Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
92 Cards in this Set
- Front
- Back
|
Skeletal System Functions
|
-Supprt
-Protection -Movement -Storage -Blood cell production within bone marrow |
|
|
Support Function
|
-bones- major supporting
tissues in the body -cartilage- provides firm yet flexible support -ligaments- attach bones and hold them together |
|
|
Protection Function
|
-the skull protects the brain
-vertebrae protects the spinal cord -rib cage protects the chest organs |
|
|
Storage
|
-Ca2+ need for blood clotting and heart functioning (electrical signaling)
-Phosphorus for ATP and DNA synthesis |
|
|
Cartilage
|
-Consists of cells called chondrocytes
-Perichondrium is a double -layer connective tissue sheet that covers cartilage. -Cartilage Growth -appositional growth -Interstitial Growth |
|
|
Chondrocytes
|
-chrondroblasts secrete new cartilage matrix
-when the chondroblast surrounds itself with secreted matrix it matures into a chondrocytes |
|
|
Perichondrium
|
-outer layer is made of dense regular connective tissue with fibroblasts
-inner layer is made mostly with chrondroblasts |
|
|
Appositional Growth
|
-growth from the outside
-Chrondroblasts lay down new matrix against outside of tissue |
|
|
Interstitial Growth
|
-growth from the inside
-inner chondrocytes rapidly divide expanding cartilage from within |
|
|
General Bone characteristics
|
-206 named bones
-each bone is an organ -made of living tissue that grows and repairs -axial skeleton -Appendicular Skeleton -4 bone shapes |
|
|
axial skeleton
|
-function: protection and support
-includes:skull, vertebrae column, rib cage |
|
|
Appendicular Skeleton
|
-function: movement
-includes:upper and lower limbs, shoulder and pelvic girdles |
|
|
4 bone shapes
|
-long bones
-short bones -flat bones -irregular bones |
|
|
long bones
|
-longer than wide
-most bones of upper and lower limbs ( humerus and fibia) |
|
|
short bones
|
-as wide as long
-ex. most bones of wrist and ankle |
|
|
flat bones
|
-thin, flat, usually curved
-ex. some skull bones, ribs, sternum, and scapula |
|
|
irregular bones
|
-odd shaped
-vertebrate, patella (sesamoid bone) |
|
|
Long Bone Structure
|
-Diaphysis
-Epiphysis -Epiphyseal Plate -Medullary Cavity -Periosteum -Endosteum |
|
|
Diaphysis
|
-Shaft that forms the long axis
-Composed of compact bone |
|
|
Epiphysis
|
-knobs at the end of long bones
-composed mostly of spongy/cancellous bone -outer covering is compact bone |
|
|
Epiphyseal Plate
|
-hyaline cartilage
-area of growth -at the end of the growth period gets completely transformed into bone is called the epiphyseal line. |
|
|
Medullary Cavity
|
-in diaphysis at long bone
-in children contains red bone marrow -in adults red bone marrow is replaced by yellow marrow |
|
|
Periosteum
|
-Connective Tissue membrane covering outer surface of bone
-2 layers -outermost=dense irregular connective tissue with blood vessels and nerves -innermost= 2 cells types -osteoblasts-bone forming cells -osteoclasts- bone resorbing cells -sharpie’s fibers-secure tendons and ligaments to bone |
|
|
Endosteum
|
-a connective tissue membrane lining the inner bone surfaces
|
|
|
Flat Bone
|
-Usually have no epiphysis or diaphysis
-Spongy bone in flat bone is called diploe between layers of compact bone |
|
|
Short and Irregular
|
-spongy bone center
-compact bone on outer surface |
|
|
Microscopic Anatomy of Compact Bone
|
-Organized structural units called osteons
|
|
|
Osteon
|
-lamellae- circular layers of bone matrix
-lamellae surround a common center called the haversian canal -passage way for blood vessels and nerves at junctions of lamellae are small cavities called lacuna -called osteocytes -small canals called canaliculi connect the lamellae to each other and to Haversian Canal -waste and nutrient exchange in a blood vessel for osteocytes |
|
|
Bone Development
|
-Process is called osteogenesis or ossification
-Begins 8 weeks after conception -At birth, most long bones are well ossified except at the epiphyseal plate -Bones of skull do not even begin to ossify until 10th week after conception |
|
|
epiphyseal plate
|
-complete ossification occurs at end of growth period (then called epiphyseal line)
|
|
|
Ossification
|
-not completely ossified at birth, connected by fibrous membranes called fontanels
-allow head to compress during birth -accommodate rapid brain growth and development -final ossification=2 years of age |
|
|
Growth in bone length
|
-new bone is formed on the surface of cartilage (or old bone)
-occurs at epiphyseal plate |
|
|
epiphyseal plate
|
plate is organized into 4 zones
-Zone of resting cartilage -Zone of Proliferation -Zone of hypertrophy -Zone of calcification |
|
|
Zone of resting cartilage
|
-nearest the epiphysis
-contains randomly arranged chondrocytes that are slowly dividing |
|
|
Zone of Proliferation
|
-chondrocytes are producing new cartilage through interstitial growth with rapid dividing
|
|
|
Zone of hypertrophy
|
-chondrocytes produced in zone 2 mature and enlarge
|
|
|
Zone of calcification
|
-consists of cartilage matrix mineralized with Ca2+
-hypertrophized chondrocytes die; blood vessels innervate area -CT surrounding blood vessles contains osteoblasts, they deposit new bone matrix on top of the cartilage (appositional growth) |
|
|
Factors Afecting Bone Growth
|
Nutrition
Hormones |
|
|
Nutrition affecting bone growth
|
-Vitamin D
-Vitamin C |
|
|
Vitamin D
|
-Needed for absorption of Ca2+ in small intestines
-Deficiency in children called Rickets, a disease caused by reduced mineralization of the bone matrix (bones “bow”) -adults with inability to metabolize Vitamin D. can develop osteomalacia, softening of bones as a result of Ca2+ depletion |
|
|
Vitamin C
|
-Necessary for collagen synthesis by osteoblasts
-Deficiency can result in scurvy, a disease characterized by ulceration and hemorrhage of skin (due to lack of normal collagen in CT) |
|
|
Hormones Affecting Bone Growth
|
-2 hormones regulate the exchange of Ca2+ between the blood and bone
-Calcitonin -Parathyroid Hormone |
|
|
Calcitonin
|
-Synthesized by the thyroid gland
-promotes the incorporation of Ca2+ from blood to bone -Sensitive to circulating estrogen levels -high estrogen= high calcitonin in release, Ca2+ incorporation into bone -low estrogen= low calcitonin release, low Ca2+ incorporation in bone -menopause for women may develop osteoporosis, due to decrease in Ca2+ deposits in bone |
|
|
Parathyroid Hormone
|
-Synthesized by parathyroid gland
-Signal for release is low plasma Ca2+ levels -Mobilizes Ca2+ stores from bone into blood |
|
|
Classes of Joints
|
-Fibrous Joints
-Cartilaginous Tissue -Synovial Joints |
|
|
Fibrous Joints
|
-2 bones united by fibrous CT
-Exhibit very little to no movement -Classified in 3 groups based on structure -Sutures -Syndesmoses -Gamphoses |
|
|
Sutures
|
-seams between skull bones
-very stable, opposite bones have “interlocking processes” -ex. coronal suture- between frontal and parietal bones -ex. lambdoidal suture- between occipital and parietal bones |
|
|
Syndesmoses
|
-Fibrous joint that joins bones via ligaments
-ligaments are flexible so some movement can occur -ex. tibiofibular- joint between tibia and fibular |
|
|
Gamphoses
|
-Specialized joints consisting of “pegs and sockets”
-held in place by bundles of fibrous CT called periodontal ligaments -only example between, teeth and mandible/maxilla |
|
|
Cartilaginous Tissue
|
-2 bones united by hyaline or fibro-cartilage
-Classified in 2 groups -Synchondroses -Symphyses |
|
|
Synchondroses
|
-2 bones joined by hyaline cartilage
-little to no movement -ex. epiphyseal plate between epiphysis and diaphysis of growing bone -ex. between costal cartilage of 1st rib and mandible |
|
|
Symphyses
|
-2 bones united by fibro-cartilage
-flexible, some movement is allowed -ex. pubic synthesis -ex. intervertebral disks |
|
|
Synovial Joints
|
-articulating bones are seperated by a fluid filled cavity
-Fluid is synovial fluid -Includes most joints of the body ( ALL joints of the articulating limbs) -highly movable |
|
|
General Characteristics of ALL Muscles
|
-Classified as “excitable tissue”
-Contraction involves the shortening of tissue -Relaxation involves lengthening/ stretching of the tissue back to its original length -Muscle tissue makes up about 40% of total body mass |
|
|
excitable tissue
|
only contracts in response to electrical activity on the surface of the muscle cell membrane
|
|
|
General Functions of Muscle Tissue
|
-Body movement (skeletal)
-Maintenance of posture (skeletal) -Constriction of organs and vessels (smooth). -Rhythmic beating of the heart (cardiac) -Production of heat as a bi-product of contraction (ALL) |
|
|
Connective Tissue
|
-Epimysium
-Dense CT layer around whole muscle -also called fascia -Perimysium -within each skeletal muscle the fibers are called fascicle -covers each fascicles -Endomysium -reticular CT that covers each fiber in the fascicles |
|
|
Neural Innervation
|
-Motor neuron- specialized nerve cells
-some are in spinal cord and axons extend to muscle fibers -function: electrically stimulate muscles to contract -the contract between fibers is called the neuromusclular junction (NMJ) -each motor neuron innervates several muscle fibers -a motor neuron and all the muscle fibers it innervates is a motor unit |
|
|
General Characteristics of Microscopic Anatomy
|
-Each fiber is a long cylindrical cell with multiple oval nuclei
-Plasma membrane- sarcolemma -Intracellular fluid- sarcoplasma -Each muscle fiber is made of many myofibril -Each myofibril is made of 2 types of myofilaments -actin (thin filaments) -myosin (thick filaments) -Actin and myosin are organized in structural units called sarcomeres |
|
|
Sarcoplasma
|
-contains glycosomas which store glycogen for energy
-contains myoglobin which is a red-pigmented O2 storing protein |
|
|
myofibrils
|
-thread like structures that extend from one end of fiber to the other
|
|
|
Actin
|
-2 strands of fibrous- actin (F-actin)
-coiled to form a double helix -each f-actin strand is made of ~ 200 small globular units called G-actin -each G-unit has an “active site” to which myosin molecules bind during contraction |
|
|
Tropomyosin
|
-stabelizes a protein that winds along a groove in the F-actin strand
|
|
|
Troponin
|
-3 polypeptide complex
-Tn-I binds to G-actin -TN-T binds to tropomyosin anchoring it to the F-actin strand -Tn-C binds to C2+ |
|
|
Myosin
|
9-each filament has a rod like tail consisting of 2 intertwined poly-peptide chains
-each filament also has 2 heads that have 3 components each -bonding site for actin -binding site for ATP -has ATPase activity splits ATP to yield energy needed for contraction -junction of head and tail is the hinge region -allows head to bend and straighten during contraction |
|
|
Sarcomere
|
-each sarcomere extends from one z-disk to the next z-disk
-protein attachment site for actin z-disk -Striations seen microscopically due to alternating light and dark bands -A- bands- dark bands consisting of both actin and myosin -I bands- light bands containing actin only -H- zone- band in the middle of the A band contains only myosin -M-line- line in the middle of the H-zone that holds the myosin in place |
|
|
T-tubules (Transverse Tubules)
|
-Invagination of muscle cell sarcolemma
-Runs between lateral sacs forming a TRIAD -T-Tubule -Lateral Sacs -Functions to quickly transmit electricity (action potential) throughout the muscle cell -electricity stimulates the release of Ca2+ from lateral sacs |
|
|
Sarcoplasmic reticulum
|
-Surrounds each myofibril
-Upon electrical stimulation releases Ca2+ from specific storage areas called lateral sacs |
|
|
Function of Ca2+
|
-Ca2+ released from lateral sacs due to the action potential diffuses in the sarcomere
-the calcium bonds to TnC of troponin -Conformational change the occurs in the actin, such that troponin and tropomyosin shift and expose the binding site for myosin (when muscle is relaxed, the binding site is covered up by Tn and Tropomyosin) -myosin heads are able to alternately bind and detach from the actin -The hinge region of the myosin pulls the actin filaments toward the center of the sarcomere -The shortening of the sarcomere via actin and myosin attachment and detachment will continue as long as Ca2+ is in the sarcomere -For relaxation to take place, Ca2+ must be removed from the sarcomere |
|
|
Sliding Filament Theory
|
1. thin filaments (actin) slide toward center of sarcomere
2. distance between z disks is reduced 3.I band shortens 4. H zone disappears 5. A bands move closer together 6. *Actin and Myosin bands do not change in length |
|
|
Relaxation
|
-Located on the surface of the sarcoplasmic reticulum is a Ca2+ ATPase pump
-Using energy gained from the splitting sarcomere and back into the lateral sacs -troponin and tropomyosin recover myosin binding site -actin and myosin can no longer attach and relaxation occurs -sarcomere returns to original length |
|
|
Function of ATP
|
-Contraction
-Powers the ratcheting movement of myosin head -After each ratcheting movement a new ATP molecule binds to the myosin head so it can detach then bind to a distant G-actin -Relaxation -Powers the pump that removes calcium from the sarcomere |
|
|
Action Potential
|
-An Action Potential is the reversal of the resting membrane potential, such that the inside of the cell becomes more positive than the outside
-at resting membrane potential the inside is more negative, POLARIZED -Permeability changes are due to the opening of protein ion channels winthin membrane (2) layers -Chemical Gate Ion Channels -Voltage Gate Ion Channels -The ion will move into or out of the cell depending on its concentration gradient ( always DOWN) -In nerve and skeletal tissue an excitatory stimulus (chemically or voltage/electrical) will cause Na+ channels to open -Na+ will move down its gradient in the cell (Na+ influx) -Na+ brings the positive charge with it, creating intracellular positivity -This phase of a action potential is called DEPOLARIZATION -When the Na+ channels close, Na+ influx stops -At about same time Na+ close, voltage gated K+ channels to open -K+ will move down its gradient out of the cell (K+ efflux) -K+ takes its positive charge with it, creating intracellular negativity -this phase of the action potential is called REPOLARIZATION -At the end of re-polarization K+ channels don’t immediately close and excess K+ leaves the cell -the membrane temporarily becomes more negative at rest HYPERPOLARIZATION |
|
|
Due to changes in membrane permeability
|
-At resting membrane potential it is more permeable to K+ than to Na+
-To generate an action potential the membrane becomes more permeable to Na+ - To end the action potential the membrane becomes more permeable to K+ again |
|
|
Chemical Gate Ion Channels
|
-open or close when a chemically binds to a protein receptor that is part of the ion channel
-ex. Acetylcholine (Ach) is a neurotransmitter that cause Na+ channels on skeletal muscle to open |
|
|
Voltage Gated Ion Channels
|
-open or close in response to voltage changes across the membrane (more negative or more positive)
|
|
|
Patchclimbing
|
-Cells at resting membrane potential, then it receives an excitatory stimulus (*)
-Voltage range that opens some Na+ channels, allowing for Na+ influx and cell interior gradually becomes more positive/less negative -THRESHOLD- voltage tat allows many Na+ channels to open, allowing lots of Na+ influx creates a steep incline (spike potential) of positivity -Voltage at which Na+ channels close and K+ channel open up allowing for K+ efflux, ICF becomes, more negative/ less positive -excess K+ efflux -Na+/K+ pump begins to actively pull some K+ back into the cell until resting membrane potential is restored |
|
|
Look at Excitation Concentration Coupling notes along with handout please
|
Look at Excitation Concentration Coupling notes along with handout please
|
|
|
Muscle Mechanics
|
-Normal form curve
-Recording of a single muscle twitch/ contraction using a myogram -3 Periods -Latency -Contraction -Relaxation |
|
|
Latency
|
-indicates all events that occur from initial action potential production in motor neuron up to and including the attachment of actin and myosin
|
|
|
Contraction
|
-repeated attachment, ratcheting, and detachment of myosin head
-sliding filament theory mechanism, shortening of sarcomere |
|
|
Relaxation
|
-Ca2+ is actively pumped from the sarcomere
-Actin and myosin detach and don’t reattach until the next stimulus -Sarcomere regains its original length |
|
|
Muscle Metabolism
|
-Continuous muscle contraction requires a continuous source of ATP
-Skeletal Muscle fiber types based on metabolic characteristics -Slow oxidative fibers -Fast Glycolytic Fibers -Fast Oxidative Fibers |
|
|
3 Pathways for aTP
|
-Direct Phosphorylation of ADP by Creatine Phosphate (CP)
-Anaerobic Respirations/ Glycolysis -Aerobic Respiration/ Oxidative Phosphorylation |
|
|
Direct Phosphorylation of ADP by Creatine Phosphate (CP)
|
-CP is a high energy molecule that’s stored in muscle
-1st source of energy -Rxn: CP + ADP yields Creatine and ATP -CK = Creatine Kinase -Yield is 1 ATP molecule per 1 CP molecule -15 seconds of activity |
|
|
Anaerobic Respirations/ Glycolysis
|
-does not require oxygen
-involves the catabolism of glycolysis obtained from blood or from the breakdown of glycogen stores in muscle (within glycosomas) -the glucose is broken into ATP and pyruvic acid -Yields 2 ATP molecules per Glucose molecule -30-60 seconds of activity |
|
|
Aerobic Respiration/ Oxidative Phosphorylation
|
-requires oxygen
-pyruvic acid is taken from glycolysis and is transfered to Krebs Cycle -within mitochondria high energy bonds are broken and ATP is released -Yields 34 ATP molecules per glucose molecule (pyruvic acid gained from glucose catabolism) -plus the original 2 from glycolysis -hours of activity |
|
|
-Slow oxidative fibers
|
-Myosin ATPase works slow, slow speed of contraction
-Uses oxidative phosphorylation for ATP production -Red in color due to high myoglobin stores -Oxygen storage -Relatively fatigue resistant and have high endurance -uses= long distance running and posture |
|
|
Fast Glycolytic Fibers
|
-Myosin ATPase works fast, fast speed of contraction
-Uses glycolysis to generate ATP -White in color -no need for oxygen, no need for myoglobin -Very susceptible to fatigue because of limited glycogen stores -uses= short term intense movement lifting a large load |
|
|
Fast Oxidative Fibers
|
-Intermediate between Slow Oxidative and Fast Glycolytic
-Fast speed of contraction -Uses Oxidative Phosphorylation and Glycolysis for ATP production -Have myoglobin and Glycogen stores -Pink in color -Moderately fatigue resistant -Uses=walking - |
|
|
-Myasthenia Gravis
|
-auto immune disease
-body destroys its own Ach receptors on skeletal muscle -Not all Ach molecules are able to bind to a functioning receptor to stimulate contraction -More Ach is destroyed by Ach estase than is used to contribute to muscle function -Often treated with Neostigmine |
|
|
Neostigmine
|
-Ach esterase blocker
-allows Ach to stay in the neuromuscular junction longer, increasing the stimulation of functioning receptors. |
