EXAM 1 Flashcards

Question

Torque:

Answer 1

a rotational/turning force or the turning effect produced by a force that is not applied through the object’s center of mass. Force (F) and moment arm (r) are directly proportional to torque → the more force, the greater the torque & the longer the moment arm, the greater the torque Formula: T = Fr Our muscles attach to our bones on the other side of the joint - so when the muscles contract, they apply the pulling force on the bones and not through the axis of rotation in the joint, generating a torque.

Answer 2

rigid segment that rotates about the fixed axis (fulcrum) and a force is applied to this segment at some distance away from the axis of rotation, so that it generates a turning effect (a torque). Our muscles contract to generate the turning force (effort) of the bony segment (rigid bar) about the joint’s axis or rotation (fulcrum) to overcome some resistance Classes of Levers

Answer 3

axis of rotation is between the force and resistance Good for balancing opposing forces to make steady movements

Answer 4

the resistance is between the force and axis of rotation. Good for magnifying the force movement so a larger resistance can be moved by a smaller force (less force exertion)

Answer 5

the force is between the axis and the resistance Good for amplifying speed of range of motion Most levers in the human body are 3rd class

Answer 6

when the loads that are applied in one direction - Tension, compression, and shear loads

Answer 7

when the direction of the forces is different to each other - Bending, torsion, some other combination loads

Answer 8

a squeezing force where the ends/sides are pressed together Produced by the pull of contracting muscles Collinear → the forces are aligned with each other

Answer 9

a pulling or stretching force where the ends/sides are being pulled in opposite directions Produced by muscles, gravity, external forces on bone Collinear → the forces are aligned with each other

Answer 10

sliding or slipping force Two noncollinear forces pointing in opposite directions from each other

Answer 11

twisting force creating by opposing forces The ends of the structure is twisted in opposite directions → create shear forces within the structure

Answer 12

combination of compression and tension loads occurs when the ends of the structure are forced in the same direction that is opposite to the unsupported center of the structure Inner, center portion in compressed and outer, center portion is tensed

Answer 13

hard, dense tissue that is not completely rigid and made up of three types of bone cells: proteins (collagen, non-collagenous), minerals (calcium carbonate & calcium phosphate), and water

Answer 14

provide compressive strength/stiffness; gives bones dense/hard nature (make up 60%-70%)

Answer 15

provide the bones flexibility and stretchiness; keeps it from breaking under heavy loads

Answer 16

aids nutrient transport and allows waste to leave the bone

Answer 17

Simple machines → magnify force, speed, and range of motion Bones at as a “rigid” segment lever; maybe also the resistance force In joints, muscles can cause the bony segment to rotate about the joint, acting as the axis (fulcrum) Muscles attach to bones & pull on attachment site when contracting, causing tensile force on the bones at attachment sites

Answer 18

Bones provide framework to maintain posture and withstand forces Bones transfer forces to allow for movement Long bones (provide structure and support) → humerus, radius, ulna, femur, tibia, fibula Vertebrae (irregular bone) → stacked on top of each other to help body stay upright and move around

Answer 19

Bones - the densest tissue in the body that protect tissues and structures Skull - protects brain Vertebrae - protects the spinal cord Ribs - protects heart, lungs, liver, etc Bones classified as flat or irregular often serve a protective function

Answer 20

Bones act as a storehouse for essential minerals for the body like calcium, magnesium, potassium, phosphorus, sodium, and zinc 99% of body’s calcium is stored in the bones & teeth Body withdrawn minerals (calcium) from the bones when needed (for muscle and nerve function) Proper nutrition (high) calcium intake is important for healthy bones

Answer 21

Bones are responsible for the formation of blood cells, aka hematopoiesis Occurs in red bone marrow in cancellous (trabecular) bone Example of trabecular bones - vertebrae, femur, and ilium Blood cells mature → stem cells → differentiate into erythrocytes (red blood cells), leukocytes (white blood cells), or thrombocytes (platelets)

Answer 22

long, rounded ended; slender middles Provide support and structure to the body and give extremities their shape Acts as rigid bar in a lever system and provide sites to muscle attachment Ex - humerus, radius, ulna, fumer, tibia, fibula Ex - hand (metacarpals), fingers, forefoot (metatarsals), and toes are all small but still considered long bones.

Answer 23

small(ish), rounded/cube-like shapes Transmit forces across joints; absorb shock Ex - carpals (wrist); tarsals (foot)

Answer 24

flat curved shape Protect underlying organs/soft tissue and provide areas for attachment sites of tendons and muscle attachments Ex - ribs, ilium, sternum, clavicle, scapula, skull Some flat bones fuse together → irregular bones

Answer 25

contain a unique shape and size Specialized functions Ex - vertebrae, ischium, pelvis (as a whole), skull (as a whole)

Answer 26

usually small and rounded Increase the lever arm (muscle movement) of a muscle and the mechanical efficiency of the muscle Ex - patella (increases the amount of torque that is generated by the quadriceps muscle group - it increases the distance b/w the muscles’ line of action & the joint’s axis of rotation) Ex - bones in the thumb (metacarpophalangeal joint) Ex - bones in the great toe (metatarsophalangeal joint)

Answer 27

act to connect the anatomical segments of the body; allow us to have complexity when performing tasks

Answer 28

least mobile, most stable (“immovable”) Primary function is protection and stability Ex - tooth sockets, suture joints of skull (become immovable when on reaches adolescence)

Answer 29

medium mobility; medium stability (“slightly moveable”) Primary function is stability and transmitting forces/absorbing shock Three subclasses:

Answer 30

Syndesmosis → fibrous in nature with little motion; provides stability & transmits forces (ex - distal tibiofibular joint in lower leg) Symphysis → cartilaginous joint where the articulating surfaces are joined by fibrocartilage, like a disc (ex - pubic symphysis of pelvis) Synchondrosis → cartilaginous joint where articulating surfaces are joined by hyaline cartilage (ex - costochondral joints b/w ribs and sternum)

Answer 31

most mobile, least stable (“freely moveable”) Commonly found in extremities Aka ~ synovial joints (due to the joint being surrounded by synovial fluid → lubricates joint & provides nutrients/removes waste) Contains 5 components hyaline cartilage on the articulating surfaces synovial membrane (thin layer on deep surface of the joint capsule) ligaments that provide support & guide the joint through its motion blood vessels other sensory nerves

Answer 32

3 DoF, but least mobile; small range of motion Can move in any direction, but not very far Flat shape and the articulated surfaces glide/slide past each other in small amounts Ex - acromioclavicular joint of shoulder girdle complex (allows forces to be transferred b/w scapula & clavicle; permits small motions to enhance joint range of motion) Ex - joints b/w carpal bones of the wrist

Answer 33

1 DoF, uniaxial; stable > mobile; medium range of motion Articulating surface has a round convex shape that fits into a deeper concave surface Only permits flexion and extension; no abduction/adduction Ex - humeroulnar joint (elbow)

Answer 34

1 DoF; uniaxial; stable & mobile, medium range of motion Permits rotation about the bony segment’s long axis Ex - proximal radioulnar joint (near elbow) - only permits supination and pronation motions → transverse plane

Answer 35

2 DoF, biaxial; stable < mobile; MED-large range of motion Articulating surfaces are concave and convex (nest together) Prohibits axial rotation, but can produce circumduction Less mobile than condyloid joints due to more bony contact Ex - carpometacarpal joint of the thumb; subtalar joint in foot

Answer 36

2 DoF, biaxial; more mobile, med-LARGE range of motion Permits flexion, extension, abduction, adduction Allows circumduction and diagonal plane motion Articulating surfaces are concave and convex (nest together) Prohibits axial rotation Ex - radiocarpal joint (wrist) & metacarpophalangeal joint (knuckle) → can both flex, entend, abduct, and adduct

Answer 37

3 DoF, multiaxial; very mobile, not very stable; large ROM Rely on other joints, ligaments, and muscles for support One end of the joint has a round projection (the “ball” or convex) that articulates with a depression on the adjoining bone (the “socket” or concave) Can flex, extend, abduct, adduct, rotate internally/externally Allows circumduction and diagonal plane motion Ex - glenohumeral joint (shoulder) & femoroacetabular joint (hip) → both produce circumduction or other combinations of external rotation while in abduction.

Answer 38

incorporates that when a load or stress is applied to our bones, they are capable of remodeling to adapt to the stress

Answer 39

process of osteoclasts removing old bone cells in order to repair microcracks while osteoblasts create new bone cells (3-6 month cycle) the mass and shape of bone can change based on the load

Answer 40

builds new bone cells

Answer 41

detects changes in load; important for communication signals osteoclasts and osteoblasts

Answer 42

absorb old bone (minerals go back into bloodstream)

Answer 43

Increase in bone mass due to more osteoblasts produce bone cells than osteoclasts removing them Strength training

Answer 44

Bones weakens over time due to more osteoclasts breaking down more bone than osteoblasts replacing it Ex - bed rest or disuse

Answer 45

cartilage, ligaments, and tendons → connective tissue that help joining two or more structures together

Answer 46

dense type of connective tissue; less dense than bone

Answer 47

reduce friction among articulating surfaces so they may move smoothly; also absorb shock from compressive and shear (sliding) forces. Form of hyaline cartilage Found on articulating surfaces, like the epiphyses of long bone Doesn’t have direct blood supply/sensory nerves → damage to articular cartilage of a joint can have debilitating effects as it does not heal easily.

Answer 48

provides structural support to a joint; increases surface area of the bones in contact with each other which enhances the joint’s stability; very dense Only provides static stability Has little to no blood supply and sensory nerves Ex - glenoid labrum (shoulder joint), the acetabular labrum (hip joint), and the menisci (knee joint)

Answer 49

dense, connective tissues that attaches to the bone to form a joint and function to stabilize the joint and guide it through the appropriate ranges of motion Composed mostly of collagen proteins, elastin, and water Not a contractile tissue → only provides static support Little blood supply → makes it hard for them to heal Provide important sensory information about a joint’s position in space and its changes in motion Ex - medial collateral ligament of the knee joint (runs vertically with the bone) resists further stretching in that direction which would occur with a motion like valgus (knock knee; knees come together)

Answer 50

connects muscle to bone and can stretch more than ligaments; composed of dense bundles of collagen, elastin, and water Provides dynamic support to a joint when the muscle is contracted Provides static support to a joint when a muscle is relaxed Minimal blood supply; rich in sensory nervous (ex - golgi tendon organ) They can be long and narrow or broad and flat Aponeurosis -

Answer 51

fibrous connective tissue that holds other soft tissues like muscles and tendons together (tough; has little stretch)

Answer 52

type of fascia that runs perpendicular to tendons (acts similar to a seat belt restraint) Ex - extensor retinaculum of the dorsal wrist → holds the extensor tendons of the fingers in place to prevent them from bowing out away from the joint (decreasing muscle efficiency and torque production)

Answer 53

fibrous, connective tissue that surrounds a joint to enclose the synovial fluid that is produced by the synovial membrane provide static stability to a joint → not a contractile tissue only found in synovial (diarthrodial) joint stability depends on the percentage of collagen and elastin People who are more “bendy” have higher elastin Laxity → excess joint motion (hypermobile people)

Answer 54

serve as the attachment site for tendons, muscles, and ligaments They stick out from the bone; may be round with a sharper edge Ex - tibial tuberosity → the bony process on the anterior surface of the proximal tibia and serves as the attachment site for the patellar tendon

Answer 55

act to contain other structures like a muscle, tendon, nerve, or blood vessel; and can also act as the articulating surface of a joint or protect a structure They are concave surfaces or depressions within the bone Depth (concavity) ranges from shallow to deep Shallow → glenoid fossa of the shoulder joint Deep → acetabulum of the hip joint Size ranges from small to large depressions Small → coronoid fossa of the humerus Large → infraspinous fossa of the scapula

Answer 56

connective tissue that connects to bones via tendons or aponeuroses A contractile soft tissue comprised of two contractile proteins → actin & myosin Types → skeletal, cardiac, smooth Sarcomere - smallest unit of the muscle; contains actin (connected to Z-LINE) and myofilaments (connected to M-LINE) Myofibrils are bundled together to form a muscle fiber which is surrounded by a connective tissue called the endomysium. Several muscle fibers are bundled together to form a muscle fascicle which is wrapped in a connective tissue called the perimysium

Answer 57

High speed movements Relatively long and run the whole length of the muscle; this allows them to shorten quite a bit. Muscle is aligned in the same direction as the tendon, length of the muscle-tendon-unit, and the other fibers in the muscle Disadvantage - lower force production. Subtypes: Fusiform, Radiate, Sphincter, Flat, Strap

Answer 58

Run at an angle to the tendons and muscle-tendon-unit which gives them a feather-like appearance Diagonal orientation of the fibers → much shorter and less shortening capacity than parallel muscle. More force production capacity Arrangements: Unipennate - only 1 direction of fibers all in the same angle Bipennate - 2 directions of fibers that run diagonally from the tendon that runs the whole length of muscle. Multipennate - fibers that run in more than two different directions

Answer 59

any muscle that performs joint motion when performing a shortening/concentric contraction (they are agonist of that joint motion) Agonist motion → Joint motion that occurs during a shortening or concentric contraction Prime movers → help the most (others just assist) Ex: muscles of the hamstring are agonists of knee flexion; when these muscles contract concentrically, they produce knee flexion.

Answer 60

a muscles that cause a joint motion that is the opposite of the agonist action Located on the contralateral side of the joint from the agonist Important for controlling/decelerating quick movements Ex: quadriceps causes knee extension when they contract concentrically → agonists for knee extension; so the hamstrings (agonist for knee flexion) are the antagonist of knee extension

Answer 61

What does the grouping matter How does it work with respect to the antagonist muscle group

Answer 62

occurs when the MTU shortens (example: lifting phase of bicep curl - elbow flexor muscles shorten/produce greater force than gravity) Attachment sites of muscles are pulled towards muscle’s center Used to start motion or speed it up Torque generated my muscles > torque generated by external forces

Answer 63

occurs when the MTU lengths (example: lowering phase of a bicep curl - elbow flexors produce less torque than force of gravity) Actin & myosin still binding; slide past each other as muscle lengthens Joint motion is present Torque generated by muscles < torque from external forces

Answer 64

static contractions (example: holding the elbow flexed at 90 deg. - elbow flexor match external torque from gravity) Actin and myosin bind together Joint motion does not change Used to prevent undesired motion and stabilize Muscle torque generated = external torque generated

Answer 65

tension force generated when the muscle contracts; depends on # and size of motor units recruited

Answer 66

shows muscle’s ability to produce force is related to the length of the muscle-tendon unit

Answer 67

length of muscle-tendon unit where there is a mex crossbridge formation between actin and myosin Muscle can produce the highest amount of active force in the state

EXAM 1 Flashcards

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