BIO100 Chptr 9 Muscular System Flashcards
calat-
calat-,
something inserted: intercalated disc—membranous band that connects cardiac muscle cells.
erg-
erg-, work: synergist
—muscle that works with a prime mover, producing a movement.
fasc-
fasc-, bundle: fasciculus
—bundle of muscle fibers.
-gram
-gram, something written: myogram
—recording of a muscular contraction.
hyper-
hyper-, over, more: muscular hypertrophy
—enlargement of muscle fibers.
inter-
inter-, between: intercalated disc
—membranous band that connects cardiac muscle cells.
iso-
iso-, equal: isotonic contraction
—contraction during which the tension in a muscle remains unchanged.
laten-
laten-, hidden: latent period
—period between a stimulus and the beginning of a muscle contraction.
-lemm
-lemm [rind or peel] sarcolemma:
the cell membrane of a muscle fiber.
myo-
myo-, muscle: myofibril
—contractile bundle of filaments within a muscle cell.
reticul-
reticul-, a net: sarcoplasmic reticulum
—network of membranous channels within a muscle fiber.
sarco-
sarco-, flesh: sarcoplasm
—substance (cytoplasm) within a muscle fiber.
syn-
syn-, together: synergist
—muscle that works with a prime mover, producing a movement.
tetan-
tetan-, stiff: tetanic contraction
—sustained muscular contraction.
-tonic
-tonic, stretched: isotonic contraction
—contraction during which the tension of a muscle remains unchanged.
-troph
-troph, well fed/(trophy)nourishment: muscular hypertrophy
—enlargement of muscle fibers.
voluntar-
voluntar-, of one’s free will: voluntary muscle
—muscle that can be controlled by conscious effort.
fascia
Layers of connective tissue enclose and separate all parts of a skeletal muscle. An individual skeletal muscle is separated from adjacent muscles and held in position by layers of dense connective tissue called fascia
tendon
a flexible but inelastic cord of strong fibrous collagen tissue attaching a muscle to a bone.
aponeuroses
a sheet of pearly white fibrous tissue that takes the place of a tendon in flat muscles having a wide area of attachment.
fascicles
a bundle of structures, such as nerve or muscle fibers or conducting vessels in plants.
epimysium
a sheath of fibrous elastic tissue surrounding a muscle.
perimysium
the sheath of connective tissue surrounding a bundle of muscle fibers.
difference of perimysium and epimysium
The perimysium is what surrounds groups of muscle fibers to form fascicle. The epimysium surrounds a collection of fascicles that comprise the muscle. The epimysium is the outermost skeletal muscle covering.
compartment
Compartment (anatomy), a space of connective tissue between muscles.
deep fascia
a layer of dense connective tissue that can surround individual muscles and groups of muscles to separate into fascial compartments. This fibrous connective tissue interpenetrates and surrounds the muscles, bones, nerves, and blood vessels of the body.
subcutaneous fascia
also known as the hypodermis or superficial fascia, is the layer of tissue that underlies the skin.
sarcolemma
the fine transparent tubular sheath which envelops the fibers of skeletal muscles.
cytoplasm
the material or protoplasm within a living cell, excluding the nucleus.
myofibrils
any of the elongated contractile threads found in striated muscle cells.
myosin
a fibrous protein that forms (together with actin) the contractile filaments of muscle cells and is also involved in motion in other types of cells.
actin
a protein that forms (together with myosin) the contractile filaments of muscle cells, and is also involved in motion in other types of cells.
troponin
Troponins are a group of proteins found in skeletal and heart (cardiac) muscle fibers that regulate muscular contraction.
tropomyosin
a protein involved in muscle contraction. It is related to myosin and occurs together with troponin in the thin filaments of muscle tissue.
Muscle Structures*
*Structures in order of increasing complexity- Thick and thin filaments Myofibril Muscle fiber Fascicle Muscle
titin
also known as connectin, is a protein that is encoded by the TTN gene in humans. Titin is a giant protein, greater than 1 µm in length, that functions as a molecular spring which is responsible for the passive elasticity of muscle in addition to keeping myosin molecules in place.
sarcoplasmic reticulum (SR)
is a membrane-bound structure found within muscle cells that is similar to the endoplasmic reticulum in other cells. The main function of the SR is to store calcium ions (Ca2+).
transverse tubules (T tubules)
are extensions of the cell membrane that penetrate into the centre of skeletal and cardiac muscle cells. Through these mechanisms, T-tubules allow heart muscle cells to contract more forcefully by synchronizing calcium release throughout the cell.
cisternae
A cisterna (plural cisternae) is a flattened membrane disk of the endoplasmic reticulum and Golgi apparatus. A Golgi stack may contain anywhere from three to twenty cisternae, but most contain about six cisternae. Golgi cisternae can be separated into four classes; cis, medial, trans, and TGN (trans-Golgi network).
A muscle fiber contraction
is a complex interaction of several cellular and chemical constituents. The result is a movement within the myofibrils in which the filaments of actin and myosin slide past one another, shortening the sarcomeres.
synapse
Each cell that a neuron controls is connected functionally (but not physically) to the end of an axon, in much the same way that you can talk into a cell phone although your mouth is not in direct physical contact with it. The site of this functional connection is called a synapse.
neurotransmitters
Neurons communicate with the cells that they control by releasing chemicals, called neurotransmitters (nu″ro-trans-mit-erz), at a synapse.
motor neurons.
a nerve cell forming part of a pathway along which impulses pass from the brain or spinal cord to a muscle or gland.
neuromuscular junction (myoneural junction)
is a chemical synapse between a motor neuron and a muscle fiber. It allow the motor neuron to transmit a signal to the muscle fiber, causing muscle contraction. Muscles require innervation to function—and even just to maintain muscle tone, avoiding atrophy.
motor end plate
are specialised chemical synapses formed at the sites where the terminal branches of the axon of a motor neuron contact a target muscle cell.
synaptic cleft
A small gap called the synaptic cleft separates the membrane of the neuron and the membrane of the muscle fiber.
Acetylcholine (ACh)
is the neurotransmitter that motor neurons use to control skeletal muscle contraction. ACh is synthesized in the cytoplasm of the motor neuron and is stored in synaptic vesicles near the distal end of its axon.
excitation-contraction coupling
is the process by which an electrical stimulus triggers the release of calcium by the sarcoplasmic reticulum, initiating the mechanism of muscle contraction by sarcomere shortening.
Clostridium botulinum
in an anaerobic (oxygen-poor) environment, such as in a can of improperly preserved food, it produces a toxin. If a person ingests the toxin, the release of acetylcholine from axon terminals at neuromuscular junctions is prevented. Symptoms of such food poisoning include nausea, vomiting, and diarrhea; headache, dizziness, and blurred or double vision; and finally, weakness, hoarseness, and difficulty swallowing and, eventually, inability to breathe.
myasthenia gravis (MG) “grave muscular weakness”
The body produces antibodies that target receptors for the neurotransmitter acetylcholine on skeletal muscle cells at neuromuscular junctions. People with MG have one-third the normal number of acetylcholine receptors on their skeletal muscle cells. On a whole-body level, this causes weak and easily fatigued muscles.
acetylcholinesterase (AChE)
also known as AChE or acetylhydrolase, is the primary cholinesterase in the body. It is an enzyme that catalyzes the breakdown of acetylcholine and of some other choline esters that function as neurotransmitters.
creatine phosphate (PCr)
is a phosphorylated creatine molecule that serves as a rapidly mobilizable reserve of high-energy phosphates in skeletal muscle, myocard and the brain to recycle adenosine triphosphate, the energy currency of the cell.
myoglobin
a red protein containing heme, which carries and stores oxygen in muscle cells. It is structurally similar to a subunit of hemoglobin. (heme-an iron-containing compound)
lactic acid threshold
Lactate threshold is defined as the intensity of exercise at which lactate begins to accumulate in the blood at a faster rate than it can be removed.
oxygen debt,
or excess post-exercise oxygen consumption (EPOC)
is the amount of oxygen required to restore your body to its normal, resting level of metabolic function (called homeostasis).
anaerobic exercise
is any activity that breaks down glucose for energy without using oxygen. Generally, these activities are of short length with high intensity. The idea is that a lot of energy is released within a small period of time, and your oxygen demand surpasses the oxygen supply.
fatigue / Muscle (MM) fatigue
is a symptom that decreases your muscles’ ability to perform over time. It can be associated with a state of exhaustion, often following strenuous activity or exercise. When you experience fatigue, the force behind your muscles’ movements decrease, causing you to feel weaker.
cellular respiration / MM heat production
All active cells generate heat, which is a by-product of cellular respiration. Muscle tissue constitutes such a large proportion of total body mass that it is a major source of heat.
threshold stimulus
is the weakest stimulus that could generate an action potential in a neuron.
twitch
The contractile response of a single muscle fiber to a single impulse is called a twitch. A twitch consists of a period of contraction, during which the fiber pulls at its attachments, followed by a period of relaxation, during which the pulling force declines.
summation
Twitch summation or treppe is the addition of a second twitch, resulting in greater tension, and it results from stimulating the muscle before it has a chance to relax completely.
tetany
Tetany or tetanic seizure is a medical sign consisting of the involuntary contraction of muscles, which may be caused by disorders that increase the action potential frequency of muscle cells or the nerves that innervate them.
recruitment
Motor unit recruitment refers to the activation of additional motor units to accomplish an increase in contractile strength in a muscle. A motor unit consists of one motor neuron and all of the muscle fibers it stimulates.
The higher the recruitment the stronger the muscle contraction will be.
muscle tone (tonus)
is the continuous and passive partial contraction of the muscles, or the muscle’s resistance to passive stretch during resting state. It helps to maintain posture and declines during REM sleep.
concentric contraction
is a type of muscle activation that causes tension on your muscle as it shortens. As your muscle shortens, it generates enough force to move an object. This is the most popular type of muscle contraction. In weight training, a bicep curl is an easy-to-recognize concentric movement.
eccentric contraction
occurs when the total length of the muscle increases as tension is produced. For example, the lowering phase of a biceps curl constitutes an eccentric contraction. Muscles are capable of generating greater forces under eccentric conditions than under either isometric or concentric contractions.
isometric contractions (equal length—change in force)
generate force by changing the length of the muscle and can be concentric contractions or eccentric contractions. A concentric contraction causes muscles to shorten, thereby generating force.
Isometric contractions generate force without changing the length of the muscle.
multiunit smooth muscle
in the walls of the viscera, called visceral muscle, has a stress-relaxation response that permits muscle to stretch, contract, and relax as the organ expands. Multiunit smooth muscle cells do not possess gap junctions, and contraction does not spread from one cell to the next.
Visceral smooth muscle (single-unit smooth muscle)
Single-unit smooth muscle, or visceral smooth muscle is a type of smooth muscle found in the uterus, gastro-intestinal tract, and the bladder. In SUVSM, a single smooth muscle cell in a bundle is innervated by an autonomic nerve fiber.
rhythmicity
a pattern of spontaneous repeated contractions.
peristalsis
the involuntary constriction and relaxation of the muscles of the intestine or another canal, creating wave-like movements that push the contents of the canal forward.
Peripheral Resistance
is the resistance of the arteries to blood flow. As the arteries constrict, the resistance increases and as they dilate, resistance decreases. Peripheral resistance is determined by three factors: Autonomic activity: sympathetic activity constricts peripheral arteries.
calmodulin
(CaM) (an abbreviation for calcium-modulated protein) is a multifunctional intermediate calcium-binding messenger protein expressed in all eukaryotic cells. It is an intracellular target of the secondary messenger Ca2+, and the binding of Ca2+ is required for the activation of calmodulin.
norepinephrine
is a naturally occurring chemical in the body that acts as both a stress hormone and neurotransmitter (a substance that sends signals between nerve cells). It’s released into the blood as a stress hormone when the brain perceives that a stressful event has occurred.
Cardiac muscle also known as myocardiocytes
Cardiac muscle tissue is a specialized, organized type of tissue that only exists in the heart. It is responsible for keeping the heart pumping and blood circulating around the body. Cardiac muscle tissue, or myocardium, contains cells that expand and contract in response to electrical impulses from the nervous system
syncytium
BIOLOGY
a single cell or cytoplasmic mass containing several nuclei, formed by fusion of cells or by division of nuclei.
EMBRYOLOGY
syncytium forming the outermost layer of the trophoblast.
intercalated discs
are unique structural formations found between the myocardial cells of the heart. They play vital roles in bonding cardiac muscle cells together and in transmitting signals between cells.
Whenever limbs or other body parts move, bones and muscles interact as simple mechanical devices called -
levers
origin of the muscle
The origin is the attachment site that doesn’t move during contraction,
insertion of the muscle
insertion is the attachment site that DOES move when the muscle contracts.
agonist
causes an action