High School Biology : Understanding Circulatory Function
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Example Question #11 : Understanding Circulatory Function
Given that the walls of the heart are not uniform, which of the walls would one expect to be thicker or thinner?
The inter-ventricular septum is the thickest
The right atrium is thickest
The left ventricle wall is thinnest
The left ventricle wall is thicker
The right ventricle wall is thicker
The left ventricle wall is thicker
Blood flows back to the heart through the pulmonary veins after being oxygenated in the lungs and re-enters the heart through the left atrium. The blood then passes into the left ventricle, which pumps an enormous volume of blood via the aorta to the rest of the body. This chamber of the heart is under a lot of pressure since the heart must pump blood through the many miles of vessels and arteries; therefore, the left ventricle wall must be thicker to withstand the force of these contractions.
Example Question #225 : Organs And Organ Systems
Which of the following chambers of the heart pumps oxygen-rich blood into the body?
Vena cava
Left ventricle
Left atrium
Right atrium
Right ventricle
Left ventricle
The left ventricle pumps blood into the aorta, through which oxygen-rich blood circulates throughout the body.
Example Question #12 : Understanding Circulatory Function
Which of the following is not a sympathetic effect?
Increased respiratory rate
Pupils dilate
Increase in the heart's force of contraction
Increase in urine production
Increase in heart rate
Increase in urine production
The sympathetic nervous system is a branch of the autonomic nervous system and provides the "fight or flight" response. For this, muscles will need an increased amount of blood, so the heart increases its force of contraction and rate of contraction (heart rate). Additionally, more oxygen needs to be supplied to the muscles, so the respiratory rate also increases. The increase in cardiac output leads to an increase in blood pressure in the sympathetic response.
During the sympathetic response, blood flow is shunted from other organs and sent to the heart and muscles instead. Therefore, digestion and urine production is decreased. Less blood to the kidneys means less urine gets produced.
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