Sign In | Subscribe

Enter your Sign on user name and password.

Forgot password?
  • Follow us on:
Start learning today, and be successful in your academic & professional career. Start Today!
Loading video...
This is a quick preview of the lesson. For full access, please Log In or Sign up.
For more information, please see full course syllabus of Anatomy & Physiology
  • Discussion

  • Study Guides

  • Download Lecture Slides

  • Table of Contents

  • Transcription

  • Related Books

Lecture Comments (7)

1 answer

Last reply by: Bryan Cardella
Tue Mar 8, 2016 5:24 PM

Post by Clarissa Torres on March 8, 2016

How does Cyclic AMP signalling mechanism tie into the Endocrine System?

1 answer

Last reply by: Bryan Cardella
Thu Feb 18, 2016 2:11 PM

Post by karen mosquera on February 17, 2016

what are the properties of the hypothalamus and the pituitary gland?

0 answers

Post by Madina Abdullah on May 12, 2014

Really useful and good explanation, Thank you

1 answer

Last reply by: Bryan Cardella
Tue Feb 4, 2014 10:18 AM

Post by JASON YUEN on February 4, 2014


You are Good!

Endocrine System

  • Hormones are the chemical signal molecules for the body and they travel through the blood stream to stimulate (or turn off) physiological activities in target cells
  • Hormones are either amino acid derivatives, peptide hormones, or lipid derivatives
  • Negative feedback and positive feedback deal with how hormone release is regulated
  • The hypothalamus secretes regulatory hormones to control the pituitary gland and other endocrine glands
  • The anterior pituitary gland secretes prolactin (PRL), thyroid-stimulating hormone (TSH), gonadotropins (FSH and LH), and growth hormone (GH)
  • The pituitary gland secretes anti-diuretic hormone (ADH) and oxytocin
  • The thyroid gland secretes T3 and T4, which regulate metabolism
  • The parathyroid glands secrete parathyroid hormone (PTH) for calcium ion regulation
  • The adrenal glands are located on the superior end of the kidneys and they contain a cortex and medulla
  • The adrenal cortex secretes aldosterone, cortisol, and androgens
  • The adrenal medulla secretes epinephrine (adrenaline) and norepinephrine (noradrenaline)
  • The kidneys secrete calcitriol, erythropoietin (EPO), and renin
  • The pancreas secretes insulin, glucagon, and somatostatin for the regulation of blood sugar levels
  • The pineal gland secretes melatonin for circadian rhythm regulation (sleep cycle)
  • The thymus secretes thymosins to aid in T-cell maturation and development
  • Gonad hormones include: estrogen/progesterone in the ovaries and androgens in the testes
  • Endocrine conditions/disorder examples: Diabetes mellitus Type I and II, Diabetes insipidus, Addison disease, hyperthroidism, goiter, and pituitary gigantism
  • Did you know…
    • Q: I’ve read about norepinephrine as a neurotransmitter, but it’s listed as a hormone in this lesson. Which one is it?
    • A: Both, depending on where it is in the body. Neurotransmitters exist in the brain, spinal cord, and nerves. They are the signals that move across synapses for neuronal signaling. Hormones are the chemical messengers contained within the blood stream that affect target cells. The same molecule can be both a neurotransmitter and hormone.

Endocrine System

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

  • Intro 0:00
  • Hormone Basics 0:05
    • Hormones
    • Classes of Hormones
  • Negative vs. Positive Feedback 3:22
    • Negative Feedback
    • Positive Feedback
  • Hypothalamus 6:20
    • Secretes Regulatory Hormones
    • Produces ADH and Oxycotin
    • Controls Endocrine Action of Adrenal Glands
  • Anterior Pituitary Gland 8:27
    • Prolactin
    • Corticotropin
    • Thyroid-Stimulating Hormone
    • Gonadotropins
    • Growth Hormone
  • Posterior Pituitary Gland 12:29
    • Antidiuretic Hormone
    • Oxytocin
  • Thyroid Gland Anatomy 15:16
    • Two Lobes United by an Isthmus
    • Contains Follicles
  • Thyroid Gland Physiology 16:50
    • Thyroxine
    • Triiodothyroine
  • Parathyroid Anatomy / Physiology 18:52
    • Secrete Parathyroid Hormone (PTH)
  • Adrenal Gland Anatomy 20:09
    • Contains Cortex and Medulla
  • Adrenal Cortex Physiology 21:40
    • Aldosterone
    • Glucocorticoids
    • Androgens
  • Adrenal Medulla Physiology 23:53
    • Epinephrine
    • Norepinephrine
    • Fight or Flight
    • Contribute to…
  • Kidney Hormones 26:11
    • Calcitriol
    • Erythropoietin
    • Renin
  • Pancreas Anatomy 28:18
    • Exocrine Pancreas
    • Endocrine Pancreas
  • Pancreas Physiology 29:50
    • Glucagon
    • Insulin
    • Somatostatin
  • Pineal Gland Anatomy / Physiology 32:10
    • Contains Pinealocytes
    • Produces Melatonin
  • Thymus Anatomy / Physiology 34:17
    • Max Size Before Puberty
    • Secrete Thymosins
  • Gonad Hormones 35:45
    • Testes
    • Ovaries
  • Endocrine Conditions / Disorders 37:28
    • Diabetes Type I and II
    • Diabetes Type Insipidus
    • Hyper / Hypoglycemia
    • Addison Disease
    • Hyper / Hypothyroidism
    • Cretinism
    • Goiter
    • Pituitary Gigantism / Dwarfism
    • IDD Iodized Salt

Transcription: Endocrine System

Hi and welcome to

This is the lesson on the endocrine system.0002

We will talk about hormones with the endocrine system because those are little messengers that make the whole thing work.0004

The endocrine systems all about hormones, the glands they come from, and what tissues they are effecting.0011

The main function is to preserve homeostasis.0017

To keep balance in the body because depending on what your current condition0021

is physiologically something needs to be adjusted.0027

Stimuli changes in the environment, conditions change in your body was built to adjust quickly and hormones the way that happens.0029

With hormones it is all about endocrine communication and it is inside the body between tissues via the bloodstream.0038

There other communications inside the body like parocrine communication that tends to be more close quarters0047

like one tissue neighbor another tissue and stimulating that way.0055

But with endocrine communication you will have a signal sent from part of brain that goes all the way to the adrenal glands.0058

Which in terms of blood flow is quite a distance.0065

Endocrine communication is involving hormones in the bloodstream.0069

Each hormone has a target cell that is an important term.0074

For instance a very important target cell for insulin would be in the liver.0081

Insulin is like a key that helps getting sugar out of the bloodstream and package away in your liver.0087

Other hormones do not impact the liver because they have other target cells.0095

Some hormones their target cells might be just the stomach or might be just your muscles.0101

The target cell is going to have specific receptors meaning specific proteins that is, like a lock and key mechanism.0109

Think of the key as being a specific hormone and the locked corresponds to that hormone shape and structure.0118

In other cells do not have that particular lock so hormones just drift by them and not dock on them and affect them the same way.0125

Endocrine glands are the specific tissues or organs that actually produce hormones.0133

In terms of the structure of hormones what they are made from, there a 3 main classes of hormones.0141

Amino acid derivative, sense of amino acids in very specific sequences are going to give you thyroid hormone.0150

Hormones from the thyroid gland here.0157

Epinephrine also known as adrenaline is made from amino acids.0159

Dopamine which is not only a hormone but also considered a neurotransmitter in the brain that is made from amino acids.0164

Peptide hormones, thyroid stimulating hormone, luteinizing hormone and follicle stimulating hormones.0171

These two have to do with the gonads, the testes, your ovaries.0177

This one stimulates the thyroid gland so that it actually secretes and releases thyroid hormone.0181

There are lipids derivative, made from fat up.0188

Androgen and estrogens the sex hormones antigens associated with males and estrogen more associated with females.0191

Those without fat in the body often will not produce those.0197

Negative versus positive feedback.0201

With negative feedback that is the most common way that hormone release is regulated.0205

Basically what happens is it is kind of like a thermostat that is the analogy that I think is best for this.0212

Think about a thermostat, let us say you set the thermostat to 72 degrees or 20° C.0221

That thermostat is going to cause release of cold air up to a point so cold air is going to be released0228

and eventually the thermostat is going to shut off that cold air.0238

When is shut it off when you finally get to 72° F or 20° C.0243

On that is how lot of endocrine glands work.0248

For instance when you look at insulin release related to glucose levels.0251

Blood sugar rises when you eat something that high sugar and you need sugar in it.0255

Your pancreas is only going to keep releasing insulin until that blood glucose level drops like temperature dropping in a room.0259

Once the blood glucose level gets to an appropriate level, your brains going to notice that is going to send a signal to the insulin builder0270

and the pancreas saying now you can stop releasing it because we got to the level that we needed to get.0279

The negative feedback, that drop and whenever you are modifying or drop0286

and whenever you are acting on that is going to affect what initiated the process.0292

A buildup of the product or removal of something will eventually shut off what was initiating the builders of that buildup.0297

You could say it that way.0307

Remember the thermostat, it is very similar to how insulin get sugars out of the bloodstream.0308

Positive feedback not as common because of positive feedback it is a buildup of the product further stimulates it is like keep happening.0315

It just adds and adds to a point.0327

The product further enhances production.0331

One example is labor pains in relation to delivering a baby.0334

Hormones stimulating the uterine muscles to get the baby out gradually that is going to keep happening.0338

Labor early on not quite as intense as labor further along.0348

The piling on of platelets when you have cuts and laceration in a blood vessel,0354

the piling on of platelets they keep attracting more platelets until it is sealed.0362

That is positive feedback.0368

I have heard that orgasms have a lot to do with positive feedback.0369

Negative feedback that much more common in terms of regulating hormone levels.0374

The hypothalamus is like the head honcho.0380

They running the show in terms of regulating endocrine system and stimulating glands to do what they do.0384

You can think of the hypothalamus as the CEO and the president.0391

The pituitary gland which is found underneath it is the one that is doing it is bidding.0394

It is like the vice president or that the person that is actually sending along the signals from the head honcho.0400

This is a part of the brain it is the inferior portion of the diencephalon.0408

The diencephalon right in here inferior to the corpus callosum which is really deep in the brain but above the brain stem.0413

Right here 16 that is the hypothalamus.0422

Thalamus is up here.0431

From the hypothalamus you are going to have the pituitary gland hanging just below that.0433

The hypothalamus actually keeps tab of what is going on in the bloodstream and what the other endocrine glands are doing.0438

Then it will respond as needed.0446

It is actually making regulatory hormones that will tell certain endocrine glands either to release more or to hold off.0449

It controls the pituitary gland.0457

The pituitary gland secretes many different hormones which are going to come up in a little bit.0459

The hypothalamus produces ADH.0464

You are going to hear more about that in a bit, anti diuretic hormone and oxytocin but0466

they are released into the bloodstream through the pituitary gland that adjacent P shape little sac.0470

It controls endocrine connection of the adrenal glands as well as its automatic centers.0476

This corresponds to that sympathetic branch of the autonomic nervous system.0482

The hypothalamus keeps tabs on what your brain is noticing about, threats in the environment and what to do about them.0487

There is a lot of direct control of the release of epinephrine and norepinephrine which are adrenaline.0496

In terms of getting your body going for that fight or flight response.0503

We will move to the pituitary glands, this little pea sized hanging beneath the hypothalamus.0506

It is in the celatursica, this is a little computer animation of the two parts of the pituitary gland.0515

If you saw the skeletal lessons there is a well celatursica that means Turkish saddle in the sphenoid bone of the cranium.0522

That little well is where the pituitary gland is saddling up.0536

The pituitary gland has two sides.0540

The anterior pituitary towards the front and the posterior pituitary on the backside.0543

These hormones like I have said before are secreted to regulate other gland.0550

Some examples, the anterior pituitary, this orange side of it secrete prolactin.0554

Prolactin meaning production of milk in females when they are breastfeeding is thanks to prolactin being secreted.0563

The function for prolactin in males not fully understood but it is found in the male bloodstream.0573

Corticotropin has a lot to do with regulating adrenal glands which release adrenaline.0578

That comes from the anterior pituitary as well.0584

Thyroid stimulating hormone guess what that stimulates, the thyroid gland.0587

Gonadotropins include the two kinds of hormones that are going to impact the ovaries or testes.0591

Whichever pair you have if you are male you have testicles and females has ovaries.0604

Follicle stimulating hormone is what makes the follicle develop.0610

Follicle you are going to hear more about that with the female reproductive system lessons on0616

but it is basically the cellular parts that nourish and help the ovum develop.0621

The follicle for men is you are not going to get sperm development properly without FSH follicle stimulating hormone.0631

Luteinizing hormone has a lot to do with ovulation in females.0641

The release of the egg at the right time to meet a sperm potentially that is thanks to LH or luteinizing hormone.0645

In males it has to do with proper androgen levels in maintaining male sex hormone levels where they should be.0653

One more particular hormone from the anterior or the front side of the pituitary gland you got growth hormone GH.0665

I will get to this picture in a second but growth hormone is of course very important for growing a human body.0673

You are going to see it impacting skeletal bone growth significantly specially through puberty0681

and eventually when you get to be in your 20’s typically you are done growing.0687

Females start growing usually in the late teens but males on average will still grow a little bit even in the early 20’s.0693

If you get secretion of growth hormone when you should not,0701

let us say after you have already grown to your full height, your full size in terms of height.0706

If you get secretion of growth hormone abnormally in your adult years it can call something known as acromegaly.0715

This particular gentleman Maurice T is his name but he had acromegaly.0721

It causes typically an enlargement of the jaw, the hands, and the feet to where they are abnormally large.0729

You can see from this image he does have a very large mandible.0737

That is too much secretion of growth hormone after you have already finished growing.0741

When we look at posterior side of the pituitary gland, the back end it releases two hormones.0748

These are actually synthesized or made in hypothalamus but ADH decreases the amount of water loss at the kidneys.0754

Here is a kidney.0762

The kidney is stimulated by ADH to hang onto water.0765

Let us say you have not drink enough water throughout the day, you do not want to be urinating as much because you will dehydrate your body.0770

Anti diuretic hormone levels have to do with the amount of plasma when out of fluid.0779

That is going to be noticeable in your bloodstream.0785

Things like alcohol, drinking alcoholic beverages which contains ethanol is actually going to disturb0788

the ability to release ADH properly in the bloodstream.0797

That is why somebody who is intoxicated actually tends to urinate a lot more in their urine ends up looking clear0801

when they are drunk because you are releasing way too much water out of the kidneys and part of the reason hangover so bad is dehydration.0807

Oxytocin that word literally means quick childbirth.0816

Oxytocin will have a lot to do with labor initiation also oxytocin will stimulate milk to be released out of the mammary gland.0823

There are some studies regarding how oxytocin levels are impacted by a recent mother.0834

A mother who just gave birth recently and is breastfeeding anxiety and stress which ends up affecting the hypothalamus0842

which ends up affecting the release of oxytocin can have an impact on how much milk you produce.0850

Some women will stop producing milk if they are overly stressed.0855

Some women or recent mothers if the baby is heard crying they will start lactating the milk collection will come out of the nipples just hearing the baby cry.0858

That is because that emotional response to the baby had to do with a oxytocin being released.0871

Another stimuli of oxytocin is that when they have done a test on hormone levels in really elderly couples0878

who have been married 50 or 60 years their oxytocin levels in their bloodstream are higher than average.0887

There are some theories that oxytocin is kind of like this bonding hormones0893

or neurotransmitter that helps humans connect to each other.0899

The fact that oxytocin can end up going out of breast milk into the baby can further that baby mother bond potentially.0903

The thyroid gland is the next endocrine gland we are going to discuss.0917

The thyroid glands you can see you right here in this image as sort of this interesting butterfly shape.0920

It is right below that thyroid cartilage.0928

Here is the thyroid cartilage that you might remember from the respiratory system lessons.0931

The thyroid is wrapped around the anterior surface, the front side of the trachea and is below that thyroid cartilage.0935

These two lobes as you can see 1 and 2 united by this isthmus.0943

It is that connection right in the medial mid line part of the trachea.0951

As usually about 34 g in terms of its mass or 1.2 ounces.0959

It contains follicles so if you took a cross section through there and with a microscope looked really closely0963

there are these sets of cells, cavities that are going to be surrounded in this spaces0970

you are going to see a border of tuboidal epithelium which came up in the tissues lessons.0977

Those tube shaped cells which help release the thyroid hormone into those cavities which eventually makes its way to the bloodstream.0982

How do you make thyroid hormones?0992

Something called the thyroglobulin and iodine, this particular elements are modified and combining in a way to make thyroid hormones.0994

You will see on the next slide that without iodine you cannot make thyroid hormones.1004

What is a thyroid gland doing in terms of what its releasing of the body?1010

There are two main hormones abbreviated T4 and T3.1015

It sounds like sequels to a certain movie franchise but thyroxine also known as tetraiodothyroine, here is why.1020

If we look quickly at this triiodothyroine I know it looks like a typo but that is correct.1029

Tri -- three iodo meaning 3 iodines thyronine.1035

It cointains 3 iodine ions in that particular molecule.1040

This is a shortened version, the other one is tetra meaning 4, iodothyroine.1044

It has 4 iodine ions.1049

These are released and they have huge impact on metabolism.1051

Things they actually specifically do is elevate oxygen and energy consumption which you need to do when your body needs it.1055

It helps regulate that pace of metabolism.1065

Increased heart rate and blood pressure the more of these is secrete the higher the heart rate,1069

the higher the blood pressure on average, increase sensitivity to sympathetic stimulation.1075

Somebody with too much thyroid hormones being released you can call them or you would say that they have hyperthyroidism.1079

They tend to be a little bit more fidgety especially if their sympathetic branch of nervous system was activated.1087

It stimulates red blood cell formation which is important that goes along with these.1096

If you have a need for more oxygen and heart rate is higher, blood pressure is higher, more red blood cells go along with that1102

in terms of delivering the proper amount of oxygen, tissues, and accelerate bone mineral turnover.1110

In terms of releasing some of those minerals from bones and then the rebuilding of those minerals once they have been used.1116

Those are the basic effects of the two different thyroid gland hormones.1127

The parathyroid called so because they are located on the posterior surface of the thyroid.1132

It is 4 little nodules and it was two pairs of these parathyroid glands located on the backside or the posterior surface.1140

Each is only about 1.6 g are 0.06 ounces and they secrete parathyroid hormone also abbreviated PTH.1148

What do these do?1158

Increases calcium that is the chemical abbreviation for the ion.1159

Increases calcium concentrations in body fluids specifically the blood1164

and enhances reabsorption of calcium in the kidneys and reducing the loss in urine.1169

If you actually do need to hang onto some urine, the accompanying of this parathyroid hormone along with ADH can assist with that.1175

You can see that you are getting calcium into the blood and then you are also keeping calcium in the kidneys.1188

The reabsorption thing will make more sense when you actually look at the urinary system lessons.1197

These two have to do with regulating calcium levels in the bloodstream.1203

The adrenal glands, we will look at the anatomy of all these adrenal glands are made up.1207

They are found on the superior surface of the kidney.1215

Here is that kidney, right kidney, left kidney, and they have little hats.1219

That glands are like kidney hats.1230

A slightly triangular in shape they are also known as the supra renal glands because they are above these renal organs.1233

Renal always has to do with the kidneys.1243

You can call them super renal or adrenal glands.1245

Guess what they release adrenaline.1250

Yellow pyramid shaped about 5 g mass or 0.18 ounces and each contains two main sections.1253

Let us say we took this particular adrenal gland and we cut it like a frontal cut straight through it or coronal section, you would see two layers.1262

The outside is called the cortex, the inside I am going to color it red.1276

The inside of the adrenal gland is going to be the medulla.1283

That is your adrenal gland anatomy.1294

We are going to first focus on the cortex.1301

What the cortex is doing?1304

That is the outer sets of cells of the adrenal gland.1305

They release produced aldosterone.1308

These terms here zonaglumeriolosa, zonafasciculata, and zonareticularis.1311

If you look at a micrograph of adrenal cortex you are going to see these regions from top to bottom in that part of the adrenal gland.1320

Aldosterone what does it do?1331

It targets the kidneys which are right next door.1333

Increases their absorption of sodium and water and accelerates the lost of potassium.1335

Keeping a balance between of how much sodium is in the bloodstream vs. how much potassium there is and1341

which one you are letting go of more has to do with the level of aldosterone that is being released by the adrenal cortex.1348

Glucocorticoids the main one is cortisol.1354

That is the one you can hear about mostly.1358

It targets mostly the liver.1361

It accelerates the rates of glucose synthesis and glycogen formation.1363

It is helping buildup of sugar levels and has anti inflammatory effects in terms of reducing inflammation due to your immune response.1368

Inflammation is your body’s way of getting increased blood flow specifically a lot of white blood cells to an area.1381

More glucocorticoid or cortisol being released are going to reduce that.1388

It is going to cause blood vessels to get constricted.1393

Androgens have more effect on children and women.1397

You are going to see higher levels are in more than effectiveness in kids and women not as much in men.1405

They do encourage bone and muscle growth and blood formation.1412

You can imagine that as a child growing the amount of bone muscle growth and blood formation keeps increasing.1416

That does make sense that you would see specially during growth those kinds of the facts that are needed.1424

When we look at the innermost part of the adrenal glands and what that part is doing.1432

It releases epinephrine also known as adrenaline and norepinephrine also known as noradrenaline.1439

75% of the adrenal medulla secretions are going to be the epinephrine side.1446

Norepinephrine comes from the same precursor.1452

The only difference is the nor prefix in front.1455

This has to do with the fight or flight response, in response to some kind of stressor.1458

Something that needs to be fought to maintain life or run away from it.1465

What needs to happen in your body physiologically?1471

Do that fight or flight response well here it is.1475

It increase cardiac activity, higher heart rate, increase blood pressure.1477

Your blood pressure is going to go up in terms of rocketing blood through --out your body.1482

Glycogen breakdown if your muscles are working extra hard to help you fight or run away from something you need more glucose access.1486

Breaking down glycogen and getting that sugar to the muscles is going to help with that1495

and then increase blood sugar levels accompanied with glycogen breakdown.1499

They all pertain to sympathetic activation that is fight or flight.1503

One other quick point about epinephrine, you may have heard about epi pen or epinephrine pen.1514

Somebody who gets allergic reaction to let say a bee sting or a peanut allergy their immune system will freak out1520

and cause massive vasodilatation or swelling.1527

Sometimes all over their body and they can suffocate because of the swelling in here.1530

And it cuts off their air way.1535

Those people would carry an epi pen.1538

When you stab the epi pen straight to their jeans, to their pants, into their thigh and actually inject the epinephrine,1540

that adrenaline constricts their blood vessels and will save your life.1549

They still have to go to the hospital even after that pen is used.1554

That is important for them in terms of getting their blood vessels back to a stable blood pressure.1558

If you injected an epi pen to me it will cause a heart attack.1565

Kidney hormones, the kidney also even though they are associated with urinary system they do release hormones.1570

One of them is calcitriol.1579

It is a steroid or lipidy hormone that stimulates calcium and phosphate absorption to the digestive tract.1580

The kidneys are regulating what your small intestine is doing and the important thing about that1586

is the kidneys they do have calcium and phosphate running through them.1592

The kidneys do have a sense of how much that stuff is there and the brain will stimulate the calcium1598

and phosphate hormones calcitriol to be released if the levels of calcium phosphate are too low.1607

You need to absorb a lot more of that into your bloodstream.1616

Erythropoietin you may have heard this in the news recently because of blood doping1619

but erythropoietin is a peptide hormone protein base hormone.1626

Create a response to low O2 levels causes more red blood cells to be produced.1630

Erythropoietin is impacting your bone marrow or the red bone.1640

The problem with abusing EPO if you do not need it is that it makes your blood a lot thicker.1646

Erythropoietin is going to be released has needed in a healthy person.1653

Adding more red blood cells might give you more endurance but you are more likely to get a heart attack or stroke.1657

Renin is released in response to sympathetic stimulation or decline in renal blood flow.1663

If the amount of blood flow into the kidneys is not sufficient, renin will be released in response to that.1671

Renin helps with the production of angiotensin 2 which stimulates thirst and raise your blood pressure.1678

If your blood flow is low you are probably dehydrated.1685

On so drinking more water is going to hopefully get the amount of plasma, the amount of liquid blood increased.1688

The pancreas it lies within the abdominal cavity just medial, just to the middle of the duodenum1697

which is right here at the beginning of the small intestine.1707

And inferior, below the stomach is actually slightly below the stomach but also posterior, it is right behind it.1709

Slender, pale, 20 to 25 cm long that significant, 80 g mass or .2 ounces.1723

There is actually the body and the tail of it.1731

They call this the body of the pancreas and over here is the tale.1737

In this particular lesson we are talking more about the endocrine side of it but the exocrine pancreas1741

which is mostly doing the job deals with the digestive process.1748

Secreting and digestive enzymes into the duodenum.1751

That is a major function of the pancreas in terms of digestion.1756

There are also the endocrine pancreas sending out not like the exocrine pancreas but just enzymes into the space here.1761

But sending out hormones into the bloodstream like insulin and glucagon.1770

Those particular hormones are made it was called the islets of langerhans.1774

I love this term and it is named after some scientist but the islets of langerhans are collections of cells in the pancreas1779

that produce and release the hormones in the bloodstream.1786

Pancreas physiology so what are these different pancreas hormones?1792

Glucagon which sounds a lot like glucose is produced by the alpha cells of the islets of langerhans.1796

Glucagon stimulates the breakdown of glycogen which is you are storing that polysaccharide in your liver in the muscles.1804

It stimulates the breakdown of triglycerides of fats and stimulates production of glucose in the liver.1812

Glucagon is going to be released when your blood sugar is low.1819

Let us say it is been awhile since you have eaten, you need higher blood sugar.1825

Get it out of the glycogen into the bloodstream, breakdown fats to give yourself some more building blocks to break down aerobic respiration.1830

Get even more glucose being synthesize by breaking down glycogen.1838

And glucagon does the exact opposite of insulin.1845

Insulin which is produced by the beta cells in the pancreas is the opposite affect.1852

This is actually going to cause sugar to leave the bloodstream.1858

It is going to make glycogen.1862

You actually can get a buildup of triglycerides in response to insulin and1864

also instead of glucose being released by the liver you get it out of the blood stream into cells.1870

You may have heard of insulin associate with diabetes and we will talk more about that at the end of the lesson.1878

Insulin some people have to inject it because the body either is not releasing enough insulin.1883

Maybe they have abused their pancreas with the sugar levels over many years having way too high of a blood glucose level overtime.1892

It wears out the pancreas and the body's ability to respond insulin is affected.1902

Somatostatin is actually the hormone that regulates the levels of these two.1909

Since this is produced by delta cells, somatostatin regulates the release of these two.1914

If you need to adjust the levels relative to each other, somatostatin is the one to use.1922

The pineal gland a bit about structure and what it does it lies in the posterior portion of the roof of the third ventricle deep within the cerebrum.1929

You can see that there is a ventricle in here.1940

It is hard to tell from this image but I'm going to highlight it in yellow.1944

The pineal gland is right here.1947

You can see that it is just posterior to where the thalamus and hypothalamus is as well.1953

And it is adjacent to part of the corpus callosum.1961

There is the pituitary gland, a little P shaped gland hanging from the hypothalamus but1963

the pineal gland deep within the cerebrum contain cells called pinealocytes.1970

Cyte always means cells.1974

They produce melatonin.1978

Melatonin is actually made from serotonin a neurotransmitter in the brain.1979

Melatonin is associated with sleep.1984

It regulates circadian rhythms responsible for initiating the sleepy feeling.1987

Typically for the average human when the sun is gone down and it has been dark for long enough we get sleepy.1992

If you work the night shift your brain estimate a significant adjustments and is going to take probably weeks to fully adjust1997

because it is natural for humans to be awake during the day.2005

That is what you have evolved doing.2008

There was an interesting study done on melatonin.2012

People have actually taking melatonin supplements like when on a plane because they want to knock out.2014

They want to go to sleep really quickly as soon as it takes off and wake up when the plane lands.2020

They did a placebo study showing that the percentage of people who took melatonin2026

and went to sleep faster in that sense of people who took the placebo, the fake pill that was not melatonin was about the same.2034

Melatonin being added to the brain not necessarily needed.2043

You are going to secrete melatonin and enough levels and if you are having trouble sleeping and maybe something else going on.2048

The thymus this is one of the most forgotten glands in the body.2055

I think most people do not even know it is there.2062

The thymus is located in the mediastenum, deep to the sternum.2065

Right behind the body of the sternum, below here where your trachea is, you are going to have the thymus.2069

It is very close to the pericardium of your heart.2075

You can see from Gray's anatomy this image here this is actually quite a large thymus.2078

Chances are this is in a child because it reaches its max size right before puberty.2083

It actually stops growing and if you look at somebody who is 80 years old2093

the percentage size of their thymus gland relative to their entire body size is different.2097

It seems larger in someone who is maybe 10 or 11.2103

It is 40g on average in terms of its mass 1.4 ounces.2110

It secretes thymosins and that is a blend of hormones.2117

Thymosins from the thymus gland and what do they do?2122

They regulate the production and maturation of lymphocytes.2124

A lymphocytes is a kind of white blood cell associated with your lymphatic fluid.2127

The thymus it is releasing hormones to impact the development of some cells2133

but it really has a lot to do with the immune system or lymphatic system.2139

Gonad hormones you are going to hear more about this in the reproductive lessons2143

but the testes in mails are primarily producing androgens such as testosterone.2151

Testosterone gives those classic male characteristics, a deeper voice, a larger chest, and musculature on average.2156

A slight differences in hair on the body and of course without testosterone during puberty2165

you are not going to get the genitalia becoming an adult male genitalia.2173

Ovaries in females is just the opposite side of a coin.2179

Both sets of gonads start at the same in uterus and then because of development of differences embryologically2183

you get the testes descending and becoming different.2191

The ovaries of course stay in the abdominal cavity close to the pelvis.2195

And what the ovaries do they produce estrogens like estrodyle and produce progestins like progesterone.2200

These have a lot to do with the cycle in females.2207

The menstrual cycle/ovarian cycle and of course making a female look different on average than a male.2211

Just like I mention with those on those secondary sexual characteristic beside a genitalia difference2218

in terms of the shape of the female body, voice differences, etc..2225

These hormones from the gonads are going to impact the gonads and other parts of the body of course.2231

Remember those gonadotropin hormones like FSH and LH are going to impact these particular tissues.2238

Some endocrine conditions and disorders.2249

Diabetes type 1 and 2.2252

The full name this is diabetes mellitus.2254

Type 1 they typically call the one you are born with.2259

Type 2 they call adult onset.2267

Type 1 you will see juvenile diabetes.2271

Type 2 adult onset.2273

Currently type 1 diabetes does not have a cure.2276

Type 2 can be cured.2279

Let me explain, diabetes type 1 there are various theories as to how this develops.2282

There is some evidence that there could be a virus early on in life that negatively impacts the pancreas2290

as the amount of insulin that you are leasing not enough.2296

You need insulin supplements your entire life and there are still other research being done into it.2299

There may be genetic and environmental factors involved.2305

Type 2 diabetes they call it adult onset because generally as a child this person does not have any problems2308

with their insulin levels and in regulating blood glucose.2318

But abuse of their pancreas in terms of the insulin that they are demanding their pancreas2321

to release they are eating way too much sugar throughout their life.2327

Day in and day out.2331

There is a recent study showing that just drinking much soda every day that is excess sugar2333

that your body did need and it is more likely to develop type 2 diabetes.2339

But of course there lot of factors impacted.2342

The reason why a type 2 diabetes is curable is a lot of people who have type 2 diabetes as adults tend to be overweight or obese.2344

Getting rid of that weight and changing your diet will oftentimes get rid of the symptoms of type 2 diabetes.2355

You do not even need insulin supplements anymore.2361

Diabetes insipidus is a bit different.2364

This does not apply to insulin specifically.2367

Diabetes insipidus has to do with ADH or anti diuretic hormone.2370

The symptoms of diabetes mellitus and diabetes insipidus one commonality is urinating way too much.2374

Way too many trips to the bathroom throughout the day.2381

Diabetes Insipidus is under secretion of ADH that keeps fluid in.2383

Not producing enough ADH in the kidneys you end up urinating way too.2393

You have hyper or hypoglycemia associated with diabetes.2400

Hyperglycemic means your sugar levels in your bloodstream too high and you need some insulin.2404

Hypoglycemia means sugar levels too low and you need to eat something.2409

Somebody who has been taking their insulin as a diabetic but has not been eating they are going to be hypoglycemic.2415

Insulin gets sugar out of the bloodstream.2421

You need a candy bar or drink some soda.2423

Addison disease impacts the adrenal glands primarily.2426

John F. Kenny actually had Addison's disease.2431

It has to do with the imbalance of the adrenal hormones and one of the strange side effects or signs of Addison’s disease is a bronzing of the skin.2434

I have seen some images of JFK where it looks like the illnesses is like kind a strange tan and2447

that is a sign of Addison's disease from over secretion of adrenal hormones.2453

Hyper/hypothyroidism, hyperthyroidism would be too much thyroid secretions.2459

Too much of T4 and T3.2466

Your metabolism is too speedy.2468

Hypothyroidism is not enough.2472

A lot of people with hypothyroidism tend to gain weight much more easily and2476

supplement the body with thyroid stimulators can speed up those metabolic levels.2482

Cretinism is when you are born with hypothyroidism and it is a terrible name after the babies have an appearance looking like a cretin.2489

You could say it is a juvenile at birth hypothyroidism and treatment with thyroid hormones can help with that.2502

It is something you are born with.2515

Goiter you are looking at one.2516

A goiter is way too much inflammation of the thyroid hormone.2520

You could see that it has quite a bit of swelling in this particularly lady.2526

There are ways you can produce the swelling within the thyroid gland.2530

You typically do not see this happen in a first world countries or well developed industrialized nations2535

because with medical attention and dietary knowledge and available minerals and all that you do not see goiters developing.2545

But it can happen.2556

Pituitary gigantism and dwarfism.2558

Gigantism is over activity of the pituitary gland in terms of growth hormone is going to make a person grow really tall.2560

They just keep growing unless you get surgery to fix it.2571

Someone has a tumor to the pituitary gland is doing that.2576

Robert Wadlow the tallest person ever; he was very close to 9 feet tall.2579

He had a pituitary gigantism and he died at age 22.2583

A pituitary dwarfism is the opposite, under secretion of pituitary growth hormone can make it where you do not grow tall at all.2587

There other ways you can be a little person of course.2599

There are genetic links that can sometimes lead to it but under secretion of growth hormone from the pituitary can cause it.2602

One more I want to add is IDD or iodine deficiency disorder.2609

It is easy cure and have to do with the thyroid gland because you do need iodine for those thyroid hormones.2616

Iodine deficiency disorder is most common in third world countries, underdeveloped nations because iodine is not in their diet.2624

They are not getting enough iodine.2633

And the amazing thing is the cure is like a one spoonful of iodine liquid.2634

It will give them enough reserves of iodine to do to do well.2640

It is an easy cure.2645

It is an easy fix.2646

The reason why the people in the industrialized nations like America do not see this is because of iodized salt.2647

Next time you are at the store look at the majority of the salts containers that you can buy salt in.2656

They will say iodized salt.2663

You actually add iodine to our table salt and that is an easy way to get proper levels of iodine in your body.2664

It will keep your thyroid working really well.2672

Thank you for watching