Shared Flashcard Set

Details

ML 125 Physiology/Pathology Exam 2 Ch 7 & Slides
Textbook pages 160-168 (per syllabus) & Unit 2 PP slides
108
Physiology
Undergraduate 2
02/13/2014

Additional Physiology Flashcards

 


 

Cards

Term
epimysium
Definition
connective tissue, continuous with the tendon, surrounding a typical muscle
Term
perimysium
Definition
the membrane surrounding fascicles (bundles of muscle fibers)
Term
endomysium
Definition
connective tissue sheath encasing each muscle fiber
Term
myofibrils
Definition
cylinders filling the endomysium (each myofibril is made up of several sarcomeres)
Term
sarcomeres
Definition
protein threads arranged in contractile units which comprise myofibrils
Term
myofilaments
Definition
protein threads, called "thick" and "thin", comprising each sarcomere
Term
myosin
Definition
the protein that comprises "thick" myofilaments
Term
actin
Definition
the protein that comprises "thin" myofilaments
Term
Z lines
Definition
dark bands separating repeating units of actin and myosin filaments - these give muscle the striated appearance
Term

ATP

(adenosine triphosphate)

Definition
needed for contraction and relaxation - provides the energy to help the myosin heads form and break the crossbridges with actin
Term
calcium (Ca++)
Definition
needed for contraction and relaxation - stored away in the sarcoplasmic reticulum (SR) when the muscle is relaxed - when the muscle is stimulated, Ca is released from the SR and allows actin, myosin, and ATP to interact, which causes the contraction
Term
sodium ion channels
Definition
found on the muscle fiber membrane - open when acetylcholine (ACh) is released by the nervous system
Term
sarcolemma
Definition
the cell membrane of each muscle fiber
Term
Duchenne's muscular dystrophy (DMD)
Definition
a genetic, incurable myopathy - the most common form of muscular dystrophy and found overwhelmingly in boys - caused by a mistake in the gene for a protein called dystrophin - without functional dystrophin, muscle fibers degenerate - all types of muscle (smooth, cardiac and skeletal) are affected
Term
Myasthenia gravis (MG)
Definition
literally means "grave muscle weakness" - is an autoimmune disorder in which the immune system attacks and destroys a large number of ACh receptors at the neuromuscular junction - is a rare disorder most common in women under 40 and men over 50
Term
Tetanus
Definition
aka "lockjaw" - is a muscle disorder cause by an untreated bacterial infection of a wound - the bactria, found in soil, keeps muscle constantly contracted
Term
Acetylcholine (ACh)
Definition
a neurostransmitter - opens the sodium ion channels and sets the process of muscle contraction into motion
Term
Acetylcholinesterase (AChE)
Definition
the enzyme responsible for cleaning up the nerve synapse
Term
Glycogen
Definition
a carbohydrate stored in the muscle
Term
Glucose
Definition
converted from glycogen by the muscle when needed
Term
Fermentation
Definition
anaerobic - used by the body to break down glucose and provide ATP for very intense exercise
Term
Lactic acid
Definition
a byproduct of fermentation, which builds up in muscles causing temporary muscle fatigue, or weakness
Term
Oxygen debt
Definition
the additional oxygen needed to convert lactic acid back to glucose - the body overcomes this debt by increasing the rate of breathing and heart rate until it has returned to normal
Term
Visceral muscle
Definition
aka smooth muscle - found in large organs except the heart - the ability of smooth muscle to expand and contract plays a vital role in many of the body's internal workings
Term
Vasodialate
Definition
blood vessels get larger in diameter
Term
Vasoconstrict
Definition
blood vessels get smaller in diameter
Term
Sphincter
Definition
special type of smooth muscle, found throughout the digestive sytem - usually occur between major digestive organs - donut-shaped muscles that act as doorways to let materials in and out by alternately contracting and relaxing
Term
Cardiac muscle
Definition
Squeezes blood out of the chambers of the heart, causing blood to circulate throughout the body - involuntary muscle
Term
Intercalated discs
Definition
connect cardiac muscle fibers to each other
Term
Strains (tears)
Definition
caused by acute injury - varies with severity, may include pain, stiffness, bruising, weakness, loss of function
Term
Tendinosis/Tendinitis
Definition
caused by chronic overuse or disease - varies with severity, may include pain, stiffness, weakness
Term
Shin splints
Definition
caused by repetitive lower body exercise such as running; can be due to faulty foot mechanics or footwear - pain in the tibia region
Term
Cramps/spasms
Definition
caused by sudden, severe involuntary muscle contraction - can be result of prolonged physical activity, excessive fluid/electrolyte loss, menstruation
Term
Fibromyalgia syndrome
Definition
cause unknown, but may be neurological - chronic pain, bilateral tenderness, fatigue, sleep disorders, depression, exercise intolerance
Term
Mitochondrial myopathy
Definition
caused by defect in ATP production in mitochondria - progressive muscle weakness, often accompanied by hearing loss, diabetes mellitus, heart problems, nervous system disorderds, and other biochemical abnormalities
Term
skeletal muscle
Definition

voluntary

striated

many nuclei

moves or positions the skeleton

Term
cardiac muscle
Definition

heart

involuntary

striations; interconnecting fibers

intercalated discs

circulates blood; maintains BP

Term
fibrillation
Definition
the process of beating
Term
myogram
Definition
measures contractibility
Term
smooth muscle
Definition

involuntary

no striations

aka visceral smooth muscle

multiunit smooth muscle

intermediate filaments

longer contractions than skeletal muscle

long term tone/can stretch w/o tension

Term
skeletal muscles are responsible for
Definition
posture, joint stability, heat production (through movement)
Term
characteristics of muscle: excitability
Definition
receive and respond to stimuli
Term
characteristics of muscle: contractibility
Definition
ability to shorten or contract
Term
characteristics of muscle: extensibility
Definition
can be stretched or extended
Term
characteristics of muscle: elasticity
Definition
recoil or return to original shape and length
Term
a whole skeletal muscle is considered an
Definition
organ
Term
each muscle consists of:
Definition

skeletal muscle tissue

connective tissue

nerve tissue

vascular tissue

Term
epimysium
Definition
connective tissue wrapped around hundreds (thousands) of bundled muscle fibers
Term
facia
Definition
bundles are separated from each other with another c.t. wrap
Term
fasciculus
Definition
compartments containing a bundle of muscle fibers
Term
perimysium
Definition
a layer of c.t. surrounding the fasciculus
Term
endomysium
Definition
c.t. which surrounds each muscle fiber within the fasciculus
Term
muscle fiber
Definition
a single, cylindrical muscle cell
Term
sarcolemma
Definition

membrane of muscle fiber

contains cholinesterase

Term
neuromuscular junction
Definition
motor neuron ending on muscle fiber (N.S. stimuli)
Term
sarcoplasma
Definition
cell cytoplasm; contains many nuclei and mitochondria
Term
sarcoplasmic reticulum
Definition
endoplasmic reticulum of muscle cells; stores Ca++ for contraction
Term
transverse tubules (T tubules)
Definition
inward extensions of the sarcolemma
Term
myofibrils
Definition
cylinders of thick and thin myofilaments
Term
sarcomeres
Definition
compartments of myofilaments
Term
myofilaments
Definition

contracting proteins

myosin (center)

actin (ends)

Term
myosin
Definition

thick myofilaments

A-band (anisotropic - dark)

single protein molecule with tail

has actin and ATP binding sites

Term
actin
Definition

thin myofilaments

I-band (isotropic - light)

has myosin binding site

forms cross-bridges with Ca++

contains proteins: troponin and tropomyosin

Term
actin & myosin + Ca++ =
Definition
contraction
Term
sarcomeres
Definition
are contractile units - protein
Term
myosin
Definition
center
Term
actin
Definition
ends
Term
functional unit of myofibril
Definition
extends from one Z line to another
Term
Z lines
Definition
separate each sarcomere
Term
striations are due to
Definition
alternating A & I bands
Term
H band
Definition
central zone of myosin where there is no overlapping, only myosin filaments
Term
Z and M lines
Definition
points of myofilament connections
Term
mitochondria
Definition
many, due to energy needs
Term
neuromuscular junction
Definition
an impulse via nerve cell will stimulate a muscle
Term
sources of energy: ATP
Definition

no large stores

supply of ATP is only enough for 4-6 seconds

myosin filaments contain ATPase

Term
sources of energy: creatine phosphate
Definition
broken down to phospate and energy
Term
sources of energy: glucose
Definition

from stored glycogen ---> energy

glycogen from muscle and fat stores

Term
Contraction: Sliding Filament Theory
Definition

requires energy

sarcolemma is polarized - outside increased +++

nerve impulse (neuromuscular junction):

release of acetylcholine (ACh)

changes sarcolemma permeability

Action Potential occurs

depolarization of sarcolemma

sarcoplasmic reticulum releases Ca++

Ca++ binds troponin-tropomyosin complex (found in actin)

myosin splits ATP

cross bridges: myosin ---> actin

all sarcomeres shorten ---> contraction

sarcolemma repolarizes

sarcolemma ---> acetylcholinesterase (AChE): inactivates ACh

Term
sarcolemma repolarizes (steps)
Definition

Ca++ ---> sarcoplasmic reticulum

cross bridges unbind

Na+ out ---> K+ in

cell membrane repolarized

muscle cell relaxes

Term
Contraction: Muscle Cell Respiration: Aerobic
Definition

uses oxygen (oxidation of glucose)

glucose ---> pyruvic acid + energy

glycogen + oxygen ---> glucose + ATP + heat

pyruvic acid + oxygen ---> CO2 + HOH + ATP

**myoglobin: stores oxygen from rbc hgb - first source of oxygen from blood hgb

 

Term
Contraction: Muscle Cell Respiration: Anaerobic
Definition

no oxygen required

glucose ---> lactic acid

increased lactic acid ---> decreased contractibility

increased lactic acid ---> PAIN

pain will stop when respirations replace "O2 Debt"

Term
Oxygen Debt
Definition

caused by strenuous exercise

pyruvic acid ---> lactic acid in absence of oxygen

increased lactic acid ---> decreased pH ---> acidosis

calcium pump not efficient - Ca++ not moved back into sarcoplasmic reticulum

muscle fatigue ---> incomplete contractions

muscle cramps will occur

lactic acid enters blood ---> liver

lactic acid ---> glucose (uses ATP and oxygen)

homeostasis achieved by increased breathing

lactic acid ---> CO2 + HOH

Term
Myotonia
Definition

pathology

increase in muscle excitability and contractibility

Term
Botulism (Clostridium botulinum)
Definition
caused by toxin released by bacteria - ACh is not released, muscles cannot contract, results in respiratory failure - treated with anti-toxin
Term
Contracture (Volkmann's)
Definition
permanent shortening of a muscle because it has been replaced with connective tissue
Term
muscle spasms
Definition
affect a single muscle in a large group
Term
muscle cramps
Definition
painful spasmodic contraction that won't release
Term
muscle tics
Definition
spasmodic twitching made involuntary by muscles usually under voluntary control
Term
muscle tremor
Definition
rhythmic, involuntary and purposeless
Term
fasciculation
Definition
involuntary, brief twitch of an entire motor unit under the skin - seen in MS and amyotrophic lateral sclerosis (ALS or Lou Gherig's)
Term
fibrillation
Definition
spontaneous contraction of a single muscle fiber NOT visible under the skin
Term
hypertonia
Definition
increased muscle tone
Term
hypotonia
Definition
decreased muscle tone (flaccid)
Term
muscle strain
Definition

muscle tear

(not same as muscle pull)

Term
myalgia
Definition
muscle pain
Term
myoma
Definition
benign tumor of muscle
Term
myomalacia
Definition
pathological softening
Term
myositis
Definition
inflammation of muscle fibers
Term
muscle trauma
Definition

hernia

bruise

strain/sprain (ligament or tendon)

bursitis/tendonitis

arthritis: osteo or rheumatoid (joint)

Term
Carpal Tunnel Syndrome
Definition
a median entrapment neuropathy that causes paresthesia, pain, numbness, and other symptoms in the distribution of the median nerve due to its compression at the wrist in the carpal tunnel
Term
muscle infection
Definition

Group A strep - flesh eating bacteria

causes myitis

Term
hypercalcemia
Definition

increased Ca++

sustained contractions

can affect heart

Term
hypocalcemia
Definition

decreased Ca++

weakened contractions

Term
Treppe
Definition
gradual increase in contraction
Term
Isotonic exercises
Definition
constant tension and movement (constant muscle contraction)
Term
Isometric exercises
Definition
tension with no movement (limited muscle contraction)
Term
Anti-AChE Agents
Definition

helps with prolonged contractions

Curare - plant derivative - poison - causes paralysis by binding and blocking ACh receptors (no depolarization)

Term
Muscle Death
Definition

ATP breaks down

Actin and Myosin cannot detach

Myofilaments remain locked - contraction

Body remains rigid (rigor mortis - stiff - 15-25 hours)

Muscle proteins break down, stiffness disappears

Supporting users have an ad free experience!