MSK Functional Anatomy Flashcards
What are the 3 types of muscle tissue?
Skeletal, cardiac, smooth
Describe skeletal muscle
- attached to bones
- conscious control
- somatic nervous control
- striated
- multinucleated
Describe cardiac muscle
- wall of heart
- not under conscious control
- autonomic nervous control
- striated
- uninucleated
Describe smooth muscle
- walls of most viscera, blood vessels, skin
- not under conscious control
- autonomic
- not striated
- uninucleated
Define origin and insertion
origin - immovable end of muscle attachment
insertion - movable end of muscle attachment
Define prime mover (agonist)
the muscle primarily responsible for movement
define synergist
assists prime mover muscle
define antagonist
muscle that resists the prime mover’s action and causes movement in the opposite direction
What are the 7 shapes of muscles
- circular (orbicularis oris)
- convergent (pec major)
- parallel (sartorius)
- unipennate (EDL)
- bipennate (rectus femoris)
- fusiform (biceps brachii)
- multipennate (deltoid)
Name and define the 3 types of connective tissue coverings
- epimysium: dense regular connective tissue surrounding entire muscle
- perimysium: fibrous connective tissue surrounding fascicles
- endomysium: fine areolar connective tissue surrounding each muscle fiber
Characteristics of a muscle cell
cylindrical, 30cm long, multiple peripheral nuclei, many mitochondria, myoglobin for O2 storage, contains myofibrils, sarcoplasmic reticulum, T tubules
Characteristics of a myofibril
- densely packed rod like element
- 80% of cell volume
- exhibit striations through perfectly aligned repeating dark anistropic bands and light isotropic bands
Characteristics of a sarcomere
- smallest contractile unit
- region of a myofibril between two Z disks
- composed of thick and thin myofilaments made of contractile proteins
characteristics of the sarcoplasmic retigulum
- network of smooth endoplasmic reticulum surrounding each myofibril
- pairs of terminal cisternae forming perpendicular channels
- stores most of the Ca2+
Characteristics of T tubules
- invagination of sarcolemma into sarcoplasm - extracellular compartment
- penetrate cell’s interior at each A band-I band junction
Describe the triad relation
nerve impulse stimulates release of ACh which binds to receptors on motor plate of neuron generating an impulse which reaches the T tubule and depolarizes it, releasing Ca2+ leading to muscle contraction
repolarization of T tubule causes calcium channels in the cisternae to close and stop contraction
Describe the neuromuscular junction
The site where an axon and muscle fiber meet, consisting of:
- motor neuron
- motor end plate
- synapse
- synaptic cleft
- synaptic vesicles
- neurotransmitters
Describe myasthenia gravis
Muscle paralysis
-inability of the NMJ to transmit enough signals from nerve to muscle fibers
-Abs attack ACh receptors
Describe the steps of a muscle contraction
- Nerve impulse cases release of ACh from synaptic vesicles
- ACh binds to receptors on motor end plate
- muscle impulse generated
- impulse reaches the sarcoplasmic reticulum and cisternae
Describe the steps of excitation-contraction coupling
- muscle impulse causes SR to release CA2+ into cytosol
- Ca2+ binds to troponin to change its shape
- tropomyosin position is altered
- binding sites on actin are now exposed
- actin and myosin molecules bind via myosin cross-bridges
Describe the steps of cross-bridge cycling
- myosin cross bridge attaches to actin binding site
- myosin cross-bridge pulls thin filament
- ADP and phosphate released from myosin
- new ATP binds to myosin
- linkage between actin and myosin cross-bridge breaks
- ATP splits
- myosin cross-bridge goes back to original position
Name and describe the 2 types of muscle contraction
-Isotonic: generates force by changing muscle length (eccentric = lengthening, concentric = shortening)
-Isometric: muscle contracts but without significant change in length
Describe white skeletal muscle
- large, powerful fibers
- poor blood supply
- high capacity for anaerobic glycolysis
- susceptible to fatigue
- ex: leg and ocular muscles
Describe red skeletal muscle
- small, less powerful fibers with more myoglobin
- good blood supply
- high capacity for aerobic glycolysis
- resistant to fatigue
- ex: posture muscles
Describe the characteristics of cartilage
- specialized type of connective tissue
- does not have vessels or nerves
- surrounded by perichondrium
- fetal precursor tissue to bone
- supports non-skeletal structures
Name and describe the 3 types of cartilage
-Hyaline: provides support, flexibility, resilience. most abundant type, can become calcified
- elastic: similar to hyaline but more elastic
- fibrocartilage: more collagen, great tensile strength
Name the typical locations of hyaline cartilage
intercostals
wall of trachea and bronchii
articular cartilage of bone
epiphyseal plates
fetal axial skeleton
name the typical locations of fibrocartilage
intervertebral discs
pubic symphysis
meniscus of knee
attach tendon to bone
name the typical locations of elastic cartilage
external ear
walls of external auditory canal and eustachian tubes
epiglottis and larynx
bridge of nose
Describe interstitial growth of cartilage
chondroblasts in existing cartilage divide and form cells that produce matrix, occurs in immature cartilage
describe appositional growth of cartilage
mesenchymal cells in deep part of perichondrium differentiate into chondroblasts, occurs in mature cartilage
Describe compact bone
dense and usually limited to the cortices of mature bone
describe cancellous bone
lattice of bone spicules, occurs in the ends of long bones and fills the flat and irregular bones
classifications of bones
long, short (sesamoid, cube), flat, irregular
Name the parts of a long bone
Name the membranes of a bone
- periosteum: outer fibrous layer with an inner osteogenic layer, contains osteoblasts/clasts/genic cells, nerves and vessels
- endosteum: delicate membrane on internal surfaces of bone containing osteoblasts/clasts
Where is hematopietic tissue located
red marrow cavities (Trabecular cavities of long bone head of femur/humerus and in diploe of flat bones)
Name the blood supply of a long bone
diaphysial, metaphysial, and epiphysial arteries
Describe the nerve supply of bones
-autonomic and sensory supply
- most numerous in the articular extremities
Describe the bone matrix
-ground substance in which collagen fibers are embedded
-10-20% = water
-60-70% = mineral salts
Name and define the 4 types of bone cells
-osteogenic cell: stem cell in periosteum and endosteum that makes osteoblasts
-osteoblast: bone forming cell
-osteocyte: mature bone cell
-osteoclast: breaks down/resorbs bone matrix
Describe the structural unit of compact bone (Osteon/Haversian System)
-lamellae: weight bearing, column-like matrix
- central canal: contains blood vessels and nerves
Name the structures that make up the microstructure of a compact bone
- Perforating/Volkmann’s canals
- Lacunae
- Canaliculi
Name the structures that make up the microstructure of spongy bone
-trabeculae that align along lines of stress, capillaries in endosteum supply nutrients, irregularly arranged lamellae, osteocytes, and canaliculi
Name and describe the two types of ossification
-Intramembranous: membrane bone develops from fibrous membrane and fomes flat bones
-endochondral: cartilage bone forms by replacing hyaline cartilage forming the majority of the skeleton
Describe interstitial and appositional bone growth
-interstitial: lengthening of long bones
-appositional: thickening and remodeling of all bones by osteoblast/clast activity
Name the 4 functional zones of epiphyseal plate cartilage
-Proliferation (growth)
-Hypertrophic (cells enlarge)
-Calcification
-Ossification
What controls continual remodeling of bone?
Hormonal mechanisms that maintain calcium homeostasis in the blood
Describe Wolff’s Law
A bone grows or remodels in response to forces or demands placed on it
(handedness thickens bone in dominant hand, thickness of curved bones where they may buckle, trabeculae along stress lines, large bony projections at site of muscle attachment)
Name the 4 steps of bone healing
Describe what happens in Osteomalacia and Rickets
calcium salts are not deposited, typically caused by a deficiency of vitamin D and/or dietary calcium
Rickets is a childhood disease that causes bowed legs and other bone deformities
Describe what happens in osteoporosis
a loss of bone mass because bone resorption outpaces deposit, leading to bone becoming spongy and susceptible to fracture
risk factors include: low estrogen, vit D, Ca, TSH, immobility, petite frame, DM
Describe the 3 classes of joints
- synarthrosis = immovable
- amphiarthrosis = slightly movable
- diarthrosis = freely movable
What are the 3 types of synarthrotic joints
- sutures (skull)
- syndesmoses (fibula/tibia)
- gomphoses (teeth)
Name the 2 types of cartilaginous joints
-Synchondronses: bar/plate of hyaline cartilage uniting a bone (synarthrotic)
-Symphyses: hyaline cartilage covers articulating surfaces and is fused to pad of fibrocartilage (amphiarthrotic)
Name the 7 types of synovial joints
plane
hinge
pivot
bicondylar
ellipsoid
saddle
ball and socket
