Homonal communication - 5.4

Question 1

What is the endocrine system?

Answer 1

A communication system using hormones as signalling molecules.

Question 2

What are hormones?

Answer 2

Molecules that are either proteins or steroids which are released by endocrine glands into the blood. They act as messengers, carrying a signal from the gland to the target organ/tissue.

Question 3

What examples of non-steroid hormones (protein/peptide)

Answer 3

Adrenaline, insulin, glucagon, thyroxine, insulin

Question 4

Name three examples of a steroid hormone

Answer 4

oestrogen, testosterone, aldosterone, cortisol

Question 5

What are endocrine glands?

Answer 5

Glands which secrete hormones into the blood

Question 6

What are exocrine glands?

Answer 6

Glands which secrete their products into a duct

Question 7

Name three examples of endocrine glands

Answer 7

Pituitary, adrenal, pancreas, (thyroid, ovaries, testes)

Question 8

Name 3 examples of exocrine glands.

Answer 8

Salivary, liver, pancreas, (stomach)

Question 9

What is a target cell of a hormone?

Answer 9

A cell in which the hormone causes an effect.

Question 10

What do target cells of non-steroid hormones need to accept the signal?

Answer 10

Complementary receptors on their cell surface membrane.

Question 11

What is a first messenger?

Answer 11

A non-steroid hormone.

Question 12

What is a second messenger?

Answer 12

A signalling molecule released by the first messenger that stimulates a change in a cell.

Question 13

Name an example of a second messenger?

Answer 13

cAMP

Question 14

What type of gland is the adrenal gland?

Answer 14

Endocrine

Question 15

What are the two regions of the adrenal gland?

Answer 15

1) Adrenal Cortex

2) Adrenal Medulla

Question 16

What are the three parts of the adrenal cortex?

Answer 16

1) Zona glomerulosa
2) Zona fasciculata
3) Zona Reticularis

Question 17

What type of hormones does the zona glomerulosa secrete?

Answer 17

Mineralocorticoids

Question 18

Name an example of a mineralocorticoid

Answer 18

Aldosterone

Question 19

What is the function of mineralocorticoids?

Answer 19

They help control concentrations of sodium and potassium.

As a result they maintain blood pressure.

Aldosterone acts on the distal tubules and collecting ducts in the kidney to increase water retention.

Question 20

What type of hormones does the zona fasciculata secrete?

Answer 20

Glucocorticoids

Question 21

Name an example of a glucocorticoid

Answer 21

Cortisol

Question 22

What is the function of glucocorticoids?

Answer 22

Help control metabolism of carbohydrates, fats and proteins in the liver.

Cortisol stimulates the production of glucose in the liver

Question 23

What does the zona reticularis secrete?

Answer 23

Sex hormone precursors

Question 24

What type of hormone is adrenaline?

Answer 24

Non-steroid

Question 25

Why cant adrenalin enter a cell like a steroid hormone?

Answer 25

It is polar

Question 26

What are the three target cells of adrenalin?

Answer 26

Smooth muscle, cardiac muscle, hepatocyte

Question 27

Name 7 affects of adrenalin on the body

Answer 27

1) Increased tidal volume 2) increased stroke volume 3) increased heart rate 4) vasoconstriction 5) pupil dilation 6) piloerection 7) inhibition of digestion

Question 28

Why is the adrenal cortex well supplied with blood?

Answer 28

To enable hormones to be efficiently transported into the blood stream

Question 29

Where in the adrenal gland is adrenalin secreted from?

Answer 29

Adrenal medulla

Question 30

What are the two different functions of the pancreas?

Answer 30

Exocrine -Secrete digestive juices Endocrine -Secrete hormones to control blood sugar levels

Question 31

What are acini? What is their function?

Answer 31

Cells in the pancreas which group together to secrete digestive juices. The digestive juices - aid intake of nutrients from the small intestine into the blood via specific enzymes - neutralise the stomach acid that has entered the small intestine via sodium hydrogen carbonate

Question 32

What enzymes are contained within the digestive juices secreted by the acini?

Answer 32

1) Pancreatic amylase - a carbohydrase which digests amylose (long polysaccharide) to maltose (disaccharide) 2) Trypsinogen - an inactive protease (break down proteins) which will be converted to the active form trypsin when it enters the upper small intestine 3) Lipase - digests lipid molecules

Question 33

Where does the endocrine and exocrine functions of the pancreas occur?

Answer 33

Endocrine -Acini Exocrine -Islet of Langerhans (beta/alpha)

Question 34

What is the function of the islet of Langerhans?

Answer 34

Alpha cells - secrete glucagon Beta cells - Insulin

Question 35

What does glucagon and insulin do?

Answer 35

Glucagon -causes the release of glycogen into blood glucose Insulin -causes blood glucose to be sored as glycogen in the liver