Ch21 endocrine

What is the definition of a hormone?

Substances that are secreted by one group of cells that affects the physiology of another group of cells

What can hormones be made from?

Amino acids, proteins or polypeptides, or cholesterol.

Compared to most other organs in the body, are endocrine organs well vascularized?

Yes

Why are hormones able to maintain homeostasis?

because they are subject to negative feedback mechanisms

How can very few molecules of a hormone effect changes in a target cell?

because the mechanism of hormonal action involves an enzyme cascade that amplifies the response to a hormone

Which gland is a major source of steroid hormones in the body?What part of that organ secretes the steroids?

Adrenal gland, cortex region Adrenal cortex

Tumor of the pituitary gland can lead to what?

Blindness

Trauma to the pituitary gland can lead to what?

Diabetes insipidus

They pituitary gland is attached to the hypothalamus by what structure?

The infundibulum

What are the two parts of the pituitary gland?

Adenohypophysis is the anterior pituitary. Neurohypophysis is the posterior pituitary.

What are the seven hormones secreted by the adenohypophysis (anterior pituitary)

Growth hormone (GH):Prolactin (PRL):Thyroid stimulating hormone (TSH):Adrenocorticotropic hormone (ACTH):Melanocyte-stimulating hormone (MSH):Follicle-stimulating hormone (FSH):Leutenizing hormone (LH)

What is a study tip to remember the hormones secreted by the anterior pituitary?

Melons Grow And Produce Through Late Fall = MSH, GH, ACTH, PL, TSH, LH, FSH

What are the Pituitary Gonadotropins?

FSH and LH are called gonadotropins because they act on the gonads. They regulate reproductive function

What two hormones are secreted by the neurohypophysis (posterior pituitary)? | What are their functions?

Oxytocin: stimulates childbirth contractions ADH: increases blood volume (no salt involved)

Which hormone induces milk production and may produce the desire to cry?

Prolactin

What is essential for the formation of thyroxin?

Iodine

What pituitary disorders are involved with hypersecretion of GH in children, overall growth

Gigantism

Oversecretion of growth hormone which starts in ADULTHOOD causes what disorder?

Acromegaly

What is Acromegaly?

Enlarged hands and feet

What disorder is Hyposecretion of GH, resulting in normal proportion of head and limbs; overall size is small?

Pituitary dwarfism

Where is ADH secreted?

Pituitary gland (posterior portion)

What disorder is a result of not enough ADH?(anti-diuretic hormone; a diuretic takes out excess fluid from the body)

Diabetes insipidus

What are the 2 hormones produced by the thyroid gland?

Thyroid hormone and calcitonin

What does thyroid hormone do?

Increases metabolic rate

What does calcitonin do?

Lowers blood calcium

What hormone raises blood calcium?

Parathyroid hormone

How does calcitonin lower blood calcium?

Slows osteoclasts to allow for bone deposition (good for children). It does not increase intestinal calcium absorption.

The major stimulus for the release of thyroid hormone is by what mechanism?

Hormonal

What are the 3 ways that parathyroid hormone raise blood calcium levels?

1) Stimulates osteoclasts to move bone calcium into bloodstream (increases calcium resorption from bone). 2) Stimulates the intestines to absorb more calcium from the diet 3) Stimulates the kidneys to stop excreting calcium.

Parathyroid hormone is released by what mechanism?

Humeral Mechanism

Where is vitamin D synthesized?

In the dermis

What problem with the thyroid is due to little iodine in the diet?

Goiter

What disorder is caused by an autoimmune disorder which leads to nervousness, weight loss, sweating, increased metabolic rate, rapid heart rate, and increased mental alertness?

Hyperthyroidism

What disorder decreases metabolism and causes obesity?

Hypothyroidism

Hormones produced by this organ stimulate the production of t cells

Thymus gland

What glands sit on top of each kidney?

Adrenal gland

Adrenal cortex secretes what three steroids?

Cortisol Aldosterone Sex hormones for the opposite sex: males produce estrogen here, and females produce testosterone.

What hormone helps the body cope with stress?

Cortisol

What hormone raises blood pressure by increasing salt reabsorption?

Aldosterone

What hormone increases blood volume without increasing salt retention (no slat involved)?

ADH

Adrenal medulla secretes which hormones?

Epinephrine and norepinephrine

Hypersecretion of cortisol and a round "moon" face and "buffalo hump" are characteristic of what disorder?

Cushing’s disease

Hyposecretion of cortisol, increased blood ACTH levels, low blood volume and pressure, and increased skin pigmentation are characteristics of what disorder?Note: blood glucose levels are normal or may be low.

Addison’s disease

What is an example of a mineralocorticoid?

Aldosterone

What is an example of a glucocorticoid?

Cortisol

What is the function of glucocorticoids?

1) They increase fat catabolism (lipolysis) and protein catabolism to use for gluconeogenesis. 2) They increase blood glucose concentration. 3) They decrease the inflammation response

What does the pineal gland secrete?

Melatonin-A hormone that regulates circadian rhythms (sense of daytime and night ; it regulates sleep cycle)

Which endocrine gland stands out in x-ray images and helps radiologists get oriented in the brain?

Pineal gland

What cells make the pancreas an exocrine gland, and what do they secrete? | What cells make the pancreas an endocrine gland, and what do they secrete?

Exocrine: acinar cells secrete digestive enzymes into a duct. Endocrine: islets of Langerhans secrete insulin and glucagon directly into the blood.

What signals the liver to release glucose from glycogen and raises blood sugar?

Glucagon

What signals most body cells to take up glucose from glycogen from the blood, promotes storage of glucose as glycogen in the liver, and lowers blood sugar?

Insulin

What disorder is when the pituitary gland does not secrete antidiuretic hormone, or the kidney does not respond to it?

Diabetes insipidus ; can also be caused by damage to the pituitary or kidney damage.

What are the 2 types of diabetes mellitus?

Type I (insulin dependent, develops in children) Type II (insulin resistance, develops in adults)

Which type of diabetes is insulin dependent because the people do not make their own insulin?

Type I diabetes (insulin dependent, develops in children) is more serious. It is caused by destruction of pancreatic islets by autoimmune disorders. They must have insulin injections daily throughout life.

How does a person get type II diabetes?

It is a consequence of obesity. They produce insulin, but their cells are less sensitive to the effects of insulin

How is type II diabetes treated initially?

Diet and exercise

What two hormones do the ovaries secrete?

Progesterone and estrogen

What does estrogen do?

Creates secondary sex characteristics in the female

What does progesterone do?

Prepares uterus for pregnancy by causing enlargement of arteries supplying blood to the endometrium and growth of endometrial glands

What is the primary sex organ in the male?What does it secrete?

Testes, not penis Testosterone is produced in the testes of males and in the adrenal gland of both sexes.

What is the only thing that does not make hormones?Why?

Epithelial duct cells (they are exocrine glands) Because all exocrine glands secrete into a duct, and the definition of a hormone is one that does not secrete into a duct ; it secretes into the blood, where it is transported elsewhere in the body and has its effect there.

What is glycogen?

The storage form of glucose. When glucose is in excess, it is taken to the liver and converted into glycogen, and stored there.

When will glycogen be broken down?

When blood glucose is low

What does parathyroid hormone do?

Causes the intestines and kidneys to absorb more calcium, and tells the osteoclasts to degrade bone to increase blood calcium levels.

When the hypothalamus (the boss) releases TSH-RH, what happens to the pituitary gland (the manager)?

Pituitary gland releases TSH (thyroid stimulating hormone)

What effect does that have?

TSH causes the thyroid gland (the worker) to secrete TH (thyroid hormone)

What are the functions of TSH?

Increases iodine trapping in follicular cells, increased Thyroglobin synthesis, increased release of T3 and T4, and increased iodination of thyroglobulin

In an under-secreting thyroid tumor will TH be high or low? | Will TSH-RH be high or low? | Will TSH level be high or low? | What might cause the above condition?

Low High High Goiter caused by iodine deficiency

In an over-secreting thyroid tumor will TH be high or low? | Will TSH-RH be high or low? | Will TSH levels be high or low?

High Low Low

In an under-secreting pituitary tumor will TSH be high or low? | Will TH be high or low? | Will TSH-RH be high or low

Low Low High

In an over-secreting pituitary tumor will TSH be high or low? | Will TH be high or low? | Will TSH-RH be high or low?

High High Low

In an under-secreting hypothalamic tumor will TSH-RH be high or low? | Will TSH be high or low? | Will TH be high or low?

Low Low Low

In an over-secreting hypothalamic tumor will TSH-RH be high or low? | Will TSH be high or low? | Will TH be high or low?

High High High

What is the functional unit of the thyroid gland?

The thyroid follicle

What is Graves’ disease?

Autoimmune disease that causes hyperthyroidism. There is increased TH, and decreased TSH-RH and TSH

What are the hormone levels in Graves’ disease (hyperthyroidism from oversecreting thyroid)?

TH high, TSH-RH and TSH low

What are the hormone levels in Hashimoto’s thyroiditis (hypothyroidism from undersecreting thyroid)?

TH LOW, TSH-RH AND TSH HIGH.

What are the hormone levels in an oversecreting hypothalamic tumor?

TSH-RH is high, TSH is high, TH is high.

What drug can be used for people who have Graves’ disease?

PTU (propylthiouracil)

What would happen to TSH-RH, TSH, and TH in the following conditions: | Antibodies attacking thyroid gland, destroying the gland | Antibodies binding to the TSH receptor, stimulating it

-TH LOW, TSH-RH AND TSH HIGH - TH AND TSH HIGH, TSH-RH LOW

When TH stimulates neurons a person feels what? | Not enough TH? | Too much TH?

Feels more alert, observing their environment with more interest They lose interest, become sluggish, hypoglycemia They get muscles tremors and hyperglycemia

When blood sugar is high, what hormone is released by the pancreas and what does it do?

Insulin is released, tells the cells to take in the sugar from the bloodstream.

What if there is more sugar in the blood than the cells can use? Where does the excess sugar go?

Excess sugar is taken to the liver and converted to glycogen for storage

When blood glucose is low, what hormone is released by the pancreas and what does it do?

Glucagon tells the liver to take the glycogen and break it back down into glucose and release it into the bloodstream.

Describe the process of gluconeogenesis

The liver takes fatty acids (leftover from fat metabolism) and joins them to amino acids (from broken down proteins), and makes new glucose molecules that you did not get from eating glucose. These new glucose molecules are then released into the bloodstream to elevate blood glucose levels.

Blood glucose levels that are too high are called? | Low blood glucose is called what?

Hyperglycemia Hypoglycemia

During hyperglycemia, what hormone is released? | What gland releases it? | What is its effect on the blood sugar levels?

Insulin Pancreas Lowers blood sugar

During hypoglycemia, what hormone is released? | What gland releases it? | What is its effect on the blood sugar levels?

Glucagon Pancreas Raises blood sugar

What two processes raise blood sugar?

Gluconeogenesis and glycogenolysis (glycogen breakdown). Note: glucagon is released during both of these processes.

Hyperthyroidism is most commonly caused by what disease?

Graves’ disease

What are the signs of Graves’ disease?

Thin person with eyes that stick out like a bug (exophthalmoses).

What causes Graves’ disease? What effect does graves’ disease have on TH levels? On TSH? On TSH-RH?

It is an autoimmune disease Increased TH Decreased TSH-RH AND TSH

What 4 things can cause hypothyroidism?

Hashimoto’s thyroiditis (autoimmune) Iodine deficiency Thyroid tumor, under-secreting Defective thyroid enzyme(s)

What is the medical term for a goiter?

Thyromegaly

What does idiopathic mean? | What does iatrogenic mean?

Idiopathic = unknown cause Iatrogenic = medical treatment caused the condition

What is cretinism?

A baby with hypothyroidism because the mother had a lack of iodine.

What is the mental status of cretinism?

Mental retardation

If you give a cretinism baby a healthy diet, will it improve? Why?

No, because TH was not present during fetal development, when myelination and synaptic formation needed it.

What condition is when a baby's thyroid gland is not secreting enough thyroid hormone? | Is it a problem with the baby or the mother?

Congenital hypothyroidism This is a problem with the baby, not the mother.

What is the difference between congenital hypothyroidism and cretinism?

In cretinism, the problem is with the mother’s thyroid gland, not the baby