smartbook assignment 4
What muscle type(s) would you expect to find in the cardiovascular system?
Cardiac & smooth
The motor end plate has large numbers of ______ receptors.
acetylcholine
In a neuromuscular junction, the enzyme _____ breaks down acetylcholine.
acetylcholinesterase
When the triceps brachii extends the elbow, its action is considered to be that of which of the following?
agonist
Match the type of primary action to its correct description.
agonist-prime mover antagonist-opposes the agonist synergist-Assists the agonist
Skeletal muscles are grouped according to their primary actions into which of the following three types?
agonists synergists antagonists
Match the type of primary action to its best description.
agonists-a muscle that contracts to produce a particular movement synergists-a muscle that either contributes to tension close to the insertion or stabilizes the point of origin antagonists-a muscle that stretches when the agonist contracts
The orbicularis oris muscle is named for its ______.
arrangement of muscle fascicles and body location
After breaking your arm, you have a cast on it for three months. When the cast is removed, your arm looks much smaller than it did before. The process called ______ caused this to happen.
atrophy
The mechanism of contraction in smooth muscle involves a calcium-binding protein called ______.
calmodulin
A muscle fiber is what level of organization in the body?
cellular
The type of tetany in which a muscle cell is stimulated so frequently that it is not allowed to relax at all between stimuli is called ______ tetany
complete
The shortening of muscle cells is called _______, a property that allows muscle cells to cause body movement.
contraction
Which type of muscle has widespread muscle fibers over a broad area that collect themselves onto a common attachment site?
convergent muscles
Sarcoplasm is another term for skeletal muscle ______.
cytoplasm
Muscle tissue demonstrates the property of _____ when it is done contracting and returns to its resting length.
elasticity
The synaptic knob of the neuron is a(n) ______ of an axon.
expanded tip
True or false: After diffusing across the synaptic cleft, ACh binds to receptors on the synaptic knob.
false
True or false: Parallel muscles have low endurance but are very strong.
false
In a normally functioning muscle, the inability to contract and produce tension is called muscle
fatigue
Overall, as aging progresses, muscle strength and endurance are impaired, and the individual has a tendency to _______ quickly
fatigue
A skeletal muscle cell is also called a muscle
fiber
Smooth muscle is composed of short cells that have a ______ shape.
fusiform
Many parallel muscles are cylindrical with an expanded central region called a ______.
gaster or body
An increase in muscle fiber number is called ______.
hyperplasia
An increase in muscle fiber size is called
hypertrophy
An increase in the number of mitochondria can be observed in ______.
hypertrophy
Athletes have more defined muscles than non-athletes even while at rest because they have ______ motor units contracting all the time.
more
in a motor unit, a single ______ neuron typically controls numerous muscle fibers in a muscle
motor
Upon release from the synaptic knob, acetylcholine attaches to receptors on the ______.
motor end plate
A motor unit is composed of a single ______ and all of the muscle fibers it controls.
motor neuron
Muscle tissue is distributed almost everywhere in the body; it is responsible for the _____ of materials within and throughout the body.
movement
Which category is utilized in the naming of the extensor radialis longus muscle?
muscle action
Which category is utilized in the naming of the deltoid muscle?
muscle shape
What is the force generated when a skeletal muscle is stimulated to contract called?
muscle tension
After the age of 30, the number of ______ in existing muscle fibers decreases.
myofibrils
Which of the following is considered a circular muscle?
orbicularis oris
Which of the following is an example of a convergent muscle?
pectoralis major
Which four of the following characterize the different patterns of fascicle arrangement?
pennate convergent circular parallel
Match the pattern of fascicle arrangement with its best description. Instructions
pennate-these fascicles are arranged at an oblique angle to the tendon convergent-have widespread muscle fibers over a broad area that meet on a common attachment site circular-concentrically arranged fibers around an opening parallel-often associated with cylindrical muscles with a central body tendon
As you struggle to twist open a jar, more motor units are called into action until you finally generate enough force to open it. This is an example of ______.
recruitment
The motor end plate is a specialized region of the ______.
sarcolemma
A contracting skeletal muscle fiber typically shortens as all of its ______ shorten in length.
sarcomeres
At the end of muscle contraction, calcium ions are moved back into the _____ reticulum by ATP-driven ion pumps.
sarcoplasmic
According to the sliding filament theory, when a muscle contracts, thick and thin filaments _______ According to the sliding filament theory, when a muscle contracts, thick and thin filaments _____ shortens
slide; sarcomere
The _______ filament theory explains how muscle fibers shorten during contraction.
sliding
Smooth muscle contraction is ______ resistant to _______ , and usually sustained for an extended period of time.
slow; fatigue
A circular muscle is also called a(n) ______.
sphincter
A "step-wise" increase in the force of contraction of a single muscle fiber or single motor unit due to repeated stimulation is called
summation
Usually during axial muscle contraction, the more moveable muscle attachment, the ______ attachment is pulled toward the less moveable muscle attachment.
superior
The narrow space separating the synaptic knob and the motor end plate is called the ______.
synaptic cleft
A nerve impulse travels through an axon to its ______.
synaptic knob
The expanded tip of an axon is called a ______.
synaptic knob
The motor end plate has folds and indentations to increase the membrane surface area adjacent to the ______.
synaptic knob
The force generated when a skeletal muscle is stimulated to contract is muscle
tension
As a result of ACh stimulation, calcium ions are released from the ______ of the sarcoplasmic reticulum.
terminal cisternae
As you sit there reading this your muscles, even your relaxed ones are not completely relaxed and soft. This is because they have some background tension called resting muscle ______.
tone
Smooth muscle cells retains their mitotic ability.
true
A single contraction and relaxation of a muscle fiber is referred to as a muscle
twitch
Match the type of pennate muscle with its best description.
unipennate-all muscle fibers are on one side of the tendon (extensor digitorum) bipennate-usually has muscle fibers on both sides of the tendon (rectus femoris) multipennate-has branches of the tendon within the muscle (deltoid)
You have hooked a frog calf muscle up to a myogram that records muscle tension. You notice that when you stimulate the muscle to contract, then stimulate it again before it can fully relax, the amount of tension generated in the second contraction is greater than the first contraction. This phenomenon is called ______.
wave summation
Identify the components of the NMJ in the picture. Instructions
A - moves into the axonal terminal;calcium ions (synaptic vesicle) B - moves into the sarcoplasm;sodium ions (synaptic knob) C - moves across the synaptic gap;acetylcholine (synaptic cleft) D - moves out of the sarcoplasm;potassium ions (sarcolemma) E-sarcoplasm
The ACh receptors on the motor end plate are ______ ion channels.
chemically gated
The enzyme acetylcholinesterase resides in the synaptic
cleft
Common intramuscular injection sites include the _____ region.
deltoid
What are some terms used in naming muscles according to shape?
deltoid rhomboid trapezius
Acetylcholine moves across the synaptic cleft by ______.
diffusion
Bundles of muscle fibers, termed ______, lie parallel to each other within a muscle.
fascicles
In a transverse section of a muscle, you can see that each skeletal muscle is actually composed of many ________ , which are bundles of muscle fibers.
fascicles
If a muscle cell is stimulated to contract, allowed to partially relax, then stimulated again, its force of contraction the second time will be ______.
higher
When a nerve impulse reaches the end of an axon of a neuromuscular junction, calcium flows ______ the synaptic knob.
into
Smooth muscle contraction is under ______ control.
involuntary
In the picture of the adult holding the baby in a steady or constant position, the type of contraction that is represented is an (man holding baby)
isometric
Curare is a plant toxin used by indigenous people of South America in their blowguns to paralyze prey. What is a feasible mechanism of action for this drug?
it binds to and blocks ACh receptors on the motor end plate
Match each stage of a muscle twitch with the amount of tension generated.
latent period- there is no tension contraction period-tension increases relaxation period-tension decreases
Each muscle fiber is controlled by one ______ neuron.
motor
Synaptic knob, motor end plate, and synaptic cleft are parts of a ______.
neuromuscular junction
When an appendicular muscle is contracting, the less moveable muscle attachment is usually the ______ attachment.
proximal
As you hold a barbell and begin to flex your arm in a curl, your biceps brachii slowly lifts the weight by using more and more motor units. This phenomenon, which increases the strength of the contraction, is referred to as
recruitment
What are some terms used in naming muscles according to orientation of fascicles?
rectus oblique
After stimulation of ACh receptors, a muscle impulse spreads quickly along the _______ and into the muscle fiber along T-tubules.
sarcolemma
Cardiac muscle cells are ______ and thicker than skeletal muscle cells, and they have only ______ nuclei.
shorter; 1-2
Approximately 40-50% of your body weight is _____ muscle.
skeletal
Attached to the skeleton and surrounding the openings of the urinary and gastrointestinal traces are locations of ______ muscle.
skeletal
A neuromuscular junction contains a(n) ______.
synaptic knob, motor end plate, synaptic cleft
Place the events that occur at a neuromuscular junction in order.
1. nerve signal arrives at synaptic knob 2. calcium enters and binds synaptic vesicle 3. ACh is released via exocytosis into the synaptic cleft 4. ACh binds receptors on the motor end plate
Identify the components of a sarcomere in the picture provided. Instructions
A I band B A band C M line D Z disc
Identify each type of muscle contraction pictured.
A-isometric B-concentric isotonic C-eccentric isotonic
According to the sliding filament theory, the length of the ______ band remains constant, but the ______ zone disappears.
A; H
Acetylcholinesterase in the synaptic cleft is needed so that ______ will not continuously stimulate the cell to contract.
ACh
The arrival of a nerve impulse at the synaptic knob of a motor neuron causes synaptic vesicles to release _____ into the synaptic cleft.
Acetylcholine
Muscle cells are said to have what characteristic because they can respond to stimulation from the nervous system?
Excitability
Which can cause muscle fatigue?
Na+ or K+ imbalances insufficient Ca2+ build up of intracellular Pi
The cytoplasm of a skeletal muscle cell has a specific name and is known as
Sarcoplasm
Intramuscular injections are commonly used to administer medication because of which of the following characteristics?
a rich blood supply
Match the letter with its muscle fascicle arrangement.
a-convergent b-circular c-parallel d-pennate
Cardiac muscle cells form Y-shaped branches and join to adjacent muscle cells at junctions called ______ discs
intercalated
Muscle fibers contain cylindrical structures called myofibrils, which are composed of ______.
myofilaments
Termination of the nerve impulse at an NMJ results in the passive sliding of ______ back to their original state.
myofilaments
Smooth muscle cells have a unique protein called ______ light-chain kinase.
myosin
