Anatomy and Physiology 1 Exam 3 UWEC

Synovial Joint/Diarthrosis

joint in which two bones are separated by a joint cavity

Most are freely mobile,Most structurally complex type of joint, Most likely to develop painful dysfunction

Articular Cartilage

layer of hyaline cartilage that covers the facing surfaces of two bones Usually 2 or 3 mm thick

Joint (articular) cavity

separates articular surfaces

Synovial Fluid

slippery lubricant in joint cavity, Gives it a viscous, slippery texture, nourishes articular cartilage and removes waste, makes movement of synovial joints almost friction free, has albumins to have osmotic balance

Joint (articular) capsule

connective tissue that encloses the cavity and retains the fluid Outer fibrous capsule: **(very tough)** continuous with periosteum of adjoining bones. Inner, cellular, synovial membrane: composed mainly of fibroblast-like cells that secrete synovial fluid and macrophages that remove debris from the cavity

Meniscus

moon-shaped cartilage in knee; in each knee, extend inward from the left and right, absorb shock and pressure, guide bones across each other and improve their fit together

Bursa

fibrous sac filled with synovial fluid, located between muscles, where tendons pass over bone, or between bone and skin Cushions muscles, helps tendons slide more easily over joints, modifies direction of tendon pull

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Tendon Sheath

Elongated cylindrical bursa wrapped around a tendon In hand and foot

Tendon

strip of collagenous tissue attaching muscle to bone

Ligament

strip of collagenous tissue attaching one bone to another

warms

Exercise _____ synovial fluid, Becomes less viscous, more easily absorbed by cartilage

Lever

any elongated, rigid object that rotates around a fixed point called a fulcrum.

Resistance arm and effort arm are described relative to fulcrum

Rotation

Rotation occurs when an effort applied overcomes resistance (load) at some other point

Range of motion (ROM)

the degrees through which a joint can move, determined by: Structure of the articular surfaces, Strength and tautness of ligaments and joint capsules, Action of the muscles and tendons

Multiaxial Joint

shoulder joint has three degrees of freedom or axes of rotation

Classes of Synovial Joints

ball-and-socket, condylar, saddle, plane, hinge, pivot

Ball and socket joints

Smooth, hemispherical head fits within cup-like socket Only multiaxial joints in body Examples: shoulder, hip

Condylar (ellipsoid) joints

Oval convex surface of one bone fits into a complementary-shaped depression on the other. **Biaxial joints**—movement in two planes Examples: radiocarpal joint, metacarpophalangeal joints

Plane (gliding) joints

Flat articular surfaces, bones slide over each other Usually biaxial joints Examples: between carpal bones of wrist; between tarsal bones of ankle; also between articular processes of vertebrae

Saddle Joints

Both bones have an articular surface that is shaped like a saddle, one concave, the other convex Biaxial joints Examples: trapeziometacarpal (opposable thumb), sternoclavicular joint

Hinge joints

One bone with convex surface fits into a concave depression of another bone Monoaxial joints—move freely in one plane Examples: elbow, knee, joints within fingers, toes

Pivot Joints

A bone spins on its longitudinal axis Monoaxial joints Examples: atlantoaxial joint (C1 and C2), radioulnar joint at the elbow

Zero Position

the position of a joint when a person is in the standard anatomical position Joint movements described as deviating from the _____ ______ or returning to it

Flexion

mvement that decreases joint angle Common in hinge joints

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Extension

movement that straightens a joint and returns a body part to the zero position

Hyperextension

extension of a joint beyond the zero position Flexion and extension occur at nearly all diarthroses, hyperextension is limited to a few

Abduction

movement of a body part in the frontal plane away from the midline of the body

Adduction

movement in the frontal plane back toward the midline

Hyperabduction

raise arm over back or front of head

Hyperadduction

movement of crossing fingers, crossing ankles

Elevation

movement that raises a body part vertically in the frontal plane

Depression

movement that lowers a body part in the same plane

Protraction

the anterior movement of a body part in the transverse (horizontal) plane

Retraction

posterior movement in the transverse (horizontal) plane

Circumduction

one end of an appendage remains stationary while other end makes a circular motion Example: an artist circumducts upper limb when painting a circle on a canvas

Rotation

movement in which a bone spins on its longitudinal axis Rotation of trunk, thigh, head, or arm

Pronation

forearm movement that turns palm to face either posteriorly or downward Head of radius spins Radius crosses stationary ulna like an X

Supination

forearm movement that turns palm to face anteriorly or upward Forearm supinated in anatomical position Radius is parallel to the ulna

Lateral flexion

tilting the head or trunk to the right or left at the midline

Medial axcursion

•movement back to the median, zero position

–__**Side-to-side**__ grinding during chewing

Lateral excursion

right or left movement from the zero position

Inversion

movement in which the soles are turned medially

Eversion

movement in which the soles are turned laterally

Supination of Foot

complex combination of plantar flexion, inversion, and adduction​

Pronation of Foot

complex combination of dorsiflexion, eversion, and abduction​

movement, stability, control of openings, heat production, and glycemic control​

Muscle functions include:

Sphincters

internal muscular rings that control the movement of food, blood, and other materials within body​

Glycemic control

Muscles absorb and store glucose which helps regulate blood sugar concentration within normal range​

600

There are about ___ human skeletal muscles

Myology

the study of the muscular system​

Fascia

Sheet of connective tissue that separates neighboring muscles or muscle groups from each other and the subcutaneous tissue​.

Skeletal, cardiac, smooth

Kinds of Muscles Tissue

Epimysium

Fibrous sheath surrounding entire muscle​, Outer surface grades into fascia; inner surface projections form perimysium​. Holds muscle together

Endomysium

Thin sleeve of loose connective tissue around each fiber​ Allows room for capillaries and nerve fibers ​ Provides chemical environment for muscle fiber

Perimysium

Thicker layer of connective tissue that wraps fascicles​ Carries nerves, blood vessels, and stretch receptors​

Fascicles

bundles of muscle fibers wrapped together​

Fusiform Muscles

thick in the middle and tapered at each end

Parallel Muscles

uniform width and parallel fascicles​

Triangular (convergent) muscles

broad at one end and narrow at the other​

Pennate Muscles

Feather shaped muscles

Unipennate

Muscle where fascicles approach tendon from one side

Bipennate

Muscles where fascicles approach tendon from both sides​

Multipennate

Muscles where bunches of feathers converge to single point​

Muscle Compartment

a group of functionally related muscles enclosed by fascia​ Also contains nerves and blood vessels that supply the muscle group​

Intermuscular septa

Very thick fascia that separate one compartment from another

Aponeurosis

tendon is a broad, flat sheet (palmar aponeurosis)

Retinaculum

connective tissue band that tendons from separate muscles pass under

Direct (fleshy) attachment

Little separation between muscle and bone​ Muscle seems to emerge directly from bone​

Tendons

connect muscle to bone.

Origin

attachment point that doesn’t move when contracted

Instertion

attachment point that moves when contracted

Intrinsic Muscle

entirely contained within a region, such as the hand​(Flexor digitorum brevis)

Extrinsic muscle

acts on a designated region, but has one attachement elsewhere​ Fingers: extrinsic muscles in the forearm​

prime mover (agonist)

Muscle that produces most of force during a particular joint action

Synergist

muscle that aids the prime mover​ May contribute additional force, modify the direction of movement, or stabilize a nearby joint​

Action

effect produced by a muscle to produce or prevent movement ​

Antagonist

opposes the prime mover​ Prevents excessive movement​ Sometimes relaxes to give prime mover control over an action​

Fixator

muscle that prevents movement of bone

Antagonistic pairs

muscles that act on opposite sides of a joint​

Innervation of a muscle

refers to the identity of the nerve that stimulates it

1/4, 3/4

Muscles take of blood at rest, and of blood during exercise

Skeletal muscle

voluntary, striated muscle usually attached to bones

Striations

alternating light and dark transverse bands. are alternating A-bands (dark) and I-bands (light). A band: dark; “A” stands for anisotropic (“different way”) Darkest part is where thick filaments overlap a hexagonal array of thin filaments H band: not as dark; middle of A band; thick filaments only

Sarcolemma

plasma membrane of a muscle fiber

Sarcoplasm

cytoplasm of a muscle fiber

Myofibrils

long protein cords occupying most of sarcoplasm

Glycogen

carbohydrate stored to provide energy for exercise

Myoglobin

red pigment; provides some oxygen needed for muscle activity

Myoblast

stem cells that fused to form each muscle fiber early in development

Satellite cells

unspecialized myoblasts remaining between the muscle fiber and endomysium Play a role in regeneration of damaged skeletal muscle tissue

Sarcoplasmic reticulum (ER)

smooth ER that forms a network around each myofibril:

Terminal cisterns—dilated end-sacs of SR which cross the muscle fiber from one side to the other

Acts as a calcium reservoir; it releases calcium through channels to activate contraction

Triad

a T tubule and two terminal cisterns associated with it

T Tubules

tubular infoldings of the sarcolemma which penetrate through the cell and emerge on the other side

Thick filaments

made of several hundred myosin molecules

Each molecule shaped like a golf club, Two chains intertwined to form a shaft-like tail, Double globular head

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Thin filaments

Fibrous (F) actin: two intertwined strands,

String of globular (G) actin subunits each with an active site that can bind to head of myosin molecule

Tropomyosin molecules Each blocking six or seven active sites on G actin subunits→Troponin molecule: small, calcium-binding protein on each tropomyosin molecule

Elastic filaments

Titin: huge, springy protein that makes elastic filament Run through core of thick filament and anchor it to Z disc and M line Help stabilize and position the thick filament Prevent overstretching and provide recoil

Contractile proteins

myosin and actin do the work of contraction

Regulatory proteins

tropomyosin and troponin Act like a switch that determines when fiber can (and cannot) contract

Dystrophin

clinically important protein Links actin in outermost myofilaments to membrane proteins that link to endomysium