Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

GSSE Physiology > Endocrine Physiology > Flashcards

Endocrine Physiology Flashcards

1
Q

What are some examples of steroid binding proteins? What are their 3 main functions

A

sex hormone binding globulin: glycoprotein that binds to sex hormones, testosterone and 17 beta-estradiol

transcortin binds to progesterone, cortisol, and other corticosteroids

  1. Increase solubility of lipid based hormones in blood
  2. Reduce rate of hormone loss in urine by preventing filtration
  3. Act as a source of hormone reservoir as equilibrium changes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Describe the neural and vascular connections between the hypothalamus and the pituitary?

A

VASCULAR connection between hypothalamus and ANTERIOR pituitary via the portal hypophysial vessels

NEURAL connection between hypothalamus and POSTERIOR pituitary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the afferent stimulus for vasopressin and where is its integrating area?

A

from osmoreceptors in the hypothalamus

integrated in supraoptic and paraventricular nuciel

Ganong 17-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the afferent stimulus for thyroid stimulating hormone (via TRH) and where is the integrating area in the hypothalamus?

A

temperature receptors

Integrated in paraventricular nuclei and neighboring areas
Ganong 17-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Which hormones are secreted by the anterior pituitary? (6)

Which are secreted by the posterior pituitary? (2)

A 
Beta-lipiotrophyin - ???
ACTH - adrenal cortex
Growht hormone - somateomedins
TSH - thyroxine
FSH - Estrogen
LH - progesterone/estrogen
Prolactin - breast

Vasopressin/oxytocin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the hypophysiotrophic hormones and what do they act upon? (7)

A

Corticotrophin releasing hormone: stimulates b-LPH and ACTH
Thyrotropin releasing hormone: stimulates TSH
Growth hormone releasing hormone + Growth hormone inhibiting hormone: self explanatory
Luteinising hormone releasing hormone: self explanatory
Gonadotrophin releasing hormone: stimulates LH and FSH
Prolactin inhibiting hormone : self explanatory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the 2 main functions of the thyroid gland?

A

Secrete hormone responsible for metabolism in tissues

Secrete calcitonin to regulate circulating levels of calcium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which between t3 and t4 are

  • secreted in greater volume
  • has greater biologic activity
  • is primarily responsible for feedback of TSH secretion
A

T4 in greater volume
T3 greater biologic activity
T3 responsible for feedback

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the processing of iodide and how it is metabolised in the thyroid?

A

Ganong’s figure 19-5 19-6 p 339

  • dietary iodide absorbed in intestine
  • thyrocytes use Na/I symporter (basolateral membrane) to pump in iodide (Na pumped out with Na/K atpase)
  • iodide exits apical membrane via pendrin (Cl/I exchanger) to colloid where thyroid hormone synthesis occurs
  • iodide oxidized to iodine and incorporated into tyrosine residues by thyroid peroxidase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What happens to thyroid binding proteins under the following circumstances?

  • hyperthyroidism
  • Hypothyroidism
  • Estrogens/methadone/heroin/antipsychotics
  • Glucocorticoids/androgens/asparaginase
A
  • normal
  • normal
  • high
  • low
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are deiodinases, where are they located and what do they do?

What can suppress their activity?

A

Enzymes that metabolise T4 and T3

Located in Liver/ kidneys, brain, thyroid, pituitary

Maintain formation of T3 from T4 in periphery or maintain ratios in particular tissues

Suppressed by burns/trauma/advanced cancer/cirrhosis/CKD/ MI/febrile states

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are some states that decrease thyroid hormone secretion?

A

stress
dopamine
somatostatin
glucocorticoids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the effects of thyroid hormone on the

  • heart
  • adipose tissue
  • muscle
  • bone
  • nervous system
  • gut
  • lipoprotein
  • metabolically active tissues
A
  • heart : chronotropism and ionotropism by increasing beta adrenergic receptors and increase proportio of alpha-mosin heavy chain
  • adipose tissue: stimulates lipolysis
  • muscle: increased catabolism
  • bone: promotes normal growth
  • nervous system: promotes development
  • gut: increased rate of carb absorption
  • lipoprotein: formation of LDL receptors
  • metabolically active tissues: stimulates oxygen consumption, increased BMR
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the main actions of parathyroid hormone?

A
  • increase urinary phosphate excretion by decreasing reabsorption
  • directly on bone to increase bone resorption and mobilise Ca2+
  • increases the reabsorption of Ca2+ in the distal tubules
  • increases the formation of 1,25-dihydroxycholecalciferol, and this ↑Ca2+ absorption from the intestine
  • long term, PTH stimulates both osteoblasts and osteoclasts

Fig 21-3 p 379 Ganong’s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the primary actions of 1,25-VitD2OH?

A

To increase calcium absorption from the intestine

  • with increasing Ca2+ serum levels, 1,25 dihydroxycholecalciferol levels fall
  • acts directly on the parathyroid gland to ↓preproPTH mRNA
  • acts to increase expression of calcium absorption channels in proximal tubules
  • increases expression of calbindin-D
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the primary action of calcitonin?

A
  • To lower serum calcium/phosphate
  • inhibit bone resorption (inhibits osteoclasts)
  • increases calcium excretion in urine
17
Q

Where is calcium absorbed?

How much of it is filtered in kidneys vs reabsorbed?

A

Transported across brush border of intestinal epithelial cells
Binds to intracellular protein calbindinD9K to prevent disturbance of intracellular signalling

Filtered in kidneys, 98% reabsorbed (60% in proximal tubules, remainder in ascending LoH and distal tubule)

18
Q

What are the two different cell types of the parathyroid gland and what are their actions?

A

Chief cells – more abundant, synthesise and secrete PTH

Oxyphil cells – less abundant, unknown function

19
Q

Why is there increased calcium in urine in hyperparathyroidism?

A

PTH acts to increase reabsorption of calcium in distal tubules
Ca2+ excretion in urine is usually ↑ in
hyperparathyroidism because there is an increased load of filtered calcium that overwhelms reabsorption

20
Q

What physiological states stimulate (5) vs inhibit (3) secretion of PTH?

A 
- PTH secretion is stimulated by
o ↓plasma Ca2+
o ↓magnesium
o β-adrenergic discharge
o ↑phosphate (indirectly by lowering Ca2+) 
o Chronic renal disease
  • PTH secretion is inhibited by
    o ↑plasma Ca2+
    o ↑magnesium and severe Mg deficiency
    o Calcitriol
21
Q

What is the key mechanism for hypecalcaemia of malignancy?

A

p 382 Ganong’s
80% of patients have hypercalcaemia due to parathyroid hormone-related protein
Similar morphology to PTH
Usually found in keratinocytes, smooth muscle and teeth, but hyper-secreted in cancers of breast, kidney, ovary and skin.

22
Q

What’s the difference between lipoprotein lipase and hormone sensitive lipase?

A

lipoprotein lipase: makes more triglycerides available from VLDLs to reform fatty acids and fats in cells

hormone sensitive lipase: causes lipolysis eg. in fasting

23
Q

What are the actions of insulin in different tissues?

  • Adipose
  • Muscle
  • Liver
A

Adipose tissue = ↑glucose entry, ↑FFA synthesis, ↑triglyceride deposition, ↑lipoprotein lipase, ↑K+ uptake

Muscle = ↑glucose entry, ↑glycogen synthesis, ↑AA uptake, ↑protein synthesis, ↓protein catabolism, ↑K+ uptake

Liver = ↓ketogenesis, ↑protein synthesis, ↑lipid synthesis, ↓gluconeogenesis, ↑glycogen synthesis
General = ↑cell growth
24
Q

What are the 3 layers of the adrenal cortex and what do they produce?

A
  1. zona glomerulosa secrete aldosterone (mineralocorticoid)
  2. zona fasciculata secrete cortisol (glucocorticoids)
  3. zona reticularis secrete androgens

Go Fetch Rex
deeper you go, sweeter it gets

See fig 20-2 cortisol and androgens from both fascitulata and reticularis

25
Q

What are the 2 effects of ACTH on the adrenal cortex?

A
  • trophic effect on adrenal cortex
  • acts on cells in zona fasciculata & reticularis –> (+) G protein –> increase intracellular cAMP –> convert cholesterol to cortisol
26
Q 
7 FACTS ABOUT THE PINEAL GLAND
- where is it in relation to blood brain barrier
- what does it secrete
- when is it more active
- what neural modulation does it have
- where is this neural modulation
and more!
A
  1. is outside of the blood brain barrier
  2. secretes melatonin: made from tryptophan via serotonin so contains both serotonin and melatonin
  3. periodic pattern secretion: higher during night and low during day
  4. postganglionic fibers which release NA mediate this cylic behaviour
  5. synchrony is ultimately controlled by suprachiasmatic nuclei in hypothalamus
  6. NA from postganglionic fibers (+) cAMP synthesis and hence melatonin synthesis and secretion
  7. has no influence over K+ metabolism
27
Q

What are the key hormonal changes during the follicular phase of the menstrual cycle?

What are the key events?

A 
FSH ++ and LH +  secretion 
oestrogen from theca ++
\+ve feedback to increase FSH receptors 
FSH + oestrogen increase LH receptors 
LH + +ve feedback loop

rapid proliferation of granulossa cells
theca produced: secretes oestrogen/progesterone, + highly vascular capsule
by 6th day, dominant follicle arises
on 14th day, follicle ruptures

28
Q

What are the key events during the ovulation phase of the menstrual cycle?

A

14th day, follicle rupture
granulosa and theca cells proliferate
bleeding from follicle clots
clot replaced by corpus luteum

29
Q

What are the key events during the luteal phase of the menstrual cycle?

A

luteal cells secrete estrogen + progesterone which supress FSL/LH
if pregnancy does not occur, corpus luteum degenerates by day 24
when corpus luteum regresses, hormonal support for endometrium withdraws and necrosis, spasm and degeneration of the walls of the arteries take place, producing menstrual flow

p 401 Ganong’s

30
Q

What is the role of HCG in pregnancy?

A
  • prevents the endometrium from sloughing away
  • prevents involution of corpus luteum
  • exerts an interstitial cell-stimulating effect on the testes of the male foetus resulting in testosterone production in male fetuses
31
Q

What are the functions of oestrogen during pregnancy?

A
  • Enlargement of uterus
  • Enlargement of breasts and growth of the breast ductal structure
  • Enlargement of female external genitalia
  • relaxing pelvic ligaments
32
Q

What are the functions of progesterone in pregnancy?

A
  • Causes decidual cells to develop in the uterine endometrium (nutrition for the embryo)
  • ↓contractility of the pregnant uterus
  • ↑secretion of fallopian tubes and uterus to provide appropriate nutrition
  • Helps oestrogen prepare the breast for lactation
33
Q

What are the functions of LH and FSH in males?

A

FSH
• (+) seminiferous tubules to make sperm
• (+) sertoli cells to control maturation of spermatids to spermatozoa
• (+) production of inhibin, acts as a negative feedback on pituitary to (-) FSH
release

LH
• Is trophic on the interstitial Leydig cells, stimulating androgen production

34
Q

What are some key changes in pregnancy physiology

  • anterior pituitary
  • thyroid
  • parathyroid
  • uterus
  • circulation
  • respiration
  • urinary
  • immunology
A
  • Ant pituitary 50% increase in size, increased secretion of CTH, TH, and prolactin
  • Increase glucocorticoid secretion and aldosterone secretion
  • 50% increase in size and production of thyroxine
  • enlarged PT gland and increased PTH
  • Ovaries and placenta produce estorgens, progesterone and relaxin
  • uterus, breasts, vagina and introitus enlarge
  • 15% increased in BMR
  • CO increase by 27th weak, normal in final 8 weeks
  • blood volume increases by 30%
  • minute ventilation increases, RR increases
  • urine production increase
  • decrease maternal antibody production
35
Q

What are the key physiological differences between adrenaline and noradrenaline?

A

Noradrenaline

  • vasoconstriction
  • reflex bradycardia
  • decreased cardiac ouptut
  • decreased pulse pressure
  • more receptors of alpha receptors

Adrenaline (10%, methylated Norad)

  • HR and CO increases
  • TPR and DBP decrease
  • increased pulse pressure
  • increase cardiac output
  • more stimulation of beta receptors
36
Q

What are some of the physiological states that trigger renin? (4)

A

stimulated by ↓ECF, ↓BP, ↑SNS output (catecholamines) and prostaglandins

37
Q

What mechanisms trigger thirst?

A

Hypovolaemia: via baroreceptors and angiotensin II

Hypertonicity: via osmoreceptors

collated in subfornical area of hypothalamus to trigger thirst

modulated by social/emotional triggers

GSSE Physiology (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions