Term
Functions of Skeletal System |
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Definition
| Support, protection movement mineral storage blood cell production and fat storage |
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Term
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Definition
A kind of connective tissue.
Crystals of inorganic calcium salts make it more rigid than other connective tissues.
Network of collagen fibers provides flexibility and strength. |
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Definition
Frame work of bones and cartilage composed of various tissues
Bone, Cartilage, Epithelium, Fat, and Neurons |
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Term
| Compact or dense bone tissue |
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Definition
Contains few spaces.
Forms a layer over spongy bone.
Provides protection support and strength.
Has a concentric ring structure. |
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Term
| Spongy or cancellous bone tissue |
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Definition
Contains many large spaces
Makes up most of the bone tissue of the skull bone, vertebrae and the Epiphyses or “tip” of long bone
Lattice works of thin bone plates are called trabeculae
In some bones the spaces are filled with red marrow which produces blood cells
provides the greatest strength with the least weight
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Term
| Parts of a typical long bone |
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Definition
| Diaphysis, Epiphysis, Metaphysis |
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Definition
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Definition
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Definition
Region of the bone that connects the epiphysis to the diaphysis
Also contains the episyseal plate (where bone growth occures |
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Term
| Medullary or marrow cavity |
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Definition
Space within the diaphysis
Contains fatty yellow marrow in adults |
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Term
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Definition
| Layer of osteoblast lining the marrow cavity and scattered osteoclast |
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Definition
| bone cell that makes the bone |
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Definition
| Bone cell that degrades the bone |
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Definition
| Thin layer of cartilage covering the epiphysis at a joint with another bone |
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Definition
Fibrous covering around the bone where it is not covered by articular cartilage
Which Consist of Connective tissue containing blood vessels, Lymphatic vessels, Nerves, and Cells that become osteoblast |
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Term
Osteons or haversian system (functional units of the bone) |
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Definition
Structural unit of bone
Elongated cylinder parallel to bones long axis
Function as weight bearing pillars
Osteons is a hollow tube of bone Like rings on a tree, the rings are called lamella.
Collagen fibers in adjacent lamella run in opposite directions
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Term
| Central or haversian canals |
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Definition
Canal that runs through the center of the osteons
Contains small blood vessels and Nerve fibers |
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Term
| Perforation of Volmann’s canals |
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Definition
Lie at right angles to the central canal
Connect nerves and blood vessels in central canals with rest of the body (perpendicular to the long axis of the bone) |
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Term
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Definition
Mature bone cells that is found in lacunae at the junctions of the lamellae
Canaliculi connect lacunae |
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Definition
Located on the outside or surface of the shaft
Surround the osteons inside of the bone
Like bark on a tree |
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Term
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Definition
Bone formation
Embryo begins with a ‘skeleton’ of cartilage and fibrous membranes shaped like bones
begins about 6-7 weeks right after conception and continues throughout adulthood
Embryonic connective tissue cells multiply and enlarge and form cartilage and bone
Once a framework is made, calcification occurs, Calcium is deposited making the bone hard |
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Term
| Order of Ossification in Long Bone |
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Definition
Shaft ossifies first
Epiphyses ossify secondarily
Epiphyseal plate between the shaft and ends remains cartilage
`Permits growth of the bone shaft
When lengthening stops the epiphyseal plate becomes the epiphyseal line |
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Definition
| Bones also increase in diameter during this |
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Definition
| Constantly, which allows bones and blood to exchange calcium |
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Definition
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Definition
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Definition
| Calcium, Phosphorus, Vitamin D |
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Term
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Definition
| Growth hormone, Calcitonin, Parathyroid hormone, and Serotonin |
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Term
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Definition
| Pituitary gland in the brain, Regulates general body growth |
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Definition
| Thyroid gland in the throat, it promotes calcium deposistion into the bone |
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Definition
| In the throat, Promotes removal of calcium from the bones, Osteoclast |
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Term
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Definition
Made in the intestine, its a neurotransmitter, it also inhibits osteoblast production
Shifts balance to the osteoclast, helping with bone degradation |
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Term
| When blood concentration of Ca2+ is too high |
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Definition
the Rising blood levels of stimulate calcitonin release
Calcitonin stimulates the osteoblast to deposit Ca2+ into the bones
Ca2+ Concentration of blood returns to the homeostatic level
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Term
| When blood concentration of Ca2+ is too low |
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Definition
Falling Ca2+ levels stimulate parathyroid hormone release
Hormone stimulates osteoclast to degrade the bond
Ca2+ is released into the blood
Ca2+ levels in blood increase to the homeostatic level
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Term
| Remodeling and mechanical factors |
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Definition
Functions to strengthen parts of the skeleton that are under stress
Not sure how it occures..may involve locally produced growth factors that stimulate the osteoblasts
Aging shifts the balance between organic matter and calcium in bones
More inorganic salts and less organic matter
Causes less flexible and more brittle bones |
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Term
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Definition
| Wide and oval-shaped pelvic opening, small eyebrow ridge |
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Definition
Narrow pelvic opening and its heart-shaped
Thicker skulls
Dominate eyebrow ridge |
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Term
| What bones can tell you, Age |
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Definition
Different bones have specific times that they stop growing
Teeth erupt at specific ages
Tooth wear |
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Term
| Other Info that bones can tell you |
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Definition
Based on minerals incorporated into bones:
Diet
Location person grew up based on the proportions of isotopes in the bones |
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Term
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Definition
| Muscle size and activities of a person |
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Term
| Muscles make up how much body weight |
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Definition
| 30-50% and there are over 600 skeletal muscles in the body |
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Term
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Definition
Excitability - response to a stimulus
Contractility - ability to contract
Extensibility - ability to extend
Elasticity - ability to stretch
Conductivity - a muscle can conduct a nerve impulse from one muscle to another |
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Definition
| Motion, Maintenance of posture, and hear production |
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Term
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Definition
Attached to bones, (for the most part) and moves parts of the skeleton
Makes up what we usually think of as muscle |
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Term
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Definition
Very long (ten times the normal size)
Cylindrical fibers - cylinder like
Multi-nucleated (large cells)
Have prominent striations |
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Term
| Skeletal Muscle Contractions |
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Definition
Slow to fast
Forceful
Not rhythmic (unless your mind tells them too)
Voluntary |
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Term
| Skeletal Externally Visible Movments |
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Definition
Locomotion - walking running
Grasping with fingers
Respiration and Swallowing
Food manipulation and speech
Expression of mood and emotion |
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Term
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Definition
Superficial fascia
Deep fascia |
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Term
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Definition
Lies just under the skin
Composed of adipose and loose connective tissue
Stores fat and water
Insulates the body (the fat)
Provides mechanical protection from blows
Pathway for blood vessels and nerves |
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Definition
Lines the body wall and surrounds groups of muscles
Allows free movement of muscles
Pathway for nerves and blood vessels
Sometimes it is the origin for muscles
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Term
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Definition
Cords of fibrous connective tissue
Attach a muscle to a bone, they are not very elastic
Tendons pull bones in the direction of the contraction
Important in the hands and feet
`Permit a highly mobile appendage without the bulk of muscles
Ligaments are like tendons except they connect bone to bone
` Joint
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Term
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Definition
A broad, flat sheet of dense connective tissue
Join two or more muscles together, or to a bone
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Term
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Definition
Muscle cells, Long cylindrical cells visible under a microscope, Each fiber is surrounded by a sheath of connective tissue Largest cells (10x average size cells) Contain multiple nuclei
The cytoplasm is the sarcoplasm (sarco = muscle)
Myoglobin - a molecule that stores oxygen in muscles (also makes the muscle red or pink)
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Term
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Definition
Muscles are arranged in a series of bundles
`Small to large
Endomysium, Perimysium, Epimysium, |
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Term
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Definition
Surrounds a single myofiber
Contains:
Blood capillaries
Nerve fibers
They^ nourish and stimulate the cell |
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Term
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Definition
Surrounds the fascicles (bundles of muscle cells)
Carries larger blood vessels and nerves |
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Term
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Definition
| Surrounds several fascicles that together compose a muscle, Separates a muscle from the surrounding muscles or tissues, Carries blood vessels and nerves |
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Term
| Myofibrils (Second Largest) |
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Definition
Rod like super-organelles (only found in muscle cells) Oriented lengthwise and parallel the length of the cell Contractile elements of muscle cells
Composed of smaller contractile units called sarcomeres (entire row on the ceiling is one myofibrils, each individual tile is the sarcomeres)
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Term
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Definition
Series of light and dark bands along the length of the myofibril
A bands - dark bands
I bands - light bands
H zone - a light stripe in the middle of the A band
Z disk - dark midline of the I band
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Term
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Definition
Functional unit of the muscle fiber
Part of a myofibril that is between two Z disks
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Term
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Definition
Are structures within the sarcomere
` There are two kinds (Thick and Thin) |
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Term
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Definition
Go across the A band, Made of myosin
Myosin -- A protein with a rod like tail end and two globular heads on the other end
Globular heads are called cross bridges
`Link the thick and thin filaments together during contractions
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Term
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Definition
Cross the I band and extend into the A band
Made of
Actin,Troponin,Tropomyosin |
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Term
| Sarcoplasmic Reticulum (SR) |
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Definition
Smooth ER
Regulates intracellular calcium levels (Ca2+)
Stores Ca2+ when the muscles is not contracted
Releases Ca2+ when the muscle is contracted
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Term
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Definition
Transverse tubules, Folds of the cell membrane that penetrate the cell, Oriented at right angles to the myofilaments, Functions to synchronize muscle contractions
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Term
| Skeletal muscle contractions |
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Definition
| During contraction individual sacromeres shorten causing the cell to shorten Thick and thin filaments do not change length They ^ slide past each other In a relaxed myofiber the thick and thin filaments slightly over lap, During contractions the thin filaments slide in a contracted myofiber they overlap to a much greater degree |
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Term
| Sliding of the think filaments |
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Definition
Sliding of the think filaments
Nerve impulse stimulates the release of Ca2+from the SR
Increases the intracellular Ca2+ concentration
Ca2+ binds to troponin
Troponin changes shape, Causing tropomyosin to slide
Which exposes the myosin binding site on actin
Myosin cross bridge attach to the myosin binding site on actin
Cross bridges attach and detach many times
---Acts like a ratchet pulling the thin filament inwards
Action continues as long as the Ca2+ concentration is high |
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Term
| Steps in Skeletal Muscle Contraction |
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Definition
| Cross bridge attachment, Power Stroke, Cross bridge detachment, Cocking of the myosin head, |
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Term
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Definition
Activated myosin heads are attached to the myosin binding sites
Cross bridge binding occurs |
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Term
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Definition
Occurs when the myosin head binds to the actin:
a: Myosin pivots ,b: Changes from a high energy shape to a low energy shape
Pivoting of the myosin head pushes the thin filaments towards the sarcomeres center
Simultaneously ADP & P are released from the myosin head, ADP & P are left over from the previous contraction
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Term
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Definition
A new ATP molecule binds to the head
Causing it to change shape
Head is released from the myosin binding site on actin
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Term
| Cocking of the myosin head |
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Definition
Myosin head is cocked by converting ATP to ADP & P
Provides the potential energy for the contraction
ADP & P remain attached to the myosin head in this step |
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Term
| Back Where We Started (Cross Bridge Attachment) |
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Definition
Myosin head is ready for a cycle, Continuing process moves the thin filament towards the sarocomeres center, The thin filament does not slide bak when a single myosin head detaches, Some myosin heads remains attached
Muscles relaxes when calcium is pumped back into the SR
Troponin resumes its normal shape, Causes tropomyosin to slide and cover the myosin cites on actin |
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Term
| Regulating of binding contracting |
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Definition
An action potential is required for a skeletal muscles contractions and action potential (AP) = nerve impulse = electrical current
AP causes a temporary rise in the intracellular Ca2+ concentration
The rising Ca2+ concentration stimulates the contraction |
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Term
| Neuron muscular junction and the nerve impulse |
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Definition
Skeletal muscles are stimulated by motor neurons
Motor neurons are in the brain and are connected to muscles by axons
An axon is the arm of the neuron that carries a nerve impulse away from a nerve cell body, Axons are bundled into nerves, Axons subdivide when they enter a muscle and innervate different parts of the muscle, The axon terminal forms a neuromuscular junction with a single muscle fiber, Axon terminal does not touch the muscle fiber Axon terminal contains synaptic vesicles filled with acetylcholine, Acetylcholine is a neurotransmitter, Carries the AP across the synapsis,
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Term
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Definition
| Area of close contact between nerve and muscle |
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Term
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Definition
| Space between the axon and the muscle fiber |
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Term
| When an AP reaches the axon terminal |
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Definition
Ca2+ Enters the axon
Ca2+ stimulates the exocytosis of acetylcholine
Acetylcholine diffuses across the synaptic cleft
Binds with receptors on the sarcolemma (muscle cell membrane)
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Term
| Muscle cell AP and contraction |
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Definition
Acetylcholine binds wit the muscle cell membrane
AP is stimulated on the membrane AP travels down the t-tubules, AP stimulates the release, of Ca2+ from the SR
Ca2+ causes the active sites on actin to become uncovered Ca2+ fall within 30 ms, An active Ca2+ pump moves Ca2+ back into the SR, When the Ca2+ fall sufficiently
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Term
| Ca2+ causes the active sites on actin to become uncovered |
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Definition
Ca2+ causes troponin to change shape
Causes tropomyosin to slide exposing the myocin binding site
Cross bridge attachment occurs |
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Term
| When the Ca2+ fall sufficiently |
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Definition
Troponin assumes its normal shape
The actin myosin binding sites are covered and made unavailable |
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Term
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Definition
Composed of the motor neuron and the muscle fibers that it innervates, Each muscle has at least one motor nerve with up to 100’s of axons, Each axon branches into many axon terminals, Each terminal forms a neuromuscular junction with a single muscle fiber, Stimulating a motor neuron causes all of the innervated muscle fibers to contract
Muscles with very fine movements have very small motor units |
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Term
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Definition
A single brief stimulus which causes a muscle to quickly contract than relax
Muscle twitches are rarely observed
`Eye muscle twitch
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Term
| Graded muscle show a graded response |
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Definition
Most muscles show a graded response
Contractions that are long, smooth and very in strength Produced in two ways
Changing the speed of stimulation
Changing the number of motor units activated |
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Term
| Wave summation and tetanus |
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Definition
If a muscle is stimulated by two identical stimuli
The second stimulus will cause a stronger contraction, Because the muscle is not completely relaxed after the first contraction, Ca2+ must still be inside the cells cytoplasm
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Term
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Definition
Is stimulated increasingly faster
Relaxation time between contractions becomes less
Ca2+ concentration inside the cytoplasm will continue to increase |
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Term
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Definition
is the continual smooth contraction of a muscle
Contraction continues until the muscle is fatigued and looses its ability to contract
Due to the loss of the muscles ability to generate ATP
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Term
| Multiple motor units summation |
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Definition
Precisely controls the force of a muscle contraction
Enables the fine control of the strength of the contraction, `Accomplished by activating different numbers of fibers, Only a few motor units are stimulated for weak but precise movements
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Term
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Definition
Skeletal muscles are in a constant state of slight contraction
Functions:
Keep muscles healthy but not produce movement
Stabilizes joints and maintains posture |
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Term
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Definition
Muscle tension
Isotonic contraction (moving something)
Isometric contractions |
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Term
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Definition
Force generated by o contracting muscle on some object, Load - resistance to movement in opposition to force, Muscle tension > muscle load
The object is moved
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Term
| Isotonic contraction (moving something) |
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Definition
--Muscle changes in length
For example it decreases the angle at the joint
Thereby moves the load
Tension remains constant during contraction
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Term
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Definition
Tension continues to increase during contractions
Muscle does not get any longer of shorter
Functions to hold something in place
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Term
| Muscle cramps = Charley horse |
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Definition
Sudden involuntary contractions or spasms of muscles
Often occur after workouts or at night
Last a few seconds to several minutes |
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Term
| Physiological mechanism of Muscle Cramps |
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Definition
Caused by explosive hyperactivity of motor nerves
Several mechanisms, Spinal disinhibition
Abnormal excitability of the axon terminals
Spreading of muscle contraction by direct transmission or axon reflexes |
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Term
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Definition
Its unknown, Straining or over using of a muscle
Dehydration, Imbalances in levels of sodium potassium chloride calcium and phosphate
Insufficient blood getting to muscle
Insufficient stretching before exercise
Exercising in the heat, Muscle fatigue spinal cord injury or a pinched nerve in the neck or back
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Term
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Definition
ATP provides the energy for the contractions
Their is only 4-6 seconds worth of ATP help in reserve in muscles
More APT is generated in 3 ways |
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Term
| Activation of ADP by creatine phosphate |
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Definition
A high energy molecule store in muscles
Small amino acid like molecule
Used to phosphorylate ADP
Stored ATP & creation phosphate supply enough energy for about 15-20 seconds of contractions |
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Term
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Definition
ATP is obtained from the breakdown of glucose or other energy yielding molecules
Glucose will come from glycogen
Process yield - 36 ATP per glucose molecule
O2 and other molecules must be present
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Term
| Anaerobic respiration (or metabolism) |
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Definition
First stage of glucose respiration, Process is know as glycolysis
Splits one molecule of glucose into 2 molecules of pyruvic acid, Net yield of 2 ATP, Process does not use O2, Pyruvic acid is broken down into Co2 and water during aerobic respiration, After prolonged exercise O2 demand does not equal oxygen supply, If O2 is lacking pyruvic acid its converted into lactic acid, Muscles become fatigued
They are not getting enough ATP to continue to contract
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Term
Fatigue occurs when muscles are physiologically unable to contract
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Definition
Occurs when there is a relative deficit of ATP
A total absence of ATP results in a constant state of contraction, because ATP required to release the myosin heads from actin
Rigor morit |
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Term
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Definition
Exact cause is uncertain
Inadequate release of Ca2+ from SR
Insufficient O2
Glycogen and glucose depletion
Lactic acid and ADP build up |
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Term
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Definition
| Lactic acid and ion imbalances are partially responsible |
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Term
| For muscle to return to its resting state |
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Definition
Normal O2 concentration of the muscle must be restored
All of the lactic acid must be converted back into
Glycogen, and Glucose |
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Term
Force of a contraction is affected by |
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Definition
The number of muscle fibers stimulated
The relative size of muscles diameter and length
Series elastic elements |
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Term
| For a muscle to work requires |
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Definition
Muscle must be attracted to a moveable object
Connective tissues and tendons must be pulled tight
The more rapidly a muscle is stimulated the greater force it generates`` because it takes less time to transfer the force to the series - elastic elements, When the contractions is slow --Forces dissipated before it can be transferred to the series- elastic elements |
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Term
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Definition
Ideal resting length is when the myosin and actin fibers barely overlap, Can be greatly compressed
Significant overlap produces the distance the muscle can contract
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Term
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Definition
Muscles are attached on both ends so they always have a load, Lighter the load the faster the contraction, Larger the load the slower and shorter the contraction
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Term
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Definition
Energy primarily from aerobic respiration
Lots of mitochondria, Rich capillary supply
Fatigue resistant and high endurance
Fibers are thin so they don't generate much power
Lots of myoglobin
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Term
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Definition
White or pale have little myoglobin, More powerful that red fibers, ‘-Twice the diameter of red fibers
Few mitochondria, Lots of stored glycogen
Energy is from anaerobic metabolism
Fatigue very quickly, Very rapid and intense contractions |
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Term
| Intermediate fast twitch fibers |
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Definition
Red or pink, Diameter of the fibers in intermediate
Fast acting fibers like in white muscle
More dependent on myoglobin Have more myoglobin
Lots of capillaries, Uses aerobic metabolism
Fatigue resistant ``(they are fast acting like red muscle but need more oxygen)
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Term
| Fibers and microscopic structure of Smooth Muscles |
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Definition
Smooth spindle shaped cells with a single nucleus in the center
Organized into two layers of cells
Exhibit peristalsis |
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Term
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Definition
Alternating contraction of the two layers
Moves a substance down a tubem, EsophagusControlled by the autonomic nervous system, Lack T tubules, SR connects directly to the cell membrane, APs directly stimulate the SR to release Ca2+ Lacks striations
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Term
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Definition
Moving substances through body passages
Expulsion of stored substances
regulation of the size of openings (like the pupils)
Regulation of the diameter of tubes |
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Term
| Smooth Muscles Lack Striations |
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Definition
No sarcomeres
Thick and thin filaments spiral down the cells length
Myosin has more actin gripping heads
Permits equal power to skeletal muscle
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Term
| Contraction of Smooth Muscle |
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Definition
Slow synchronized contractions, Coordination is by hollow cylinders called gap junctions, `Permits direct movement of AP’s between adjacent cells, Some cells act as pacemakers (set the rhythm of the contraction) Contraction is like skeletal muscle contraction Slow fatigue resistant sustained contractions, Takes 30x longer to contract than skeletal muscle
Can stay contracted for longer periods with less energy that skeletal muscle, Have low energy requirements
Most ATP is made anaerobically, Regulation of contraction is similar to skeletal muscle with both electrical and chemical stimulation |
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Term
| Contraction of Smooth Muscle is like skeletal muscle contraction |
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Definition
Actin and myosin interact
Contraction caused by intracellular calcium
ATP provides the energy |
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Term
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Definition
All muscles respond with more intense contractions when stretched
In smooth muscle stretching moves materials along a passageway |
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Term
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Definition
Increased tension lasts for a short while
Smooth muscle returns to its normal tension in a few minutes, Permits an organ lined with smooth muscles to fill or slowly expand, Enables slow movement of substances through a tube
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Term
| Length and tension changes |
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Definition
Smooth muscle can stretch more that skeletal muscle
Corkscrew like nature of the myosin permits more overlap between the thick and thin filaments |
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Term
Length and tension changes Permits smooth muscle to:
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Definition
Stretch when needed
Be thin when needed
All without making the muscle flabby when empty
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Term
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Definition
Smooth muscles fibers are able to divide and reproduce, Important when an increase in the size of an organ is needed, Uterus during pregnancy
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