Unit I Flashcards
Myology is the study of
muscles
Roughly what percentage is muscle of total body weight?
40-50%
The specific function of skeletal muscle is to
create voluntary movement
What are the 5 main functions of skeletal muscle in general though?
- movement
- stability
- communication
- control of body openings and passages
- heat production
What is the basic structural unit of a muscle?
the muscle fiber
What is a fasciculi?
groups of muscles fibers in a bundle
how are fasciculi and fibers bound together?
via connective tissue
Describe endomysium
inner most layer of connective tissue
it surrounds each muscle fiber and connects adjacent ones
Describe endomysium
middle layer of connective tissue
surrounds each fasciucli and compartmentalizes muscle
Describe epimysium
the outer most layer
surrounds entire muscle and separates it from surrounding organs
continuous with deep fascia and will become tendon
Describe the nuclei of muscle fibers
long and multinucleated and located around periphery of fiber
Explain hypertrophy
increase in size of muscle due to increase in size of each muscle fiber
Explain hyperplasia
increase of muscle size due to increase in number of muscle fibers.
What causes hyperplasia?
muscle is subjected to high resistance exercise inducing injury and followed by a regenerative process
What is the sarcoplasm of a muscle?
the cytoplasm.
Type I muscle fibers are best suited for what sorts of activities?
in where long sustained contraction is required, like endurance activites.
What type of metabolism are Type I fibers associated with?
aerobic metabolim
Type II muscle fibers are best suited what sort of activites?
quick powerful activities that require speed and strength.
What type of metabolism are Type II fibers associated with?
anaerobic metabolism
Between Type I and Type II which has more sarcoplasm and myoglobin?
Type I
Do Type I fibers have minimal capillary beds?
No they actually have extensive capillary beds
Is type I or type II fast twitch?
type II
Does Type II possess fatigue resistance?
not really. Type I is more suited for fatigue resistance
Between Type I and Type II which has the most mitochondria?
Type I
Do type I fibers have more glycogen/less fatty acids?
no, type II does. Type I has the opposite.
Which fiber type, I or II, atrophies with aging?
type II. Type I atrophies with immobilization
Describe intermediate fibers
they exhibit characteristics of having both type I and type II fibers
they contract faster than type I but slower than II
greater resistance to fatigue but histologically similar to type II
The sarcolema is the ______?
cell membrane
Define sarcoplasmic reticulum
tubular system which stores calcium and transports it to myofibrils
Define transverse tubules
tubular invaginations of the sarcolemma which pass nerve impulses to muscles and myofibrils
Define myoglobin
a red protein pigment in the sarcoplasm that stores oxygen in the muscles and has a higher affinity for oxygen than hemoglobin
Myofibrils are the__________
contractile apparatus of the muscle fibers
myofibrils are formed from
thick and thin fibers known as myofilaments
I-bands are described as
the dark areas
A bands are described as
the light areas
H bands are described as
the light areas in the middle of each dark band
M bands are described as
the think dark like in the middle H bands
Z lines are described as
the think dark lines in the middle of I bands
what is the smallest functional unit of the muscle and where does it start and end?
the sarcomere. it runs from z line to z line
Actin is found where and can be desribed as what?
its found in I bands and is thin
Mysoin is found where and can be described as what?
its found in A bands and is thick
Name the two regulatory proteins in muscles
troponin and tropomysoin
What allows troponin and tropomysoin to interact with their respective muscle proteins?
calcium
Describe how calcium allows the regulatory proteins to interact
it gets rid of the inhibition caused by the proteins which allows contraction
When a nerve impulse reaches the T-tubules where is calcium released from?
the sarcoplasmic reticulum
What is troponin located on?
actin
what happens to troponin once calcium reaches it?
calcium binds to it and causes a change in the shape of tropomysoin
what is tropomyosin located on?
mysoin
what does the change in shape of tropomyosin do?
it moves the molecule aside and exposes the myosin binding site on actin so the two proteins can interact and contract
Where does the aerobic pathway take place and what does it produce?
it takes place in the mitochondria and produces ATP
What does the aerobic pathway prefer to make ATP?
fatty acids from triglycerides
What form does excess ATP created take?
the form of heat
What substances does the anaerobic pathway depend on?
creatine phosphate and glycogen
which substances is used first in the anaerobic pathway?
creatine phosphate
what about the second substance used in anaerobic metabolism?
glycogen
what process is used to make ATP from glycogen?
glycolysis
Where in the body is glycogen stored?
muscle and liver cells
what is the by-product of glycolysis that is the cause of the pathway being so short?
lactic acid
From a metabolic POV of exercise describe phase one
within the first few minutes creatine phosphate and glycogen are the main fuel sources. up to 20% of stored muscle glycogen may be used during this time
From a metabolic POV of exercise describe phase two
metabolism shifts to the use of aerobic pathways and fatty acids to make ATP
From a metabolic POV of exercise describe phase three
as exercise intensifies metabolism shifts back to anaerobic pathways and uses up the remaining glycogen. its here the lactic acid builds up
Describe carbohydrate/glycogen loading
a diet trick that increases the store of glycogen in muscles
Describe Day one of carb loading
work to exhaustion to deplete glycogen stores
Describe day 2-4 of carb loading
continue exercise and eat meals high in fat and protein, and low in carbs
Describe day 5-7 of carb loading
no exercise and eat meals high in carbs
What is the theory behind carb loading?
its that the body thinks that there is a problem with glycogen storing and begins storing more glycogen than normal
What are some reported side effects of carb loading?
light headedness, impairment of mental acuity, and for every stored gram of glycogen 3 grams of water accompany it.
How many cups of coffee may help an endurance athlete in a competition?
about two cups an hour before their competition
What effect does the caffeine in the coffee have?
it may help burn fatty acids better and increase calcium permeability
How does the better burning of fatty acids from the use of caffeine have an impact?
it should delay the use of glycogen
What is limit set by the IOC for the use of caffeine?
1000mg
Describe induced erythrocythemia/blood doping
by increasing the amount of RBC’s one can increase their oxygen carrying capacity which can increase their endurancecpacity
What are some risks of blood doping?
rash, fever, acute hemolysis, transmission of viruses, and kidney damage due to fluid overload
What is erythropoietin and what is it used for?
its a natural hormone made by the kidneys that helps make RBC’s. but it can be synthesized to use for blood doping or for anemics
What is the main danger of erythropoietin?
it can thicken blood to lethal levels
What are anabolic steroids and their use?
a synthetic form of testosterone that attempts to utilize the anabolic effects with minimal androgenic effects
what does anabolic mean?
the stimulation of protein synthesis
what does androgenic mean?
development of secondary sexual characteristics
Describe the oil based form of steroids
an injection with fewer side effects but is detectable for several months in the body
Describe the water based form of steroids
pill form, has more side effects, and is cleared from the body in 3-4 weeks
What does the term stacking mean when referring to steroids?
taking several forms of steroids
What does pyramiding mean when using steroids?
begin using low doses then ascend to a peak and taper off
What is the typical time cycle of steroid use?
6-8 weeks
List some of the short term side effects of steroid use
headaches, back acne, testicle shrinkage, aggressiveness, gynecomastia, and tendon damage.
List some long term side effects of steroid use
cardiovascular issues, GI issues, the reproductive system, and endocrine system are affected
List short term side effects in women who use steroids
larger clitoris, smaller mammary glands, facial hair, deeper voice, tendon damage, and better androgenic effects
How do steroids physiologically work
they increase the amount of growth hormones, and activate protein synthesis, while inhibiting protein breakdown
What are some clinical reasons to prescribe steroids?
restore hormonal levels, improve mood, increase appetite, and body weight in terminally ill patients
What is the chemical composition of a muscle?
75% water, 20% protein, 5% others
Will a single muscle fiber contract by itself?
no, instead several fibers will contract at the same time
Describe a motor unit
a nerve fiber and the group of muscle fibers it supplies
What is the smallest part of muscle that can contract by itself?
the motor unit
What makes a contraction stronger?
the number of motor units being contracted at once
What makes a motor unit capable of precise control?
having a smaller amount of motor fibers
What portions does a neuromuscular junction possess?
presynaptic, postsynaptic, and synaptic cleft.
What is the presynaptic portion of a neuromuscluar junction?
the nerve ending
What is the postsynaptic portion a a neuromuscular junction?
the sarcolemma of a muscle fiber
what is the synaptic cleft of a neuromuscular junction?
the space between post and pre synaptic portions
Desribce how a nerve impulse makes it’s way across a neuromuscular junction
when a nerve impulse reaches the presynaptic portion acetylcholine is released and diffuses across the cleft to bind on to receptors of the postsynaptic portion.
Describe what happens once the nerve impulse has reached the postsynaptic portion
Once acetylcholine has binded, an action potential is sent down the T-tubules allow muscle proteins to contract.
What breaks down acetylcholine from the binding site?
acetylcholinesterease
What is myasthenia gravis?
a common autoimmune disorder in which the ACH receptor sites are destroyed by abnormal antibodies that leads to the atrophy of T-tubules
Is myasthenia gravis genetic?
no
What does myasthenia gravis affect first?
cranial nerves and progresses to the extremities
what gland is commonly affected by those who have myasthenia gravis?
the thymus gland is enlarged or tumorous
What is transitional neonatal myasthenia gravis?
a 25% chance of a mother passing abnormal antibodies to the fetus thru the placenta
What effect does nicotine have on ACH?
it binds to receptor sites instead of ACH, and because nicotine cant be degraded by ACHe it creates a more prolonged action potential
What effect does snake venom have?
it prevents ACH from from binding to receptors and prevents action potentials from occurring
what effect does organophosphate have?
it inactivates ACHe meaning ACH builds up at the postsynaptic portion causing muscles to stay contracted
What effect does botulin toxin have?
it blocks ACH from being released from the presynaptic portion
Which bacteria releases botulin?
clostridium botulinum
Define proprioception
conscious awareness of the orientation of the body and its parts
What happens when one loses proprioception?
a loss of conscious and unconscious information as to what the muscles are doing and where they are in space resulting in uncoordinated movement
What are proprioceptors?
sense organs in the musculoskeletal system
Describe muscle spindles
fluid filled sacs that detect stretch in muscles
What are intrafusal muscle fibers located in and what innervates them?
they are in muscle spindles and both afferent and efferent innervate them
what are extrafusal muscle fibers associated with?
efferent nerve fibers
Describe golgi tendon organs
they are in tendons and trigger a reflex to inhibit muscle contractions that could cause injury
Define tensile strength
the load necessary to rupture a given material when pulled in the direction of its length
List some advantages of tendons
improve leverage, small and size and maintain limb conformity, act as a shock absorber, and flexible
What is an avulsion fracture?
the tendon pulls a piece of bone out
What types of injuries can cause avulsion fractures?
traction injuries
What type of innervation do tendons have?
only afferent
What is the function of bursa?
to act as a lubricating device between a tendon and another structure.
Describe the fusiform/parallel arrangement of muscle fibers
fibers run parallel to the long axis
Describe the arrangement of unipennate muscle fibers
fibers run obliquely
describe the arrangement of bipennate muscle fibers
tendon lies in the center and fibers run to it from each side
What arrangement do endurance (type I) muscle fibers have?
typically pennate
what arrangement do power and speed (type II) fibers have?
typically parallel/fusiform
Muscles that are responsible for carrying out a particular movement
primer move/agonist
assits prime mover, gives more force to a movement, stabilizes a joint,or keeps a bone of originof the mover steady
synergist
muscle that produces the opposite effect of the agonist
antagonist
Define reciprical innervation
when a muscle contracts its antagonist relaxes
Cofreflex phenomenon
both agonist and antagonist contract
A pathology of the CNS
ALS
what affect does ALS have?
both upper and lower motor neurons are destroyed
A pathology of the PNS
Guillan-Barre syndrome
What affect does Guillan-Barre syndrome have?
it demyelinates the PNS
A pathology of the neuromuscular junction
myasthenia gravis, botulism,and meurotoxins
A pathology of muscle fibers
muscular dystrophy, duschanne disorder
When a muscle remains in a contracted state for a longtime that can sometimes be permanent it is called
contracture
What helps to some degree with muscle regeneration?
satellite cells
where are satellite cells located?
between the endomysium and sarcolemma
What pathology prevents satellite cells from their function?
muscular dystrophy
What comprises the upper extremity?
the shoulder girdle and free limb
What comprises the shoulder girdle?
the scapula and clavicle
What makes the free limb?
the arm, forearm, and hand
Describe intramembranous ossification
bone cells replace mesenchyme
Describe endochondral ossification
bone cells replace hyaline cartilage
What is the first bone to undergo ossification?
the clavicle usually around the 5th-6th week of development
How many ossification centers does the clavicle have?
two
The centers appear near the center of the bone around when?
5th-6th week and its intramembranous
When and where does the secondary ossification center appear?
around 17 y/o at the sternal end and its endochondral
what is the last bone to ossify?
the clavicle around 25 y/o
What is the most commonly broken bone?
the clavicle
what part of the clavicle is usually broken?
the first lateral 3rd
A hereditary condition in which ossification fails or is defective of the clavicle
cleidocranial dysostosis
Where does the clinical arm start and end?
starts at the acromion process and ends at the distal part of the humerus
An undescended scapula brought about by attachment to cervical vertebrae by either bone, cartilage, or fibrous attachment
Sprengel’sdeformity
Failure of acromion to fuse with the rest of the bone
Os Acromidae
Primary functions of female mammary glands
provide nourishment and immune benefits
Describe estrogens affect on lactation
after being secreted by the ovaries and placenta it promotes growth of the duct system of glands
Describe progesterones affect on lactation
after being secreted by the placenta and ovaries promotes growth of secretory cells
Describe prolactins affect on lactation
after being secreted by the anterior pituitary it promotes production of milk after birth
Describe oxytocins affect on lactation
after being secreted by the posterior pituitary it promotes the release of milk
A creamy white yellowish fluid that is secreted during the first week of pregnancy
colostrum
What benefits does colostrum provide?
its rich in immunoglobulins and lactoferrin as well as growth factors to help with the infants GI tract
Describe transitional milk
from about day 6-15 its produced and is higher in lactose and fat than colostrum with lower immunoglobulin
Describe Mature Milk
present from day 15 to weaning and is 88%water, 7% lactose, 4% fat, and 1% protein
Inverted nipples
may be a carcinoma pulling in underlying lactiferous ducts
Supernumerary nipples
extra nipples
What type of tumor is breast cancer most common?
adenocarcinoma
Describe chronic cystic mastitis
benign cysts
Secretions from the breasts that are not associated with pregnancy or lactation
galactorrhea
Origin of Pectoralis Major
Clavicle, sternum and upper ribs, and external oblique muscle
Insertion of Pectoralis major
lateral aspect of intertubercular groove
Actions of Pectoralis Major
Adduction and medial rotation of the humerus
Forced inspiration when rib cage is raised and humerus stabilized
Nerve supply to Pectoralis Major
medial (C8-T1) and lateral (C5-C7) pectoral nerves
Origin of Pectroalis Minorr
Upper ribs
Insertion of Pectoralis Minor
coracoid proccess
Actions of Pectoralis Minor
Involved with protraction/retraction
Forced expiration
Nerve Supply of Pectoralis Minor
Medial Pectoral (C8-T1)
Describe Poland Syndrome
Unilateral condition in which both the pectoralis minor and major are missing accompanied by atrophy by mammary glands, missing ribs, and hand of affected side shows webbing
Origin of Subclavius
first rib
Insertion of Subclavius
subcclavian grooce
Actions of Subclavius
Pulls clavicle medialy and stabilizes SC joint
serves as cushion between fractured clavicle and ruptured blood vessels
Nerve supply to Subclavius
nerve to the subclavius (C5-C6)
The anterior wall of the axilla is formed by
the pectoralis major
the posterior wall is formed by
the latissimus dorsi and teres major
the medial wall is formed by
the serratus anterior and upper ribs
the lateral wall is formed by
the proximal medial aspect of the arm
The upper trunk of the brachial plexus is formed from
C5 and C6
The middle trunk of the brachial plexus is formed from
C7
The lower trunk of the brachialplexus is formed from
C8 and T1
The lateral cord of the brachial plexus is formed from
the anterior division ofthe upper and middle trunks and fibers from C5-C7
The medial cord of the brachial plexus is formed from
the anterior division of the lower trunk and fibers from C8-T1
The posterior cord of the brachial plexus is formed from
the posterior division of all three cords and fibers from C5-T1
Two nerves directly from spinal nerves
the dorsal scapular and long thoracic
Nerves from upper trunk
suprascapular and subclavius
Nevres from the lateral cord
lateral pectoral, musculocutaneous, and part of median
Nerves from medial cord
medial pectoral, medial brachial cutaneous, medial antebrachial cutaneous, ulnar, and part of median
Nerves from the posterior cord
upper subscapular, lower subscapular, thoracodorsal, axillary, and radial
The segmental innervation of Dorsal scapular nerve
C5
The motor supply of dorsal scapular nerve
rhomboid major and minor, and levator scapula
The articular supply of the dorsal scapular nerve
acromioclavicular nerve
The segmental innervation of long thoracic nerve is
C5-C7
The motor supply of long thoracic nerve is
serratus anterior
The segmental innervation of the suprascapular nerve is
C5-C6
the motor supply of the suprascapular nerve is
the supraspinatus and infraspinatus
the articular supply of the suprascapular nerve is
the shoulder joint
The segmental innervation of the subclavius is
C5-C6
The motor supply of the subclavius is
the subclavius and diaphragm
The articular supply of the subclavius is
the sternoclavicular joint
The segmental innervation of the lateral pectoral nerve is
C5-C7
the motor supply of the lateral pectoral nerve is
the pectoralis major
The musculocutaneous nerve continues into the forearm as the
lateral antebrachial cutaneous nerve
the segmental innervation of the musculocutaneous nerve is
C5-C7
the motor supply of the musculocutaneous is
the coraobrachialis, biceps brachii, and brachialis
the articular supply of the musculotaneous nerve is
the elbow joint
the cutaneous supply of the musculocutaneous nerve is
the lateral aspect of the forearm
the segmental innervation of medial pectoral nerve is
C8-T1
the motor supply of medial pectoral nerve is
the pectoralis major and minor
the segmental innervation of the medial brachial cutaneous is
T1
the cutaneous supply of medial brachial cutaneous nerve is
the medial aspect of the arm
the segmental innervation of the medial antebrachial cutaneous nerve is
C8-T1
the cutaneous supply of the medial antebrachial cutaneous nerve is the
medial aspect of the forearm
Segemental innervation of Ulnar nerve
C8-T1
Motor supply of the Ulnar nerve
flexor carpi ulnaris and half flexor digitorum profundus, and hypothenar muscles
Articular supply of the Ulnar nerve
elbow and wrist joints
Cutaneous supply of the Ulnar nerve
1/4 medial aspect of the palm and dorsum of the hand; skin of digit 5 and part D4
What nerve is formed from more than one cord of the brachial plexus?
the median nerve (lateral and medial cord)
Segmental innerveation of the Median nerve
C6-T1
Motor supply of the Median Nerve
prontor teres, flexor carpi radialis, palmaris longus, flexor digitorum superficialis, flexor pollicus longus, pronator quadratus, and halfof the flexor digitrum profundus, and thenar muscles
Articular supply of the Median nerve
elbow and wrist joint
Cutaneous supply of the Median nerve
lateral 3/4 of palmar surface and skin of first 3 1/2 digits
Segmental innervation of upper subscapular nerve
C5
motor supply of the upper subscapular nerve
subscapularis
Segmental innervation of the lower subscapular nerve
C6
motor supply of the lower supscapular nerve
subscapularis and motor supply
Segemtnal innervationof thoracodorsal nerve
C6-C8
motor supply of thoracodorsal nerve
latissumus dorsi
Segmental innervation of axiallary nerve
C5-C6
motor supply of axiallary nerve
deltoid and teres minor
articular supply of axillary nerve
shoulder joint
cutaneous supply of axillary nerve
lateral aspect of arm
Segmental innervation of radial nerve
C5-T1
motor supply of radial nerve
triceps brachii and aconeus; allposterior forearm muscles
articular supply of radial nerve
elbow and wrist joints
cutaneous supply of radial nerve
posterior arm and forearm; dorsum of hand and small area below thumb on palmar sider
What is a prefixed brachial plexus?
instead of C5 being first and T1 last, C4 is first and C8 last
What is a postfixed brachial plexus?
instead of C5 being first and T1 last, C6 is first and T2 last.
Define pararlysis
complete loss of muscular movement
Define Paresis
movement can be performed but is weak
Define anesthesia
partial or complete loss of sensation w/ or w/o loss of consciousness
Define paresthesia
loss of cutaneous sensation
Describe Erb-duchenne palsy
comes from a traction injury that damages C5/C6 and one will have impaired shoulder movement along with loss of sensation in C5/C6 deratomes
What could cause Erb-duchennes?
Difficult birth that stretches infants neck, falling blow to shoulder, or heavyweight hitting shoulder
Describe Klumpke’s Palsy
comes from a traction injury to C8/T1 in which one will have issues moving hand and digits and a loss of sensation along C8/T1 deratomes
What could cause Klumpke’s Palsy
an individual falling and catching themselves or forced pulling on should of infant during birth; forceful abduction of humerus
What is a longer than normal cervical transverse process called?
Cervical rib
What issues could a cervical rib pose?
interferencer with bracial plexus
Describe Thoracic Outlet Syndrome (TOS)
a compression of the cords of the brachial plexus and axillary artery
List some synptoms of TOS
pain, paresthesia, decreased skin temp, and fatigue of limb
What is the first branch of the axillary artery?
the superior thoracic which emerges just as the axillary artery comes out from under the clavicle
What muscles does the superior thoracic supply?
Pectoralis major and minor, subclavius, and wall of thorax
Which branch of the axillary artery curls around the upper border of the pec. major?
the thoracoacromial
List the branches of thoracoacromial
acromial, pectoral, clavicular, and deltoid
Which branch of the axillary artery is along the lateral border of the pec. major?
the lateral thoracic
Whart muscles does the lateral thoracic artery supply?
serratus anterior, both pecs, mammary glands, and intercostal muscles
What is the largest branch of the axillary artery?
the subscapular
List the two branches of the subscapular artery
thoracodorsal and circumflex scapular
What muscles does the thoracodorsal supply?
latissumus dorsi and subscapularis
What muscles does the circumflex scapular artery supply?
supraspinatus, infraspinatus, teres major and minor, triceps brachii, and part of deltoid
Which branch of the axiallary artery forms a circle around the surgical neck of the humerus?
the anterior and posterior humeral circumflex arteries
What structures do the humeral circumflex arteries supply?
deltoid, shoulder joint, teres muscles. and proximal part of humerus
