Ap Exam 4 Part 3

Front 1

What are the Ionotropic Receptors?

Back 1

AMPA

NMDA

Kainate

Front 2

What do AMPA receptors do?

Back 2

They allow sodium in causing a depolarization of the neuron.

Front 3

What do NMDA receptors do?

Back 3

Build longer acting responses over a period of time, while enhancing pain.

Front 4

What are metabotropic receptors?

Back 4

There are some glutamate receptors that fall under this category.

Theses are GPCRs. These are involved in more long term processes.

Front 5

How do we change threshold potential?

Back 5

Polymorphic Na+ channels can each have their own threshold based on how the proteins conform.

Front 6

What does the skeletal muscle function like?

Back 6

Pretty much like a neuron, in terms of the action potential. It is relatively short, uses a neurotransmitter, and action potential is carried through VG Na+ channels.

Front 7

What is the first characteristic that make smooth muscle different from skeletal muscle?

Back 7

It has a lot more variety.

Different Receptors.

Same receptors that produce the opposite effects depending on what tissues they are expressed in. (E.g. ACh in GI is contraction, and in blood vessels it's relaxation.)

Front 8

What is the difference of smooth muscle SR and skeletal muscle SR? What does this do?

Back 8

There are less SR and they are less developed. So, there are less places to store Ca++, so most of the Ca++ must come from the outside sources.

Cardiac muscle also has a very well developed SR.

Front 9

What is the Actin:Myosin Ratio in the Smooth muscle vs the skeletal muscle?

How can this help the smooth muscle?

Back 9

Smooth: 10-20 : 1

Skeletal: 2:1

There is a lower energy usage, and is more energy efficient than smooth muscle because there are less myosin filament that can burn ATP.

Front 10

What are smooth muscles attached to?

Back 10

They are attached to neighboring smooth muscle. Neighboring structures are attached at these dense bodies.

Front 11

What are dense bodies?

Back 11

It is a little knob of connective tissue that connects all the ends of actin filaments and holds them close to somewhere near the cell wall.

These can also action as connection points between adjacent cells.

Front 12

What else can link smooth muscles together?

Back 12

Gap junctions, but not every smooth muscle has gap junctions or even a neighbor.

Front 13

Is smooth muscle faster or skeletal muscle faster?

Back 13

Skeletal muscle is faster, but some smooth muscle can move pretty quickly.

It's not weaker, but it is a little bit slower.

Front 14

What is the latch mechanism in the smooth muscle?

Back 14

This allows for large quantities of hold or tension within smooth muscle units.

The myosin heads don't cross cycle at the same speed as the skeletal myosin heads. They hold on for a little bit longer. This is also an efficient process.

Front 15

What does smooth muscle lack? What really takes its place? What does it look like?

Back 15

It lacks troponin complex, like C, I or T. It binds to calmodulin instead, which looks very similar to Troponin C.

Front 16

What does Calmodulin do?

Back 16

It floats around in the cell. It becomes activated after 4 Ca++ bind to it. It activates MLCK, which phosphorylates myosin light chain.

Front 17

Where do we have control of the activity of thick filaments?

Back 17

We are able to control it from the regulatory light chains on the medial portion of the two heads.

Front 18

How does the myosin filament produce force or be active?

Back 18

Via the phosphorylation of the regulatory light chain.

Front 19

What phosphorylates the Myosin Light Chain?

Back 19

Myosin light chain kinase

This is an enzyme that causes contraction.

Front 20

What takes the phosphate off of the Myosin Light Chain?

Back 20

Myosin Light chain Phosphatase

This is an enzyme that causes relaxation.

Front 21

If there was no Ca++ in the cell, what would happen?

Back 21

Eventually Myosin Light Chain Kinase would simply stop working, and the phosphates would simply just fall off on their own.

Front 22

What increases the activity of myosin light chain phosphatase?

Back 22

PKG

Front 23

Where does PKG come from?

Back 23

NO activating guanylyl cyclase, turning GTP into cGMP and activating PKG.

Front 24

Gap junctions helps smooth muscle act like a what?

Back 24

Like a unit

Front 25

What are the structures of a small artery from outside to inside?

Back 25

Connective tissue(Tunica Adventitia) > muscle fibers(Tunica Media) > Endothelial cells(one layer thick) Tunica Intima

Front 26

What part of the blood vessel plays a big role in what the blood vessel is doing?

Back 26

the endothelial layer

Front 27

How is NO released and what happens once it is released?

Back 27

The endothelial cell senses stress, then activates and eNOS, which converts arginine to NO, which activates guanylyl cyclase, which convert GTP to cGMP, which activates PKG, which inhibits MLCK causing relaxation.

Front 28

What does ACh and Bradykinin do?

Back 28

These are on endothelial cells. It activates Muscarinic ACh-R, the Alpha G protein activates the Ca++ channels on the ER and releases Ca++ from ER to bind to Camodulin to activate eNOS.

Front 29

What are the 3 things that PKG does?

Back 29

Removes phosphate off the Myosin regulatory light chain(inhibition of MLCK(more recognized) or activation of MLCP)

Inhibition of Ca++ influx into the cell

Increase of the SERCA pump

Front 30

What breaks down cGMP to GMP?

Back 30

Phosphodiesterase (PDe)

Front 31

What normally inhibits SERCA pumps?

Back 31

phosphoamban

Front 32

What inhibits PDE5?

Back 32

Sildenafil

Front 33

How does Ca++ get into the cell?

Back 33

Ca++ leak channels

VG Ca++ Channels

Ligand gated Ca++ channels (SR)

Front 34

What happens when an alpha 1 agonist binds?

Back 34

Alpha G protein activates phospholipase C which cuts phosphotydalenositol to DAG and IP3.

IP3 releases stored Ca++ in SR

DAG activates PKC

Front 35

What ion is the cell very permeable to at rest?

Back 35

Na+ and Ca++

Front 36

Ca++ leak channels

Back 36

Play a very important role in how some cells work to keep us alive. It's a little slower.

Front 37

VG Ca++ channels

Back 37

If in smooth muscle we mostly focus on the L-type channels. These are slow to open and slow to close.

Front 38

Ligand gated ca++ channels

Back 38

These can be on the cell wall or on the SR.

Front 39

When you have higher permeability to Na+ or Ca++ what does this mean?

Back 39

It means that you've got a higher resting membrane potential. This is typically found in smooth muscle.

Front 40

Why would you not need an action potential to set off a muscle?

Back 40

There is an inherent leakiness of Ca++ in the tissue, allows a building of contraction.

Front 41

What causes the spikes in slow oscillation waveforms?

Back 41

Neurotransmitters or at the peak of the waveform because you are the closest to threshold.

Front 42

What kind of action potentials can you see in smooth muscle?

Back 42

It can be like a waveform, it can be long with a plateau, it can be short and quick.

Front 43

What is stretch induced relaxation?

Back 43

Bladder filled with urine is stretched, then smooth muscle relaxes in response over a period of time.

Front 44

If you patient has a low BP and hypocalcemia, what would help them out?

Back 44

Giving them Ca++ will help the problems with smooth muscle contraction to help up the blood pressure.