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10 Cards in this Set
- Front
- Back
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The actions of the sympathetic and parasympathetic nervous systems normally _ one another. In other words they are _. If one system contracts a muscle, then the other _ it. The activities of internal _ and _ are therefore regulated by a balance of the two systems. |
oppose / antagonistic / relaxes / glands / muscles |
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The muscle of the heart is known as _ _. It is _, that is, its contraction is initiated from within the muscle itself, rather than by _ _ from outside (_), as is the case with other muscles. |
cardiac muscle. / myogenic, / nervous impulses / (neurogenic), |
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Within the wall of the right atrium of the heart is a distinct group of cells known as the _ _ (_). This bundle of cells can generate _ _ (_ _) on their own and thus set the pace at which the heart _. It is from here that the initial _ for _ originates. |
sinoatrial node (SAN). / electrical signals (action potentials) / contracts. / stimulus / contraction |
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The sinoatrial node has a _ _ of stimulation that determines the beat of the heart. For this reason it is often referred to as the _. |
basic rhythm / pacemaker. |
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The sequence of events that controls the basic heart rate is: (1/3) A wave of _ _ spreads out from the _ _ across both _, causing them to contract. A layer of _-_ _ (_ _) prevents the wave crossing to the _. |
electrical excitation / sinoatrial node / atria, non-conductive tissue (atrioventricular septum) / ventricles. |
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The sequence of events that controls the basic heart rate is: (2/3) The wave of excitation enters a second group of cells called the _ _ (_), which lies between the atria. The atrioventricular node, after a short delay, conveys a wave of _ _ between the ventricles along a series of specialised _ _ called _ _ which collectively make up a structure called _ _ _. |
atrioventricular node (AVN), electrical excitation / muscle fibres / Purkyne tissue / bundle of His. |
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The sequence of events that controls the basic heart rate is: (3/3) The bundle of His conducts the wave through the _ _ to the base of the ventricles, where the bundle branches into smaller fibres of _ _. The wave of excitation is released from the Purkyne tissue causing the _ to _ quickly at the same time, from the bottom of the heart upwards. |
atrioventricular septum / Purkyne tissue. ventricles / contract |
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The atrioventricular septum is a septum of the heart between the _ _ (_) and the _ _ (_). |
right atrium (RA) / left ventricle (LV). |
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Changes to the heart rate are controlled by a region of the _ called the _ _. This has two centres concerned with heart rate: a centre that increases heart rate, which is linked to the _ _ by the _ _ _. a centre that decreases heart rate, which is linked to the _ _ by the _ _ _. |
brain / medulla oblongata. sinoatrial node / sympathetic nervous system. sinoatrial node / parasympathetic nervous system. |
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Which of the two centres is stimulated depends upon the _ _ they receive from two types of receptor, which respond to stimuli of either _ or _ changes in the blood. |
nerve impulses / chemical / pressure |
