a&p unit 4 exam

What are the three types of muscle tissue?

Skeletal, smooth, & cardiac muscle

describe skeletal muscle:

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a __striated & voluntary__ tissue, located in skeletal muscles, whose (fibers) cells are multinucleated. 

describe smooth muscle:

 a nonstriated & involuntary tissue, located in the wall of hollow visceral organs (such as the stomach), whose cells are uninucleate.

describe cardiac muscle:

a __striated & involuntary__ muscle, located in the heart, whose cells are uninucleate. 

What does striated mean regarding muscle tissues?

Refers to the alternating dark & light bands visible through a microscope 

Structure of muscular system:

skeletal muscle, tendons, & aponeurosis

Function of the muscular system: (1)

Movement: as a skeletal muscle contracts, tension (force) develops. Generally, this force is transmitted in such a way that a muscle’s insertion (moveable

Function of the muscular system: (2)

 Maintenance of posture

Function of the muscular system: (3)

 Production of heat for thermoregulation

Define tendon:

a cord-like structure made of dense connective tissue which transmits force from a skeletal muscle to a bone. 

Define aponeurosis:

a flat sheet of dense connective tissue which joins muscle to muscle 

Approximately, how many skeletal muscles occur?

406

**Define myo:**

muscle

Define sarco:

**denoting flesh or striped muscle**

Define fiber:

cell for muscles

Define fascicle:

small bundles of nerve or muscle fibers enclosed by connective tissue

Define fascia:

connective tissue between skin & bones

describe Sarcolemma:

the cell membrane of a muscle fiber

describe Transverse tubule:

 **inward extension from the sarcolemma which conducts impulses into the muscle fiber** 

describe Sarcoplasmic reticulum:

 smooth endoplasmic reticulum specialize for the storage & release of calcium ions (Ca+2)

Sarcoplasm:

 **the cytoplasm of a muscle fiber** 

describe Myofibrils:

 **a cylindrical bundles of contractile proteins**

What do myofibrils include?

actin & myosin

describe Actin:

**thin myofilament protein. Actin possesses binding sites for attachment of myosin “heads” to form cross-bridges during contraction.** 

describe Myosin:

 thick myofilament. Myosin possesses “heads” which form cross-bridge links to actin’s binding sites during contraction.

describe Troponin & Tropomyosin:

inhibit actin’s binding sites prior to and after contraction.

How are actin & myosin arranged?

**Into sarcomeres**

Describe sarcomere:

 the basic unit of striated muscle tissue

Describe z lines:

**functional unit of a skeletal muscle fiber** 

Describe I band:

**actin only; during contraction, it becomes smaller & disappears.**

Describe A band:

**actin & myosin; during contraction, it remains the constant length.** 

Describe neuromuscular junction:

the point at which a motor neuron provides the Ach stimulus to a muscle fiber’s sarcolemma

Describe synaptic vesicles:

**releases ACh, which provides the stimulus to the muscle fiber’s sarcolemma** 

Describe acetylcholine ACh:

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**provides the stimulus for muscle contraction**

**Describe events of skeletal muscle fiber relaxation.** 

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* ACh is decomposed by the enzyme AChE (acetylcholinesterase) 
* Calcium ions  are actively transported back into the SR 
* Myosin cross-bridge links release from actin’s binding sites 
* The sarcomere resumes its resting length 

What is the 1st energy source (immediate energy source)?

**ATP is the source of energy for muscle fibers.** 

What is the 2nd energy source?

**creatine phosphate** donates energy to regenerate ATP.

What is the 3rd energy source?

**glucose** is initiated to supply energy to regenerate ATP.

What is the 4th energy source?

**Glycogen** reserves are mobilized to supply energy sources.   

What is required for the aerobic stages of cellular respiration of glucose?

**oxygen**

When there’s insufficient oxygen, muscle fibers initiate the production of?

Lactic acid 

what contributes to muscle fatigue and eventually to muscular soreness?

lactic acid

During intense muscle activity, what develops as muscle fibers produce and accumulate lactic acid?

oxygen debt

within skeletal muscle fibers, what protein temporarily stores oxygen?

myoglobin

“fast” muscle fibers contain ____ ____ and appear what color?

little myoglobin; pale/whitish

what type of muscle fibers are specialized for rapid responses to stimulus, but will fatigue rapidly?

fast muscle fibers

**“slow” muscle fibers** contain ____ ____ & appear ____/_____ in color.

abundant myoglobin; dark/reddish

what kind of fibers respond relatively slowly to stimuli, but are specialized for endurance

slow muscle fibers

contraction/relaxation period:

 **a single response of a muscle to a single stimulus.** 

describe Minimum in twitch response

the stimulus must be of “threshold” intensity or greater.

latent period:

time in which the impulse travels across the sarcolemma, into the T-tubules, and into the SR.

label the diagram for the twitch response

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Define tonus:

**the natural and continuous slight contraction of a muscle**

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Define isometric contraction:

**contraction that tenses a muscle, but does not produce joint movement.** 

Define isotonic contraction:

contraction that produces movement

Define atrophy:

**decrease in size (and strength) of a muscle** 

Define hypertrophy:

 **increase in size (and strength) of a muscle** 

**Describe the relationship between bones & skeleton muscles in producing movement.** 

muscles are attached to bones by tendons at their origins and insertions. Skeletal muscles produce movements by pulling on the bones.

Define origin:

the attachment point of a muscle to a stationary bone

Define insertion:

**the attachment point of a muscle to a moveable structure (ex: bone)**

Define innervation:

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**the nerve supply of a muscle** 

define action:

 the movement produced when a muscle contracts (ex: elevation, flexion, adduction, etc.)

**Define agonist** (primer mover)**:**

**the primary muscle that contracts to produce an action (primer mover)**

Define synergist:

 a muscle which assists a prime mover

Define antagonist:

a muscle with an opposite action of the prime mover

Describe ways in which skeletal muscles are named

**direction, location, size, number of origins, & origin & insertion**

Describe ways in which skeletal muscles are named

 **direction, location, size, number of origins, & origin & insertion**

Define rectus:

fibers run parallel to the body’s midline

Define oblique:

fibers run diagonal to the midline 

Define transverse:

 fibers run at a right angle to the midline (perpendicular to the midline)

Define major:

large

Define minor:

small

Define minimus:

smallest

Define medius:

medium-sized

Define maximus:

largest

Define longus:

longest

Define brevis:

shortest

Location:

bone names often reflect associated skeletal components

Frontalis (a muscle of facial expression):

 elevates eyebrows

Temporalis (a muscle of mastication):

elevates the mandible 

Masseter:

 elevates the mandible during mastication 

Orbicularis oculi (a muscle of facial expression):

closes the eye

Zygomaticus (a muscle of facial):

elevates the upper lip 

Sternomastoid (sternocleidomastoid) -

rotates the head

Pectoralis major-

medially rotates humerus, adducts humerus 

Abdominal muscles (external oblique, internal oblique, rectus abdominis, transversus abdominis) –

compress & flex the abdomen

Deltoid:

abducts the humerus 

Biceps brachii

flexes the elbow

Flexors located in the anteriorly in the forearm:

flex wrist

Sartorius:

laterally rotates the thigh

Adductor longus:

adducts the femur

Gracilis:

adducts the thigh 

Quadriceps femoris:

 extend the knee

Tibialis anterior:

dorsiflexes the foot 

Trapezius:

extends/ hyperextends the head 

Infraspinatus:

adducts the humerus 

Triceps brachii-

 extends the elbow 

Extensors located posteriorly in the forearm:

extend wrist or phalanges

Gluteus maximus:

extend & rotate the femur

Gluteus medius:

rotates the femur