Brainscape's Knowledge GenomeTM

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


See full index

Endocrine System > Endocrine Physiology > Flashcards

Endocrine Physiology Flashcards

1
Q

What is the endocrine system?

A

A system that controls function via the secretion of hormones which are carried in the blood to target organs

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

What is endocrine and exocrine?

A

Endocrine- ductless
Exocrine- ducted

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

What is autocrine and paracrine?

A

Autocrine- cells secrete chemicals that bind to receptors on same cell
Paracrine- chemicals diffuse in ECF to affect neighbouring cells

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

What are the 3 types of endocrine hormone?

A

Peptide hormones
Amine hormones
Steroid hormones

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

What are examples of peptide hormones?

A

TRH
FHS
Insulin

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

How are peptide hormones synthesised?

A
  1. Preprohormone formed by amino acids
  2. Enzymes in the ER form inactive prohormone
  3. Prohormone passes from ER through golgi apparatus
  4. Secretory vesicles containing enzymes and prohormone bud off golgi
  5. Enzymes chop prohormone into active peptides and peptide fragments
  6. Vesicles release contents by exocytosis
  7. Hormone moves into circulation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is C-peptide?

A

Inactive fragment cleaved from prohormone

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

What is the clinical relevance of C-peptide?

A

Levels of c peptide measured to indicate endogenous insulin production

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

Which 2 amino acids are amine hormones derived from?

A

Tyrosine
Tryptophan (melatonin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which hormones have a similar action to peptide homrones?

A

Catecholamines (hydrophilic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which hormones have a similar action to steroid hormones?

A

Thyroid hormones (lipophilic)

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

What are steroid hormones derived from?

A

Cholesterol

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

What is the action of steroid hormones?

A

Translation produces new proteins for cell processes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the adenohypophysis?

A

Anterior pituitary

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

How is the anterior pituitary connected to the hypothalamus?

A

Hypothalamic-hypophyseal capillary portal system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the neurohypophysis?

A

Posterior pituitary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How is the posterior pituitary connected to the hypothalamus?

A

Continuation of hypothalamus axons and nerve terminals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What separates the anterior and posterior pituitary?

A

Pars intermedia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are non tropic hormones?

A

Hypothalamus to posterior pituitary to blood
- Vasopressin (ADH)
- Oxytocin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are tropic hormones?

A

Hypothalamus to anterior pituitary. Govern release of AP hormones
- TRH
- CRH
- GHRH
- GHIH
- GnRH
- PRH
- PIH (dopamine)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does TRH control?

A

TSH
Prolactin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does CRH control?

A

ACTH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What does GHRH and GHIH control?

A

GH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What does GnRH control?

A

FH and LH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What does PRH and PIH (dopamine) control?

A

Prolactin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the glucostatic theory?

A

Food intake is determined by blood glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the lipostatic theory?

A

Food intake is determined by fat stores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is an absorptive state?

A

Anabolic phase after eating

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is a post-absorptive state?

A

aka fasting state
Catabolic phase between meals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is normal range for [BG]?

A

4.2-6.3mM (5mM)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are the anabolic actions of insulin?

A

Lowers [BG]:
- Glycogenesis
- Lipogenesis
- Protein synthesis
- Glucose oxidation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are the catabolic actions of glucagon?

A

Raises [BG]:
- Glycogenolysis
- Gluconeogenesis
- Ketogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What do a cells produce?

A

Glucagon

34
Q

What do B cells produce?

A

Insulin

35
Q

What do d cells produce?

A

Somatostatin (GHIH)

36
Q

What do PP cells produce?

A

Pancreatic polypeptide

37
Q

What is the mechanism of insulin secretion?

A
  1. Glucose enters B cell through GLUT transporter
  2. This increases [ATP] by CAC
  3. increased ATP causes K-ATP channel to close
  4. K+ levels rise, depolarising the cell
  5. Calcium channels open
  6. Triggers vesicle exocytosis
38
Q

What is the mechanism of insulin action?

A
  1. Insulin binds to tyrosine kinase receptors on muscle and adipose tissue
  2. Stimulates mobilization of GLUT4 transporters to cell membrane
  3. Glucose enters the cell
39
Q

What tissues are insulin depndent?

A

Muscle
Adipose

40
Q

How does the liver use insulin?

A

Not insulin dependent
GLUT2 transporters
Presence of insulin enhances glucose uptake into hepatocytes by creating a conc. gradient

41
Q

What stimuli increases insulin release?

A

High [BG]
Increased [AA]
Increased glucagon
Increased [gastrin, secretin, CCK]
Vagal nerve activity (Parasympathetic)

42
Q

What hormones form part of the glucose counter-regulatory control system?

A

Glucagon
Epinephrine
Cortisol
Growth Hormone

43
Q

What stimuli increases glucagon release?

A

Low [BG]
High [AA]- prevents hypoglycaemia from insulin release
Sympathetic innervation
Cortisol and stress

44
Q

What is the action of somatostatin?

A

Inhibit activity in GI tract
Suppresses release of both insulin and glucagon (paracrine)

45
Q

What is the effect of exercise on [BG]?

A

Entry of glucose into skeletal muscle is increased despite insulin absence
- GLUT4 transporters migrate without insulin being present

46
Q

What 3 factors affect growth?

A

Genetics
Nutrition
Hormone

47
Q

What are the 2 periods of rapid growth?

A

Infancy- TH, insulin, GH
Puberty- androgens, GH

48
Q

When does GH becomes significant?

A

Around 10 months

49
Q

What is the effects of TH on GH?

A

Permissive effect
Low TH will cause reduced GH action

50
Q

What is growth hormone?

A

aka Somatotropin
Anabolic hormone

51
Q

What neurohomrones control GH release?

A

GHIH (somatostatin)
GHRH

52
Q

What are the actions of GH?

A

Growth of long bones
- Intermediate is IGF-1
Regulation of metabolism
- Anti-insulin effect
- Increases BG

53
Q

What receptors does GH act on?

A

Tyrosine kinase receptors
Phosphorylates intracellular targets

54
Q

What is IGF-1?

A

Insulin like Growth factor, aka Somatomedin C
Stimulates glucose uptake in muscle and in bone
Released by liver in response to GH

55
Q

What stimuli increases GHRH secretion?

A

Reduced energy supply (fasting, exercise, hypoglycaemia)
Increased amino acids
Physical stress and illness
Delta sleep
Sex homrones

56
Q

What stimuli increases GHIH secretion?

A

Glucose
Free fatty acids
Ageing
Cortisol

57
Q

What conditions are caused by hypersecretion of GH?

A

Gigantism
Acromegaly

58
Q

What conditions are caused by hyposecretion of GH?

A

Deficiency of GHRH (hypothalamus)
Deficiency of GHIH (pituitary)
Precocious puberty
Hypothyroid dwarfism

59
Q

What are the 2 thyroid hormones?

A

T3- triiodothyronine
T4- thyroxine

60
Q

What are the 2 thyroid gland cell types?

A

C cells- secrete calcitonin
Follicular cells- support TH synthesis

61
Q

How are THS synthesised?

A
  1. Thyroglobulin made in follicular cells and secreted into colloid with enzymes (thyroxidases)
  2. Iodide enters follicular cells via symporter with NA+
  3. Follicular cells concentrate iodide and transport it to colloid via pendrin transporter
  4. Thyroxidases oxidase iodide to iodine
  5. Iodine combines with tyrosine residues on thyroglobulin to form thyroid hormones
  6. TSH stimulates endocytosis of enzymes and thyroglobulin back into follicular cell
  7. Proteolytic enzymes cut thyroglobulin to release T3 and T4
  8. T3 and T4 pass into plasma and bind to thyroxine binding globulin
62
Q

What thyroid hormone is more physiologically active?

A

T3 as receptors have a higher affinity
T4 is deiodinated to T3 by deiodinase enzymes in plasma

63
Q

Which hormones regulate TH release?

A

TRH (thyrotropin releasing hormone) from hypothalamus
TSH (thyroid stimulating hormone) from AP

64
Q

What is the action of TH?

A

Increases metabolic rate and promotes thermogenesis
Increases gluconeogenesis
Increases proteolysis
Increases lipolysis
Stimulates GH expression (growth)
Brain development in utero

65
Q

What does the adrenal medulla release?

A

Secretes catecholamines:
- Epinephrine
- Norepinephrine

66
Q

What does the adrenal cortex release?

A

Secretes steroid hormones:
1. Zona gomerulosa- aldosterone
2. Zona fasciculata- cortisol
3. Zona reticularis- testosterone

67
Q

Which enzyme is important in aldosterone and cortisol synthesis?

A

21- hydroxylase
Lack causes adrenal hyperplasia

68
Q

Which hormones control cortisol release?

A

CRH from hypothalamus
ACTH from AP

69
Q

What is the action of cortisol?

A

Glucocorticoid: increases BG
- Gluconeogenesis
- Proteolysis
- Lipolysis
- Decreases insulin sensitivity

70
Q

What is the action of aldosterone?

A

Increases Na+ reabsorption (and water)
Increases K+ excretion

Secretion is controlled by RAAS
Therefore effects blood volume and BP

71
Q

What are the roles of calcium in the body?

A

Signalling
Blood clotting
Apoptosis
Skeletal strength
Membrane excitability

72
Q

What is the effect of hypocalcaemia on neurones?

A

Increases Na+ permeability leading to hyperexcitation

73
Q

What is the effect of hypercalcemia on neurones?

A

Decreases Na+ permeability leading to reduced excitability

74
Q

What is the calcium distribution in the body?

A

99% bone
0.9% intracellular
0.1% ECF

75
Q

Describe calcium in the ECF

A

Ca2+ plasma is 2.4 mM

40% protein bound
10% complexes to an anion
50% free (1.2mM)

76
Q

What hormones increase calcium?

A

PTH- parathyroid hormone
Calcitriol- active form of vitamin D
- aka 1,25- dihydroxycholecalciferol

77
Q

What hormone decreases calcium?

A

Calcitonin- released from C cells of thyroid gland

78
Q

What is the action of PTH?

A

Increases [Ca2+]
- Increases bone reabsorption
- Increases kidney reabsorption of calcium
- Increases renal excretion of phosphate so calcium is not deposited back in bone
- Stimulates calcitriol release

79
Q

What is the action of calcitriol?

A

Increases [Ca2+]
- Increases intestinal absorption of calcium

80
Q

Which hormone stimulates calcitriol in lactating women?

A

Prolactin
- Increased demand for Ca2+ for milk production in lactation

81
Q

What is the action of calcitonin?

A

Decreases [Ca2+]
- Decreases bone reabsorption
- Increases renal excretion of calcium

Endocrine System (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions