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Muscular Systems I & II
N/A
98
Anatomy
Undergraduate 1
02/20/2011

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Cards

Term
Musculus
Definition
"Little Mouse"
Term

What are muscles good for?

 

Definition
Movement, Stabilization, Posture, Generating Heat
Term

What is special about muscles?

 

Definition
Contractility, Excitability, Extensibility, and Elasticity
Term
Contraction
Definition
Cells contract and create "pulling" force.
Term
Excitability
Definition
Nerve signals create impulses in plasma membrane of cell which stimulates contraction.
Term
Extensibility
Definition
Muscle tissue can be stretched by contraction of opposing muscles.
Term
Elasticity
Definition
Recoils to original length after being stretched.
Term

3 types of muscle

Definition
Skeletal, Cardiac, and Smooth
Term
Skeletal
Definition
Voluntary striated muscle that you consciously control movement of.  Found in all limbs and body walls.
Term
Striated
Definition
Furrowed or streaked.
Term
Cardiac Muscle
Definition
Involuntary striated muscle, innervated by the autonomic nervous system.  Found ONLY in walls of the heart.
Term
Smooth Muscle
Definition
Involuntary, non-striated muscle, innervated by the autonomic nervous system.  Found in walls of blood vessels and hollow internal organs.  Aids in digestion.
Term
Skeletal Muscle
Definition
Only voluntary muscle in the body.
Term
Fascia
Definition
Fibrous connective tissue that surrounds and separates muscles in the body.
Term
Tendon
Definition
A cord-like fascial extension at the end of the muscle attaching it to the body by the intermingling of collagen fibers with those of the periosteum.
Term
Aponeurosis
Definition
Broad, sheet-like arrangement of fascia attaching muscle to muscle or bone.
Term
Sharpey's Fibers
Definition
Collagen fibers of the periosteum that insert into the underlying bone.
Term
Sharpey's fibers contractile unit
Definition

Collagen fibers of tendons blended with the collagen fibers of the periosteum.

NOT COMMON

Term
Skeletal Muscle (in depth)
Definition
Parallel striated muscle cells (fibers) surrounded by CT fibers.  Capillary beds run parallel to fibers.
Term
Skeletal muscles contract in response to:
Definition
Acetylcholine ONLY
Term
Striated appearance of Skeletal muscle is due to what?
Definition
The arrangement of various myofilaments found within the contractile unit (sarcomeres) of the muscles.
Term
Other muscles contract to what?
Definition
Acetylcholine and neuropenephrine
Term
Sarcomere
Definition
Smallest functional unit of a skeletal muscle cell.  Extends from one z-line to another.
Term
Skeletal muscle cells
Definition
Long, multi-nucleated, cylindrical cells with peripheral nuclei.
Term
Each skeletal muscle cell contains:
Definition
Sarcoplasm, Sarcolemma, and Satellite cells
Term
Sarcoplasm
Definition
Cytoplasm of muscle cells
Term
Sarcolemma
Definition
Plasma membrane and basal lamina of muscle cells.
Term
Satellite Cells
Definition
Found between plasma membrane and basal lamina.  Considered to be stem cells.  Repairs strains and tears in muscles.
Term
Stem cells
Definition
Give rise to form new myoblasts that fuse to form skeletal muscle cells.
Term
Sarcoplasmic Reticulum
Definition
The endoplasmic reticulum of muscle cells composed of two parts: enlarged terminal cisternae (swollen sacs) that are connected by a smaller tubular system - sarcotubules.
Term

T tubules

(Transverse Tubules)

Definition
Invaginations of muscle fiber cell membrane (sarcolemma) from the surface.
Term
Where are T tubules found?
Definition
Between the terminal cisternae of adjacent sarcomeres.
Term
Myofibrils
Definition
A mass of myofilaments (actin and myosin) that occupy the bulk of the cytoplasm.  Provide movement exhibited by muscle when it contracts.
Term
Triad
Definition
Two terminal cisternae, one on each side of a transverse tubule.
Term
What penetrates the muscle cell and wraps around each myofibril?
Definition
Sarcoplasmic reticulum and T-tubule systems
Term
How do muscle cells contract?
Definition
Actin myofilaments slide in over the myosin filaments, pulling Z lines behind them, shortening the sarcomere.  As the sarcomere shortens, the muscle contracts.
Term
Septa
Definition
Pass inward from deep fascia of the limb to compartmentalize muscles.
Term
Epimysium
Definition
Dense connective tissue surrounding entire muscle.
Term
Perimysium
Definition

  • Surrounds bundles of fibers or fascicles.
  • Creates pathway for blood vessels into muscle tissue.

Term
Endomysium
Definition
Delicate, loose CT, investing each muscle fiber.
Term
Each muscle makes contact with a nerve ending where?
Definition
At the neuro-junction (synapse) between the nerve ending and the muscle cell.
Term
Motor end plate
Definition
Depression the synaptic knob sits on in muscle fibers. (Refer to diagram)
Term
Motor/Neuromotor Unit
Definition
One nerve ending and all the muscle cells it contacts.
Term
Ratio of Nerve fibers to Muscle Cells:
Definition
Determines a delicate from a non-delicate muscle and (generally) defines level of control muscles exert on the structures they move.
Term
Cardiac Muscles are found where?
Definition
ONLY in the myocardium (muscular wall) of the heart.
Term
Cardiac Muscle Cells are often referred to as what?
Definition
Cardiocytes
Term
Compared to the size of skeletal muscles, cardiac muscles are typically:
Definition
Small in size.
Term
True or False: Cardiac Muscles are capable of cell division and regeneration.
Definition
False
Term
Union between two or more cardiac muscle cells is made easy by:
Definition
Intercalated Discs
Term
Intercalated Discs
Definition
Specialized junctional connections between adjacent cardiocytes.
Term
Intercalated Discs are composed of:
Definition

2 main structural elements:

 

  • Desmosomes
  • Gap Junctions

Occur at Z lines of the cardiac muscle sarcomere.

 

Term
Desmosomes
Definition
Myofibrils anchor and form a bridge between cells so cells pull together when sarcomeres contract.
Term
Gap Junctions
Definition
Allow ions and molecules to move between cells providing communication between cells.
Term
Smooth Muscle
Definition
Short, spindle shaped cells that have a central nucleus and unorganized sarcomeres.
Term
What do smooth muscles respond to?
Definition
Norepinephrine and Acetylcholine
Term
Neurotransmitters initiate:
Definition
Contraction in some smooth muscle and relaxation in others.
Term
Smooth muscle contracts in response to:
Definition
Stretch of Lumen it surrounds
Term
True or False: Smooth Muscle is slower to contract than Skeletal Muscle and stays contracted longer.
Definition
True
Term
2 arrangements of smooth muscle
Definition
Multi-unit and Visceral
Term
Multi-unit Smooth muscle
Definition
Poorly organized muscle fibers, found in walls of blood vessels and the iris of the eye.  Contract in response to nerve impulses and hormones.
Term
Visceral Smooth Muscle
Definition
Sheets of spindle shaped cells that are held together by gap junctions.
Term
Visceral smooth muscle is found in:
Definition
Hollow organs (EX: stomach, intestines, bladder, uterus) arranged in two thick layers (outer longitudinally directed fibers and inner circularly directed fibers).
Term
Smooth Muscle Cells (in depth)
Definition

  • Have no t-tubules and exhibit poorly developed sarcoplasmic reticulum.  
  • Their nuclei can divide or increase in cell number.

Term
Locations of Smooth Muscle
Definition

  • In walls of all blood vessels (EXCEPT heart).
  • In organized layers in the walls of the respiratory, circulatory, digestive, and reproductive tracts.

Term
Rhythmaticity:
Definition

 

  • Pattern of repeated contractions.
  • Results from self-exciting fibers which spreads to adjacent cells.

 

Term
Example of Rhythmaticity:
Definition
Peristalsis- slow contractile waves of the GI tract that results from fibers stimulating each other.
Term
Axial Musculature
Definition
Muscles that are associated with the axial skeleton. 
Term
Muscles of the head
Definition
Muscles of facial expression and mastication
Term
Muscles of facial expression
Definition

-frontalis

-oribicularis oculi

-orbicularis oris

-zygomaticus major

Term
Sphincters
Definition
tightly close the eye or the mouth
Term
Orbicularis Oculi
Definition
Closes the eyes
Term
Orbicularis Oris
Definition
Closes the mouth
Term
Frontalis
Definition
Elevates the eyebrow, wrinkles forehead
Term
Zygomaticus major
Definition
Elevates the corner of the mouth
Term
Depressor Anguli Oris
Definition
Depresses the corner of the mouth
Term
Platysma
Definition
Tenses the skin and fascia of the neck
Term
Muscles of Mastication
Definition

 

-temporalis
-masseter
-lateral pterygoid
-medial pterygoid

These 4 muscles act directly on the mandible for chewing (mastication).

 

Term
Temporalis
Definition
Closes and RETRACTS the mandible.  All others close and PROTRACT the mandible.
Term
Muscles of the Oral Cavity
Definition
Genioglossus
Term

Muscles of the head

Extraocular Muscles

Definition

rectus muscles

-lateral rectus

-medial rectus

-superior rectus

-inferior rectus

superior oblique

inferior oblique

Term
Eye Pneumonic
Definition
LR6[SO4]3
Term
Muscles of the neck
Definition

sternocleidomastoid = sterno (sternum) cleido (clavicle) and mastoid process

-divides the neck into two triangles, the anterior and posterior.

Term
Accessory Nerve
Definition
Rotates and orients the face cranially
Term
Hyoid Bone
Definition

Has numerous thin, flat, strap like muscles that attach to it.  Aid in swallowing and also can move the larynx.

Divided into:

Suprahyoids- strap-like muscles above the hyoid.

Infrahyoids- strap-like muscles below the hyoid.

Term
Muscles of the trunk
Definition

Muscles of the thoracic wall: composed of 3 layers superficial to deep:

-external intercostals

-internal intercostals

-innermost intercostals (not see from exterior)

Found between ribs.

Term
Muscles of the anterolateral abdominal wall:
Definition

-external oblique

-internal oblique

-transversus abdominis

These muscles are innervated by the ventral rami of spinal nerves.

Term
Superficial muscles of the back:
Definition

-splenius capitis

-levator scapulae

-rhomboids

-trapezius

Term
Deep muscles of the back:
Definition

Referred to as erector spinae muscles.

(Postural) responsible for flexing/extending the spine

Term
Serratus posterior superior and inferior:
Definition

Act as fascial retinacula holding the deeper muscle group in place (like seatbelts).

-Supplied by the dorsal ramus of each spinal nerve that is crossed.

Term
Muscle Location
Definition

Usually indicated within name.

EX: brachialis located in arm. (brachium=arm)

&

intercostals are muscles between the rib (costal=rib)

&

flexor pollicis brevis is a thumb muscle (pollicis=thumb)

Term
Relative Position Terms
Definition

Lateral-towards the outside

Medial-towards the middle

Intermediate-between

Internal-within

External-outside

Term

Vastus Lateralis

Vastus Intermedius

Vastus Medialis

Definition

-Lateral muscle in the anterior thigh.

-Intermediate muscle of the anterior thigh.

-Medial most muscle in the anterior thigh.

Term
Shape: Muscles are named for particular shapes.
Definition

EX:

Deltoid (delta=triangle)

Trapezius (two halves together form a trapezoid)

Rhomboid (major and minor are shaped as a rhombus)

Biceps Brachii (spindle shaped)

Term
Examples of Relative Sizes of Muscles:
Definition

Max-imus

Min-imus

Medi-us

Long-us

Brev-is

Gluteus Maximus is large.

Gluteus Medius is intermediate.

Gluteus Minimus is small.

Term
Direction of Fascicles:
Definition

Specific names of muscles sometimes reflect the direction of the muscle fibers.

EX: rectus = fibers run in straight lines parallel to body's axis.

-Oblique running fibers travel "obliquely" to the midline.

Term
Locations of Attachments (Origin and Insertions):
Definition

Most muscles have 2 bony attachments, one called the origin (proximal attachment) is the least movable, and insertion (distal attachment) is the more movable.

EX: brachioradialis originates at the brachium and inserts on the radius.

Term
Number of Origins:
Definition
Muscles that have more than one origin (2 heads) are sometimes indicated by the terms biceps (2 heads), triceps (3 heads), or quadriceps (4 heads).
Term

Use what you know to determine the meaning of a bone by the name:

Extensor Carpi Radialis Longus

Definition

Extensor: Extends

Carpi: Wrist

Radialis: Lies along the Radius of the forearm.

Longus: This muscle is longer than others, such as the brevis.

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