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Anatomy
Unit 3-Muscular System
89
Anatomy
Undergraduate 1
03/01/2012

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Cards

Term
Functions of Muscle Tissue
Definition

1. Produce body movements

2. Stabilize body positions

3. Regulate organ volumes-bands of smooth muscle called sphincters

4. Movement of substances within the body-blood, lymph, urine, air, food/fluids, sperm

5. Produce heat-involuntary contractions of skeletal muscle (shivering)

Term
Types of muscle tissue
Definition

1. Skeletal

2. Cardiac

3. Smooth

Term
Basic characteristics/properties of muscle tissue
Definition

1. Excitability

2. Contractility

3. Extensibility

4. Elasticity

Term
Excitability
Definition

The ability to respond to stimulation:

-Skeletal muscles normally respond to stimulation by the nervous system.

-Cardiac and smooth muscles respond to the nervous system and the endocrine system (circulating hormones)

Term
Contractility
Definition
The ability to shorten actively and exert a pull or tension that can be harnessed by connective tissues
Term
Extensibility
Definition
The ability to continue to contract over a range of resting lengths
Term
Elasticity
Definition
The ability of a muscle to rebound toward its original length after a contraction.
Term
Characteristics of smooth muscle
Definition

1. Spindle-shaped cells with one centrally located nucleus

2. Cytoplasm looks smooth-no striations; microfilaments spiral down the cell like a barber shop pole

3. Cells form into sheets in walls of organs and vessels

4. Have the ability to regenerate

5. Help push solids/fluids along digestive tract

Term
[image]
Definition
Smooth Muscle Tissue
Term
Characteristics of cardiac muscle
Definition

1. Branching cells/fibers

2. One or two centrally located nuclei per cell

3. Contain myofibrils that are regularly arranged (striated), but are difficult to distinguish because of irregular branching cells with varying width-->irregularity due to a larger number of mitochondria

4. Cells held together by intercalated discs

5. No regeneration

Term
Roll of intercalated discs
Definition
Allow ions to pass easily between cells and allow neuronal signals to transmit between cells simultaneously
Term
[image]
Definition
Cardiac Muscle
Term
Characteristics of Skeletal Muscle
Definition

1. Contractile organs directly or indirectly attached to bones of the skeleton

2. Striations formed by myofibril arrangements

3. Have the ability to regenerate

 

Term
Functions of Skeletal Muscles
Definition

1. Produce skeletal movement

2. Maintain posture and body position

3. Support soft tissues

4. Regulate entering and exiting of material

5. Maintain body temperature

Term
[image]
Definition
Skeletal Muscle
Term
Ways to name skeletal muscle
Definition

1. Specific body regions

2. Shape of the muscle

3. Orientation of muscle fibers

4. Specific or unusual features

5. Identification of origin and insertion

6. Primary functions

7. References to actions

Term
Muscle Organization
Definition

1. Endomysium

2. Perimysium

3. Epimysium

Term
Endomysium
Definition
CT surrounds individual muscle cells/fibers outside of cell membrane
Term
Perimysium
Definition

CT surrounds fascicles

-attachment site for nerve and blood vessels

Term
Fascicle
Definition
Bundle of muscle cells
Term
Epimysium
Definition

CT surroinds the entire muscle

-attachment site for nerves and blood vessels

Term
Flat, sheet-like tendon
Definition

Aponeurosis

-Formed by combining of Endomysium, perimysium, and epimysium

Term
[image]
Definition
Muscle Fiber Organization
Term
Sarcomere structure
Definition

-All myofibrils are arranged parallel to the long axis of the cell with sarcomeres laying side by side

-Myosin (thick) and actin (thin) filaments are arranged within a myofibril and organized in sarcomeres (z line to z line)

Term
[image]
Definition
Myofilaments
Term

Size of thick and thin filaments

(exact and relative)

Definition

Thick: 10-12 nm diameter, 1.6 micrometer length

--Larger than thin filaments

 

Thin: twisted interacting proteins 5-6 nm diameter, 1 micrometer length

--smaller than thick filaments

Term

Naming of muscle fibers

(Muscle fiber organization)

Definition

1. Parallel

2. Convergent

3. Unipennate

4. Bipennate

5. Multipennate

6. Circular

Term

Parallel muscle fiber organization

example

Definition

fibers run parallel to the long axis of the muscle

biceps brachii

Term

Convergent muscle fiber organization

example

Definition

Muscle fibers converge from a wide area to a small area

Pectoralis major

Term

Unipennate muscle fiber organization

example

Definition

Muscle fiber at an angle on one side of the tendon

Extensor digitorum

Term

Bipennate muscle fiber organization

example

Definition

Muscle fibers at an angle on both sides of the tendon

Rectus femorus

Term

Multipennate muscle fiber organization

example

Definition

Muscle fibers converge from a wide area to a small area.  The tendo branches within the muscle

Deltoid

Term

Circular muscle fiber organization

example

Definition

Muscle fibers concentrically arranged around an opening

eye, mouth

Term

Muscle origin

(part of OIAs)

Definition
Origin remains stationary-point of less movement
Term

Muscle insertion

(part of OIAs)

Definition
Insertion is the point of more movement
Term
Exceptions to the origin insertion rules
Definition

1. If the muscle extends from a broad aponeurosis to a narrow tendon (frontalis), aponeurosis =origin; tendon=insertion

2. If there are several tendons at one end and only one at the other (pectoralis major), multiple tendon end=origin; single tendon end=insertion

Term

Muscle action

(part of OIAs)

Definition

1. Reference the bone region affected

(flexion of the forearm)

2. Specifies the joint involved

(felxion of the elbow)

Term
Primary actions
Definition

1. Prime movers

2. Synergists

3. Antagonists

Term
Prime movers
Definition
Agonists-primarily responsible for producing a particular movement
Term
Synergists
Definition
assist the prime mover in performing that action
Term
Antagonists
Definition
muscles whose actions oppose that of the agonist
Term
Trigger for muscle contraction
Definition
Ca ions in the sarcoplasm
Term
Beginning of a contraction
Definition

1. Nerve impulse reaches an axon terminal and synaptic vesicles release acetylcholine (ACh)

2. ACh diffuses to receptors on the sarcolemma and Na+ channels open--Na+ rushes into the cell

3. A muscle action potential spreads over the sarcolemma and down into the T-tubes

4. Sarcoplasmic reticulum releases Ca ions into the sarcoplasm

5. Ca ions bind to troponin and causes troponin-tropomyosin complex to move and reveal myosin binding sites on actin--->the contraction cycle begins

Term

Muscle Tone

 

Definition

continuous contraction that produces a resting tension in skeletal muscle

-stabilizes the position of bones and joints

Term
Motor unit
Definition
neuron and all the muscle cells it stimulates
Term
Muscle Hypertrophy
Definition

Exercise causes an increase in

-number of mitochondria

-Glycogen reserves

-Myofibrils

 

*Causes enlargement of the stimulated muscle

Term
Muscle atrophy
Definition
Disuse of muscle causes shrinking (opposite of hypertrophy)
Term
Fast fiber(white fibers) features
Definition

-Large in diameter because of many densely packed myofibrils

-Large glycogen reserves

-Relatively few mitochondria (mitochondria are unable to meet the demand)

-Fatigue easily

-Can contract in .01 sec or less followinf stimulation

-Anaerobic movements for short duration

(dominant in weight lifters and sprinters)

Term
Types of skeletal muscle fibers
Definition

1. Fast fibers

2. Slow fibers

Term
Slow fibers (red fiber) features
Definition

-half the diameter of fast fibers

-take 3 times as long to contract after stimulation

-contain abundant mitochondria

-use aerobic metabolism

-have more extensive network of capillaries that muscles dominated by fast muscle fibers

-are red due to pigment called myoglobin

-Prolonged, sustained contractions for maintaining posture

(dominant in marathon runners)

Term
Aging and the Muscular system
Definition

-Skeletal muscle fibers become smaller in diameter

-Skeletal muscles become less elastic

-Tolerance for exercise decreases

-ability to recover from injury decreases

Term
Rigor Mortis
Definition

-State of muscular rigidity that begins 3-4 hours after death and lasts about 24 hours

-After death, Ca2+ ions leak out of the sarcoplasmic reticulum and allow myosin heads to bind to actin

-Since ATP synthesis has ceased, crossbridges cannot detach from actin until enzymes begin to digest decomposing cells

Term

Muscular Distrophy

What is it?

What is occuring?

What is affected?

Definition

MD

-Group of rare inherited muscle diseases in which muscle fibers are unusually susceptible to damage

-Primarily voluntary muscles become weaker

-In the later stages, fat and connective tissue often replace muscle fibers

-In some types of MD, heart and other involuntary muscles are affected

Term
Causes of MD (types of MD)
Definition
There are 9 major types, but the most common is due to genetic deficiency of the muscle dystrophin
Term
Dystrophin
Definition
Protein involved in maintaining the integrity of the muscle fiber
Term

Cure for MD

Therapy

Definition

No cure

 

-Respiratory therapy

-Physical therapy

-Steroids and corrective orthopedic surgery may be needed

-Cardiac abnormalities may require a pacemaker

Term
[image]
Definition
Tyoes of Muscle Fiber Organization
Term
[image]
Definition
Skeletal Muscle Slide
Term

Sliding filament theory

Location of action

Definition
Occurs at the junction of a motor neuron to a skeletal muscle fiber (neuromuscular junction)
Term
Sliding filament theory steps 1-6
Definition

1. Acetylcholine (ACh) is realeased by the motorneuron and passed to the sarcolemma.

2. ACh spreads over the entire sarcolemma

3. Na+ ions are spread through the cell via T-tubes as a result of the ACh

4. T-tubes spread the action potential through the cell

5. This causes the sarcoplasmic reticulum to open Ca channels initiating a muscle contraction

6. The released Ca2+ ions bind with proteins (troponin-tropomyosin complex) on actin, which causes the protein complex to expose a myosin binding site on actin

Term
Sliding filament theory steps 7-12
Definition

7. The myosin heads (crossbridges) have an ATP molecule that has low affinity for actin

8. ATP is split into ADP and an inorganic phosphate (usable form of energy)

9. The myosin heads cock allowing them to bind with the exposed binding site on actin

10. The loss of the inorganic phosphate causes the myosin heads to swivel from 90 deg to 45 deg, moving the attached actin

11. The movement brings the Z-lines together, shortening the sarcomere, resulting in the contraction

12. The contraction continues while ATP and Ca+ are still available in the cell.  A max contraction occurs when myosin butts from Z-line to Z-line 

Term

Sliding filament theory

Ending a contraction

Definition

Electrical stimulation ends

-Sarcoplasmic reticulum recaptures the Ca2+ ions

-Troponin-tropomyosin complex cover the active sites

-contraction ends

Term
Relaxation of muscle
Definition

1. acetylcholinesterase breaks down ACh within the synaptic cleft

2. Muscle action potential ceases

3. Ca2+ ion channels close

4. Active transport pumps Ca ions back into storage in the sarcoplasmic reticulum

5. Ca binding protein (calsequestrin) helps hold Ca ions in SR

6. Troponin-tropomyosin complex recovers binding site on the actin

Term
[image]
Definition
Cat Leg Muscles
Term
[image]
Definition
Cat Arm Muscles
Term
[image]
Definition
Cadaver Arm Muscles
Term
[image]
Definition
Abdominal Muscles
Term
Buccinator OIA:
Definition

O: Mandible and maxillae

I: Orbicularis Oris

A: Blowing, compress cheek

Term
Masseter OIA
Definition

O: Zygomatic arch and maxillae

I: Coronoid process, ramus of mandible

A: Elevation of mandible, chewing

Term
Zygomaticus major OIA
Definition

O: Zygomatic bone

I: Angle of mouth (obicularis oris)

A: Smiling

Term
Sternocleidomastoid OIA
Definition

O: Clavicle and sternum

I: Mastoid process, superior nuchal line

A: tilt and rotate head, flex neck

Term
Rectus Abdominus OIA
Definition

O: Pubis

I: Costal cartilage, ribs 5-7, xiphoid process

A: Flex back

Term
Trapezius OIA
Definition

O: Superior nuchal line, spinous process C7-T12

I: Acromion process of clavicle, spine of scapula

A: rotation, retraction, elevation and depression of scapula

Term
Biceps Brachii OIA
Definition

O: Short head: coracoid process of the scapula

Long head: glenoid cavity

I: Radial tuberosity

A: Flex elbow, supinate forearm

Term
Extensor digitorum OIA
Definition

O: Lateral epicondyle of humerus

I: Middle and distal phalanges

A: Extend wrist, hand, fingers

Term
Sartorius OIA
Definition

O: Anterior superior iliac spine

I: Tibia (Anterior and medial side)

A: Flex knee and hip

Term
Rectus Femoris OIA
Definition

O: Anterior inferior iliac spine

I: Patella (tendon)

A: Extend knee, flex hip

Term
Gastrocnemius OIA
Definition

O: Lateral and medial condyles of femur

I: Calcaneous

A: Plantarflexion

Term
[image]
Definition
Head and Neck Muscles
Term
[image]
Definition
Eye Muscles
Term
[image]
Definition
Vertebral Muscles
Term
[image]
Definition
Intercostal Muscles
Term
Axial Muscles fall into 4 groups
Definition

1. Muscles of the head and neck

2. Muscles of the vertebral column

3. Oblique and rectus muscles

4. Muscles of the pelvic floor

 

Term
Groups of the head and neck muscles
Definition

1. Muscles of facial expression

2. Muscles of the eye

3. Muscles of mastication

4. Muscles of the neck

5. Muscles of the tongue

6. Muscles of the pharynx

Term
Layers of the back muscles
Definition

1. Superficial: move the neck

2. Intermediate: extend the vertebral column

3. Deep: interconnect vertebrae

Term
[image]
Definition
Muscles of the Back
Term
[image]
Definition
Arm Muscles Medial
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