CH 11 & 10 Flashcards
The partial contraction of a resting muscle is known as?
Muscle Tone
Which can be measured by attaching stimulating electrodes to a nerve-muscle preparation and a recording device?
Muscle Strength
Why are elastic elements important to muscle function?
They provide the recoil that helps return the sarcomere to its resting length
The minimum voltage necessary to generate a muscle twitch is called?
Threshold
From excitation through contraction, the SR does what?
releases AND reabsorbs calcium
What is a quick cycle of contraction in a whole muscle that occurs when a threshold level stimulus is reached?
Twitch
The tension generated by a muscle fiber depends on what?
How stretched or compressed the fiber is before its stimulated
What is muscle tone?
The partial contraction of resting muscles
On a myogram, the time between the stimulus and the twitch is known as?
the latent period
A record of the timing and strength of a muscle’s contraction is called?
a Myogram
The movement of an object or load results from the development of what kind of tension?
External tension
What is threshold, in regards to muscle physiology?
The minimum voltage necessary to generate a muscle twitch
As the myosin head releases the thin filament, muscle tension declines during what phase of muscle twitch?
Relaxation
True or false: A twitch is a sustained contraction in a whole muscle that occurs when a threshold level stimulus is reached.
FALSE. A twitch is not sustained, tetany refers to sustained muscle contraction
When an overly shortened or overly stretched muscle fiber is stimulated, what kind of contraction is generated?
A weak contraction
A muscle’s state of what affects the spacing between thick and thin filaments?
Hydration
How would high frequency stimuli at a constant voltage affect twitch strength?
It would increase
Stimulus frequency affects the sarcoplasmic concentration of what?
Calcium
What is it called when stimulus strength increases, increasing the number of motor neurons excited which, in turn, increases the number of motor units firing?
Multiple Motor Unit Summation
What produces incomplete tetanus?
Temporal Summation
You’re using an electrode that delivers a fixed discharge voltage. How could you generate a stronger twitch using this electrode?
Increase the frequency of the stimulation
A muscle fiber shortens and generates force during what period of muscle twitch?
Contraction
When lifting something heavy, which type of contraction occurs first?
Isometric
In what type of contraction does the internal tension build until it overcomes resistance and the muscle moves the load?
Isotonic
True or false: Recruitment occurs when more nerve fibers excite more motor units.
True
Aerobic Respiration utilizes what 2 molecule types as fuel to generate ATP?
Fatty acids and Glucose
Temporal summation leads to a state of fluttering contraction know as?
Incomplete tetanus
The continuous forceful contraction of a muscle with no relaxation betwen stimuli is?
Tetanus
What are the 2 most important pathways by which ATP is generated in muscle cells?
Anaerobic fermentation and aerobic respiration
What type of contraction maintains joint stability and posture?
Isometric
The type of muscle contraction in which there is a change in length, but no change in tension is called?
Isotonic contraction
In muscle, what does the source of ATP depend upon?
The duration of exercise
When a muscle is at rest, most of its ATP is generated by?
Aerobic respiration of fatty acids
During short bursts of intense activity, ATP for muscle contraction is supplied by what?
Creatine Phosphate
What process produces the most ATP?
Aerobic respiration
The glycogen-lactic acid system relies on which form of metabolism?
Anaerobic
When lifting something heavy, which type of contraction occurs first?
Isometric
The total supply of ATP and creatine phosphate in a muscle is enough to power contraction for how long?
1 minute
What provides long term energy for a cell?
Aeorbic Respiration
The glycogen-lactic acid system utilizes what molecules as fuel to generate ATP?
Glucose
In high-intensity short-duration exercise, what does muscle fatigue result from?
Increased potassium
What type of contraction involves the development of tension but no change in length?
Isometric
The accumulation of potassium during short-duration exercise has what effect on the membrane making the muscle fiber less excitable and contributing to fatigue?
It hyperpolarizes the membrane
Does lactic acid cause muscle fatigue?
No, lactic acid does not build up in the muscle fibers so it does not cause muscle fatigue
What is the maximum oxygen uptake?
the rate of uptake where increasing workload does not increase oxygen uptake
How is aerobic respiration important for producing energy long term?
By making ATP aerobically, fatigue is delayed, so long-term activity can continue
Why does increased oxygen consumption continue after exercise?
To replace the oxygen bound to myoglobin and hemoglobin
The progressive weakness and loss of contractility that results from prolonged use of the muscles is known as?
Muscle fatigue
Fibers that are well adapted to aerobic respiration are called what?
slow twitch fibers
The accumulation of what ions during short duration exercise lowers the membrane potential of the muscle and makes it less excitable?
Potassium ions
What 3 situation lead to fatigue in long duration exercise?
Electrolyte loss, Central fatigue, Fuel depletion
Which fibers are adapted for a quick response?
Fast Glycolytic (FG) fibers
During exercise, at which point does the rate of oxygen consumption plateua?
The maximum oxygen uptake rate
Skeletal muscles contain which muscle fiber types?
Both slow oxidative (SO) and Fast Glcolytic (FG) fibers
What function does increased oxygen consumption after exercise serve?
To allow the conversion of lactic acid to pyruvate and glucose by the liver
Why do larger muscles generate more strength?
because larger muscles have more contractile elements
What type of exercise improves fatigue resistance by enhancing the delivery and use of oxygen?
Endurance exercise
Which fibers contain a fast-acting ATPase and phosphagen enzymes?
Fast-twitch fibers
Cardiac and smooth muscle and both considered to be?
Involuntary
What appearance do muscles that contain mainly slow oxidative fibers have?
they are Red
Where is cardiac muscle found?
in the heart wall only
What are the thickened notched ends of cardiac muscle cells which contain gap junctions called?
Intercalated discs
Muscles with which fascicle arrangement produce the strongest contractions?
Pennate arrangements
Why are gap junctions important?
They allow the cells to contract in a coordinated fashion
Resistance exercise causes muscle growth by stimulating which of the following?
An increase in myofibril size
Which muscle type is resistant to fatigue, contracts with a regular rhythm, and functions 24 hours a day?
Cardiac muscle
The autonomic nervous system is important in the control of which two types of muscle tissue?
Smooth and Cardiac
What is the function of the cardiac pacemaker?
It triggers contraction in the heart muscle
Cardiac muscle cells contract rhythmically and independently. What is this called?
Autorhythmic
Describe cardiac muscle tissue
Striated, usually uninucleate, branching
What are the characteristics of cardiac muscle function?
It uses aerobic respiration almost exclusively, it has large stores of glycogen, and it is rich in myoglobin
Which structures coordinate contraction in cardiac muscle cells?
gap junctions
Describe smooth muscle tissue
uninucleate, non-striated, and fusiform shaped
What are the swellings along the length of a nerve fiber that innervates smooth muscle called?
Varicosities
In the heart, what triggers the wave of electrical excitation that causes the heart to contract?
the Pacemaker
What speed does smooth muscle contract and relax?
it is slow to contract and slow to react
What does it mean that cardiac cells are autorhymthic?
They contract rhythmically and independent of nervous stimulation
Functions of smooth muscle
Regulate pupil diameter, move material through the digestive tract, constrict or dilate blood vessels to control blood pressure
What is the function of intermediate filaments in smooth muscle cells?
they bind the dense bodies to the sarcolemma
What explains why cardiac muscle is resistant to fatigue?
because it uses little anaerobic fermentation
What type of smooth muscle is found in the digestive tract, respiratory tract, and urinary tract?
Single-unit
Which muscle tissue is capable of mitosis and hyperplasia?
Smooth muscle tissue
Excitation can be non-electrical in what type of muscle tissue?
Smooth
How do smooth muscle myocytes differ from cardiomyocytes?
Smooth muscle myocytes have no T tubules while cardiac muscles do
What regulatory protein is associated with the thick filament of smooth muscle and activates myosin light-chain kinase?
Calmodulin
What places are single-unit muscle found?
Wall of Uterus, wall of bladder, wall of stomach
What places are multi-unit smooth muscle found?
Piloerector muscle, iris of the eye
How does smooth muscle differ from skeletal muscle?
smooth muscle can be excited in a multitude of ways while skeletal muscle is excited by a neuron
What is the immediate trigger for the contraction of smooth muscle?
Calcium ions
What type of contraction of smooth muscle in blood vessels is important in maintaining blood pressure? This type of contraction is also important in keeping the intestine partially contracted
Tonic, continual contraction
What 2 types of muscle tissue can be autorhythmic?
Smooth and Cardiac
Which muscle tissue frequently exhibits tetanus and is resistant to fatigue?
Smooth
What is calmodulin?
It is a regulatory protein that replaces troponin in smooth muscle. It binds calcium and activates the enzyme myosin light-chain kinase, which adds a phosphate group to a small regulatory protein on the myosin head.
What would cause mechanically-regulated calcium gates in smooth muscle cells to open?
if the tissue was stretched
The sarcolemma of smooth muscle cells has pockets that contain calcium channels called what?
Caveolae
Does smooth muscle often fatigue?
No
What are the functions of skeletal muscle?
Heat production, control of body openings, and blood sugar regulation
Which surrounds the muscle fiber and creates room for nerve fibers?
The endomysium
Which describes the endomysium?
A loose connective tissue layer around each individual muscle cell
What are functions of skeletal muscle?
Joint stability, movement, heat production
Stretch receptors called muscle spindles are located within which connective tissue layer?
Perimysium
On its outer surface, the epimysium is continuous with which of the following?
Fascia
The epimysium is a connective tissue sheath that wraps around which of the following?
The entire muscle
What is fascia?
A thick sheet of connective tissue separating neighboring groups of muscle
A muscle that is thick in the middle and tapered at each end is classified as?
Fusiform muscle
The perimysium contains which of the following?
Muscle spindles, blood vessels, and nerves
A muscle of uniform width with fascicles aligned along its longitudinal axis would be classified as?
Parallel muscle
A muscle with its fasciculi arranged like barbs of a feather is called a?
Pennate muscle
Unipennate
All fascicles approach tendon from one side of the tendon
Bipennate
Fascicles insert on the tendon from both sides
Multipennate
Many bipennate muscle units merge onto one tendon
The rectus abdominis and the sartorius are examples of?
Parallel muscles
The pectoralis major and temporalis muscles are examples of?
Triangular muscle
Which describes a sphincter?
Circular muscle that forms a ring around a body opening
Which describes a pennate muscle?
Feather like fasciculi insert obliquely into the tendon
What are muscle compartments?
Functional groups of muscles surrounded by fascia
What are intermuscular septa?
Thick fasciae that separate muscles into compartments
The orbicular oculi muscle is an example of what muscle shape?
Circular
A muscle of uniform width with fascicles aligned along its longitudinal axis would be classified as?
Parallel
Which term refers to a broad, sheet-like tendon?
Aponeurosis
Which describes an extrinsic muscle?
A muscle that arises from one region, but acts upon a different region
The especially thick fasciae that separate the muscle compartments of the arm are known as ?
Intermuscular septa
In flexing the elbow, the prime mover is the?
Brachialis
The biceps brachii helps the brachialis flex the elbow. Which term best describes the role of the biceps brachii during elbow flexion?
Synergist
Which term refers to a muscle that opposes the prime mover?
Antagonist
What term refers to a muscle that prevents a bone from moving during an action?
A Fixator
What is an intrinsic muscle?
A muscle that is contained entirely within one region of the body
The nerve that supplies stimulation to a given muscle is called its?
Innervation
What is the term for a muscle that produces most of the force during a particular joint action?
Agonist (prime mover)
What is the term for a muscle that does not produce most of the force but works together with other muscles to produce movements?
Synergist
Functions of an antagonist during a joint action
Relaxes to allow other muscles to have control over the action, limits the speed or range of the action by opposing the other muscles involved
Blood capillaries are able to reach every muscle fiber because they run extensively through what?
the endomysium
What does the term ‘brevis’ mean in the name of a muscle?
short
The alveolar processes on the lateral surfaces of the mandible and maxilla are skeletal attachments for what muscle?
Buccinator
Are neck muscles innervated by cranial or spinal nerves?
Cranial nerves. Muscles below the neck are innervated by Spinal nerves
Functions of a synergist during joint action
Stabilize a joint to restrict undesirable movements of a bone, modify the direction of the movement produced by the prime mover, contract together with the prime move to produce more power
The muscular system at rest receives approx how much of the blood supply pumped by the heart?
one-quarter (3/4 during exercise)
Which muscle of facial expression attaches on the fascia of the deltoid and pectoralis major?
Platysma
What are the skeletal attachments of the buccinator?
Mandible and maxilla near alveolar margin, orbicularis oris and submucosa of cheek and lips
What is the muscle that attaches at the modiolus (angle) of the mouth and inserts in the tissue of the lips?
orbicularis oris
What is the action of the zygomaticus major?
draws the angle of the mouth upward and laterally
Attachment of the orbicularis oculi?
eyelids, skin around margin of orbit
Attachments of the levator palpebrae superioris
Lesser wing of sphenoid, upper eyelid
Attachments of orbicularis oris
Tissue of lips, modiolus at angle of mouth
Which muscle attaches to the lacrimal bone as well as to both the upper and lower eyelids?
Orbicularis Oculi
Describe the occipitofontalis
2 muscles connected together by a broad aponeurosis
Actions of the fontal belly of the occipitofrontalis
Elevates eyebrows, draws scalp forward, wrinkles skin of forehead
Action of the zygomaticus major
draws the angle of the mouth upward and laterally
Action of occipital belly of the occipitofrontalis
Retracts scalp. fixes galea aponeurotica
Name of the connective tissue sheet connecting the anterior and posterior muscles of the occipitofrontalis
Galea aponeurotica
Action of the orbicularis oculi
Closes the eye, aids in flow of tears across eye
Complex of muscles that encircles the mouth
Orbicularis oris
Which muscles elevates and wrinkles the skin of the chin?
Mentalis
Which muscle compresses the cheek?
Buccinator
The genioglossus, hyoglossus, styloglossus, and palatoglossus all act on what?
the Tongue
Which is a large triangular (convergent) muscle located on the side of the head?
Temporalis
Which muscle draws the lower lip and angle of the mouth downward and may also help open the mouth widely?
Platysma
Styloglossus, Genioglossus, Palatoglossus, and Hyoglossus of the tongue are all extrinsic or intrinsic muscles?
Extrinsic muscles of the tongue
What is the primary action of the temporalis?
elevates mandible
The temporalis, masseter, and the pterygoid muscles produce which type of movements?
Chewing
Parallel muscle located in the jaw?
Masseter
The omohyoid and thyrohyoid muscles are part of which muscle group?
Infrahyoid muscles
The three pairs of pharyngeal constrictors play a role in which action?
swallowing
A thin superficial muscle of the upper chest and lower face?
Platysma
Geniohyoid, Mylohyoid, and Stylohoid are infrahyoid or suprahyoid muscles?
Suprahyoid
The muscle that attaches on the back of the skull and the spinous processes of vertebrae C7-T12 and also attaches on the scapula and clavicle is the?
Trapezius
Which muscles produce biting and chewing movements of the mandible?
Temporalis, Masseter, Medial pterygoid, Lateral pterygoid muscles
Bilateral contraction of the sternocleidomastoid produces what action?
Draws head straight forward and down
The manubrium, clavicle, and mastoid process are skeletal attachments of what?
Sternocleidomastoid
The flexors of the neck
Sternocleidomastoid and scalenes
The scalene muscles attach where?
All cervical vertebrae and ribs 1 and 2
The trapezius, splenius muscles, and semispinalis muscles are classified as what?
Extensors of the Neck
Which is a large diamond-shaped muscle that extends from the neck, over the shoulders, and halfway down the back?
Trapezius
What muscle extends and laterally flexes the neck?
Trapezius
The sternocleidomastoid and scalenes are classified as what?
Flexors of the neck
The diaphragm and intercostal muscles are classified as what?
Muscles of respiration
Unilateral contraction of the scalene muscles can cause which actions?
Contra lateral neck rotation and ipsilateral neck flexion
What is the diaphragm?
Muscular dome between the thoracic and abdominal cavities
The muscle that is innervated by the phrenic nerves is the ?
Diaphragm
The external intercostal muscles do what during respiration?
Elevate and protract the ribs
What are the skeletal attachments of the external abdominal oblique?
Iliac crest, pubic symphysis, superior margin of pubis
Outer surface of ribs 5-12
The rectus abdominis, transverse abdominal, and abdominal oblique muscles are are all located in which part of the body?
Anterior abdominal wall
The abdominal oblique muscle that compresses abdominal contents and, when only one side contracts (unilateral contraction), causes ipsilateral rotation of the waist is the ?
Internal abdominal oblique
The abdominal oblique muscle that originates on ribs 5-12 is the ?
External abdominal oblique
The transverse abdominal attaches to ?
Costal cartilages 7-12, thoracolumbar fascia, inguinal ligament, iliac crest
Which muscle originates on the pubic symphysis and superior margin of the pubis and attaches on the xiphoid process and costal cartilages 5-7?
Rectus abdominis
What muscle do you contract in order to straighten your back after bending at the waist?
Erector spinae
Which are major deep muscles of the back?
Quadratus lumborum and semispinalis thoracis
The abdominal oblique muscle that compresses abdominal contents and, when only one side contracts (unilateral contraction), causes ipsilateral rotation of the waist is the?
Internal abdominal oblique
Which term refers to the diamond-shaped area between the thighs that is bordered by the pubic symphysis, the coccyx, and the ischial tuberosities?
Perineum
Together what muscle do the iliocostalis, the longissimus, and the spinalis form?
the Erector spinae
What is the action of the ischiocavernosus?
Compresses base of penis or clitoris maintaining erection
What is the major deep muscle in the thoracic region?
Semispinalis thoracis
What muscles are located in the deep perineal space?
Deep transverse perineal and compressor urethrae
What abdominal oblique muscle inserts on ribs 10-12, the costal cartilages 7-10, and the pubis?
Internal oblique
What muscle compresses the anal canal, supports the uterus and other pelvic viscera, and aids in the falling away of the feces?
Levator ani
What muscle is found only in females in the perineal space?
Compressor urethrae
What is the action of the pectoralis minor?
Moves scapula laterally and forward
What is the anterior skeletal attachment of the serratus anterior?
All or nearly all ribs
Which triangular muscle, located in the upper part of the chest, arises by three heads from ribs 3 to 5 and converges on the shoulder? Pectoralis major or minor?
Minor
Which muscle spans most of the pelvic outlet and forms the floor of the true pelvis?
Levator ani
Which muscle works with the pectoralis minor to draw the scapula laterally and forward around the chest wall, and acts as the prime mover in all forward-reaching and pushing actions?
Serratus anterior
What region is the pectoralis major located?
Upper chest or mammary region
Which muscle is classified as both a neck extensor and a posterior shoulder muscle?
Trapezius
Actions of the levator spaculae?
Retracts scapula, elevates scapula, and laterally flexes neck
Which muscle flexes, adducts, and medially rotates the humerus?
Pectoralis major
Which muscle adducts and medially rotates the humerus, extends the shoulder, produces backward swing of the arm, and pulls the body forward and upward as in climbing?
Latissimus dorsi
What is the prime mover of elbow flexion?
Brachialis
Muscle that causes rapid supination of forearm is?
Biceps brachii
Which muscle extends the knee, laterally rotates the tibia, aids in abduction and medial rotation of the femur, and tautens the iliotibial tract to brace the knee when the opposite foot is lifted?
Tensor Fasciae latae
