Cardiovascular lll

Question 1

In patients with chronic HF, what can be used to treat these individuals to inhibit progressive deterioration of cardiac function?

Answer 1

B-blockers prevent sympathetic activation of apoptosis, necrosis, fibrosis, and hypertrophy.

Question 2

Heart muscle cells = myocardial cells. Myocardial cells are striated. What does this mean?

Answer 2

They contain actin filaments and myosin filaments arranged in forms of sarcomeres.

Question 3

How do myocardial cells (heart muscles) contract?

Answer 3

They contract via a sliding filament mechanism.

Question 4

How are myocytes connected?

Answer 4

Via gap junctions

Question 5

Myocytes connected via gap junctions, at the end of each myocardial cell, which permits __________ to be conducted cell to cell.

Answer 5

Electrical impulses

Question 6

Gap junctions stain as ______________________.

Answer 6

Intercalated disks.

Question 7

Myocytes are organized into fibres (groups of myocytes) along with two major organelles. What are they?

Answer 7

Mitochondria for energy and sarcoplasmic reticulum (SR) for calcium (Ca2+ handling).

Question 8

Cardiac action potentials originate in the __________.

Answer 8

SA-node

Question 9

Membrane depolarization causes Ca2+-induced Ca2+ release. Explain this further.

Answer 9

Ca2+ enters myocyte cytoplasm through voltage gated Ca2+ channels, which stimulates the opening of the Ca2+ release channels in the sarcoplasmic reticulum.

Ca2+ form the voltage-gated channels serve as a message for Ca2+ release channels.

Question 10

In order for the heart muscles to relax, the Ca2+ in the cytoplasm must be ____________.

Answer 10

Pumped back into the SR

Question 11

Review the excitation-contraction coupling in cardiac muscle diagram.

Answer 11

Slide 21

Question 12

Explain the 5 steps associated with the “Excitation-Contraction Coupling in Cardiac Muscle”.

Answer 12

1. Ca2+ diffuses from ECF to the cytoplasm.
2. Ca2+ release channels on SR open.
3. Ca2+ released from the SR binds to sarcomere stimulates contraction.
4. Ca2+ -ATPase pumpsCa2+ back into SR
5. Myocardial cell relaxes

Question 13

Muscle fibres are made-up of thin _______ filaments and thick ________ filaments.

Answer 13

Actin, myosin

Question 14

Cells in the muscle are arranged into long, rod-shaped subunits called _________.

Answer 14

Myofibrils

Question 15

The myofibril rods that compose muscles have a distinct strained pattern of __________________.

Answer 15

Alternating light and dark bands.

Question 16

The _____ are proteins in the muscle that act was anchors for thin protein filaments, consisting of a protein called actin.

Answer 16

Z-discs