Kinesiology exam #1

gamma motor neurons

stimulate the intrafusal fibers to contract, shortening the muscle spindle.

The appendicular skeleton

(bones of the upper and lower extremities) •UE: Scapula, clavicle, humerus, ulna, radius, carpals, metacarpals, and phalanges •LE: Pelvis, femur, tibia, fibula, tarsal bones, metatarsals, and phalanges

The axial skeleton

(skull, spinal column, sternum, and ribs)

Three factors that affect the stability of a joint are also related to its ROM:

1. Shape of articular surfaces. 2. Restraining effect of ligaments. 3. Muscles and tendons (single most important factor).

central nervous system

A. Brain B. Spinal cord

peripheral nervous system

A. Cranial nerves (12 pairs) B. Spinal nerves (31 pairs)

autonomic nervous system

A. Sympathetic B. Parasympthetic

Dendrites

Carry impulses toward cell body.

Labyrinthine system

Concerned with sense of balance. Consists of utricle, saccule, and semicircular canals. Filled with endolymph whose motion triggers hair cells. Contain otoliths that shift with gravity.

efferent fibers

Motor, outgoing

affarent fibers

Sensory, incoming

Insertion

The attachment of a muscle tendon to a moveable bone or the end opposite the origin usually more distal

brain stem

arousal and monitoring of physiological parameters, key facilitory and inhibitory centers.

origin

attachment of a muscle that remains relatively fixed during muscular contraction usually more proximal

spinal cord

contains cell bodies of lower motor neurons, common pathway between CNS & PNS, final point for integration and control.

synergists

cooperative muscle function

Contractility

is the ability to shorten and produce tension •a unique property possessed by muscle tissue only •The average muscle fiber can shorten to approximately ½ its resting length •It can be stretched until its approximately ½ again as long as its resting length

Cerebellum "little brain"

key role in sensory integration, regulates timing & intensity of muscle contraction.

reverse muscle action

occurs when the distal bone is stabilized and the proximal bone moves example: pull ups

countercurrent actions

one muscle shortens at both joints as the antagonist lengthens correspondingly and thereby gains tension at both ends. •In the hurdle jump above, a countercurrent muscle action occurs as the rectus femoris shortens concentrically at both joints while the hamstrings are stretched at both joints

basal ganglia

responsible for homeostasis, coordination & some learned acts of posture.

Interoceptors

sense heat, cold, pain and pressure. can be further subdivided into visceroceptors and proprioceptors

Joint receptors of the neck

sensitive to angle between the body and the head. Prevent labyrinthine proprioceptors from producing feeling of imbalance.

Semicircular canals

sensitive to angular acceleration. Three canals oriented in different planes at right angles to each other.

Utricle

sensitive to linear acceleration and head position with respect to gravity.

Ligamentous Joint

two bodies are tied together by ligaments, permits limited movement of no specific type. •Example: Coracoacrominal union & midunion of radius and ulna

all-or-none principle

•If the stimulus is of threshold value, all muscle fibers of the motor unit will contract. •applies only to individual motor units and not to entire muscles •The more motor units that contract, the greater will be the total strength developed

cerebral cortex

where consciousness occurs, initiation of voluntary movement.

isotonic contraction

• means "equal tension" - the tension remains constant while muscle shortens or lengthens.

STRUCTURAL CLASSIFICATION OF MUSCLES BY FIBER ARRANGEMENT: Bipennate

•A long central tendon with fibers extending diagonally in pairs from either side of the tendon. •Rectus femoris •Flexor hallucis longus tail feather

PROPRIOCEPTIVE REFLEXES: STRETCH REFLEX

•A reflex contraction of stretched muscle and synergists combined with the relaxation of antagonists.

•Tonic (Long latency) Response:

•A slow stretch (postural sway) •Sudden addition of weight to hand, elbow at 90°. •Biceps stretches, then contracts. •Movements that put muscles on a stretch in the backswing or preparatory phase can take advantage of the stretch reflex

reflex movement

•A specific pattern of response without volition/direction from the cerebrum. •Stimulus - receptor organ - sensory neuron - motor neuron - muscle (response) •Connector neurons often used.

mechanical axis of a bone

•A straight line that connects the midpoint of the joint at one end of a bone with the midpoint of the joint at the other end. •The axis may lie outside the shaft.

What is the Musculoskeletal Framework?

•An arrangement of bones and muscles •Adjacent bones are attached to one another by joints •Muscles that span the joints provide the force for moving the bones to which they are attached

Diarthrosis

•Articular cavity •Ligamentous capsule •Synovial membrane •Surfaces are smooth •Surfaces covered with cartilage •A joint in which there is a separation or articular cavity •Synovial fluid is secreted for lubricating the joint •Cartilage is usually hyaline but may also be fibrocartilage

factors responsible for joint stability

•Bony structure •Ligamentous arrangement •Muscle tension •Fascia •Atmospheric pressure •Proprioception •Neuromuscular control

saddle joint

•Both ends of the convex surface are tipped up, making the surface concave in the other direction •Has greater freedom of motion than the condyloid joint

Axons

•Carry impulses away from cell body.

hinge joint

•Constitutes movement in one plane about a single axis of motion

what is a lever?

•Defined as a rigid bar that turns about a fulcrum (fixed axis) when force is applied to it at a specific point •Anatomical lever: •A bone that engages in an angular or turning type of movement when a force is applied to it

Compact (Cortical bone)

•Dense layer of bone that makes up the outer layer of bone

MUSCLE PROPRIOCEPTORS: GOLGI TENDON ORGAN (GTO)

•Embedded "in series" in the tendon. •As tension in tendon increases GTO is activated. Signals CNS to relax muscle which is the opposite response that is seen in muscle spindles

angle of attachment

•If very shallow (muscle lies along the line of the bone), most of the tension will produce a force pulling along the bone. •Will tend to stabilize joint. •If fairly large, will have a much larger rotary component of force. •In many muscles the angle changes throughout ROM. •When muscle generates tension at a 900 angle to the bone, it is the most efficient at producing joint motion.

JOINT AND SKIN PROPRIOCEPTORS: RUFFINI ENDINGS

•In deep layers of skin and joint capsule. •Activated by mechanical deformation. •Stimulated strongly by sudden joint movement. •Sense joint position and changes in joint angle (as little as 2 degrees).

JOINT AND SKIN PROPRIOCEPTORS: PACINIAN CORPUSCLES

•In regions around joint capsules, ligament, and tendons sheaths. •End-organ has concentric layers of capsule. •Activated by joint angle changes & pressure. •Transmits impulses for only a very brief time.

isometric or static contraction

•Isometric means "equal length". •Tension is developed in the muscle without any appreciable change in length. •Occurs under two conditions: 1. Antagonistic muscles contract with equal strength. 2. Muscle is held against another force.

pivot joint

•Joint between atlas and axis (C1 & C2) or by two long bones fitting against each other near each end in such a way that one bone can roll around the other (radius & ulna) •Movement occurs in one plane about a single axis

MUSCLE PROPRIOCEPTORS: MUSCLE SPINDLES

•Located in muscle belly, parallel with fibers. •When stretched, sensory nerve sends impulses to CNS, which activates the motor neurons facilitating contraction of the same muscle.

JOINT AND SKIN PROPRIOCEPTORS: CUTANEOUS RECEPTORS

•Meissner corpuscles: touch •Pacinian corpuscles: pressure •Free nerve endings: pain

condyloid joint

•Movement can occur in two planes (forward and backward & side to side) •When these movements are performed sequentially, they constitute circumduction

line of pull

•Movement that the contracting muscle produces is determined by two factors: •Type of joint that is spans •The relation of the muscle's line of pull to the joint •Pectoralis major (clavicular) is primarily a flexor, but it also adducts the humerus (top photo). •When arm is abducted, line of pull moves above axis of rotation and contributes to abduction of humerus (bottom photo)

ballistic movements

•Movements that are initiated by vigorous contraction and completed by momentum. •Throwing, striking, & kicking

Synarthrosis

•No articular cavity, no capsule, synovial membrane or synovial fluid. •In two types, bones are united by cartilage or fibrous tissue. •Cartilaginous & fibrous •Third type, not a true joint, but is a ligamentous connection between bones. •Ligamentous

Cancellous (Trabecular bone)

•Open and spongy appearance •Allows for a relatively high strength-to-weight ratio

Epiphysis

•Part of a bone separated from the main bone by a layer of cartilage •Presence of cartilage indicates that the bone has not completed its growth •Cartilage is gradually ossified until closure is complete

plane joint

•Permits gliding movement; nonaxial

Phasic Response Application

•Phasic preparatory phase can take advantage of the stretch reflex. •Results in a stronger contraction. •Postural control feedback. •If the desired outcome is a strong application of force, the preparatory movement should be rapid (e.g. Think back to the Rookie of Year Video & the Box jump videos) •Pre-cocking phase of the overhead throw •Back swing of a golfer getting ready to drive off the tee •The crouch or sinking before the executing of a jump

EXTEROCEPTIVE REFLEXES: EXTENSOR THRUST REFLEX

•Pressure against the sole of the foot stimulates the Pacinian corpuscles in the subcutaneous tissue and elicits the reflex contraction of the extensor muscles of the lower extremity •When the weight is supported by the feet, the pressure from the floor is sufficient to bring about this reaction •As the weight is shifted to the balls of the foot, the pressure results in the extensor thrust reflex facilitating contractions of the extensor muscles of the legs and assists in the push-off from the floor

Osteogenesis

•Process of bone development

S.A.M.E.

•Sensory Afferent Motor Efferent •A comes before E; so it's logical that the sensory input must travel up towards the brain first prior to eliciting a motor response within a muscle

STRUCTURAL CLASSIFICATION OF MUSCLES BY FIBER ARRANGEMENT: Multipennate

•Several tendons are present, with fibers running diagonally between them. •Middle deltoid

ball and socket joint

•Similar to a swivel joint on a trailer hitch •Permits flexion & extension, abduction & adduction, circumduction, horizontal adduction & abduction, and rotation •Permits movement about three axes

concurrent actions

•Simultaneous flexion or extension of the hip and knee joints. •No net change in length of either muscle. •Think of it as the pull traveling up one muscle and down the other in a continuous circuit •In the soccer phot above, a concurrent muscle action of the rectus femoris on top of the thigh and the hamstrings on the underside of the thigh occurs when each of the antagonist muscles lengthens at one joint and shortens at the other

Tonic Response Application

•Slow preparatory phase should be used when the desired outcome is accuracy. •Result in a low level, sustained contraction. •Badminton low serve

Proprioceptors

•Stimulated by body movements. •Transmit information to CNS. •Two primary categories: •Muscle receptors •Joint & skin receptors •Located in muscles, tendons, joints, capsules, ligaments, fibrous membranes, and the labyrinth of the inner ear

Crossed Extensor Reflex

•Stimulus - flexor reflex or un-weighting •Response - opposite extensors contract for support. •Injury causes you to withdraw the involved limb while the opposite limb contracts to support the additional weight that is now placed upon it

Righting Reflex

•Stimulus - head not upright with respect to gravity. •Receptor - utricle and semicircular canals. •Response - bring the head to the upright position. •This reflex is integrated with movements of the arms and legs as described in the tonic neck andlabyrinthine reflexes. •The arm on the same side as the direction of the spin is thrust out during the spin •The opposite arm is thrust out at the termination of the spin

•Phasic (Short latency) Response

•Stimulus - high velocity stretch. •Response - facilitates proportional contraction of stretched muscle. •can be seen in the knee jerk •Reflexes of this type are extremely rapid and the contraction is of brief duration •The word "jerk" gives you an accurate picture of the response

Flexor (Nociceptive) Reflex

•Stimulus - pain, noxious stimuli. •Receptor - free nerve endings. •Response - Quick withdrawal from source of pain (flexion). •If a finger is pricked by a pin or if we inadvertently touch a hot surface, we do not have to decide to remove our hand from the painful surface •The natural jerk-back response occurs before we realize what has happened •The pain that we become aware of occurs after the withdrawal and plays no part in the reflex action itself.

articulations

•Structure and function of joints are so interrelated that it is difficult to discuss them separately. •The configuration of the bones that form an articulation, together with the reinforcing ligaments, determine and limit the movements of the joint.

Kinthesis

•The conscious awareness of position of body parts and the amount and rate of joint movement.

co-contraction

•The simultaneous contraction of movers and antagonists. •Neutralizers and stabilizers may need to cocontractto counteract the additional function of a mover.

stretch-shortening cycle

•The work done by the concentric contraction of muscle immediately following a pre-stretch is greater than that done by the muscles contracting from their resting length •The work done increases with the speed of the stretch •In the muscle-tendon complex, the tendons are most responsive to speed of stretch and provide the largest percentage of elastic energy release •Tendons are the prime providers of the SEC •The countermovement action common in the preparatory phase of many sport motions are an example of this •A fast squat before a jump, a rapid backswing before a serve, or a kick

eccentric contraction

•When a muscle slowly lengthens as it gives in to an external force that is greater than the contractile force it is exerting. •Muscle is acting as a "brake".

Reciprocal Inhibition

•When motor neurons are transmitting impulses to muscles, causing them to contract •Motor neurons that supply their antagonists are simultaneously and reciprocally inhibited •This results in the antagonist muscles to remain relaxed and the movers (agonists) contract without opposition

concentric contraction

•When tension by the muscle is sufficient to overcome a resistance and move the body segment of one attachment towards the other. •The muscle shortens.

STRUCTURAL CLASSIFICATION OF MUSCLES BY FIBER ARRANGEMENT: Pennate

•a series of short, parallel, feather like fibers extends diagonally from the side of a long tendon. •Tibialis posterior •Extensor digitorum longus

facilitation

•an excitatory stimulus

inhibition

•an inhibitory stimulus

Fast twitch fibers

•are large, pale, and have less blood supply than slow twitch fibers. •Two primary types are IIa (fast oxidative glycolitic) and IIb (fast glycolitic).

Slow twitch fibers

•are small, red, and have a rich blood supply, and greater myoglobin. •Highly efficient, do not fatigue easily.

flower spray endings (secondary sensory endings)

•at end of non-contractile midsection; one to five sensory endings. •Respond to static muscle length (tonic response).

primary endings

•coiled around non-contractile midsection. •Sensitive to velocity of change (phasic response). •Sharp decline in impulses with static length change.

movers or agonists

•directly responsible for producing a movement.

fibrous joints

•edges of bone are united by a thin layer of fibrous tissue, no movement permitted. •Example: Sutures of the skull

Extensibility and Elasticity

•enable the muscle to be stretched and return to normal length. •enable a muscle to be stretched like an elastic rubber band •When the stretching force is discontinued, the structure returns to its normal resting length

STRUCTURAL CLASSIFICATION OF MUSCLES BY FIBER ARRANGEMENT: Triangular

•fibers radiate from a narrow attachment at one end to a broad attachment at the other. •Pectoralis major

STRUCTURAL CLASSIFICATION OF MUSCLES BY FIBER ARRANGEMENT: Quadrate or Quadrilateral

•four sided and usually flat. •Consist of parallel fibers. •Rhomboids •Pronator quadratus

motor unit recruitment

•has an orderly sequence: •Smaller slow twitch fibers are recruited first. •They have lower thresholds •Larger fast twitch fibers are recruited later. •They have higher thresholds

antagonists

•have an effect opposite to that of movers, or agonists. •Check ballistic movements •First: Antagonists must relax to permit movement. •Second: Acts as a brake at completion of movement.

center of gravity

•imaginary point representing the weight center of an object •Point in a body about which all the parts exactly balance each other •The point at which the entire weight of the body may be considered concentrated •It's precise location in the human body depends on: •The individual's anatomical structure •Habitual standing posture •Current position •Whether external weights are being supported

STRUCTURAL CLASSIFICATION OF MUSCLES BY FIBER ARRANGEMENT: longitudinal

•long, strap like muscle with fibers in parallel to its long axis. •Sartorius •Rectus abominis

isokinetic contraction

•means "equal or same motion". •Maximum muscle effort at the same speed. •"Accommodating resistance".

active movements

•movement is produced by the subject's own muscular activity. •In slow movements muscular tension is maintained throughout ROM. (i.e. pushing heavy furniture across the room) •In rapid movements, tension could be maintained throughout ROM, but this is an inefficient way of performing.

Exteroceptors

•near body surface stimuli come from outside the body include the receptors of the five senses (sight, hearing, smell, taste, and touch)

passive movements

•no effort on the part of the subject involved, motion due to outside force. •are performed by another person (therapist, partner, etc.) •May also be caused by the force of gravity if the subject remained relaxed

neutralizers

•prevent undesired action •Muscle that acts to prevent an undesired action of one of the movers •i.e. If a muscle both flexes and abducts, but only flexion is desiredà an adductor contracts to prevent abduction of the mover

STRUCTURAL CLASSIFICATION OF MUSCLES BY FIBER ARRANGEMENT: Fusiform or Spindle-Shaped

•rounded muscle that tapers at either end. •Brachioradialis •Brachialis

Cartilaginous joint

•united by fibrocartilage permits bending & twisting motions. •Example: Articulations between the bodies of the vertebrae •Those united by hyaline cartilage permit only a slight compression (i.e. epiphyseal unions)