ENDOCRINE SYSTEM

Pineal gland

may control timing of reproduction and set day-night rhythms

Pituitary gland

controls other endocrine glands; regulates growth and fluid balance

Thyroid Gland

controls yissue metabolic rate; regulates calcium levels

Parathyroid Glands

regulate calcium levels (with thyroid)

Thymus

controls maturation of lymphocytes

Adrenal Glands

adjust water balance, tissue metabolism, cardiovascular and respiratory activity

Kidneys

control red blood cells production and assist in calcium regulation

Pancreas

regulates blood glucose levels

Gonads testes

support male sexual characteristics and reproductive functions

Ovaries

support female sexual characteristics and reproductive functions

Endocrine System

involved in the information business

Hormones

* (body’s chemical messengers) carry essential messages that have far-reaching effects.


* They control body processes at every level, from the energy uptake of a single cell to the whole body’s rate of growth and development.
* affect certain target tissues or organs and regulate their activities.

50

There are ___ hormones

12

Hormones are made by __ Endocrine Glands

Endocrine Glands

**have no ducts but secrete their hormones directly into the blood, by  which means they reach every cell in the body.**

The Endocrine system

sends hormones through the Circulatory system to control and coordinate body functions in much the same way as the nervous system uses tiny electrical signals.

The Endocrine system and the Nervous system

work together to integrate in the brain and complement each other, but they tend to **work at different speeds.**

Nerves

respond within split seconds but their action soon fades

Some hormones

have longer-lasting effects and act over hours, weeks, and years.

Hormones regulate processes such as:

* The breakdown of chemical substances in metabolism of what we eat and drink
* Fluid balance and urine production
* The body’s growth and development
* Sexual reproduction.

Hypothalamus

cluster of nerve cells that serves as the main link between nerves and hormones; produces “releasing factors” (regulatory hormones) that travel to pituitary gland

The hypothalamus and the pituitary gland

are part of the diencephalon region of the brain.

Connects

The hypothalamus ____ the nervous system to the endocrine system.

The hypothalamus

receives and  processes signals from other brain regions and pathways and translates them into hormones,  the chemical messengers of the endocrine system.

 Infundibulum

These hormones flow to the pituitary gland, which is connected to the hypothalamus by the _____

Some hormones

are stored in the pituitary stores for later release; others  spur it to secrete its own hormones.

The hormones released by the pituitary gland and the hypothalamus

control the other endocrine glands and regulate all major internal functions.

Thymus gland

produces three hormones involved in deelopment of white blood cells called T-cells, which function in the immune system

Progenitor cells

The thymus gland produces ______, which mature into T-cells (thymus-derived cells).

T-cells

The body uses ___ to help destroy  infected or cancerous cells.

Thymus

T-cells created by the ___ also help other  organs in the immune  system grow properly.

Primary donor of cells

The  Thymus gland is the _____ for the lymphatic system, much as bone marrow is  the cell donor for the  cardiovascular system

Adrenal Gland

Cortex (outer layer) manufactures steroid hormones that regulate metabolism of glucose, sodium, and potassium, as well as fuid balance

Medulla

(inner layer) produces adrenaline

“fight or flight” hormones

The adrenal glands regulate substance levels in the blood and release ____

The adrenal glands

are pyramid-shaped organs that sit at the top of each kidney.

Each adrenal gland consists of two structures:

an outer adrenal cortex and an inner adrenal medulla.

The adrenal cortex

is a network of fine connective  tissues that makes up most of the gland. It  secretes a range of **steroid hormones.**

Cortisol

which manages protein and  glucose levels.

Aldosterone

which adjusts our levels of  water and salt.

Androgens and estrogens

are secreted by  the adrenal cortex in small amounts by  both sexes.

The adrenal medulla

(inside the gland)  produces epinephrine and nor-epinephrine  (NE).

Epinephrine and nor-epinephrine  (NE).

These chemicals promote “fight-or-flight,” the body’s initial response to stress.

Slightly higher

The left kidney is located ____ than the right kidney due to the larger  size of the liver on the right side of the  body

Kidney

secretes erythropoietin, which stimulates production of red blood cells in bone marrow

2 hormones made by kidneys

1. vitamin D
2. Erythropoietin

Vitamin D

essential for a number of different functions in the body.

Inactive

Most of the vitamin D that is in the blood is _____ and it is modified by the kidney and other tissues to activate it.

Active vitamin D

stimulates the uptake of calcium from food, is important for the maintenance of healthy bones, and also helps to regulate the response of the immune system to infection.

Erythropoietin

produced when oxygen levels in the blood are low.

Bone marrow

It acts in ______ to stimulate the production of mature red blood cells and to maintain healthy oxygen levels in our tissues.

Intestines

like stomach, makes hormones that stimulate production or release of enzymes that aid digestion

Ovary

The two ovaries manufacture the female sex hormones, estrogen and progesterone , which stimulate egg ripening and thickening of the uterine wall respectively

The main sex glands

are the **ovaries in females and testes in males.**

The sex hormones

produce stimulate  the production of eggs and sperm  respectively and influence the early  development of the embryo into a boy or  girl.

Low

After birth, the circulating levels remain __ until puberty.

The testes

increase their output of androgens (male sex hormones),  such as testosterone.

Estrogens and progesterone.

The ovaries produce more  ____

Pineal gland (pineal body)

Pea-sized gland in middle of brain; makes melatonin and influences sexual development

Melatonin

a hormone important in a body rhythms such as the sleep-wake cycle

At the back of the diencephalon region in the brain.

The pineal gland is small and pine cone- shaped, (which is how it got its name)  located _____

The hormone melatonin.

At night, in the absence of light, the pineal gland secretes _____

both circadian  (daily) and seasonal patterns.

Melatonin regulates the body’s sleep patterns in _____

Photo receptors in the retina send signals

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In the morning, when light hits the eye,  ____ to the pineal gland, which then **decreases** melatonin production and we wake up.

Pituitary gland

called the “master gland” controls many other endocrine glands

Most influential gland

The pituitary is the ______ in the endocrine  system.

2

The pituitary gland is a __ distinct glands in one

7

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The front or anterior lobe of the pituitary gland manufactures __ major hormones and releases them into the bloodstream.

3

Behind it is the posterior (back) lobe which receives its two main hormones from the hypothalamus, which lies above it and then it releases _ hormones

7 major hormones present in the anterior lobe of pituitary gland

1. Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) **(OVARIES)**
2. Follicle-stimulating hormone (FSH) luteinizing hormone (LH) **(TESTIS)**
3. Growth Hormone (GH) **(BONES AND TISSUES)**
4. **Melanocyte-stimulating hormones (MSH) (SKIN)**
5. Prolactin (PRL) (MAMMARY GLANDS)
6. Adrenocorticotropic hormone (ACTH) (ADRENAL CORTEX)
7. Thyroid-stimulating hormone (TSH) (THYROID GLAND)

3 Hormones present in the posterior lobe of pituitary gland

1. Anti-diuretic hormone (ADH) (KIDNEY)
2. Oxytocin (UTERUS SMOOTH MUSCLE)
3. Oxytocin (MAMMAARY GLANDS)

Thyroid gland

controls the rate of metabolism, including maintenance of body weight, rate of energy use, and heart rate;

Store its hormones

Unlike other endocrine glands, thyroid glands can _____

The thyroid and parathyroid glands

increase metabolism and regulate calcium levels

The thyroid gland

sits in the throat region, just  below the larynx, served by large arteries with many branches and a dense network of capillaries

The hormones that the thyroid glands secrete travel in the  bloodstream throughout the body to:

* Increase metabolism
* Regulate glucose use


* Protein synthesis
* Nervous system development

Calcitonin

helps  maintain blood calcium homeostasis by  causing calcium to be removed from the  blood and deposited into bones when blood  (calcium) levels are too high.

Parathyroid glands

On the posterior (back) surface of the thyroid sit much smaller, separate glands called ___

4 parathyroid glands

a  superior and inferior pair on the left and right  sides of the thyroid.

Parathyroid hormone (PTH)

* stimulates bones to release calcium into the blood when blood (calcium) levels are low.
* also causes the kidneys to reduce calcium secretion into urine to further elevate calcium  levels in the blood.

Calcitonin and Parathyroid stimulating hormone

act in  complementary ways to maintain blood  calcium homeostasis, which is one of the most  tightly controlled physiological parameters in  the body.

Iodine

an element that's required for  the thyroid gland to produce thyroid  hormones.

Dietary sources

Since the body does not produce iodine on  its own, it needs to come from ___ and striking the right balance is key.

Importance of Iodine

* When you consume iodine, it is quickly  absorbed and entered into your bloodstream.
* Your thyroid, which has tiny cells that capture  the circulating iodine, takes in and oxidizes it  so it can begin to be used to create T3 and T4—thyroid hormones that make their  way throughout the body to regulate  metabolism and ensure healthy functioning of  the heart, brain, and other organs.

Heart

Produces hormone called atriopeptin (atrial natriuretic factor, ANF or atrial natriuretic peptide, ANP);

Atriopeptin

reduces blood volume and pressure as well as helps to regulate fluid balance

Stomach

Makes hormones that stimulate production or release of enzymes that aid digestion

The gut hormones work in association  with the gut’s extensive nervous  system (enteric nervous system) and  play a coordinating role in:

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* The control of appetite
* The digestion of food
* The regulation of energy balance
* The maintenance of blood glucose  levels.

Gut hormones

continuously sends information  to the brain regarding the quality and  quantity of the food that is consumed.

Ghrelin

is produced in the stomach, and its function is to tell the brain that the body has to  be fed.  It increases appetite.

Gastrin

is produced in the stomach when it is stretched. It stimulates the release of gastric  juice rich in pepsin and hydrochloric acid.

Secretin

is produced in the duodenum and has the effect of stimulating the pancreas to  produce alkaline secretions as well as slowing the emptying of the stomach.

Secretin

produced in the duodenum. It reduces appetite, slows down the  emptying of the stomach and stimulates the release of bile from the gall bladder.

Peptide YY (PYY)

is produced in the last part of the small intestine known as the ileum as  well as parts of the large intestine. It plays a role in slowing down the passage of food along  the gut, which increases the efficiency of digestion and nutrient absorption after meal.

Glucagon-like peptide 1 (GLP-1)

is produced in the small intestine and colon and has  multiple actions including inhibition of gastric emptying and appetite as well as the  stimulation of insulin release.

Pancreas

bears clusters of cells, known as islets of Langerhans, which produce two hormones, insulin and glucagon. Part of the digestive system

Insulin and glucagon

respectively lower and raise blood glucose levels as part of the body’s energy control mechanism

Pancreatic juice

Pancreas excretes ____ into the small intestine via  the pancreatic duct.

Pancreatic islets (or islets of  Langerhans)

Scattered within the pancreas there are also tiny cell clusters called ___ that release hormones into the  bloodstream.

Pancreatic islets

make up less than 2% of pancreatic tissue,  but their specialized cells regulate blood glucose levels  (or blood sugar).