Page 425 - Atlas of Histology with Functional Correlations

Purkinje Fibers

Larger than cardiac fibers with more glycogen and lighter staining
Part of the conduction system of the heart
Located beneath the endocardium on either side of the interventricular
septum

Branch throughout the myocardium and deliver stimuli via gap junctions to
the rest of the heart

Atrial Natriuretic Hormone (ANH)

Certain atrial cells contain granules with ANH
Released when atrial wall is stretched
Decreases blood pressure by inhibiting renin and aldosterone release
Influences kidneys to lose more sodium and water to decrease blood volume

and pressure

Review Questions

QUESTIONS

In the following multiple-choice questions, choose the letter corresponding
to the one best answer.

1. Which part of the heart conduction system branches and stimulates the

contraction of ventricular musculature?

A. Sinoatrial node

B. Purkinje fibers

C. Internodal pathway

D. Atrioventricular bundle

E. Atrioventricular node

2. Purkinje fibers are recognized histologically by:

A. containing more contractile filaments.

B. their location deep in the heart musculature.

C. being larger and thicker than the cardiac cells.

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