Acknowledgement of Academic Responsibility
Answers to assignment questions must be original; that is, you must write them all yourself. You can base your
answers on information in the course textbook or other sources, but if you use sources other than the textbook,
you must cite them appropriately.
Plagiarism is a form of academic misconduct that has serious consequences. It is your responsibility to read and
understand the statement on Academic Integrity in the Student Manual and the Student Academic Misconduct
Policy in the AU undergraduate Calendar. If plagiarism is detected, and if an investigation concludes that you
must rewrite the assignment, then your assignment grade will be reduced by 20 marks.
“By filling in my name and ID number below, I acknowledge my responsibility to academic integrity and
confirm that none of the wording in my answers has been copied or plagiarized in any way from any
source.”
Student’s name: Colombe kanku
Student's AU ID number: 3418750
NOTE: The assignment will not be marked if it is submitted without the above two lines filled in.
Assignment 1 :: Biology 235: Human Anatomy and Physiology 1
, Assignment 1
Weight: 5%
Minimum Pass Grade: 50%
Each question is worth 10 marks.
1. Maintenance of calcium ion homeostasis is critical to neurological, cardiac and skeletal muscle function.
Consider the roles of two hormones involved in the regulation of the concentration of calcium ions in the
blood. Parathyroid hormone increases the concentration of calcium ions in the blood, while calcitonin
decreases the concentration. Based on this information predict the body’s response to restore calcium
balance if a person swallowed 100 antacid tablets made of a calcium compound in 10 minutes. Include in
your answer the definition of homeostasis, the type of feedback loop involved and all of the components of
a feedback loop.
Homeostasis occurs when the body achieve equilibrium in the body’s internal environment due to
constant interaction of the body’s many regulatory processes. Homeostasis is a dynamic condition
and the balance can shift along a narrow window that is compatible with life. Homeostasis is
constantly being disrupted and rely on the responses of the body to return it to normal. Although
there are many regulatory system, most often it is the nervous and endocrine system that are
involved in returning the body to normal either individually or as a team. The body uses feedback
system to maintain homeostasis. A feedback system is a cycle of events in which the status of a body
condition is monitored, evaluated, changed, monitored reevaluated until equilibrium is achieved. The
main components of feedback system are receptor, control center and effector. A stimulus will cause
a change to the controlled condition, the receptor will notice this and alert the control center, the
control center will tell the effector what to do, the effector will elicit a response. These components
are what maintain equilibrium.
In this case, the level of calcium ion in blood normally stays between a narrow range to maintain
homeostasis. Multiple negative feedbacks systems will be involved in the situation described above.
Including hormones such as calcitonin, parathyroid hormone and calcitriol to maintain the balance of
calcium ion level in blood. The function of calcitonin is to decrease blood calcium ion level. The
function of parathyroid hormone is to increase blood calcium ion level. Lastly, the function of
calcitriol is to decrease calcium absorption from dietary sources.
After the person swallows 100 antacid tablets the person’s blood calcium level would rise
significantly in 10 minutes. One negative feedback loop that would be involved is: high level of
calcium ion in blood will stimulates parafollicular cells (receptors) in the thyroid gland (control
center) to secrete calcitonin (the output). Calcitonin inhibits activity of osteoclasts (effector), speeds
blood calcium ion uptake by bone (effector) and accelerates calcium ions deposition into bones. This
results in calcium promoting bone formation and decrease blood calcium ion level.
Another negative feedback loop is involved: high level of calcium ion in blood will be detected by
parathyroid gland cells (receptor) and consequently lower parathyroid hormone (the output)
produced by parathyroid gland. Osteoclasts (effector) activities decreases and kidney will release
calcium in urine. Calcitonin which is released by the thyroid gland decreases blood calcium levels
when they are too high. These actions occur as a response to calcitonin and will return the blood
Assignment 1 :: Biology 235: Human Anatomy and Physiology 2
Answers to assignment questions must be original; that is, you must write them all yourself. You can base your
answers on information in the course textbook or other sources, but if you use sources other than the textbook,
you must cite them appropriately.
Plagiarism is a form of academic misconduct that has serious consequences. It is your responsibility to read and
understand the statement on Academic Integrity in the Student Manual and the Student Academic Misconduct
Policy in the AU undergraduate Calendar. If plagiarism is detected, and if an investigation concludes that you
must rewrite the assignment, then your assignment grade will be reduced by 20 marks.
“By filling in my name and ID number below, I acknowledge my responsibility to academic integrity and
confirm that none of the wording in my answers has been copied or plagiarized in any way from any
source.”
Student’s name: Colombe kanku
Student's AU ID number: 3418750
NOTE: The assignment will not be marked if it is submitted without the above two lines filled in.
Assignment 1 :: Biology 235: Human Anatomy and Physiology 1
, Assignment 1
Weight: 5%
Minimum Pass Grade: 50%
Each question is worth 10 marks.
1. Maintenance of calcium ion homeostasis is critical to neurological, cardiac and skeletal muscle function.
Consider the roles of two hormones involved in the regulation of the concentration of calcium ions in the
blood. Parathyroid hormone increases the concentration of calcium ions in the blood, while calcitonin
decreases the concentration. Based on this information predict the body’s response to restore calcium
balance if a person swallowed 100 antacid tablets made of a calcium compound in 10 minutes. Include in
your answer the definition of homeostasis, the type of feedback loop involved and all of the components of
a feedback loop.
Homeostasis occurs when the body achieve equilibrium in the body’s internal environment due to
constant interaction of the body’s many regulatory processes. Homeostasis is a dynamic condition
and the balance can shift along a narrow window that is compatible with life. Homeostasis is
constantly being disrupted and rely on the responses of the body to return it to normal. Although
there are many regulatory system, most often it is the nervous and endocrine system that are
involved in returning the body to normal either individually or as a team. The body uses feedback
system to maintain homeostasis. A feedback system is a cycle of events in which the status of a body
condition is monitored, evaluated, changed, monitored reevaluated until equilibrium is achieved. The
main components of feedback system are receptor, control center and effector. A stimulus will cause
a change to the controlled condition, the receptor will notice this and alert the control center, the
control center will tell the effector what to do, the effector will elicit a response. These components
are what maintain equilibrium.
In this case, the level of calcium ion in blood normally stays between a narrow range to maintain
homeostasis. Multiple negative feedbacks systems will be involved in the situation described above.
Including hormones such as calcitonin, parathyroid hormone and calcitriol to maintain the balance of
calcium ion level in blood. The function of calcitonin is to decrease blood calcium ion level. The
function of parathyroid hormone is to increase blood calcium ion level. Lastly, the function of
calcitriol is to decrease calcium absorption from dietary sources.
After the person swallows 100 antacid tablets the person’s blood calcium level would rise
significantly in 10 minutes. One negative feedback loop that would be involved is: high level of
calcium ion in blood will stimulates parafollicular cells (receptors) in the thyroid gland (control
center) to secrete calcitonin (the output). Calcitonin inhibits activity of osteoclasts (effector), speeds
blood calcium ion uptake by bone (effector) and accelerates calcium ions deposition into bones. This
results in calcium promoting bone formation and decrease blood calcium ion level.
Another negative feedback loop is involved: high level of calcium ion in blood will be detected by
parathyroid gland cells (receptor) and consequently lower parathyroid hormone (the output)
produced by parathyroid gland. Osteoclasts (effector) activities decreases and kidney will release
calcium in urine. Calcitonin which is released by the thyroid gland decreases blood calcium levels
when they are too high. These actions occur as a response to calcitonin and will return the blood
Assignment 1 :: Biology 235: Human Anatomy and Physiology 2
