Endocrine System SEM1

Question 1

How do hormones travel to get to target cells

Answer 1

Hormones travel via bloodstream

Question 2

What are neuroendocrine hormones

Answer 2

Neural cells that release chemical signals into the bloodstream

Question 3

Where are releasing hormones released from and what do they act on

Answer 3

Released from hypothalamus and act on the pituitary gland

Question 4

Where are stimulating hormones released from and what do they act on

Answer 4

From pituitary to act on another endocrine gland

Question 5

Where are non-tropic hormones released from

Answer 5

From endocrine gland to the target cells

Question 6

What does the hypothalamus release

Answer 6

Thyrotropin releasing hormone (TRH)

Question 7

What does the anterior pituitary release

Answer 7

Thyroid stimulating hormone (TSH)

Question 8

What does the thyroid release

Answer 8

Thyroid hormone (T3 and T4)

Question 9

Where are amino hormones derived from

Answer 9

Derived from tyrosine

Question 10

What hormones are encoded in genes

Answer 10

Peptide and protein hormones

Question 11

Where are steroid hormones derived from

Answer 11

Derived from cholesterol

Question 12

What are properties of protein and polypeptide hormones

Answer 12

Stored in secretory granules and released on stimulation
Ca++ dependent event - exocytosis
Hydrophilic - cannot freely cross membranes

Question 13

What are properties of steroid hormones

Answer 13

Steroids are lipophilic molecules that freely cross membranes
Steroids are not stored but released as made
Travel in blood

Question 14

What changes can second messengers create

Answer 14

Phenotypic changes in target cell

Question 15

What are the phenotypic changes second messengers create in target cells

Answer 15

Alter phosphorylation of proteins
Alter permeability of membranes

Question 16

What does hormone binding receptors being internalised result in

Answer 16

Results in reduced responsiveness of target cell and receptor may be recycled to cell surface or degraded

Question 17

What are intracellular receptors

Answer 17

Steroid and thyroid hormones and act via intracellular receptors

Question 18

How does the hormone-receptor (HR) complex interact with DNA

Answer 18

Interacts directly with DNA in chromatin fibre at the promoter of specific genes

Question 19

How does the hormone-receptor (H-R) complex act

Answer 19

Acts as a transcription factor to enhance (or decrease) rate of transcription

Question 20

What do the physiological effects of hormones depend on

Answer 20

Depend on their concentration in blood and extracellular fluid

Question 21

What are the three factors which determine the concentration of hormones as seen by the target cells

Answer 21

Rate of production
Rate of delivery
Rate of degradation and elimination

Question 22

What can cause for abnormal production or function of hormones

Answer 22

Genetic diseases
Autoimmune diseases
Gene mutations

Question 23

What does the anterior pituitary gland secrete

Answer 23

Secretes trophic hormones that influence activity of target glands and tissue

Question 24

Where is the thyroid located

Answer 24

Anterior to the trachea
Inferior to the larynx

Question 25

How are Tri-iodothryonine (T3) and thyroxine (T4) synthesised

Answer 25

Synthesised by follicular cells by iodination of throsine

Question 26

How are Tri-iodothryonine (T3) and thyroxine (T4) stored

Answer 26

Stored extracellularly in follicular colloid on surface of thyroglobulin molecules

Question 27

What are the actions of thyroid hormones

Answer 27

Metabolic effects Physiological effects Reproductive effects Developmental effects Cellular effects

Question 28

What are the metabolic effects of thyroid hormones

Answer 28

Heat production Glucose production Protein synthesis Lipid metabolism

Question 29

What are the physiological effects of thyroid hormones

Answer 29

Stimulation of heart rate Mental activity Red blood cell production Appetite Gut motility

Question 30

What are the reproductive effects of thyroid hormones

Answer 30

Female fertility Maintenance of milk secretion Onset of puberty

Question 31

What are the developmental effects of thyroid hormones

Answer 31

Normal brain development

Question 32

What are the cellular effects of thyroid hormones

Answer 32

RNA synthesis Na+/K+ dependent ATPase activity Amino acid transport into responsive cells

Question 33

How does hypothyroidism occur

Answer 33

Lack of thyroid hormones either because of the thyroid (primary) or from lack of stimulation by TSH (secondary)

Question 34

How does hyperthyroidism occur

Answer 34

Over activity of the gland

Question 35

What does the posterior pituitary gland secrete

Answer 35

Secretes oxytocin and vasopressin

Question 36

What is the role of osmoreceptors

Answer 36

Send signals to the neuroendocrine cell in the hypothalamus that make vasopressin when plasma osmolality exceeds the threshold => increase vasopressin secretion

Question 37

What factors can cause the stimulation of vasopressin secretion

Answer 37

High osmolality Low blood volume Low blood pressure Angiotensin Nicotine Nausea

Question 38

What factors can cause the inhibition of vasopressin secretion

Answer 38

Low osmolality High blood volume High blood pressure Atrial natriuretic peptide Alcohol

Question 39

What is diabetes insipidus

Answer 39

Inability to secrete or respond to vasopressin

Question 40

What does it mean to be nephrogenic

Answer 40

Kidneys do not respond to ADH

Question 41

What is the role of oxytocin

Answer 41

Stimulates contraction of myopithelial cells in mammary glands to cause milk ejection

Question 42

What is endocrine tissue called

Answer 42

Pancreatic islets or islets of langerhans

Question 43

What are the secratory cells of the pineal gland called and what does the gland secrete

Answer 43

Secretory cells = pinealocytes Releases melatonin