Lectures 1 & 2 - Endocrine System

What hormone does the liver produce?

Angiotensin

What hormone does the thymus produce?

Thymosin (promotes T-cell development)

What hormone does the heart produce?

BNP (Brain natriuretic peptide)

What hormones does the kidney produce?

Renin and erythropoetin

What hormone dos the stomach produce?

Gastrin

What hormones does the duodenum produce?

Secretin and CCK (Cholecystokinin)

What hormone does the skin produce?

Some species make vitamin D3 in their skin, which has the properties of a hormone

What hormone does the placenta produce?

Relaxin

What type of hormone needs a carrier to travel through the blood? (ex. hydrophilic or hydrophobic/lipophilic)

Hydrophobic/ Lipophilic

What type of hormone attaches to receptors on the cell surface? (ex. hydrophilic or hydrophobic/lipophilic)

Hydrophilic

What type of hormone attached to receptors in the cytoplasm or nucleus? (ex. hydrophilic or hydrophobic/lipophilic)

Hydrophobic/ Lipophilic

What type of hormone travels freely through the blood? (ex. hydrophilic or hydrophobic/lipophilic)

Hydrophilic

Is a steroid hormone hydrophilic or hydrophobic?

Hydrophobic/ Lipophilic

Is an amine hormone hydrophilic or hydrophobic?

Hydrophilic

Is a peptide hormone hydrophilic or hydrophobic?

Hydrophilic

Is a protein hormone hydrophilic or hydrophobic?

Hydrophilic

What are the different types of intercellular communication?

- Endocrine;

- Paracrine;

- Autocrine;

- Synaptic;

- Neuroendocrine

What is endocrine signalling?

Hormones are released into the bloodstream and travel to distant target cells

What is paracrine signalling

Hormones or signalling molecules act on nearby cells without entering the bloodstream

What is autocrine signalling?

A cell releases signals that act on itself to regulate its own activity

What is synaptic signalling?

Neurotransmitters are released across a synapse to communicate with a neighbouring neuron or target cell

What is neuroendocrine signalling?

Nerve signal stimulates hormone release

How are hydrophilic hormones broken down?

They are broken down by the liver or filtered out by the kidneys

How are hydrophobic/lipophilic hormones broken down?

They last longer in the blood than hydrophilic hormones. Some free hormones dissolve in the plasma. They are then broken down by the liver or filtered out by the kidneys

What hormones does the hypothalamus create and release?

- GnRH (Gonadotropin releasing hormone);

- CRH (Corticotropin releasing hormone);

- TRH (Thyrotropin releasing hormone);

- GHRH (Growth hormone releasing hormone);

- PRH (Prolactin releasing hormone);

- Oxytocin;

- ADH (Antidiuretic hormone)

What hormones does the posterior pituitary create and release?

None - the posterior pituitary only stores and releases hormones created by the hypothalamus

What hormones does the posterior pituitary store and release?

Oxytocin and ADH (antidiuretic hormone)

What organ does oxytocin act on?

Mammary glands and uterus

What does ADH (antidiuretic hormone) do?

Acts on the kidney to stimulate water reabsorption

What hormones does the anterior pituitary produce and release?

- ACTH (Adrenocorticotropic hormone);

- FSH (Follicle stimulating hormone);

- LH (Luteinizing hormone);

- TSH (Thyroid stimulating hormone);

- Prolactin;

- GH (Growth hormone)

What hypothalamic hormone stimulates the release of ACTH (Adrenocorticotropic hormone)?

CRH (Corticotropin releasing hormone)

What hypothalamic hormone stimulates the release of FSH (Follicle stimulating hormone) and LH (Luteinizing hormone)?

GnRH (Gonadotropin releasing hormone)

What hypothalamic hormone stimulates the release of TSH (Thyroid stimulating hormone)?

TRH (Thyrotropin releasing hormone)

What hypothalamic hormone stimulates the release of Prolactin?

PRH (Prolactin releasing hormone)

What hypothalamic hormone stimulates the release of GH (Growth hormone)?

GHRH (Growth hormone releasing hormone)

What organ does ACTH (Adrenocorticotropic hormone) act on?

Adrenal cortex

What organ does FSH (Follicle stimulating hormone) and LH (Luteinizing hormone) act on?

The gonads (testes and ovaries)

What organ does TSH (Thyroid stimulating hormone) act on?

Thyroid gland

What organ does Prolactin act on?

Mammary glands

What organ does GH (Growth hormone) act on?

Liver and all of body

What actions does GH (growth hormone) have on the body?

- Bone/muscle growth in young animals;

- Regulation of protein, carbs, and lipids in all cells;

- Anabolism of proteins;

- Catabolism of lipids in fat;

- Increases hepatic gluconeogenesis;

- Inhibits cells from using glucose

What disease is associated with too much GH (growth hormone)?

Acromegaly (anterior pituitary tumour)

What disease is associated with too little GH (growth hormone)?

Pituitary dwarfism

What is another name for growth hormone?

Somatotropin

What action does prolactin have?

Begins and maintains lactation

What type of feedback loop is associated with prolactin release?

Positive feedback loop

What action does oxytocin have on the mammary glands?

Milk let-down

What action does oxytocin have on the uterus?

Contraction of the uterus for parturition and fertilization

What is another name for TSH (thyroid stimulating hormone)?

Thyrotropic hormone

What action does TSH (thyroid stimulating hormone) have?

Acts on thyroid gland to produce and release T3 and T4

What type of feedback loop is associated with TSH (thyroid stimulating hormone) release?

Negative feedback loop

Where is the thyroid gland located?

On either side of the trachea

What hormones are produced and released by the thyroid gland in response to TSH (thyroid stimulating hormone)?

T3 and T4

Which of the two thyroid hormones (T3 or T4) is a pro-hormone that circulates freely in the blood?

T4

Which of the two thyroid hormones (T3 or T4) is the active form of the thyroid hormone?

T3

What are the effects of thyroid hormone?

- Increases the rate of calorie usage;

- Controls body temperature;

- Development of the CNS;

- Growth and development of muscles and bones;

- Anabolism (synthesis) of proteins;

- Increased gluconeogenesis

What disease is associated with an iodine deficiency?

Goiter

What disease is associated with too much thyroid hormone?

Hyperthyroidism

Which species (cats or dogs) is more prone to hyperthyroidism?

Older cats

What disease is associated with too little thyroid hormone?

Hypothyroidism

Which species (cats or dogs) is more prone to hypothyroidism?

Some dog breeds

How can goiter be treated?

Dietary iodine supplementation

How can hyperthyroidism be treated?

Surgery, medication, limited iodine diet, or radioactive iodine

How can hypothyroidism be treated?

Thyroid hormone supplementation

What hypothalamic hormone stimulates the release of calcitonin?

None! Calcitonin is released from C-cells in the thyroid gland and is under control of the C-cells directly

What effect does calcitonin have?

Decreases blood calcium levels (puts calcium into the bones)

What is another name for parathyroid hormone (PTH)?

Parathormone

What hypothalamic hormone stimulates the release of parathyroid hormone (PTH)?

None! Parathyroid hormone is released from the parathyroid gland in response to low blood calcium levels

What effect does parathyroid hormone (PTH) have?

Increases blood calcium levels (takes calcium out of the bones)

What are some diseases associated with too much parathyroid hormone (PTH)?

- Rubber jaw (secondary nutritional hyperparathyroidism);

- Secondary renal hyperparathyroidism;

- Primary hyperparathyroidism (parathyroid gland tumour)

What effect does FSH (follicle stimulating hormone) have in a female?

- Stimulate oogenesis;

- Superovulation;

- Cycle timing;

- Stimulates follicle lining to make estrogen

What effect does FSH (follicle stimulating hormone) have in a male?

Stimulates spermatogenesis in seminiferous tubules

What effect does luteinizing hormone (LH) have in a female?

Stimulates estrogen production in the follicle

What type of feedback loop is associated with estrogen?

Positive feedback loop (dec. FSH and inc. LH)

What effect does lutenizing hormone (LH) have on the male?

Stimulates interstitial cells in testes to make testosterone

What is another name for lutenizing hormone (LH) in the male system?

ICSH (Interstitial cell stimulating hormone)

What are the three types of hormones released by the ovaries?

Estrogens, progestins, and relaxin

What is the primary type of estrogen released by the ovary?

Estradiol

What effect does extradiol have?

Causes physical and behavioural chances to prepare for breeding and pregnancy

What is the primary type of progestin released by the ovary?

Progesterone

What part of the ovary releases progesterone?

Corpus luteum

What effect does progesterone have?

Maintains pregnancy

What part of the ovary makes relaxin?

Corpus luteum (or uterus or placenta in some species)

What effect does relaxin have?

Relaxes ligaments of birth canal for parturition

Which ovarian hormone can be used as a pregnancy test factor in dogs?

Relaxin

Where is testosterone made?

Interstitial cells

What hormone stimulates the production of testosterone?

FSH (Follicle stimulating hormone)

What effect does testosterone have on the body?

Development of accessory sex glands and growth of penis

Which hormones are produced by and released from the adrenal glands in response to ACTH (Adrenocorticotropic hormone) from the anterior pituitary?

Mineralocorticoids (ex. aldosterone), glucocorticoids, and androgens/estrogens (sex hormones)

What are two primary examples of glucocorticoids from the adrenal cortex?

Cortisol and cortisone

What effect do glucocorticoids have?

Increases blood glucose levels and long term stress

What disease is associated with too much glucocorticoid production?

Cushing's disease (hyperadrenocorticism)

What disease is associated with too little glucocorticoid production?

Addison's disease (Hypoadrenocorticism)

What is an example of a mineralocoriticoid released by the adrenal gland?

Aldosterone

What effect does aldosterone have on the body?

Increases blood pressure and volumte by acting on the kidneys

What hormones are produced and released by the adrenal medulla?

Epinephrine and norepinephrine

What type of stress is associated with epinephrine and norepinephrine?

Short term stress

What effect does ADH (antidiuretic hormone) have on the body?

Tells the kidneys to reabsorb more water

What is a disease associated with too much ADH (antidiuretic hormone)?

Diabetes insipidus

What hormone is released by the pinealo gland?

Melatonin