Endocrine System Flashcards

Hormone Function

• Glands are specialized organs that secrete products.

• Endocrine glands secrete hormones globally.

• The endocrine system doesn’t include exocrine glands that secrete products locally. Exocrine glands secrete products into ducts and have local functions. Exocrine glands include oil glands, sweat glands, tear glands, salivary glands, milk glands, etc. Oil glands secrete oil into ducts that travels to surface of skin/hair for lubrication

• Hormones are chemicals that cause a bodily response.

• Hormones produced by glands are secreted into the bloodstream.

• This leads to wide distribution of hormones

• Hormones that make their way into the bloodstream can also remain active for a while

• Hormone functions include regulating growth, metabolism, and sexual development

• Hormone types include lipid-derived, amino acid-derived, and peptide hormones

• Each hormone has a specific signaling job

• Not every cell will respond to every hormone

• Hormones interact with cells through specialized receptors that match up with that particular hormone

• Increasing the number of receptors at the receiving cell can increase hormone sensitivity. Lesson 39.1 Figure 8

• Summary:

  • The endocrine system is a hormone signaling system

  • Hormones contribute to development and homeostasis

  • Hormones cause cellular changes by binding to receptors at target cells

  • Hormone types include lipid-derived, amino acid- derived, and peptide hormones

Pituitary Gland

• The pituitary gland is a small gland at the base of the brain in close association with the hypothalamus

• The pituitary gland can be divided into posterior/anterior regions each with their own hormones

Posterior Pituitary

• The posterior pituitary secretes ADH

  • Antidiuretic hormone (ADH) is produced in the hypothalamus and stored for release in the posterior pituitary

  • ADH causes water reabsorption in the kidney

  • Water moves from kidney filtrate back to blood when blood water concentration is low

• The posterior pituitary secretes Oxytocin

  • Oxytocin is produced in the hypothalamus and stored for release in the posterior pituitary

  • Oxytocin is released during breastfeeding, labor, and sexual activity

  • Receptors in a mother’s nipple are stimulated by a suckling infant and cause oxytocin release which stimulates milk ejection

  • Oxytocin is also involved in the positive feedback of contractions during childbirth

Anterior Pituitary

• The anterior pituitary secretes six hormones

  • growth hormone

  • prolactin

  • thyroid stimulating hormone

  • follicle-stimulating hormone

  • luteinizing hormone

  • adrenocorticotropic hormone

• Growth hormone promotes cell growth

  • Growth hormone promotes cell growth and division in bone, muscle, and cartilage

  • Insufficient growth hormone during development causes pituitary dwarfism

  • Excess growth hormone during development can cause gigantism

  • Excess growth hormone in adulthood causes acromegaly-thickening of bones

• Prolactin stimulates milk production

  • Pregnancy and nipple stimulation (suckling) increase prolactin levels

  • Prolactin stimulates milk production, but oxytocin triggers milk ejection from mammary tissue

• Thyroid stimulating hormone stimulates synthesis of thyroid hormone

  • The thyroid is a gland in the front of the neck

  • It produces thyroid hormone when stimulated by thyroid stimulating hormone

  • Thyroid hormone has broad effects and helps regulate metabolism and blood pressure

• Iodine is required for thyroid hormone synthesis

  • Thyroid stimulating hormone (TSH) stimulates production of thyroid hormones T3 and T4

  • If iodine levels are low, thyroid hormone cannot be produced

  • more TSH is released because thyroid hormone is still lacking

  • The thyroid becomes enlarged (goiters)

• Follicle-stimulating hormone (FSH), Luteinizing hormone (LH), Adrenocorticotropic hormone (ACTH)

  • FSH promotes development of egg cells and estrogen secretion in females/maturation of sperm in males

  • LH causes ovulation in females/testosterone production in males

  • ACTH contributes to secretion of glucocorticoids from adrenal cortex (like cortisol)

Thyroid and Parathyroid Glands

• The Thyroid produces Thyroid hormone (TH)

  • Iodine is required to make TH-process stimulated by thyroid stimulating hormone (TSH)

  • Low TH results in goiters in adults

  • Low TH during early development causes developmental delays

  • Graves’ disease-an autoimmune condition with increased TH production-causes bulging eyes

• The Thyroid produces Calcitonin (CT)

  • Calcitonin (CT) helps regulate calcium concentration in the blood

  • When blood calcium is high, CT is released causing the bones to take up calcium

  • CT is most important during pregnancy and childhood

• Parathyroid glands secrete parathyroid hormone (PTH)

  • Parathyroid glands are small, round glands found on the back of the thyroid that secrete PTH

  • PTH increases blood calcium levels

  • When blood calcium is low, PTH secretion causes bones to release calcium and greater calcium reabsorption in the kidneys and intestines

  • Calcium levels return to normal

• Calcitonin and parathyroid hormone work together to keep calcium in balance

  • calcium is critical for proper nervous system function, muscle contraction, and bone density

  • Too much calcium in the blood also causes kidney stones!

Adrenal Glands

• The adrenal glands sit on top of each kidney

• The adrenal gland can be divided into adrenal cortex and adrenal medulla

• The adrenal cortex secretes more than 20 different hormones

• The adrenal medulla secretes epinephrine and norepinephrine

Adrenal Cortex Hormones

• Adrenal cortex hormones are mineralocorticoids, gonadocorticoids, or glucocorticoids

• Aldosterone is a mineralocorticoid that causes Na^+ reabsorption

• Cortisol is a glucocorticoid and “stress hormone”

• Prolonged cortisol release (chronic stress) can cause anxiety, depression, ulcers, etc.

Adrenal Medulla Hormones

• The adrenal medulla secretes epinephrine and norepinephrine

• Epi/norepinephrine are very similar and are released as part of the fight/flight system

• This is the sympathetic division of the autonomic nervous system

• The result of secretion is increased heart and respiratory rates

• Need to get oxygen and glucose to skeletal muscle to either fight or run away!

Pancreas

• The pancreas helps regulate blood sugar

• The pancreas sits behind the stomach

• In addition to digestive functions, the pancreas secretes the hormones insulin and glucagon to regulate blood sugar

• Insulin reduces blood sugar after a meal

  • As nutrients are absorbed after a meal, blood sugar rises

  • hyperglycemia-high blood sugar- causes increased thirst, increased urination, blurred vision, etc. in the short term-these are diabetes symptoms

  • Insulin prevents hyperglycemia by allowing sugar in the blood to enter muscle and fat cells

  • Glucose stored in muscle is glycogen

  • Glucose not stored as glycogen can be converted to fat

• Glucagon increases blood sugar by releasing energy stores

  • during periods of hypoglycemia-low blood sugar-glucagon is released

  • Glucagon increases blood glucose by breaking down glycogen stores in the liver

  • Glycogen storage gives us access to backup sugar when there is a long gap between meals

• Insulin and glucagon work together to balance blood sugar

  • glucose needs a transporter to cross the cell membrane

  • this transporter requires insulin

  • to get sugar into cells and lower blood sugar, insulin must be released

  • when blood sugar is too low, sugar reserves are tapped by using glucagon to break down sugars stored as glycogen

Hormone Function

Glands are specialized organs that secrete products.

Endocrine glands secrete hormones globally.

The endocrine system doesn’t include exocrine glands that secrete products locally. Exocrine glands secrete products into ducts and have local functions. Exocrine glands include oil glands, sweat glands, tear glands, salivary glands, milk glands, etc. Oil glands secrete oil into ducts that travels to surface of skin/hair for lubrication

Hormones are chemicals that cause a bodily response.

Hormones produced by glands are secreted into the bloodstream.

This leads to wide distribution of hormones

Hormones that make their way into the bloodstream can also remain active for a while

Hormone functions include regulating growth, metabolism, and sexual development

Hormone types include lipid-derived, amino acid-derived, and peptide hormones

Each hormone has a specific signaling job

Not every cell will respond to every hormone

Hormones interact with cells through specialized receptors that match up with that particular hormone

Increasing the number of receptors at the receiving cell can increase hormone sensitivity. Lesson 39.1 Figure 8

Summary:

The endocrine system is a hormone signaling system

Hormones contribute to development and homeostasis

Hormones cause cellular changes by binding to receptors at target cells

Hormone types include lipid-derived, amino acid- derived, and peptide hormones

Pituitary Gland

The pituitary gland is a small gland at the base of the brain in close association with the hypothalamus, sometimes referred to as the "master gland" because it regulates many other endocrine glands.

The pituitary gland can be divided into posterior/anterior regions each with their own hormones

Posterior Pituitary

The posterior pituitary secretes ADH

Antidiuretic hormone (ADH) is produced in the hypothalamus and stored for release in the posterior pituitary

ADH causes water reabsorption in the kidney

Water moves from kidney filtrate back to blood when blood water concentration is low, increasing blood volume and decreasing urine volume.

The posterior pituitary secretes Oxytocin

Oxytocin is produced in the hypothalamus and stored for release in the posterior pituitary

Oxytocin is released during breastfeeding, labor, and sexual activity

Receptors in a mother’s nipple are stimulated by a suckling infant and cause oxytocin release which stimulates milk ejection

Oxytocin is also involved in the positive feedback of contractions during childbirth: as the baby pushes on the cervix, more oxytocin is released, causing more contractions, pushing the baby further, until birth.

Anterior Pituitary

The anterior pituitary secretes six hormones

growth hormone

prolactin

thyroid stimulating hormone

follicle-stimulating hormone

luteinizing hormone

adrenocorticotropic hormone

Growth hormone promotes cell growth

Growth hormone promotes cell growth and division in bone, muscle, and cartilage. It also increases the use of fatty acids for energy.

Insufficient growth hormone during development causes pituitary dwarfism

Excess growth hormone during development can cause gigantism

Excess growth hormone in adulthood causes acromegaly-thickening of bones

Prolactin stimulates milk production

Pregnancy and nipple stimulation (suckling) increase prolactin levels

Prolactin stimulates milk production, but oxytocin triggers milk ejection from mammary tissue

Thyroid stimulating hormone stimulates synthesis of thyroid hormone

The thyroid is a gland in the front of the neck

It produces thyroid hormone when stimulated by thyroid stimulating hormone

Thyroid hormone has broad effects and helps regulate metabolism and blood pressure

Iodine is required for thyroid hormone synthesis

Thyroid stimulating hormone (TSH) stimulates production of thyroid hormones T3 and T4

If iodine levels are low, thyroid hormone cannot be produced

more TSH is released because thyroid hormone is still lacking

The thyroid becomes enlarged (goiters)

Follicle-stimulating hormone (FSH), Luteinizing hormone (LH), Adrenocorticotropic hormone (ACTH)

FSH promotes development of egg cells and estrogen secretion in females/maturation of sperm in males

LH causes ovulation in females/testosterone production in males

ACTH contributes to secretion of glucocorticoids from adrenal cortex (like cortisol)

Thyroid and Parathyroid Glands

The Thyroid produces Thyroid hormone (TH)

Iodine is required to make TH-process stimulated by thyroid stimulating hormone (TSH)

Low TH results in goiters in adults

Low TH during early development causes developmental delays

Graves’ disease-an autoimmune condition with increased TH production-causes bulging eyes

The Thyroid produces Calcitonin (CT)

Calcitonin (CT) helps regulate calcium concentration in the blood

When blood calcium is high, CT is released causing the bones to take up calcium

CT is most important during pregnancy and childhood

Parathyroid glands secrete parathyroid hormone (PTH)

Parathyroid glands are small, round glands found on the back of the thyroid that secrete PTH

PTH increases blood calcium levels

When blood calcium is low, PTH secretion causes bones to release calcium and greater calcium reabsorption in the kidneys and intestines

Calcium levels return to normal

Calcitonin and parathyroid hormone work together to keep calcium in balance

calcium is critical for proper nervous system function, muscle contraction, and bone density

Too much calcium in the blood also causes kidney stones!

Adrenal Glands

The adrenal glands sit on top of each kidney

The adrenal gland can be divided into adrenal cortex and adrenal medulla

The adrenal cortex secretes more than 20 different hormones

The adrenal medulla secretes epinephrine and norepinephrine

Adrenal Cortex Hormones

Adrenal cortex hormones are mineralocorticoids, gonadocorticoids, or glucocorticoids

Aldosterone is a mineralocorticoid that causes Na^+ reabsorption

Cortisol is a glucocorticoid and “stress hormone”

Prolonged cortisol release (chronic stress) can cause anxiety, depression, ulcers, etc.

Adrenal Medulla Hormones

The adrenal medulla secretes epinephrine and norepinephrine

Epi/norepinephrine are very similar and are released as part of the fight/flight system

This is the sympathetic division of the autonomic nervous system

The result of secretion is increased heart and respiratory rates

Need to get oxygen and glucose to skeletal muscle to either fight or run away!

Pancreas

The pancreas helps regulate blood sugar

The pancreas sits behind the stomach

In addition to digestive functions, the pancreas secretes the hormones insulin and glucagon to regulate blood sugar

Insulin reduces blood sugar after a meal

As nutrients are absorbed after a meal, blood sugar rises

hyperglycemia-high blood sugar- causes increased thirst, increased urination, blurred vision, etc. in the short term-these are diabetes symptoms

Insulin prevents hyperglycemia by allowing sugar in the blood to enter muscle and fat cells

Glucose stored in muscle is glycogen

Glucose not stored as glycogen can be converted to fat

Glucagon increases blood sugar by releasing energy stores

during periods of hypoglycemia-low blood sugar-glucagon is released

Glucagon increases blood glucose by breaking down glycogen stores in the liver

Glycogen storage gives us access to backup sugar when there is a long gap between meals

Insulin and glucagon work together to balance blood sugar

glucose needs a transporter to cross the cell membrane

this transporter requires insulin

to get sugar into cells and lower blood sugar, insulin must be released

when blood sugar is too low, sugar reserves are tapped by using glucagon to break