Chapters 7-9 Flashcards
What are the 4 functions of bones?
-Support & protect softer tissue
-Provide point of attachment for muscles and to facilitate movement
-House blood-producing cells
-Store inorganic salts
What are the five types of bone shapes?
-Long bones
-Short bones
-sesamoid bone
-Flat bones
-Irregular bones
Description and examples of long bones?
Long and narrow such as the femur and humerus
Description and examples of short bones?
Length approximates widths such as the carpals and tarsals
Description and example of semoid bones?
Any round bones that form within tendons adjacent to joint such as the patella
Description and example of flat bones?
Plate-like bones such as the plates of the skull
Description and example of irregular bones?
Variety of shapes such as the vertebral bones
What is the epiphysis?
Expanded end
What is the diaphysis?
Bone shaft
What is the metaphysis?
Intervening portion between epiphysis and diaphysis
What is the articular cartilage?
Covers the ends of bones (epiphysis)
Periosteum?
Dense connective tissue layer that encloses the bone
Compact bone?
The weight-bearing wall of the diaphysis
Where is spongy/cancellous bone located?
Make up the epiphysis
Trabeculae?
Branching bony plates that make up spongy bone
Medullary cavity?
Hollow chamber of shaft (diaphysis) that contains bone marrow
Endosteum?
Lines the interior spaces/cavity of the bone
Bone marrow?
Fills the medullary cavity-includes red and yellow
Bone is made of ____ & ____?
Collagen (connective tissue fiber) & inorganic salts (Calcium)
Mature bones cells are called ____ and occupy chambers called ____?
Osteocytes… Lacunae
Passageways that interconnect lacunae are called ____?
Canaliculi
The structural unit of compact bone is the ____ and is a ____ ____ structure that helps bear ____ and ____ ____?
Osteon… cylindrical structure… weight and resist compression
The matrix of bone is layered in concentric rings called ____ and are centered around a ____ ____ in which blood vessels and nerves pass through?
Lamellae…central canal
Adjacent central canals are joined together vie ____ ____?
Perforating canals
Spongy bone features ____ which is more flexible?
Trabeculae
What are the two ways bone develops?
Intramembranous ossification & Endochondral ossification
Which bones are formed from intramembranous ossification?
Skull bones
What type of bones form from endochondral ossification?
Long bones
What is the 4 step process of intramembranous ossification?
-Mesenchymal cell (embryonic cells) become osteoblasts
-Osteoblasts deposit bone matrix
-Osteoblasts become completely surrounded and transform into osteocytes
-Mesenchyme on outside becomes periosteum
What is the 7 step process of endochondral ossification?
-Hyaline cartilage model
-Chondrocytes enlarge
-Matrix breaks down as chondrocytes die
-Osteoblasts invade the area
-Osteoblasts deposit bone matrix
-Osteoblasts form spongy and then compact bone
-Once encased in lacunae, osteoblasts become osteocytes
What are epiphyseal (growth) plates?
The cartilaginous region where long bones grow in length
What happens when the two ossification centers of a bone meet?
The epiphyseal plate ossifies and the bone can no longer grow in length
Bone can continue to lengthen as ____ ____ of the ____ ___ remain ____?
Cartilage cells… epiphyseal plate… active
What are the four zones of cartilage?
-Resting cartilage
-Proliferating cartilage
-Hypertrophic cartilage
-Calcified cartilage
What is the zone of resting cartilage?
They layer closest to end of epiphysis; resting cells that anchor epiphyseal plate to epiphysis
What is the zone of proliferating cartliage?
Rows of young cells that are actively dividing (mitotically active)
What is the zone of hypertrophic cartilage?
Rows of older cells that help thicken the epiphyseal plate and lengthen the bone; calcifies matrix
What is the zone of calcified cartilage?
Thin layer of dead cartilage cells and calcified matrix
What is the role of osteoblasts?
Replace cartilage with bone tissue
What is the role of osteoclasts?
Break down calcified matrix
Which bone is the last to ossify?
Clavicle
When are all bone ossified?
By the age of 25
What two process maintain bone tissue homeostasis?
Resorption and deposition
What is bone resorption?
Removal of bone; action of osteoclasts
What is bone deposition?
Formation of bone; action of osteoblasts
What are the 3 vitamins critical for bone health?
D, C, & A
What are the three hormones that play a role in bone health?
Growth hormone, Thyroid hormone, & Parathyroid hormone
What is the role of vitamin D in bone health?
Calcium obsorption
What does deficiency of vitamin D cause in children?
Rickets
What does deficiency of vitamin D cause in adults?
Osteomalacia (softening of bones)
What role does vitamin A play in bones?
Affects osteoblast and osteoclast activity
What does deficiency in vitamin A cause in bone?
Retards bone development
What role does vitamin C play in bone formation?
Helps with collagen synthesis
What does deficiency in vitamin C cause in bones?
Slender and fragile bones
What disease can result from vitamin C deficiency?
Scurvy
What does growth hormone (GH) do for bone development?
Stimulates cartilage cell division
Insufficiency in growth hormone causes ____?
Pituitary dwarfism
Excess of growth hormone in children causes ____?
Gigantism
Excess of growth hormone in adults causes ____?
Acromegaly
What two functions does the thyroid hormone have in bone development?
Causes replacement of cartilage with bone in epiphyseal plate and affects osteoblast activity
What does the parathyroid hormone do for bone formation?
Stimulates the breakdown of bone by stimulating osteoclast activity
What are the two general categories of fractures?
Simple/closed fractures and compound/open fractures
What are simple/closed fractures?
Fracture is protected by uninjured skin
What are compound/open fractures?
Fractures in which bone is exposed to the outside through the opening in the skin
What are the six classifications of fractures?
-Greenstick
-Transverse
-Oblique
-Spiral
-fissured
-Comminuted
What is a greenstick fracture?
An incomplete break often seen in children
What is a fissured fracture?
Incomplete longitudinal break
What is comminuted fracture?
Complete; fragments the bone
Transverse fracture?
Complete; occurs at a right angle to the bone shaft
Oblique fracture?
Oblique, occurs at an angle other than a right angle
Spiral fracture?
Caused by excessive twisting; associated with child abuse
What are the 4 phases of fracture repair?
-Hematoma
-Cartilaginous (soft) callus
-Bony callus
-Remodeling
Fracture repair process hematoma?
Large blood clot forms
Fracture repair process cartilaginous (soft) callus?
Phagocytes remove debris and fibrocartilage invades
Fracture repair process bony callus?
Osteoblasts invade and a hard callus fill the space
Fracture repair process remodeling?
Bone restored to close to original shape
What are the 5 major functions of bones?
-Provide shape
-Support body structures
-Protect body structures
-Aids in body movement (bones act as levers which muscles can use to produce motion)
-Contains tissue that produce blood cells
-Stores inorganic salts
Hematopoiesis?
Process by which blood cells are formed
Where does blood cell production occur?
Red bone marrow
What does yellow bone marrow do?
Stores fat
What is the most abundant crystal in bone?
Hydroxyapatite
What is hydroxyapatite?
Calcium (Ca++) and Phospahte (PO4—-)
What does calcitonin do?
Stimulates osteoblasts to deposit Ca++ in the cones which effectively lower blood Ca++ levels
Where is calcitonin released from?
Thyroid gland
What does the parathyroid hormone do?
Causes osteoclasts to breakdown bone to release calcium which effectively raises blood Ca++ levels
What is a fragility fracture a sign of?
Low bone density?
What is a fragility fracture?
A fracture that occurs from less than standing height
What is osteopenia?
Bone loss
What is osteoporosis?
Severe bone loss that leaves canals in bones and weakens them
Who is osteopenia and osteoporosis common in?
Common in post-menopausal women due to hormone changes
What are three ways to prevent osteopenia and osteoporosis?
-30 min exercise/day
-Get enough Ca2+ and Vit. D
-Stop smoking
What are the 5 signs of bones and aging?
a. Height decreases starting at age 30 as bones thin and weaken
b. Osteoclasts outnumber osteoblasts with age
c. Spongy bone weakens before compact bone
d. Bone loss is rapid in menopausal women
e. Hip fractures and vertebral compression fractures become more common
What in another name for joints?
Articulations
What are the three classifications of joints based on structure?
-Fibrous
-Cartilaginous
-Synovial
What is a syndesmosis?
An amphiarthrotic joint either formed by an interosseous membrane or an interosseous ligament such as the tibia-fibular joint
What is a suture?
A connection between flat bones of the skull. Consists of a thin layer of connective tissue (sutural ligament). Synarthrotic
What is a gomphosis?
Cone-shaped process fitting into a socket of jawbone and held with a periodontal ligament. Synarthrotic
What is a synchondrosis?
Composed of bands of hyaline cartilage such as the epiphyseal plate and between manubrium and 1st rib. Synarthrotic
What is a symphysis?
Pad of fibrocartilage between bones with the articular surface being covered with hyaline cartilage such as pubic symphysis and intervertebral discs. Amphiarthrotic
What structure make up a synovial joint?
- articular cartilage
- capsule
a. synovial membrane
b. synovium (fluid)
ii. bursa
iii. meniscus
What are the 6 types of synovial joints?
- ball-and-socket (egs., hips & shoulders)
- condylar (egs., metacarpals & phalanges)
- plane (eg., carpals)
- hinge (eg., elbow)
- pivot (eg., atlantoaxial – C1/C2)
- saddle (eg., carpals/metacarpals of thumb)
Ball-and-socket joint?
-aka spheroidal joint
-features a round head fitting in a cupped cavity
-exhibits widest range of motion
-multiaxial, plus rotation
-egs., hips, shoulders
Condylar joint?
-aka ellipsoidal joint
-oval condyle fits into elliptical cavity
-Back-and-forth; side-to-side motions
-Biaxial movement, but with no rotation
-egs., joints between metacarpals & phalanges
Plane joint?
-aka gliding joint
-almost flat; or, slightly curved
-Back-and-forth; twisting
-nonaxial movement
-eg. wrist & ankle joints
Hinge joint?
-convex surface of one bone sits in concave surface of another bone
-uniaxial movement (in one plane)
-egs., elbows; joints b/w phalanges
Pivot joint?
-aka trochoid joint
cylindrical surface rotates within ring of another bone
-uniaxial movement
-rotation only
-egs., atlas (C1) & dens of axis (C2)
Saddle joint?
-aka sellar joint
-both bones have concave and convex surfaces
-biaxial movement (in two planes)
-egs., carpal & metacarpals of thumb
What is a suture?
-occurs between flat bones of the skull
-consists of thin layer of connective tissue (sutural ligament)
-synarthrotic
What is a gomphosis?
-cone-shaped bony process in a socket in jawbone
-periodontal ligament
-synarthrotic
What are the two types of cartilaginous joints?
i. synchondrosis (eg., costal cartilage)
ii. symphysis (egs., pubic symphysis, intervertebral discs)
What is a synchondrosis?
-composed of bands of hyaline cartilage form joint
-eg, epiphyseal plate (temporary)
-eg., between manubrium & 1st rib
costal cartilage
What is a symphysis?
-pad of fibrocartilage between bones
-articular surfaces covered by hyaline cartilage
amphiarthrotic
-eg., pubic symphysis
-eg., intervertebral discs
What are the three types of joints based on function?
a. Synarthrotic
b. Amphiarthrotic
c. Diarthotic
What are the 4 basic features of skeletal muscle?
a. voluntary
b. promotes movement: attached to bones
c. striated
d. multiple nuclei near periphery of cell
A skeletal muscle is an ____ of the skeletal system?
Organ
What 4 tissues does skeletal muscle consist of?
muscle tissue, nervous tissue, blood & connective tissue
What are the three types of connective tissue in muscle?
i. fascia – dense connective tissue that surrounds the muscle and tapers to form tendons
ii. aponeuroses – broad, fibrous sheet of connective tissue
What are the 3 coverings in a muscle?
-Epimysium
-Perimysium
-Endomysium
What is the epimysium?
surrounds whole muscle
Perimysium?
surrounds fascicles within a muscle
Fascicle?
is a bundle of muscle fibers (cells)
Endomysium?
surrounds muscle fibers within the facsicle
Why is a muscle cell multinucleated?
result of multiple cells fusing together
Sarcolemma?
muscle fiber membrane
Sarcoplasm?
the cytoplasm of the muscle fiber
Myofibrils?
the actin (thin) & myosin (filament) fibers within the muscle cell
Sarcoplasmic reticulum?
specialized endoplasmic reticulum where Ca++ ions are stored
Transverse tubules?
– invaginations of the sarcolemma that extend into the sarcoplasm
Triad?
- triad: 2 cisternae (of SR) + transverse tubule
Sarcomere?
the functional unit of the muscle cell
Z-line?
i. boundaries of the sarcomere
A-band?
represents the thin & thick filaments
H-zone?
thick filaments only – myosin protein
I-band?
thin filaments only (flank the edges of the sarcomere) – actin protein
Thick filaments?
Myosin
Thin filaments?
Actin
What proteins regulate cross-bridging?
- troponin
- tropomyosin
Sliding filament model?
i. contraction occurs as a result of actin (thin) and myosin (thick) filaments sliding past one another
Does the length of filaments change?
No
What is the final result in the sarcomere after contraction?
the H- and I-bands narrow; and, the Z-lines move closer together
Skeletal muscle connects to nervous system via ____ ____?
Neuromuscular junction (NMJ)
Motor neuron?
nervous tissue that relays signal from the central nervous system to the skeletal muscle
Motor end plate?
portion of the skeletal muscle that responds to the motor neuron
Synaptic cleft?
space between the motor neuron & the motor end plate
Synaptic vessicles?
membranous “sacs” found within the terminus of the motor neuron each of which contains neurotransmitter that stimulates a muscle contraction
What is the neurotransmitter for skeletal muscle?
acetylcholine (ACh)
How does a neurotransmitter work?
a. the motor end plate features ACh receptors that bind to the neurotransmitter
b. ACh stimulates a change in membrane potential across the motor end plate
c. Results in the release of Ca++ ions from the SR
What are the 6 steps of the contraction cycle?
-Resting
-ACh stimulates the release of Ca++ ions
-Cross-bridge formation
-Power-stroke
-Cross-bridge release
-Cocking of myosin heads
Contraction cycle: what happens during the resting phase?
Ca++ ions are sequestered in the SR; troponin/tropomyosin is blocking cross-bridge formation
Contraction cycle: what happens during the ACh stimulates the release of Ca++ ions phase?
Ca++ ions from the SR which binds to troponin and facilitates a shift in tropomyosin that reveals myosin-binding sites on actin
Contraction cycle: what happens during the cross-bridge formation phase?
the myosin heads bind to actin
Contraction cycle: what happens during the power-stroke phase?
the release of ADP from myosin causes the filaments to slide
Contraction cycle: what happens during the cross-bridge release?
the myosin-actin association is disrupted when high-energy ATP binds to the myosin head
Contraction cycle: what happens during the cocking of myosin head phase?
the ATP is hydrolyzed to ADP releasing energy which “resets” the myosin heads
3 step process of muscle relaxation?
i. acetylcholinesterase is an enzyme that decomposes the ACh that remains in the synapse
ii. ATP is needed to sequester (pump) Ca++ ions back into the SR
1. Removal of Ca++ results in troponin/tropomyosin to conceal myosin-binding sites on actin again
iii. ATP is also needed to reset (“cock”) myosin heads
What decomposes ACh?
i. acetylcholinesterase
What is ATP?
Adenosine triphosphate
What are the 4 phases of energy used for contraction?
-ATP in the cytoplasm is quickly exhausted during contraction
-Creatine phosphate
-Anaerobic
-Aerobic
Creatine phosphate?
enables muscle cells to regenerate ATP from ADP via phosphate transfer when cellular ATP is low
Where does the anaerobic phase occur?
- occurs in the cytoplasm
Oxygen debt?
the amount of oxygen needed by liver cells to convert lactic acid back to sugars, and to restore muscle ATP & creatine phosphate to original levels
When is the anaerobic phase used?
– limited oxygen availability due to strenuous exertion
What does the anaerobic phase produce?
2 ATP and pyruvic acid which turns into lactic acid
____ ____ ____ + ____ ____ ____ = Aerobic Phase
Citric acid cycle + electron transport chain
Where does the aerobic phase occur?
mitochondria
What does the aerobic phase produce?
34 ATP
What is myoglobin?
an oxygen-binding molecule that helps supply additional oxygen when vascular supplies dwindle
What causes muscle fatigue?
– the inability to contract muscle
1. due to: decreased blood flow; ion imbalance (across sarcolemma); loss of desire to continue to exercise; accumulation of lactic acid
What is a muscle cramp?
sustained, involuntary contraction
What causes a muscle cramp?
changes in electrolyte levels in fluid surrounding muscle cell
Muscle contraction can be measured by ____ ____ ____ ____ ____ of a dissected muscle?
examining changes in muscle length
What is a threshold stimulus?
the minimum strength of stimulus required for contraction
1. produces an action potential resulting in the release of Ca++ ions from the SR of the muscle sample
What is a twitch?
the contractile response to a single impulse
3 periods of a twitch?
a. latent period
b. period of contraction
c. period of relaxation
Optimum starting length is the same as ____ length of a muscle fiber?
Resting
Summation?
the process of combining the force generated by individual muscle fiber twitches
Extremely prolonged contraction called ____ ____ don’t normally occur in humans?
tetanic contractions
What is a motor unit?
(1) the motor neuron + (2) all of the muscle fibers under its control
Coarse movements are produced by?
large # of fibers recruited within a motor unit
Precise movements are produced by?
smaller # of fibers within a motor unit
Recruitment?
the increase in the # of motor units becoming activated which produces additional force
What motor units are recruited 1st during muscle contraction?
- smaller motor units are recruited 1st during sustained contraction
What motor units are recruited 2nd during muscle contraction?
- larger motor units are recruited next during sustained contraction
___ motor units will become activated if a stimulus is significantly long?
All
____ + ____ produce contractions of increasing strength?
Summation + Recruitment
Isotonic?
muscle contracts & changes length
Concentric?
shortening contraction
Eccentric?
lengthening contraction
Isometric?
muscle contracts but does not change length (holding a heavy object stationary)
Slow-twitch muscle fibers?
-aka Type 1
-resistant to fatigue
-slower to contract
-stimulated by aerobic exercise
-high myoglobin
-red coloration
Fast-twitch, fatigue resistant muscle fibers?
-aka Type IIa
-quicker to contract than Type 1
-resistant to fatigue
-stimulated by forceful exercise
-high myoglobin
-red coloration
Fast-twitch, glycolytic fibers?
-aka Type IIb
-contract rapidly
-susceptible to fatigue
-low myoglobin
-white coloration
Two types of smooth muscle?
Multi-unit & Visceral
Multi-unit smooth muscle?
- associated with eye (iris) & walls of blood vessels
- cells are less organized
- each fiber functions independently
Visceral smooth muscle?
- found in walls of hollow organs
- cells function collectively as a unit
- exists as sheets of spindle-shaped muscle fibers
- exhibits rhythmicity
How do smooth muscle fibers appear?
b. fibers are shorter than skeletal muscle, have tapered ends
c. each fiber has a central nucleus
d. not striated
What structures do smooth muscles miss?
d. not striated
e. no transverse tubules; SR not fully developed
What do smooth muscles use in place of troponin?
calmodulin
What do smooth muscles use a a neurotransmitter?
norepinephrine as a neurotransmitter, in addition to ACh
What are cardiac muscles joined by?
intercalated discs
How are cardiac muscles stumulated?
Rhythmic: self-exciting
How do cardiac muscles appear?
Striated and branching
Cardiac muscles features ____ ____ ____ than skeletal muscle?
longer refractory period
