Quiz 1 Flashcards
What is the term used to refer to the cytoplasm of a muscle fiber?
sarcoplasm
Are the amounts of sarcoplasm in each muscle fiber the same?
no, they will vary from fiber to fiber
What is the difference between dark and light muscle fibers?
the amount of sarcoplasm within the majority of the fibers
Are type I fibers dark?
yes
Are type II fibers dark?
no
Are type I fibers light?
no
Are type II fibers light?
yes
What type of muscle fibers are found in muscles where long, sustained or continuous contraction are required (i.e. posture maintenance, ocular, respiratory, and masticatory muscles)?
Type I
What type of muscle fibers are associated with endurance activities?
Type I
What type of muscle fibers are associated with relatively higher levels of continuous metabolic activity (aerobic metabolism)?
Type I
What type of muscle fibers are used for quick, more powerful activities and thus related to speed and strength (i.e. sprinting, weight lifting, etc.)?
Type II
What type of muscle fibers are associated with anaerobic metabolism?
Type II
What type of muscle fibers have large amounts of sarcoplasm and myoglobin?
Type I
What type of muscle fibers have lesser amounts of sarcoplasm and myoglobin?
Type II
What type of muscle fibers have extensive capillary beds?
Type I
What type of muscle fibers have fewer capillary beds?
Type II
What type of muscle fibers are slow twitch?
Type I
What type of muscle fibers are fast twitch?
Type II
Which type of muscle fibers are fatigue resistant?
Type I
Which type of muscle fibers fatigue easily?
Type II
What type of muscle fibers have numerous mitochondria?
Type I
What type of muscle fibers have more fatty acids and less glycogen?
Type I
What type of muscle fibers have more glycogen and less fatty acids?
Type II
What type of muscle fibers atrophy with immobilization?
Type I
What type of muscle fibers atrophy with age?
Type II
What type of muscle fibers exhibit characteristics which are somewhere between type I and type II fibers?
Intermediate
Intermediate fibers contract faster than type __ but slower than type __.
I;II
What type of muscle fibers do intermediate fibers histologically resemble?
Type II
What is the muscle fiber’s cell membrane?
Sarcolemma
What is an elaborate, tubular network which functions to store and transport calcium ions to the myofibrils?
sarcoplasmic reticulum
What is a tubular invagination of the sarcolemma that allows electrical (nerve) impulses to enter the muscle fiber and make their way to the myofibrils?
Transverse Tubules
What do the transverse tubules (T-System) allow for the release of?
calcium in the sarcoplasmic reticulum
What is a red protein pigment found in the sarcoplasm of a muscle fiber?
Myoglobin
What protein gives color to muscle?
Myoglobin
What protein stores oxygen for metabolism in muscle fibers?
Myoglobin
What is the contractile apparatus of the muscle fibers?
Myofibril
Does snake venom cause an action potential?
No
What do snake venom’s neurotoxins prevent?
prevent ACH from binding to ACH receptor sites
What are the two type of toxins that snake venom contain?
cytotoxins and neurotoxins
What is the difference between nicotine and ACH’s action potentials?
nicotine’s are much more prolonged (because it is not broken down by ACHe)
What is an example of a drug that is able to compete with ACH molecules in binding to the ACH receptor sites?
nicotine
What is the condition where a pregnant women suffering from Myasthenia Gravis has about a 25% chance of having her infant born with the condition?
transitional neonatal myasthenia gravis
What is a common condition associated with Myasthenia Gravis?
Hyperplasia of the thymus gland
What are the first muscles affected by Myasthenia Gravis?
muscles supplied by the cranial nerves (muscles of the eyes and face) and in many cases will progress to muscles of the extremities
With an autoimmune disorder like Myasthenia Gravis, the body’s immune system produces abnormal __________, which damage and destroy the ___ ________ sites on the __________ of the muscle fibers.
antibodies; ACH receptor; sarcolemma
What is the most common neuromuscular junction disorder?
myasthenia gravis
What does ACHe break down ACH into?
acetate and choline
What is the enzyme that breaks down ACH?
acetycholinesterase (ACHe)
What does ACH binding to sarcolemma result in?
What does ACH binding to sarcolemma result in? setting off an action potential down the transverse tubules, which leads to an interaction between actin and myosin (muscle contraction)
ACH will _______ across the ________ _____, where it will bind to very specific receptor sites on the __________ of the muscle fiber.
diffuse; synaptic cleft; sarcolemma
What are the three portions of the neuromuscular junction?
presynaptic portion, postsynaptic portion, and synaptic cleft
Where is the terminal end of the motor unit?
sarcolemma of the muscle fiber
Where does the motor unit originate?
ventral (anterior) horn of the grey matter of the spinal cord or brain stem (CNS)
How many motor fibers do muscles that carry out non-precision type of activities (i.e. locomotion) have?
thousands
Muscles that carry out precision type of activities (i.e. placing finger tips together, movement of the eyes) contain a motor unit with _____ number of fibers
fewer
What does the strength of a muscle contraction depend on?
the number of motor units being activated or recruited at the same time
What is the smallest part of the muscle which can contract independently?
motor unit
What does a motor unit consist of?
a single motor neuron (nerve fiber) and the group of muscle fibers it supplies
_______ muscle fibers will contract at the same moment, all being supplied by branches of ___ spinal _____ nerve fiber.
several; one; motor
What will never happen when a muscle is functioning normally?
individual muscle fiber will never contract independently
Motor nerves transmit ________/_____ impulses from the ___ to each individual ______ _____, the result of which is a motor response (___________).
efferent; motor; CNS; muscle fiber; contraction
How do nerve fibers enter and leave a muscle?
connective tissue components of the muscle
What is the nerve supply of skeletal muscle?
motor nerve fiber and sensory nerve fiber
What is the chemical composition of muscle?
75% H2O, 20% protein (most abundant is myosin), and 5% others
What are the legitimate reasons that a physician would prescribe the use of anabolic steroids?
restore hormonal levels in males with low testosterone levels, improve mood and alleviate depression, and patients who are chronically ill and become debilitated by a lack of appetite (the drug enhances appetite and increases body weight and muscle mass)
How do anabolic steroids physiologically work?
increases secretions of growth hormone which activates protein synthesis and prevents protein breakdown
What happens when adolescents take anabolic steroids?
premature closing of the growth plates, which leads to shortened stature among other problems
What are the short term side effects for females using anabolic steroids?
increase in the side of the clitoris, decrease in the size of the mammary glands, development of facial hair, deepening of the voice, and tendon damage
What are the long term side effects of anabolic steroids?
problems with the cardiovascular system, digestive system (especially the liver), reproductive system (enlarged prostate), and endocrine system
What are the short term side effects of anabolic steroids?
headaches, dizziness, and nausea; acne, especially on the back; shrinkage of the testicles; increased aggressiveness; gynecomastia, dveleopment of breast tissue (may be due to the fact that the drug is converted by liver enzymes into a type of estrogen); tendon damage (since tendons respond very slowly to strength regimes and anabolic steroids have little or no effect on increasing the size of tendons or even inhibit the formation of collagen)
How long are typical anabolic steroid cycles?
6 to 8 weeks
What is a procedure where the user starts with a low dosage, raises to a peak, and then begins to taper down the amount being taken?
pyramiding
What is the term used when the user takes both oil and water based anabolic steroids?
stacking
What kind of anabolic steroid is usually taken in pill form, but has more side effects and cleared from the system within 3 to 4 weeks?
water based
What kind of anabolic steroid is usually injected, but has fewer side effects and a longer lasting detectability?
oil based
In its natural form, testosterone is rapidly metabolized and cleared from the liver, but the synthetic forms have been designed to what?
prevent metabolic degradation, thus prolonging or enhancing its effect on the tissue
The designer anabolic steroid would have minimal __________ effect and more ________ effect.
androgenic; anabolic
What refers to the development of secondary sexual characteristics?
androgenic
What refers to the stimulation of protein synthesis and thus induction of growth?
anabolic
Anabolic steroids were developed to try to separate the _______ effect of the hormone from its _________ effect.
anabolic; androgenic
What hormone are anabolic steroids the synthetic form of?
testosterone
What is the risk of using EPO with a normal RBC count?
blood can thicken to dangerously high levels and lead to possible cardiac problems and death
Why was synthetic EPO originally produced?
patients with certain types of anemia
Where does EPO travel to and why?
bone marrow to produce RBCs
Where is EPO naturally found?
kidneys
What are the risks associated with blood doping?
rashes and fevers, acute hemolysis, transmission of viruses, fluid overload which can lead to kidney damage and intravascular clotting of blood
How does blood doping help an athlete?
increases the oxygen carrying capacity of RBCs; the thoery is that if you increase the concentration of RBCs you can increase your endurance
How can caffeine help an athlete?
may help burn fatty acids more efficiently (they are released more easily into the blood) and may increase calcium permeability; this effect should also delay the utilization of glycogen (phase three) and could give an advantage during endurance competitions
What are side effects associated with carbohydrate loading?
feeling light headed, dizzy and lethargic (may be due to hormonal imbalances and increased blood pressure); mental acuity may suffer and judgment may be impaired (thought to be due to hypoglycemia); for every gram of glycogen that is stored in the muscle, there is an approximate increase of 3 grams of water (this may lead to several extra pounds of weight)
Studies have shown that carbohydrate loading will produce localized increased synthesis of ________ in the depleted muscle groups; however, this increase in muscle ________ levels will not increase a muscle’s ________ nor allow one to run ______.
glycogen; glycogen; strength; faster
What dietary manipulation is used to increase the store of glycogen in muscle fibers?
glycogen/carb loading
What occurs during phase three or exercise?
muscle fibers go back to anaerobic production of ATP and utilize the remaining stored glycogen, which results in an accumulation of lactic acid within the fibers
Which phase of exercise occurs as exercise intensifies?
phase 3
What occurs during phase two of exercise?
shift in metabolism to the more efficient aerobic metabolism and the use of fatty acids to produce ATP
What percentage of stored glycogen is utilized during phase one of exercise?
up to 20%
During phase one of exercise what are the primary fuel sources?
creatine phosphate and glycogen
What bogs down anaerobic metabolism?
lactic acid
What metabolic pathway is quicker, aerobic or anaerobic?
anaerobic
Where is glycogen stored?
muscle fibers/ liver cells
What is the process which produces ATP using glycogen called and is it aerobic or anaerobic?
glycolysis/anaerobic
How are fatty acids stored in the body’s fat cells?
triglycerides
What pathway prefers fatty acids to produce ATP?
aerobic pathway
What pathway creates excess energy released as heat and contributes to keeping the body at its most efficient temperature?
aerobic pathway
Where does the aerobic pathway take place?
mitochondria
In regards to ATP, what is the movement of a muscle a result of?
continuous breakdown and reconstruction of ATP
How does the addition of ATP allow the system to operate?
by allowing myosin to interact with actin
What occurs to the rest of the regulatory proteins when calcium binds to troponin?
tropomyosin changes shape (moving it aside) and exposes the myosin binding site on the actin molecule
What molecule eliminates the inhibition caused by the regulatory proteins and thus allows muscle contractions to occur?
calcium
The nerve impulse from the _________ _______ stimulates the release of calcium from the ____________ _________.
transverse tubules; sarcoplasmic reticulum
What are the two contractile proteins and where are they found?
actin, found mainly in the I-bands and myosin, found mainly in the A-bands
What type of proteins are the main proteins of skeletal muscle?
contractile proteins
What are anatomical boundaries of one sarcomere?
Z line to Z line
What is the light area in a myofibril?
I-band
What is the dark area in a myofibril?
A-band
What are the light areas in the middle of each dark band?
H-band
What is the thin dark line down the center of each H-band?
M-band
What is the name of the bacteria that causes botulism?
clostridium botulinum
How does clostridium botulinum affect ACH?
blocks the release of ACH from the presynaptic portion of the neuromuscular junction
What muscles are first affected by botulism?
muscles supplied by the cranial nerves; can progress to affect limb and respiratory muscles
Where are organophosphates found?
insecticides
What toxin inactivates ACHe?
Organophosphates
How do organophosphates affect ACH?
ACH can no longer be degraded, resulting in ACH accumulation at the postsynaptic portion of the junction
