Unit V Flashcards
Functions of Muscle Tissue
- Movement
- Maintenance of Posture
- Respiration
- Heat generation
- Communication
- Constriction of organs and blood vessels
- Pumping blood
Properties or Characteristics of Muscle
Contractility
Excitability
Extensibility
Elasticity
___ is the ability of muscle cells to forcefully shorten
Contractility
the muscle that contracts (biceps)
agonist
the muscle that relaxes during contraction (triceps)
antagonist
___ is the ability of a muscle fiber to respond rapidly to a stimulating agent
Excitability (responsiveness)
___ is the ability of a muscle to be stretched
Extensibility
___ is the ability to recoil or bounce back to the muscle’s original length after being stretched
Elasticity
Three types of muscle tissues in the body
- Skeletal Muscles
- Cardiac Muscles
- Smooth Muscles
___ muscles have the ability to contract and cause movement
Skeletal Muscles
3 characteristics of skeletal muscle
- striated, tubular, multinucleated
- attached to the skeleton
- voluntary
___ muscles act not only to produce movement but also to stop movement, like resisting gravity to maintain posture
Skeletal muscles
___ muscles are located throughout the body at the openings of internal tracts to control the movement of various substances
Skeletal muscles
The structure of muscles
Muscle
Fascicles
Muscle Fiber Cells
Myofibrils
Thick and thin filaments
___ is a fibrous connective tissue which attaches muscle to bone
and serves to move the structure
Tendon
___ is connective tissue to provide support, shape, and suspension for most of the soft tissues of the body.
Fascia
___ are made of layers of delicate, thin sheaths, these also act as fascia
aponeuroses
___ is the fibrous tissue surrounding the skeletal muscle, allows a muscle to contract or move powerfully while maintaining its structural integrity
Epimysium
___ is a sheath of connective tissue that groups muscle fibers into bundles (between 10 & 100 or more) or fascicles which plays in transmitting lateral contractile movements
Perimysium
___ (meaning within the musles) is the key element that separates single muscle fibers from one another
Endomysium
___ allows autonomous gliding in contraction and is highly deformable tissue that adapts changes during the muscle contraction
Endomysium
___ are a group of muscle fibers “bundled” as a unit within the whole muscle
Fascicle
Fascia are covered by a layer of connective tissue called ___
perimysium
___ determine what type of movement a muscle can make and they work in tandem
Fascicle arrangements
this muscle FLEXES the forearm
Biceps brachii
this muscle EXTENDS the forearm
triceps brachii
these muscles FLEX the leg
hamstrings
these muscles EXTEND the leg
quadriceps femoris
these muscles FLEX the fingers
Flexor digitorum superficialis and flexor digitorum profundus and the hand at the wrist
these muscles EXTEND the fingers and the hand at the wrist
extensor digitorum
Every muscle fiber is supplied by the ___, which signals the fiber to contract
axon branch of a somatic motor neuron
Skeletal muscle fibers are made when ___ fuse together
myoblasts (muscle cells)
muscle fiber is surrounded by a plasma membrane called the ___, which contains sarcoplasm, the cytoplasm of muscle cells
sarcolemma
___ is the cytoplasm of muscle cells
sarcoplasm
It acts as a barrier between the extracellular and intracellular compartments, defining the individual muscle fiber from its surroundings
sarcolemma
___ is a series of closed saclike membranes, that forms a cufflike structure surrounding a myofibril
Sarcoplasmic Reticulum
It serves as the storage of intracellular calcium needed for the initiation of muscle contraction
Sarcoplasmic Reticulum
___ are made up of thick (myosin) and thin (actin) myofilaments, which help give the muscle its striped appearance
Myofibrils
THICK myofilaments
myosin
THIN myofilaments
actin
___ are very long chains of sarcomeres, that are the contractile units of the cell
Myofibrils
Myofibrils are very long chains of ___, that are the contractile units of the cell
sarcomeres
Along with actin and myosin. There are two other muscle proteins:
tropomyosin and troponin
Skeletal Muscle Contraction
Stimulus ->
acetylcholine is released ->
Protein receptors detect it ->
Muscle impulse spreads ->
calcium is released to the sarcoplasm ->
myosin sites on the actin filaments are exposed ->
sarcomeres shorten and contract ->
acetylcholinase (enzyme) decomposes the acetylcholine ->
linkages between myosin and actin are broken ->
Relaxation occurs
a neurotransmitter involved in muscle contraction
acetylcholine
an enzyme that decomposes the acetylcholine
acetylcholinase
___ is the critical source for muscle contractions because it breaks the myosin-actin cross-bridge, freeing the myosin for the next contraction
AdenosineTriphosphate (ATP)
Energy sources for muscle contraction
A. AdenosineTriphosphate (ATP)
B. Creatine phosphate (Phosphocreatine)
C. Creatinine phosphokinase
___ serves as high-energy reservoir in striated muscle, brain, retina, inner ear, spermatozoa, and, to a lesser degree, smooth muscle, which are tissues that can consume ATP rapidly
Creatine phosphate (Phosphocreatine)
In the process of regeneration of ATP, creatine phosphate transfers a high-energy phosphate to ___
adenosine diphosphate (ADP)
___ promotes the synthesis of creatinine phosphate
Creatinine phosphokinase
the chemical process inside the cells that consume oxygen to produce usable energy is known as ___
cellular respiration
During this process, energy is converted from glucose, in the presence of oxygen, into ATP molecules
cellular respiration
___ is stored inside muscle cells and it is readily available to produce ATP quickly
Phosphocreatine (creatine phosphate)
___ carries blood to the muscles
Hemoglobin
Oxygen in blood located in the muscle is termed as ___
myoglobin
During rest or moderate activity, is there enough oxygen to support aerobic respiration?
True
Oxygen deficiency may develop during strenuous exercise, and lactic acid
accumulates as an end product of this type of respiration
anaerobic respiration
This is the amount of oxygen needed to oxidize lactic acid to glucose, carbon dioxide and water
oxygen debt
explains why we continue to breathe deeply and quickly for a while after exercise
oxygen debt
muscles loses its ability to contract
Muscle Weakness
Causes of Muscle Weakness
Strenuous activity
Heart failure
Sepsis
this accumulates during anaerobic respiration
lactic acid
Muscle weakness process
causes ->
Decreased flow of blood and oxygen ->
Lactic Acid Accumulation ->
Lactic acid build up in the bloodstream over glucose ->
High lactic acid accumulation in the blood stream ->
Intracellular acidosis
otherwise known as prolong relaxation
Lactic Acid Accumulation
a burning sensation that is associated with a buildup of acid in the muscles during intense exercise
soreness
lactic acid buildup is also known as ___
acidosis
otherwise known as fatigability
Intracellular acidosis
Why is lactate bad?
they produce hydrogen ions which lower the muscle pH, decreasing muscle efficiency, and causing that awful burning sensation
good guy ions
lactate
bad guy ions
hydrogen ions
Causes of Muscle Cramps
Vigorous activity
Dehydration
Holding a position for a long time
Muscle strain
the most common cause of cramps
dehydration
How muscle cramps form
Inadequate ATP in the muscle cells ->
Failure of calcium ions to return back to the sarcoplasmic reticulum ->
Prolong muscle contraction
also known as a prolonged muscle contraction
muscle cramps
during muscle contraction, the length of the muscle remains the same
Isometric contraction
during muscle contraction, the length of the muscle shortens
Isotonic contraction
during muscle contraction, the tension of the muscle increases
Isometric contraction
during muscle contraction, the tension of the muscle remains the same
Isotonic contraction
during muscle contraction, sarcomere which can shorten do so by stretching those which do not
Isometric contraction
during muscle contraction, individual sarcomere shorten which adds up to the shortening of the whole muscle
Isotonic contraction
during muscle contraction, no external work down
Isometric contraction
during muscle contraction, external work is down
Isotonic contraction
muscle contraction when trying to lift heavy weights (when the weights aren’t actually lifted)
Isometric contraction
muscle contraction when you lift weights
Isotonic contraction
2 types of isotonic contraction
concentric
eccentric
Muscular Responses
Threshold stimulus
All or None Response
refers to the minimum intensity required from a stimulus to produce a response from a person
Threshold stimulus
When a muscle contracts, it contracts to its full extent or none at all
All or None Response
___ muscle is striated muscle that is present only in the heart
Cardiac muscle
qualities of cardiac muscle
- striated, branched, uninucleated
- occurs in walls of the heart
- involuntary
___ muscles are found in the intestines, brain, and other organs
Smooth muscles
qualities of smooth muscle
- spindle-shaped, non-striated, uninucleated
- in the walls of internal organs
- involuntary
What are muscle made of?
Water
Proteins
Minerals
Organic Compounds
How much water is in muscles?
75-80%
What are the 3 types of proteins muscle are made of?
Structural
Contractile
Enzymatic
collagen and elastic are examples of this protein
structural protein
myosin, actin, troponin, and tropomyosin are examples of this protein
contractile protein
adenosine triphosphate, creatinine phosphatase, and lactic dehydrogenase are examples of this protein
enzymatic protein
Muscle is attached to the immovable or less movable bone
Origin
Muscle is attached to the movable bone, and when the muscle contracts, it moves toward the origin.
Insertion
Types of Body Movements
Flexion
Extension
Rotation
Abduction
Adduction
Circumduction
Dorsiflexion
Plantar flexion
Inversion
Eversion
Supination and pronation
movement that decreases the angle between two body parts
Flexion
movement that increases the angle, or the distance, between two bones or parts of the body
Extension
movement of a bone around a longitudinal axis (ball-and-socket joints)
Rotation
moving the limb away from the midline, or median plane, of the body
Abduction
it is the movement of a limb toward the body midline
Adduction
is a combination of flexion, extension, abduction, and adduction commonly seen in ball-and-socket joints
Circumduction
Lifting the foot so that its superior surface approaches the shin
Dorsiflexion
depressing the foot
Plantar flexion
To invert the foot, turn the sole medially
Inversion
to evert the foot, turn the sole laterally
Eversion
occurs when the forearm rotates laterally so that the palm faces anteriorly and the radius and ulna are parallel
Supination
occurs when the forearm rotates medially so that the palm faces posteriorly
Pronation
Of a group of muscles, the one doing the majority of the work is the ___
prime mover
___ muscle is responsible for the movement of extending knee joint
Quadriceps femoris
__ and ___ in arm flexion and extension
Biceps and triceps
Helper muscles are called ___
synergists
opposing muscles are called ___
antagonists
kissing muscle
orbicularis oris
frontal belly or surprise muscle
occipitofrontalis
smile muscle
zygomaticus major
whistling muscle
buccinator
winking muscle
orbicularis oculi
scowl muscle
corrugator supercilii
snarl muscle
zygomaticus minor
pout muscle
mentalis
grimace muscle
risorius