-
-
multipolar, bipolar, unipolar
Name three types of neurons
-
they latch on and grow around the axon. they help insulate and are coated with myelin
What are Schwann cells?
-
NODES OF RANVIER
What are the gaps between Schwann cells called?
-
I = V / R
aka
current = potential ÷ resistance
current- the movement of charged particles
potential- the difference between two charges
resistance- the opposition to current flow
What is Ohm's Law?
-
volts
potential is measured in what unit?
-
polarized, negative inside
- If cells have potential, they are....
- (name term, and describe their internal charge)
-
Positive outside
Negative inside
cells are like the teacher. They are _____ on the outside and _______ on the inside.
-
Potassium is on the inside, and it LEAKS out. When K leaks out it's making the cell a POSITIVE OUTSIDE and a NEGATIVE INSIDE
When looking at the neuron model, what direction does K+ move?
-
K goes back & forth until it reaches EQUILIBRIUM. Then it reaches RESTING MEMBRANE POTENTIAL (thus making it polarized)
K+ leaks out, but closer look shows K is leaving and entering, it does this until it reaches ________. Then it reaches _______________, thus making it polarized
-
Potential
When a cell is polarized this means it has ________.
-
- cell must have slightly positive outside, and slightly negative inside
- Excitability Summary - Steps
- - What is required for a cell to react to stimulation?
-
Potassium (K) leaks out of cell until this slightly + outside and slightly - inside is achieved, this ready state is called RESTING POTENTIAL
How does a cell get a + outside and a - inside?
-
when stimulated, sodium (Na+) gates OPEN. This makes cell less NEGATIVE on the inside AKA MORE POSITIVE on the inside.
When cell is chemically stimulated, sodium gates do what? This makes the cell less _______ on the inside (+ or _?)
-
if sodium gate sticks open, threshold gets met, then DEPOLARIZATION happens , thus allowing ACTION POTENTIAL
If enough sodium (Na+) enters cell and cell reaches "threshold" the gate sticks and cell completely _________ , thus causing _________________ to occur at that location
-
REPOLARIZATION
After action potential, K+ leaves the cell. This period is called?
-
POTASSIUM! it POLARIZES!
SOOOoooo what leaks of a cell?
-
SODIUM!! it DEpolarizes!!
SOOOOooooo what leaks into a cell?
-
ATP!
It returns electrolytes to where they belong
- What is required for this sodium potassium pump to work?
- What is it's main function?
-
Refractory period (the amount of time it takes for an excitable membrane to be ready for a second stimulus once it returns to its resting state following excitation)
What is the period where nerve impulse is non-responsive
-
goes away from the origin (spreads like a fire down axon)
What direction does transmission go?
-
myelin sheath
What makes nerve transmission go faster?
-
NO! Synapses
Are neurons directly connected? What is this meeting place called?
-
NEUROTRANSMITTERS!
When the action potential is travelling down the axon and it reaches the end (of the axon) what is released?
-
a chemical key which needs a receptor
What are neurotransmitters?
-
EPSP Excitatory Post Synaptic Potential
or
IPSP Inhibitory Post Synaptic Potential
What are the two type of responses to neurotransmitters?
-
excites = TOWARD the threshold
AKA
depolarization followed by polarization
EPSP (eg Sodium Potassium pump)
AKA excitatory = TOWARD the threshold
-
inhibitory = AWAY from threshold
AKA
polarization followed by depolarization
IPSP (eg Chloride Cl- gate)
AKA inhibitory = AWAY from threshold
-
the Chief INHIBITORY neurotransmitter via Chloride gate
What are GABA receptors known as?
-
This is process of both EPSP and IPSP working
If they fire at the same time, they cancel each other out.
What is summation?
-
EPSP, many of them!
What type of neurotransmitter response is needed for action potential?
-
neuromuscular junctions are 1:1 (don't need many bumps)
1 motor neuron controls many muscle cells (fibers)
-
ACETYLCHOLINE
What does the motor neuron release when impulse reaches the neuromuscular junction?
-
Endomysium
perimysium
Epimysium
-
the lined up proteins are the cause of stripes on the muscle fiber
-
Sarcomere, it is made of Actin (thin filament) and Myosin (thick filament)
What is the basic unit of a muscle cell?
-
the Myosin pulls Actin toward the center of sarcomere.
Note: neither mysoin nor actin gets shorter, but by sliding the overall unit (sarcomere) gets shorter
- How does sarcomere get shorter? (contracts)
- *hint what pulls on what?
-
ATP!!! ATP is required in order to "reload"
Myosin Loves Actin. Myosin heads pulls on actin. What makes the myosin let go?
-
Troponin & Tropomyosin.
- What guards the actin? (aka prevents myosin heads from latching on)
- *hint they make muscle relaxed
-
CALCIUM! Specifically Calcium binds with Troponin
So Troponin & Tropomyosin are wrapped around actin..... what helps push Tropomyosin away so that actin is no longer guarded, allowing muscle to contract?
-
the sarcoplasmic reticulum. Transverse (T) tubules
Where is Calcium stored in muscle? What is name of network that allows it to flow throughout muscle?
-
Cholinesterase. It allows muscle to recover
So if acetylcholine is the neurotransmitter that initiates muscle contraction, what is name of neurotransmitter that breaks it down?
-
1. Myoglobin- protein carries small amt of oxygen.
Function: to store excess oxygen within the muscle cell, to help buffer supply during periods of excessive demand. (Even with help from the myoglobin, it's often that muscles have to resort to anaerobic metabolism under strenuous exercise, during which lactic acid is built up and released into the blood stream).
2. Lactic Acid- used in sprints/bursts of energy when oxygen is not readily available
3. Creatine- stores ATP, can quickly hand it over for use
What are the 3 ways of energy for contraction?
-
ISOTONIC
When muscle gets shorter (but not tighter) what kind of contraction is this?
-
ISOMETRIC
When muscle gets tighter (but not shorter) what kind of contraction is this?
-
Isotonic vs isometric diagram
-
Tetanus
When neurons are firing too rapidly before they can recover is called?
-
Tone
When muscle is firm but not contracting is? It's continuous and passive partial contraction of muscles
-
atonia (loss of strength)
If you cut the nerve, muscle will be soft as jelly
-
NO. It is involuntary
Also:
No stripes
found in hollow organ walls (intestines)
Can smooth muscle stimulate itself?
-
NO. Involuntary. Also it is automatic, the nerves don't make it contract, therefore no control over speed of contractions
-ALWAYS needs oxygen (aerobic)
-NO TENANUS possible!! Can't lock up
-Can depolarize themselves
Can cardiac muscle stimulate itself?
|
|
