Question

Describe the factors that affect cardiac output in a female athlete who is speed skating toward the finish line in an Olympic race.

Answer 1

Cardiac output is measured by considering heart rate and stroke volume.

So the equation for calculating cardiac output is

CO = HR x SV

The number of heartbeats per minute is known as heart rate. The volume of blood ejected from the left ventricle during heart rate is known as stroke volume.

When a heart rate or stroke volume increases, the cardiac output also increases.

Factors that influence the heart rate and stroke volume changes the cardiac output. There are two types of factors influence the heart rate and stroke volume.

Primary factors: Primary factors include blood volume reflexes, autonomic innervation, and hormones

Secondary factors: Secondary factors include extracellular fluid ion concentration, body temperature, emotions, sex, and age.

Case Study: Factors that affect cardiac output in a female athlete who is speed skating toward the finish line in an Olympic race.

To explain the factors influence the cardiac output in the above case study, we need to consider the primary factors as well as secondary factors. The following factors influence the cardiac output in the above-mentioned scenario.

1) Reflexes: Atrial reflex consists of baroreceptors that increases the heart rate. The ventricular reflex increases the end-diastolic volume thereby increases the stroke volume.

2) Autonomic innervation: The medulla oblongata, found in the brain, consists of a cluster of neurons that make up the CAC. Sympathetic fibers beginning in the CAC innervate the SA node, the AV node, and myocardial parts. CAC stimulation causes these fibers to release norepinephrine, thus increasing the heart rate and the strength of contraction.

3) Hormones: When norepinephrine, epinephrine, and acetylcholine are released, the force of myocardial contraction is altered, thus affecting stroke volume. In the above scenario, due to sympathetic stimulation, norepinephrine is released in the myocardium, and norepinephrine and epinephrine are released by the adrenal medullae. Norepinephrine increases heart rate and myocardial contractility. Epinephrine excites the SA node, thereby increasing the rate and strength of myocardial contraction. Clinical correlation: The fight-or-flight response is a physiological and psychological response to hazard or stress. During this automatic involuntary response, the medulla oblongata releases norepinephrine, and the adrenal glands release norepinephrine and epinephrine, resulting in faster heart rate and a stronger heart contraction.

4) Body temperature: Increased body temperature results in an increased heart rate.

5) Emotions: Strong emotions, such as rage, fear, and anxiety, tend to increase heart rate. In the scenario anxiety of the athlete who is skating towards the finish line increases the heart rate, thereby increase in cardiac output.

6) Sex: Heartbeat in females is generally faster than that of males. Female athlete means here gender also influencing the cardiac output.