Chapter 1 - Structure and Function of Body Systems Flashcards
What 3 things are required in order to support the neuromuscular activity of the body
Oxygen
Nutrients
Removal of CO2
What does the musculoskeletal system made up of
Bones
Joints
Muscles
Tendons
What do muscles do
Function by pulling against bones that rotate about joints and transmit force to the environment
Muscles can only…
Pull
How many bones are in the body
206
What do bones provide
Support
Leverage
Protection
What does the axial skeleton consist of
Skull
Vertebral column
Ribs
Sternum
What does the appendicular skeleton consist of
Shoulder Girdle Arms Wrists Hands Pelvic girdle Legs Ankles Feet
What factor mostly affects skeletal growth
What does it cause to happen
When body is subjected to heavy loads
Bone will increase in density and bone mineral content
What other factors influence bone adaptations
Axial Skeletal being loaded
Frequency of loading
What are joints
Junctions between bones
What are fibrous joints
Example?
Allow virtually no movement
Sutures of the skull
What are carilaginous joints
Example?
Allow Limited Movement
Intervertebral disks
What are synovial joints
Example?
Allow considerable movement
Elbow and Knee
What are the important features of the synovial joints
Low friction
Large range of motion
Articulating bones consist of
Hyaline cartilage
Synovial fluid
Ligaments and cartilage
Uniaxial joints are
Hinge
Rotate about 1 axes
Elbow
Biaxial joints
Movement about two perpendicular axes
Ankle and Wrist
Multiaxial joints
Allow movement about all three axes
Shoulder and Hip
What are the different segments of the vertebral column in order
How many vertebral in each segment
Cervical - 7
Thoracic - 12
Lumbar - 5
Sacral - 5
What is epimysium
Connective tissue
Covers the body’s muscles
What is a tendon attached to
What is it
Bone Periosteum
Connective tissue covering all bones
Contraction of the muscle pulls on ______ which in turn pulls on _______
Tendon
Bone
Fasciculi is
A bundle of muscle fibers
Perimysium surrounds
Fasciculi
Muscle fibers are surrounded by
Endomysium
Sarcolemma
What is a motor unit
Motor neuron + muscle fibers
Myosin consists of
Globular head
Hinge point
Fibrous tail
Contractile unit of a skeletal muscle is known as ______
Sarcomere
The sarcomere is between two
Z lines
The A band consists of
Alignment of myosin filaments
The I band consists of
Area by Z line where there is only actin filaments
Actin colour is
Myosin colour is
Light
Dark
The Z Line is located in the middle of which band
I band
The H zone is located
In the middle of the sarcomere
Where only myosin is located
During contraction what happens to the H zone
Decreases as actin slides over myosin
During contraction what happens to the I band
Decreases as the Z lines are pulled towards the center of the sarcomere
Sarcoplasmic reticulum and T tubule connect to the myofibril and release what
Vesicles containing calcium ions
The calcium ions cause
An action potential and therefore a contraction
In stretched muscles, H zone and I bands are ______
Therefore, ________ force due to ________
Elongated
Low
Reduced crossbridge alignment
When muscles contract, H zone and I bands are ______
Therefore, ________ force due to ________
Shorten
High
Optimal crossbridge alignment
When muscle has contracted, H zone and I bands are ______
Therefore, ________ force due to ________
Shortened
Low
Overlapping of actin reduces potential crossbridge alignment
During resting phase there is
Low calcium levels
Low crossbridge formation
During contraction what chemical changes happen and what does it cause
Calcium is released from sarcoplasmic reticulum
Binds to troponin which shifts tropomyosin
Tropomyosin opens actin to be exposed to myosin
The amount of force produced in an instant is directly related to
The number of myosin crossbridges
Power stroke occurs when
ATP is hydrolysed
In order for the myosin head and actin to detach what is needed
Another ATP molcule
Relaxation occurs when
Stimulation of motor nerve stops
Calcium is pumped back into sarcoplasmic reticulum
What neurotransmitter travels across the neuromuscular junction
Acetylcholine
All or none principle states that
All muscle fibers contract simultaneously
A twitch is a
Muscle contraction
Tetanus of a motor unit is
Summation of muscle twitches with high frequency forms maximal contraction
Proprioceptors are located within
They detect
Joints
Muscles
Tendons
Pressure and tension
Muscle spindles are what type of receptors
They contain what kind of fibers
Proprioceptors
Intrafusal fibers and extrafusal fibers
Muscles spindles detect changes in
Muscle length
Rate of change in length
Golgi Tendon Organs (GTOs) detect
What do they do
Tension in the tendons
Inhibit muscle activation in order to protect against excessive tension
