Physiology Flashcards Preview

2MB Endocrinology > Physiology > Flashcards

Flashcards in Physiology Deck (45)
Loading flashcards...
1
Q

The endocrine system involves ducts. True/False?

A

False

It is a ductless system involving glands that secrete directly into blood

2
Q

How is specificity of signalling by endocrine glands achieved?

A

Chemically distinct hormones
Specific hormone receptors
Distinct distribution of receptors

3
Q

List the main endocrine glands of the body

A
Hypothalamus
Pituitary
Parathyroid
Thyroid
Adrenal gland
Pancreas
Placenta
Ovaries/testes
4
Q

What is meant by an autocrine gland?

A

Hormone released acts back on the structure that released it

5
Q

What is meant by a paracrine gland?

A

Hormone released acts on neighbouring structures

6
Q

List the 3 main classes of hormones

A

Glycoproteins + peptides
Steroids
Tyrosine derivatives

7
Q

Give an example of glycoprotein/peptide hormones

A

Insulin
Growth hormone
Oxytocin
Prolactin

8
Q

Give an example of a steroid hormone

A

Cortisol

Testosterone

9
Q

Give an example of a tyrosine-derivative hormone

A

Adrenaline
Thyroid hormone
Melatonin

10
Q

A whole protein is always required to achieve hormonal effect. True/False?

A

False

Protein can be cleaved into active hormonal units

11
Q

On a basic level, how are amines, peptides and proteins released from the endocrine cell?

A

Synthesised, packaged into vesicles and then released in response to stimuli via exocytosis

12
Q

On a basic level, how are steroid hormones released from the endocrine cell?

A

Synthesised upon demand, then stimuli increases cellular uptake and availability of cholesterol + rate of conversion into pregnenolone, which is then used to build steroid to be released

13
Q

Steroid hormones travel freely in blood. True/False?

A

False

Usually has carrier protein in inactive form

14
Q

Which carrier protein binds cortisol?

A

Cortisol-binding protein! FANCY THAT

15
Q

Which carrier protein binds thyroxine (T4)?

A

Thyroxine-binding globulin

16
Q

Which hormones normally bind to sex steroid-binding globulin?

A

Testosterone

Estradiol

17
Q

Free and bound lipophilic hormone are in equilibrium in the blood. True/False?

A

True

18
Q

What does “tropic” mean with regards to hormones?

A

Refers to a hormone that acts upon another endocrine gland to regulation secretion of hormone

19
Q

What are the biggest players in elimination of hormone?

A

Liver

Kidney

20
Q

Time taken to reach half life of amine hormones is achieved in seconds/minutes/hours

A

Seconds

21
Q

Time taken to reach half life of protein hormones is achieved in seconds/minutes/hours

A

Minutes

22
Q

Time taken to reach half life of steroid hormones is achieved in seconds/minutes/hours

A

Hours

23
Q

List the 3 main distinct types of hormone receptor

A

GPCR
Receptor kinases
Nuclear receptors

24
Q

Which of the 3 main types of hormone receptor are cell surface receptors?

A

GPCR

Receptor kinases

25
Q

Which of the 3 main types of hormone receptor are intracellular receptors?

A

Nuclear kinases

26
Q

Describe class 1 nuclear receptors

A

Activate by steroid hormones

Usually in cytoplasm bound to heat-shock-proteins

27
Q

Describe class 2 nuclear receptors

A

Activate by lipids

Present in nucleus

28
Q

Describe the hybrid class of nuclear receptors

A
Activated by T3
Similar function to class 1
29
Q

Give an example of a hormone that utilises signalling via receptor kinases

A

Insulin

30
Q

What are the 3 main components of the hypothalamic pituitary axis?

A

HYPOTHALAMUS influences PITUITARY to secrete hormones to act on PERIPHERAL GLAND (thyroid, adrenal etc.)

31
Q

List the main hormones secreted by the anterior pituitary

A
GH
LH/FSH
ACTH
TSH
Prolactin
32
Q

List the main hormones secreted by the posterior pituitary

A

ADH

Oxytocin

33
Q

What is the effect of peripheral hormones secreted by target glands (thyroid, adrenals etc.) upon the pituitary and hypothalamus?

A

Negative feedback loop (inhibition)

34
Q

List the factors that influence our ability to measure hormone levels

A
Pattern of secretion
Presence of carrier proteins
Interfering agents
Stability/half-life
Absolute concn
35
Q

What is the major determination of hormone concentration?

A

Rate of secretion

36
Q

Outline the thyroid hormone axis

A

Hypothalamus secretes TRH which stimulates anterior pituitary to stimulate TSH which stimulates thyroid to produce thyroid hormones

37
Q

Thyroid hormones inhibit the thyroid, anterior pituitary and hypothalamus to reduce further thyroid hormone release. True/False?

A

False

They do not inhibit the thyroid gland!

38
Q

What test is done to evaluate thyroid hormone?

A

Highly-sensitive TSH assay

39
Q

Outline the hypothalamic-pituitary-adrenal axis (HPA axis)

A

HYPOTHALAMUS releases CRH to stimulate ANTERIOR PITUITARY to release ACTH which stimulates ADRENALS to release cortisol

40
Q

Which parts of the HPA axis does cortisol inhibit via negative feedback loop?

A

Anterior pituitary

Hypothalamus

41
Q

Random cortisol measurement is useful in determining cortisol levels. True/False?

A

False

Circadian rhythm means levels will vary widely throughout the day

42
Q

GH stimulates the liver to produce what hormone?

A

IGF-1

43
Q

Which cells secrete prolactin?

A

Lactotroph cells in the anterior pituitary

44
Q

Which hypothalamic hormone inhibits release of prolactin?

A

Dopamine

45
Q

What is the rate-limiting step in steroid hormone metabolism?

A

Cholesterol to pregnenolone