Major Endocrine Organs

Thyroid (Gland)

What gland in the body is highly vascular, is the largest pure endocrine gland in the body, and is located anterior to the neck, on the trachea, inferior to the larynx?

follicles

The thyroid gland is composed of spherical (BLANK) that are either cuboidal or squamous epithelial cells

Follicle (Cells)

What cells in the thyroid gland produce thyroglobulin with a central cavity that stores colloid that consist of thyroglobulin molecules with attached iodine atoms?

Parafollicular (Cells)

What cells in the thyroid gland produce calcitonin?

thyroid gland

What gland is the Thyroid Hormone produced and released from?

Thyroxine (T4)

What is the term for a Thyroid Hormone that has 4 iodines attached to it?

Triiodothyronine (T3)

What is the term for a Thyroid Hormone that has 3 iodines attached to it?

Thyroid Hormone

What hormone has the following functions:

1. Calorigenic effect: increases metabolism which increases body heat production

2. Helps maintain blood pressure

3. Regulates tissue growth and development

4. Important for normal development of the skeletal and nervous systems

5. Plays a role in reproductive capabilities

TSH (thyroid stimulating hormone), thyroglobulin, iodine, Iodination, coupling, endocytosis, release

[Synthesis of the Thyroid Hormone]

1. (BLANK1) is secreted from the anterior pituitary and binds to follicle cell receptors

2. (BLANK2) is formed by ribosomes and transported via the Golgi Apparatus for storage in the lumen

3. Iodide trapping and oxidation to (BLANK3)

4. (BLANK4) (add an iodine) to create T1 and T2

5. (BLANK5) of T2 and T1 (creating T3 or T4)

6. Colloid (BLANK6) (using lysosomes)

7. Cleavage of hormones for (BLANK7)

Thyroxine-binding globulins (TBGs)

What is the term for the transport protein that T3 and T4 bind to immediately? (similar to steroid based hormones, they are lipid soluble)

T3

Which hormone (T3 or T4) binds more readily to target cell receptors and has enzymes to convert one to the other?

direct gene activation, lipid soluble

Does the Thyroid Hormone use second messenger systems or direct gene activation? Why?

T4/T3

Rising levels of what thing in the body inhibit the hypothalamic-adenohypophyseal axis?

• increased of this turns off anterior pituitary: Thyroid Releasing Hormone (TSH) and also hypothalamus: Thyrotropin-Releasing Hormone (TRH)

  However

• Certain conditions can cause the release of TRH from the hypothalamus and can override the negative feedback

Myxedema

What is the term for the homeostatic imbalance when there is a full-blown hypothyroid syndrome leading to:

• Low metabolic rate, feeling chilled, dry skin, puffy eyes, edema, lethargy, and mental sluggishness

• May be caused by lack of iodine which produces goiter

goiter

Lack of iodine in the body may result in what condition happening?

Graves’ Disease

What is the term for the homeostatic imbalance of the most common hyperthyroid condition leading to:

• Elevated metabolic rate, sweating, rapid heartbeat, nervousness, and weight loss despite adequate food intake

• Protrusion of the eyeballs

Calcitonin

What hormone functions by lowering blood calcium levels?

• Targets the skeleton and inhibits osteoclasts activity and inhibits releases Ca2⁺ from the bony matrix

• Stimulates uptake of Ca2⁺ and incorporation into bones

parafollicular cells (of the thyroid glands)

What cells (from where) is Calcitonin produced in and released from?

calcitonin

Declining blood levels of what thing inhibits parafollicular cell activity? (negative feedback)

Parathyroid Glands

What is the term for the 4-8 glands on the posterior aspect of the thyroid that are glandular cells arranged in cords containing scatter oxyphil cells and smaller chief cells?

Chief and Oxyphil (Cells)

What are the names of the 2 cells of the parathyroid glands?

Chief (Cells)

Which cells of the parathyroid glands secrete parathyroid hormone (PTH)?

Oxyphil (Cells)

Which cells of the parathyroid glands have an unclear function?

Parathyroid Hormone

What hormone functions by increasing Ca²⁺ levels by targeting the skeleton, kidneys, and intestines and is the single *most important* hormone controlling calcium balance of the blood?

Parathyroid Hormone

What hormone acts as an antagonist to Calcitonin?

Calcium (Ca²⁺)

Decreasing levels of what in the blood trigger the release of the Parathyroid Hormone?

Chief Cells (of the Parathyroid Glands)

What cells (from where) is the Parathyroid Hormone produced in and released from?

(Adrenal) Medulla and Cortex

Technically, each adrenal gland is two functioning endocrine glands called what?

Adrenal Medulla (interior region)

Which part of the Adrenal Glands are part of the sympathetic nervous system?

Adrenal Cortex (exterior region)

Which part of the Adrenal Glands are glandular tissue making up the bulk of the gland?

cholesterol

What are Corticosteroids synthesized from?

(Zona) Glomerulosa, Fasciculata, Reticularis

What are the 3 layers of the Adrenal Cortex?

Zona Glomerulosa

Which layer of the Adrenal cortex produces Mineralocorticoids?

Zona Fasciculata

Which layer of the Adrenal cortex produces Glucocorticoids?

Zona Reticularis

Which layer of the Adrenal cortex produces Gonadocorticoids?

Mineralocorticoids

Which hormone functions by regulating electrolyte concentrations (sodium and potassium) in extracellular fluids?

• Produced in and released from: Adrenal cortex, Zona Glomerulosa

Aldosterone

What hormone is responsible for maintaining Na⁺ balance by reducing excretion and enhancing absorption of Na⁺?

Sodium (Na⁺)

What ion plays a major role in water balance, blood volume, and blood pressure and also helps to regulate K⁺, H⁺, HCO3^-, and Cl^- when it is being regulated as well?

Aldosterone

The following triggers the secretion of what hormone:

• Rising blood levels of K⁺

• Low blood levels of Na⁺

• Decreasing blood volume and pressure

Humoral

Rising/Lowering Blood levels causing the release of a hormone are what type of stimuli?

• Humoral

• Neural

• Hormonal

Renin-angiotensin mechanism, Plasma concentration of Na⁺ and K⁺, ACTH, ANP

What are the 4 ways of regulating Aldosterone?

Osmolarity

What is the term for the number of solutes dissolved in a solvent?

Renin, angiotensinogen, angiotensin I, angiotensin II, aldosterone

[Renin-Angiotensin Mechanism]

Specialized kidney cells are activated when Blood Volume or Pressure and Osmolarity drops

1. Release of (BLANK1): enzyme from kidneys

2. (BLANK1) cleaves off a part of the protein (BLANK2) to form (BLANK3)

3. (BLANK3) converts to (BLANK4) by the help of angiotensin converting enzyme (ACE)

4. (BLANK4) stimulates (BLANK5) release, which increases Na⁺ reabsorption (to increase bp)

Renin

What is the term for the enzyme from the kidneys?

Stimulate, Inhibit

(Stimulate/Inhibit) Release of Aldosterone:

• Increased K⁺

• Decreased Na⁺

(Stimulate/Inhibit) Release of Aldosterone:

• Decreased K⁺

• Increased Na⁺

CRH (Corticotrophin-Releasing Hormone), ACTH (Adrenocorticotropic Hormone)

Hypothalamus/(BLANK1) » Anterior Pituitary/(BLANK12) » Adrenal Cortex/aldosterone

ANP

What hormone is secreted by the heart when BP rises and functions to inhibit the renin-angiotensin mechanism and results in decreased BP?

• Blocks renin and aldosterone secretion

• Inhibits angiotensin-induced mechanisms that enhance water and Na⁺ reabsorption

Glucocorticoids

What hormone in the body:

• Influence energy metabolism of the body’s cells and help us resist stressors

• Help the body adapt to food intake by keeping blood sugar stable and maintaining blood volume

• During stress, helps the body negotiate crisis

• Produced in and released from: Adrenal cortex, Zona Fasciculata

• Function: Trigger gluconeogenesis: creation of new glucose

Cortisol

What is the major type of glucocorticoids besides cortisone and corticosterone?

CRH (Corticotrophin-Releasing Hormone), ACTH (Adrenocorticotropic Hormone)

Hypothalamus/(BLANK1) » Anterior Pituitary Gland/(BLANK2) » Adrenal Cortex, Zona Fasciculata/Glucocorticoids

gluconeogensis

What is the term for the creation of new glucose?

cortisol

[Glucocorticoids] Negative feedback: rising levels of (BLANK) act on hypothalamus and anterior pituitary

highest, lowest

[Cortisol]

Daily cycle: (BLANK1) in the morning after we arise (BLANK2) after we fall asleep

formation, inflammation, immune system, changes

Excess of cortisol causes

• Depress cartilage and bone (BLANK1)

• Inhibit (BLANK2)

• Depress (BLANK3)

• Promote (BLANK4) in CV, neural, and GI functioning

Cushing’s Disease

What homeostatic imbalance is described:

• Cause: ACTH-releasing tumor or high doses of glucocorticoid drugs

• Symptoms: persistent hyperglycemia, loss of muscle and bone, hypertension, and edema (caused by water and Na⁺ retention)

• Treatment: removal of the cause

Addison’s Disease

What homeostatic imbalance is described:

• Cause: hyposecretion/low secretion of mineralocorticoids and glucocorticoids

• Symptoms: weight loss, low glucose and Na⁺ levels, and increased K⁺ levels; dehydration and hypotension

• Treatment: corticosteroid replacement therapy

Gonadocorticoids

What hormones are

• weak androgens that are converted to testosterone or estrogens in tissue cells

• Produced in and released from: Adrenal Cortex, Zona Reticularis

• Function: contribute to the onset of puberty

Adrenal Medulla

What is:

• Part of the autonomic nervous system

• Synthesis of catecholamines

  • Epinephrine

  • Norepinephrine

• “Fight or Flight”

Chromaffin (Cells)

What are modified ganglionic sympathetic neurons in the Adrenal Medulla to help stimulate the release of hormones (neural stimulus)?

Catecholamines

What hormone is described:

• Produced in and released from: adrenal medulla

• Function: fight or flight situations

• Brief responses

• Unequal amounts stored and released

Epinephrine

What type of catecholamine stimulates heart and metabolic activates and is 80 percent of the hormones in the adrenal medulla?

Norepinephrine

What type of catecholamine stimulates vasoconstriction of peripheral vessels changing BP and is 20 percent of the hormones in the adrenal medulla?

Pineal (Gland)

What gland is on the roof of the 3^rd ventricle in the diencephalon and releases melatonin?

Pinealocytes

What is the term of the secretory cells in the Pineal Gland?

Melatonin

What hormone functions by having peak levels at night to make us drowsy for sleep?

Pancrease

What gland is a mix of both endocrine and exocrine gland?

Acinar Cells

What produces enzymes for digestion (exocrine) in the Pancreas?

Pancreatic Islets (Islets of Langerhans)

What is the term for the tiny cell clusters that produce pancreatic hormones in the Pancrease?

Alpha (Cells)

What cells in the Pancreas produces glucagon?

Beta (Cells)

What cells in the Pancreas produce insulin?

antagonist

Glucagon and Insulin are (synergist/antagonist) to each other

Glucagon

What hormone has the following functions:

• Promote the breakdown of glycogen to glucose

• Synthesis of glucose from lactic acid and nonCHO molecules

• Release of glucose to the blood from the liver

stimulate, inhibit

[Glucagon: Humoral Stimuli]

Falling levels of glucose in the blood (stimulate/inhibit) the release of glucagon.

Rising levels of glucose in the blood (stimulate/inhibit) the release of glucagon.

Insulin

What hormone has the following functions:

• Enhances membrane transport of glucose into body cells

• Inhibits the breakdown of glycogen to glucose

• Inhibits the conversion of amino acids or fats to glucose

inhibit, stimulate

[Insulin: Humoral Stimuli]

Falling levels of glucose in the blood (stimulate/inhibit) the release of insulin.

Rising levels of glucose in the blood (stimulate/inhibit) the release of insulin.

Diabetes Mellitus

What homeostatic imbalance is described:

• Caused by hyposecretion or hypoactivity of insulin

• Results in increased blood glucose levels (insulin can’t get blood sugar into cells)

• Symptoms: polyuria, polydipsia, polyphagia

Type 1

What type of diabetes mellitus has a lack of insulin production?

Type 2

What type of diabetes mellitus has target cells insensitive to insulin?

Estrogens and Progesterone

What hormones is produced in the ovaries and has the following functions:

• Maturation of reproductive organs and appearance of secondary sex characteristics (e——— only)

• Promote breast development and control menstrual cycle (e—— and p———)

Testosterone

What hormone is produced in the testes along with sperm and has the following functions:

• Maturation of reproductive organs and appearance of secondary sex characteristics

• Sperm production

Heart, Kidneys

[Other Organs that are not endocrine that Secrete Hormones]

1. (BLANK1) - Atrial natriuretic peptide (ANP)***

2. Gastrointestinal tract - Peptide hormones

3. (BLANK2) - Erythropoietin (EPO) and Renin***

4. Skin - Cholecalciferol

5. Adipose (fat) tissue - Leptin, resistin, and adiponectin

6. Skeleton - Osteocalcin

7. Thymus - Thymulin, thymopoietins, thymosins