Musculoskeletal Physiology Flashcards
Bones contain organic components such as
collagen and various mineral elements, including 98% of calcium storage in the body
Bone has vascular structures, can heal itself and is dynamic and changing
Low bone mass density can lead to osteopenia (pre disease state) and if untreated, can progress to osteoporosis
Osteoporosis
bone disease which causes skeletal structures to become brittle and fragile, often leading to fractures and disability
Skeleton consists of two segments:
Axial skeleton - skull, hyoid bone, vertebral column, and rib cage
Appendicular skeleton - the limbs and their respective girdles
Epiphyseal plate:
transverse cartilage plates located near the end of long bones are responsible for increases in vertical growth during childhood/adolescence
Bone length increases until the cartilage is ossified in the epiphyseal plates of long bones; peak bone mass is usually attained by about age 18
Bone types
Long bones (arms/legs)
Short bones (hands/feet)
Irregular bones (vertebrae)
Flat bones (scapula)
Body mass density (BMD) can be improved until what age?
30
genetics, behaviors and lifestyle factors dictate the rate of decline – muscle strength is a key indicator
the intersection of two bones; major types include fibrous, cartilaginous and synovial
Joint
Synovial joint:
uses synovial fluid to reduce frictional stresses and allow for considerable movement between the associated articulating bones
Joints of the appendicular skeleton are mostly synovial to support locomotion and activity needs
Synovial joints include: plane, pivot, hinge, condyloid, saddle, ball & socket.
Synovial joints
PLANE JOINT
A plane joint allows bones to slide past each other.
Midcarpal and midtarsal joints are plane joints.
PIVOT JOINT
A pivot joint allows
rotator arouna am axis,
Pivot joints are found in the neck and forearm.
HINGE JOINT
A hinge joint allows extension and retraction of an appendage. Hinge joints are found in the knees, elbows, fingers, and toes.
CONDYLOID JOINT
A condyloid joint is similar to a ball and socket but with less movement. Ex. Wrist
A saddle joint allows
to ball and socket but with movement back and forth less movement. The wrist and up and down. The is a condyloid joint.
SADDLE JOINT
A saddle joint allows
to ball and socket but with movement back and forth less movement. The wrist and up and down. The is a condyloid joint.
only saddle joint in the human body is the thumb.
BALL-AND-SOCKET JOINT
A ball and socket joint allows for radical movement in almost any direction. Ball-and-socket joints are found in the shoulders and hips.
Ligament
: fibrous bands of connective tissue that support internal organs and hold bones together at joints
Tendons
: fibrous band of connective tissue that connects muscles to bones
Ligaments and tendons assist in providing structural support to strengthen joints
Three types of muscles
Skeletal, cardiac, smooth
Muscle Fascia
: fibrous connective tissue that encapsulates full muscles as well as bundles of fibers; provides the muscle’s shape and regulates tension/transfer of force across joints
How muscles contract
Nerve information is carried via action potentials
Action potential: wave-like electrical change in a cell membrane that signals the cascade of events leading to a muscular contraction
Action potential current travels to motor neurons which connect to specific fibers (motor unit)
Motor unit: motor neuron and all the muscle fibers it innervates
Sliding Filament Theory:
An action potential travels down T-tubules to stimulate the sarcoplasmic reticulum to release calcium ions which unlock the bond between actin filaments and troponin
When troponin is moved due to calcium activity, myosin can attach to actin forming a cross bridge via its myosin head
ATP is split at the myosin-actin attachment site which releases energy and allows the myosin head to pull or “slide” the actin to shorten/contract the muscle fiber
