Intro To The Endocrine System + Endocrine Control Of Appetite

Question 1

What is homeostasis?

Answer 1

It is the maintenance of a dynamic equilibrium of conditions to maintain a stable internal environment in the body

Question 2

What is a homeostatic mechanism?

Answer 2

Mechanisms which counteract changes in the internal environment

Question 3

What are the 3 key characteristics of a control system?

Answer 3

Receptor detects stimulus
Control centre determines set point and determines response
Effector enacts response

Question 4

Give 4 types of receptor:

Answer 4

Chemoreceptors (chemicals)
Thermoreceptors (temperature)
Proprioceptors (position)
Nociceptors (pain)

Question 5

What is an important feature of the biological rhythms of the body?

Answer 5

The set point of the control centre is not fixed, it can vary

Question 6

What is the biological clock in the brain called?

Answer 6

Suprachiasmatic nucleus (small group of neurones in brain)

Question 7

How is jet lag caused?

Answer 7

Mismatch between environmental cause and body clock

Question 8

What hormone is responsible for setting the biological clock (Circadian rhythm) in the body?

Answer 8

Melatonin

Question 9

What gland produces melatonin?

Answer 9

Pineal gland

Question 10

What is negative feedback?

Answer 10

Response in a way to reverse the direction of change

Question 11

What is positive feedback?

Answer 11

Response which changes the variable even more in the direction of change

Stimulus is enhanced

Question 12

What % of a man’s body mass is water?

Answer 12

60%

Question 13

What is the amount of water which the average 70kg man has?

Answer 13

42L

Question 14

How much of the 42L of water in the average 70kg man is Intracellular?

Answer 14

28L

Question 15

How much of the 42L of water in the average 70kg man is extracellular?

Answer 15

14L

Question 16

How much of the 14L of extracellular water in the average 70kg man is interstitial fluid?

Answer 16

11L

Question 17

How much of the 14L of extracellular water is blood plasma in the average 70kg man?

Answer 17

3L

Question 18

How many litres of blood are there in the average 70kg man?

Answer 18

5L
3L Blood plasma
2L of blood cells

Question 19

What is an Osmole?

Answer 19

The amount of a substance that dissociates in solution to form one mole of osmotically active particles

Question 20

What is osmolarity?

Answer 20

The number of osmoses per LITRE of solution

Question 21

What is Osmolality?

Answer 21

The number of osmoles per Kg of solution

Question 22

What is the difference between Osmolarity and Osmolality?

Answer 22

Osmolarity concerns LITRES of solution
Osmolality concerns KG of solution

Question 23

What hormone is essential in water/fluid homeostasis?

Answer 23

ADH (Antidiuretic hormone)

Question 24

What affect does ADH have on the body?

Answer 24

Increases water reabsorption in the kidney so less water is lost from the body.

Increases number of aquaporins in the Distal Convoluted Tubule and collecting duct of the kidneys nephrons

Question 25

When is ADH released?

Answer 25

When osmoreceptors in the hypothalamus detect the blood has a HIGH Osmolality

Question 26

Where is ADH produced? Where is ADH stored and secreted from?

Answer 26

Hypothalamus Posterior pituitary

Question 27

What hormones regulate plasma glucose homeostasis?

Answer 27

Insulin Glucagon

Question 28

What should the concentration of plasmas glucose be?

Answer 28

5mmol/L

Question 29

What is the definition of a hormone?

Answer 29

They are chemical signal produced in endocrine glands or tissues that travel in the bloodstream to cause own effect on other tissues

Question 30

What other organs and tissues release hormones that aren’t glands?

Answer 30

Heart Liver Stomach Placenta Adipose Kidney

Question 31

What important hormones does the heart produce?

Answer 31

ANP and BNP Regulate BP

Question 32

What important hormone does the Liver produce?

Answer 32

IGF1

Question 33

What important hormones does the stomach produce?

Answer 33

Gastrin and Ghrelin

Question 34

What important hormones does the placenta produce?

Answer 34

Inhibit, placental lactogen

Question 35

What important hormone does Adipose produce?

Answer 35

Leptin

Question 36

What important hormones does the Kidney produce?

Answer 36

Erythropoietin, Renin, calcitriol

Question 37

What are the 4 methods of hormone communication?

Answer 37

Autocrine Paracrine Endocrine Neurocrine

Question 38

What is Autocrine hormonal communication?

Answer 38

Hormone signal acts back on the cell of origin

Question 39

What is Paracrine hormonal communication?

Answer 39

Hormone carried to adjacent cells not in the blood

Question 40

What is Endocrine hormonal communication?

Answer 40

Hormone is secreted into the blood and transported to a remote site/distant target

Question 41

What is Neurocrine hormonal communication?

Answer 41

Hormone originates in a neurone, it is released into the bloodstream after travelling down the axon of the neurone a distant target

Question 42

What is the difference between the endocrine system and the nervous system?

Answer 42

Signal: Hormones V Neurotransmitters + action potentials Nature: Chemical V Chemical and electrical Conveyance: Bloodstream V Synapses + Axons Mediators: Receptors V Receptors Speed: Slow V Fast

Question 43

What are the 4 classifications of hormone?

Answer 43

Peptide/Polypeptide Amino acid derivatives (Amines) Glycoproteins Steroids

Question 44

Which 2 classifications of hormone are all water soluble?

Answer 44

Peptide Glycoprotein

Question 45

Which classification of hormone is only lipid soluble?

Answer 45

Steroids

Question 46

Which classification of hormone can be both water soluble or lipid soluble?

Answer 46

Amino acid derivatives (Amines)

Question 47

Give 3 examples of peptide hormones

Answer 47

Insulin Glucagon Growth hormone

Question 48

Give 3 examples of glycoprotein hormones

Answer 48

LH FSH TSH

Question 49

Give 3 examples of amino acid derived hormones

Answer 49

Adrenaline Noradrenaline Thyroid hormones

Question 50

Give 3 examples of steroid hormones

Answer 50

Cortisol Aldosterone Testosterone

Question 51

What precursor are steroid hormones all synthesised from?

Answer 51

Cholesterol

Question 52

If a hormone is not water soluble (is lipid soluble) how is it transported in the blood?

Answer 52

Bound to carrier proteins

Question 53

Which of the 2 is biologically active? The free form of the hormone or the bound hormone?

Answer 53

Free hormone is biologically active

Question 54

What 3 factors determine hormone levels in the blood?

Answer 54

Rate of production Rate of delivery Rate of degradation

Question 55

How do water soluble hormones exert their actions on a cell?

Answer 55

Bind to cell surface receptors: -G protein coupled receptors -tyrosin kinase receptors

Question 56

How do lipid soluble hormones exert their affects on a cell?

Answer 56

Bind to Intracellular receptors (on DNA in nucleus)

Question 57

Which hormones act faster and why? Water soluble or lipid soluble?

Answer 57

Water soluble since they bind to receptors on the cell surface membrane

Question 58

When does somebody gain body weight?

Answer 58

When energy intake exceeds energy expenditure

Question 59

What is the cluster of neurones in the brain called that control appetite?

Answer 59

Arcuate nucleus

Question 60

Where is the arcuate nucleus located in the brain?

Answer 60

Hypothalamus

Question 61

What are the 2 types of neurone found in the arcuate nucleus?

Answer 61

Stimulatory Inhibitory

Question 62

What do stimulatory neurones in the arcuate nucleus do and how do they do this?

Answer 62

Promote hunger Contain NPY (Neuropeptide Y) and AgRP (Agouti-related peptide)

Question 63

What do inhibitory neurones in the arcuate nucleus do and how do they do this?

Answer 63

Promote satiety Contain POMC which makes alpha MSH and Beta endorphin

Question 64

What does ghrelin do and where is it produced?

Answer 64

Simulates appetite Produced in stomach when stomach is empty

Question 65

What type of hormone is ghrelin?

Answer 65

Peptide

Question 66

What does PYY (Peptide tyrosine tyrosine) do and where is it produced?

Answer 66

Suppresses appetite Made by ileum and colon

Question 67

What does leptin do and where is it produced?

Answer 67

Suppresses appetite Released by adipocytes

Question 68

How does leptin suppress appetite?

Answer 68

Simulates inhibitory neurones Inhibits excitatory neurones Induces expression of uncoupling proteins in mitochondria

Question 69

What does insulin do?

Answer 69

Suppress appetite

Question 70

What does amylin do and where is it produced?

Answer 70

Suppresses appetite Beta cells of oancreas