SLS A&P Lecture ch10

How many muscles do we have?

600

All muscle contraction depends on what?

ATP

Which of the two main pathways of ATP synthesis requires a continual supply of oxygen?

Aerobic respiration

Which of the two main pathways of ATP synthesis yields more ATP?

Aerobic respiration

Muscle functions include heat production. How much of our body heat comes from muscles and from which muscles?

As much as 85% of our body heat by skeletal muscles

Muscle compartments are very snugly contained in their fasciae. If a blood vessel in a compartment is damaged by overuse or contusion (a bruising injury), what happens?

Blood and tissue fluid accumulate in the compartment. The inelastic fascia prevents the compartment from expanding to relieve the pressure. Mounting pressure triggers a sequence of degenerative events called compartment syndrome. Blood flow to compartment is obstructed by pressure on its arteries. If poor blow flow persists, nerves begin to die. After 6 hours, so does muscle tissue. Nerves can regenerate but muscle cannot. It is irreversible. Breakdown of muscle releases myoglobin into blood, causes dark urine. Treatment: rest limb and possible incision to release pressure.

What is the function of the infra hyoid group of muscles?

By fixing the hyoid from below they enable the suprahyoid muscles to open the mouth. They depresses the hyoid after it has been elevated, aids in singing high or low notes by elevating or depressing larynx

These muscles form rings around certain body openings. When they contract, they constrict the opening and tend to prevent the passage of material through it. Examples: orbiculares oculi of the eyelids and anal sphincters.

Circular muscles (sphincter)

Name a muscle in the deep perineal space and state a function of it.

Compressor urethrae, in females only, aids in urine retention.

Muscles are specialized for one major purpose. What is it?

Converting the chemical energy in ATP into the mechanical energy of. motion.

What is the role of the endomysium?

Creates room for blood capillaries and nerve fibers to reach every muscle fiber, ensuring that no muscle cell is without stimulation and nourishment.

What is the role of the digastric muscle in chewing and swallowing?

Depresses mandible opens mouth widely, elevates hyoid

The four pairs of muscles that produce the biting and chewing movements involve 5 actions. What are they?

Depression to ope the mouth for receiving food Elevation for biting off a piece of food or crushing it between the teeth Protraction. so that the incisors meet in cutting off a piece of food Retraction to draw the lower incisors behind the upper incisors and make the rear teeth meet lateral and medial excursion- the side to side movements that bring food

Explain what happens in rigor mortis?

Deteriorating sarcoplasmic reticulum releases Ca+2 which enters cytosol and activates myosin-actin cross-bridging Muscle contracts but cannot relax because relaxation requires ATP and ATP production is no longer produced after death; so fibers remain contracted until myofilaments begin to decay. Rigor mortis peaks about 12 hours after death, then diminishes over the next 48-60 hours.

How do the 3 pairs of pharyngeal constrictors work with swallowing?

During swallowing, they contract in order from superior to middle to inferior to drive food into the esophagus.

Describe the relationship of endomysium, perimysium and epimysium to each other.

Endomysium surrounds each muscle fiber. Perimysium wraps muscle fibers in bundles. Epimysium surrounds the entire muscle.

What muscles are used more often, the external intercostals or internal intercostals? Explain.

External intercostals: In expiration, the internal intercostals depress and retract the ribs expelling air but only in forceful expiration, not in relaxed breathing.

What is the sheet of connective tissue that separates neighboring muscles or muscle groups from each other and from the subcutaneous tissue called?

Fascia

These muscles are thick in the middle and tapered at each end. The biceps brachia of the arm and gastrocnemius of the alf are examples of this type.

Fusiform muscles

Explain Extensibility, a characteristic of muscles.

In order to contract, a muscle cell must also be extensible- able to stretch again between contractions. Most cells rupture if they are stretched even a little, but skeletal muscle cells can stretch to as much as 3x their contracted length.

A young thoracic surgery resident performing an operation for esophageal cancer accidentally severs the patient's left phrenic nerve. Predict the effect of this accident on the patient's respiration.

It would paralyze the left side of the diaphragm making breathing difficult.

Name a muscle in the pelvic diaphragm and state the function of it.

Levator ani: supports uterus, aids in falling away of the feces

Describe cardiac muscle in terms of: where is found, made up of, # of nuclei, involuntary/voluntary, striations/no striations

Limited to the heart cardiomyocytes are branched, shorter than skeletal Contain 1 nucleus intercalated discs join cardiomyocytes end to end striated involuntary

Describe smooth muscle in terms of: made up of, involuntary/voluntarymade up of, # of nuclei, involuntary/voluntary, striations/no striations

Made of fusiform myocytes lacking striations involuntary Most is visceral muscle-making up parts of walls of hollow organs, Cells are relatively short and have 1 central nucleus

Describe skeletal muscle in terms of: What it is made up of, attachments, number of nuclei, involuntary/voluntary,

Made of muscle fibers, long thin cells Most attach to bone Multiple nuclei striations, alternating dark and light bands Voluntary

Muscle functions include stability. Explain how.

Maintain posture by preventing unwanted movements antigravity muscle; prevent us from falling over Stabilize joints by maintaining tension

Muscle functions include movement. Explain the types of movements.

Move from place to place move body parts move body contents in breathing, circulation & digestion In communication, speech, writing, facial expressions and other nonverbal communications

What are the 5 functions of the three muscle groups?

Movement, stability, control of body openings and passages, heat production, glycemic control

Which one of the three pennate muscles generate more force than the others because they fit more muscle fibers into a given length of muscle?

Multipennate

Explain Contractility, a characteristic of muscles.

Muscle cells are unique in their ability to shorten substantially when stimulated. This enables them to pull on bones and other organs to create movement.

Muscle functions include glycemic control. Explain.

Muscles absorb and store glucose which helps regulate blood sugar concentration within normal range

These muscles have a fairly uniform width and parallel fascicles. Some are elongated straps such as the rectus abdomens of the abdomen, sartorial of the thigh and zygomaticus major of the face. Other are more squarish and are called quadrilateral. These muscles can span long distances and they shorten more than other muscle types.

Parallel

These muscles are feather-shaped. Their fascicles insert obliquely on a tendon that runs the length of the muscle, like the shaft of a feather.

Pennate muscle

What is the thicker connective tissue sheath that wraps muscle fibers together in bundles called fascicles?

Perimysium

What is the smooth ER that forms a network around each myofibril called?

Sarcoplasmic reticulum (SR)

What is the role of the mytohyoid in chewing and swallowing?

Spans mandible from side to side and forms floor of mouth; elevates floor of mouth in initial stage of swallowing

Muscle functions include control of openings and passageways. Explain

Sphincters; internal muscular rings that control the movement of food, blood and other materials within the body.

Explain conductivity, a characteristic of muscles.

Stimulation of a muscle cell produces more than a local effect. Local electrical excitation sets off a wave of excitation that travels rapidly along the cell and initiates processes leading to contraction.

Name a major superficial muscle and two major deep muscles of the back.

Superficial: trapezius or latissimus dorsi 2 major deep muscles: semispinalis thoracic, Quadratus lumborum

This is a muscle that aids the prime mover. Two or more of these acting on a joint can produce more power than a single larger muscle.

Synergist

How does a synergist, antagonist and fixator affect the action of a prime mover?

Synergist aids prime mover; antagonist opposes it. Fixator prevents a bone from moving, allowing another muscle attached to it to pull on something else.

What are tubular inholdings of the sarcolemma which penetrate through the cell and emerge on the other side called?

T tubules

What acts as a calcium reservoir and releases calcium through channels to activate contraction?

Terminal cisterns

What role do the intercostal muscles play in respiration?

The primary function of the intercostal muscles is to stiffen the thoracic cage during respiration so that it does not cave inward when the diaphragm descends. They also contribute to enlargement/contraction of the thoracic cage to add to the air volume that ventilates the lungs.

Define perineum

The surface region in both males and females between the pubic symphysis and the coccyx. The perineum is below the pelvic diaphragm and between the legs. It is a diamond-shaped area that includes the anus and, in females, the vagina.

What are the 3 kinds of myofilaments?

Thick, think and elastic

How do the infrahyoid muscles work in chewing and swallowing?

Thyrohyoid elevates larynx during swallowing so that its opening is sealed by a the epiglottis. The sternothyroid muscle the pulls down the larynx so you can resume breathing. The sternohyoid lowers the hyoid bone.

What is a T tubule and two terminal cisterns associated with it called?

Triad

These muscles are fan shaped, broad at one end and narrower at the other. Examples include the pectorals major in the chest and the temporals on the side of the head. Despite their small localized insertions on a bone, these muscles are relatively strong because they have a large number of fibers in the wider part.

Triangular (convergent) muscles

Explain how an inguinal hernia forms

Viscera protrude through a weak point in the muscular wall of the abdominopelvic cavity. When pressure rises in the abdominopelvic cavity, it can force part of the intestine or bladder into the canal or even the scrotum. Can occur when men hold their breath when lifting weights. These rarely occur in women.

Alice works out at a fitness center three times a week doing weight lifting and abdominal crunches. Martha prefers to sit on the sofa eating potato chips and watching tv. Both become pregnant. Other things being equal, give one reason why Alice may have an easier time with her childbirth than Martha will.

Voluntary contractions of the abdominal muscles aids the process of childbirth. Alice will be able to "push' more effectively due to the strength of her abdominal muscies. from her fitness routine more than the sedentary woman.

Why do humans have more expressive faces than other mammals?

We have a complex array of muscles that insert in the dermis and subcutaneous tissues.

Explain elasticity, a characteristic of muscles.

When a muscle cell is stretched and then released, it recoils to a shorter length. It if were not for this elastic recoil, resting muscles would be too slack.

Explain excitability (responsiveness) as part of the characteristics of a muscle.

When stimulated by chemical signals, stretch, and other stimuli, muscle cells respond with electrical changes across the plasma membrane.

How does the diaphragm control breathing?

When the diaphragm contracts, it flattens slightly and enlarges the thoracic cavity, causing air intake. The it relaxes, it rises and shrinks the thoracic cavity, expelling air.

Skeletal muscle never contracts unless it is stimulated by ________.

a nerve

What percentage of our body weight is attributed to muscles?

about 50%

The effect produced by a muscle, whether it is to produce or prevent a movement is called its ____________.

action

Two main pathways of ATP synthesis

anaerobic fermentation and aerobic respiration

A muscle that opposes the prime mover

antagonist

Define urogenital triangle

anterior half of the perineum

Which type of pennate muscle: fascicles approach the tendon from both sides. Example= rectus femurs of the thigh

bipennate

Name the muscle in the mental or buccal region that compresses cheek against teeth and gums; directs food between molars; retracts cheek from teeth when mouth is closing to prevent biting cheek; expels air and liquid from the mouth.

buccinator

What is the role of the perimysium?

carries the larger nerves and blood vessels as well as stretch receptors called muscle spindles.

What is the name of the movement of the head toward the opposite side, as when contraction of a muscle on the left turns the face toward the right?

contralateral

Name the muscle in the orbital/nasal region that draws eyebrows medially and downward in frowning and concentration; reduces glare of bright sunlight.

corrugated supercilli

What is the role of the geniohyoid muscle in chewing and swallowing?

depresses mandible, elevates and protracts hyoid

Name the muscle in the oral region that draws angle of mouth laterally and downward in opening mouth or sad expressions

depressor angle iris

Name the muscle in the oral region that draws lower lip downward and laterally in chewing and expressions of melancholy or doubt

depressor labii inferioris

Which of the muscles of respiration contracts in preparation for sneezing, coughing, crying, laughing and weight lifting, and compresses abdominal viscera and aids in childbirth and expulsion of urine and feces?

diaphragm

What are the muscles of respiration?

diaphragm , external intercostals, internal intercostals

Which of the suprahyoid group is an unusual muscle named for its two bellies; one which arises from the mastoid notch of the cranium and slopes downward and forward, the other arises from a trench on the inner surface of the mandibular body.

digastric

Several aspects of chewing, swallowing and vocalizing are aided by eight pairs of hyoid muscles associated with the hyoid bone. The supra hyoid group is composed of the four pairs superior to the hyoid. What are they?

digastric, geniohyoid, mylohyoid, and stylohyoid

Muscles have two forms of attachment to bones: ____ & ______

direct (fleshy) attachment indirect attachment

What is the role of the stytohyoid in chewing and swallowing?

elevates and retracts hyoid, elongates floor of mouth

What is the thin sleeve of loose connective tissue that surrounds each muscle fiber called?

endomysium

What is the fibrous sheath that surrounds the entire muscle called?

epimysium

What are the 5 universal characteristics of muscle?

excitability conductivity contractility extensibility elasticity

What are the muscles of the anterior abdominal wall?

external abdominal oblique, internal abdominal oblique, transverse abdominal, rectus abdominis

A muscle that acts upon a designated organ or region but arises from another region is called an _______________.

extrinsic muscle

muscle that prevents a bone from moving

fixator

Name the muscle in the scalp that elevates eyebrows in glancing upward and expressions of surprise or fright; draws scalp forward and wrinkles skin of forehead.

frontalis

Which muscle of the tongue and pharynx: unilateral action draws tongue to one side; bilateral action depresses midline of tongue or protrudes tongue

genioglossus

What is carbohydrate stored to provide energy for exercise called?

glycogen

Which muscle of the tongue and pharynx: depresses tongue

hyoglossus

The most common type of hernia is....

inguinal hernia

The nerve that supplies a given muscle is called its _____________.

innervation

Any muscle contained entirely within a region of interest is called an __________.

intrinsic muscle

What is the name of the movement of the head toward the same side as the muscle, as when contraction of a muscle on the left tilts the head to the left?

ipsilateral

Name a muscle in the superficial perineal space and state the function of it.

ischiocavernosus- Maintains erection of the penis or clitoris by forcing blood forward into its body

Name the muscle in the oral region that elevates angle of mouth as in smiling

levator anguli iris

Name the muscle in the oral region that elevates and everts upper lip in sad, sneering or serious expressions.

levator labii superioris

Name the muscle in the orbital/nasal region that elevates upper eyelid; opens eye

levator palpeerde superioris

Name the muscle in the mental or buccal region that elevates and protrudes lower lip in drinking, pouting, and expressions of doubt or disdain, elevates and wrinkles skin of chin

mentalis

These pennate muscles are shaped like a bunch of feathers with their quills converging on a simple point. Example: deltoid

multipennate

What are package groups of functionally related muscles called?

muscle compartments

A skeletal muscle consists of 4 things:

muscular tissue connective tissue nerves blood vessels

Muscle fibers have multiple flattened or sausage-shaped nuclei pressed against the inside of the sarcolemma. This unusual multinuclear condition results from the embryonic development of a muscle fiber- several stem cells call ________ fuse to produce each fiber, which each contribute one nucleus.

myoblast

What are the long protein cords occupying most of the sarcoplasm of a skeletal muscle fiber?

myofibrils

what is the red pigment that provides some oxygen needed for muscle activity?

myoglobin

The study of skeletal muscles is called

myology

Name the muscle in the orbital/nasal region that widens nostrils; narrow internal air passage between vestibule and nasal cavity

nasalis

A skeletal muscle cannot contract unless it is stimulated by a _______.

nerve fiber

Name the muscle in the scalp that retracts scalp; fixes galea aponeurotic so frontally can act on eyebrows.

occipitalis

What are the muscles in the infra hyoid group?

omohyoid, sternohyoid, thyrohyoid & sternothyroid

Name the muscle that encircles mouth, closes lips, protrudes lips as in kissing; uniquely developed in humans for speech

orbicularis iris

Name the muscle in the orbital/nasal region that closes eye in blinking, squinting and sleep, aids in flow of tears across eye, is the sphincter of the eyelids.

orbicularis oculi

Since Most muscles span at least one joint and attach to a different bone at each end, their contraction moves one bone relative to the other. The attachment at the stationary end is called the _____________ of the muscle and the attachment at the moving end is called the _________.

origin; insertion

ATP supply depends on availability of

oxygen and organic energy sources such as glucose and fatty acids

Which muscle of the tongue and pharynx: elevates root of tongue and closes oral cavity off from pharynx; forms palatoglossal arch at rear of oral cavity

palatoglossus

Name the muscle in the mental or buccal region that draws lower lip and angle of mouth downward in expressions of horror or surprise; may aid in opening mouth widely; tenses skin of the chin and neck.

platysma

Define Anal triangle

posterior half of the perineum

This is the muscle that produces most of the force during a particular joint action. Example; in flexing the elbow, it would be the brachialis.

prime move (agonist)

What is the hardening of muscles and stiffening of body beginning 3-4 hours after death called?

rigor mortis

Name the muscle in the oral region that draws angle of mouth laterally in expressions of laughing, horror or disdain

risorius

What is the plasma membrane of a muscle fiber called?

sarcolemma

The plasma membrane of a muscle fiber is called the _____________, and its cytoplasm is called the ___________________.

sarcolemma; sarcoplasm

What is the cytoplasm of a muscle fiber called?

sarcoplasm

Which type of muscle is a voluntary striated muscle that is usually attach to one or more bones?

skeletal muscle

The term muscular system refers to which type of muscle only?

skeletal muscles

What are the muscles of neck flexion?

sternocleidomastoid anterior, middle & posterior scalenes

Which one of the infra hyoid muscles is the only one with no connection to the hyoid bone?

sternothyroid

Which muscle of the tongue and pharynx: draws tongue upward ad posteriorly

styloglossus

What are the 3 pairs of pharyngeal constrictors that encircle the pharynx on its posterior and lateral sides, forming muscular funnel?

superior, middle and inferior pharyngeal constrictors

Four pairs of muscles produce biting and chewing movements of the mandible. All four of these muscles are innervated by the ______________ nerve

temporalis, masseter, medial pterygold & lateral pterygold trigeminal nerve

In an indirect muscle attachment, the muscle ends conspicuously short of its bony destination and the gap is bridged by a fibrous band or sheet called a _____________.

tendon

What are the dilated end sac of SR which cross the muscle fiber from one side to the other called?

terminal cisterns

Which of the infra hyoid muscles helps prevent choking?

throhyoid

What are the muscles of neck extension?

trapezius, selenium wapitis, selenium crevices, semispinalis wapitis and semispinalis cervicis

Which type of pennate muscle: all fascicles approach the tendon from one side. Example= palmar interosseous muscles of the hand

unipennate

What are the 3 types of pennate muscles?

unipennate, bipennate, multipennate

Name the muscle in the oral region that draws angle of mouth upward and laterally in laughing

zygomaticus major

Name the muscle in the oral region that elevates upper lip, exposes upper teeth in smiling or sneering

zygomaticus minor