Test 3 Info Flashcards
Smooth muscle contraction is under ______ control of the nervous system
involuntary
Single unit muscle cells contract _____.
together
in unison
Thin filaments in smooth muscle cells contain the proteins ______ (2)
Actin
Tropomyosin
Caveolae
Invaginations of the plasma membrane
Increase the surface area of the sarcolemma of smooth muscle
Dense plaque
Points where intermediate filaments are anchored to the inner surface of the sarcolemma of smooth muscle
Varicosity
A vesicle (bead) that stores norepinepherine at the terminal branches of ganglionic sympathetic neurons
The z discs that anchor the sarcomere on either end in skeletal muscle are ____ from smooth muscle cells
absent
Do smooth muscle cells have transverse tubules?
No
Smooth muscle cells have a single, centrally located
nuleus
Examples of locations for smooth muscle:
1) In the wall of the small intestine
2) Around blood vessels
3) In the wall of the uterus
In smooth muscle, thin filaments are attached to ____ by elements of the cytoskeleton
dense bodies
Smooth muscle contraction is ___, resistant to ___ and usually sustained for ______ periods of time.
slow
fatigue
extended
Locations for multiunit smooth muscle:
1) Arrector pili muscles
2) Iris of the eye
The sarcolemma of smooth muscle cells has small invaginations called ____
caveolae
During contration of smooth muscle, ____ binds to calcium and activates myosin light chain kinase
calmodulin
The mechanism of contraction in smooth muscle involves a calcium-binding protein called _____
calmodulin
Autonomic motor neurons that control smooth muscle contraction have bulbous swellings called ____ that contain synaptic vesicles.
varicosities
Ohm’s Law
Voltage = Current * Resistance Current = Voltage/Resistance Resistance = Current/Voltage
_____ occurs when the inside of the cell becomes more positive than the resting membrane potential
Depolarization
What 2 things must happen in order for a chemical signal to change the membrane potential of a neuron?
1) Change in # of open ion channels
2) Change in ion flow across the membrane
Compare properties of neuron to electrical currents:
1) Charged particles
2) Voltage
3) Resistance
4) Current
1) Ions
2) Membrane potential
3) Plasma membrane
4) Flow of ions through ion channels
The opposition to the movement of electrical charge is known as ____
resistance
Voltage is a measure of relative _____ _____.
Potential energy
2 basic causes of the development of the resting membrane potential
1) Na+ leak channels
2) K+ leak channels
The resting membrane potential is measured in _____
millivolts (mV)
In the initial segment, an action potential is generated if the membrane potential reaches the ___ ___
threshold value
Current
Movement of charged particles
What channels open and in what order do they open to develop an action potential?
1) Voltage gated Na+
2) Voltage gated K+
What type of channels are essential for the generation of an action potential?
Voltage gated channels
Graded potential
Temporary change in membrane potential which lasts only as long as the stimulus that causes it and can vary in size
Opening of what 2 types of channels would likely lead to hyperpolarization of a neuron?
1) voltage gated potassium channel
2) chemically gated chloride channel
What 2 things would follow after threshold voltage is reached due to sodium ions entering through a voltage gated Na+ channel?
1) Membrane potential would reverse (become positive)
2) More voltage gated sodium channels would open
What is the typical resting membrane potential of a neuron?
-70 mV
What is a central function of neuron physiology?
Creating electrical current
Transmitting electrical current
3 Cranial meninges (from deepest to superficial)
1) Pia mater
2) Arachnoid mater
3) Dura mater
Cerebral aqueduct
connects the third and fourth ventricles through the midbrain
Functions of the Cerebrospinal Fluid
1) Environmental stability
2) Buoyancy
3) Protection
Arachnoid villi
.
Cavities within the brain are called
ventricles
Which of the meninges is the strongest?
Dura mater