Exam 1 Flashcards
Myology
The branch of anatomy that deals with skeletal muscular system
Contractility
Specific function of skeletal muscle is the the production of voluntary movement.
Functions of Skeletal Muscle
- ) Movement
- ) Stability
- ) Communication
- ) Control of body openings and passages
- ) Heat production
Musculoskeletal system
Composed of bones and joints of which body movements occur
Muscle fiber
Basic structural unit of a muscle
Fasiculi
Muscle fibers are grouped into bundles
Connective tissue
Muscle fibers and fasciculi are bound together by _________
Connective investment of muscle
Function:
- ) connect muscle to bone or other structure
- ) provides a route through which nerves and blood vessels reach the muscle fibers.
- ) provide a non-contractile framework which allows the contraction of a muscle fiber to be transmitted to bone
Endomysium
The delicate connective tissue sheath which surrounds each individual muscle fiber and connects it to adjacent muscle fibers
Perimysium
A more dense layer which surrounds each fasciculi and divides the muscle into a series of separate compartments.
Epimysium
The dense layer of connective tissue which surrounds the entire muscle and separates the muscle for the surrounding tissue, organs, and other muscles. The ______ is continuous with deep fascia in the area and will continue as the tendon of the muscle.
Myofibrils
The contractile units of the muscle and each fiber contains dozens to hundreds of these
Sarcolemma
Tough specialized membrane that each fibers are contained in.
Hypertrophy
The type of increase in the size of a muscle, which is due to an increase in the size of each individual muscle fiber.
Hyperplasia
An increase in the size of a muscle due to an actual increase in the number of muscle fibers. This method involves subjecting the muscle fibers to high resistance exercise which induce injury to the individual fibers, which is then followed by a regenerative process.
Sarcoplasm
Used to refer the cytoplasm of a muscle fiber. Muscles being classified as either red(dark) or white(light) is based on the amount of ________ within the majority of fibers found in the respective muscle.
Type 1 fibers (Dark)
- ) Aerobic (large amounts of sarcoplasm and myoglobin)
- ) extensive capillary beds
- ) slow twitch
- ) fatigue resistant
- ) numerous mitochondria
- ) more fatty acids/ less glycogen
- ) ATROPHY WITH IMMOBILIZATION
Type II fibers (light)
- ) Anaerobic (lesser amounts of sarcoplasm and myoglobin)
- ) fewer capillary beds
- ) fast twitch
- ) fatigue easier
- ) less mitochondria
- ) more glycogen/ less fatty acids
- ) ATROPHY WITH AGING
Intermediate fibers
> Exhibit characteristics which are somewhere between type 1 and type 2 fibers
> contract faster than type 1 but slower than type 2
> have a greater resistance to fatigue but histologically resemble type 2 fibers.
Sarcoplasm Reticulum
An elaborate, tubular network which functions to store and transport calcium ions to the myofibrils.
Transverse Tubules (T-System)
Tubular invaginations of the sarcolemma which allow electrical impulses to enter the muscle fiber and make their way to the myofibrils.
Myoglobin
A red protein pigment which is found in the sarcoplasm of the fiber. Also stores the oxygen needed for the fibers to utilize for metabolism.
Myofilaments
Longitudinally oriented bundles of thick and thin filaments
Sacromere
Myofibrils are composed of numerous of units that are the smallest functional unit of the muscle and anatomically runs from one z-line to the next z-line.
Contractile proteins
Actin: found mainly in I-bands
Myosin: found mainly in the A-bands
Regulatory Proteins
Act to inhibit the interaction of actin and myosin and thus prevent indiscriminate movement
Troponin (Ca bind directly) and tropomyosin
Calcium
Eliminates the inhibition caused by the regulatory proteins and thus allows muscle contractions to occur.
Nerve impulses from the transverse tubules stimulates the release of calcium from the sarcoplasmic reticulum.
ATP
The “fuel” of the muscle
The addition of _____ allows the system to operate, by allowing myosin to interact of a muscle.
Aerobic Pathway
> Take place in mitochondria
More efficient way to produce ATP; not the speediest
Prefers fatty acids to produce ATP
Fatty acids are stored in the body’s fat cells as triglycerides and released into the blood during exercise.
Anaerobic Pathway
> Depends on 2 substances to produce ATP:
> Creatine Phosphate- allows muscle to contract
> Glycogen- produces ATP by the process known as
glycolysis.
Glycogen is stored in either muscle fibers or liver cells.
Lactic Acid: byproducts of glycogen
Phase one
Will last for the first few minutes and creatine phosphate and glycogen are the primary fuel sources. As much as 20% of the total glycogen that is stored in a muscle may be utilized during this phase. (Anaerobic) “Needs to be quick”
Phase 2
Will see shift in metabolism to the more efficient aerobic metabolism and the use of fatty acids to produce ATP. “Long as possible”
Phase 3
Which occurs as exercise intensifies will see the muscle fibers going back to the anaerobic production of ATP and thus the utilization of the remaining stored glycogen. It is during this phase that lactic acid can accumulate within the fibers.
Carbo Loading
A dietary manipulation used to increase the store of glycogen in muscle fibers. The ability to utilize glycogen maybe more important that the ability to store it, so a well-trained athlete who already stores more glycogen than normal may gain little from the procedure.
Caffeine
> gets from phase 1 to phase 2 quicker
this effect on fatty acids should delay the utilization of glycogen
diuretic
Blood Doping/ Induced Erythrocythemia
This procedure is to increase the oxygen carrying capacity of red blood cells. This can increase their endurance and thus exercise longer. “Effects phase 1 and 3” “Increased blood cells; Increased fatty acids”
Risks associated:
- ) rashes and fevers
- ) acute hemolysis
- ) transmission of viruses
- ) fluid overload, which can lead to kidney damage and intravascular clotting of blood.
Erythropoietin (EPO)
Normally a naturally occurring hormone produced in the kidneys. Synthetic form of the hormone was produced for use of anemic patients.
Anabolic Steroids
Synthetic form of male hormone, testosterone, and was developed to try to separate the anabolic effect of the hormone from its androgenic effect.
Anabolic
The stimulation of protein synthesis and thus induction of growth
Androgenic
The development of secondary sexual characteristics
Oil based
Usually injected and have fewer side effects, but are detectable for several months, if not longer.
Water based
Usually taken in pill form, but have more side effects. However they are cleared from the system within 3-4 weeks.
Stacking
The user takes several forms of the drug (oil and water based)
Pyramiding
Is a procedure where the user starts with a low dosage, than raises to a peak and then begins to taper down he amount being taken.
Anabolic steroids short term side effects
- ) headaches, dizziness, and nausea
- ) acne, especially on the back
- ) shrinkage of the testicles
- ) increased aggressiveness
- ) GYNECOMASTIA
- ) TENDON DAMAGE
Anabolic steroids long term effects
- ) cardiovascular system
- ) digestive system (especially liver)
- ) reproductive system (the prostate)
- ) endocrine system
Anabolic steroids in females-side effects
- ) increase in the size of the clitoris
- ) decrease in the size of the mammary glands
- ) development of facial hair
- ) deepening of the voice
- ) tendon damage
Adolescents who take anabolic steroids
There is a premature of closing of the growth pates which leads to shortened stature as well as other problems.
Legitimate reasons that a physician would prescribe an anabolic steroids
- ) restore hormonal levels in males with low testosterone levels
- ) improve mood and alleviate depression
- ) patients who are chronically ill (ex: cancer) and become debilitated because of lack of appetite
- ) the drugs enhance appetitive and increase body weight and muscle mass
Chemical composition of muscle
> 75% water
20% protein (most abundant in myosin)
5% others
Highest protein is the eyeball it has 35% protein
Efferent/ motor impulses
Motor nerves transmit ________ from the CNS to each individual muscle fiber, the result of which is a motor response (contraction).
Motor unit
The single motor neuron (nerve fiber) and the group of muscles fibers it supplies is known as ______
Also the smallest part of the muscle which can contract independently
Precision type of activities
Contain motor units with fewer number of fibers
Non-precision type of activities
Ex: locomotion
Have motor units which can consists of thousands of motor fibers.
Motor unit anatomy
> The unit originates in a motor neuron in the ventral (anterior) horn of the grey matter of the spinal cord or brain stem (CNS)
> Continues as the spinal nerves and named peripheral nerves (PNS)
> The neuromuscular junction
> The sarcolemma of the muscle fiber (terminal end of the unit)
Neuromuscular Junction
A physiologically, biochemically and clinically complex portion of the motor unit.
> Presynaptic portion (the nerve ending)
Postsynaptic portion (sarcolemma of the muscle fiber)
Synaptic Cleft (space between the pre and post synaptic portions)
Myasthenia Gravis
> The most common neuromuscular junction disorder and an example of an autoimmune disorder
It produces abnormal antibodies which damage and destroy ACH receptors sites on the sarcolemma of the muscle fibers
It starts by affecting muscle supplied by cranial nerves (CN 7) and will progress to the extremities
Muscle weakness tends to get worse with exercise and gets better with rest
Many patients with this condition will suffer from hyperplasia of they thymus gland or a tumor to the gland (thymoma)
Pregnant mom has a 25% chance of having her infant born with the condition
Nicotine
> An example of a drug that is able to compete with ACH molecules in binding to the ACH receptor
It’s actions are much more prolonged than ACH
Snake Venom
> Contains both cytotoxins (destroy tissue/blood vessels) and neurotoxins (prevents binding ACH = no action potential)
Prevents ACH from binding to the ACH receptor sites
Unlike nicotine they do not cause an action potential to occur
Organophosphates
> Examples include parathion and malathion which are found in insecticides and are able to inactive the ACHe
ACH can no longer be rapidly degraded, resulting in an accumulation of ACH at the postsynaptic portion of the junction
Botulin Toxin
> Toxin that is released from the bacteria known as clostridium botulinum, which causes a sever type of food poisoning.
the toxin blocks the release of ACH from the presynaptic portion of the neuromuscular junction
first it affects the muscles by the cranial nerves but can progress to affect limb and respiratory muscles.
Sensory Nerve Fibers
Are involved with coordination, pain, and proprioception