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Anatomy Unit 3

Terms in this set (71)

Axial Skeleton
The skull, vertebral column, ribs, and sternum
Appendicular Skeleton
Bones of the limbs and limb girdles that are attached to the axial skeleton
Skeletal System
System of protection and support composed primarily of bone and cartilage
Compact Bone
Also called cortical bone, dense bone in which the bony matrix is solidly filled with organic ground substance and inorganic salts, leaving only tiny spaces (lacunae) that contain the osteocytes, or bone cells.
Compact bone makes up 80 percent of the human skeleton
Spongy Bone
Also known as cancellous bone or trabecular bone, is a very porous type of bone and is highly vascularized and contains red bone marrow. Spongy bone is usually located at the ends of the long bones, with the harder compact bone surrounding it.
Also found inside the vertebrae, in the ribs, in the skull and in the bones of the joints.
Spongy bone is softer and weaker than compact bone, but is also more flexible.
Characterized by a lattice-like matrix network called trabeculae that gives it its spongy appearance.
Long Bones
Function to support the weight of the body and facilitate movement.
Long bones are mostly located in the appendicular skeleton and include bones in the lower limbs (the tibia, fibula, femur, metatarsals, and phalanges) and bones in the upper limbs (the humerus, radius, ulna, metacarpals, and phalanges).
Short Bones
About as long as they are wide.
Located in the wrist and ankle joints, short bones provide stability and some movement.
Flat Bones
Function is to protect internal organs such as the brain, heart, and pelvic organs.
Flat bones are somewhat flattened and can provide protection, like a shield
Can also provide large areas of attachment for muscles.
Irregular Bones
Vary in shape and structure and therefore do not fit into any other category (flat, short, long, or sesamoid)
They often have a fairly complex shape, which helps protect internal organ
The vertebrae, irregular bones of the vertebral column, protect the spinal cord.
Diaphysis
elongated shaft of a long bone.
Periosteum
double-layered connective tissue membrane that covers and nourishes the bone.
Epiphysis
the end of a long bone.
Articular Cartilage
Articular cartilage is the smooth, white tissue that covers the ends of bones where they come together to form joints
Allows the bones to glide over each other with very little friction
Epiphysis Line/Plate
Plate of hyaline cartilage found in children and adolescents, located in the metaphysis at the ends of each long bone
In adults, epiphyseal plate is replaced with the epiphyseal line and marks the point of union were the epiphysis meets the diaphysis
Permits growth and lengthening of the bone, as the cartilage reproduces and ossifies
Synarthroses
An immovable joint
Amphiarthroses
A joint that has limited mobility
Diarthroses
A freely mobile joint is classified as a diarthrosis
Ligament
A cord of fibrous tissue that connects bones.
Tendon
Cord of dense fibrous tissue attaching a muscle to a bone
Osteocyte
A mature bone cell
Fontanels
The fibrous membranes in the skull where bone has not yet formed, space between the bones of the skull in babies
Myofilament
Filaments composing the myofibrils
Of two types: actin and myosin.
Myosin
One of the principal contractile proteins found in muscle.
Actin
A contractile protein.
Epimysium
The sheath of fibrous connective tissue surrounding a muscle
Endomysium
The thin connective tissue surrounding each muscle cell
Perimysium
The connective tissue enveloping bundles of muscle fibers
Voluntary Muscle
Muscle under control of the will; skeletal muscle.
Sarcomere
The smallest contractile unit of muscle; extends from one Z disc to the next.
Atrophy
A reduction in size or wasting away of an organ or cell resulting from disease or lack of use
Flaccid
Soft; flabby; relaxed
Isometric (Contractions)
Of the same length.
Isotonic (Contractions)
Having a uniform tension; of the same tone.
Muscular Dystrophy
A progressive disorder marked by atrophy and stiffness of the muscles.
Acetylcholine
A chemical transmitter substance released by certain nerve endings.
Action Potential
An electrical event occurring when a stimulus of sufficient intensity is applied to a neuron or muscle cell, allowing sodium ions to move into the cell and reverse the polarity.
Nueromuscular Junction
the region where a motor neuron comes into close contact with a skeletal muscle cell.
Nuerotransmitter
chemical released by neurons that may, upon binding to receptors of neurons or effector cells, stimulate or inhibit them.
Muscle Fibers
muscle cells.
Muscle Tone
sustained partial contraction of a muscle in response to stretch receptor inputs; keeps the muscle healthy and ready to react.
Muscle Twitch
a single rapid contraction of a muscle followed by relaxation.
Origin
attachment of a muscle that remains relatively fixed during muscular contraction.
Insertion
the movable attachment of a muscle as opposed to its origin.
Flexion
bending; the movement that decreases the angle between bones.
Extension
movement that increases the angle of a joint, e.g., straightening a flexed knee.
Hyperextension
excessive joint movement in which the angle formed by the bones of a particular joint is opened, or straightened, beyond its normal, healthy, range of motion
Rotation
to turn about an axis. (Wrists)
Abduction
to move away from the midline of the body.
Adduction
movement of a body part toward the body's mid-line.
Circumduction
circular movement of a body part.
Supination
the outward rotation of the forearm causing palms to face anteriorly.
Pronation
the inward rotation of the forearm causing the radius to cross diagonally over the ulnaâ€"palms face posteriorly.
Origin
attachment of a muscle that remains relatively fixed during muscular contraction.
Insertion
the movable attachment of a muscle as opposed to its origin.
Flexion
bending; the movement that decreases the angle between bones.
Extension
movement that increases the angle of a joint, e.g., straightening a flexed knee.
Ossification
The process of creating bone, that is of transforming cartilage (or fibrous tissue) into bone.
Hematopoiesis
The production of all types of blood cells including formation, development, and differentiation of blood cells.
Prime Mover
Muscle whose contractions are primarily responsible for a particular movement; agonist.
Antagonist
Muscles that act in opposition to an agonist or prime mover.
Synergist
Muscles cooperating with another muscle or muscle group to produce a desired movement.
Fixator
Muscles acting to immobilize a joint or a bone; fixes the origin of a muscle so that muscle action can be exerted at the insertion.
Rectus
Each of a pair of long flat muscles at the front of the abdomen, joining the sternum to the pubis and acting to bend the whole body forward or sideways.
Oblique
A muscle neither parallel nor perpendicular to the long axis of a body or limb.
Maximus
The greatest gluteal muscle and the biggest muscle in the human body.
Minimus
The innermost of the three muscles in each buttock that arises from the outer surface of the ilium, that is inserted into the greater trochanter of the femur, and that acts similarly to the gluteus medius.
Longus
A long, slender, superficial fusiform muscle of the forearm, lying on the medial side of the flexor carpi radialis that functions to flex the hand.
Deltoid
A large, triangular muscle covering the joint of the shoulder, the action of which raises the arm away from the side of the body.
Flexor
A muscle whose contraction bends a limb or other part of the body.
any of a number of specific muscles in the arm, hand, leg, or foot.
Extensor
A muscle whose contraction extends or straightens a limb or other part of the body.
Adductor
Muscles of the legs pull the legs toward the midline of the body so the legs are closer together.
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