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A & P Hopkins Exam 3
A & P Hopkins Lecture Exam 3 Final
| Question | Answer |
|---|---|
| How many bones are in the body? | 206 that are counted |
| What are the 5 classifications of bones? | Long, short, flat, irregular and sesamoid |
| Where do you typically find long bones? | extremities e.g. forearm and thigh and phalanges |
| Where do you typically find short bones? | ankles and wrists (they are cubelike) carpals, tarsals |
| Where do you typically find flat bones? | skull (they are platelike and are found in ribs, scapulae, and some bones of the skiull) no epiphysis-grow once and done |
| Where do you typically find irregular bones? | they have a variety of shapes and are found in the vertebrae and many facial bones e.g. sphenoid |
| Where do you typically find sesamoid bones? | they are also called round bones and are usually small and embedded in tendons adjacent to joints. The knee cap (patella) is counted the sesamoid bones of the thumb and big toe are not counted. Job is to keep temdons in the groove. |
| What do you call the ends of long bones? | The epiphysis. The end closer to the trunk is proximal and the end further from the trunk is distal. The epiphysis articulates (forms a joint) with another bone. |
| What do you call the shaft of long bones? | The diaphysis. |
| What type of bone is found on the outside of all bones? | Compact bone (thin over epiphysis, thick over diaphysis) |
| What type of bone is found on the interior of bones? | Spongy bone a.k.a. cancellous bone (mostly in epiphysis but there is a thin layer before medullary cavity in diaphysis) |
| What do you call the point where two bones meet? | The articular surface |
| What is the articular surface made of? | Articular cartilage ( a form a hyaline cartilage) (is well lubricated by synovial membrane) |
| What is the name of the sheet of protective connective tissue found on the outside of bones? | periosteum it is tough and vascular, firmly attached to bone as well as ligaments and tendons. Helps in bone repair. |
| What is the name of the sheet of protective connective tissue found INSIDE bones? | endosteum (a thin membrane containing bone forming cells)The endosteum is filled with marrow. Lines central canal and medullary cavity. |
| What is the name of the hollow space inside long bones that contains bone marrow? | medullary cavity (which is lined with endosteum) |
| What type of marrow produces blood? | RED |
| What is yellow marrow made of? | FAT that replaced red marrow that is no longer needed. |
| What type of bone looks solid to the naked eye? | compact bone |
| What type of bone has spaces that can be seen with the naked eye? | spongy bone a.k.a. cancellous bone |
| Does compact bone have living cells? | YES - compact bone has living cells within the bone matric and it is very vascular. |
| What is the basic unit of compact bone? | osteon |
| What do you call bony projections on bones? | processes |
| What do you call the many branching bony plates found within spongy bone? | trabeculae "interconnecting rods". irregular branching contributes to the bone's strength and is more highly developed in epiphysis due to compressive forces. Adds strength w/out adding weight(trabeculae have lacunae and canaliculi but no central canals.) |
| What are bone cells called? | osteocytes |
| Where do osteocytes live? | In lacunae (tiny, bony chambers within bone matrix) |
| How are lacunae arranged? | In concentric circles around central canals aka Haversian canals |
| How do osteocytes transport nutrients and wastes? | They have cellular processes that pass through canaliculi. |
| What is the extracellular matrix of bone tissue made up of? | collagen (for strength) and organic salts (for hardness) Hopkins said mineral and protein substance around osteocytes. |
| What is inside the central canal? | small blood vessels and nerve fibers (central canals run longitudinally through bone) it is lined with endosteum |
| What do you call the larger canals running transverse/horizontal that connect the blood supply to the central canals? | perforating canals aka Volkmann's canals |
| Does trabeculae in spongy bone have blood vessels? | NO. Spongy bone doesn't need blood vessels like compact bone does. Spongy bone's access to blood supply is good. |
| Are bone tissues mainly inactive? | NO. They are always remodeling and using energy to maintain themselves. They respond to current stresses on the bones. |
| What are canaliculi? | small canals connecting the lacunae. The canaliculi will continue to grow until it meets up with another cell/osteocyte |
| What type of bone is located where stresses are limited in direction? | compact bone |
| What type of bone is located where stresses are weaker or multidirectional? | spongy bone (need strength in more directions around joints than in the middle of long bones) |
| Are solid structures or hollow cylinders stronger? | hollow structures. Medullary cavity makes bones stronger. |
| Why is the femur wider at the distal epiphysis/knee joint? | To distribute weight across the knee joint |
| What does ossification mean? | bone formation |
| What are intramembranous bones? | The broad, flat bones of the skull (not mandible)(They grow between sheets of connective tissue) |
| What is the name of the process that replaces connective tissue to form an intramembranous bone? | intramembranous ossification - during the process bones originate between sheetlike layers of connective tissue and then differentiate. |
| What are endochondrial bones? | they make up most of the bones of the skeleton. |
| What is endochondrial ossification? | They begina as model made of hyaline cartilage and then the cartilage converts to bone mineral. |
| What is the primary ossification center in an endochondrial bone? | It is the diaphysis (shaft) |
| What is the secondary ossification center in an endochondrial bone? | The epiphyses |
| What is the epiphyseal plate? | a band of cartilage that remains between the 2 ossification centers. This portion or the bone will continue growing up until puberty. |
| What happens after future bone cartilage cells begin to secrete mineral | the cartilage cells die after they calcify |
| How many layers do the cartilaginous cells of the epiphyseal plate make? | 4 |
| What are the characteristics of cells in the first layer of the epiphyseal plate? | resting cells, anchors epiphyseal plate to epiphysis (hyaline cartilage cells) |
| What are the characteristics of cells in the second layer of the epiphyseal plate? | cells are undergoing mitosis/proliferating (hyaline cartilage cells) |
| What are the characteristics of cells in the third layer of the epiphyseal plate | older cells, cartilage cells becoming calcified (hyaline cartilage cells) |
| What are the characteristics of cells in the fourth layer of the epiphyseal plate? | dead cells, calcified cartilage (hyaline cartilage cells) |
| What is the technical term for bone remodeling? | homeostasis of bone tissue. Bone is dynamic and always responds to change in activity. |
| What is the process called by which osteoclasts secrete acid and break down bone? | bone resorption |
| What hormone controls bone resorption? | parathyroid hormone |
| What is the process by which osteoblasts build bone? | bone deposition |
| What hormone drives bone growth as well as maintains calcium ions in blood? | calcitonin (also made by thyroid gland) |
| What does the term blast mean? | a young, metabolically active cell |
| What is vitamin C's affect on the skeletal system? | it strengthens all collagen fibers affecting bone, tendons, ligaments etc. |
| What will a deficiency in vitamin C produce? | fragile bones |
| What will a deficiency in vitamin A produce? | it will retard bone development |
| What will a deficiency in vitamin D produce? | rickets, osteomalacia (decreases bone density) |
| What will an insufficiency in growth hormone produce? | dwarfism (actually dwarfism is absence of growth hormone) |
| What will excessive growth hormone produce? | before puberty: gigantism, after puberty: acromegaly |
| How do sex hormones affect bone growth? | sex hormones promote bone formation, stimulate ossification at epiphyseal plates.(it stimulates the adolescent growth spurt and then somehow stops growth at the growth plate. Also maintains bone throughout life. This is why osteoporosis is r/t menopause) |
| How does physical stress (exercise) affect bone? | phys. stress/exercise stimulates bone growth and plays a role in maintaining bone strength |
| What are the 4 main functions of bone? | 1.support and protection (gives shape to head, protects lungs and eyes) 2. Movement (interacts with muscles, works as lever) 3. Blood cell formation (hematopoiesis for RBC's) 4. Inorganic salt storage (calcium, phosphate, magnesium, sodium, potassium) |
| What are the four basic components of levers? (only first two mentioned in review) | 1. rigid bar/bones 2. fulcrum (point on which bar moves)/joint 3. Object is moved against resistance 4. Force- supplues energy for movement/muscles |
| Our bones and joints are which class lever system? | Third (only one mentioned in review) |
| Possible extra credit: draw and label a long bone | include: epiphyseal plate, articular cartilage, diaphysis, epiphysis, periosteum, endosteum, medullary canal, spongy bone, compact bone, red and yellow marrow. |
| What is a facet? | small, smooth surface of a bone where articulation occurs (where joints are formed) |
| What are condyles? | rounded processes that are part of joints. Not all are equal. (from review) |
| What are some skeletal system lifespan changes? | decrease in height after 30, decrease in ca+, brittle bones, more osteoclasts than osteoblasts, bone loss rapid in menopause r/t estrogen, hip fractures, vertebral compression fractures=hump in elderly |
| What are the six types of fractures? | 1green stick:incomplete like splintering 2 fissured:incomplete longitudinal break 3 comminuted:complete fracture with bone fragments 4transverse:horizontal fracture 5oblique:not horizontal,other angles 6spiral:caused by excessive twisting e.g.abuse |
| What are articulations? | JOINTS |
| What are the major functions of joints? | junctions between bones, bind parts of skeleton together, make bone growth possible, permit shape change during childbirth, enable movement in response to muscular contraction. |
| What are the two ways we classify joints? | by STRUCTURE and by FUNCTION. All joints will have both classifications |
| What are the three structural classifications? | Synovial joints, Fibrous joints, Cartilaginous joints |
| What are the three functional classifications of joints? | diarthrotic (freely movable), amphiarthrotic (slightly movable) and synarthrotic (without arthrosis/immovable) |
| What is a fibrous joint? | dense connective tissue between 2 bones. |
| What are the three types of fibrous joints? | 1. syndemosis 2. suture 3. gomphosis |
| What are the characteristics of a syndemosis fibrous joint? | long fibers connect bones. amphiarthrotic (slightly movable) e.g distal ends of tibia and fibula |
| What are the characteristics of a suture fibrous joint? | thin layer of connective tissue between flat bones, synarthrotic (immovable)e.g. sutures in skull |
| What are the characteristics of gomphosis fibrous joints? | sheet of connective tissue between teeth and bones. Synarthrotic (immovable) |
| What are the characteristics of cartilagenous joints? | two bones connected by a piece of cartilage between them. |
| What are the two types of cartilagenous joints? | Synchondrosis (made of hyaline cartilage) Symphosis (made of fibrocartilage) |
| What are the characteristics synchondrosis cartilagenous joints? | bands of hyaline cartilage unite bones. Found in epiphyseal plate and also between manubrium and first rib. This type of joint is synarthrotic (immovable) |
| What are the characteristics of symphysis cartilagenous joints? | they are made of one piece/pad of fibrocartilage and examples are intervertebral disks and pubic symphysis (between pubic bones). They are ampiarthrotic, slightly movable. |
| Mobility vs stability | you give up strength in favor of mobility. The greater the range of motion the less strength. |
| What are the characteristics of synovial joints? | most are diarthrotic (freely movable), have a joint cavity, are lubricated with synovial fluid, the bones are connected by a joint capsule but are not attached at the point of contact. The synovial membrane secretes the synovial fluid. |
| Synovial joint: what is the articular capsule? | the fibrous capsule lined by synovial membrane. |
| Synovial joints: what are the characteristics of synovial fluid? | viscous slippery fluid rich in albumin and hyaluronic acid and similar to raw egg white. |
| Synovial joints: what are the characterisitics of the meniscus | it is a pad of fibrocartilage that absorbs shock, guides bone movements and distributes forces. |
| What do tendons do? | attach muscle to bone |
| What do ligaments do? | attach bone to bone |
| What is a bursa? | saclike extension of joint capsule which allows structures to slide more easily past eachother. Sac full of lubricating fluid. Inflamation of the bursa is bursitis. Most tendons have a sheet of bursa to eliminate friction. |
| What are the six types of synovial joints? | 1. ball-and-socket joints 2. condyloid joints 3. gliding joints 4. Hinge joints 5. Pivot joints 6. Saddle joints |
| What are examples of ball-and-socket synovial joints? | hip and shoulder. a lot of mobility and range of motion. |
| What are examples of condyloid synovial joints? | between metacarpals and phylanges. Oblong joint with a lot of mobility one way and limited in the other direction. |
| What are examples of gliding synovial joints? | between tarsals and carpals |
| What are examples of hinge synovial joints? | elbow and between phalanges (knee is a modified hinge joint) |
| What are examples of pivot synovial joints? | between proximal ends of radius and ulna (this is cool to try on your arm)between atlas and axis |
| What are examples of saddle synovial joints? | between carpal and metacarpal of thumb (2 complementary saddle like ends, one fits into another.) |
| What are the 8 types of joint movements? (1-5) | 1. abduction (take away)/adduction (add) 2. dorsiflexion (foot up)/plantarflexion (foot down) 3. flexion(hand down)/extension (hand flat)/hyperextension(bend hand up) 4. rotation/circumduction (can move 360)5. supination (soup)/pronation (pour it out) |
| What are the 8 types of joint movements? (6-8) | 6. eversion(move foot inward)/inversion(move foot outward) 7. protraction(move anteriorly-lean head forward)/retraction(move posteriorly- lean head backward) 8. elevation(move upward against gravity, shoulders up)/depression(move downward,shoulders down) |
| What are the characteristics of the shoulder joint? | ball and socket joint between head of humerus and glenoid cavity of scapula. Loose joint capsule with bursa, ligaments hold it in place and has wide R.O.M. |
| What are the characteristics of the elbow joint? | (no model in lab) hinge joint between trochlea of humerus and trochlear notch of ulna, also has a gliding joint between the capitulum of the humerus and the head of the radius. Provides for flexion and extension, stable joint. |
| What are the characteristics of hip joints? | ball-and-socket joint, the head of the femur fits into the acetabulum of the coxal bone, it has a heavy joint capsule with many reinforcing ligaments. Less freedom of movement than shoulder |
| What are the characteristics of knee joints? | largest joint and most complex, modified hinge joint, femur sits on tibia, has a patella, allows for flexion/extension but very little rotation, supported by many tendons and ligaments, has pad of cartilage called menisci, has bursae |
| What are the characteristics of intervertebral articulations? | they are gliding joints, lecture also said "symphyseal joints", cushioned by intervertebral discs (outer anulus fibrosis and inner nucleus pulposis), stabilized by ligaments. |
| What causes pain in a slipped disc? | pressure on spinal nerve |
| What are the three joint disorders discussed in class? | 1. sprains 2. bursitis 3. arthritis |
| What are the characteristics of sprains? | damage to cartilage, ligaments, or tendons associated with joints. Can be caused by forceful twisting of the joint |
| What are the characteristics of arthritis? | means inflamation of a joint, swollen, painful joints. Rheumatoid arthritis is systemic disease. Osteoarthritis is common in elderly. Gout caused by uric acid crystals deposited in joints. PT should avoid beer wine, organ meat. TX diet, proper hydration |
| What are the three types of muscle? | skeletal muscle, cardiac muscle and smooth muscle |
| What are the 5 functions of muscle? | 1. produce skeletal movement 2. maintain body posture and position 3. support soft tissues 4. guard entrances and exits (sphincters-internal smooth, external skeletal) 5. maintains body temperature |
| What are the characteristics of cardiac muscle tissue? | found only in heart,not under conscious control,striated,autorhythmic (will contract w/out input from cns), fibers are branched, cells attached at intercalated discs, have gap junctions, contractions last longer, longer refractory period(reset time) |
| What do gap junctions in cardiac tissue do? | they cause a group of fibers to contract as a unit. |
| Where are cardiac cells attached to each other? | at intercalated discs |
| Is there any connective tissue in muscle? | yes a lot. |
| What is the "action potential" in cardiac muscle? | the electrical impulse. It will spread throughout heart |
| Does the SA node receive impulse from the autonomic nervous system? | yes |
| Do all types of muscle cells have the same amount of sarcoplasmic reticulum? | NO. S.R. more developed in cardiac and skeletal, not smooth |
| What are the characteristics of smooth muscle cells? | short fibers, single nucleus, spindle shaped (elongated with tapered ends), myofilaments randomly organized(not in cardiac & skeletal), no striations, no transverse tubules, not well developed S.R. |
| How is smooth muscle contraction similar to to skeletal muscle contraction? | similar interactions between actin and myosin, both use calcium and ATP, both depend on impulses from nervous system |
| How is smooth muscle contraction DIFFERENT from skeletal muscle contraction? | 2 neurotransmitters affect smooth muscle: acetylcholine and norepi (only acetylcholine in skeletal), stretching can trigger smooth muscle contraction, smooth muscle slower to contract and relax, smooth muscle and cardiac muscle resistant to fatigue |
| Whick type of muscle is susceptable to fatigue? | skeletal |
| Does the term muscle refer to the cell or the organ? | both |
| What do you call muscle cells? | fibers |
| What are the characteristics of skeletal muscle? | organ of muscular system, has nervous tissue connected to it, has blood supply, has three types of connective tissue structures. |
| What are the six connective tissue structures in skeletal muscle? | fascia, tendon, aponeuroses, epimysium, perimysium and endomysium (many blood vessels and nerves run thru the connective tissue layers |
| What is fascia? | fascia separates each muscle fron the next, and holds the miuscle in place. It may extend into cordlike tendons. |
| What are tendons? | tendons are a cordlike extension of the fascia and may be attached to the periosteum of bone. (attaching muscle to bone) |
| What are aponeuroses? | broad fibrous sheets of connective tissue attaching muscle to muscle or muscle to bone. |
| What is epimysium? | layer of connective tissue that surrounds a skeletal muscle |
| What is perimysium? | layer of connective tissue that divides the muscle into sections/bundles called fascicles |
| What is endomysium? | is a very thin layer of connective tissue that surrounds each muscle fiber/cell |
| What is a fasicle? (plural fasciculus) | bundles of skeletal muscle fibers |
| What are the 5 divisions/levels of muscle tissue from outtermost to innermost? | muscle-fasicle-muscle fibers-myofibrils-thich and thin filaments |
| What are myofibrils? | thick filaments primarily composed of the protein myosin and thin filaments are primarily composed of the protein actin (troponin and tropomyosin are also types of thin filaments) |
| What are the parts of the muscle cell/fiber? | sarcolemma (muscle cell membrane), multi-nuclei, sarcoplasm (muscle cytoplasm), mitochondria, myofibrils (thick and thin filaments of myosin and actin) |
| what causes striations in skeletal muscle? | the organization of actin and myosin filaments . The striations form a repeating pattern called a sarcomere |
| what is a sarcomere? | striations that form a repeating pattern alone a muscle fiber. Muscles are basically collections of sarcomeres. (sarcomere is a functional unit of muscle tissue) |
| What are I bands? | the light bands in a sarcomere |
| What are A bands? | the dark bonds of a sarcomere |
| What is a sarcoplasmic reticulum? | it is the endoplasmic reticulum of muscle cell, per hopkins storage tank with ions |
| what are transverse tubules? | a set of membranous channels that extend into the sarcoplasm. each transverse tubule connects two enlarged portions of sarcoplasmic reticulum called cisterns (stprage tanks). |
| What is an M line? | The middle of one sarcomere |
| What is a Z line? | The end of each sarcomere |
| What is a triad? | it includes the S.R., transverse tubules and cisternae, and form the triad where the actin and myosin overlap |
| How do you know when the actin is at rest? | it is covered in tropomyosin so the myosin can't get to it. |
| What are the characteristics of thick filaments? | they always full towards the middle, they are composed of myosin protein, have cross bridges that act like hands that pull the thin filaments towards the middle - lack self control and will grap and pull forever if it can i.e. rigor mortis |
| What are the characteristics of thin filaments? | they are composed of the protein actin, they are associated with troponin and tropomyosin (also proteins). |
| Does one myosin filament grab one actin filament? | no, one myosin filament san grab several actin filaments (one actin filament can interact with up to three myosin filaments) |
| Are there the same amount of thick and thin filaments? | no, far more thin filaments. |
| What are the levels of organization in muscle tissue? | 1. skeletal muscle (surrounded by epimysium, containing fasicles) 2. muscle fasicle (surrounded by perimysium, contains muscle fibers) 3. muscle fibers (surrounded by endomysium, contains myofibrils) 4. myofibrils (surrounded by S.R. and contain sarcomere |
| What is the neuromuscular junction? | The junction between the nerve and the muscle cell. The site where the axon and muscle fiber communicate. aka synaptic cleft (the actualt space between the two) |
| What is the name of neurons that send messages OUT of the central nervous system? | motor neurons. They talk to muscles and glands |
| What is a motor end plate? | the specialized portion of the fiber membrane found at the neuromuscular junction/synaptic cleft |
| What is a synaptic vessicle? | sacs of neurotransmitters just inside the neuron's cell wall. |
| What is the neurotransmitter that motor neurons use to control skeletal muscles? | Acetylcholine (ACh) |
| What is the stimulus for contraction? | 1.the cns send a nerve impulse that causes release of ACh from synaptic vesicles. 2. The ACh binds to receptors in the motor end plate. 3. the ACh crosses the motor end plate, enters the muscle cell and depolarizes the membrane generating a muscle impulse |
| What is a muscle impulse? | an electrical signal similar to a nerve impulse...except it occurs in muscles. It changes the muscle cell membrane in such a way that it travels throughout muscle cell into transverse ubules, into sarcoplasm, into sarcoplasmic reticulum, and cisternae. |
| What does the sarcoplasmic reticulum contain? | high concentraions of calcium ions (Ca++). They get in there by active transport/calcium pump. After a muscle impulse, membrane changes and Ca++ diffuse out of cisternae into cytosol. |
| If a muscle impulse causes Ca++ to be released into the cytosol, what does the Ca++ do? | It affects the troponin/tropomyosin which is attached to the actin binding sites. Ca++ bind with the troponin and tropomyosin exposing the binding sites of the actin filaments. This allows binding to occur between myosin cross bridges (hands) and actin. |
| What is the sliding filament model? | It states that during muscle contraction actin and myosin slide past eachother in opposite directions. It shortens space between the z line at the beginning and the z line at the end but the filaments (actin and myosin) never get shorter. |
| What do the thick myosin filaments need to do to prepare for contraction? | they need energy/ATP to get the cross bridges (hands) into a cocked position. |
| What enzyme do myosin cross bridges (hands) contain? | ATPase which catylizes the breakdown of ATP inot ADP and a phosphate group (ADP+P) |
| What does the breakdown of ATP into ADP+P create? | The energy needed for contraction. This is the chemical process that puts the cross bridges (hands) into the cocked position |
| What happens during contraction? | the cocked cross bridges attach to the actin and pull the actin filaments toward the center of the sarcomere. This causes overlap between actin and myosin and shortens the sarcomere (the filaments don't shorten) |
| What is the power stroke? | the action of the cross bridges pulling on the actin |
| What happens after the power stroke? | if more ATP comes along the cycle of breaking it down for energy is repeated and another power stroke occurs. If no more ATP is present, the muscle relaxes. |
| What process drives relaxation to occur? (other than running out of ATP) | The nerve impulse stops releasing ACh. The enzyme acetylcholinesterase breaks down remaining ACh in the synapse. The Ca++ pump (which requires ATP for active transport) moves the Ca++ back into the S.R. ,troponin/tropomyosin covers up actin binding sites |
| Is is faster for a muscle to contract or for a muscle to reset after relaxation? | Contract |
| Muscles use energy in the form of ATP. What two sources do the ATP come from? | 1. creatine phosphate 2. cellular respiration |
| How do muscles use creatine phosphate? | Creatine phosphate stores an extra phosphate group to add to ADP to turn it back into ATP. This energy reserve can only supply a muscle for about 10 seconds. Then muscles have to switch to next fuel source: glucose usually in the form of glycogen. |
| What is cellular respiration? | converting glucose/glycogen into energy. |
| What are the two phases of cellular respiration? | 1. anaerobic phase 2. aerobic phase |
| What are the characteristics of anaerobic phase of respiration? | fast but inefficient. breaks down glucose using glycolysis. produces very little ATP. |
| What are the characteristics of the aerobic phase of respiration? | Slow but efficient. uses citric acid cycle to produce a lot of ATP (34-36 ATP's + heat). Requires oxygen which is stored in the muscles by myoglobin |
| What is myoglobin? | relative of hemoglobin but is stickier and has higher affinity for oxygen. Is storage in muscles for extra oxygen, but not primary source of oxygen. |
| What is oxygen debt? | during strenuous exercise,available oxygen is used for muscle contraction instead of coverting lactic acid to glucose.The oxygen debt must be repaid at a later time.Debt includes the amount of oxygen needed to return blood &tissues to pre-exercise levels |
| What organ converts the lactic acid back to glucose? | liver and it needs oxygen and ATP to do it |
| Why can regular excercise reduce oxygen debt? | The body develops more reserves with frequent exercise. More mitochondria, more capillaries. The capacity for aerobil cellular respiration increases. |
| What are the characteristics of muscle fatigue? | loss of the ability to contract, not enough blood flow to keep up with mitochondria'a oxygen needs, insufficient sodium and potassium ion reserves, build-up of lactic acid which changes pH and prevents muscles from responing to impulses. |
| What is a cramp? | a sustained, painful, involuntary muscle contraction. |
| What is a motor unit? | one motor neuron and all of the muscle fibers controlled by that motor neuron. Could be one muscle fiber or hundreds. (one muscle organ has many motor units. motor units are scattered irregularly so muscle appears to move as one unit. |
| Interesting section on heat production: | heat is a by-product of cellular respiration. Homeostatic mechanisms kick in when exercise produces too much heat (sweating, flushing etc..) |
| What is recruitment? | More motor units get involved in the contraction if they are needed. Not all motor units are involved if they are not needed. Recruitment can increase until all motor units are activated. |
| Why do the number of muscle fibers in a motor unit vary? | muscles can produce more precise movements when they have a lower muscle fiber to motor neuron ratio. |
| What are the characteristics of sustained contractions? | smaller motor units are recruited first (body not sure how many will be needed), larger motor units recruited later, the result is a sustained contraction of increasing strength. |
| What is muscle tone? | even when muscles appear to be at rest, the fibers are in a state of partial contraction. This is important for maintaining good posture. |
| There are many types of contractions, but our class is learning about two. What contractions did we learn in class? | 1. isometric 2. isotonic |
| What are the characteristics of isometric contractions? | all contractions begin with an isometric phase. The muscle remains the same length but tension rises. |
| What are the characteristics of isotonic contractions? | as tension rises, the length of the muscle changes.(The muscle will return to resting length |
| What are the characteristics of fast fibers? | large in diameter, pale in color (white meat), easily fatigued. Can produce rapid, powerful contractions for short duration. Few mitochondria, larger glycogen reserves. |
| What are the characteristics of slow fibers? | slow (take three times longer to contract after stimulation). Smaller in diameter, darker in color due to abundance of myoblobin, fatigue resistant. Also have abundant supply of mitochondria, extensive capillary supply and can contract a long time. |
| How much aerobic exercise is needed to remodel capillary beds? | longer than 2 minutes |
| What is a muscle's origin? | the immovable end |
| What is a muscle's insertion? | the movable end |
| What is a prime mover aka agonist? | muscle primarily responsible for a movement. |
| What does a synergist do? | assist the prime mover |
| What does an antagonist do? | resist the prime mover's action and cause movement in the opposite direction |
| Some muscles are named for origin and insertion. What are the examples discussed in class? | sternocleidomastoid, coracobrachialis |
| What are some terms used to name muscles based on the direction of their fasicles? | rectus (along the axis), oblique, lateral, transverse |
| What are some terms used in muscle naming that describe their actions? | extensor, supinator, abductor |
| What are some terms used in muscle maning that refer to their body region or bone attached to? | brachialis, nasalis, femoral, digitorum |
| What are some terms used in muscle naming that refer to number of origins, size or shape? | biceps, teres, maximus, rhomboideus, orbicularis |
| What is supination? | putting something in a supine position (like hands holding soup) |
| What is pronation? | putting something in the prone position (like palms down) |
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