Muscles Flashcards
Name the 3 types of muscle tissue.
smooth cardiac skeletal
Where is smooth muscle found?
walls of visceral organs (except heart) eye muscles airways
What attaches muscle to bone?
tendons
What attaches bone to bone?
ligaments
What provides the energy to power muscles?
ATP
Muscle contraction results from what?
the sliding together of thick myosin & thin actin filaments within the muscle cell
Which muscle filament is thick?
myosin
Which muscle filament is thin?
actin
Do skeletal muscles act alone or in pairs/groups?
pairs/groups
What do we call the skeletal muscle that is most responsible for a given movement?
agonist or prime mover
What are the muscles that work in cooperation with the agonist/prime mover called?
synergists
What is the muscle that produces the opposite movement of the agonist/prime mover called?
antagonist
Muscles respond to what?
nerve impulses
Where do muscles receive nerve impulses?
neuromuscular junctions
What is secreted at neuromuscular junctions?
neurotransmitters
Explain what causes stimulation of a muscle fiber?
Nerve impulse travels from nerve to muscle cell at neuromuscular junction neurotransmitter is secreted & is diffused across the junction neurotransmitter stimulates muscle fiber
What neurotransmitter do motor neurons use to control skeletal muscle?
acetylcholine
Muscles working under anaerobic conditions produce what?
lactic acid
What chemical causes muscle fatigue?
lactic acid
What is the end of a muscle that is attached to a moving part called?
insertion
What is the end of a muscle that is attached to a fixed point called?
origin
What are the functional units of muscle fibers called?
sarcomeres
In a lever system, what is the lever?
a bar
What is a fulcrum?
the fixed point in a lever system
What is the applied force in a lever system called?
effort
In a lever system, what is the load?
some form of resistance
What is an example of a fulcrum in the body?
joints
What is an example of a lever in the body?
a bone
What is an example of an effort in the body?
muscle contraction
What is an example of a load in the body?
the weight of the bone itself along with overlying tissues
What is the contractile response of a single muscle fiber to a muscle impulse?
muscle twitch
What are the important ions in the nervous system?
sodium & potassium
What is it called when many action potentials are triggered in a motor neuron, resulting in a contraction of increasing strength?
a sustained contraction
Slow twitch (red fibers) muscle fibers
dependent on O2 and are fatigue resistant.
Fast Twitch (white fibers) muscle fibers
anaerobic, contract and fatigue rapidly; found in hands and eyes
Describe muscle tone
results from a continuous state of partial contraction; important in maintaining your posture
Describe Isometric Contractions
Contract with no movement; example is pushing against something
Describe Isotonic Contractions
contraction with muscle shortening, example is lifting a weight
What is all or none response?
muscle will respond completely or not at all; stimulus must surpass threshold to illicit response, response will be a complete contraction or none at all
Are voluntary muscles controlled by the somatic or autonomic nervous system?
somatic
Are involuntary muscles controlled by the somatic or autonomic nervous system?
autonomic
Is skeletal muscle voluntary or involuntary?
voluntary
Is smooth muscle voluntary or involuntary?
involuntary
Is cardiac muscle voluntary or involuntary?
involuntary
List the skeletal muscle structure in order from the outside to the inside.
Aponeurosis (covers groups of muscles) Fascia (covers single muscle) Epimysium Perimysium Fascicles Endomysium Muscle Fibers
List structure of muscle fibers from the outside to the inside.
Sarcolemma Myofibrils Sarcomeres Actin & Myosin
Which filament is thin?
actin
Which filament is thick?
myosin
What is the contracting, functioning unit of a muscle fiber?
sarcomeres
Sarcomeres have what 4 qualities?
A bands I bands H zones Z lines
List the steps to muscle contraction.
Muscle is at rest (polarized)
Stimulus from nerve (threshold stimulus)
Depolarization (Na+ channels open/Na+ flows in - action potential travels along)
Repolarization (K channels open/K flows out - membrane returns to negative resting potential/polarized state)
What is metabolism?
All chemical processes occuring in the body
What does ATP stand for?
adenosine triphosphate
Why is ATP important to muscles?
It is required to make muscles work.
What is oxidation?
the loss of electrons
What is reduction?
a gain of electrons
Where does cellular respiration occur?
in the mitochondria
What are the steps of cellular respiration?
glycolysis
(pyruvic acid)
/ \
O2 present lack of O2
/ / \
transition reaction alcohol lactic acid
(acetyl coenzyme A)
/
Krebs Cycle
/
electrons picked up by NAD & FAD
/
electron transport chain (32 ATP made - 36 total)
What is the equation for cellular respiration?
C6H12O6 + O2 → CO2 + H2O + ATP
Define homeostasis.
the ability to maintain a constant internal environment regardless of external conditions
List order of steps of homeostatic control.
stimulus (↑ or ↓ of body temp) is received by receptors (temp. sensitive receptors in skin)
input is sent via afferent pathway to control center (brain)
control center decides if stimulus crosses threshold
(if so) control center sends output via the efferent pathway to effector (sweat glands/skeletal muscles)
response (sweat evaporation & ↓ temp/shivering & ↑ temp) causes end of stimulus
How many cranial, spinal nerves are there?
12
How many spinal nerves are there total?
31
How many cervical, spinal nerves are there?
8
How many thoracic, spinal nerves are there?
12
How many lumbar, spinal nerves are there?
5
How many sacral, spinal nerves are there?
5
How many coxygeal, spinal nerves are there?
1
