Endocrine, Circulatory, and Respiratory Systems

Bio Lab Work Sheet on the Endocrine Circulatory and Respiratory Systems

The endocrine system, the respiratory system, and the cardiovascular system are interrelated body systems because they depend on each other. Each of these systems is made up of numerous organs or body parts and related hormones that enhance its functionality. For instance, this lab report shows that the endocrine system has sixteen organs along with hormones that are secreted by them while the cardiovascular system also has sixteen parts. The respiratory system has twelve organs that perform respiration functions in the body. This lab report discusses the functions of insulin and glucagon in glucose metabolism, explains and compares the pulmonary pathway and the systemic pathway, and explains how epinephrine and norepinephrine alter the respiratory and heart rate during exercise.

Table 1: Endocrine System

Endocrine system

Table 2: Cardiovascular System

Cardiovascular System

Endocrine System: Functions of Insulin and Glucagon in Glucose Metabolism

Insulin and glucagon are two hormones secreted by the pancreas. Both of them influence glucose metabolism in the body. The ratio of insulin to glucagon regulates blood glucose, depending on the hormone that dominates the other. For instance, when one is engaged in vigorous activity, the sympathetic nervous system is stimulated, leading to inhibition of insulin secretion (McArdle, Katch, & Katch, 2006). Also, during stress, sympathetic input to the pancreas increases, thus inhibiting secretion of insulin. Consequently, gluconeogenesis is stimulated, leading to the provision of extra glucose energy for the nervous system and skeletal muscles (McArdle, Katch, & Katch, 2006).
Insulin influences glucose metabolism by enhancing uptake of glucose by all cells in all tissues except the brain in various ways. First, insulin increases the transport of glucose to most of insulin-sensitive cells. Usually, adipose tissue and skeletal muscles require insulin to facilitate glucose uptake when one is at rest. On the other hand, exercising skeletal muscles do not require insulin to enhance glucose uptake because GLUT-4 transporters activate without any insulin stimulation to increase glucose uptake when muscles react (McArdle, Katch, & Katch, 2006). Secondly, insulin enhances the utilization and storage of glucose by cells because it activates enzymes that boost glucose utilization and those that enhance synthesis of fat. It also activates enzymes that enhance fat synthesis. Therefore, insulin stimulates glycolysis, gluconeogenesis and lypolysis, making metabolism move towards anabolism. Whenever a person consumes more glucose than his or her body requires for metabolism, the body converts the excess into glycogen or fatty acids. Insulin also enhances utilization of amino acids and promotes fat synthesis to utilize amino acids and glucose by converting them into triacyglycerols.

On the other hand, glucagon, an antagonist hormone to insulin, is secreted by the pancreas. Glucagon stimulates the increase of blood glucose. It, therefore, stimulates liver glycogenolysis and gluconeogenesis, and catabolism of lipids. Therefore, glucagon secretion in large quantities leads to catabolic activity. Glucagon stimulates glycogenolysis and gluconeogenesis to increase glucose output, which is required for metabolism. The hormone also stimulates a catabolic effect on adipose tissue of the body (McArdle, Katch, & Katch, 2006).

Insulin stimulates anabolic reactions increase the amount of stored carbohydrates, fats, and proteins. The expected metabolic outcome is production of lower blood glucose and storage of energy. Conversely, glucagon stimulates catabolic reactions, leading to the breakdown of glycogen, protein and fats (Norman, Dean, & Henry, 2015). Consequently, blood glucose levels are elevated, leading to metabolism and use of energy.

Cardiovascular System: The Pulmonary Pathway versus the Systemic Pathway

Blood flows in two distinct pathways in the body. The first way is the pulmonary pathway, which involves the transportation of deoxygenated blood to the lungs for oxygenation. The other pathway, through which blood flows in the body, is the systemic pathway. It involves the transportation of oxygenated blood from the lungs to other parts of the body such as tissues and organs for use. Therefore, the blood that flows in the pulmonary pathway is deoxygenated, and it is delivered to the lungs. The blood that flows in the systemic pathways leaves the lungs, and it flows in the heart to be delivered to the body tissues because it is full of oxygen. After use by body tissues, the blood is returned to the heart for oxygenation, and cycle goes on.

Table 3: Pulmonary Pathway versus the Systemic Pathway

Pulmonary Pathway versus the Systemic Pathway

Body Experiences: How Epinephrine and Norepinephrine alter Respiratory and Heart Rate during Exercise

Whenever human beings are subjected to stressors, they react in different, but universal ways. For instance, some people show fright on their faces while others become sad. Some people can start breathing faster while their hearts beat at a faster rate if they are exposed to some situations. Similarly, some stressors such as exercise, fright and emotional stress lead to secretion of hormones, which direct the way an individual reacts to the situation. The rates of breathing and heartbeat are different when one is sorrowful from when he or she is joyous. Hormones like epinephrine and norepinephrine are produced when one is subjected to stressful events. The adrenal gland is responsible for the secretion of epinephrine and norepinephrine, which affect the heart rate and the breathing rate (Bouchard, Blair, & Haskell). Following is an explanation of how the hormones produced by adrenal could play a role in altering the respiratory and heart rate during exercise.

Epinephrine and norepinephrine are responsible for the regulation of energy utilization and mobilization during exercise. Epinephrine and norepinephrine are made and secreted by the adrenal gland. When sympathetic nerve terminals are activated, during exercise, they lead to plasma spillover (Bouchard, Blair, & Haskell). The concentration of plasma epinephrine and norepinephrine increases as exercise intensifies. The reason for this is the intensity of work relative to maximal aerobic capacity. Peripheral factors related to the working muscles and commands from the brain lead to these elevations. Epinephrine stimulates fuel mobilization while norepinephrine is attributed to partitioning of blood flow, increased contractility of heart muscles, and blood pressure intensification. Therefore, the sympathetic nervous system is activated by the hypothalamus in response to release epinephrine and norepinephrine into the blood stream. The heart rate increases while the respiratory rate increases too, leading to faster breathing. The two hormones, epinephrine and norepinephrine, increase blood flow to the muscles of the body by increasing heart rate and the force of contraction (Buckworth & Dishman, 2002). The rate of respiration increases because the body has to provide sufficient energy to be used by muscles that are engaged in exercise. Consequently, the rate of heartbeat increases significantly while the breathing rate increases because the body needs to replace the oxygen that has been used up in respiration.