Chapter 18 Endocrine System Study Prompts

Can you define "endocrine system"?

Cells, tissues, glands and organs that make and secrete a product called a hormone into the blood to control the activity of body cells.

Which other system of the body does the endocrine system interact with?

Nervous

Is the action of the endocrine system slower or faster compared to the nervous system? How about the effect?

slower, but the effects are long-lasting

Can you compare and contrast endocrine glands and exocrine glands?

• exocrine glands have a true duct and release their products onto a body cavity.

• Endocrine glands are ductless and release their product into the blood.

Can you describe the characteristics of endocrine glands?

Ductless glands that secrete a product called a hormone

Do you know which endocrine gland can also be classified as a neuroendocrine gland?

hypothalamus

Can you list the various endocrine glands, organs, tissues and cells? Which of them are purely endocrine and which also have other functions?

List:

1. Adipose- other

2. Cardiac/heart- other

3. Kidneys- other

4. Pineal- pure

5. Hypothalamus- pure; also called a neuroendocrine gland

6. Thyroid- pure

7. Thymus-pure

8. Adrenal- pure

9. Pancreas- endocrine and exocrine

10. Gonads- endocrine and other

11. Parathyroid- pure

12. Pituitary- pure

Can you define a "hormone"? What are their functions and characteristics?

a chemical that is secreted into the blood to control body cells' functions

Do you know the two main types (classifications) of hormones?

amino acid based (an amino acid or protein) and steroid (synthesized from cholesterol)

Can you list the ways that a hormone can produce cellular changes in a cell?

induce secretory activity, alter plasma membrane permeability, stimulate mitosis, lead to the synthesis of proteins and activate or deactivate enzymes.

Do you know what "target specificity" means?

• only cells that have a receptor for the hormone can be altered by the hormone.

• Any cell with a receptor for the hormone is the hormone's target.

Do you know what kind of feedback system controls hormone levels in the blood?

Negative (the resultant product reaches the original secreting gland and "turns it off")

Can you describe the characteristics, size, shape and location of the pituitary gland?

• Pituitary is inferior to the hypothalamus (and connected to it by the infundibulum) and sits in the hypophyseal fossa of the sella turcica.

• It is the size and shape of a garden pea and has two lobes.

1. Do you know the names of the two lobes of the pituitary gland?

   1. Can you describe their relationship with the hypothalamus?

   2. Do you know which hormones are made by which lobe?

      1. Do you know which nuclei make which hormones?

Lobe:

1. Adenohypophysis: anterior lobe and is composed of glandular tissue (from the oral mucosa). Hormones from the ventral hypothalamic nuclei of the hypothalamus reach the adenohypophysis by the hypothalic-hypophyseal portal system. These hormones cause the anterior pituitary to secrete its hormones. See the diagram from the lecture, or from the notetaker for a list of the hormones from the hypothalamus and which hormones they cause to be released from the pituitary.

2. The neurohypophysis: posterior lobe and is the ends of the axons coming from two nuclei in the hypothalamus. The paraventricular nuclei releases oxytocin and the supraoptic nuclei releases antidiuretic hormone.

What is the tissue classification of each lobe of the pituitary gland?

anterior is epithelia and posterior is nervous

Can you describe the organization of the hypophyseal portal system?

it is a vascular pathway with two capillary beds: one for the hypothalamic hormones to enter the blood and one for the hormones to exit the blood to stimulate the pituitary.

Do you know what controls the release of the hormones from the anterior pituitary gland?

the hormones from the hypothalamus

Do you know which is the largest pure-secreting endoerine gland?

thyroid

Can you describe the shape, location and function of the thyroid gland?

• butterfly-shaped on the anterior portion of the trachea in the anterior neck.

• Secretes hormones to control calcium levels in the blood and basal metabolic rate.

Do you know the name of the structure that connects the two lobes of the thyroid gland?

isthmus

Can you describe the structure of a thyroid follicle?

• a cube or circular shaped structure with borders of simple cuboidal cells called follicle cells.

• The inside of the follicle is a substance called colloid

1. Do you know the two types of cells found in the thyroid gland?

   1. Do you know what is produced by each?

Types:

1. Follicle cells- thyroid hormone

2. Parafollicular cells- calcitonin

Do you know the functions of thyroid hormone? Do you know the two forms of thyroid hormone?

• controls basal metabolic rate (how fast your cells do cellular respiration) and controls calcium levels in the blood.

• The two forms are T3 (triiodothyronine) and T4 (thyroxine).

Can you describe the function of calcitonin?

• it is released if blood calcium levels are high and causes the bone tissue to take up calcium out of the blood, thus lowering blood calcium levels to homeostatic value.

Can you describe the shape, location and function of the parathyroid glands?

• usually four small, roundish glands on the posterior aspect of the thyroid.

• They secrete parathyroid hormone to control blood calcium levels.

What are the main types of cells in the parathyroid glands called?

chief cells

Do you know the name of the hormone made by the parathyroid glands? Do you know the function of that hormone?

• parathyroid hormone.

• Is released when blood calcium levels are low and causes the bone tissue to resorb (break down and release) calcium into the blood, therefore raises blood calcium levels to homeostatic value

Do you know the relationship between calcitonin and parathyroid hormone?

they are antagonists

Do you know the other name for adrenal glands?

suprarenal glands

Can you describe the shape, location and function of the adrenal glands?

• they are triangular (pyramid-shaped) glands that sit superior to the kidneys.

• They release various types of hormones.

Do you know the name of the two layers of tissue in the adrenal gland? What is the main difference between these two layers?

• they are triangular (pyramid-shaped) glands that sit superior to the kidneys.

• They release various types of hormones.

Do you know the classification name for hormones made in the cortex of the adrenal gland?

corticosteroids

Can you list and describe the hormones that are produced in adrenal cortex? Do you know the classification of these hormones?

Hormones:

1. mineralcorticoid called aldosterone, which controls water and salt balance at the kidney, and thus controls blood pressure.

2. cortisol, which mobilizes sugars, suppresses the immune system, is catabolic...). It is a glucocorticoid.

3. gonadocorticoids (estrogens and testosterone), which act on the gonads.

1. Do you know the name of the cells in the adrenal medulla?

   1. What hormones do these cells produce? Do you know their function?

   2. In what part of the nervous system do these hormones play a role?

• chromaffin cells.

• Epinephrine (EPI) and norepinephrine (NE).

• both play a role in the sympathetic response.

Can you describe the shape, location and function of the pancreas?

• "triangular" and posterior/inferior to the stomach.

• Serves as an exocrine and endocrine gland in the body.

Do you know the name of the cells in the pancreas that have exocrine function?

acinar cells (release digestive enzymes in a solution called pancreatic juice)

1. Do you know the name of the hormone-secreting structures in the pancreas?

   1. What are the two cell types in this structure?

   2. What hormones are produced by these cells?

      1. What is the function of these hormones?

      2. What is the relationship of these hormones?

   3. Can you describe diabetes mellitus?

   4. Do you know the isgns of this disordeR?

1. Pancreatic islets (islets of Langerhans)

   1. Alpha cells and Beta cells

   2. Hormones produced:

      1. Alpha cells- release glucagon when blood sugar levels are low. Causes cells in the liver to release glucose into the blood, thus raising blood sugar levels. Beta cells- release insulin when blood sugar levels are high. Causes body cells to uptake sugar, thus decreasing blood sugar levels.

      2. They are antagonists.

   3. A hyposecretion or hypoactivity of insulin.

   4. Polyuria (excess urination), polyphagia (excess eating/hunger), polydipsea (excess water intake/thirst), ketoacidosis (acidic condition of the blood due to ketoacids) and glycosuria (sugar in urine)

Do you know the names of the male and female gonads? What hormones are made in them?

• What functions of the body are these hormones responsible for?

• Ovary (female) and testis (male).

• Ovaries produce estrogen and progesterone.

• Testis make androgens, the most abundant being testosterone.

• They are responsible for gamete production, maturation and maintenance of sex organs and secondary sexual characteristics.

Can you describe the shape, location and function of the pineal gland?

• Do you know what hormone is produced by this gland? Do you know its function?

1. small, bean shaped organ of the epithalamus.

   1. Melatonin. Controls sleep-wake cycles by influencing the hypothalamus to make us feel tired or awake. Melatonin release peaks at night.

Can you describe the shape, location and function of the thymus?

• Do you know what hormone is produced by this gland? Do you know its function?

• bi-lobed gland found deep to the sternum and superior to the heart.

• It makes hormones that control the immunocompentancy (maturation) of T lymphocytes, which are immune cells.

• This gland tests the T cells to see if they recognize "self" antigen.

Can you list the hormones that are produced by the following?

1. Heart

2. Adipose tissue

3. Kidney

Structure:

1. Heart- atrial natriuretic hormone. Lowers blood pressure

2. Adipose- leptin- satiety (feeling full)

3. Kidney- two hormones: rennin, which raises blood pressure, and erythropoietin, which increases red blood cell production in the bone marrow.