. Reach for lower scapula, compare bilaterally. Tests IR and adduction

125
Q

Strength of ER

A

tests infraspinatus and teres minor

126
Q

Strength of IR

A

tests subscapularis

127
Q

Empty can test

A

arms straight out, elbows locked, thumbs down, arms 30 degrees in scapular plane. Attempt to abduct arms against resistance. Tests supraspinatus

128
Q

Lift off test

A

Rest dorsum of hand in lumbar area and try to push examiners hand away. Tests subscapularis

129
Q

Purpose of connective tissue

A

provide structural support and connecting framework (or stroma) for all other tissues of body. Main constituent is fibers and ECM

130
Q

Fibroblast

A

“resident cell of connective tissue.” produces and maintains ECM

131
Q

Types of Connective tissue

A

Loose, Dense regular, and dense irrecular

132
Q

Loose connective tissue

A

has more cells than collagen fibers and is generally found surrounding blood vessels, nerves, and muscles

133
Q

Dense regular connective tissue

A

more collagen fibers than cells. fibers are preferentially oriented, as in tendons, ligaments, and cornea. Generally poorly vascularized, which impacts healing time

134
Q

dense irregular connective tissue

A

more collagen fibers than cells. Fibers are randomly oriented, as in dermis of skin and wall of intestine

135
Q

main components of ECM

A

glycosaminoglycans, proteoglycans, adhesive glycoproteins, and collagen

136
Q

Glycosaminoglycans (GAGs)

A

long, unbranched polysaccharides consisting of repeating disaccharide units. Highly negatively charged and associate with large amounts of water to create hydrated gels with high viscosity and low compressibility.

137
Q

Important GAGs in physiology

A

hyaluronic acid, dermatan sulfate, chondroitin sulfate, heparin, heparan sulfate, and keratan sufate

138
Q

Proteoglycans

A

family of macromolecules composed of protein core with at least 1 glycosaminoglycan covalently bonded. Simplest is decorin. Aggrecan is a more complex one, and is found in articular cartilage. Highly negatively charged. Help to organized matrix by interaction with other molecules. Component of basal lamina of epithelial cells

139
Q

Adhesive glycoproteins

A

Help facilitate attachment of cells to ECM. Important once are laminin and fibronectin.

140
Q

Collagen

A

most abundant proteins in the animal kingdom. The major protein of ECM. At least 28 types. Types I, II, and III are most abundant.

141
Q

Cartilage

A

specialized type of connective tissue that consists of chondrocytes embedded in ECM. Usually surrounded by a fibrous connective tissue layer called perichondrium. its avascular; receives nutrition by diffusion through ECM

142
Q

Interstitial growth of cartilage

A

division of existing chondrocytes within cartilage

143
Q

Appositional growth of cartilage

A

production of new chondroblasts and chondrocytes at at the surface of cartilage from stem cells in perichondrium

144
Q

Hyaline cartilage

A

surrounded by perichondrium, chondrocytes surrounded by matrix of type II collagen proteoglycans and water. Found in skeleton of embryo, articular cartilage in joints, and cartilage of respiratory tract

145
Q

Elastic cartilage

A

surrounded by perichondrium, chondrocytes surrounded by matrix of type II collagen, proteoglycans, and elastic fibers. Found in external ear and epiglottis

146
Q

fibrous cartilage

A

NO perichondrium, chondrocytes surrounded by matrix of type I collage. Resembles dense fibrous CT. Found in intervertebral discs, menisci of knee, and pubic symphysis.

147
Q

Bone

A

rigid, inflexible connective tissue in which ECM has been mineralized with calcium and phosphate. It is highly vascularized and metabolically very active. constantly remodeled and reshaped

148
Q

Organic component of bone ECM

A

called osteoid; composed of type I collagen and proteoglycans. 3 main noncollagenous glycoproteins are osteocalcin, osteopontin, and osteonectin.

149
Q

Inorganic component of bone ECM

A

called bone mineral. consists of calcium and phosphate salt called hydroxyapatite. contributes to strength and rigidity of bone

150
Q

4 major cell types in bone

A

osteoblasts, osteocytes, osteoclasts, and osteoprogenitor cells

151
Q

osteoblast

A

derived from osteoprogenitor cells. main bone forming cells. generally cuboidal shaped and found on surface of bone. Actively deposit osteoid along the osteoblast-bone interface3. initiate and control the mineralization of the osteoid

152
Q

primary or woven bone

A

initially ECM produced by osteoblast. Matrix with loose randomly oriented collagen fibers and low hydroxyapatite

153
Q

secondary or lamellar bone

A

remodeled from primary bone. organized sheets of collagen fibers (lamellae) and high hydroxyapatite

154
Q

osteocyte

A

osteoblasts that become surrounded in bone matrix stop producing osteoid, flatten out and transform into osteocytes. found in lacunae.

155
Q

osteoclast

A

large multinucleated cells found on surfaces of bone whose primary function is to degrade bone matrix

156
Q

cortical/compact bone

A

bone matrix arranged into cylindrical structures called osteons. Osteon has central canal called Haversian canal surrounded by 4-10 concentric lamellae of bone cells and matrix.

157
Q

trabecular/cancellous bone

A

contains layers of lamellae that form bony trabeculae that project into the marrow cavity. NO osteons. Osteocytes interspersed randomly. surface often covered with osteoblasts and osteoclasts

158
Q

calcium homeostatsis

A

done by activity of osteoblasts and osteoclasts. Prevents hypocalcemia and hypercalcemia. Calcium needed for glandular secretion, muscle contraction, and neuronal function.

159
Q

PTH secretion

A

activates osteoblast receptors in response to low plasma calcium to secrete osteoclasts

160
Q

Calcitonin secretion

A

activates osteoclast calcitonin receptors in response to high plasma calcium to immobilize osteoclasts and retract them from bone surface.

161
Q

osteoblast

A

synthesize bone matrix

162
Q

osteoclast

A

specialized macrophages derived from monocytes. Secrete acid (H+) and proteases to dissolve bone matrix as osteoid first that later becomes minealized

163
Q

osteocyte

A

control local calcium and phosphate levels

164
Q

bone matrix

A

consists of type I collagen and hydroxyapatite, which contains 99% of body’s calcium and 85% of its phosphorus

165
Q

bone turnover

A

modulated by osteoblasts! osteoclasts are “slaves” to osteoblasts.
RANK/RANK-L, osteoprotegerin (OPG) and M-CSF

166
Q

RANK

A

receptor on surface of osteoclasts that, when bound to ligand, stimulates the osteoclast

167
Q

RANK-L

A

found on the osteoblasts. it’s the ligand that binds to RANK on the osteoclast to stimulate them

168
Q

Osteoprotegerin (OPG)

A

decoy receptor for RANK-L. Made by osteoblasts and prevents RANK-L from binding RANK. Decrease osteoclast activity

169
Q

M-CSF

A

secreted by osteoblasts to stimulate osteoclasts

Clinical Morphology (25 decks)

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