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The ventricles are filled with cerebrospinal fluid (CSF) which bathes and cushions the brain and spinal cord within their bony confines. CSF is produced by modified ependymal cells of the choroid plexus found in all components of the ventricular system except for the cerebral aqueduct and the posterior and anterior horns of the lateral ventricles.
Type A receptors are activated by wall tension, which occurs via atrial contraction during ventricular diastole. Type B receptors are activated by wall stretch, which occurs via atrial filling during ventricular systole. [1] In the right atrium, the stretch receptors occur at the junction of the venae cavae.
The atrioventricular node delays impulses by approximately 0.09s. This delay in the cardiac pulse is extremely important: It ensures that the atria have ejected their blood into the ventricles first before the ventricles contract. [9] This also protects the ventricles from excessively fast rate response to atrial arrhythmias (see below). [10]
The bundle of His (BH) [1]: 58 or His bundle (HB) [1]: 232 (/ h ɪ s / "hiss" [2]) is a collection of heart muscle cells specialized for electrical conduction.As part of the electrical conduction system of the heart, it transmits the electrical impulses from the atrioventricular node (located between the atria and the ventricles) to the point of the apex of the fascicular branches via the ...
(2) The atrial systole contractions are incomplete and thus do not contract to the extent that would block flow from the veins through the atria into the ventricles. During atrial systole, blood not only empties from the atria to the ventricles, but blood continues to flow uninterrupted from the veins right through the atria into the ventricles ...
There is an increased flow of blood to the lungs through both the ventricular and atrial components of the defect. In addition, the abnormal atrio-ventricular valve invariably leaks, so that when the ventricles contract, blood flows not only forwards to the body and the lungs, but also backwards into the atria. The back-pressure effect on the ...
The Bainbridge reflex (or Bainbridge effect or atrial reflex) is a cardiovascular reflex causing an increase in heart rate in response to increased stretching of the wall of the right atrium and/or the inferior vena cava as a result of increased venous filling (i.e., increased preload).
[2] various other inputs from the hypothalamus, thalamus, and cerebral cortex. [4] The cardiovascular centre affects changes to the heart rate by sending a nerve impulse to the cardiac pacemaker via two sets of nerves: sympathetic fibres, part of the autonomic nervous system, to make heart rate faster.