Lecture 18 Smooth and Cardiac Muscle Tissue Flashcards Preview

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Flashcards in Lecture 18 Smooth and Cardiac Muscle Tissue Deck (26)
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1
Q

Characteristics of Cardiac Muscle Tissue

A
Single mononucleated cells
Centrally positioned nuclei
Sarcomeric arrangement 
Cells communicate via gap junctions (intercalated discs)
Cells not directly innervated
2
Q

T-tubules of Cardiac Muscle Tissue

A

Not as extensive as in skeletal muscle
Each t-tubule interacts with one cisterna (rather than two in skeletal muscle) - diad rather than triad
Located at the level of the Z lines

3
Q

Composition of Intercalated disks

A

Macula Adherentes (desmosomes)
Fascia Adherentes
Gap Junctions

4
Q

Macula Adherentes of Intercalated Disks

A

Link intermediate filaments (desmin) of adjoining cardiac muscle cells
Part of transverse component

5
Q

Fascia Adherentes of Intercalated Disks

A

Anchor actin filaments of sarcomeres

Part of transverse component

6
Q

Gap Junctions of Intercalated Disks

A

Part of longitudinal component

7
Q

Atrial Natriuretic Peptides (ANPs) are secreted by:

A

Cardiac muscle cells in atria

8
Q

What are the functions of ANPs?

A

Regulate fluid electrolyte balance

Relax vascular smooth muscle - reduces blood volume and pressure

9
Q

ANP is stored as a ______ in secretory vesicles

A

Prohormone

10
Q

The release of ANP is stimulated by:

A

Atrial stretch - results in cleavage of prohormone

11
Q

Synonyms of Smooth Muscle Tissue

A

Involuntary

Visceral

12
Q

Characteristics of Smooth Muscle Tissue

A
Single mononucleated cells w/ central nuclei 
No sarcomeric arrangement
Innervated via ANS or enteric system 
Do not respond "all or none"
Connected via gap junctions
13
Q

In smooth muscle cells, Actin and Myosin bundles are incorporated into a _______ arrangement

A

Meshwork

Found throughout cytoplasm except in nuclear area

14
Q

What are the functions of Dense Bodies?

A

Anchor actin filaments to each other and to cell membrane

Communicate force of contraction to cytoskeleton and cell membrane

15
Q

Dense bodies contain:

A

alpha-actinin

16
Q

Dense bodies are interconnected by:

A

specific type of desmin

17
Q

Where are dense bodies found?

A

In cytoplasm and in the cell membrane

18
Q

True or False:

Smooth Muscle cells have t-tubules and an extensive SR

A

False

Smooth muscle cells do NOT have t-tubules or extensive SR

19
Q

Smooth muscle cells depend on extracellular ______ for contraction

A

Calcium

20
Q

In smooth muscle cells, pinocytotic vesicles:

A

may transport calcium ions from extracellular fluids to sarcoplasmic reticulum

21
Q

Caveolae and Lipid Rafts in Smooth muscle cells

A

Permanent depressions of the cell membrane that are involved in fluid and electrolyte transport

22
Q

Caveolae and lipid rafts are preceded by membrane lipid rafts composed of:

A

Cholesterol and Sphingolipids

23
Q

_______ binds to the cholesterol in the lipid rafts and initiates the formation of caveolae

A

Caveolin

24
Q

True or False:

Innervation of smooth muscle may either facilitate or inhibit contraction of the muscle cells.

A

True

25
Q

Types of smooth muscle neurotransmitter receptors

A

Adrenergic and muscarinic receptors - linked to G-proteins

Nicotinic cholinergic receptors - cation channel

26
Q

True or False:

Smooth muscle sheets of most major organs are highly innervated.

A

False

They are poorly innervated - excitation is spread through numerous gap junctions