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Flashcards in 40.tissues of MS Deck (41)
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1
Q

fmost abundant protein in the body

A

collagen

2
Q

T/Fproteoglycans are one class of glycoproteins

A

TRUEGlycoprotein = polypeptides covalently linked by carbohydratesProteoglycan = one class of glycoproteins, they are a polypeptide that is covalently linked to amino sugars (GAGs)

3
Q

define stress vs strain

A

stress= force per unit areastrain= deformation produced in a given direction

4
Q

what is adaptation of a tissue

A

ability of the tissue to actively maintain specific properties (such as strength and stiffness) that are required for their function and integrity

5
Q

properties of all musculoskeletal tissue

A

contain a small amount of progenitor cellsmechanosensitivitymechanotransductioncellular interconnectedness (except NOT in cartilage)

6
Q

components of ECM

A

–collagen–proteoglycans (aggrecan)–elastin/elastic fibers–Misc proteins, proteolipids, glycoproteins (fibronectin)

7
Q

tensile properties of collagen rich connective tissues are determined by what factors

A

–intrinsic mechanical properties of collagen type–orientation–packing–diameter of collagen fibrilsex. tendon–parallel and dense collagen, therefore withstand unidirectional tensile loads and high stiffness in that directionarticular cartilage–smaller, sparse, weblike collagen, therefore withstands multidirectional tension and resistance to deformation in several directions

8
Q

major proteoglycan in the body

A

glycoprotein–>proteoglycan = AGGRECAN (made up on GAGS–keratin and chondroitin sulfate)massive 100 aggrecan per hyaluronic acid backbone, linked to hyaluronic acid via link protein, high level of hydration and turgidity (critical for compressive properties—ex. articular cartilage)

9
Q

types of classes of glycosaminoglycans

A
  1. glycosaminoglycans–keratan sulfate, heparan sulfate2. galactosaminoglycans–chondroitin sulfate
10
Q

what is hyaluronic acid

A

nonpeptideconjugated, nonsulfated glycosaminoglycan

11
Q

what is the most abundant GAG in the body

A

chondroitin sulfate

12
Q

name the non sulfated GAG

A

hyaluronic acid

13
Q

where is keratin sulfate most prevalent in

A

bone and cartilage

14
Q

most negatively charged GAG

A

heparan sulfate

15
Q

characteristics of elastin/elastic fibers in connective tissue

A

flexibleextensibleresilientinsolublerecoilundergo elastogenesis during reparative phase fun fact: make up majority of Nuchal Ligament

16
Q

deformation or strain of elastic fibers

A

70% of their resting lengthmax extension: 220% before losing strength

17
Q

two forms of bone in the adult:

A
  1. cortical—compact, osteonal bone 2. cancellous—spongy, trabecular bone
18
Q

what type of collagen is the periosteal ECM and bone primarily made up of

A

type I(articular cartilage is type II)

19
Q

difference btwn woven and lamellar bone

A

lamellar bone–highly organized, layered bone, alternating orientationwoven bone–loose, disorganized (seen in initial phases of endochondral ossification either during growth or indirect fracture healing)

20
Q

mineral content of bone

A

calcium hydroxy apatite

21
Q

T/Fbone is least strong under tension

A

TRUEstrongest under compressionweakest under tension

22
Q

what is wolff’s law

A

ability of bone to remodel adaptively in response to a mechanical load

23
Q

which cell is the primary mechanotransducer in bone

A

osteocyte

24
Q

most bone remodeling occurs on what surface

A

trabecular or cortical surfacesHOWEVER, can still occur WITHIN Haversian system of cortical bone (osteoclasts cutting cones, followed by osteoblasts–direct or primary cortical remodeling)

25
Q

how fast do osteoclastic cutting cones travel per day

A

cutting cones progress by 50-100 microns per daydirect bone healing WITHIN Haversian system

26
Q

what makes up cartilage

A
  1. water2. collagen (type II for articular cartilage, type I for fibrocartilage)3. proteoglycan (aggrecan)4. glycoproteins
27
Q

zones of articular cartilage

A

3 unmineralized zones—TIDEMARK—1 mineralized zoneI superficial or tangential zone—highest cell density, small flat chondrocytes, orientated with long axis parallel w surfaceII transitional zone; larger rounder chondrocytesIII radiate zone; larger cells arranged perpendicular to surfaceIV calcified zone

28
Q

collagen and proteoglycan turnover in the adult dog

A

VERY SLOWcollagen turnover 120 YEARSproteoglycan turnover 300 DAYS

29
Q

T/FThe low modulus of elasticity of articular cartilage allows it to deform and increase the congruity of opposing articular surfaces

A

TRUE

30
Q

fx of tendons

A

attach muscle to bonetransfer force of muscle to skeleton

31
Q

fx of ligaments

A

originate and insert onto bonesjoint stability and constrain joint motion

32
Q

type of collagen in tendons and ligaments

A

type I collagen

33
Q

what does it mean that tendons and ligaments are highly anisotropic

A

directionally dependenthigh stiffness/strength during TENSIONnegligible stiffness/strength during COMPRESSION

34
Q

viscoelastic property of tendons and ligaments

A

rate of loading effects their responsestress relaxation and creep occur during low loading over a long time

35
Q

what is an entheses

A

specialized region of tendon or ligament at sites of insertion upon a bonefibrous or fibrocartilaginous (ligaments)ex. Sharpey’s fibers

36
Q

largest organ in the body

A

skeletal muscle

37
Q

contractile unit of a myofibril

A

sarcomere (overlapping Actin and Myosin)repeating sarcomere–>myofibril–>myofibers–>muscle fibers (endomysium)–>fascicles (perimysium)–>muscle bellies (epimysium)

38
Q

describe a sarcomere unit

A

heavy central chain of myosinoverlapping light chains of actinA band = central where actin and myosin overlapZ disc = each side of the sarcomereI band = centered around Z disc , contain only actin

39
Q

describe muscle contraction physiology

A

nerve signal–Ach and release of calciumCa bind troponin–>structural change to move tropomyosin away from binding site for myosin on actinglobular head of myosin attaches to actinuses free ATP to drive ratchet life change and sliding of actin along myosin–>shortening of sarcomere, contraction of muscle

40
Q

two basic types of muscle fibers in skeletal muscle

A

type 1: slow twitch, rich in mitochondria for sustained contraction of low velocity, low force (oxidative mx)type II: fast twitch, fewer mitochondria, rich in myofibrils; work in transient high force high velocity contractions

41
Q

T/Ftransfer of force to muscle occurs primarily at the level of the perimysium

A

TRUEforce transfer occurs primarily at the level of the perimysium which has more densely organized and multilayered collagenous structure compared to the endomysium.

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