The endocrine system

Question 1

The endocrine system is a control system with 3 main functions. What are they?

Answer 1

Maintenance of homeostasis
To help the body react properly to stress
Regulation of growth and development including sexual development and reproduction

Question 2

How is the system organised?

Answer 2

Endocrine glands

Hormones

Question 3

What are endocrine glands?

Answer 3

Tissues and organs that secrete hormones

Question 4

What are hormones?

Answer 4

Chemical messengers released into the blood stream

Question 5

Where do hormones travel?

Answer 5

Travel to all parts of the body, but only effective in specific target cells

Question 6

What do hormones work together to control?

Answer 6

Feedback mechanisms

Question 7

Name the endocrine organs/glands

Answer 7

Hypothalamus
Pituitary
Pineal
Thymus
Thyroid
Parathyroid
Adrenal
Pancreas
Gonads

Question 8

How many hormones does the hypothalamus produces and how many regulate the anterior pituitary?

Answer 8

9

7

Question 9

What are the two hormones that are released into the posterior pituitary?

Answer 9

Oxytocin and antidiuretic

Question 10

What is also known as the master gland as it controls the majority of other endocrine glands?

Answer 10

Pituitary

Question 11

Where is the pituitary located and what are the two lobes?

Answer 11

Below the hypothalamus in Sella turcica of sphenoid

Anterior Adenohypophysis
Posterior Neurohypophysis

Question 12

What are the pituitary hormones?

Answer 12

Thyroid
Melanocyte
Prolactin
Growth hormone
Gonadotropins
Adrenocorticotrophic

Question 13

What does the pineal gland release?

Answer 13

Melatonin (at night)

Question 14

When is peak secretion of melatonin?

Answer 14

1-5yr olds

75% lower by puberty

Question 15

When is melatonin oncreaed and decreased?

Answer 15

Increase- SAD + PMS

Decrease- by phototherapy

Question 16

Where is the thymus located?

Answer 16

In mediastinum superior to the heart

Question 17

What does the thymus secrete?

Answer 17

Hormones that regulate development and later activation of T-lymphocytes

Question 18

What is the largest endocrine gland?

Answer 18

Thyroid gland

Question 19

What do follicular glands do?

Answer 19

Secrete thyroxine (T4) and Triiodothyronine (T3)
Increase rate of metabolism

Question 20

What do parafollicular cells do?

Answer 20

Secrete calcitonin

Decreases calcium and phosphate in blood

Question 21

What does the release of the parathyroid gland do to when CA+2 levels rise?

Answer 21

Increase in Ca+2
Increase in bone resorption
Decrease in urinary excretion

Question 22

What are the >25 steroid hormones synthesised from cholesterol?

Answer 22

Corticosteroids

Corticoids

Question 23

What do mineralocorticoids do?

Answer 23

Control electrolyte balance e.g aldosterone acts on kidneys to retain Na+ and excrete K+ -> maintains blood volume and pressure

Question 24

What do glucocorticoids do?

Answer 24

Secreted in response to ACTH

Question 25

What are sex steroids?

Answer 25

Weak androgens and small amounts of oestrogen

Question 26

Chromaffin cells secrete hormones of the adrenal medula. What are these two hormones?

Answer 26

Adrenaline | Noradrenaline

Question 27

What do hormones of the adrenal medulla affect and when do they rise?

Answer 27

Affect heart rate, cardiac output, blood pressure | Rises in conditions of fear, pain and other kinds of stress

Question 28

What is included in the pancreatic Islets of Langerhams?

Answer 28

``` Alpha cells Beta cells Delta cells F cells G Cells ```

Question 29

What do alpha cells release?

Answer 29

Glucagon- glycogen breakdown in liver, release of glucose to blood; stimulates fat catabolism

Question 30

What do beta cells release?

Answer 30

Insulin- synthesis of glycogen, fat and protein

Question 31

What do delta cells release?

Answer 31

Somastatin- paracrine secretion to moderate other islet cells

Question 32

What do F cells release?

Answer 32

Pancreatic polypeptide- Inhibits gall bladder contraction

Question 33

What do G cells release?

Answer 33

Gastrin- stimulates acid secretion, motility and emptying of stomach

Question 34

What do gonads in the ovaries produce and do?

Answer 34

Oestrogen and progesterone Female reproducitve system Menstrual cycle Sustaining pregnancy Preparing mammary glands for lactation

Question 35

What do gonads in the testis secrete and do?

Answer 35

Leydig cells produce testosterone Stimulates development of male reproductive system Masculine physique Sex drive Maintains sperm production

Question 36

What are the endocrine function of other organs?

Answer 36

Skin, heart, gut and placenta | Liver and kidneys

Question 37

What is the function of skin in the endocrine system?

Answer 37

Keratinocytes help produce vitamin D3

Question 38

What is the function of the heart in the endocrine system?

Answer 38

Atrial natriuretic peptide released with an increase in BP

Question 39

What is the function of stomach and small intestines in the endocrine system?

Answer 39

Coordinate digestive motility and secretion

Question 40

What is the function of the placenta in the endocrine system?

Answer 40

Secretes oestrogen, progesterone and others

Question 41

What is the function of liver in the endocrine system?

Answer 41

Converts vitamin d3 to calcidiol Secretes angiotensionogen Secretes about 15% of erythropoietin

Question 42

What is the function of kidneys in the endocrine system?

Answer 42

Converts calcidiol to calcitriol Convert angiotensinogen to angiotensin Produce 85% of erythropoietin