endocrine system

Question 1

what is the endocrine system

Answer 1

system of glands that produce hormones to enable cells to communicate in order to maintain homeostasis in the body

Question 2

what is a hormone

Answer 2

chemical messenger that enable cells to communicate

Question 3

what 3 ways does the endocrine system elicit a response

Answer 3

endocrine = secreted into bloodstream and act on distance cells

paracrine = act on nearby cells

autocrine = act on same cell

Question 4

what is autocrine

Answer 4

form of signaling in which a cell secretes a hormone or a chemical substance that binds to the receptors on the same cell, leading to functional changes in the cell

Question 5

what is paracrine

Answer 5

allows cells to communicate with each other by releasing signaling molecules that bind to and activate surrounding cells.

Question 6

what is endocrine

Answer 6

secretes into bloodstream to act on distant cells

Question 7

what is neuroendocrine

Answer 7

secreted by neurone into blood stream and act on distant cells

Question 8

what can happen when hormones lose control

Answer 8

fatigue, hair loss/excess growth, acne, weight gain etc

Question 9

what are the 3 classes of hormones

Answer 9

steroid hormones
peptide/proteins
amino acid derived

Question 10

what are steroid hormones/ process of making it

Answer 10

a group of hormones derived from cholesterol that act as chemical messengers in the body.

precursor (e.g cholesterol) then

processed to active hormone (e.g cortisol)

then secreted into blood and is transported bound to binding protein (e.g tester one)

then free active hormone is able to pass through cell membrane to exert effect

Question 11

difference between peptide and protein hormones

Answer 11

Peptide hormones consist of short chains of amino acids, whereas protein hormones are longer polypeptides

Question 12

explain the production of the peptide/protein hormones

Answer 12

• first synthesised in the RER as an inactive precursor
• further processed in Golgi and secretory vesicles
• secreted by exocytosis into circulating blood

Question 13

describe process of amino acid derived hormones

Answer 13

• tyrosine enters cell
• processed by enzymes to dopamine via precursor
• dopamine transported to secretory vesicles and converted to norepinephrine
• increased intracellular calcium levels mean secretory vesicles fuse with membrane and hormones can diffuse into bloodstream

Question 14

whats the precursor for steroid hormones

Answer 14

cholesterol

Question 15

what are 2 forms of patters for hormone release

Answer 15

episodic secretion

diurnal secretion

Question 16

what 3 types of hormones are bound to transport molecules in plasma

Answer 16

t3 t4 thyroxin-binding globulin
thyroid hormones
steroid hormones

Question 17

what are the 3 main roles of transport molecules for hormones

Answer 17

• extend biological half-life
• increase plasma conc of smaller hormones
• modulatory (alteration) effect of biological function

Question 18

if hormones are circulating in the bloodstream, why dont they affect cells all the time

Answer 18

hormone receptors must be compatible

Question 19

what are hormone receptors

Answer 19

specific shaped on cell surface or within wall allowing hormones to bind

Question 20

difference between water-soluble and lipid-soluble hormones and how they pass through cell membrane

Answer 20

water-soluble= bind to cell surface receptors and message passed via signal transduction (conversion)

lipid-soluble= pass directly through cell membrane and translocate to nucleus bound to intracellular receptor

Question 21

how do amino acid derived and peptide/protein hormones cause signalling (as they cant diffuse into the cell)

Answer 21

• they bind to the receptor on the cell
• there are intracellular receptors on the target cell which are often associated with the receptor
• this involves a G-protein
• the g-protein is next to an enzyme (adenylyl cyclase)
• this converts ATP into cyclic AMP (cAMP)
• cAMP is known as a second messenger as it signals a cascade of events that change the enzymatic activity of the cell to cause the target cell response

Question 22

give examples of some hormones that use the cAMP second messenger system

Answer 22

AHD, glucagon, ACTH

Question 23

explain how the steroid hormone causes signalling

Answer 23

• steroid hormones are lipophilic so they can freely move through the cell membrane
• they can bind to a receptor in the cell or move into the nucleus where I makes a hormone-receptor complex
• this complex causes a change in gene activity
• this increases transcription and mRNA production so increase in protein production

Question 24

give some examples of hormones that can diffuse through cell for signalling

Answer 24

testosterone, estrogen, progesterone

Question 25

what is an endocrine axes

Answer 25

series of endocrine glands that signal to each other in sequence stimulus gland A hormone A gland B hormone B gland C hormone C effect on target cells

Question 26

what is positive and negative feedback in endocrine system

Answer 26

A positive feedback loop in the endocrine system is when release of a hormone initiates actions that lead to an additional release of that hormone. Unlike a negative feedback loop, a positive one is not looking to reach homeostasis (stability). negative: If an endocrine gland senses that there is too much of one hormone in the body, it will initiate changes to decrease production of that hormone. And if there’s not enough of the hormone, the body will increase production of that hormone. You can think of it as your body’s attempt to self-regulate and self-correct.

Question 27

what is the major player in hormonal regulation (in brain)

Answer 27

hypothalamus

Question 28

what is the duty of the hypothalaus

Answer 28

- controls most of the endocrine autonomic and behavorial functions of body - controls pituitary hormone release

Question 29

what are the 2 compartments of the pituitary gland

Answer 29

anterior and posterior pituitary gland

Question 30

what is the function of the anterior pituitary gland

Answer 30

- controls activity of other endocrine glands - controls growth - stimulates production of oestrogen and progesterone - ovulation and pregnancy - testorone production and spermatogenesis

Question 31

what is the function of the posterior pituitary gland

Answer 31

store and releases two hormones: oxytocin and antidiuretic hormone (ADH, or vasopressin)

Question 32

what the difference between primary and secondary endocrine disorders

Answer 32

primary= originating in peripheral of endocrine gland itself secondary= under/overstimulating by tropic gland

Question 33

what is a product of excess thyroid

Answer 33

hyperthyroidism a swelling in your neck caused by an enlarged thyroid gland (goitre) an irregular and/or unusually fast heart rate (palpitations) twitching or trembling. warm skin and excessive sweating. red palms of your hands. loose nails. a raised, itchy rash – known as hives (urticaria) patchy hair loss or thinning.

Question 34

product of thyroid deficiency

Answer 34

tiredness. weight gain. depression. being sensitive to the cold. dry skin and hair. muscle aches.