A&P Endocrine System

Target cell activation depends on 3 factors

1. Blood levels of hormone 2. Relative number of receptors on/in target cell 3. Affinity of binding between receptor and hormone

Hormones are removed from the blood by

1. Degrading enzymes 2. kidneys 3. Liver

cAMP signaling mechanism

1. Hormone (First messenger) binds to receptor 2. Receptor activates G protein 3. G protein activates adenylate cyclase 4. Adenylate cyclase converts ATP to cAMP (second messenger) 5. cAMP activates protein kinases that phosphorylate proteins

Dehydration and low blood pressure can be fixed with

ADH

Diabetes insipidus

ADH deficiency due to hypothalamus or posterior pituitary damage

NOT synthesized in the pituitary gland??

ADH, ADH is made in the hypothalamus

_______cells produce glycoprotein Thyroglobulin

Follicular

what is the function of the endocrine system

Functions with the nervous system to maintain homeostasis

Sensory stimulus, hypothalamus, posterior pituitary, oxytocin, myoepithelial cells of mammary gland, milk "let down"

Oxytocin is released in high amounts during childbirth and nursing women due to the sensory stimulus on the cervix. The prolactin cells during this time stimulate milk letdown. When the uterus stretches during childbirth, prolactin is then released by the posterior pituitary gland. The hypothalamus plays a big part because it secrets oxytocin and releases neurohormones which are made from the hypothalamus.

Which of the following signals would affect local cells by releasing chemicals into the extra cellular fluid

Paracrine

Tetany, blood calcium levels, synapses, PTH, parathyroid glands

Parathyroid hormone (PTH) controls blood calcium levels. If blood calcium levels drop too low, this can result in symptoms of Tetany, a condition marked by sporadic muscle spasms. They are caused by the malfunction of the parathyroid gland which cause a deficiency of blood calcium levels. This causes muscle twitches and convulsions because the impulses travel across the synapse at irregular, sporadic times to the neurotransmitter. The neurotransmitter is released at inappropriate times causing the "spasms."

Importance of mineralocorticoids

Regulate electrolyte concentration in blood (K and Na) Most prevalent one is aldosterone

2 primary sources for aldosterone

Renin-angiotensin (aldosterone mechanism) and Plasma concentration of potassium

Up-regulation

Target cells form more receptors in response to low hormone levels

Down-regulation

Target cells lose receptors in response to high hormone levels

FSH

a. Source: Anterior pituitary b. Chemical Nature: Amino acid c. Transport in the blood stream: free, meaning it doesn't need a carrier d. Mechanism of action: Plasma membrane bound e. Target cell or tissue: Ovaries and testes f. Effect: Stimulate release of reproductive hormones g. Neural, hormonal, humeral: Hormonal Hypersecretion: No important effects Hyposecretion: Failure of sexual maturation

ACTH

a. Source: Anterior pituitary b. Chemical Nature: Amino acid c. Transport in the blood stream: Free, does not need a carrier d. Mechanism of action: Plasma membrane e. Target cell or tissue: Adrenal cortex f. Effect: Resists stressors (your stress response) g. Neural, hormonal, humeral: Hormonal Hypersecretion: Cushing's disease Hyposecretion: Rare

Prolactin

a. Source: Anterior pituitary gland b. Chemical Nature: Amino acid c. Transport in blood stream: Free, water soluble, does not need a carrier d. Mechanism of action: Plasma membrane receptor b/c it cannot enter the cell on its own e. Target cell or tissue: Mammary glands f. Effect: Milk production g. Neural, hormonal, humoral: Hormonal Hypersecretion: Inappropriate milk production; termination of blood discharged from the uterus; impotence in males Hyposecretion: Poor milk production in nursing women

ANP

a. Source: Heart b. Chemical nature: Amino acid c. Transport in the blood stream: Free, meaning it doesn't need a carrier d. Mechanism of action: Plasma membrane bound e. Target cell or tissue: Kidneys f. Effect: generates sodium loss and lowers blood volume g. Neural, hormonal, humeral: Humeral

LH

a. Source: In the anterior pituitary b. Chemical Nature: Steroid c. Transport in blood stream: Needs a carrier d. Mechanism of action: Nuclear receptor e. Target cell or tissue: Ovaries and testes f. Effect: Triggers ovulation and promotes testosterone production g. Neural, hormonal, humoral: Hormonal Hypersecretion: No important effects Hyposecretion: Failure of sexual maturation

ADH

a. Source: Made in Hypothalamus. released by Posterior Pituitary b. Chemical Nature: Amino acid c. Transport in blood stream: Does not need a carrier, it is free d. Mechanism of action: Plasma membrane receptor e. Target cell or tissue: Kidney tubule cells f. Effect: Water reabsorption g. Neural, Hormonal, Humoral: Neural Hypersecretion: Causes diabetes Hyposecretion: Casues edema

Insulin

a. Source: Pancreas b. Chemical Nature: Amino acid c. Transport in the blood stream: Free, does not need a carrier d. Mechanism of action: Plasma membrane e. Target cell or tissue: Blood and cells throughout the body (muscle and fat cells) f. Effect: Lowers blood glucose levels g. Neural, hormonal, humoral: Humoral Hypersecretion: Nervousness, anxiety, hypoglycemia, tremors Hyposecretion: Diabetes, polyuria, polydipsia

Parathyroid

a. Source: Parathyroid Gland b. Chemical Nature: amino acid c. Transport in the blood stream: Free, water soluble, does not need a carrier d. Mechanism of action: Plasma membrane e. Target cell or tissue: Muscle, nerve, and blood f. Effect: Increases calcium blood levels g. Neural, hormonal, humoral: Humoral Hypersecretion: Formation of kidney stones, depression of the nervous system Hyposecretion: Tetany

Melatonin

a. Source: Pineal Gland b. Chemical Nature: Amino acid c. Transport in blood stream: Water soluble, does not need a carrier d. Mechanism of action: Plasma membrane receptor e. Target cell or tissue: The suprachiasmatic nucleus f. Effect: Makes you sleepy g. Neural, Hormonal, Humoral: Neural Hypersecretion: You're more tired Hyposecretion: You cannot get sleepy

Oxytocin

a. Source: Posterior Pituitary gland b. Chemical nature: Amino acid c. Transport in blood stream: Free, water soluble, does not need a carrier d. Mechanism of action: Plasma membrane receptor e. Target cell of tissue: Mammary glands and uterus f. Effect: Milk production and uterine contractions g. Neural, hormonal, humoral: Neural Hypersecretion: Unknown Hyposecretion: Unknown

Cortisol

a. Source: Zona fasiculata b. Chemical Nature: Steroid c. Transport in blood stream: Bound to plasma proteins d. Mechanism of action: Nuclear receptor e. Target cell or tissue: Most body cells f. Effect: Provoke gluconeogenesis g. Neural, Hormonal, Humoral: Humoral Hypersecretion: Addisons disease Hyposecretion: Cushing syndrome

Gonadocorticoids

a. Source: Zona reticularis b. Chemical Nature: Steroid c. Transport in blood stream: bound (Needs a carrier) d. Mechanism of action: Nuclear receptor e. Target cell or tissue: Testes and ovaries f. Effect: Testosterone production and ovulation in ovaries. g. Neural, hormonal, humoral: Hormonal Hypersecretion: Masculinization in females Hyposecretion: no known effects

Aldosterone

a. Source: Zono glomerulosa b. Chemical Nature: Steroid c. Transport in the blood stream: Bound, meaning it needs a carrier d. Mechanism of action: Nuclear receptor e. Target cell or tissue: Kidneys f. Effect: Sodium reabsorption and Potassium elimination g. Neural, hormonal, humeral: humoral

Eicosanoids are not true hormones because they

act locally

Loss of sodium from extracellular fluids can be fixed with \

aldosterone

The hypophyseal portal system transports releasing and inhibiting hormones from the hypothalamus to the

anterior pituitary gland

Thyroid gland secretes

calcitonin

high blood sugar levels can be fixed with

insulin

The hypothalamus makes neural hormones____

Oxytocin and ADH (both are composed of 9 amino acids)

Could any hormone that increases blood glucose levels hypothetically result in pancreatic burnout and/or downregulation of insulin receptors on target cells and therefore diabetes mellitus?

Yes, if too much glucose is released in blood, the pancreas will have to work very hard and release maximum outputs of insulin to keep the glucose level normal. If the pancreas is overworked, it can stop functioning 100 percent which could lead to Diabetes mellitis Which is the hypoactivity of insulin.

Top layer of the adrenal cortex

Zona Glomerulosa: Produces mineralocorticoids

Middle layer os the adrenal cortex

Zona fasiculata: Produces glucocorticoids

Lowest layer of the adrenal cortex?

Zona reticularis: Produces sex hormones and gonadocorticoids

The hypothalamus is also considered

a neuroendocrine gland

Catecholamine

a. Source: Adrenal medulla b. Chemical nature: Amino acid c. Transport in blood stream: Free, water soluble, does not need a carrier d. Mechanism of action: Plasma membrane receptor e. Target cell or tissue: Sympathetic nervous system f. Effect: SNS activation g. Neural, hormonal, humoral: Neural Hyposecretion: Unimportant Hypersecretion: Prolonged fight-or-flight

Exocrine glands

Have ducts and are associated with sweat and saliva (non hormonal substances)

What is the hypophyseal portal system

A system of blood vessels in the brain that connects the hypothalamus with the ANTERIOR pituitary. It transports and exchanges hormones rapidly

Membrane receptor, hormone, adenylate cyclase, ATP, cyclic AMP, protein kinase enzyme, cascade reaction, hormone action

A Hormone is a chemical messenger that enables communication between cells. Hormone action is where hormones are released into the blood stream, and are carried through the body where they reversibly bind to their target receptors. The Hormone (first messenger) binds to the membrane receptor. The receptor activates the G protein. The G protein activates adenylate cyclase. Adenylate cyclase converts ATP to cAMP (second messenger). cAMP activates protein kinases that phosphorylate proteins. Activated kinases phosphorylate various proteins, activating some and inactivating others. cAMP is rapidly degraded by enzyme phosphodiesterase. Intracellular enzymatic cascades have huge amplification effect.

Permissiveness

A hormone cannot exhibit its full effect without another hormone

Aldosterone, Na+ levels in blood stream. blood volume, water reabsorption, blood pressure

Aldosterone is a hormone produced by the zona glomerulosa in the adrenal cortex. It regulates Na+ reabsorption and K+ secretion by the kidneys. Aldosterone reduces excretion of Na+ from the body. Its primary target is the distal parts of the kidney tubules, where it stimulates Na+ reabsorption and water retention accompanied by elimination of K+ and, in some instances, alterations in the acid base balance of the blood ( by H+ excretion). Decreasing blood volume and blood pressure, and rising blood levels of K+, stimulate aldosterone secretion. The reverse conditions inhibit its secretion.

What are the two major sources of tropic hormones? Name the tropic hormones from these sources and the direct action of each hormone.

Anterior pituitary gland and the hypothalamus. The hypothalamus sends a chemical stimulus to the anterior pituitary gland to signal the release of one or more hormones. - 4 of the 6 anterior pituitary hormones (thyroid stimulating, adrenocorticotropic, follicle stimulating, luteinizing hormones) are tropic hormones

What hormones, if deficient, can result in excess water loss? Explain.

Antidiuretic hormone stimulates the kidney tubule cells to reabsorb water. Hyper secretion causes you to absorb too much water and hyposecretion causes you to not absorb enough -Aldosterone causes the absorption of water by increasing levels of sodium and potassium ions in the blood

Steroid hormones influence cellular activities by

Binding to DNA and forming a gene-hormone complex

Parafollicular cells produce

Calcitonin

Parathyroid hormone controls?

Calcium balance in the blood

Autocrines

Chemicals that affect the same cells that produce them

The hormone response element is located in the _________ of the cell

DNA

Humoral

Endocrine glands secrete their hormones in direct response to changing blood levels of certain critical ions and nutrients

2 hormones produced by the adrenal medulla

Epinephrine (metabolic activities and bronchiole dilation) and norepinephrine (blood pressure)

Anterior pituitary ________ tissue

Glandular tissue

Cortisol (Released in response to ATCH, patterns of eating, and stress)

Gluconeogenesis- formation of glucose from fats and proteins Hyperglycemic

The chemical classification of hormones does not include

Glucose-containing hormones

Glucagon (targets liver, increases glucose)

Glycogenolysis and gluconeogenesis Hyperglycemic

GH (Decreases glucose uptake and metabolism)

Glycongenolysis- breakdown of glycogen to form glucose Hyperglycemic

The paraventricular nuclei and the supraoptic nuclei are located in the

Hypothalamus

Osmotic pressure of blood, ADH secretion, water reabsorption, hypothalamus

If ADH is secreted, it signals the kidney tubules to allow for reabsorption of water. So, water will come out of the kidney tubules making the urine more concentrated and the water will diffuse into the blood, increasing the osmotic pressure. The hypothalamus acts in a neuronal controlling mechanism over the Posterior Pituitary gland controlling the release of ADH from it.

Glucagon

In the alpha cells of the pancreas Amino acid Free in blood Needs plasma membrane receptor Targets the liver Breaks down glycogen to glucose Humeral Hypersecretion: Hyperglycemia Hyposecretion: More fat is stored in the liver

GSH

In the anterior pituitary Amino acid Free in blood Needs a plasma membrane receptor Effects muscles and bones Aids in bone growth Hormonal Hypersecretion: Gigantism Hyposecretion: Dwarfism

Thyroid Stimulating Hormone

In the anterior pituitary Amino acid Free in blood needs Plasma membrane receptor Targets the thyroid Stimulates the thyroid to secrete T3 and T4 Hormonal Hyposecretion: Cretinism in children, Myxedema in adults Hypersecretion: Effects similar to those of graves disease

Calcitonin

In the parafollicular C cells of the thyroid Amino acid Free in blood needs Plasma membrane receptor Targets bone cells Reduces the blood calcitonin levels Humeral

Neural hormones oxytocin and ADH are stored _______

In the posterior pituitary

Thyroid

In the thyroid Lipid based (steroid) Needs a carrier in the blood Needs a nuclear receptor Targets all body cells Aids in development Hormonal Hypersecretion: Above average levels for all body systems (Insomnia, BMR above normal) Hyposecretion: Lower levels of all body systems (Sluggish muscles, decreased heart pumping action)

Permissiveness

One hormone cannot exert its effects without another hormone being present

Antagonism

One or more hormones opposes action of another hormone

Sentence with: Hyperglycemia, beta cells, insulin, insulin receptors, target cell responsiveness to insulin, Type II diabetes mellitus

Insulin in secreted by beta cells in the pancreas. Type II diabetes is another term for having hyperglycemia. Because of their life style, they have desensitized their insulin receptors in their body meaning the responsiveness to insulin is decreased.

Difference between glucagon and insulin

Insulin responds to rising blood sugar levels Glucagon responds to dropping blood sugar levels

PIP2 - calcium signaling mechanism

Involves G protein and membrane bound effector (phospholipase C) The Phospholipase C splits PIP2 into 2 second messengers (DAG and IP3)

Insulin (lowers blood glucose)

It inhibits glycogenolysis and gluconeogenesis Hypoglycemic

Which is not a major endocrine organ, but produces hormones in addition to its major functions

Kidneys

Which endocrine glands are directly and indirectly controlled by the hypothalamus? What hormones are secreted by the hypothalamus? What are the targets for these hormones? Is hypothalamic control over these glands neural or hormonal in each case?

Liver, Thyroid gland, adrenal gland, mammary gland, ovary and testes, Kidneys GH, Thyroid stimulating hormone, ACTH, Prolactin, Luteinizing hormone, FSH, ADH, Oxytocin ADH and Oxytocin are Neural, others are hormonal

Paracrine

Locally acting chemicals that affect cells other than those that secrete them

Hormones

Long distance chemical signals (travel in blood or lymph)

Hormonal

Many endocrine glands release their horns in response to hormones produced by other endocrine glands

Synergism

More than one hormone produces same effects on target cell amplification

Neural

Nerve fibers stimulate hormone release

Posterior pituitary _____ tissue

Neural tissue

Lipid based are bound to what___

Plasma proteins

Dopamine

The inhibitory hormone responsible for regulation of prolactin (prolactin inhibiting hormone)

The metabolic rate of most body tissues is controlled directly by TH

The transcription of new messenger RNA is a function of steroid hormones

How do protein kinases affect enzymes

They add a phosphate group to then enzyme

What are the islets of langerhans and where would you find them

They are groups of pancreatic cells secreting insulin and glucagon (located in the pancreas)

Half-life

Time required for hormone's blood level to decrease by half

Target cells

Tissues with receptors for specific hormone

The hypothalamus is a

neuroendocrine gland

Endocrine glands

no ducts and secrete HORMONES into capillary beds

Decrease in blood calcium levels can be fixed with

parathyroid hormone

Decrease in body metabolism can be fixed with

thyroxine