Nerve/muscles Flashcards
The primary functional cell of the nervous system is called a
Neuron
What is the term used to describe the electrical signal used during cell communication?
action potential
What are sarcomeres
contractile units of muscles
When the cell membane is at RMP is the voltage-gated sodium (Na+) channel open or closed
closed
When do actin-myosin cross bridges form
when calcium ions (Ca2+) bind to troponin
In skeletal muscles the muscle will lengthen or shorten during _______ contractions
isotonic
A skeletal muscle fibre action potential is initiated after:
Acetylcholine causes the opening of sodium (Na+) channels.
a whole Nerve surrounds
fascicles
fascicles are surrounded by
neurons (cells)
in a neuron they include ____ to help the process of communication
axon
What are the two types of neuronal communication
neuron to neuron
neuron to muscle
Neurons communicate using signals in the form _______ and _______
Bioelectricity and neurontransmitters
bioelctricity in the neuron passes its bioelectricity onto other…
neurons (neuron to neuron) or muscles (neuron to muscles) to communicate
Bioelectricity is called an
action potential
action potential is the propagation of a change in ____ (movement of ions) across the cell membrane down an axon
voltage
The structure of the input zone of a neuron is called
Dendrites
Structure of an output zone in a neuron is called
synaptic terminals
What are the three main subtypes of muscle
Cardiac, smooth, skeletal
Where is smooth muscle found
Gastrointestinal tract
What type of control is the cardiac and smooth muscles
Autonomic (involuntary)
What type of control is the skeletal muscle
somatic (voluntary)
What is a sarcolemma
cell membrane that surrounds each myofibre - acts as a barrier
what is a sarcomere comprised of
filaments (myofilaments) - act as a contractile unit
What do mitochondria do in a muscle cell
create ATP (energy for muscle contraction - energy unit
What are Transverse tubules (t-tubules) do in a myofibre
they are extensions of the sarcolemma that dive deep into the muscle - regulatory unit
What are they two types of myofilaments sarcomere is made up of
Actin and mysosin
Actin is a thick or thin filament
thin
Myosin is a thick or thin filament
thick
What is sarcomeres appearance like?
Striated (stripes) = striated muscle
Hypertrophied mean to
use a muscle- making it larger
What are two ways to hypertrophied a muscle
- build more sacromeres
- create new myofibres
atrophied means to
lose a muscle e.g. sarcomeres disappear
Transverse tubules are extensions of the sarcolemma and only occur on the surface of the muscle
False - occur both inside an outside
What is a motor unit
Comprised of a motor neuron and all the muscle fibres that it innervates
where are motor neurons located
Motor neurons cell bodies (somas) are in the ventral (front/anterior) part of the spinal cord
number of motot units activated ate any one times can be varied to change the amount of force produced what is this called?
recruitment
Why do we need skeletal muscles system (what 3 functions)
- movement
- posture - holding skeleton up so you don’t fall
- Thermoregulation- reducing heat
How many myofibers can be innervated by one axon
one
- one myofiber to one axon
one axon can innervated how many myofibres
one axon to multple myofibers
- one ‘a’ to mm
action potential is achieved because movement of ions across the cell membrane create ……
an ion gradient for more ion movement
What charged ions attract in a electrical gradient
opposite charges attract
True ore false ions require a gradient to move down electrical gradient
true
What is it called when ionic charges are balanced?
equilibrium
What ions move down their chemical (concentration) gradient - down the hill
Na+ and K+
When a chemical concentration is balanced they are what
at equilibrium
what charged ions does a gradient exist to allow it to diffuse into the cell
positively
What blocks the ions from diffusing through the cell membrane
Phospholipid bilayer
True or false because of the phospholipid bilayer ions need channels to diffuse through the cell membrane
true
What are the 4 phases of the action potential
- resting membrane (RMP)
- depolarisation
- repolarisation
- Hyperpolarisation
True or false at rest the RMP (voltage) is at -60mV
FALSE - the RMP is at -70mV
What is the definition of voltage
The difference in charge across the membrane
What cause the RPM to be at -70mV
Na+/K+-ATPase pumps ions against their electrochemical gradient
True or false at RPM there is high Na+ concentration outside the cell
TRUE
True or false at RMP there is high K+ concentration inside the cell
true
True or false voltage gated ion channels are OPEN when the RMP of cell is -70mV
false they are closed
What voltage threshold do voltage gated Na+ channels open at
-60mV
What voltage threshold do voltage gated K+ channels open at
+30mV
True or false = at RPM outside of the cell is + and inside -
True
T/F
At depolarisation Na+ enters cell so inside becomes + and outside -
true
Na+ will continue to enter the cell until the membrane potential reach what voltage?
+30mV
at repolarisation voltage is +30mV so what voltage- gated channels are open and which are closed
Na+ = closed @ +30mV
K+ = open @ +30mV
K+ can leave the cell down its electrochemical gradient because of the opening of the voltage- gated K+ channels
true
T/F: Hyperpolarisation
K+ leaves cell so becomes -
true
In hyperpolarisation: Voltage gated K+ channels remain open until a thresehold of …
-40mV
K+ will continue to leave cell at hyperpolarisation until membrane potential reaches
-80mV
What does refractory period mean
not able to generate another action potential during this period
The axon function is to
send action potential down the axon (over a distance)
t/f
at +30mV voltage- gated Na+ channels close and voltage-gated K+ channels open
TRUE
What is the voltage of threshold
-60mV
When voltage reaches -60mV (threshold) voltage gated __ channels will ____
Na+ will open
What is the difference between Incomplete tetanus and complete tetanus
Incomplete= muscle fibre producing maximum tension during rapid cycles of contraction and relaxation
Complete = relaxation phase is eliminated by higher frequency stimuli (no time for Ca to be removed)
What is Tetanic contraction
One fibre
• Forced produced by a fibre at its maximum
which type of contraction develops tension within a skeletal muscle
isometric, concentric, eccentric
following postural hypotension, blood pressure is restored by
increasing heart rate and vadocontriction
