CH. 1 Flashcards
Axial Skeleton
Skull, vertebral column, ribs and sternum
Appendicular Skeleton
Shoulder, pelvic girdle & bones in extremities
Fibrous joints
Allow virtually no movement (structures of the skull)
Cartilaginous joints
Allow limited movement (intervertebral disks)
Synovial joints
Allow considerable movement (knee, elbow)
Bone Periosteum
Specialized connective tissue that covers all bones that tendons attach to
Epimysium
Outer connective tissue surrounding the muscle
Perimysium
Middle connective tissue surrounding fasciculi (a bundle of muscle fibers)
Endomysium
Inner connective tissue surrounding each individual muscle muscle fiber and is contiguous with the muscle fiber’s membrane: Sarcolemma
Muscle fiber content
Sarcolemma (membrane)
Protein myofibrils
Additional protein
Stored glycogen
Fat particles
Enzymes
Mitochondria
Sarcoplasmic reticulum
Sarcomere
Smallest contractile unit in a muscle
Myofibrils
Composed of actin and myosin myofilaments that are organized longitudinally in the sarcomere
T tubules
Run perpendicular to the sarcoplasmic reticulum and terminate near the Z line between two sarcomeres. Contiguous with the Sarcolemma and deliver the signal from the motor neuron simultaneously to all depths of the muscle fiber
Sarcoplasmic Reticulum
Intricate system of tubules that surround each myofibril and contains calcium ions that regulate muscle contraction
A band
Alignment of myosin filaments
I Band
Contains actin filaments
Z line
Splits the I band and separates sarcomeres
H zone
Center of sarcomeres that contain myosin filaments
Motor unit (components)
Motor neuron
NM Junction
Corresponding muscle fibers
Motor neurons
Nerve cells responsible for innervating muscle fibers. 1 motor neuron can innervate up to thousands of muscle fibers
All or nothing principal
All muscles within a motor unit contract simultaneously when a motor unit delivers the signal to contract by the discharge of action potential. A stronger action potential CAN’T
produce a stronger muscle contraction
Action potential
Release of acetylcholine at nerve terminal. Diffuses across NM junction and excites the Sarcoplasmic reticulum/Sarcolemma and the fibers contract to merge and completely fuse
What are the 5 phases of the Sliding Filament Theory?
Resting phase
Excitation-Contraction Coupling phase
Contraction phase
Recharge phase
Relaxation Phase
Resting Phase
- Majority of calcium is stored in Sarcoplasmic reticulum
- Few myosin crossbridges are bound to actin
Vertebral Column
7 cervical vertebrae
12 thoracic vertebrae
5 lumbar vertebrae
5 sacral vertebrae
3-5 coccygeal
Excitation-Contraction Coupling Phase
-Nervous System signals the motor unit to contract
-Action Potential discharges across NM junction
-Calcium is released from Sarcoplasmic reticulum
-Calcium ions bind with troponin on actin
-H zone and I-Band shrink
-Z lines pull together as sarcomere shrinks
Contraction Phase
- ATP on the myosin crossbridge breaks down via hydrolysis, catalyzed by enzyme ATPase
- Breakdown of ATP to ADP and phosphate delivers the energy for the pulling action aka power stroke
Recharge Phase
- New ATP replaces ADP on the myosin crossbridge
- If calcium, ATP & ATPase are available, contraction repeats
Relaxation Phase
- Calcium pumped back into Sarcoplasmic Reticulum
- Actin and myosin return to unbound state
- Muscle Relaxes
Type I Fibers (slow twitch)
-Efficient
-Resistant to fatigue
-High capillary density/density of mitochondria
-High capacity for aerobic energy
-Low recruitment threshold (activated at lower demand unlike Type II)
-Limited potential for rapid Force development & anaerobic power
Type II Fibers
-Type IIa & IIx
-Inefficient and rapidly fatigue
-Capable of rapidly producing force for short periods of time
-Significant anaerobic power
-Type IIa have greater capacity for aerobic metabolism and more capillaries than Type IIx making them more resistant to fatigue
Postural Muscles
-Large composition of Type I fibers
-Needed throughout the day so endurance is required
-Example: Soleus
Prime Mover Muscles
-Include Type I and Type II fibers due to varying need
-Intensity of activity determines relative involvement of fiber types
-Example: Quadriceps group (involved in both low and high power activities)
2 ways muscle force is graded
- Frequency of motor unit activation (twitch)
- Increase in the total number of activated units (recruitment)
Tetanus
State of muscle activation where twitches are so frequent they merge together
How to improve muscle force production in athletes
- Incorporating phases of training with heavier loads
- Increasing muscle cross-sectional area through Resistance training
- Focusing on explosive, multi-muscle, multi-joint exercises
Proprioceptors
Specialized sensory receptors that provide the CNS with info regarding the position of body parts with respect to gravity
Muscle Spindles
-Modified intrafusal muscle fibers enclosed in a sheath of connective tissue running parallel to normal muscle fibers (extrafusal)
-Provide info concerning muscle length and rate of change in length
-Cause corresponding muscles to contract when stretched
-Indicate the degree of muscle activation needed to overcome resistance
-Increased spindle activation results in increased motor unit activation
Golgi Tendon Organs (GTOs)
-Located in tendons near myotendinous junction
-Attached end to end in series with extrafusal fibers
-Activate when tendon attached to an active muscle is stretched
-Discharge of GTOs increases as level of tension in muscle increases
-GTO discharge stimulates inhibitory neurons in the spinal cord, reducing tension in muscle
-Protects against excessive muscle tension and decreases muscle unit activation
R Side of heart
Pumps blood through the lungs for oxygenation
L side of heart
Pumps oxygenated blood throughout the body
Right atrium
Receives non-oxygenated blood from body
Right Ventricle
Pumps blood through the pulmonary circulation
Left atrium
Receives oxygenated blood from pulmonary circulation
Left ventricle
Pumps oxygenated blood through body
Atrioventricular Valves
Tricuspid and Mitral Valves that prevent backflow of blood from ventricles into atria during contraction (systole)
Semilunar Valves
Aortic and Pulmonary valves that prevent blood flow from aorta and pulmonary arteries during ventricular relaxation (diastole)
SA Node
Pacemaker of the heart, source of the rhythmic electrical impulses
AV node
Delays impulse from SA node to allow blood into ventricles
AV Bundles
-Conducts impulse to ventricles via left and right bundle branches— further branching into Purkinje fibers.
-transmits signals nearly simultaneously to left and right ventricles
Typical RHR
60-100 bpm
Bradycardia
Less than 60 bpm
Tachycardia
Over 100 bpm
Sympathetic Nervous system
Accelerates depolarization of SA node, increasing HR
Parasympathetic Nervous System
Decreases rate of depolarization, decreasing HR
P-wave
Electrical depolarization of the atria, which results in mechanical contraction
QRS Complex
Depolarization of ventricles
-Atrial repolarization masked by QRS complex
T-wave
Ventricular repolarization, resetting the heart between each beat
Hemoglobin
Iron-protein molecule that transports oxygen and buffers blood pH
Red blood cells
Contain hemoglobin and facilitates CO2 removal
Arteries
Large tubes that rapidly transport blood FROM the heart
-stiff walls to contain the high pressure of blood from the heart
Arterioles
Small tubes that branch off the arteries and control the blood before entering the capillaries
Capillaries
Smallest tubes that facilitate exchange of O2, CO2 and nutrients between blood and tissues
Venules
Collect blood from capillaries and transport it to veins
Veins
Larger tubes that return blood to heart
-thinner, dilatable walls that constrict or expand depending on current needs of the body
Respiratory System
Nasal Cavities
Trachea
Right & Left Bronchi
Bronchioles
Alveoli
Nasal cavities
Warm, purify, and humidify air entering the body
Trachea
1st generation respiratory passage
Right & Left Bronchi
2nd generation passages that split from trachea toward right & left lungs
Bronchioles
Additional 23 generations of passageways that deliver air to the alveoli
Alveoli
Location in lungs where gas exchange (diffusion) occurs nearly instantaneously
Inspiration
Diaphragm contracts, creating negative pressure in the lungs that pulls in air
Expiration
Diaphragm relaxes and elastic recoil in the lungs and chest cavity expels the air
Muscles involved in heavy breathing
Intercostals
Sternocleidomastoids
Anterior Serrati
Scaleni
Pleural Pressure
Pressure in the narrow space between lung pleura and chest wall pleura that is normally slightly negative
-Increases during and inspiration and decreases during expiration
Alveolar Pressure
Pressure inside the lung alveoli when the glottis is fully open and no airflow in or out of the lungs is occurring
-Increases during expiration and decreases during inspiration
