Regulation of the Cardiovascular System Flashcards Preview

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Flashcards in Regulation of the Cardiovascular System Deck (26):
1

7-transmembrane-spanning integral membrane proteins
Extremely important for intracellular signaling throughout body

G protein-coupled receptors (GPCRs)

2


used to treat arrhythmias, hypertension, and for cardioprotection post-MI
many subtypes

b blockers

GPCRs are the most prevalent drug target!

3

used to treat hypertension and heart failure

angiotensin II receptor blockers

GPCRs are the most prevalent drug target!

4

stimulatory G protein

activates adenylate cyclase

ncreases cAMP, activates PIKA

Gs

5

inhibitory G protein

inhibits adenylate cyclase

Decreases cAMP, inhibits PKA

Gi/o

6

activates PLC and PKC

Increases Ca2+ (via IP3R activation & SR Ca2+ release)

Gq

7

Sympathetic stimulation increases inotropy
Little parasympathetic regulation of ______

inotropy

8

Sympathetic stimulation increases inotropy via ________ of 4 proteins involved in EC coupling.

PKA phosphorylation

9

relieves inhibition of SERCA
faster Ca2+ reuptake into SR.
Increases lusitropy.
Increases inotropy by increasing SR Ca2+ load.

PKA phosphorylation of Phospholamban (PLB)

10

_______ stimulation increases inotropy
Little parasympathetic regulation of inotropy

Sympathetic

11

Phosphorylation increases Ca2+ sensitivity,
Increases inotropy by increasing SR Ca2+ release.

PKA phosphorylation of Ryanodine Receptor (RyR)

12

Phosphorylation slows inactivation, increases entry of trigger Ca2+
Increased Ca2+-induced Ca2+ release increases inotropy

PKA phosphorylation of L-type Ca2+ channel (DHPR)

13

decreases Ca2+ sensitivity of troponin C

allows faster dissociation of Ca2+ so faster filling = increased lusitropy (not inotropy)

PKA phosphorylation of Troponin I (TnI)

14

chronotropy

Chronotropic effects are those that change the heart rate.

15

Propranolol blocks β adrenergic receptors ___________

(sympathetic)

16

Atropine blocks muscarinic ACh receptors _________

(parasympathetic)

17

Net inward (depolarizing) current = cardiac “funny current,” If
Promotes excitability and spontaneous action potentials
Highly expressed in sinoatrial myocytes
Activity increased by sympathetic stimulation via cAMP binding

HCNs

18

Contractile proteins in striated muscle are organized in sarcomeres

Actin thin filaments
Myosin thick filaments

19

Small mononucleate cells
No sarcomeres
No troponin complex, no tropomyosin
Ca2+ release from SR not required

Vascular Smooth Muscle Cells (VSMCs)

20

Contraction triggered by mechanical, chemical, or electrical stimuli (APs not required)

Smooth Muscle Contraction: THICK filament regulation

21

Ca2+- CaM binds to ________, to activate it. when activated, phosphorylates the myosin head permits cross bridge cycling in smooth muscle

Myosin Light Chain Kinase (MLCK)

22

MLC dephosphorylated by Myosin Light Chain Phosphatase (MLCP), to ______

halt contraction in smooth muscle

****cAMP (via PKA) inhibits MLCK – causes VSMC relaxation

23

cAMP (via PKA) inhibits MLCK – causes __________

VSMC relaxation

24

Sympathetic stimulation =

VASOCONSTRICTION (usually)

25

Baroreceptor reflex =

SHORT TERM and rapid negative feedback mechanism for sudden changes in blood pressure.

26

cAMP (via PKA) inhibits _________– causes VSMC relaxation

Myosin Light Chain Kinase (MLCK)