Musculoskeletal system Flashcards
cartilages
is a semi-rigid connective tissue that is found all throughout the body. While cartilage is not as strong as bone, it is much more resilient and flexible.
Chondroblasts,
which are the mature cells that produce the matrix of cartilage.
Chondrocytes
which are the cells encased within the matrix. These cells live in small spaces within the matrix, called lacunae.
skeletal system
consists of the bones, articulations (joints), cartilage, as well as other connective tissues that help to strengthen and stabilize the bones and articulations.
Cartilage has 3 main functions in the body:
- provides support to the soft tissue
- Provides a protective covering at articulating surfaces.
- Serve as a model for bone growth
There are 3 types [text annotation indicator] of cartilage found in the body:
- hyaline cartilage
- fibro-cartilage
- Elastic Cartilage
Hyaline Cartilage
most common and weakest form in the body
Provides support through resiliency & flexibility
Functions to help support soft tissue, form the fetal skeleton, and serves as a model for most future bone growth
Location: articulations (joints), nose, trachea, larynx, costal cartilage (where the ribs attach to the sternum)
Fibrocartilage
Extremely durable
Functions to act as a shock absorber & help the body resist compressive forces
Location: intervertebral discs, pubic symphysis, menisci
Elastic Cartilage
Contains numerous elastic fibers within its matrix, ensuring resiliency & flexibility
Location: epiglottis (structure in the throat), external ear
Function of the Bone
Support & Protection - Bones serve as a framework of support for the entire body.
Movement - Bones serve as the attachment site for muscles, soft tissue, and some organs.
Hemopoiesis - The process of producing new blood cells is called hemopoiesis
Storage - Approximately 90% of the calcium and phosphate in the body is stored and released by the bones.
long bone
Bones that have a greater length than width
Have a long, cylindrical shaft
Most common
Predominantly found in the upper & lower limbs (femur, humerus, tibia, ulna,
short bone
Bones that have nearly equal length and width.
External surface covers = compact bone; internal = spony bone
Found in the wrist (carpals) and foot (tarsals)
flat bone
Bones that have a flat, think surface.
Provide lots of surface area for muscle & soft tissue attachment
Found in many bones that form the roof of the skull, scapula (shoulder blades), and ribs
irregular bone
Bones with elaborate, complex shapes that don’t fit any of the other classes.
Examples include the vertebra, os coxae (hip bones), and some bones in the skull
Sesamoid Bones
Bones that embedded within a tendon
Found in the knee (patella) and on the bottom side of the foot
diaphysis
of a long bone is its long, cylindrical shaft. The diaphysis plays an important role in help provide leverage and structural support.
The diaphysis of the bone contains the following structures
Medullary Cavity
Endosteum
Periosteum
Epiphysis
of a long bone are its expanded, knobby regions located on the ends of the bone. The epiphysis helps to strengthen to joint by increasing the surface area for bone-to-bone contact and functions as an attachment site for many tendons and ligaments.
Metaphysis
of a long bone is the region of the bone that lies between the diaphysis and epiphysis. In a growing bone, this is the region of the bone that contains the epiphyseal plates, or growth plates.
Osteoprogenitors
Stem cells found within the endosteum and periosteum. These cells help produce more stem cells that later mature to become osteoblasts.
Osteoblasts
: Cells that produce new bone.
Osteocytes
Mature bone cells that reside within the lacunae (small spaces within the matrix). These cells help maintain the bone matrix by detecting any sort of mechanical stress on a bone.
Osteoclasts
These are large, multinucleate, phagocytic cells are involved with a process known as bone resorption (dissolves bone).
a long bone contains 4 major sets of blood vessels:
Nutrient blood vessels The nutrient artery and vein are responsible for supplying the diaphysis of the bone.
Metaphyseal blood vessels The metaphyseal arteries and veins are responsible for supplying blood between the diaphysis and epiphysis.
Eiphyseal blood vessels: The epiphyseal arteries and veins are responsible for supplying blood to the epiphysis and epiphyseal plate.
Periosteal blood vessels The periosteal arteries and veins are responsible for supplying blood to the periosteum of the bone.
During aging, our bones change in two ways:
- We lose the ability to produce organic matrix due to a reduction in the osteoctye activity. This, in turn, results in a failure of the osteoblasts to produce enough new bone growth to maintain the matrix. (a.k.a osteocytes stop telling osteoblasts to build bone)
- We lose calcium and other bone salts.
osteoporosis
The changes in bone that occur during aging can result in a decrease in an individual’s bone density
how many bones does the adult body have
206
axial skeleton
forms the main framework that supports and protects the organs. A total of 80 bones form the axial skeleton, including the skull, vertebral column, and thoracic cage.
appendicular skeleton
is made up of 126 bones (63 per side) and includes the bones of the upper and lower limbs, along with the girdles that help attach the upper and lower limbs to the axial skeleton.
articulation
or joint, is the location of contact between: 1) bones, 2) bones and cartilage, or 3) bones and teeth. Articulations can vary in both stability and mobility, depending on the structure of the joint.
Synarthroses
Immobile joint
Most stable
Example: sutures of the skull
Amphiarthroses
Slightly mobile join
Examples: intervertebral, tibiofibular
Diarthroses
Freely mobile joint
Examples: knee, elbow, shoulder, hip, many more…
Fibrous joints
use dense regular connective tissue to hold bones together. Most fibrous joints are immobile or only slightly mobile.
3 type of Fibrous Joints
Gomphoses
Suture
syndesmoses
Gomphoses
are only found where the roots of the teeth articulate with the sockets in the maxilla and mandible.
Think “peg in a socket”
The teeth are held together by a fibrous peridontal membrane
Sutures
are immobile fibrous joints found between some bones of the skull
Contain distinct, interlocking, usually irregular edges that help increase strength and decrease fractures
Permit the skull to grow as the brain increases in size during childhood
Sutures completely fuse together in adulthood
Syndesmoses
are fibrous joints found between parallel long bones (radius & ulna, tibia & fibula).
Allow for slight movement (amphiarthroses)
Shafts of the parallel bones are bound side-by-side by a broad, ligamentous sheet called an interosseous membrane, which provides a pivot point where the bones can move against one another.
Medullary Cavity
The hollow, cylindrical space within the diaphysis.
Endosteum
A thin layer of cells that lines the inner surface of the medullary cavity. It covers most internal surfaces of the bone and contains osteoblasts and osteoclasts
Periosteum
Long bones are surrounded in a tough, sleeve-like layer of dense, fibrous connective tissue. Periosteum covers all external surfaces of the bone, except the areas that are covered by articular cartilage
Cartilagenous joints
use cartilage to attach bones together. Like fibrous joints, cartilaginous joints lack a joint cavity
2 types of cartilgenous joints
synchondroses
symphyses
Synchondroses
are cartilaginous joints held together by hyaline cartilage. Immobile joints (synarthroses)
Found in the epiphyseal plates of children (helps bind the epiphysis & diaphysis of long bones)
Also located in the costochondral joints (between the ribs and the costal cartilage)
Symphyses
are cartilaginous joints held together by a pad of fibrocartilage. All permit slight movement (amphiarthroses)
Shock absorber for joints - help resist compression
Pubic symphysis, located between the right and left pubic bones
Intervertebral joints, located between the bodies of the vertebrae
Synovial joints
are separated by a space, referred to as the joint cavity. (shoulder, elbow, knee, ankle, wrist,
Tendons
attach muscle to bone
joint cavity
that contains snyovial fluid, helping to separate the articulating bones
Synovial fluid
which is secreted by the inner layer of the articular capsule (synovial membrane)
Lubricates the articular cartilage
Noureshes the articular cartilage
Acts as a shock absorber
Bursa
Fibrous sac-like structure that contains synovial fluid
Designed to eleviate friction from various body movements
Fat pads
are the “packing material” of the joint, serving to providing protection
Sensory nerves and blood vessels
innervate and supply blood to the articular capsule and associated ligaments
Nerves signal pain, amount of motion, & stretch in the joint
Vessels nourish the tissues within the joint
Uniaxial
bone moves in only one plane or axis
Biaxial
bone moves in two planes or axis
Multiaxial
bone moves in more than two planes or axis
Plane (gliding) joint:
Simplest synovial articulation Least mobile Uniaxial Flat, or planar, articulating surfaces Examples: intercarpal, intertarsal
Hinge joint:
Uniaxial
Convext surface of one bone articulates with concave depression of another bone
Think “hinge on a door”
Examples: tibiofemoral, interphalangeal
Pivot joint:
Uniaxial
Rounded surface on one bone articulates with a ring formed by a ligament and another bone
Bone rotates around a longitudinal axis
Examples: radioulnar, atlantoaxial
Condylar (ellipsoid) joint:
Biaxial
Oval, convex surface on one bone articulates with a concave articular surface on another
Examples: metacarpophalangeal, radiocarpal
Saddle joint:
Biaxial, but allows for greater movement than a condylar joint
Articular surfaces have convex and concave regions
Resembles the shape of a saddle
Examples: I carpometacarpal
Ball-and-socket joint
Multiaxial
Most freely mobile synovial joint
Spherical articulating surface of one bone articulates with a rounded, cup-like socket on another bone
Examples: glenohumeral, iliofemoral
Excitability
Level of responsiveness
Outside stimuli have the ability to initiate electrical changes within the muscle fiber (cell), leading to contraction of the muscle fiber
Contractility
When a muscle fiber is stimulated, it generates tension (contraction) within the cell that can lead to shortening of the muscle fiber
Shortening then pulls on bones, resulting in movement
Elasticity
Cell’s ability to return to its original length
Contracted muscle cells will recoil back to their resting lengthen once the applied tension is removed
Extensibility
Capable of extending in length, in response to the contraction of opposing muscles
Example: when the biceps contract to flex the elbow, the triceps must stretch
Cardiac muscle fibers are found almost exclusively within the heart wall. These fibers posses the following characteristics:
Striated
Posses only 1 or 2 nuclei
Form Y shaped branches
Join adjacent muscle fibers to form junctions called intercalated discs
Contraction results in movement of blood
Under involuntary control
authorhythmic
Cardiac muscle tissues are capable of generating an impulse without the nervous system.
Smooth muscle fibers are found within the walls of the viscera (organs of the abdominopelvic cavity). These fibers posses the following characteristics:
No striations
Posses a single, centrally located nucleus
Relatively short, spindle-shaped cells (wide in the middle, tapered on ends)
Contraction results in movement of food and blood
Under involuntary control
Body Movement
Skeletal muscles attach to bone through tendons
Skeletal muscle contracts, causing tendons to pull on bones, resulting in movement
Maintenance of Posture
Contraction of some skeletal muscles helps to stabilize joints & maintain posture
Postural muscles are continuously contracting (when awake) to maintain upright postion
Temperature Regulation
Muscle contraction requires energy & head is a byproduct of energy
Helps maintain our normal body temperature
Think about exercise - when you work out, you physically feel warmer!
Think about when you’re cold! Your muscles contract & relax (shivering) in an attempt to produce heat
Storage & Movement of Materials
Sphincters (circular muscles) contract at body openings to control the flow and passage of materails
Support
Skeletal muscles can be aligned in flat sheets/layers
Sheets help protect organs & support their weight
Think about your abdominal muscles that help hold the abdominal organs in place
Skeletal muscles are made up of numerous skeletal muscle fibers. As such, we organize skeletal muscles as follows from superficial to deep:
Each muscle is comprised of multiple fascicles
Muscle fibers are organized into bundles, called fasciles
Muscle fibers contain myofibrils
Myofibrils are made up of myofilaments
Myofilaments are mainly composed of actin and myosin
endomysium
is the innermost layer that surrounds and electrically insulates each muscle fiber
perimysium
is the middle layer that surrounds each of the fasciles.
epimysium
is the most superficial layer that surrounding the entire skeletal muscle
deep fascia
helps to separate individual muscles, bind together muscles with common functions, and forms sheaths to help distribute blood vessels and nerves to the tissues.
superficial fascia
is located external to the deep fascia and helps to separate the muscle from the skin.
At the ends of each muscle, all of the connective tissue merge together to form a
tendon
The less mobile attachment of the muscle is termed the
origin.
The more mobile attachment of the muscle is termed the
insertion
Isometric Contractions
Length: does not change
Speed: does not change
Resistance: can change
Results in NO movement
Tension produced by the muscle does not exceed the resistance (load)
Example: trying to lift an extremely heavy object, pushing against a wall
Isotonic Contractions
Length: changes Speed: changes Resistance: remains the same Results in MOVEMENT Tension produced by the muscle is equal or greater than the resistance (load) Example: bicep curl, squats 2 types of isotonic contractions:
A contraction is said to be concentric when the muscle actively shortens. A contraction is said to be eccentric when the muscle lengthens
Circular Muscles
Fibers are concentrically aligned around an opening or recess
Circular muscles are also called sphincters
Located at the entrances & exits of internal passageways
Example: orbicularis oris (opening of the mouth)
Parallel Muscles
Fascicles run parallel the long axis of the muscle
Muscle shortens when contracted, and its body increases in diameter
Have high endurance, but not as strong as other types of muscles
Example: rectus abdominis (forms the “six-pack”)
Convergent Muscles
Widespread muscle fibers that converge into a common attachment site
Often triangular in shape & resemble a broad fan
Versatile muscle - direction of pull can change by activating a single group of fibers
Example: pectoralis major (chest muscle)
Pennate Muscles
Tendons and muscle fibers resemble a large feather
One or more tendons extending through their body, with fasciles arranged at an oblique angle to the tendon
3 types of Pennate Muscles
Bipennate
Unipennate
Multipennate
All muscle fibers on the same side of the tendon
Example: extensor digitorum (extends the fingers)
Unipennate
Muscle fibers on both sides of the tendon
Example: rectus femoris
Bipennate
Branches of tendon within the muscle
Example: deltoid
Multipennate
is the wasting away of tissue that results in a reduction of muscle size, tone, and power.
Muscle atrophy
is an increase in the size of muscle fibers
Muscle hypertrophy
Agonist
a.k.a prime mover
Contraction produces a specific movement
Example: triceps brachii (posterior arm) is agonist in extension of the elbow
Antagonist
Muscle whose action opposes the agonist
If agonist produces extension, antagonish will produce flexion (and visa versa)
Example: biceps brachii would be an antagonist to the triceps brachii
Synergist
Muscle who assists the action of the agonist
Typically more useful at the start of movements
Example: biceps brachii and brachialis muscles of the arm are synergists, both working together to flex the elbow
Muscle Action
Name indicates the primary function or movement of the muscle
i.e. flexor, extensor, pronator
Examples: flexor digitorum longus, pronator quadratus, etc.
Specific body regions
Name indicates the region of the body where the muscle is located
i.e. superficialis, externus, anterior, profundus
Examples: tibialis anterior, flexor digitorum profundus, rectus femoris
Muscle attachments
Name indicates the muscle’s origins, insertions, or other prominent attachment points
Examples: sternocleidomastoid, intercostals, subscapularis
Orientation of muscle fibers
Name indicates the direction or orientation in which the muscle fibers align
i.e. rectus, oblique, orbicularis
Examples: rectus abdominis, external oblique
Muscle shape and size
Name indicates the general shape or size of a muscle
i.e. magnus, teres, deltoid, trapezius, longus, magnus, etc.
Examples: gluteus minimus, adductor longus, pectoralis minor, etc.
Muscle heads/tendons of origin
Name indicates specific features like how many tendons of origin, the number of muscle bellies, or number of heads the muscle contains
i.e. bi, tri, quad, etc.
Examples: biceps brachii, quadriceps femoris, triceps brachii
