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Flashcards in Quiz 3 Deck (15)
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Dense fibrous connective tissue much like a tendon but organized into a thin sheet of tissue OR
A broad sheet of fibrous connective tissue that attaches certain muscles to bones or to other muscles.
EXAMPLE: the linea alba


Brachiocephalicus muscle

Runs from the arm to the head. It pulls the limb (front leg) forward, extends the shoulder, and depresses and pulls the head and neck laterally (extends head and neck).


Sternocephalicus muscle

Attaches the sternum to the head. It depresses the head and neck and/or draws the head and neck to the side (flexes the head and neck).


Abdominal muscles

From most superficial to deepest:
1. Rectus abdominis muscle (6-pack)
2. External abdominal oblique muscle
3. Internal abdominal oblique muscle
4. Transversus abdominis muscle
They are arranged in layers and the left and right parts of each muslce meet on the ventral midline at the linea alba (which is an aponeurosis).


Functions of the abdominal muscles

Support the abdominal organs
Help flex the back
Participate in various functions that involve straining
Play a role in respiration


Semimembranosus muscle

It is wedged between the biceps femoris muscle laterally and the gracilis and adductor muscles medially. It extends the hip and flexes the stifle.


Semitendinosus muscle

This straplike muslce lies medial to the biceps femoris muscle and lateral to the semimembranosus muscle. It extends the hip, flexes the stifle, and extends the tarsal joints.


Inspiratory muscles

1. Diaphragm: Thin, dome-shaped muscular structure that forms the boundary between the thoracic and abdominal cavities.
2. External intercostal muscles
When we breath in, the diaphragm goes flat, the thoracic cavity expands and a negative pressure is created.



Basic contracting unit of skeletal muscle. Each myofibril is made up of many sarcomeres lined up end to end (area from one Z line to the next Z line).
It consists of the actin and myosin filaments between Z lines in a muscle cell.


Neuromuscular junction

The connection between the end bulb of a motor nerve fiber and a skeletal muscle cell. There is actually a tiny space, called the synaptic space, between the end of the nerve fiber and the sarcolemma of the muscle fiber.



An enzyme in the synaptic space that removes/breaks down acetylcholine (so muscles don't spasm)
Acetylcholine is a neurotransmitter associated with somatic nerves and with parasympathetic nervous system effects even though it is used in the preganglionic neuron in both the sympathetic and parasympethetic nervous systems; has a stimulatory effect on the GI tract, it increases secretions and muscle contractions in the esophagus, stomach, ruminant forestomachs, intestine, and colon.


Anaerobic metabolism

Used if oxygen need exceeds oxygen supply
Results in lactic acid formation, which causes discomfort (muscle pain)
Non-oxygen dependent metabolism. The type of metabolism in muscle that occurs when the need for energy to produce muscular activity exceeds the available oxygen supply. Anaerobic metabolism is not as efficient as aerobic metabolism and results in the formation of lactic acid as a byproduct. Lactic acid can cause discomfort in muscle tissue and requires oxygen to be converted back to glucose.


Intercalated disks

End-to-end attachment sites between adjacent cardiac muscle cells. The intercalated disks securely fasten the cells together and also transmit impulses from cell to cell. This allows large groups of cardiac muscle cells to function as a large single unit.


SA node

Sinoatrial node - The natural pacemaker of the heart
A group of specialized cardiac muscle cells in the wall of the right atrium of the heart that act as the heart's pacemaker. The impulse that starts each heartbeat is initiated in the SA node.


Spindle-shaped smooth muscle cells

Smooth muscle cell, small, spindle-shaped (or sweet potato shaped) with a single nucleus
Actin and myosin filaments arranged as small contractile units that crisscross the cell (attached at both ends to "dense bodies" that correspond to the Z lines of skeletal muscle)