chap 1 Flashcards
The axial skeleton consists of
skull, vertebral column, rib cage, sternum
Appendicular skeleton includes
shoulder girdle, pelvic girdle, extremities
fibrous joints
allow no movement
Catilaginous Joints
Allow limited movement
Synovial joints
Allow considerable movement
Example of Fibrous cartilaginous and synovial joints
Fibrous- sutures of skull
Cartilaginous- Intervertebral discs
Synovial joints- Elbow and Knee
Bone ends are covered with
hyaline cartilage
the entire joint is enclosed in a capsule filled with
synovial fluid
Uniaxial joints
Operate as a hinge, rotate about one
axis; Ex. elbow
Biaxial Joint
allow movement about two perpendicular axes (ankle and wrist)
multiaxial joint
ball and socket joints allowing movement in all 3 perpendicular axes.
Explain the Vertebral Column:
7 cervical verebrae in neck
12 thoracic in middle to upper back
5 lumbar making up lower back
5 sacral which are fused together
3-5 coccygeal
Each skeletal muscle is an organ that contains
muscle tissue, connective tissue, nerves, and blood vessels
what does fibrous connective tissue do and what are the types
covers bodys skeletal muscles
Epimysium Perimysium endomysium
Epimysium
surrounds entire muscle, Outer layer
Perimysium
The connective tissue that surrounds fascicles.
Endomysium
Connective tissue surrounding individual muscle fibers
Limb muscles have two attachments to bone which are
proximal (closer to the bone) and distal (farther from trunk)
motor neruon
Nerve cell
motor end plate or neuromuscular junction
Junction between motor neuron and the muscle fivers it innervates
Motor unit
A motor neuron and all of the muscle fibers it innervates
Sarcoplasm
cytoplasm of a muscle fiber, Contains protein filaments, stored glycogen, fat particles, enzymes, mitochondria and sarcoplasmic reticulum
myofibrils contain
the apparatus that contracts the muscle cell, conisting of myosin and actin
myosin (thick) and actin (thin) give muscle
its striated appearance
sarcomere
the smallest contractile unit of muscle
Myosin and actin filaments are organized
longitudinally in sarcomeres
action potential from a motor nerve signals
the release of calcium from SR into myofibril causing tension in muscle
sliding filament theory and phases
actin filaments at each end of sarcoere slide inward on myosin filaments, pulling z lines toward the center of the sarcomere and thus shortening the muscle fiber
Resting, excitation, contraction, recharge, relaxation
resting phase
Little calcium is present in the myofibril (most of it is stored in the sarcoplasmic reticulum) so very few myosin cross bridges are bound to actin
excitation-contraction coupling
When the SR is stimulated to release calcium ions, which bond with troponin, causing a shift to occur in tropomyosin, myosin crossbridge now attaches much more rapidly to actin filament
contraction phase
energy for pulling power stroke comes from hydrolysis (breakdown) of ATP to ADP
Recharge phase
Occurs as long as calcium is available in the myofibril, ATP is available to assist in uncoupling the myosin from the actin, and sufficient active myosin ATPase is available for catalyzing the breakdown of ATP
relaxation phase
Occurs when the stimulation of the motor nerve stops. Calcium is pumped back into the sarcoplasmic reticulum which prevents the link between the actin and myosin filaments
Contraction of a Myofibril
- (a) In stretched muscle the I-bands and H-zone are elongated, and there is low force potential due to reduced crossbridge-actin alignment.
- (b) When muscle contracts (here partially), the I-bands and H-zone are shortened.
- (c) With completely contracted muscle, there is low force potential due to reduced crossbridge-actin alignment.
Steps of muscle contraction
-initiation of atp splitting, causing myosin head to be energized allowing it to form a bond with actin
Myosin head changes shape and shifts, pulling the actin filament toward center of sarcomere (powerstroke) ADP is released Another ATP will bind to myosin head and head will detach from actin
Myosin head is ready to bond to another actin and cycle restarts
Extent of control of a muscle depends on
the number of fibers within each unit
action potential at nerve terminal causes
release of acetylcholine, once enough acetylcholine is released action potential is generated across sarcolemma and fiver contracts
precise muscle fibers may have as few as
one muscle fiber per motor neuron
muscles that require less precision may have
hundreds of fibers by one motor neuron
all-or-none principle
all of the muscle fibers in the motor unit contract and develop force at the same time. Cannot produce a stronger contraction and cannot only activate “some” of the fibers
Tetanus
the maximal amount of force a motor unit can develop
Type 1 fibers
Slow twitch efficient and fatigue resistant. great aerobic energy supply. Low force development potential
Type IIa fibers
Fast twitch Inefficient and fatigable as they have low aerobic power. rapid force and high ATPase activity
Type IIx fibers
fast twitch. Show less reistance to fatigue than type IIa
How can athletes improve force production?
Incorporate phases of training that use heavier loads in order to optimize neural recruitment.
Increase the cross-sectional area of muscles involved in the desired activity.
Perform multimuscle, multijoint exercises that can be done with more explosive actions to optimize fast-twitch muscle recruitment.
Proprioceptors
specialized sensory receptors that provide the central nervous system with information needed to maintain muscle tone and perform complex coordinated movements
Muscle Spindles
When a muscle is stretched the muscle spindle activates the sensory neuron, sends an impulse to the spinal cord, synapses with motor neuron causing muscle to contract
Golgi tendon organs
when an extremely heavy load is placed on muscle, discharge of GTO occurs
The sensory neuron of GTO activates an inhibitory interneuron in the spinal cord which in turn synapses with and inhibits a motor neuron serving the same muscle
Heart is made up of two pumps
Right ventricle- pumps blood to lungs
Left ventricle- pumps blood to rest of body
heart valves
open and close passively depending on pressure gradient
conduction system
Controls the mechanical contraction of the heart
trasmission of the cardiac impulse through the heart
SA node
AV node
AV bundle
Left and right bundle branches
PURKINJE FIBERS
electrocardiogram
Recorded at surface of body
Graphic representation of electrical activity of heart including Pwave QRS complex and T wave
P wave and QRS complex are recordings of
electrical depolarization
Pwave- Atria
QRS complex- ventricles
T wave
repolarization of ventricles
Blood vessels operate in what kind of circuit
closed
artial system does what
carries blood away from heart
venous system does what
returns blood toward heart
ateries
rapidly transport blood pump from heart
capillaries
exchange oxygen and other substances between blood and interstitial fluid throughout body
veins
collect blood from capillaries and gradually converge into larger veins which transport blood back to heart.
Hemoglobin
transports oxygen in the blood
What facilitates co2 removal
Red blood cells
cardiovascular system
transports nutrients and removes waste products while maintaining environment for body’s functions. blood transports o2 from lungs to tissues and co2 from tissues to lungs where it is removed.
Skeletal muscle pump
Assistance that contracting muscles provide to circulatory system. Contacting muscle compresses veins and blood flows in direction of valves back to heart.
air is distributed to the lungs by
trachea, bronchi, and bronchioles before air reaches alveoli where gasses are exchanged
movement of air and expired gases in and out of lungs are controlled by
expansion and recoil of lungs
expiration
diaphragm relaxes and abdominal structures compress lungs, expelling air
inspiration
contraction of diaphragm to create a vacuum in chest allowing air to be drawn into lungs
Primary function of the respiratory system
is to exchange oxygen and co2
with ventilation, oxygen diffuses
from alveoli into pulmonary blood and co2 diffuses from blood into alveoli
is it important to train respiration muscles
Regular exercise is good for maintaining respiratory muscle function
this can help preserve pulmonary function with aging
it is not necessary to specifically train muscles of respiration unless following surgery or prolonged bed rest
