BSC 2346 Module 10 Lab Worksheet: Endocrine System.Introduction
This week’s lab will focus on the major endocrine glands and the hormones
... [Show More] they
secrete.
Objectives
Objectives for this week’s lab include: 1) Identify the location of the major
endocrine glands, 2) Map out the hormonal secretion of and influence of the major
endocrine glands, and 3) Identify the role of major endocrine hormones, and 4)
Describe the negative feedback mechanism to maintain homeostasis.
Overview
The endocrine system regulates the body’s actions and metabolic activity through
the use of chemical messengers called hormones. Hormones, produced by
endocrine glands, are secreted directly into the blood stream, travel throughout the
body and influence the actions and activity of various cells. It’s a complex
mechanism of how a hormone directly influences a cell but a cell needs to have a
specific receptor on its plasma membrane to bind a specific hormone. If a cell has a
specific hormone, it is referred to as a target cell.
Each hormone will have a unique and specific influence on cellular activity that may
include: reproduction activities, growth and development, electrolyte, water and
nutrient balance in the blood, metabolism and even influence our immune system.
Once a cell binds a hormone through its receptor, the response and impact of that
hormone can vary greatly. Some hormones have an almost instantaneous effect on
that cell (such as epinephrine, aka- adrenaline) to an effect that can last days to even
months (such as growth hormone).
Hormonal levels are maintained by a negative feedback mechanism. As hormonal
levels rise in the blood and affect the target cells, it causes a negative feedback loop
to initiate the inhibition of further hormone production and secretion from its
endocrine gland. Through this mechanism, hormonal homeostasis is maintained
within a very narrow range and is vital because any imbalances to hormonal levels
can cause drastic changes in the body’s physiology and can cause conditions such as,
type 2 diabetes and hypothyroidism.
Materials
Endocrine gland models
Pre-Lab Evaluation Questions
The pre-lab evaluation questions must be answered prior to lab and demonstrated
to your lab instructor. You must read through the assigned chapter readings, lab
introduction, objectives, overview and procedure to answer these questions.
Please cite your work for any reference source you utilize in answering these
questions.
1. In your own words, briefly describe how the endocrine system helps to
maintain homeostasis within the body.
The endocrine system is a process that relate with the glands and
their hormone to regulate specific target in our body. Endocrine help
maintain homeostasis when need more energy or resting, play the role for
sexual function, signal the bone and tissue for growing, maintain the
heartbeat, sugar level, calcium level, fluid level in body.
2. Explain how the thyroid gland and the parathyroid gland help to maintain
homeostasis of blood calcium levels?
The thyroid gland also secretes a hormone called calcitonin that is
produced by the parafollicular cells. Calcitonin is released in response to a
rise in blood calcium levels. It appears to have a function in decreasing blood
calcium concentrations by:
• Inhibiting the activity of osteoclasts
• Increasing osteoblastic activity
• Decreasing calcium absorption in the intestines
• Increasing calcium loss in the urine
The parathyroid glands are tiny, round structures usually found
embedded in the posterior surface of the thyroid gland. These epithelial cells
produce and secrete the parathyroid hormone (PTH), the major hormone
involved in the regulation of blood calcium levels, in response to low blood
calcium levels by
Stimulating osteoclasts to release of calcium from the bones into the
interstitial fluid.
Inhibit the activity of osteoblasts
Increased reabsorption of calcium (and magnesium) in the kidney
tubules from the urine filtrate
3. The thyroid gland also produces two hormones that influence our body’s
metabolism. What are those two hormones and the difference between
them? What element/molecule is vital to provide proper function to these
two hormones? In general and overall, what effect do these two hormones
have on the body’s function?
The thyroid hormones, T3(triiodothyronine) and T4 (thyroxine), are
often referred to as metabolic hormones because their levels influence the
body’s [Show Less]