Endocrine System Case Study
The Endocrine System
Vincent Schwartz
Laszlo Vass, Ed.D. Version 42-0023-01-01
Purpose
What is the purpose of this exercise? Are there any safety concerns associated with this exercise? If so, list what they are and what precautions should be taken.
Students will identify the major endocrine glands and tissues of the body. Students will relate each endocrine gland to the appropriate hormone. Students will explain how each hormone helps the body maintain homeostasis. Students will identify the histology of the major endocrine glands and relate it to their structure and function.
Exercise 1: The Pituitary Gland …show more content…
Observations
Please describe in detail the structures and features you observed on the pituitary gland slide.
Visible are the pars distalis (A), Pars intermedia (B) and the pars nervosa (C).
Data Table 1: Do some research and fill in the data table below. | Hormone | Functions | Adrenocorticotropic hormone (ACTH) | stimulates secretion of glucocorticoid steroid hormones from adrenal cortex cells | Antidiuretic hormone (ADH) | stimulates water reabsorption | Follicle stimulating hormone (FSH) | regulates the development, growth, pubertal maturation, and reproductive processes | Growth hormone (GH) | stimulates growth/ cell reproduction and regeneration | Luteinizing hormone (LH) | In females triggers ovulation[3] and development of the corpus luteum. In males it stimulates Leydig cell production of testosterone. | Melanocyte stimulating hormone (MSH) | stimulates the production and release of melanin in the skin and hair | Oxytocin | Stimulates uterine contraction during childbirth, encourages mother-child bonding immediately after birth, and aids in the production and ejection of milk during breastfeeding. | Prolactin (PRL) | Stimulates the production of breast milk and breast enlargement to prepare for production of milk, sexual gratification. | Thyroid stimulating hormone (TSH) | stimulates the thyroid gland to produce thyroxine and then triiodothyronine, which stimulates the metabolism of nearly every tissue in the body. |
Questions
A. Describe the function of the endocrine system.
The endocrine system secretes hormones into the bloodstream to maintain homeostasis within the body. The endocrine system is responsible for stimulating growth, sexual development, water reabsorption, uterine contraction during childbirth, maintaining electrolyte balance, and other major functions that keep the body’s balance on par.
B. What is a gland?
A gland is an organ within the body that synthesizes a substance, such as hormones, for release into the bloodstream (Endocrine) or to the body’s surface (Exocrine).
C. Describe how negative feedback regulates the secretion of most hormones.
The negative feedback system regulates hormones by monitoring the level within the bloodstream. For example, if the Thyroid Hormone (TH) is high then Thyroid Stimulating Hormone (TSH) will remain moderate. However, if the levels of TH drop within the bloodstream, the level of TSH will rise to stimulate the thyroid to release more TH. This allows the body to keep the hormones near the set point necessary to maintain homeostasis.
D. Why is the pituitary gland called the “master endocrine gland”?
The pituitary gland, which is controlled in large part by the hypothalamus of the brain, is responsible for secreting hormones that control or regulate the majority of the other endocrine glands within the body. For this reason, the pituitary gland is often known as the “Master” endocrine gland.
Exercise 2: The Thyroid Gland Observations
Please describe in detail the structures and features you observed on the thyroid gland slide.
Visible are the thyroid follicles (A), Colloid (B), and parafollicular cells (C).
Questions
A. What is the overall function of the thyroid gland?
The thyroid gland is responsible for regulating the use of energy, protein synthesis, and the sensitivity of the body to other hormones. Ultimately, the thyroid regulates our metabolism.
B. What is the function of thyroxin?
The Function of thyroxin, also known as T4, Is to regulate the body’s metabolism, rate of oxygen consumption, and the rate at which the body generates heat.
B. What is the function of triiodothyronine?
Trioodothyronine, T3, is the most powerful hormone secreted by the thyroid gland. It serves to regulate growth and development, heart rate, metabolism, and the generation of body heat.
C. What is the function of calcitonin?
Calcitonin serves to reduce the levels of calcium within the bloodstream. It promotes the renal excretion of calcium when serum calcium levels are too high.
D. What is hyperthyroidism? What are its effects on the body?
Hyperthyroidism occurs when the thyroid produces too much thyroid hormone. Also known as “Overactive” thyroid. The excess production of thyroid hormone may result in rapid weight loss, tachycardia, excessive sweat production, or mood changes.
Exercise 3: The Parathyroid Glands Observations
Please describe in detail the structures and features you observed on the parathyroid gland slide.
Visible is the parathyroid tissue (A), which is embedded in thyroid tissue (B).
Questions
A. What does parathyroid hormone (PTH) do?
Parathyroid hormone serves to increase calcium levels in the bloodstream. It has an opposite action to calcitonin.
B. Based on your answer to Question A, can you live without your parathyroid glands? Why or why not?
Yes, it is possible to live without parathyroid glands. Due to feedback looks involved in hormone secretion if a person does not have a parathyroid gland to secrete PTH, the thyroid should sense the lack of PTH and subsequently secrete less calcitonin to reduce the serum calcium. Since the body wants to maintain homeostasis, if it is unable to arbitrarily increase calcium levels it will not continue to release a calcium reducing hormone.
Exercise 4: The Thymus Gland
Observations
Please describe in detail the structures and features you observed on the thymus gland slide.
Visible is the dark staining of the cortex (A) and the lighter staining of the medulla (B).
Questions
A. What does the hormone thymosin do?
Thymosin is secreted by the thymus gland and stimulates the development of T lymphocytes. T lymphocytes function within the immune system to recognize and destroy foreign antigens.
B. Based on your answer to Question A, explain why the thymus gland shrinks as we reach adulthood.
The thymus gland is responsible for the development and instruction of t lymphocytes, which serve to identify and destroy foreign antigens. As we mature and our immune system develops there is less and less need for the development of t lymphocytes stimulated by the thymus gland. Due to this the thymus gland slowly atrophies as we age, eventually turning into a clump of fatty tissue.
Exercise 5: The Adrenal Gland
Observations
Please describe in detail the structures and features you observed on the adrenal gland slide
Visible is the capsule (A), cortex (B), and medulla (C). Within these layers are the Zona glomerulosa, zona fasciculata, and zona reticularis.
Questions
A. The adrenal glands are in part controlled by the sympathetic and parasympathetic branches of the autonomic nervous system. Name the hormones involved in this regulation and the functions of each.
The adrenal medulla releases three hormones in response to fear, pain, or stress: Epinephrine, norepinephrine, and trace amounts of dopamine. These hormones raise alertness, increase heart rate, increase pulmonary airflow, stimulate circulation to the muscles, gluconeogenesis, and inhibit temporarily unnecessary functions such as digestion and urine production.
The adrenal cortex also secretes corticosteroids which have three main functions. Mineralcorticoids regulate electrolyte balance, glucocorticoids regulate metabolism of glucose, and other organic fuels, and sex steroids such as androgens, which stimulate the growth of pubic hair, and stimulate libido.
B. Where in the adrenal gland are mineralocorticoids made?
Mineralcorticoids are made in the adrenal cortex, specifically in the thin layer known as the zona glomerulosa.
C. What are the functions of mineralocorticoids? Give an example of a mineralocorticoid hormone.
Aldosterone is the most significant mineralcorticoid. Aldosterone stimulates the kidneys to retain sodium in body fluids and excrete potassium in urine. Ultimately, aldosterone aids in maintaining blood volume and pressure.
D. Where in the adrenal glands are glucocorticoids made?
Glucocorticoids are made in the zona fasciculate, the thick middle layer of the cortex.
E. What are the functions of glucocorticoids? Give an example of a glucocorticoid.
Glucocorticoids serve to regulate the metabolism of glucose, and other organic fuels within the body. The most potent glucocorticoid is cortisol.
Exercise 6: The Pancreas Observations
Please describe in detail the structures and features you observed on the pancreas slide
Visible are the islets of Langerhans (A).
Questions
A. Explain the difference between an exocrine gland and an endocrine gland.
Exocrine glands secrete their hormones through ducts to the surface of organs such as the skin or the digestive tract. Endocrine glands are ductless. Endocrine glands secrete hormones directly into the bloodstream. Endocrine glands have intracellular functions while exocrine glands have extracellular functions.
B. What is the exocrine function of the pancreas?
The pancreas is primarily an exocrine digestive gland. The pancreas produces amylase which aids in digestion of starch.
C. What endocrine hormones does the pancreas produce? What is the function of each?
Glucagon- stimulates gluconeogenesis, glycogenolysis, and the release of glucose into circulation.
Insulin- stimulates cells to absorb glucose, fatty acids, and amino acids or metabolizes them.
Somatostatin- Inhibits some digestive enzyme secretion and nutrient absorption.
Pancreatic polypeptide- Inhibits gallbladder and intestinal contractions and the secretion of stomac acid.
Gastrin- Stimulates secretion of stomach acids, motility and emptying of the stomach.
D. Diabetes is a serious health problem in the United States. Explain what diabetes is and the differences between the Type 1 and Type 2 forms of the disease.
Diabetes is a disease where the body cannot process glucose or use glucose appropriately due to a lack of insulin production or inability to properly use insulin. This results in hyperglycemia, which may lead to several other medical conditions. Type 1 diabetes, formerly known as insulin dependent diabetes or juvenile diabetes is usually result of inadequate insulin production and is treated by taking insulin. Type 2 diabetes, non-insulin dependent diabetes, or adult onset diabetes results from the body’s inability to effectively use insulin. Type 2 diabetes is often treated with diet control, daily medication, and exercise.
Exercise 7: The Gonads Observations
Please describe in detail the structures and features you observed on the testes and ovary slides
Ovary- Visible are the primary follicle (A), and the Graafian follicle with oocyte (B).
Testis- Visible are the Seminiferous tubules (A) and the interstitial cells (B).
Questions
A. What are the endocrine functions of the testes?
The endocrine functions of the testes include the secretion of testosterone and small amounts of other androgens, estrogens, and inhibin.
B.
What does testosterone do?
Testosterone stimulates the development of the male reproductive system in the fetus and adolescent. It also stimulates the development of masculine physique and sex drive in adolescence. Testosterone is also responsible for sustaining sperm production and sexual instinct throughout adult life.
C. What are the endocrine functions of the ovaries?
The ovaries secrete estradiol, progesterone, and inhibin. D. What do estrogen and progesterone do?
Estrogen and progesterone are responsible for development of the female physique, female reproductive system, regulation of the menstrual cycle, sustaining pregnancy, and preparation of the mammary glands for lactation.
E. How do birth control pills work in terms of endocrine function?
Birth control pills attempt to deceive the body into thinking it is already pregnant. It does this my increasing either estrogen or progesterone levels to mimic that of a pregnant female. Since the body does not release additional eggs if the female is already pregnant, the likelihood of conception is minimalized by the use of birth control.
Exercise 8: Cat Dissection: Endocrine …show more content…
System Matching
Match each structure in the left column with its correct description from the right column.
C | 1. Pancreas | A. divided into two lobes called lateral lobes | D | 2. Adrenal medulla | B. secretes hormone that raises the number of calcium ions in the blood | A | 3. Thyroid gland | C. has both exocrine and endocrine functions | B | 4. Parathyroid gland | D. activated when body is under emotional stress | F | 5. Ovary | E. general term for sex organs | E | 6.
Gonads | F. source of both estrogen and progesterone |
Exercise 9: Endocrine System Roundup Questions
A. Describe the effects that a malfunctioning pituitary gland would have on an individual?
A malfunctioning pituitary gland may lead to disorders of other glands or systemic diseases. Some symptoms may include infertility, diabetes insipidus, and inability to regulate other important endocrine hormones.
B. Which endocrine glands would be most affected by prolonged mental stress on the body? (i.e work, lack of time, worrying etc.) Explain your reasoning.
The glands that would be most affected my prolonged mental stress are the adrenal glands. The adrenal glands secrete hormones in response to fear, pain, or stress. Prolonged stress may result in electrolyte imbalance, increased metabolism, and altered sex drive. Prolonged periods of stress may lead to exhaustion of body resources.
C. Explain, in general, how a hormone works.
Hormones are secreted into the bloodstream by endocrine glands. The hormones act upon receptor sites called “target cells”. Hormones will only act upon these specific receptors. Once the hormone reaches the target cell a series of chemical and physiological changes occur, which produce the desired outcome necessary to maintain
homeostasis.
Vincent Schwartz
Laszlo Vass, Ed.D. Version 42-0023-01-01
Purpose
What is the purpose of this exercise? Are there any safety concerns associated with this exercise? If so, list what they are and what precautions should be taken.
Students will identify the major endocrine glands and tissues of the body. Students will relate each endocrine gland to the appropriate hormone. Students will explain how each hormone helps the body maintain homeostasis. Students will identify the histology of the major endocrine glands and relate it to their structure and function.
Exercise 1: The Pituitary Gland …show more content…
Observations
Please describe in detail the structures and features you observed on the pituitary gland slide.
Visible are the pars distalis (A), Pars intermedia (B) and the pars nervosa (C).
Data Table 1: Do some research and fill in the data table below. | Hormone | Functions | Adrenocorticotropic hormone (ACTH) | stimulates secretion of glucocorticoid steroid hormones from adrenal cortex cells | Antidiuretic hormone (ADH) | stimulates water reabsorption | Follicle stimulating hormone (FSH) | regulates the development, growth, pubertal maturation, and reproductive processes | Growth hormone (GH) | stimulates growth/ cell reproduction and regeneration | Luteinizing hormone (LH) | In females triggers ovulation[3] and development of the corpus luteum. In males it stimulates Leydig cell production of testosterone. | Melanocyte stimulating hormone (MSH) | stimulates the production and release of melanin in the skin and hair | Oxytocin | Stimulates uterine contraction during childbirth, encourages mother-child bonding immediately after birth, and aids in the production and ejection of milk during breastfeeding. | Prolactin (PRL) | Stimulates the production of breast milk and breast enlargement to prepare for production of milk, sexual gratification. | Thyroid stimulating hormone (TSH) | stimulates the thyroid gland to produce thyroxine and then triiodothyronine, which stimulates the metabolism of nearly every tissue in the body. |
Questions
A. Describe the function of the endocrine system.
The endocrine system secretes hormones into the bloodstream to maintain homeostasis within the body. The endocrine system is responsible for stimulating growth, sexual development, water reabsorption, uterine contraction during childbirth, maintaining electrolyte balance, and other major functions that keep the body’s balance on par.
B. What is a gland?
A gland is an organ within the body that synthesizes a substance, such as hormones, for release into the bloodstream (Endocrine) or to the body’s surface (Exocrine).
C. Describe how negative feedback regulates the secretion of most hormones.
The negative feedback system regulates hormones by monitoring the level within the bloodstream. For example, if the Thyroid Hormone (TH) is high then Thyroid Stimulating Hormone (TSH) will remain moderate. However, if the levels of TH drop within the bloodstream, the level of TSH will rise to stimulate the thyroid to release more TH. This allows the body to keep the hormones near the set point necessary to maintain homeostasis.
D. Why is the pituitary gland called the “master endocrine gland”?
The pituitary gland, which is controlled in large part by the hypothalamus of the brain, is responsible for secreting hormones that control or regulate the majority of the other endocrine glands within the body. For this reason, the pituitary gland is often known as the “Master” endocrine gland.
Exercise 2: The Thyroid Gland Observations
Please describe in detail the structures and features you observed on the thyroid gland slide.
Visible are the thyroid follicles (A), Colloid (B), and parafollicular cells (C).
Questions
A. What is the overall function of the thyroid gland?
The thyroid gland is responsible for regulating the use of energy, protein synthesis, and the sensitivity of the body to other hormones. Ultimately, the thyroid regulates our metabolism.
B. What is the function of thyroxin?
The Function of thyroxin, also known as T4, Is to regulate the body’s metabolism, rate of oxygen consumption, and the rate at which the body generates heat.
B. What is the function of triiodothyronine?
Trioodothyronine, T3, is the most powerful hormone secreted by the thyroid gland. It serves to regulate growth and development, heart rate, metabolism, and the generation of body heat.
C. What is the function of calcitonin?
Calcitonin serves to reduce the levels of calcium within the bloodstream. It promotes the renal excretion of calcium when serum calcium levels are too high.
D. What is hyperthyroidism? What are its effects on the body?
Hyperthyroidism occurs when the thyroid produces too much thyroid hormone. Also known as “Overactive” thyroid. The excess production of thyroid hormone may result in rapid weight loss, tachycardia, excessive sweat production, or mood changes.
Exercise 3: The Parathyroid Glands Observations
Please describe in detail the structures and features you observed on the parathyroid gland slide.
Visible is the parathyroid tissue (A), which is embedded in thyroid tissue (B).
Questions
A. What does parathyroid hormone (PTH) do?
Parathyroid hormone serves to increase calcium levels in the bloodstream. It has an opposite action to calcitonin.
B. Based on your answer to Question A, can you live without your parathyroid glands? Why or why not?
Yes, it is possible to live without parathyroid glands. Due to feedback looks involved in hormone secretion if a person does not have a parathyroid gland to secrete PTH, the thyroid should sense the lack of PTH and subsequently secrete less calcitonin to reduce the serum calcium. Since the body wants to maintain homeostasis, if it is unable to arbitrarily increase calcium levels it will not continue to release a calcium reducing hormone.
Exercise 4: The Thymus Gland
Observations
Please describe in detail the structures and features you observed on the thymus gland slide.
Visible is the dark staining of the cortex (A) and the lighter staining of the medulla (B).
Questions
A. What does the hormone thymosin do?
Thymosin is secreted by the thymus gland and stimulates the development of T lymphocytes. T lymphocytes function within the immune system to recognize and destroy foreign antigens.
B. Based on your answer to Question A, explain why the thymus gland shrinks as we reach adulthood.
The thymus gland is responsible for the development and instruction of t lymphocytes, which serve to identify and destroy foreign antigens. As we mature and our immune system develops there is less and less need for the development of t lymphocytes stimulated by the thymus gland. Due to this the thymus gland slowly atrophies as we age, eventually turning into a clump of fatty tissue.
Exercise 5: The Adrenal Gland
Observations
Please describe in detail the structures and features you observed on the adrenal gland slide
Visible is the capsule (A), cortex (B), and medulla (C). Within these layers are the Zona glomerulosa, zona fasciculata, and zona reticularis.
Questions
A. The adrenal glands are in part controlled by the sympathetic and parasympathetic branches of the autonomic nervous system. Name the hormones involved in this regulation and the functions of each.
The adrenal medulla releases three hormones in response to fear, pain, or stress: Epinephrine, norepinephrine, and trace amounts of dopamine. These hormones raise alertness, increase heart rate, increase pulmonary airflow, stimulate circulation to the muscles, gluconeogenesis, and inhibit temporarily unnecessary functions such as digestion and urine production.
The adrenal cortex also secretes corticosteroids which have three main functions. Mineralcorticoids regulate electrolyte balance, glucocorticoids regulate metabolism of glucose, and other organic fuels, and sex steroids such as androgens, which stimulate the growth of pubic hair, and stimulate libido.
B. Where in the adrenal gland are mineralocorticoids made?
Mineralcorticoids are made in the adrenal cortex, specifically in the thin layer known as the zona glomerulosa.
C. What are the functions of mineralocorticoids? Give an example of a mineralocorticoid hormone.
Aldosterone is the most significant mineralcorticoid. Aldosterone stimulates the kidneys to retain sodium in body fluids and excrete potassium in urine. Ultimately, aldosterone aids in maintaining blood volume and pressure.
D. Where in the adrenal glands are glucocorticoids made?
Glucocorticoids are made in the zona fasciculate, the thick middle layer of the cortex.
E. What are the functions of glucocorticoids? Give an example of a glucocorticoid.
Glucocorticoids serve to regulate the metabolism of glucose, and other organic fuels within the body. The most potent glucocorticoid is cortisol.
Exercise 6: The Pancreas Observations
Please describe in detail the structures and features you observed on the pancreas slide
Visible are the islets of Langerhans (A).
Questions
A. Explain the difference between an exocrine gland and an endocrine gland.
Exocrine glands secrete their hormones through ducts to the surface of organs such as the skin or the digestive tract. Endocrine glands are ductless. Endocrine glands secrete hormones directly into the bloodstream. Endocrine glands have intracellular functions while exocrine glands have extracellular functions.
B. What is the exocrine function of the pancreas?
The pancreas is primarily an exocrine digestive gland. The pancreas produces amylase which aids in digestion of starch.
C. What endocrine hormones does the pancreas produce? What is the function of each?
Glucagon- stimulates gluconeogenesis, glycogenolysis, and the release of glucose into circulation.
Insulin- stimulates cells to absorb glucose, fatty acids, and amino acids or metabolizes them.
Somatostatin- Inhibits some digestive enzyme secretion and nutrient absorption.
Pancreatic polypeptide- Inhibits gallbladder and intestinal contractions and the secretion of stomac acid.
Gastrin- Stimulates secretion of stomach acids, motility and emptying of the stomach.
D. Diabetes is a serious health problem in the United States. Explain what diabetes is and the differences between the Type 1 and Type 2 forms of the disease.
Diabetes is a disease where the body cannot process glucose or use glucose appropriately due to a lack of insulin production or inability to properly use insulin. This results in hyperglycemia, which may lead to several other medical conditions. Type 1 diabetes, formerly known as insulin dependent diabetes or juvenile diabetes is usually result of inadequate insulin production and is treated by taking insulin. Type 2 diabetes, non-insulin dependent diabetes, or adult onset diabetes results from the body’s inability to effectively use insulin. Type 2 diabetes is often treated with diet control, daily medication, and exercise.
Exercise 7: The Gonads Observations
Please describe in detail the structures and features you observed on the testes and ovary slides
Ovary- Visible are the primary follicle (A), and the Graafian follicle with oocyte (B).
Testis- Visible are the Seminiferous tubules (A) and the interstitial cells (B).
Questions
A. What are the endocrine functions of the testes?
The endocrine functions of the testes include the secretion of testosterone and small amounts of other androgens, estrogens, and inhibin.
B.
What does testosterone do?
Testosterone stimulates the development of the male reproductive system in the fetus and adolescent. It also stimulates the development of masculine physique and sex drive in adolescence. Testosterone is also responsible for sustaining sperm production and sexual instinct throughout adult life.
C. What are the endocrine functions of the ovaries?
The ovaries secrete estradiol, progesterone, and inhibin. D. What do estrogen and progesterone do?
Estrogen and progesterone are responsible for development of the female physique, female reproductive system, regulation of the menstrual cycle, sustaining pregnancy, and preparation of the mammary glands for lactation.
E. How do birth control pills work in terms of endocrine function?
Birth control pills attempt to deceive the body into thinking it is already pregnant. It does this my increasing either estrogen or progesterone levels to mimic that of a pregnant female. Since the body does not release additional eggs if the female is already pregnant, the likelihood of conception is minimalized by the use of birth control.
Exercise 8: Cat Dissection: Endocrine …show more content…
System Matching
Match each structure in the left column with its correct description from the right column.
C | 1. Pancreas | A. divided into two lobes called lateral lobes | D | 2. Adrenal medulla | B. secretes hormone that raises the number of calcium ions in the blood | A | 3. Thyroid gland | C. has both exocrine and endocrine functions | B | 4. Parathyroid gland | D. activated when body is under emotional stress | F | 5. Ovary | E. general term for sex organs | E | 6.
Gonads | F. source of both estrogen and progesterone |
Exercise 9: Endocrine System Roundup Questions
A. Describe the effects that a malfunctioning pituitary gland would have on an individual?
A malfunctioning pituitary gland may lead to disorders of other glands or systemic diseases. Some symptoms may include infertility, diabetes insipidus, and inability to regulate other important endocrine hormones.
B. Which endocrine glands would be most affected by prolonged mental stress on the body? (i.e work, lack of time, worrying etc.) Explain your reasoning.
The glands that would be most affected my prolonged mental stress are the adrenal glands. The adrenal glands secrete hormones in response to fear, pain, or stress. Prolonged stress may result in electrolyte imbalance, increased metabolism, and altered sex drive. Prolonged periods of stress may lead to exhaustion of body resources.
C. Explain, in general, how a hormone works.
Hormones are secreted into the bloodstream by endocrine glands. The hormones act upon receptor sites called “target cells”. Hormones will only act upon these specific receptors. Once the hormone reaches the target cell a series of chemical and physiological changes occur, which produce the desired outcome necessary to maintain
homeostasis.