Endocrine System- Cell-to-Cell Signaling and Hormone Regulation

What is GH and what does it do?

(growth hormone) stimulates mitosis and cellular differentiation produced by The pituitary gland

HPA tract system steps

1. ADH and oxytocin are produced in nerve cell bodies in the hypothalamus 2.ADH and oxytocin move down axons (in the infundibulum) into the posterior pituitary (an extension of the hypothalamus) for storage 3. ADH and oxytocin are released into the bloodstream from the posterior pituitary 4. ADH acts on kidney tubules, oxytocin acts on the uterus and mammary glands

What is a hormone/signaling molecule?

A molecule produced and secreted by the body for signaling.

posterior pituitary hormones

ADH and OT

anterior pituitary gland

AKA the adenohypophysis, the anterior pituitary is made of glandular tissue. It makes and secretes six different hormones: FSH, LH, ACTH, TSH, prolactin, and growth hormone. The anterior pituitary is controlled by releasing and inhibiting factors from the hypothalamus

What happens if hypothalamus has a problem producing ADH?

Abnormal levels of ADH can occur.

What is the resulting effect on the target tissue for hydrophilic hormones?

Activation of second messenger systems.

What is ACTH and what does it do?

Adrenocorticotropic hormone - stimulate adrenal cortex to secrete corticosteroids produced by pituitary gland

Gene Expression

Altered by hydrophobic hormone activation, leads to protein synthesis

What is ADH and what does it do?

Antidiuretic hormone produced by the hypothalamus. Increases water reabsorption in kidney tubules.

What is ADH?

Antidiuretic hormone that regulates water balance.

Intercellular

Between cells

How do hydrophilic hormones act on target cell receptors?

Bind to cell surface receptors.

HPA Portal System

Blood vessels connecting hypothalamus and anterior pituitary gland

What is the target tissue(s) of the parathyroid?

Bones, kidneys, and intestines

How are hydrophobic hormones transported in the blood?

Bound to carrier proteins.

What is the target tissue(s) of the pineal body?

Brain and other tissues

Paracrine Signaling

Cell secretes signaling molecules that act on nearby cells

Endocrine

Cell signaling through the bloodstream

Paracrine

Cell signaling to nearby cells

Direct Contact

Cells in direct physical contact with each other

Gap Junctions

Channels between cells allowing rapid spread of electrical signals

Hormone

Chemical messenger produced by glands

What are hydrophilic hormones composed of?

Composed of amino acids or peptides.

What are hydrophobic hormones composed of?

Composed of lipids or steroids.

What is diabetes insipidus?

Condition caused by insufficient ADH production.

Hypothalamohypophyseal axis

Connection between the hypothalamus and pituitary gland

How is the adrenal cortex controlled and when is it released?

Controlled by ACTH, released in response to stress

How is the thyroid controlled and when is it released?

Controlled by TSH, released as needed

How is the parathyroid controlled and when is it released?

Controlled by blood calcium levels, released when calcium is low

How is the pancreas controlled and when is it released?

Controlled by blood glucose levels, released when glucose is high

How are the ovaries controlled and when are they released?

Controlled by hormones, released during menstrual cycle

How are the testes controlled and when are they released?

Controlled by hormones, released during puberty

How is the thymus controlled and when is it released?

Controlled by hormones, released throughout life

How is the pineal body controlled and when is it released?

Controlled by light and dark cycles, released at night

How is the adrenal medulla controlled and when is it released?

Controlled by sympathetic nervous system, released during fight or flight response

Hypothalamus

Controls release of hormones from the pituitary gland

What is CRH and what does it do?

Corticotropin-releasing hormone produced by the hypothalamus

Thyroid Disorders

Cretinism(Congenital Hypothyroidism)- Hyposecretion of thyroid hormones due to lack of development of thyroid gland. Hypothyroidism Hyperthyroidism Thyroiditis Goiter- Hyposecretion of T3/T4 which causes the thyroid to grow larger to make up for the lack of hormones Thyroid cancer Gigantism Pituitary Dwarfism (sometimes called proportionate dwarfism)

How does abnormal ADH levels affect blood pressure?

Decreased blood pressure (hypotension).

How does abnormal ADH levels affect blood volume?

Decreased blood volume (hypovolemia).

How does abnormal ADH levels affect the kidneys?

Decreased water reabsorption in the kidneys.

How do hydrophobic hormones act on target cell receptors?

Diffuse across the cell membrane and bind to intracellular receptors.

Gap junction

Direct cell-to-cell communication channel

What is the resulting effect on the target tissue for hydrophobic hormones?

Directly alter gene expression.

How are hydrophilic hormones transported in the blood?

Dissolved in the plasma.

Cushing's disease

Elevated cortisol

How and where does the body store excess glucose?

Excess glucose is stored as glycogen in the liver and muscles.

What is FSH?

Follicle Stimulating Hormone.

What is FSH and what does it do?

Follicle-stimulating hormone Released by the pituitary gland Causes a follicle (an egg and its surrounding cells) to mature in one of the ovaries Stimulates oestrogen production produced by the Anterior pituitary gland

Nervous system and endocrine system both

Function both as hormones and neurotransmitters (norepinephrine, epinephrine, dopamine) Can trigger/ regulate each other. Can have overlapping effects (conversion of glycogen into glucose in the liver)

anterior pituitary hormones

GH, TSH, ACTH, FSH, LH, PRL, MSH

At what point in a typical day are glucagon levels likely to increase in the body?

Glucagon levels increase during periods of fasting or prolonged exercise when blood glucose levels are low.

How does the body respond to glucagon?

Glucagon stimulates the breakdown of glycogen into glucose and the release of glucose into the bloodstream.

What is GnRH and what does it do?

Gonadotropin Releasing Hormone: increases FSH( follicle-stimulating hormone) and LH( luteinizing hormone) produced by the hypothalamus.

What is GH?

Growth Hormone - also called somatotropin.

What is GHRH and what does it do?

Growth Hormone Releasing Hormone: increases Growth Hormone ( GH) hypothalamus. produced by the Anterior pituitary gland

What causes the release of insulin?

High blood glucose levels stimulate the release of insulin.

Cortisol

Hormone released by adrenal cortex to help the body cope with stress

Insulin

Hormone released by pancreas in response to high blood glucose levels

Glucagon

Hormone released by pancreas in response to low blood glucose levels

Insulin

Hormone released by pancreas to regulate blood glucose levels

Oxytocin

Hormone released by posterior pituitary, stimulates uterine contractions and milk ejection

HPA

Hypothalamo-hypophyseal tract

What is the target tissue(s) of the thymus?

Immune system

What happens to urine output in diabetes insipidus?

Increased urine output (polyuria).

What is the function of PRL in males?

Increases LH sensitivity, thus increasing testosterone secretion.

Intracellular

Inside the cell

At what point in a typical day are insulin levels likely to increase in the body?

Insulin levels increase after a meal, especially when carbohydrates are consumed.

What is the relationship between insulin, glucagon, glycogen, and glucose?

Insulin lowers blood glucose levels, while glucagon raises them. Glycogen is the stored form of glucose.

How does the body respond to insulin?

Insulin promotes the uptake of glucose by cells and the storage of excess glucose as glycogen.

Hydrophobic Hormones

Lipid-soluble hormones that can pass through the cell membrane

What is the target tissue(s) of the pancreas?

Liver, muscle, and adipose tissue

Intracellular Receptors

Located inside the cell, bind to hydrophobic hormones

Membrane-Bound Receptors

Located on the cell membrane, bind to hydrophilic hormones

What causes the release of glucagon?

Low blood glucose levels and certain hormones stimulate the release of glucagon.

What is LH?

Luteinizing Hormone.

What is LH?

Luteinizing hormone produced by the pituitary gland.

Glucose

Main source of energy for cells, regulated by insulin and glucagon

Second messenger

Molecule that relays signals inside the cell

Synaptic Signaling

Neuron releases neurotransmitters that act on adjacent neurons

Acetylcholine

Neurotransmitter released at neuromuscular junction to stimulate muscle contraction

Gland

Organ that produces and releases substances

Extracellular

Outside the cell

oxytocin role in hypothalamus

Oxytocin is involved in facilitating childbirth and lactation, and is also thought to influence sexual and social behavior in males and females

What is OT?

Oxytocin produced by the hypothalamus.

Protein synthesis

Process of building proteins in cells

Ovaries

Produce estrogen and progesterone, regulate female reproductive functions

Adrenal Glands

Produce hormones such as cortisol and aldosterone, involved in stress response and electrolyte balance

Testes

Produce testosterone, regulate male reproductive functions

What is the function of the thymus?

Produces T-cells for immune system

What is the function of the adrenal medulla?

Produces adrenaline and noradrenaline for stress response

What is the role of hypothalamus in ADH production?

Produces and releases ADH into the bloodstream.

Anterior Pituitary

Produces and releases hormones such as growth hormone and thyroid-stimulating hormone

Pituitary Gland

Produces and releases hormones, controlled by hypothalamus

What is the function of the adrenal cortex?

Produces cortisol and aldosterone for stress response

What is the function of the ovaries?

Produces estrogen and progesterone for reproductive system

Pancreas

Produces insulin and glucagon to regulate blood glucose levels

What is the function of the pancreas?

Produces insulin and glucagon to regulate blood sugar levels

What is the function of the pineal body?

Produces melatonin to regulate sleep-wake cycles

Pineal Body

Produces melatonin, regulates sleep-wake cycles

What is the function of the parathyroid?

Produces parathyroid hormone to regulate calcium levels

Parathyroid

Produces parathyroid hormone, regulates calcium levels in the blood

What is the function of the testes?

Produces testosterone for reproductive system

Thymus

Produces thymosin, involved in the development of T cells in the immune system

Thyroid

Produces thyroid hormones that regulate metabolism and growth

What is the function of the thyroid?

Produces thyroid hormones to regulate metabolism

What is Prl?

Prolactin produced by the pituitary gland.

What is PrlIH?

Prolactin-inhibiting hormone produced by the hypothalamus.

What is PrlRH?

Prolactin-releasing hormone produced by the hypothalamus.

What is PRL?

Prolactin.

What is the function of PRL in females?

Promotes milk production after delivery.

Gonadotropin-releasing hormone (GnRH)

Promotes secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH)

What is the function of GH?

Promotes tissue growth, especially muscles and bones.

HPA Tract System

Regulates body's response to stress, involves hypothalamus, pituitary gland, and adrenal cortex

What is the function of ACTH?

Regulates response to stress, stimulates adrenal gland cortex to secrete corticosteroids that regulate glucose, fat and protein metabolism.

What is the function of TSH?

Regulates response to stress, stimulates adrenal gland cortex to secrete corticosteroids that regulate glucose, fat and protein metabolism.

What is the target tissue(s) of the ovaries?

Reproductive system

What is the target tissue(s) of the testes?

Reproductive system

Histamine

Signaling molecule released by mast cells to recruit immune cells

Endocrine Signaling

Signaling molecules released into bloodstream and act on distant target cells

Difference between Nervous System and Endocrine System (Name 2)

Speed and Length of Response: Nervous System: reacts quickly and stops quickly. Endocrine System: reacts slowly and can take days to weeks for hormones to release Ie: ovulation. Size Of Area Affected Nervous System: Effects one specific target or area Endocrine System: are more widespread i.e. testosterone (facial growth, bigger muscle mass. "Body wide effects"

What is the function of ovaries?

Stimulates development of eggs and follicles.

What is the function of LH?

Stimulates growth of thyroid gland and secretion of thyroid hormones (T3 and T4).

What is the function of FSH in males?

Stimulates interstitial cells of testes to secrete testosterone.

What is the function of FSH in females?

Stimulates ovulation and secretion of progesterone and estrogen.

What is the function of testes?

Stimulates production of sperm.

Glycogen

Stored form of glucose in the liver and muscles

Posterior Pituitary

Stores and releases hormones produced by the hypothalamus

What is the HPA portal system?

The HPA portal system is a specialized network of blood vessels that carries blood from the hypothalamus to the anterior pituitary gland.

What is the HPA tract system?

The HPA tract system is a network of blood vessels that transports oxygen and nutrients to the body's tissues.

What is TSH?

Thyroid Stimulating Hormone.

What is TSH and its function?

Thyroid-stimulating hormone produced by the pituitary gland. Thyroid hormones regulate the metabolism of almost every tissue in the body

What is TRH?

Thyrotropin-releasing hormone produced by the hypothalamus.

Signal Transduction Pathways

Triggered by hydrophilic hormone activation, leads to cellular response

Monoamine

Type of hormone derived from amino acids

Steroid

Type of hormone derived from cholesterol

Nervous System

Uses electrical signals to transmit information, fast and specific

Endocrine System

Uses hormones to transmit information, slower and more widespread

Endocrine Disorders

Various endocrine glands affected, resulting in hormone imbalances

What is the target tissue(s) of the thyroid?

Various tissues in the body

Hydrophilic Hormones

Water-soluble hormones that bind to membrane-bound receptors

What is ACTH?

adrenocorticotropic hormone (corticotropin) adrenocorticotropic hormone; target = adrenal cortex; adrenal cortex releases glucocorticoids

posterior pituitary gland

also known as the neurohypophysis; it is made up of nervous tissue/neurons and stores and secretes 2 hormones made by the hypothalamus (oxytocin and ADH); it is controlled by action potentials from the hypothalamus

Graves disease

an autoimmune disorder that is caused by hyperthyroidism and is characterized by goiter and/or exophthalmos

diabetes insipidus (DI)

condition caused by insufficient antidiuretic hormone secreted by posterior lobe of pituitary gland; symptoms include polyuria and polydipsia

Goiter

enlargement of the thyroid gland caused by thyroid dysfunction, tumor, lack of iodine in the diet, or inflammation

gigantism

excessive growth of body due to hypersecretion of growth hormone in a child or teenager

What is GHIH and what does it do?

growth hormone inhibiting hormone (somatostatin), inhibits release of GH and TSH produced by The pituitary gland

tropic hormones

hormones that stimulate other glands to release their hormones

What kind of tract does the Posterior pituitary use?

hypothalamo-hypophyseal tract

main endocrine glands

hypothalamus, pituitary, thyroid, parathyroid, adrenals, pancreas, ovaries, testes

Hypothalamo-Pituitary-Adrenal Axis

link between the hypothalamus, pituitary gland, and the adrenal cortex a coordinated physiological response to stress involving the hypothalamus of the brain and the pituitary and adrenal glands

hypothalamo-hypophyseal tract

neural connection between the hypothalamus and the posterior pituitary