PSL 310 endocrine system

Describe how vitamin D Increases Ca++ absorption from food in the gut.

It causes synthesis of Ca++ binding proteins and Ca++ pump proteins on the brush border cells of the small intestine which increases Ca++ absorption in the gut.

Describe hypocalcemic tetany and why it happens.

involuntary muscle contractions. Happens because low blood Ca++ causes the membrane to be leaky to Na+.

why is iodine a necessary nutrient

iodine must be supplied in the diet to make T4. it is the only reason you need it.

thyroglobulin

large protein which contains thyroid hormones. Store thyroid hormones.

List the hydrophilic hormones.

peptide hormones and catecholamine's.

Long feedback loop

refers to the hormone that was released from the peripheral endocrine glands inhibiting pituitary and/or hypothalamic secretion of releasing hormones.

List the lipophilic hormones.

steroid and thyroid hormones.

target cells

the hormones site of action, the cell hormones influences.

Identify aldosterone as the important mineralocorticoid from the adrenal complex.

the important mineralocorticoid from the adrenal cortex.

Describe the neural link between the neurohypophysis and the hypothalamus

the neurohypophysis is connected by a stalk to the hypothalamus.

T3

thryoxine

Describe why it is good to be careful with glucocorticoid therapy.

At high doses, therapeutically a patient can get Cushing's syndrome.

Source of calcitonin

from cells between the follicles of the thyroid gland.

Short feedback loops

generally, refers to a pituitary hormone providing negative feedback to the hypothalamus, inhibiting secretion of the releasing hormone

Explain the steps of thyroid hormone synthesis and release.

1. Follicle cells make thyroglobulin which is secreted into the colloid. 2. Iodide is cotransported into the follicle cells with NA+. 4. Iodide enters the colloid. 6a. MIT (one iodine) and DIT (2 iodine) make T3. 6b. DIT and DIT make T4 7. Endocytosis of thyroglobulin by follicle cells. 8. Lysosomal enzymes break apart thyroglobulin.

Define mitogen and list one

A chemical that causes cell division. Insulin like growth factor I is an example.

List the anterior pituitary tropic hormones

ACTH: controls secretion of cortisol from the adrenal cortex TSH: stimulates secretion of thyroid glands thyroid hormones. Also stimulates thyroid gland to grow. FSH and LH: cause sex hormone secretion from the gonads and gamete development.

Describe the 2 hormones secreted from the neurohypophysis, where they're made, and what triggers their release.

ADH: vasopressin Oxytocin: stimulates uterine contractions in delivery of baby. Also, is the hormone for milk letdown.

Describe the signal transduction or post receptor binding events of hydrophilic hormones that use cAMP as a second messenger.

Adenyl cyclase is activated, adenyl cyclase make cAMP from ATP, cAMP activates a protein kinase, the kinase phosphorylates/activates proteins, activated protein causes the response dictated by hormone.

Describe TSH's effect on thyroid hormone synthesis and release.

Almost all of the steps of synthesis and release of thyroid hormones are controlled by it.

Of the kinds of dwarfism to know, what is the usual cause?

An issue with the anterior pituitary

Realize growth hormone and prolactin have a dual control and that one releasing hormone controls two anterior pituitary hormones

Both releasing and inhibiting hormones control these two anterior pituitary hormones. Gonadotropin releasing hormone controls LH and FSH.

List the releasing and inhibiting hormones from the hypothalamus

CRH, TRH, GHRH, GHIH, PIH, PRH, GnRH

Describe the effects of hypersecretion of adrenal androgens and the treatment.

Can cause bearded lady or masculinization of a young child. Due to an enzyme deficit.

Describe over secretion of growth hormone- if occurs before or after the epiphyseal plate ossifies.

Cause gigantism

Colloid

in the follicles. Mostly thyroglobulin but there are also enzymes.

Describe Cushing's syndrome.

Caused by high levels of cortisol. Symptoms include "moon face" and buffalo hump" due to fat mobilization and stretch marks on skin.

Describe growth hormones effects- anti-insulin, protein synthesis, growth

Causes anti-insulin effects on metabolism. Causes increase protein synthesis Causes increase growth

Explain the role of insulin-like growth factor I on growth hormones effect on growth.

Causes mitosis or cell division.

Explain which cells responds to a particular hormone and why.

Cells only respond to a certain hormone if they have receptors for the hormone.

Define portal vessel

Connects two capillaries.

Identify the important glucocorticoid from the adrenal cortex

Cortisol

Describe the effect cortisol has on catecholamine vasoconstriction and what can happen to a patient with low cortisol with stress that requires vasoconstriction

Cortisol allows increased vasocontraction. If a patient with low cortisol has stress that requires vasocontraction they die.

Explain the anti-insulin effects on cortisol.

Cortisol increases gluconeogenesis, fat catabolism, and protein catabolism, and therefore increase blood glucose, fatty acids, and amino acids.

Describe what happens when a factor like stress moves the set point up.

Cortisol secretion will increase with stress. Still have negative feedback, but will oscillate around a higher set point.

Describe cretinism and how to prevent it.

Deficiency of thyroid hormone in infancy which causes mental retardation. Tested at birth and then treated with TH.

Describe the milk letdown reflex and what can affect it.

Ejection of milk into the ducts of the breast so that they baby can remove it by suckling. Psychological stress can affect the milk letdown reflex. Worrying about not being able to nurse may prevent the reflex or hearing someone else's baby cry may cause a nursing mother to leak.

Describe a goiter and how it happens with an iodine deficiency and explain why TSH and TRH secretion would be high.

Goiter: enlarged thyroid gland which happens with iodine deficiency. There is a lack of negative feedback so that is why you have an increase of TSH and TRH.

Describe why there were goiters in the great lakes areas. Was cretinism also present?

Goiters because there isn't much iodine in the soil. Cretinism was also present.

what is the stimulus for release of calcitonin

increased blood Ca++ causes increased calcitonin which decreased blood Ca++.

List which hormones are released from the anterior pituitary

Growth hormone and prolactin.

Describe the pituitary gland.

Has an anterior (adenohypophysis) that grows upward and posterior part (neurohypophysis) which develops as a downward growth of the hypothalamus.

Describe this portal vessel that reaches the anterior pituitary and two other portal vessels in the body

Hormones can be directly picked up in the capillaries of the hypothalamus and be directly delivered to the anterior pituitary.

Define hypophysiotropic hormones and describe the way they reach the anterior pituitary.

Hormones from the hypothalamus which control the anterior pituitary. Capillaries in the hypothalamus lead to hypothalamus-pituitary portal vessel which pass down the pituitary stalk lead to capillaries in the anterior pituitary.

Describes acromegaly.

Hypersecretion of a hormone in adulthood resulting in bone thickness. Large jaw and forehead

Describe the undersecreton of growth hormone as cause of dwarfism.

Hyposecretion of GH (from the anterior pituitary) is a cause of dwarfism.

Describe the anterior pituitary's relationship with the hypothalamus.

Hypothalamus secrets hormones which control anterior pituitary hormone secretion.

Describe other 2nd messengers beside cAMP.

IP3 and DAG.

Describe how calcitonin is used clinically.

In a nasal spray or treatment for osteoporosis.

where is T4 converetd to T3?

In the tissues

Explain the effect of increased ACTH on cortisol secretion.

Increased ACTH means increased cortisol.

hyper active thyroid on BMR and weight

Increased BMR, decreased weight

Explain negative feedback regulation of hormone secretion using cortisol as an example.

Increased CRH, increased ACTH, increased cortisol

Explain the effect of thyroid hormones on beta receptors in the heart.

Increases the number of beta receptors on the heart.

Describe the effect on heat production.

Iodine deficiency can cause increased thyroid hormone which means increased heat production with increase BMR

Describe the pharmacological effects of cortisol as anti-inflammatory and immune suppressing drugs and that some of these effects may also occur at levels of cortisol in the body during stress.

Limits the inflammation/ immune response so it doesn't get out of hand.

Explain why plasma Ca++ levels must be regulated and why removal of the parathyroid glands will cause death.

Low blood Ca++ cause hypocalcemic tetany with spontaneous tetanic muscle contractions. It affects the respiratory muscles and can cause death.

Explain why continual nursing is needed for milk production.

Need pulses of prolactin release and removal of the milk from the breast to keep the milk being produced.

Describe PTHs effect on the kidney

increased reabsorption of Ca++ and decreased reabsorption of PO43- and increase PO43- excretion. It decreases the possibility of precipitation of 2 ions together.

effect of calcitonins

inhibits osteoclasts

Compare how the importance of calcitonin with parathyroid hormone in normal control of blood Ca++.

Not an important controller of blood Ca++. The role in humans is still a mystery.

list which anterior pituitary hormone is not a tropic hormone.

Prolactin

Describe prolactin effects and why oxytocin is also needed for nursing.

Prolactin: promotes lactation; also promotes breast gland development. Oxytocin is needed to get milk into the ducts.

Describe exemptions to the general rule of how lipid soluble/lipid insoluble hormones cause responses.

Researchers are finding that some lipid soluble hormones can use membrane receptors and activate second messengers to have effects not due to not turning on or off genes and some lipid soluble hormones activate genes.

Why is iodine added to salt?

Salt is something everybody ingests and is a way to get iodine.

Explain when cortisol secretion increases and how is important in adaption to stress.

Secretion increases to stress. It helps resist stress.

Describe sex hormone release from the adrenal cortex and the function in the female.

Sex hormones are released from the adrenal cortex in small amounts. The androgen is responsible for the pubic and axillary hair and sex drive in females.

Describe the chemical structure of hormones as presented in lecture.

Steroids: ringed lipids derived from cholesterol- sex hormones and adrenal cortex hormones. Peptides: chains of amino acids- most hormones. Amines: from the amino acid tyrosine.

Describe "milk letdown" generally as a neuroendocrine reflex.

Suckling causes impulses to go to the brain to the hypothalamus to the posterior pituitary- causes oxytocin to release. Oxytocin travels in the blood to the breast and causes contraction of myoepithelial cells. Causes milk let down.

Describe why some patients died in early thyroid surgeries and what is done today in thyroid surgeries to prevent death after the surgery.

Surgeons would remove all of the parathyroid gland with the thyroid and those patients died of hypocalcemic tetany. Today surgeons leave some parathyroid tissue.

which is more potent T3 or T4

T3

Is there more T4 or T3 in the body

T4

Describe the effects of thyroid hormones on overall growth and growth and development of the nervous system.

TH promotes effects of growth hormones and is needed for nerous system growth and development.

Describe the hormones from the hypothalamus as tropic hormones.

The hypothalamic releasing and inhibiting hormones are called hypophsyiotropic hormones. Their target is an endocrine gland= anterior pituitary

Identify which is really the master, the pituitary or the hypothalamus.

The hypothalamus is really the master because it controls the pituitary secretions.

Describe the interrelation of the nervous and endocrine systems.

The hypothalamus is the link between the 2 systems because it controls the pituitary gland.

Compare the effects of the nervous system to the endocrine system.

The nervous system is faster acting but its effects are shorter lasting than hormones.

Define tropic hormones.

The rest of the anterior pituitary hormones.

Describe the general types of responses caused by hormone binding to receptors, and generally which type of hormone will cause each of those responses.

The signal transduction causes the response. Lipid soluble hormones: could activate genes. Lipid insoluble hormones: act as a second messenger.

Describe the colloid as a storage for thyroid hormones.

There is a quantity of thyroid hormone in the colloid- about 3 month's worth

Describe parathyroid hormone- its importance in blood Ca++, source, effect, and stimulus for release.

Very important in controlling blood Ca++. Source: From parathyroid glands. Effect: PTCH increases blood Ca++. Stimulus for release: decreased Ca++ in the blood.

Explain why vitamin D is really a hormone and the skin is an endocrine gland.

We can make it in the body so it's really a hormone. The skin is an endocrine gland because we can make vitamin in our skin with sunlight.

Explain when growth hormone is considered a tropic hormone.

When it stimulates IGF-I release from the liver.

how are the thryoid hormones released?

When thyroglobulin is split up by enzymes, the thyroid hormones are released.

Describe the effect of thyroid hormones on cells responsiveness to catecholamine's.

With increased thyroid hormones, there is an increased responsiveness to catecholamine's.

Explain what causes the enlargement of the thyroid gland due to low iodine.

You get an enlarged thyroid gland because TSH stimulates the thyroid gland to grow.

Follicle

a ball of cells. Filled with colloid. Secrete colloid.

Identify when IGF-I a is a autocrine agent

affects the cell that released it

Lipid soluble hormones

can get through the cell membrane so receptors are inside the cell. Lipophilic.

Lipid insoluble hormones

can't get through the cell membrane so receptors are on the outer surface of the membrane. Hydrophilic.

Describe PTHs effect on bone

causes a release of Ca++ from bone, stimulates cells that tear down bone.

Hypo active thyroid on BMR and weight

decreased BMR, increased weight

Describe other causes of dwarfism.

decreased production of IGF-1. Decreased responsiveness to growth hormone due to abnormal growth hormone receptors

Endocrine glands

ductless glands. They secret hormones into the blood which effect target cell action

Decribe PTHs effect on the intestines

effect is indirect through vitamin D. The step-in activation of vitamin D in the kidney is stimulated by PTH.

T4

triiodothyrnine

Thyroid gland

two lobes connected. Composed of follicles filled with colloid

Identify when IGF-I a is a hormone

when it is released by the liver.

Identify when IGF-I a is a paracrine

when its released by other cells and affects nearby cells.