Lecture 17: Cardiac And Smooth Muscle Tissue Flashcards Preview

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Flashcards in Lecture 17: Cardiac And Smooth Muscle Tissue Deck (5):

Describe the characteristics of cardiac muscle tissue

- Single mononucleated cells
- Centrally positioned nuclei
- Sarcomeric arrangement
- Cells communicate via gap junctions:
-- Intercalated discs
- Cells not directly innervated


Describe the cardiac muscle T-tubule system

- Not as extensive as in skeletal muscle
- Each T-tubule interacts with one cisterna (rather than two as in skeletal muscle)
-- Forms a diad rather than a triad.
-- Diads are located at the level of the Z-lines.


Describe the composition of intercalated discs in cardiac muscle tissue

- Macula adherentes (desmosomes)
-- Link intermediate filaments (desmin) of adjoining cardiac muscle cells
-- Part of transverse component
- Fascia adherentes
-- Anchor actin filaments of sarcomeres
-- Part of transverse component
- Gap junctions:
-- Part of longitudinal component

- See Slides 6-9


What are ANPs?

Atrial Natriuretic Peptides:

- Secreted by cardiac muscle cells in atria
- Regulate fluid electrolyte balance
- Relax vascular smooth muscle:
-- Reduces blood volume and pressure
- Stored as prohormone in secretory vesicles
- Release is stimulated by atrial stretch.
-- Results in cleavage of prohormone



Resume at slide 11