Epidermis
a. outermost layer of skin
b. keratinized stratified squamous epithelium
c. protect underlying layers and prevents fluid loss
d. avascular
Dermis
a. underlying connective tissue layer of skin - composed of collagen
b. extremely tough and pliable due elastin fibers
c. highly vascular
Langer Lines
a. Tension lines in dermis; collagen runs in parallel bundles; keeps skin under constant tension
b. During surgery cut parallel to these lines, otherwise wounds gape open (and makes healing harder)
Arrector pili
a smooth muscle attached to hair follicles that causes "goose bumps" to appear on the skin when contracted
Skin Ligaments
a. numerous small fibrous bands, extend through the subcutaneous tissue and attach the deep surface of the dermis to the underlying deep fascia
b. vary in density and length in different regions
Fascia
a. band or sheet of fibrous connective tissue that covers, supports, and separates structures
b. can be thick and tough (to hold structures in place) or can be loose, pliable, and filled with fat tissue (to protect/insulate a structure or internal organ)
Superficial Fascia
a. Layer deep to the dermis that has varying levels of fat
b. allows for skin movement
c. site for blood vessels, lymphatic vessels, and nerves going to and from skin
Deep Fascia
a. relatively thick layer of dense connective tissue over the surface of several muscles in a body region
b. in the limbs, this surrounds all muscles of the limb
c. often has thick extensions that connect to underlying bone periosteum and separates groups
Investing Fascia
thinner extensions of the deep fascia that surround individual muscles and blood vessels/nerves and allow movement of muscles over adjacent structures
General Somatic Afferent
carry sensory info from the skin or muscles to the spinal cord
General Somatic Efferent
carry motor info to skeletal muscle from the spinal cord
General Visceral Afferent
carry sensory info from body organs, blood vessels, and glands to the spinal cord
General Visceral Efferent
carry motor info to body organs, blood vessels, and glands from the spinal cord
Ventral Roots
Ventral roots can be found on each side the spinal cord - they are formed from the convergence of ventral rootlets that have come from the ventral side of the spinal cord
Can refer to the roots based on the spinal cord level they originate from
All axons
Dorsal Roots
Dorsal roots carry the sensory info from spinal nerves towards the spinal cord
The dorsal root ganglion is an enlargement located near the spinal nerve that contains all the cell bodies for the sensory axons
These roots carry GSA and GVA axons (these axon
Spinal Nerves
The ventral and dorsal roots converge together in the intervertebral foramen where they form a spinal nerve which will then emerge from the intervertebral foramen
They are relatively short - will quickly diverge in the ventral and dorsal rami
These nerves
Ventral Rami
Ventral rami are terminal branches of the spinal nerves that project to the body (excluding the back)
Thoracic and Upper lumbar - will stay relatively segmented as branches project to the skeletal muscle and skin
In other levels, the ventral rami will mix
Dorsal Rami
Dorsal rami are terminal branches of the spinal nerves that project to deep back muscles (will innervate the back in segments)
Down to T6 - medial branches form cutaneous nerves
T7 to T12 - lateral branches form cutaneous nerves
Gluteal region - includes
Long Bones
longer than they are wide
ex: humerus, femur, metacarpal bones
Short Bones
Roughly cuboidal in shape
ex: the ankle and wrist bones.
Flat Bones
These bones are thin, flat, and curved.
ex: scapula, sternum, and calvaria (skull)
Irregular Bones
various shaped bones not fitting into other categories
Ex: vertebrae
Sesamoid Bones
seed shaped bones that are embedded in tendons
ex: patella
Diaphysis
main, central part of the bone
Epiphysis
ends of the bones; proximal and distal
Metaphysis
area of junction between the diaphysis and each epiphysis
epiphyseal line is here - where the epiphyseal plate (growth plate) was in the growing plate
Medullary Cavity
Interior portion of the diapyhsis that contains bone marrow
Periosteum
Connective tissue covering the external bone surface except at the ends of the bone that are covered in articular cartilage
Endosteum
connective tissue lining the medullary cavity
Nutrient Foramen
Narrow tunnel through the diaphysis that allows blood vessels (nutrient artery and vein) into the medullary cavity
Hyaline Cartilage
Most common type of cartilage
Found on the articular surfaces of most bones (articular cartilage)
Forms costal cartilages and tracheal rings
Elastic Cartilage
Helps to form the epiglottis and the external ear
Fibrocartilage
present in the intervertebral discs (between adjacent vertebrae), pubic symphysis (between the two pubic bones of the pelvis), and in articular discs found within some joints
Fibrous Joints
surfaces are joined together by dense connective tissue and have no intervening joint cavity
Sutures (joints)
found only between bones of the skull - contain minimal amount of fibrous tissue between bones
Syndesmosis (joints)
occurs where two bones are connected by a sheet of dense connective tissue
present where the interosseus membrane links the radius and ulna in upper limb and the tibia and fibula in lower limb
Gomphosis (joints)
only example is the tooth being linked by the periodontal ligament collagen fibers to the bony socket
Cartilaginous Joints
surfaces are joined together by cartilaginous tissue and have no intervening joint cavity
Synchondrosisi Joints
surfaces are joined by hyaline cartilage. These are present in the epiphyseal (growth) plates of developing bones and in the costochondral junction between the ribs and the costal cartilages
Symphysis Joints
surfaces are joined by fibrocartilage. The intervertebral discs between vertebrae and the pubic symphysis of the pelvis are examples
Synovial Joint
contains a fluid-filled joint cavity which allows for increased mobility between the articulating surfaces. All synovial joints are examples of diarthroses since they are freely movable
Components of Synovial Joints
a. articular cartilage - usually composed of hyaline cartilage.
b. joint (synovial) cavity - the space between articulating surfaces.
c. articular capsule - composed of an outer fibrous capsule continuous with the periosteum of the surrounding bones and a
Articular Disc
fibrocartilaginous structures within the joint cavity that help to absorb compressive forces and make the contours of the opposing surfaces more congruent - examples are found in the knee and sternoclavicular joints
Bursa
a closed sac filled with synovial fluid present at sites where friction develops between bones and tendons, ligaments, or skin - some develop regular connections with joint cavities
Classification of Synovial Joint based on movement (3 types)
a. uniaxial joint - movement only in one plane.
b. biaxial joint - movement in two planes.
c. multiaxial joint - movement in more than two planes.
Plane Joint
articulating surfaces are flat - allows gliding or sliding movements
examples are the acromioclavicular joint, and joints between articular processes of vertebra and intercarpal and intertarsal joint
Hinge Joint
cylindrical end of one bone fits into a trough shaped end of articulating bone - allows uniaxial movement
example is humeroulnar joint (at elbow)
Pivot Joint
rounded end of one bone fits into a ring of bone plus fibrous tissue in another bone - allows rotary movement
examples are atlantoaxial joint (between C1 and C2 vertebrae) and proximal radioulnar joint (at elbow).
Condyloid (ellipsoid) Joint
egg-shaped surface of one bone fits into a concavity on the other bone - biaxial movement allowed
example is the metacarpophalangeal (knuckle) joint
Saddle Joint
saddle-shaped articular surfaces with concave and convex surfaces on each bone - biaxial movements
example is the first carpometacarpal joint
Ball and Socket Joint
the spherical end of one bone fits into the concave socket of the adjoining bone - multiaxial movements
examples are the glenohumeral (shoulder) and femoroacetabular (hip) joints
Hilton's Law
States that a joint is innervated by branches from the nerves that innervate the muscles that move/cross the joint.
These articular nerves are important in transmitting pain and proprioceptive ("position in space") information, and for innervating the sur
Tendon
strong, orderly dense connective tissue cord that attaches a muscle to bone
Tendon Sheath
enclosed serous membrane lined "cavity" filled with synovial fluid, similar to a bursa, but it surrounds a tendon as it passes underneath retinacula or through other fibrous structure (ie. fibrous digital sheath) to decrease friction
Origin
the most proximal attachment site of a muscle that usually remains fixed in position during muscle contraction
Insertion
the more distal muscle attachment site that usually moves the most during muscle contraction
Aponeurosis
wide, flattened tendinous sheet that forms the attaching structure for some muscles
Raphe
a seam, or line of union, between symmetrical parts (terms used in places other than just with some muscles
Shapes of Muscles
a. flat (eg. external abdominal oblique).
b. pennate - means "feather-like" due to muscle fibers inserting on intramuscular tendon elements.
1. unipennate - muscle fibers approach a tendon from one direction (e.g. extensor digitorum longus).
2. bipennate
Isometric Contraction
the muscle tension increases, but the muscle length remains the same - occurs when a muscle is resisting forces of gravity or forces from antagonistic muscles
Isotonic Contraction
the muscle changes length in association with a movement
Concentric Contraction
the most commonly thought of type of muscle contraction - the muscle shortens during contraction that produces a movement
Eccentric Contraction
the muscle lengthens while it is contracting since an apposing muscle or force is generating a greater force
Prime Mover (agonist)
the main muscle that produces the specific movement - typically by concentric contraction
Antagonist
a muscle that opposes the specific movement of the prime mover by eccentric contraction that is progressively relaxed to allow smooth movements to occur
Fixator
a muscle that contracts isometrically to stabilize the proximal part of the limb so that the agonist can function efficiently
Synergist
may act similar to the prime mover, but from a more disadvantaged position and thus be weaker. Synergists may also be muscles that stabilize other joints that the prime mover crosses, thus allowing the prime mover's action to be concentrated on the desire
Spurt Action
the primary force of muscle contraction is passing across the moving bone, causing the point of muscle insertion to move in an arc towards the fixed bone - occurs in muscles whose fixed attachment site is further away from the moving joint than is the att
Shunt Action
the primary force of muscle contraction acts along the moving bone and pulls the two articulating bones closer together - occurs in muscles whose fixed attachment site if nearer to the joint than is the attachment site on the bone that is moving
Lymph
is a fluid that consists of recovered interstitial fluid, cellular debris, pathogens, and lymphocytes
Lymph Vessels
Blind-ended lymph capillaries merge into larger and larger lymph vessels, well supplied with valves to facilitate one-way flow of lymph, back towards the systemic circulation.
The lymph vessels from the small intestine also contain chyle which includes th
Lymph Nodes
Encapsulated masses of lymphoid tissue found along the course of the lymph vessels that function to remove particulate matter from the lymph and to react to foreign antigens.
The location of lymph nodes is relatively constant and they drain specific struc
Multipolar Neuron
most common type of neuron - contains one long axon transmitting information away from the neuron cell body (soma) and two or more dendrites relaying information to the neuron cell body.
Motor neurons to skeletal muscle and viscera are multipolar
Pseudounipolar Neuron
Have what appears to be a single process with a connecting stem to the cell body - actually contains a peripheral process (bringing information toward the cell body from the periphery) and a central process (transmitting information from the cell body, to
Ganglion
Collection of neuron cell bodies located outside the CNA
Nucleus (nervous system)
Collection of neuron cell bodies located within the CNS
Nerve Fiber
an axon and its myelin sheath
Nerve
Bundle of nerve fibers outside the CNS that has connective tissue coverings and blood vessels supplying these tissues
Synapse
Site of communication between neurons where information is transferred between cells
Motor Unit
Single motor neuron and all of the muscle fibers it innervates