The Heart 3

Question 1

Steps of Skeletal Muscle Contraction

Answer 1

1. Action Potential from CNS
2. AP reaches NM Juction, Ca++ channels open (INFLUX)
3. Ca ++ influx, causes Ach endocytosis
4. Ach Binds receptors at post synaptic membrane
5. Na+ rushes into cell, Depolarization
6. Depolarization enters T-Tubules –> SR releases Calcium
7. Contraction lil’bitch!!!!!

Question 2

Explain Calcium Induced Calcium Release

Answer 2

Ryanodine Receptors - are triggered to release SR^calcium into the myoplasm, when myoplasmic Calcium increased during action potential

Question 3

Steps of Cardiac Muscle Contraction

Answer 3

1. Action Potential from Purkinje Fibers
2. AP propagates along sarcolema and in t-tubules opening their Ca2+ channels (20% of total Ca++)
3. Ca ++ influx, bind SR, and Ryanodine Receptors - are triggered to release SR^calcium into the myoplasm
4. Contraction lil’bitch!!!! (80% total Ca++)

Question 4

Dystrophin Glycoprotein Complex (DGC) Functions?

Connects to?

Mutations can lead to?

Answer 4

1) Membrane Stability
2) Force Transduction
3) Organization of Membrane (found at Z-Line)

Actin
Mutations - Muscular Dystrophy, Dilated Cardiomyophathies

Question 5

The more Ca++ the ____________

Recall how is Ca2++ removed from the myoplasm (2)

Answer 5

Stronger the Contraction/AP

1) SR Ca2++ Pump (atpase) (Ca –» SR)
2) Na+/Ca++ Exchanger (1CA (o) 3Na (i))

Question 6

Divisions of the NS (top to bottom)

pneumonic

Answer 6

Central (spinal/brain) Peripheral (body)
P –> somatic & autonomic
A–> sympathetic & parasympathetic

CP to San Antonio, SP

Question 7

Define:

1. Chronotropic

2. Inotrophic

Answer 7

1. Chronotropic - Relating to Heart Rate

2. Inotrophic - Relating to Force of Contraction

Question 8

The [PSNS (via Vagus n.), SNS] has an effect of what parts of the heart?

Answer 8

PS - SA & AV nodes, Atrium

S - SA & AV nodes, Atrium, VENTRICLE

Question 9

Name the Neurotransmitters of the PNS, and SNS, and their associated receptors.

What other hormone binds to B1 Receptors?

Answer 9

PS - Acetylcholine (Muscarinic Receptors) MUSS-Karin- ic
S - Norepinephrine (B1 Adrenergic Receptor) ADD-RINN- Ergic - PAM

Epinepherine also binds B1 - Adrenal Medulla

Question 10

Sympathetic Stimulation Produces (6)

Answer 10

Increased HR (effect on SA node)
Increased AP velocity at AV node
Increased contractile force
Increase SR release of Ca++
Decrease troponin (Ca++ sensitivity)
Decrease AP, and contraction duration

Question 11

Sympathetic Stimulation works when ___1___ activates ___2___, which activates ____3____ which converts ____4___, to ____5____, which activates ____6____, which (+) effects 7, 8, 9, 10 increasing their function!

note* 9, 10 - shorten action potential & contraction

Answer 11

1. Norepinepherine, epinepherine
2. B1 - Adrenergic Receptors
3. Adenylyl Cyclase 4. ATP 5. cAMP
4. PKA
5. Ca++ (L) 8. Pacemaker Channel (Na/K) 9. K+(rectifier)
6. cAMP Dependent Cl- Channel

Question 12

Parasympathetic Stimulation Produces (3)

Answer 12

Decreased HR (effect on SA node)
Decreased AP velocity at AV node
Increased contractile force - Atria (doesn't reach ventricle)

Question 13

Parasympathetic Stimulation works when ___1___ activates a ___2___, which (IN)activates ____3____ stopping production of ____4___, inactivating ____5____, which (-) effects 6, &7 decreasing their function. The activated G-Protien however directly activates ___8___

note* 8 activation + 6,7 inhibition, causes slowing of HR

Answer 13

1. Acetylcholine
2. Muscarinic Receptor
3. Adenylyl Cyclase
4. cAMP
5. PKA
6. Ca++ (L) 7. Pacemaker Channel (Na/K)
7. K+ (non-rectifier channels)

Question 14

Name the intracellular enzyme that degrades cAMP

Answer 14

Phosphodiesterase