Musculoskeletal System Flashcards
What does red bone marrow form?
blood cells e.g. RBCs, platelets, WBCs
What is yellow bone marrow?
stored energy in the form of fat
What are the 2 canals in the bone matrix?
- vertical Haversian canals
- horizontal Volkmann’s canals
What is seen in a cross-section of a bone?
concentric arrangements of osteocytes with Haversian canals in the centre to form osteons
How are osteons produced?
through the continuous process of bone remodelling
What are the 3 types of bone cell and what do they do?
- osteocytes - transfer calcium to the ECF without destroying the bone structure
- osteoclasts - secrete hydrochloric acid that dissolves calcium phosphate crystals and enzymes that break down the organic matrix
- osteoblasts - secrete organic matrix (osteoid) within which calcium phosphate crystals precipitate
What does a typical joint have?
hyaline (glass-like) articular surfaces made of cartilage
What is synovial fluid secreted by?
synovial membrane lining the joint cavity from inside
What is the joint capsule?
the outer fibrous protective layer of a joint
What are the 2 main joint types?
- ball and socket - can move around 3 axes e.g. shoulder and hip joint
- hinge - can only move in one axis e.g. elbow and knee joint
What is a tendon?
a fibrous structure that connects a muscle to a bone
What is the epimysium?
the outermost protective connective tissue layer within which there are multiple fascicles that contain muscle cells
What is each fascicle in the epimysium lined by?
another connective layer called the perimysium
What does each muscle fibre consist of?
multiple myofibrils
What are muscle fibres?
striated, long, cylindrical multinucleated cells that undergo voluntary, rapid and powerful contractions
What is the fundamental contractile unit of muscle?
a sarcomere
What are the 2 major myofilaments in a sarcomere?
- myosin (thick)
- actin (thin)
What is one sarcomere length made up of?
a set of overlapping myosin and actin myofilaments bound by two Z discs
What is the sliding filament theory?
muscle contraction occurs when thick and thin filaments slide past each other which shortens the sarcomere
What is the origin of the muscle?
the proximal attachment point that doesn’t move during contraction
What is the insertion of the muscle?
the distal attachment point that moves when the muscle contracts
What is the pectoralis and what is it involved in?
a thick, fan-shaped muscle present anteriorly in the chest area involved in flexion and adduction of the arm at the shoulder joint
What are the biceps brachii and what are they involved in?
muscle present anteriorly in the upper arm involved in flexion of the forearm at the elbow joint
What are the triceps and what are they involved in?
muscle present posteriorly in the upper arm involved in extension of the forearm at the elbow joint
What is the deltoid muscle and what is it involved in?
muscle that covers the shoulder joint involved in flexion, extension and abduction of the arm at the shoulder joint
What is the trapezius and what is it involved in?
a large triangular muscle present in the upper back region involved in stabilising posture
What is the latissimus dorsi muscle and what is it involved in?
a muscle present in the middle and lower back region involved in the extension and adduction of the arm at the shoulder joint
Where is the rectus abdominis?
anteriorly in the abdomen region
What are the quadriceps femoris and what are they involved in?
a group of 4 muscles present anteriorly in the thigh involved in flexion of the thigh at the hip joint and extension of the leg at the knee joint
Where does the common tendon of the quadriceps insert into?
patella bone (kneecap)
What is the hamstring and what is it involved in?
a group of 3 muscles present posteriorly in the thigh involved in extension of the thigh at the hip joint and flexion of the leg at the knee joint
What are the 3 muscles of the hamstring?
- semimembranosus – flat and broad, present most medially
- semitendinosus
- biceps femoris – present most laterally
What is the gastrocnemius muscle and what is it involved in?
the bulk of most of the calf muscle present posteriorly in the lower leg essential for movement and stability involved in flexion of the leg at the knee joint
What is the soleus muscle and what is it essential for?
part of the calf muscle group present posteriorly in the lower leg (deeper than gastrocnemius) essential for standing and walking
What is the gluteus maximus and what is it involved in?
the largest muscle present posteriorly in the hip region involved in extension of the thigh at the hip joint
Why do bones become weaker with age?
bone density decreases
What are common causes of paralysis?
strokes, spinal cord injuries and nerve disorders
