Chapter 1: Structure and Function of Body Systems Flashcards
Fill in the blanks: ( ) contains the hint.
The skeletal muscles are under the control of the a)________ (what part of the brain?), which activates the skeletal muscle cells or fibers through the b)_________ _________ (nerve cells) of the peripheral nervous system.
a) cerebral cortex
b) motor neurons
Fill in the blanks:
Support for neuromuscular activity involves continuous delivery of a)__________ and __________ to working tissues and removal of b)_________ and metabolic __________ from working tissues through activities of the c)___________ and ___________ systems.
a) oxygen; nutrients
b) carbon dioxide; waste by-products
c) cardiovascular; respiratory
Fill in the blanks:
The musculoskeletal system consists of a)__________, b)__________, c)__________ and d)__________.
a) bones
b) joints
c) muscles
d) tendons
True or False:
The muscles of the body ACT DIRECTLY to exert force on the ground or other objects.
FALSE.
The muscles of the body function by pulling against bones that rotate about joints which TRANSMITS FORCE TO THE ENVIRONMENT.
True or False:
Muscles can only push, not pull.
FALSE.
Muscles can only pull. But through the system of bony levers muscle pulling forces can be manifested as either pulling or pushing forces against external objects.
Approximately how many bones are in the human body?
206
Fill in the blanks:
Bones provide a)____________, b)____________ and c)____________.
a) leverage
b) support
c) protection
Fill in the blanks:
The axial skeleton consists of a)___________, b)___________, c)___________ and d)___________.
a) skull (cranium)
b) vertebral column (vertebra C1 through the coccyx)
c) ribs
d) sternum
Fill in the blanks:
The appendicular skeleton includes the a)___________, b)___________, c)___________ and d)___________.
a) shoulder (or pectoral) girdle (left and right scapula and clavicle)
b) bones of the arms, wrists and hands (left and right humerus, radius, ulna, carpals, metacarpals and phalanges)
c) the pelvic girdle (left and right coxal or innominate bones)
d) bones of the legs, ankles and feet (left and right femur, patella, tibia, fibula, tarsals, metatarsals, and phalanges)
Fill in the blank:
Junctions of bones are called _________.
Joints.
Fill in the blanks:
The 3 types of joints are a)_________, b)_________ and c)_________.
a) fibrous
b) cartilaginous
c) synovial
Name an example of a fibrous joint and how much movement it allows.
Sutures of the skull; allows virtually no movement.
Name an example of a cartilaginous joint and how much movement that joint allows.
Intervertebral discs; allows limited movement.
Name an example of a synovial joint and how much movement that joint allows.
Elbow and knee; allows considerable movement.
Sport and exercise movements occur mainly about which type of joints?
Synovial joints.
What are the two most important features of synovial joints.
- low friction
2. large range of motion
Fill in the blank:
Articulating bone ends in synovial joints are covered with smooth _________.
Hyaline cartilage
Fill in the blank:
The entire synovial joint is enclosed in a capsule filled with ____________ fluid.
Synovial
List the 3 categories of joints, the number of axes around which they rotate, and an example of each?
- uniaxial; 1 axis; elbow
- biaxial; 2 perpendicular axes; ankle/ wrist
- multiaxial; all 3 perpendicular axes that define space; shoulder and hip ball-and-socket joints.
True or False:
The knee is a true uniaxial hinge joint.
False.
The knee’s axis of rotation changes throughout the range of motion.
Fill in the blanks:
The a) _________ is made up of vertebral bones separated by flexible b) _________ that allow movement to occur.
a) vertebral column
b) discs
Name the 5 regions of the vertebral column.
- cervical
- thoracic
- lumbar
- sacral
- coccygeal
List the number of vertebrae in each of the 5 regions of the vertebral column.
- cervical
- thoracic
- lumbar
- sacral
- coccygeal
- 7 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral (fused together)
- 3 to 5 coccygeal
True or False:
When the body is subjected to heavy loads the bone will increase in density and bone mineral content.
True.
List factors that can affect skeletal growth in an adult.
- Frequency of loading the body (how often).
- Intensity of loading (how heavy).
- Type of loading (resistance training, explosive movements with impact, high intensity training, etc)
True or False:
There are several things that can positively affect the adult skeleton, and most are not a result of muscle use.
False.
Muscle use is one of the major things that positively affects the adult skeleton.
What do you call the connection point between bones?
Joint.
Fill in the blanks:
Each skeletal muscle is an organ that contains a)_________ tissue, b)_________ tissue, c)________ and d)_________.
a. muscle tissue
b. connective tissue
c. nerves
d. blood vessels
True or False:
Each skeletal muscle is an organ.
True.
What is the specialized connective tissue covering all bones?
Periosteum.
key to remembering: osteum means relating to bone.
What is the outermost layer of fibrous connective tissue covering the body’s more than 430 skeletal muscles?
Epimysium
key to remembering: epi- means upon or above
I remember epi- by thinking “Epi is epic. It’s big. It’s the outermost layer.”
True or False:
The epimysium is not contiguous with the tendons at the ends of the muscle.
False.
True or False:
Any contraction of a muscle (with a tendon) pulls on the tendon and in turn pulls on the bone.
True.
Limb muscles have 2 attachment sites to bone. The names given to these attachment sites describes the relative location of the attachments relative to the trunk. List the 2 names given to this relative location and describe where they are located.
- proximal attachments: located closer to the trunk
2. distal attachments: located farther from the trunk
Trunk muscles have 2 attachment sites to bone. The names given to these attachment sites describes the relative location of the attachments relative to the head and feet. List the 2 names given to this relative location and describe where they are located.
- superior: closer to the head
2. inferior: closer to the feet
Another name for muscle cells.
Muscle fibers
True or False:
A muscle fiber can have a diameter up to about the diameter of a human hair.
True
Fill in the blank:
The epimysium covers groups of bundled muscle fibers called ______________ that may consist of up to 150 fibers.
Fascicles
What is the name of the connective tissue that surrounds a fascicle?
Perimysium
key to remembering: peri- means about or around
I remember peri- by thinking “The peri- is around or about the middle.”
What is the name of the connective tissue that surrounds a muscle fiber?
Endomysium
key to remembering: endo- means ‘within’
I remember endo- by thinking “Endo is inside.” The deepest layer.
What is the membrane of a muscle fiber?
Sarcolemma
key to remembering: sarco- means flesh
-lemma means “to peel”
True or False:
All the connective tissue - epimysium, perimysium, and endomysium - is contiguous with the tendon, so tension developed in a muscle cell is transmitted to the tendon and the bone to which it is attached.
True
What is a motor neuron?
A motor neuron is a nerve cell.
Fill in the blank:
The junction between a motor neuron and the muscle fibers it innervates is called the ___________.
Neuromuscular junction.
True or False:
Each muscle cell can have multiple neuromuscular junctions.
False.
Each muscle cell has only one neuromuscular junction.
What is a motor unit?
A motor neuron and the muscle fibers it innervates.
True or False:
A single motor neuron innervates many muscle fibers, sometimes hundreds or even thousands.
True.
Fill in the blank:
A motor neuron and the muscle fibers it innervates are called a _________.
motor unit
What is the term for the cytoplasm of a muscle fiber that contains contractile components consisting of protein filaments, other proteins, stored glycogen and fat particles, enzymes, and specialized organelles such as mitochondria and the sarcoplasmic reticulum.
sarcoplasm
Fill in the blanks:
Hundreds of a)__________ dominate the sarcoplasm. b)___________ contain the apparatus that contracts the muscle cell, which consists primarily of two types of myofilament: c) _________ and d)________.
a) myofibrils
b) myofibrils
c) myosin
d) actin
Name the thick myofilament that contains a globular head, a hinge point, and a fibrous tail.
myosin
Name the thin myofilament that consists of two strands arranged in a double helix.
actin
Fill in the blank:
The arrangement of myosin (thick) and actin (thin) filaments gives skeletal muscle its ________ appearance.
striated
Fill in the blank:
The globular heads of the myosin filament protrude away from the filament at regular intervals, and a pair of myosin filaments forms a ___________, which interacts with actin.
cross-bridge
Name the smallest contractile unit of skeletal muscle.
sarcomere
Define sarcomere.
The smallest contractile unit of skeletal muscle.
True or False:
Myosin and actin filaments are organized latitudinally in the sarcomere.
False.
Myosin and actin are organized longitudinally.
Fill in the blank:
Adjacent myosin filaments anchor to each other at the ____________ in the center of the sarcomere (the center of the H zone).
M-Bridge
Key to remember. M is for myosin.
What is the M-Bridge?
The center of the sarcomere where adjacent myosin filaments anchor to each other.
Fill in the blank:
Actin filaments are aligned at both ends of the sarcomere and are anchored at the ___________.
Z-line
Key to remember. “Actin’ zany!”
What is the Z-line?
Where actin filaments anchor at both ends of the sarcomere.
Put the correct number in the blank:
______ actin filaments surround each myosin filament, and each actin filament is surrounded by _______ myosin filaments.
6;3
True or False:
It is the arrangement of the myosin and actin filaments and the Z-lines of the sarcomeres that gives skeletal muscle its alternating dark and light pattern, which appears striated under magnification.
True
Fill in the blank:
When looking at a detailed view of the myosin and actin filaments in muscle, the dark ________ corresponds with the alignment of the myosin filaments and contains both myosin and actin.
A-band
What is the A-band in a muscle?
The dark band that corresponds with the alignment of the myosin filaments in a muscle. The A-band contains both myosin and actin.
Fill in the blank:
When looking at a detailed view of the myosin and actin filaments in muscle, the light ________ corresponds with the areas in two adjacent sarcomeres that contain only actin filaments.
I-band (only actin)
Key to remembering: “I stand alone.” And associate actin as the outsider waiting to be pulled in by the myosin protein.
Fill in the blank:
The _______ is the area in the center of the sarcomere where only myosin filaments are present.
H-zone (only myosin)
True or False:
During muscle contraction, the H-zone decreases as the actin slides over the myosin towards the center of the sarcomere.
True.
Fill in the blank:
Parallel to and surrounding each myofibril is an intricate system of tubules, called _______________, which terminates as vesicles in the vicinity of Z-lines. Calcium ions are stored in the vesicles.
sarcoplasmic reticulum
True or False:
The regulation of calcium controls muscular contraction.
True
What controls muscular contraction?
The regulation of calcium.
What is an action potential?
An electrical nerve impulse.
What is the term for an electrical nerve impulse?
Action potential
Fill in the blank:
The discharge of an ____________ from a motor nerve signals the release of calcium from the sarcoplasmic reticulum into the myofibril causing tension development in muscle.
Action potential
Fill in the blanks:
The sliding-filament theory states that the a) _________ filaments at each end of the sarcomere slide inward on b)________ filaments, pulling the c)__________ toward the center of the sarcomere and thus shortening the muscle fiber.
a) acitn
b) myosin
c) Z-lines
True or False:
As acting filaments slide over myosin filaments, the H-zone shrinks while the I-band lengthens.
False
Both the H-zone and I-band shrink.
Fill in the blanks:
The action of a)___________ crossbridges pulling on the b)________ filaments is responsible for the movement of the c) _________ filament.
a) myosin
b) actin
c) actin
In what phase of the sliding-filament theory of muscular contraction is there very little calcium present in the myofibril where most of the calcium is stored in the sarcoplasmic reticulum so very few of the myosin crossbridges are bound to actin?
Resting phase
True or False:
The actin binding site is exposed after release of the stored calcium.
True
When the sarcoplasmic reticulum is stimulated to release calcium ions, the calcium binds to what protein that is situated at regular intervals along the actin filament and has a high affinity for calcium ions?
Troponin
When calcium ions bind to troponin, this causes a shift to what other protein which runs along the length of the actin filament in the groove of the double helix?
Tropomyosin
True or False:
The number of crossbridges that are formed between actin and myosin at any instant in time dictates the force production of a muscle.
True
Fill in the blanks:
Once the sarcoplasmic reticulum is stimulated to release calcium ions that bind to troponin which in turn causes a shift to the protein tropomyosin the a)_____________ now attaches much more rapidly to the b) ____________ filament which allows force to be produced as the
c) ________ filaments are pulled toward the center of the d) ________.
a) myosin crossbridge
b) actin
c) actin
d) sarcomere
EXTRA CREDIT: List 4 steps of the Excitation-Contraction Coupling Phase.
- sarcoplasmic reticulum is stimulated to release calcium ions
- calcium ions binds with the protein troponin that is situated at regular intervals along the actin filament.
- tropomyosin, which runs the length of the actin filament in the groove of the double helix, shifts
- the myosin crossbridge now attaches rapidly to the actin filament
Define ‘power stroke.’
Power stroke is the energy for pulling action of the myosin crossbridge on the actin filament.
What must occur in the contraction phase according to the sliding-filament theory of muscle contraction. What happens chemically?
The energy for the power stroke comes from: the hydrolysis (breakdown) of ATP to ADP and phosphate, a reaction catalyzed by the enzyme myosin adenosine triphosphatase (ATPase).
ATP must be broken down to ADP to begin the contraction.
What must occur in order for the muscle fiber to go back to it’s resting length?
Another molecule of ATP must replace the ADP on the myosin crossbridge globular head in order for the head to detach from the active actin site.
ATP must be present in order to relax the muscle.
Fill in the blanks:
a)_________ and b)___________ are necessary for crossbridge cycling with c)_________ and d)________ filaments.
a) Calcium
b) ATP
c) actin
d) myosin
List the 5 steps (on a molecular level) of muscle contraction.
- initiation of ATP splitting (by myosin ATPase) causes myosin head to be in an energized state
- release of phosphate from the ATP splitting process causes the myosin head to change shape and shift
- the actin filament is pulled toward the center of the sarcomere. ADP is released.
- Once ADP released the myosin head detaches from the actin but only after another ATP binds to the myosin head to facilitate detachment
- myosin head is read to bind to another actin
The cycle of muscle contraction continues so long as a)________ and b)_______ are present and c)__________ is bound to the d)________.
a) ATP
b) ATPase
c) calcium
d) troponin
What are the names of the 5 phases of muscle contraction?
- resting phase
- excitation-contraction coupling phase
- contraction phase
- recharge phase
- relaxation phase
True or False:
The relaxation phase of muscle contraction is brought about by the return of the actin and myosin filaments to their unbound state once calcium is pumped back into the sarcoplasmic reticulum which prevents the link between the actin and myosin filaments.
True.
Fill in the blanks:
Muscle fibers are innervated by a) ________________ that transmit impulses in the form of b)_____________ signals from the spinal cord to muscle.
a) motor neurons
b) electrochemical
True or False:
A motor neuron generally has one terminal branch at the end of its axon and innervates only one muscle fiber.
False:
A motor neuron has numerous terminal branches at the end of its axon and innervates many different muscle fibers.
True or False:
The extent of control of a muscle depends on the number of muscle fibers within each motor unit.
True
Fill in the blank:
When a motor neuron fires an impulse or _____________, all of that fibers that it serves are simultaneously activated and develop force.
action potential