Cpps415 Part 4

Front 1

Cardiomyocytes

Back 1

Striated muscle, single nucleated, form functional syncytium.

Connected to each other by intercalated disks.

Front 2

Basic contractile unit of cardiomyocyte?

Back 2

Sarcomere: region betwren 2 Z-line

Contain thick (myosin) and thin (actin) filaments.

Front 3

Which in charge of passive tension of the heart

Back 3

Titin proteins: which connect myosin filament to the Z-lines.

Front 4

Thick filament

Back 4

Thick (myosin) filaments are connected to the Z-line by titin proteins. Surrounded by 6 thin filaments.

Composed of hundreds of myosin molecule. Each myosin has 2 heads that contain ATPases to interact with actin. Myosin light chain is responsible for myosin phosphorylation by myosin light chain kinases

Front 5

Thin filaments

Back 5

Composed of actin, tropomyosin, and troponin.

Each tropomyosin is associated with 7 actin molecules.

Tropin has 3 subunits: troponin-T (attach the tropomyosin), troponin-C (binding site for Calcium), troponin-I (inhibit myosin binding to actin).

Front 6

Markers for cardiac infarction

Back 6

Troponin T and I

Front 7

Excitation-contraction coupling

Back 7

6. Removal of Ca2+ from troponin C stops cross-bridging

Front 8

Cross-brigde?

Back 8

When myosin heads bind to actin

Front 9

Factors increasing inotropy

Back 9

1. Increase Ca2+ influx via phosphorylation of L-type Ca2+ channels by cAMP.

2. Increase Ca2+ release from SR via phosphorylation by both cAMP and IP3.

3. Increase affinity of troponin-C to Ca2+.

4. Increase myosin-ATPase activity via phosphorylation of myosin light chain.

5. Increased SERCA pump activity by inhibiting phospholamban via cAMP phosphorylation. => more Ca2+ intake onto SR => more Ca2+ release from SR.

6. Inhibit Ca2+ efflux by inhibiting Ca2+ pump and Na-Ca exchanger.

Front 10

What inhibit Na-K pump

Back 10

Digitalis and cardiac glycosides

Front 11

How to reduce troponin-C affinity for Ca2+

Back 11

Increase troponin-I via phosphorylation => increase the rate of Ca2+ disocciate from troponin-C

Front 12

Vascular smooth muscle

Back 12

Many caveolae, undeveloped SR, unorganized actin and myosin.

Electrically connected via gap junctions.

Front 13

Smooth muscle contraction. What inhibit contraction

Back 13

Increase in intracellular Ca2+ induces calmodulin and activates myosin light chain kinase to phosphorylate myosin light chains.

cAMP inhibit myosin light chain kinase => inhibit contraction

Front 14

Pathways determine muscle tone

Back 14

1. IP3 via Gq phospholipase C: increase Ca2+ release from SR => contraction

2. cAMP via adenyl cyclase: inhibit myosin light chain kinase => relaxation.

3. cGMP via Nitric oxide activation of gyanyl cyclase => diffused from endothelial cells => relaxation

Front 15

Primary site for cardiovascular regulation?

Back 15

Medulla

Front 16

Nucleus tractus solitarius (NTS)

Back 16

Located within the medulla. Receieve afferent nerves from chemoreceptors, baroreceptors, stretch receptors.

Provide inhibitory interneurons to sympathetic efferent nerves and excitatory interneurons to parasympathetic nerves.

=> increase NTS activity increases parasympathetic and decreases sympathetic.

Front 17

Types of receptor in the heart, vessel, sympathetic terminal

Back 17

Heart: B1 >> B2 and a1; Muscarinic M2

Sympathetic terminal: a2 (bind NE, inhibit), Muscarinic M2.

Vessels: a1 >> a2 and B1; B2 M2(relax)

Front 18

Baroreceptors (location, innervation, firing activity) => relationship to sympathetic

Back 18

Carotid sinus and aortic arch. Both nerves related to NTS.

Baroreceptors fire rhythmically and increase firing when arterial pressure increases. Decrease firing when arterial pressure drops.

=> increase firing increases NTS activity => increase inhibition of sympathetic => sympathetic less active.

=> decrease firing when blood pressure drop decreases NTS activity => decrease inhibition of sympathetic => sympathetic more active.

Front 19

Chemoreceptors

Back 19

Inhibitory nerve travel to the NTS.

_Peripheral chemoreceptors: sense O2, CO2 and pH.

.found in external carotid arteries and aortic arch.

.increase firing when O2 drops, pH decreases (acidosis) and CO2 rises => NTS decreases=> promote sympathetic.

_Central chemoreceptors:

Found in the medulla. Increase firing when CO2 increases, pH drops (acidosis). Indirect to O2 drops.

Front 20

What causes increased blood volume during pregnancy

Back 20

Estrogen mediated activation of renin-angiotensin-aldosterone system

Front 21

NE and Epi affinity

Back 21

Epi: B1 B2 >> a1 a2

NE: B1 and a1 >> B2 a2

Front 22

RAS system

Back 22