Module 2

Front 1

Define Endocrine glands

and explain the difference between endocrine and paracrine

Back 1

1) They are organs that make hormones which travel through the bloodstream to reach their target tissues in other parts of the body

2) Organs are capable of creating their own chemical messengers (paracrine) or create messengers that travel to other parts of the body (endocrine)

* Only those organs that are primarily responsible for producing hormones are considered traditional endocrine organs

Front 2

The following are the endocrine glands:

1) Hypothalamus:

2) Pituitary glands:

3) Pineal gland:

4) Thyroid gland:

5) Parathyroid gland:

6) Adrenal gland:

7) Pancreas

8) Gonands:

Back 2

1) Brain control centre

2) also part of the brain, 2nd level of command

3) responsible for light and dark cycles

4) effects metabolism and calcium regulation

5) calcium regulation

6) involved in stress response, electrolyte regulation, sex hormones

7) energy sources

8) sex hormones

Front 3

Contrast the endocrine and nervous system

Back 3

Nervous system: quicker, targeted, neural connections

Endocrine system: slower, not targeted, all cells in the body are exposed only cells with receptors will respond

Front 4

Describe what are neurohormones

Back 4

are endocrine cells that are specialized neurons that secrete their contents directly into blood stream as oppose to a synapse

Front 5

Peptide hormones have the ability to come in many forms.

Define prohormone and prehormone

Give an example

Back 5

Prohormone: a precursor before the active hormone

Prehormone: a precursor before the prohormone

Preproinsulin - proinsulin - insulin

Front 6

Define:

1) synergistic effect

2) permissive effect

3) anatagonistic

Back 6

1) hormone works with other hormones to produce an effect in the same cell

2) work to enhance the responsiveness to another hormone

3) works to oppose another hormone

Front 7

What is the half life of a hormone

Back 7

the duration of action of a hormone. It is the time it takes for the blood level to be reduced by half. It allows for fine tuning of the response via negative feedback.

Front 8

What influences how a cell will respond to a hormone?

what causes side effects

Back 8

1) the enzyme may be stimulated or inhibited through the action of the hormone

2) the length of time the hormone is present in the blood

3) the concentration of hormone in the blood will determine how many receptors will be bound

Side effects are created pharmacologically when high concentrations of the hormone is present in the blood and they bind to receptors that normally similar chemicals

Front 9

* The presence of a hormone may affect a cell through other ways than simply binding receptors

Define what is priming (upregulation) and desensitization (downregulation)

Desensitization has caused hormones to be released in a ______ fashion

Back 9

1) the presence of a hormone will result in the production of more receptors for that hormone

2) some cells will remove receptors for a hormone if that hormone has been present for a long time at a high concentration

3) pulsatile

Front 10

1) Hormones can fall into what 3 categories ?

Back 10

1) steroids, monoamines, peptides

Front 11

Steroids:

1) they are derived from?

2) this makes them capable of doing and makes there receptors located

3) Examples of such are?

Back 11

1) cholesterol

2) they can move through the cell membrane, their receptors are inside the cell cytoplasm or nucleus

3) estosterone, estrogen, progesterone, aldosterone, cortisol, testosterone

Front 12

Monoamine hormones:

1) are derived from ?

2) there receptors are capable binding in two places? Where? Name examples of such.

Back 12

1) their amine groups (NH and NH2)

2) some of these hormone can bind within the cytoplasm (thyroxine) and other bind on the cell membrane (epinephrine and norepinephrine)

* dopamine

Front 13

Peptide hormones:

1) are chains of?

2) they are defined as not being ____ so they cannot pass through the _____

3) Name some examples of such. (8)

4) where do they bind

Back 13

1) amino acids

2) lipid soluble, cell membrane (receptors are located on the cell membrane)

3) ADH, GH, insulin, oxytocin, glucagon, adrenocorticotropic (ACTH), parathyrioid (PTH), angiotensin 2

4) Bind on the cell membrane

Front 14

Explain how steroid hormones behave similarly and differently.

Back 14

They both move through the cell membrane and bind to receptors in the cytoplasm. The receptor complex then moves through the nuclear membrane to bind DNA.

Steroids

- 2 hormone receptor complexes come together (Dimerize) and bind to DNA

Thyroid hormone

- a receptor hormone complex binds to a 9-cis-retinoic acid (vitamin a), a heterodimer then binds to DNA.

Front 15

Hydrophilic (water loving) hormones are not able to pass the cell surface.

- they use what type of pathways to alter behaviour

- name the pathways

Back 15

1) 2nd messengers

2) cAMP and phospholipase c-calcium pathway

Front 16

Describe the steps of the adenylate cyclase (cCAMP) pathway

Back 16

1) hormone - receptor binding activates a G-protein

2) G protein activates adenylate cyclase

3) adenylate cyclase produces cAMP

4) cAMP activates protein kinases

5) Protein kinases phosphorylae enzymes. This activates some enzymes and deactivates others

6) activated enzymes catalyze metabolic reactions with a wide range of possible effects on the cell

Front 17

Describe the phospholipase C-Ca pathway

Back 17

1. Hormone-receptor complex releases G protein, which activates phospholipase C

2. Phospholipase C splits a membrane phospholipid into 2nd messengers IP3 and DAG

3. IP3 diffuses through the cytoplasm to ER causing calcium channels to open

4. calcium diffuses into cytoplasm and binds to and activates calmodulin

5. calcium and calmodulin activates protein kinases which phosphorylates enzymes that produce hormone's effects

Front 18

Tyrosine Kinase 2nd messenger system is used by what hormone?

Explain how it works

Back 18

1) insulin and growth factors

2) insulin binds to a tyrosine kinase which consists of 2 units that form an active dimer this then leads to phosphorylation can glucose uptake

Front 19

Epinephrine can act via 2 messenger pathways. Name them.

Back 19

Adenylate cyclase pathway - beta-adrenergic receptors

Phospholipase C-Ca pathway - adrenergic receptors

Front 20

Insulin can also cause glucose uptake by what?

Back 20

Creating GLUT 4 carrier protein. 2nd messenger cause vesicles containing GLUT 4 transporters to be inserted into the membrane

Front 21

Describe the anterior pituitary and the posterior pituitary in relation to the hypothalamus.

Back 21

The anetrior pituitary receives blood w/ a high concentration of hypothalmic hormones via a portal system. The anterior pituitary releases hormone in response.

The posterior pituitary is connected to the hypothalmus by a stalk consisting of the axons of neurons whos cell bodies are located in the hypothalamus. The hormones that are released here travel down from the hypothalamus. (ADH, Oxytocin)

Front 22

Name the hypothalamic hormones.

Back 22

- Gonotropin releasing hormone

- Thyrotropin releasing hormone

- corticotropin releasing hormone

- prolactin inhibiting hormone

- growth hormone releasing hormone

- somatostatin

Front 23

Name the anterior lobe hormones

Back 23

- Follicle-stimulating hormone

- Luteinizing hormone

- Thyroid stimulatng hormone

- Adrenocorticotropic hormone

- Prolactin

- Growth Hormone

Front 24

1) The adrenal gland is divided into what 2 parts.

Back 24

1) The medulla which secretes epinephrine and norepinephrine.

2) The cortex is stimulated by ATCH from the pituitary and the 3 sections of the cortex secrete different hormones.

Zona glomerulus - mineralcorticoids

Zona fasciculate - glucocorticoids

Zona reticularis - sex hormones

Front 25

The medulla and the cortex are both involved in the stress response, how?

Back 25

The medulla secrete epinephrine which increase blood flow and the cortex secretes cortisol which increases blood glucose/protein levels

Front 26

What are the adverse effects of long term stress response.

Back 26

- atrophy of hippocampus (memory)

- reduced sensitivity to insulin (insulin resistance)

- inhibition of the vagus nerve (stomach upset/cardiac problems)

- suppression of growth hormone, thyroid hormone, gonadtropins

Front 27

The thyroid gland secrets what hormones?

The are responsible for doing what?

Explain the significance of idoine with thyroid hormone release.

Back 27

T3 and T4

Maintaining the basal metabolic rate and growth/development

Thyroid follicles take up iodine which form T3 and T4. When TSH from the pituitary is released it causes the hydrolysis of T4 and T3 glycoprotein complexes. The can now move into the bloodstream.

*T3 and T4 are kept inside the follicle because they are bound to a glycoprotein

Front 28

Thyroid hormonal axis is an example of ?

Back 28

1) negative feedback. Increases in T3 and T4 causes the decrease of production of TRH and TSH.

Front 29

Explain the role to thyroid gland plays with blood calcium

Explain the role the parathyroid gland plays with blood calcium

Back 29

1) C-cells produce a hormone called calcitonin which causes calcium to taken out of the blood and deposited in the bones.

2) They produce parathyroid hormone which increases blood calcium levels by increasing absorption from the GI tract or the bones.

Front 30

What does high blood calcium cause?

Low blood calcium leads to?

Back 30

1) Heart arrhythmias, muscle twitches, soft tissue calcification, kidney failure, and death

2) muscles cannot contract

Front 31

Describe the negative feedback loop of when there is high blood calcium.

Back 31

The thyroid releases calcitonin which reduced osteoclast activity (less bone resoprtion) and increases osteoblast activity. (more bone deposition)

Front 32

Describe the negative feedback loop of when there is low blood calcium

Back 32

Parathyroid hormone increases osteoclast activity and decreases osteoblast activity.

There is more urinary phosphate excretion (prevent hydroxyapatite) and less calcium excretion

Front 33

The endocrine cells are scatter throughout the pancreas in little aggregations called?

Back 33

Islets of Langerhans

Front 34

Describe how Beta-cells work.

Describe how Alpha-cells work

Back 34

1) B-cells secrete insulin in the response to high blood sugar. Insulin promotes the entry of glucose into cells and coverts in to glycogen (glycogenesis)

2) Alpha cells secrete glucagon in response to low blood glucose. Glucagon stimulates glycogenesis (breakdown of glycogen to glucose) and lipolysis (breakdown of triglycerides to free fatty acids) Glycogenolysis

Front 35

Explain how the pineal gland works in response to melatonin.

Back 35

It secretes melatonin in repsonse to suprachiasmatic nucleus of the hypothalamus. Melatonin is responsible for creating sleep schedules.

* Melatonin is responsible for sleep schedules

Front 36

What hormones does the placenta secrete?

Back 36

It secretes human chorionic gonadtropin (hCG) and somatomammotropin (development of mammary glands)

Front 37

Discuss the difference between autocrine and paracrine regulators.

Back 37

1) autocine are chemicals that are produced and act within the same tissue

2) paracrine are chemicals that are produced in one tissue and act on a different tissue in the same organ

Front 38

Prostaglandins are a group of ?

They are derived from?

Back 38

1) autocrine regulators

2) arachidonic acid

Front 39

Explain how COX1 and COX2 are involved in Prostaglandin synthesis.

Back 39

COX1 and COX2 are involved in prostaglandin synthesis. Non-steroidal inflammatory drugs target these. The problem is when COX1 is inhibited it leads to stomach ulcers because the prostaglandins that secrete protective stomach secretions are inhibited.

* Aspirin and Ibuprofen

Front 40

They are drugs that work on COX 2 only but they lead to cardiac problems. Name them.

Back 40

1) Celebrex and Vioxx

Front 41

Glucocorticoid hormones are steroid hormones that influence nutrient metabolism. These hormones activate genes for proteins involved in processes such as the synthesis of glucose, the breakdown of proteins, and the mobilization of fat. Glucocorticoid hormones are secreted by endocrine glands into the blood stream. They enter cells through transporters in the plasma membrane.Once inside the cytosol,the hormone molecules can bind to glucocorticoid receptors, which function as transcription factors that activate genes The binding of the hormones causes proteins that were bound to the receptors such as the heat shock protein HSP to be released. Release of HSP 90 allows two receptors to bind and form a dimer as well as exposing a nuclear localization signal on the receptor The receptor dimer is then allowed to enter into the nucleus through a nuclear pore. The receptor dimer is able to bind to specific DNA sequence regions called glucocorticoid response elements or GREs that are near target genes.The GREs function as enhancers,so that binding of a receptor dimer to a GRE activates transcription of the nearby target gene

Back 41

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Front 42

Thyroxin is a water insoluble hormone that is brought to the target cell via a protein carrier Because it is lipophilic, thyroxin can easily pass through the cell membrane.Thyroxin contains four iodines,and is often abbreviated T4, tetraiodothyronine.The thyroid gland also secretes smaller amounts of a similar molecule that has only three iodines,called triiodothyronine, T3.Both hormones enter target cells,1 but all the T4 that enters is converted into T3.Thus, only the T3 formof the hormone enters the nucleus,and binds to nuclear receptor proteins.The hormone receptor protein complex, in turn,binds to the appropriate hormone response elements on DNA.The binding of the hormone receptor complex has adirect effect on the level of transcription at the site where it binds.The messenger RNA, MRNA, produced then codes for specific proteins

Back 42

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Front 43

Steroid hormones are not water soluble. They travel in the blood, attached to protein carriers.When steroid hormones arriveat their target cells,they dissociate from their protein carriers, and pass through the plasma membrane of the cell.Some steroid hormones bind to specific receptor proteins in the cytoplasm, and then move as a hormone receptor complex into the nucleus.Other steroids travel directly into the nucleus before encountering their receptor proteins, not shown.The hormone receptor protein activated by binding to the hormone is now able to bindto specific regions of the DNA.These DNA regions are knownas the hormone response elements.The binding of the hormone receptor complex has a direct effect on the level of transcription at that site.Messenger RNA, MRNA, is produced,which then codes for the synthesisof specific proteins

Back 43

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