Endocrine System

Question 1

What is the general role of hormones?

Answer 1

-chemical messengers of the body
-act on specific target cells

Question 2

Describe the means of control and speed of response of the nervous system

Answer 2

-electrochemical impulses delivered to muscles and glands via neurons
-milliseconds

Question 3

Describe the means of control and speed of response of the endocrine system

Answer 3

hormones transported via bloodstream to most cells of the body
-seconds to days

endocrine glands produce hormones- tissue fluid- bloodstream

Question 4

Describe the structure and function of the hypothalamus

Answer 4

-sits between the cerebellum and brainstem
-houses the pituatary gland and hypothalamus

regulates:
-temp
-fluid growth
-pain and pleasure response
-hunger and thirst

Question 5

What are some of the hypothalamus hormones?

Answer 5

-corticotropin-releasing
-thyrotropin-releasing
-growth hormone-releasing
-gonadotropin-releasing
-somatonstatin-inhibts GH and TSH

Question 6

Where is the pituitary gland and what is it divided into?

Answer 6

beneath the hypothalamus
divided into:
-anterior and posterior pituitary gland

Question 7

Compare the nervous and endocrine system

Answer 7

NS- initates response rapidy
ES-initiates response slowly
NS-short duration
ES-long duration
NS-acts via AP and neurotransmitters
ES-acts at diffuse locations
NS-neurotransmitters act over a short distance
ES-hormones act over long distance

Question 8

Describe the relationship between the hypothalamus and pituatary gland

Answer 8

-at the hypoothalamus neurons sythesizing trophic hormones release them into cappilaries of the portal system

-portal vessels carry the trophic hormones directly to the anterior pituatary

-Endocrine cells releases their hormomes into second set of capilaries for distribution to the rest of the body

Question 9

Describe the function of the anterior pituitary homones

Answer 9

-growth hormone-promotes growth of bone and muscle
-prolactin-stimulates lactation
-stimulating tropic hormones

Question 10

List the stimulating trophic hormones

Answer 10

TSH- thyroid hormone
FSH-gamete
LH-sex hormone
ACTH-steroid hormones cortisol

Question 11

Describe the role of the posterior pituitary hormones

Answer 11

ADH-acts on kidneys, reduces urine output
Oxytocin-acts on uterus/breasts, uterine contractions, milk release

Question 12

What is the role of the hormones in the kidneys?

Answer 12

1,25 dihydroxyvitamin D-stimulates calcium absorption from the intestines
Renin-activates the RAS system
Erythropoietin-increases RBC production

Question 13

Describe the roles of the hormones in the testes

Answer 13

androgens,testosterone-secondary sexual characteristics, sperm production

Question 14

Whats the role of the hormones in the thymus?

Answer 14

releases thymosin and thymopoietin
-affects maturation of T lymphocytes

Question 15

Describe the role of pineal

Answer 15

-secretes melatonin
role in sleep/wake cycle, body temp, ageing and fertility

Question 16

Describe the function of the thyroid gland

Answer 16

-produces thyroid hormones and calcitonin
-takes up iodine from blood
Thyroid hormone, increases metabolic rate, heat production and regulates metabolism
calcitonon-loweres blood Ca2+

Question 17

Describe the role of the follicular cells in the thyroid

Answer 17

-excretion of triiodothyronine T3 and thyroxine T4

-increases basal metabolic rate, increases heat production, regulates metabolism of nutrients

Question 18

Describe the role of thyroid c cells

Answer 18

calcitonin
lowers blood calcium and phosphate levels

Question 19

Whats the role of the parathyroid glands?

Answer 19

-in thyroid gland
-secretes parathyroid hormone
-PTH increases blood calcium levels

Question 20

Give some examples of steroid hormones produced by adrenal glands

Answer 20

glucocorticoids
aldosterone

Question 21

list the zones of the adrenal gland and the hormones they produce

Answer 21

-zona glomerulosa-aldosterone
-zona fasciculata-glucocorticoids
-zona reticularis-adrenal sex hormone

Question 22

Whats the role of mineralocorticoids?

Answer 22

aldosterone, affects Na absorption, loss of K by kidney

Question 23

whats the role of glucocorticoids?

Answer 23

affects metabolism, regulates blood sugar levels,affects growth, anti inflammatory action, decreases the effects of stress

Question 24

Describe the role of the adrenal androgens

Answer 24

-dehydroepiandrosterone and androstenedione

converted to testosterone in periphery

Question 25

Describe the function of the adrenal medulla

Answer 25

secretes epinephrine and norepinephrine -neurotransmitter for Sympathetic system

Question 26

Describe the action of cortisol

Answer 26

-regulates metabolism and stress response -raises blood glucose -breakdown of fat anf protein -anti inflammatory actions -immune suppresion

Question 27

Describe the role of aldosterone

Answer 27

-maintains salt/water balance -acts on kidnyes to retain water regulates blood volume and BP

Question 28

describe the plasma membrane receptor second messenger system

Answer 28

-amino acid based hormones 1-hormone binds to receptor 2-receptor activates G protein 3-G protein activates adenylate cyclase, G protein becomes inactive again 4-Adenyate cyclase converts ATP to cyclic AMP 5-Cyclic AMP activates protein kinase-phosphorylation activates some of these proteins and inhibts others.

Question 29

Describe the process involved in direct gene activation of lipid soluble hormones

Answer 29

1-steroid hormone diffuses through the plasma membrane and bind to inracellular response 2- the receptor hormone complex enters the nuclei 3-the receptor hormomes complex binds a specific DNA region 4-binding initates transciption of the gene mRNA 5-the mRNA directs protein synthesis

Question 30

What are the three types of simuli causing hormone release?

Answer 30

-humoral -neural -hormonal

Question 31

Descibe the humoral stimulus and response

Answer 31

-hormone release caused by altered levels of certain critical ions and nutrients stimulus-low conc of ca2_ in the blood response-parathyroid glands screte parathyroid hormones which increase blood ca2+

Question 32

Decribe the neural stimulus and response

Answer 32

-hormone release caused by neural input stimulius-action potentials in preganglionic sympathetic fibres to adrenal muscles response-adrenal medulla cells secrete epinephrine and noraepinephrine

Question 33

Describe the hormonal stimulus and response

Answer 33

-hormone release caused by another hormone (trpic hormone) stimulus-hormones from hypothalamus response-anterior pituatary gland secretes hormones that stimulate other endocrine glands to secrete hormones

Question 34

describe up regulation and down regulation

Answer 34

up-low levels of a hormone can cause its target cells to form additional receptos for that hormone down- exposure to high hormone conc can decrease the number of receptors for that hormone

Question 35

Define permissivness

Answer 35

the situation in which one hormone can not exert its full effects without another hormones being present

Question 36

Define synergism

Answer 36

wwhen more than one hormone produces the same effects at the targer cells and their combined effects are amplified

Question 37

Describe antagonism

Answer 37

when one hormone opposes the action of another eg- insulin is antagonised by glucagon

Question 38

Describe the syntheis of thyroid hormone process

Answer 38

1-thyroglobulin is synthezied and discharged into follicule lumen 2-iodide is trapped 3-iodide is oxidised to iodine 4-iodine is attached to tyrosine 5-iodinated tyrosines and linked together to form T2 and T4 6-thyroglobulin colloid is endocytosed 7-lysosomal enzymes split T4 and T2 from thyroglobulin and the hormones diffuse from the follicular cell into the bloodstream

Question 39

define glycogenesis

Answer 39

the process of excess glucose being converted to glycogen to higher than normal, occurs in the liver

Question 40

Define glycogenolysis

Answer 40

the hydrolyisis of glycogen back to glucose in the liver. Occurs when blood glucose levels are lower than normal

Question 41

Define gluconeogenesis

Answer 41

the process of creating glucose form non carbohydrate stores in the liver. This occurs if all the glycogen has been hydrolysed into glucose and your body still needs glucose.