Ap Exam 4 Part 4

Front 1

What receptors have a lot of cross talk because they are similar?

Back 1

Histamine and ACh and bradykinin

Front 2

What is the reason why people with HTN and diabetes are more likely to have a bad stroke?

Back 2

Because their endothelial layer is not able to cope and dilate as needed.

Front 3

What's endothelial dependent vascular relaxation?

Back 3

This is where we need a working endothelial cell to relax the smooth muscle.

ACh, Bradykinin, or Histamine binds activating Ca++ release from the ER, which binds to Calmodulin, and activating eNOS.

Front 4

What's endothelial independent vascular relaxation?

Back 4

This is where there are NO donors that are independent of the endothelial cell release NO to relax the smooth muscle.

Front 5

What happens when you have HTN or uncontrolled diabetes?

Back 5

Problem with producing NO from the endothelial cells.

NO donors don't typically float around in the blood, so it's hard for vessels to cope if something bad happens.

Front 6

Where is PDE found?

Back 6

They tend of be present in pts with smooth muscle and in lungs.

Front 7

What is sildenafil(viagra) used to block?

Back 7

PDE5

Front 8

What ions influxing can produce action poentials?

Back 8

Na+ and Ca++

Front 9

What happens when the Alpha 1 receptor is activated?

Back 9

Alpha G protein activates phospholipase C, this clips Phosphatydalinositol into Dag and IP3.

DAG- activates PKC

IP3- releases stored Ca++ that binds to Calmodulin. This activates MLCK.

Front 10

What is cardiac muscle?

Back 10

It's a hybrid of smooth muscle and skeletal muscle.

Front 11

What ion dictates the strength of contraction in the heart?

Back 11

Ca++

Front 12

What is Ca++ induced Ca++ release?

(CI-CR)

Back 12

There are Voltage sensors that are built into the SR. Depolarization opens these up.

Front 13

What does the setup of the cardiac muscle look like?

Back 13

It's very orderly. With thick filaments being sandwiched between thin filaments. Like skeletal muscle.

Front 14

How does a contraction work in heart muscle?

Back 14

Ca++ binds to troponin C, which takes tropomyosin off active sites. Myosin heads attach and contraction occurs.

Front 15

How much comes into the cardiac cell from SR and Extracellularly? What about what goes out of the cell?

Back 15

SR - 80%

Extracellular - 20%

Same

Front 16

What happens in phase 0 in slow nodal tissue?

Back 16

Fast tissue:

A steep depolarization occurs, where fast Na+ channels open up. Fast action potential. Initial upstroke.

Slow Tissue:

Less steep. Some of the top is encompassed in phase 2.

Front 17

What happens in phase 1 in slow nodal tissue?

Back 17

Fast Ca++ channels called T-type channels open up. K+ channels open

Does not exist is slow tissue

Front 18

What happens in phase 2 in slow nodal tissue?

Back 18

Fast tissue:

Slow Ca++ current through L-type channels open up. T-type Ca++ channels close.

Slow Tissue:

Encompasses the tip of the action potential.

Front 19

What happens in phase 3 in slow nodal tissue?

Back 19

Ca++ L-type channels close.

Increasing permeability to K+ to help reset after an action potential.

Front 20

What happens in phase 4 in slow nodal tissue?

Back 20

Membrane potential is low, like -80-90.

(Show Na+ permeability is very low)

There is still a slight slope.

(Due to an increase in Na+ permeability and decrease in K+ permeability.)

Na+/K+ ATPase is working.

Front 21

What is fast tissue?

Back 21

Ventricular tissue

Front 22

What is slow tissue?

Back 22

Nodal tissue

Front 23

What is the differences between slow tissue from fast?

Back 23

Resting membrane potential is -55 mV.

The upslope is less steep.

There is no phase 1

Large drop in K+ permeability and a steeper incline of Na+(in phase 0)

Front 24

What is the threshold potential for Nodal tissue?

Back 24

-40 mV, this will correspond to the point before the action potential occurs.

Front 25

What ion is more important in the length and slope of phase 4?

Back 25

Primary: Na+

Secondary: Ca++

Front 26

What is the start point of phase 4 in the slow tissue?

Back 26

Resting membrane potential

Front 27

What is the end point of phase 4 in the slow tissue?

Back 27

Threshold potential

Front 28

What is the ideal heart rate in a 70 year old male?

Back 28

72 beats per minute, so the time between beats is less than 1 second.

Front 29

What happens if you lower resting membrane potential? How does this occur? By what receptor?

Back 29

more time between heart beats

increase K+ efflux

Muscarinic ACh receptor

Front 30

What if we decreased the permeability of phase 4 to Na+ or Ca++?

Back 30

There would be more of a delay before an action potential. The slope would be less steep.

Front 31

In nodal tissue what kind of receptor is unique to it?

Back 31

Beta adrenergic receptor

This is coupled to a Na+ channel and when it is activated it increases nodal tissue permeability to Na+.

Front 32

What is the absolute refractory period?

Back 32

Period of time where another action potential cannot be elicited from the tissue.

Front 33

What is the relative refractory period?

Back 33

It's the tail end of phase 3. We might be able to elicit an action potential but it will not be a normal one.

Front 34

What amount of Ca++ being pumped out will be pumped out through the Na+/Ca++ exchanger?

Back 34

15%

It is a high capacity, low affinity pump

Front 35

What amount of Ca++ being pumped out will be pumped out through the Ca++ ATPase?

Back 35

5%

This is also called the plasma ATPase

It is a low capacity, high affinity pump

Front 36

What typically inhibits the SERCA pump?

Back 36

Phospholamban

Front 37

What inhibits phospholamban?

Back 37

PKA, it allows for the heart to reset faster and have a higher heart rate.