Anatomy of the Endocrine System

Summary

This script delves into the endocrine system, highlighting its role alongside the nervous system in maintaining homeostasis. It explains how endocrine glands release hormones into the bloodstream to target specific cells, influencing functions such as energy storage, growth, and stress response. The video distinguishes between exocrine and endocrine glands, emphasizing the latter's ductless secretion method, and introduces the 10 major endocrine glands, setting the stage for further exploration of their hormonal roles.

Takeaways

• 😀 The endocrine system works alongside the nervous system to maintain homeostasis in the body.
• 🚀 The endocrine system exerts its influence more slowly than the nervous system, through the release of hormones into the blood.
• 🌟 Endocrine glands produce hormones that target specific cells and have various effects throughout the body.
• 🔍 The process of hormone action involves secretion into interstitial fluid, diffusion into capillaries, and binding to specific receptors on target cells.
• 🔄 Hormone-receptor binding can lead to changes in target cells, such as altering cell membrane permeability, enzyme activation, or stimulating mitosis.
• 🌱 Hormones play a crucial role in energy storage and utilization, as exemplified by insulin and glucagon's regulation of blood glucose levels.
• 👶 Hormones are essential for growth, puberty, maturation, and development of sex cells, as well as pregnancy and birth.
• 🛡 The body's response to stress, such as the fight or flight response, is controlled by hormones like adrenaline.
• 🔄 Receptors for hormones can be upregulated or downregulated depending on the hormone concentration, affecting the cell's sensitivity to the hormone.
• ⚖️ The endocrine and exocrine glands differ in their secretion methods, with endocrine glands releasing hormones directly into the bloodstream and exocrine glands secreting into ducts or body cavities.
• 📍 The major endocrine glands include the pituitary, pineal, thyroid, parathyroid, adrenal glands, pancreas, ovaries (in females), and testes (in males).

Q & A

What is the primary role of the endocrine system in the body?

The primary role of the endocrine system is to help maintain homeostasis, along with the nervous system, by releasing hormones into the bloodstream that target specific cells and have various effects.

How does the endocrine system differ from the nervous system in terms of its response speed?

The endocrine system acts more slowly compared to the nervous system. While the nervous system acts quickly through electrical impulses or action potentials, the endocrine system exerts its effects through the gradual release of hormones into the blood.

What are hormones and how do they function within the body?

Hormones are chemicals released into the blood by endocrine glands. They travel through the bloodstream, bind to receptors on target cells, and cause a specific cellular response, thus having their effect.

Can you explain the process of how a hormone is released and travels to its target cell?

An endocrine gland secretes a hormone into the interstitial fluid, which then diffuses into a capillary. The hormone travels through the bloodstream until it reaches a target cell with a specific receptor. The hormone binds to this receptor, causing a change in the target cell that allows the hormone to exert its effect.

What is the concept of down regulation in the context of hormone-receptor interactions?

Down regulation refers to the decrease in the number of receptors on a target cell when there is an excess of a particular hormone. This makes the target cell less sensitive to the hormone, preventing it from having too strong of an effect.

What is the opposite process of down regulation called, and what does it involve?

The opposite of down regulation is called up regulation, which involves an increase in the number of receptors on a target cell when there is a deficiency of a particular hormone. This makes the target cell more sensitive to the hormone.

How does the hormone adenosine affect our daily energy levels and sleep patterns?

Adenosine is a hormone that builds up as we exert energy throughout the day. When it binds to its receptors, it makes us feel tired and sleepy. The loss of adenosine by the end of the day is thought to trigger the need for sleep.

What is the relationship between caffeine and adenosine receptors, and how does this affect our alertness?

Caffeine, structurally similar to adenosine, can bind to adenosine receptors, preventing adenosine from binding and causing its fatigue-inducing effect. This is why caffeine can make us feel more alert and awake.

How do hormones influence the storage and utilization of energy in the body?

Hormones, such as insulin and glucagon released from the pancreas, play a significant role in energy storage and utilization. Insulin facilitates the storage of glucose as glycogen, while glucagon triggers the breakdown of glycogen to release glucose back into the blood for energy.

What are the main functions of the endocrine system in maintaining homeostasis?

The endocrine system helps maintain homeostasis by influencing energy storage and utilization, regulating growth and reproduction, and controlling body responses to external stimuli, such as the stress response.

Can you describe the difference between exocrine and endocrine glands in terms of their secretion methods?

Exocrine glands secrete their products into ducts that lead to body cavities or the outer surface of the body. In contrast, endocrine glands secrete hormones directly into the interstitial fluid, from where they diffuse into the bloodstream and are carried to target cells throughout the body.

What are the 10 major endocrine glands mentioned in the script, and what is unique about the pancreas among them?

The 10 major endocrine glands are the pituitary gland (anterior and posterior), pineal gland, thyroid gland, parathyroid glands, adrenal glands, pancreas, ovaries (in females), and testes (in males). The pancreas is unique because it has both exocrine and endocrine functions, releasing hormones like insulin and glucagon for its endocrine role, and digestive enzymes for its exocrine role.

Outlines

00:00

🌟 Endocrine System Overview and Function

The first paragraph introduces the endocrine system, highlighting its role alongside the nervous system in maintaining homeostasis. It explains that the endocrine system operates more slowly by releasing hormones into the bloodstream. The paragraph also clarifies the distinction between exocrine and endocrine glands, emphasizing that endocrine glands produce hormones that target specific cells. The learning objectives include understanding the anatomy of the endocrine system, describing its function, and identifying the 10 major endocrine glands. Hormones are described as chemical messengers that bind to receptors on target cells to elicit specific responses.

05:02

🔍 Hormone Mechanism and Receptor Dynamics

This paragraph delves into the process of hormone release and action. It details how hormones are secreted by endocrine glands into the interstitial fluid and then into the bloodstream, where they travel to target cells with specific receptors. The concept of receptor specificity is introduced, explaining how hormones can only affect cells with the appropriate receptors. The paragraph also discusses the regulatory mechanisms of receptor numbers, including down regulation to reduce sensitivity when hormone levels are high and up regulation to increase sensitivity when hormone levels are low, using examples such as adenosine and caffeine to illustrate these processes.

10:02

🏋️‍♂️ Hormonal Influences on Energy, Growth, and Stress Response

The third paragraph discusses the various functions of the endocrine system, focusing on its role in energy storage and utilization, growth and reproduction regulation, and the body's response to external stimuli. It provides examples such as insulin and glucagon's role in blood glucose management, and the influence of hormones on puberty, sex cell development, and pregnancy. The paragraph also touches on the stress response, explaining the fight or flight mechanism triggered by adrenaline, which prepares the body for stressful situations by increasing heart rate and blood flow, and facilitating glycogen breakdown for energy supply.

15:04

🔬 Effects of Hormones on Target Cells

This paragraph explores the specific effects hormones have on target cells once they bind to their receptors. It outlines several mechanisms, including changes in cell membrane permeability, activation or deactivation of enzymes, alterations in secretory activity, and stimulation of mitosis. Each mechanism is exemplified, such as the anti-diuretic hormone's effect on water reabsorption in the kidneys and the role of growth hormone in stimulating cell division for growth.

20:05

📚 Identification of Major Endocrine Glands

The final paragraph provides an overview of the major endocrine glands, distinguishing between those that are specific glands and those that are tissues within other organs. It describes the pituitary gland, pineal gland, thyroid gland, parathyroid glands, adrenal glands, pancreas, ovaries, and testes, detailing their locations and noting the dual exocrine and endocrine functions of the pancreas. The paragraph sets the stage for further discussion on the hormones released by these glands and their effects in subsequent lectures.

Keywords

💡Endocrine System

The endocrine system is a collection of glands and tissues that produce hormones to regulate various bodily functions. It plays a critical role in maintaining homeostasis alongside the nervous system. In the script, it is described as acting more slowly than the nervous system, exerting its effects through the release of hormones into the bloodstream rather than through electrical impulses.

💡Hormones

Hormones are chemical messengers released into the bloodstream by the endocrine glands. Each hormone targets specific cells and has unique effects. The script explains how hormones are secreted, travel through the blood, and bind to receptors on target cells to elicit a response, exemplified by the processes of insulin and glucagon release from the pancreas.

💡Homeostasis

Homeostasis refers to the body's ability to maintain a stable internal environment despite external changes. The endocrine system, along with the nervous system, helps to achieve this by regulating various physiological processes. The script mentions that the endocrine system's role in homeostasis includes influencing energy storage and utilization, growth and reproduction, and responses to external stimuli.

💡Exocrine Glands

Exocrine glands are glands that secrete their products into ducts leading to body cavities or the outer surface. They are contrasted with endocrine glands in the script, with examples provided such as sweat glands, oil glands, and digestive glands, which are not part of the endocrine system.

💡Endocrine Glands

Endocrine glands are ductless and secrete hormones directly into the interstitial fluid, from where they diffuse into the bloodstream. The script distinguishes these from exocrine glands and lists several major endocrine glands, including the pituitary, thyroid, adrenal glands, and the pancreas, among others.

💡Pituitary Gland

The pituitary gland, often referred to as the 'master gland,' is an endocrine gland located beneath the hypothalamus. It is divided into the anterior and posterior pituitary, each releasing different hormones. The script describes its anatomical location and its role in releasing various hormones that regulate other endocrine glands.

💡Pineal Gland

The pineal gland is an endocrine gland that has connections with the visual system and is located near the occipital lobe of the brain. It is known for producing the hormone melatonin, which regulates sleep-wake cycles. The script mentions its location and its ties to the visual system.

💡Thyroid Gland

The thyroid gland is an endocrine gland situated in the front of the neck that produces hormones regulating metabolism. The script describes its location and function, including the release of thyroid hormones in response to Thyroid Stimulating Hormone (TSH) from the pituitary gland.

💡Adrenal Glands

The adrenal glands are endocrine glands located on top of each kidney. They are composed of the adrenal cortex and adrenal medulla, each with distinct functions and hormone production. The script explains their anatomical position and the dual nature of their structure.

💡Parathyroid Glands

The parathyroid glands are four small endocrine glands located on the posterior surface of the thyroid gland. They produce parathyroid hormone, which regulates calcium levels in the blood. The script identifies their location and function in calcium homeostasis.

💡Pancreas

The pancreas is a dual-function gland with both exocrine and endocrine roles. As part of the endocrine system, it produces hormones like insulin and glucagon, which regulate blood sugar levels. The script highlights its unique role in both digestion and hormone production.

💡Ovaries and Testes

The ovaries and testes are the primary reproductive endocrine glands in females and males, respectively. They produce sex hormones, such as estrogen and progesterone in females, and testosterone in males. The script mentions their role in producing sex hormones and their location in the body.

Highlights

The endocrine system, alongside the nervous system, plays a crucial role in maintaining homeostasis through the release of hormones.

The endocrine system exerts its effects more slowly than the nervous system by releasing hormones into the bloodstream.

Endocrine glands produce and release hormones that target specific cells and have various effects throughout the body.

Hormones are chemical messengers that bind to receptors on target cells, causing a specific cellular response.

The process of hormone release and action involves diffusion from interstitial fluid into capillaries and then binding to target cell receptors.

Receptor specificity is crucial for hormones to have an effect, with each hormone fitting its specific receptor like a lock and key.

Hormone-receptor binding can lead to various cellular responses, including changes in membrane permeability and protein synthesis.

Receptor numbers can fluctuate through processes like down regulation, reducing sensitivity when hormone levels are high, and up regulation, increasing sensitivity when hormone levels are low.

Adenosine and caffeine illustrate the dynamic interaction between hormones and their receptors, affecting alertness and sleepiness.

The endocrine system is integral in energy storage and utilization, exemplified by insulin and glucagon's roles in blood glucose regulation.

Hormones significantly influence growth, reproduction, and development, including puberty, maturation of sex cells, and pregnancy.

The body's response to stress is controlled by hormones like adrenaline, preparing the body for fight or flight.

Exocrine and endocrine glands are distinguished by their secretion methods, with exocrine glands using ducts and endocrine glands secreting directly into interstitial fluid.

Major endocrine glands include the pituitary, pineal, thyroid, parathyroid, adrenal, pancreas, ovaries, and testes, each with specific hormonal functions.

The pituitary gland is composed of the anterior and posterior regions, each releasing different hormones with distinct functions.

The adrenal glands have two distinct regions, the adrenal cortex and medulla, each with unique hormonal secretions.

The pancreas has both exocrine and endocrine functions, releasing insulin and glucagon for blood glucose regulation.

The ovaries and testes produce sex hormones essential for sexual development and reproduction.

Transcripts

foreign

beyond the basics and the first organ

system that we're going to cover in

systemic anatomy and physiology is the

endocrine system

so along with the nervous system the

endocrine system plays a role in almost

all of our body's functions by helping

to maintain homeostasis

however where the nervous system acts

quite quickly through electrical

impulses or action potentials the

endocrine system exerts its effects more

slowly by releasing hormones into the

blood

as you can see depicted in this image

here the endocrine system is made up of

organs or tissues called glands

and it is these glands that produce and

release hormones

hormones are chemicals that are released

into the blood and would each Target a

different cell

and have different effects

so we have three learning objectives to

look at the anatomy of the endocrine

system to First describe the function of

the endocrine system and briefly how

endocrine glands and hormones work

to distinguish between exocrine and

endocrine glands

and then to Simply identify the 10 major

endocrine glands that we're going to

focus on in this unit

so starting a learning objective number

one to describe the function of the

endocrine system

so as I briefly mentioned the endocrine

system is made up of a collection of

endocrine glands or endocrine tissues

which are scattered throughout the body

endocrine glands secrete hormones into

the bloodstream

hormones travel through the bloodstream

and bind to receptors on target cells

and it is this binding of a hormone to a

receptor that causes a cell to respond

in a specific way

and for the hormone to have its effect

so taking a look at that process a

little more closely and we have our

endocrine gland or our secreting cell in

yellow here

and these green circles are our hormone

so our endocrine glands will either just

secrete or produce and secrete our

hormones

they secrete those hormones into the

interstitial fluid which surrounds our

endocrine gland

from the interstitial fluid that hormone

will then diffuse into a capillary which

surrounds all of our endocrine glands

and that hormone can now travel

throughout the body in the bloodstream

that hormone will travel throughout the

body until it reaches a Target cell so

we have a Target cell here and a Target

cell here

and what makes a cell a Target cell is

that it has a receptor that is specific

to that particular hormone

so see how this round hormone can fit

into this round part of the receptor

here perfectly that's because these

receptors and hormones are specific to

one another

if a cell does not have a receptor for a

particular hormone that hormone cannot

have an effect on that cell

so our hormones are released from our

endocrine glands they travel through the

interstitial fluid into our capillary

they travel around the body in the

bloodstream they then diffuse out of the

capillary into the interstitial fluid

they will bind to a receptor on a Target

cell that is specific to that hormone

and that binding to a receptor is what

causes some change in this target cell

that allows that hormone to have as an

effect

now in this example we have receptors

that sit on the surface of the plasma

membrane

we can also have receptors that sit

within the cell just underneath that

plasma membrane

now I just wanted to give you one

example of a couple of different things

that can happen to our receptors within

the body I haven't got a lot of words on

this slide because this is not something

that I will test you on but I just want

you to be aware of this process so like

any of the other proteins in a cell

receptors are constantly being produced

or broken down

so generally a Target cell will have

between two and ten thousand receptors

for a particular hormone but this can

change at any moment in time

so for example if we have a lot of a

particular hormone

the number of receptors on a Target cell

May decrease

this effect is called down regulation

and it makes a Target cell less

sensitive to a hormone so we've got too

much of a particular hormone we don't

want that hormone to have such a big

effect so we down regulate the number of

receptors so that cell is less sensitive

one example of this is when certain

cells of the testes are exposed to a

high concentration of luteinizing

hormone we will then down regulate the

number of luteinizing hormone receptors

that those cells contain

in contrast when a hormone is deficient

so there's not much of that hormone in

circulation we can actually increase the

number of receptors so this process is

known as up regulation

and it makes a Target cell more

sensitive to a particular hormone

now this specific example that I've got

on a slide here is one that I think most

of us will be somewhat familiar with so

in the green we have a hormone called

adenosine

and adenosine is a hormone or also acts

as a neurotransmitter which we release

throughout the day as we exert energy so

we kind of wake up in the morning and we

don't have much adenosine as we go about

our day and we exert energy more and

more adenosine is circulating throughout

the human body what adenosine does when

it binds to its receptors is it makes us

feel tired and sleepy so the thinking is

that loss of adenosine by the end of the

day is what actually makes us want to go

to bed

now we also have this molecule called

caffeine which I'm sure most of us will

be aware of

and caffeine in structure is very very

similar to what our hormone adenosine

looks like

what this means is that our caffeine

molecule can actually bind to our

adenosine receptor

and when it's binding to our adenosine

receptor adenosine can no longer longer

bind to its own receptor and have its

fatiguing effect

so that's why when we have caffeine if

you have a coffee in the afternoon it

can kind of wake you up because that

adenosine can no longer bind to its

receptor and have that fatiguing or that

sleepiness kind of effect or feeling

what happens though when we have a lot

of caffeine is that there's lots of

caffeine or lots of caffeine molecules

circulating throughout the body so our

brain decides to upregulate the number

of adenosine receptors so now we have

lots of adenosine receptors so more

adenosine confined to those receptors so

we feel more and more sleepy and now we

need more and more caffeine to actually

bind to The receptors so adenosine can't

bind to its own receptors and have that

alerting or that energizing effect

so I just kind of want to point out that

we have our receptors but that number of

receptors isn't consistent it can

actually fluctuate depending on the

concentration of that hormone within the

blood as well as the concentration of

other hormones or molecules present uh

present within our circulation

so now that we have I guess a general

understanding of how hormones work so

they're released from our endocrine

glands they then travel throughout the

blood to our Target cell they need to

bind to a receptor to then have their

effect we need to talk about the

functions of the endocrine system and

the I guess the effects that the

hormones have

so first and foremost the endocrine

systems role is to help maintain

homeostasis along with the nervous

system so all of these points underneath

maintain homeostasis are simply examples

of how we actually do that

so the first example or function that

we've got here is that hormones can

influence the storage and utilization of

energy

so the best example of that is the

release of insulin and glucagon from the

pancreas

so let's say we have a big lunge

our blood glucose levels increase

the pancreas will then release insulin

which causes the glucose to be taken out

of the blood and stored as glycogen in

the liver in our muscles

and now we have a lower blood glucose

concentration if the opposite occurs so

lunch was a number of hours ago and our

blood glucose concentration is now going

down our pancreas will release glucagon

which causes the breakdown of glycogen

from our liver and our muscles which

then gets released back into the blood

so we have an increase in our blood

glucose concentration and we can use

those that glucose as energy so our

hormones play a really big role in the

storage and the utilization of our

energy

hormones can also affect the regulation

of growth and reproduction

so both in the next lecture and when we

get to the reproductive system we're

going to talk about a whole range of

hormones that can influence growth

puberty maturation development of our

sex cells so eggs and sperm as well as

pregnancy and birth and all of these

processes are driven by hormones

our last example is the control of body

responses to external stimuli and a

really nice example of this is stress

so you may have heard of the fight or

flight response this is an activation of

the sympathetic nervous system and it

occurs when our body encounters a

stressful situation now our body

considers stress something like

exercising but it can also consider you

know an emergency situation as something

stressful now what happens in these

situations is that our body releases the

hormone adrenaline

and this helps us prepare for that

stressful or that emergency situation so

for example our heart might start

beating faster

we might have increased blood flow to

our working muscles

we might also have breakdown of glycogen

in the liver so that we have a big

supply of glucose in the blood that we

can use as energy

so that those flight and sorry fight or

flight responses are often controlled by

different hormones

now

the way that the endocrine system can

impart all of those functions that we

talked about on the previous slide is

down to the effect that the hormone has

on their target cells so we kind of

looked at brief or more General

functions of the endocrine system but

exactly how do those hormones affect the

target cells which allow for those

effects or allow for those functions so

again there's a whole range of examples

and I've just listed five here but one

example is that when a hormone binds to

its receptor it can change the cell

membrane permeability so how easily

things can pass through that cell

membrane

an example of that is anti-diuretic

hormone so when that hormone binds to

the tubules in the kidneys it allows

water to more easily pass through the

cell membrane so that we can reabsorb

more water and put it back in the blood

we can also have the production or the

synthesis of protein or other regulatory

molecules when a hormone binds to its

Target cell

so for example when thyroid stimulating

hormone binds to The receptors on the

thyroid gland it stimulates the

production of our thyroid hormones which

are T3 and T4 and we'll talk about these

more in the next lecture

The Binding of a hormone can also cause

activation or deactivation of an enzyme

so when most of our peptide hormones

bind to The receptors they activate

second messages within the cell which

then activate or deactivate enzymes

within that cell

The Binding of a hormone can also alter

their secretory activity of a cell so

for example the hormone gastrin can

stimulate the secretion of gastric acid

or stomach juices by the parietal cells

in the stomach

and lastly The Binding of a hormone to

its receptor can also stimulate mitosis

or cell division

a nice example of that is growth hormone

which has lots of target cells in all of

our tissues so our tissues our organs

our bones our muscles

and when that hormone binds to the

receptor it stimulates cell division

which then obviously results in growth

so moving on from the functions and the

effects that our hormones have on a cell

when they bind to their receptors and

learning objective number two is to

distinguish between exocrine glands and

endocrine glands

So within the human body we have two

types of glands we have exocrine glands

and we have endocrine glands

exocrine glands with EXO meaning outside

and cream or crime meaning to secrete

secrete their products into ducts

and they carry those secretions into

body cavities

into the Lumen of organs which is just

like the inside of an organ or to the

body's outer surface

so for exocrine glands think about your

sweat glands your oil glands your mucous

glands and your digestive glands

for our endocrine glands so with Endo

meaning within and crying or crin again

to meaning to secrete

these uh

types of glands secrete their products

which are hormones into the interstitial

fluid surrounding the endocrine gland

instead of secreting them into ducts so

endocrine glands don't have any ducts

from the interstitial fluid those

hormones diffuse into the blood in the

capillaries and the blood carries them

to the target cells throughout the body

now because of their dependence on the

cardiovascular system or the blood to

distribute their products our endocrine

glands are some of the most vascular

tissue in the whole body

now some of the endocrine glands which

you may have heard about before and that

we'll talk about in this lecture are the

pituitary glands

our thyroid gland our adrenal and our

pineal glands

we also have

endocrine tissues which are not

exclusively classified as endocrine

glands but contain cells that will

actually secrete hormones so together

with our specific endocrine glands these

do make up our endocrine system and so

these are tissues such as the

hypothalamus

the pancreas the ovaries and testes the

kidneys the stomach the liver and the

small intestine

so to give you a bit of a visual and a

bit of a recap we have our exocrine

glands on the left and our endocrine

glands on the right remember our

exocrine glands have ducts which is just

this little bit here which then

transfer the secretions to wherever

they're going to go

our endocrine glands don't have any

ducts remember they secrete the hormones

into the interstitial fluid which is

like this part here which then diffuse

into the capillaries which will be

surrounding our endocrine glands

so in this example here this looks like

a sweat gland

so the sweat will be produced by the

exocrine gland taken into the duct and

then secreted to the cells outer surface

or the outer surface of the body

on our right side we have our endocrine

glands so the hormones are produced in

that gland

secreted into that interstitial fluid

diffused into the blood and then they

travel throughout the bloodstream to the

target cells

now the final learning objective for

this lecture which is only a nice short

one is to Simply identify the major

endocrine glands so this is something

that we will go over in the next lecture

we will also go over in Labs but the

first thing that I want you to know is

to be able to identify these major

endocrine glands before that we then go

on to talk about what hormones they

release and then what those hormones

actually do

so when we talk about the major

endocrine glands these are the 10 glands

that we are referring to so some are

specific glands some are just tissues

within other organs that secrete

hormones

so starting from the top and we have our

pituitary gland so our pituitary gland

is this structure here

without sounding too crass it kind of

looks a little bit like a pair of

testicles in a full image of the brain

it is this little structure here

now

showing a little bit of a close-up image

of our pituitary gland our pituitary

gland sits underneath our hypothalamus

and it's made up of two distinct regions

which each function slightly differently

and release different hormones so this

anterior portion or the portion to the

front funnily enough is called our

anterior pituitary gland the posterior

portion or the bit which is more towards

the back is our posterior pituitary

gland

so the whole structure is our pituitary

gland the bit at the front is our

anterior pituitary the bit at the back

is our posterior pituitary

moving down we then have our Pioneer

gland so if our pituitary gland is kind

of at the front of the brain here our

Pioneer gland is more at the back here

so you can see it's just that little

white structure there

now we're going to talk more about the

function of the pineal gland in the next

lecture but I just wanted to point out

that the pineal gland actually has some

really strong ties with the visual

system

which is potentially why it's so close

to our occipital lobe at the back of the

brain here which is where we house our

our primary visual cortex

we then have our thyroid gland so our

thyroid gland sits on the anterior

surface of the throat or the neck it

sits just inferior or just underneath

the thyroid cartilage which is the

cartilage which protects our voice box

and in males is known as the Adam's

apple

and then on the back of our thyroid

gland so if this is our thyroid gland

here we have these four dots in Grain

and these are our parathyroid glands

so we've had the pituitary gland

the pineal gland the thyroid gland and

then these four parathyroid glands which

sit on top of that thyroid gland

moving on we then have our adrenal

glands so we have two adrenal glands one

sits on top of each kidney it's a little

bit hard to see in this image here but

if we zoom in for a closer look here

we've got our two kidneys here these

little hats

are our adrenal glands

and much like our pituitary gland our

adrenal gland is made up of two distinct

regions that each have different

functions and release different hormones

so we are going to need you to be able

to identify each of those two regions

we have the adrenal cortex which is this

outer region here

so any time you see the word cortex in

anatomy and physiology you know it's

going to be the outermost layer I think

the cerebral cortex it's the outermost

layer of the brain so this is our

adrenal cortex

this inner portion here is our Adrenal

medulla so maybe middle medulla our

Adrenal medulla is this portion here

we then have the pancreas and the

pancreas is this little structure here

which is again a little bit hard to see

on this image but we will take a closer

look when we talk more about the

pancreas I kind of think it looks a

little bit like a cob of corn it's kind

of a bubbly yellowy color

and the pancreas is a little bit special

because it has both exocrine and

endocrine functions so when we talk

about the endocrine system we're going

to talk about its endocrine function and

how it releases insulin and glucagon but

then when we get to the gastrointestinal

system we're going to talk more about

its exocrine function

we then have our ovaries so in our

female

example we have our two ovaries here

which sit either side of our uterus

these produce our female sex hormones

and then in males we have our testes

which actually sit external to the body

covered by the scrotum

and they mostly produce our male sex

hormones

so these are our 10 hormones or sorry

our 10 endocrine glands that we're going

to be focusing on in the next lecture

when we talk about the physiology of the

endocrine system we had our pituitary

gland at the top here which is broken

into our anterior and our posterior

pituitary gland

we had the pineal gland which sits just

posterior to the pituitary gland

we have our thyroid gland which is this

bit on the front of your neck

we had the parathyroid gland which these

four green dots on the back of the

thyroid gland

we have our adrenal glands which are the

two hats that kind of sit on top of each

kidney

the pancreas which is the one I said

looks a bit like a cob of corn and that

sits kind of underneath the stomach and

the liver and then we have our ovaries

which we find in a female population

and our testes which we find in a male

population

so now that is the anatomy of the

endocrine system when we come to the

physiology of the endocrine system we

will talk more about these glands

specifically what hormones they release

and then the effect of those hormones on

their target cells when those hormones

bind to their receptors

thank you very much