Wk 3 Vocab Flashcards
A band
Large, dark bands in a skeletal muscle fiber that alternate with lighter I bands to give a striped appearance to skeletal muscle fibers under a microscope. Composed of thick filaments of the contractile protein myosin.
Abductor muscle
A muscle that moves away from the median plane
Actin filament
A protein that forms microfilaments. It is fond in the cytoskeleton, in myofibrils of muscle fibers, and in spindle fibers during cell division.
Adductor muscle
A muscle that moves toward the median plane
Adenosine diphosphate
The discharged form of ATP. A nucleotide that contains 2 phosphoric acid groups.
Adenosine triphosphate
A hight-energy molecule produced in the mitochondria of cells. it is a nucleotide that contains three phosphoric acid groups. When a phosphate group is split from an ATP molecule to produce ADP, energy is released that powers the sliding of the actin and myosin filaments in muscle over each other.
Aerobic metabolism
Oxygen consuming metabolism. More efficient
Agonist
Prime mover - directly produces a desired movement
Anaerobic metabolism
Non-oxygen dependent metabolism.
Antagonist
directly opposes the action of an agonist
Aponeurosis
A broad sheet of fibrous connective tissue that attaches certain muscles to bones or to other muscles.
Brachium
The upper arm. The area of the thoracic limb between the elbow and the shoulder.
Creatine phosphate
(CP) The molecule in muscle cells that splits to release the energy necessary to reattach the detached phosphate group to an adenosine diphosphate (ADP) molecute to convert it back to the high-energy molecule adenosine triphosphate (ATP).
Cutaneous muscle
“Skin muscles”; thin muscles in the connective tissue beneath the skin. When a cutaneous muscle contracts, it causes the skin to twitch.
Diaphragm
The thin, dome-shaped sheet of muscle that forms the boundary between the thoracic and abdominal cavities.
Endomysium
The thin, delicate layer of connective tissue that surrounds each individual skeletal muscle fiber.
Epimysium
The tough connective tissue layer that covers and delineates individual muscles. It surrounds groups of skeletal muscle fascicles.
Expiratory muscle
A muscle whose action is to decrease the size of the thoracic cavity; this squeezes air out of the lungs, thereby producing expiration (exhalation).
Fascicle
A group of skeletal muscle fibers bound together by a layer of fibrous connective tissue called the perimysiym
Fixator
A muscle that stabilizes a joint so that other muscles can produce effective movements of other joints
H band
various visible bands on fillaments
I band
Large, light bands in a skeletal muscle fiber that alternate with the darker A bands to give a striped appearance to skeletal muscle fibers under a microscope. The I bands are composed of thin filaments of the contractile protein actin.
Inspiratory muscle
A muscle whose action is to increase the size of the thoracic cavity; this causes air to be drawn into the lungs, thereby producing inspiration (inhalation).
Lactic acid
A waste byproduct of anaerobic metabolism in skeletal muscle; an end product of the metabolism of carbohydrates. It is created by the conversion of the pyruvate into lactic acid after the fermentation of cellulose. The buildup of lactic acid in a muscle that has been forced into anaerobic mode by over-strenuous activity can cause discomfort.
Lactic acid
A waste byproduct of anaerobic metabolism in skeletal muscle; an end product of the metabolism of carbohydrates. It is created by the conversion of the pyruvate into lactic acid after the fermentation of cellulose. The buildup of lactic acid in a muscle that has been forced into anaerobic mode by over-strenuous activity can cause discomfort.
Linea alba
The sheet of fibrous connective tissue (aponeurosis_ that connects the abdominal muscles from each side on the ventral midline.
Motor unit
One nerve fiber and all the skeletal muscle fibers it innervates. Motor units with small numbers of muscle fibers per nerve fiber are capable of fine, delicate movements.
Multi-unit smooth muscle
The type of smooth muscle composed of individual smooth muscle cells or small groups of cells. Found where small, delicate involuntary contractions are needed. Requires nerve impulses to stimulate its contractions.
Myofibril
Microscopic, fiberlike structures that occupy most of the cytoplasm (sarcoplasm) in skeletal muscle cells. Composed of filaments of the contractile proteins actin and myosin and are packed together longitudinally in the muscle cells.
Myoglobin
A protein in muscle cells that has properties similar to hemoglobin. It can store and release large quantities of oxygen to fuel aerobic metabolic processes in the muscle cells.
Myosin filament
One of two contractile proteins of muscle that slide over each other to produce the shortening of the muscle cell that we refer to as muscle contraction.
Neuromuscular junction
The “connection” between the end bulb of a motor nerve fiber and a skeletal muscle cell.
Perimysium
The fibrous connective tissue layer in skeletal muscle that surrounds groups of muscle fivers and binds them into groups called fascicles.
Sarcolemma
The cell membrane of a muscle cell.
Sarcomere
The basic contracting unit of skeletal muscle. It consists of the actin and myosin filaments between Z lines in a muscle cell. Myofibrils are composed of many sarcomeres stacked end to end.
Sarcoplasm
The cytoplasm of a muscle cell.
Sarcoplasmic reticulum
The organelle in a muscle cell that is equivalent to the endoplasmic reticulum of other cells. It stores calcium ions (Ca2+) necessary to initiate the muscle contraction process. Release of Ca(2+) from the sarcoplasmic reticulum is stimulated by a nerve impulse.
Synergist
Something that aids the action of something else. A synergistic muscle contracts at the same time as a prime mover and assists it can carrying out its action.
Tendon
Fibrous connective tissue bands that connect skeletal muscles to bones.
Transverse tubule
A system of tubules in a skeletal muscle cell that exted from the sarcolemma (cell membrane) into the depths of the cell. They help carry an impulse caused by nerve stimulation of the muscle cell into its interior.
Twitch contraction
A single skeletal muscle fiber contraction. It can be divided into three phases: a brief, latent phase; a longer. contracting phase; and an even longer relaxation phase.
Viscera
the internal organs in the main cavities of the body, especially those in the abdomen, e.g. the intestines
Visceral smooth muscle
The type of smooth muscle found in the walls of many soft internal organs, such as the intestine, urinary bladder, and uterus. Its cells are linked to form large sheets that show rhythmic waves of contraction without external nerve stimulation.
Z line
The dark line in the center of the light band (I band). Discs to which the actin filaments are attached. They look like lines because of the angle they are viewed.
