Endocrine System Flashcards

1
Q

What are the endocrine system’s actions mediated by?

A

Hormones

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2
Q

Which regulatory systems does the endocrine system control?

A

1- Regulation of cellular metabolism
2- Maintenance of homeostasis
3- Sexual development and reproduction
4- Growth and development from child to adult
5- Modulating long term behaviour such as sleep and mood

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3
Q

What are the two types of glands?

A

1- Endocrine glands

2- Exocrine glands

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4
Q

What are the main differences between endocrine and exocrine glands?

A

1- Endocrine glands have no ducts and secrete hormone directly into the blood
2- Exocrine glands contains ducts formed by epithelial cells

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5
Q

What are hormones?

A

1- Chemical messengers

2- Act on target cells through specific receptors

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6
Q

What are the three classes of hormones?

A

1- Proteins
2- Steroids
3- Amino acid derivatives

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7
Q

Describe the structure of an exocrine gland.

A

1- Secretory cells
2- Acinus
3- Basement membrane
4- Duct with lumen

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8
Q

What do salivary glands, sebaceous glands and sweat glands all open onto?

A

Skin

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9
Q

What does the pancreatic duct open into?

A

Duodenum

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10
Q

What is paracrine secretion?

A

1- Cell-to-cell communication
2- Cell secretes factors which induce changes only in adjacent cells
3- Paracrine factors diffuse over short distances

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11
Q

What are paracrine factors made of?

A

Polypeptides

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12
Q

Why is paracrine secretion relevant/important in embryogenesis?

A

1- Gradients of polypeptides influence developmental change

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13
Q

What are the four families of paracrine receptors?

A

1- Fibroblast growth factor (FGF) family
2- Hedgehog family
3- WnT family
4- TGF-β superfamily

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14
Q

What are the ten organs of the endocrine system?

A
1- Pineal gland
2- Pituitary gland
3- Hypothalamus
4- Thyroid glands
5- Parathyroid glands
6- Thymus
7- Adrenal glands
8- Pancreas
9- Ovaries
10- Testes
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15
Q

How are steroid and thyroid hormones carried in the blood and why?

A
1- Via specific carrier/binding proteins
2- Improved solubility
3- Increased half-life
4- Provides a reserve in the blood
5- Inactive until freed from carrier
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16
Q

How do hormones act?

A

By binding onto receptor

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17
Q

Where can hormone receptors be found?

A

1- Cell membrane receptors

2- Intracellular receptors in the nucleus

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18
Q

What types of hormones bind to cell membrane receptors?

A

1- Peptides
2- Glycoproteins
3- Catecholamines

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19
Q

What types of hormones bind to intracellular receptors in the nucleus?

A

1- Steroids

2- Thyroid hormones

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20
Q

hat are steroid hormones synthesised from?

A

Cholesterol

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21
Q

What are amino acid derived hormones?

A

1- Thyroid hormones

2- E.g. catecholamines such as adrenalin, dopamine and noradrenaline

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22
Q

What does the anterior pituitary develop from?

A

Epithelium of mouth

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23
Q

What does the posterior pituitary develop from?

A

1- Downgrowth of the hypothalamus

2- Consists of nerve fibres

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24
Q

What is the main endocrine axis/regulation?

A

1- Hypothalamus stimulates pituitary gland

2- Pituitary gland stimulates other distant endocrine organs

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25
Q

Why are target tissues of one hormone another endocrine gland? (What does this allow?)

A

Allows for amplification and fine control

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26
Q

What is the role of the hypothalamus?

A

1- Stimulates and controls the secretion and release of pituitary hormones
2- Releases hormones to control release of anterior pituitary hormones
3- Secretes hormones which are stored and released by posterior lobe of posterior pituitary gland

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27
Q

What is the role of pituitary hormones?

A

1- Stimulated by pituitary hormones

2- Stimulate and control other endocrine glands

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28
Q

How does the hypothalamus control the anterior pituitary gland?

A

1- Releases hormones which stimulate anterior pituitary gland
2- E.g. prolactin release is controlled by hypothalamic inhibiting factor

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29
Q

What hormones does the posterior lobe of the pituitary gland store and release?

A

1- Oxytocin

2- Antidiuretic hormone (ADH) (also called Vasopressin)

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30
Q

What six hormones does the anterior pituitary gland secrete?

A
1- Growth hormone (GH)
2- Thyroid stimulating hormone (TSH)
3- Adrenocortitropic hormone (ACTH)
4- Follicle stimulating hormone (FSH)
5- Luteinising hormone (LH)
6- Prolactin
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31
Q

What does the growth hormone affect?

A

Stimulates growth of body by increasing levels of glucose free fatty acids to increase cell division

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32
Q

What is TSH’s target organ?

A

Thyroid

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33
Q

What does prolactin effect?

A

Lactation/milk production

34
Q

What is ACTH’s target organ?

A

Adrenal glands

35
Q

What is LH’s target organ?

A

Gonads (ovaries or testes)

36
Q

What is FSH’s target organ?

A

Gonads (ovaries or testes)

37
Q

What tissue does the posterior lobe of the pituitary gland consist of?

A

Neural tissue

38
Q

What is the role of the posterior lobe of the pituitary gland?

A

1- Stores hormones which are secreted when stimulated by neurosecretory hormones from the hypothalamus
2- These hormones are transported via neuronal axis in the stalk to the posterior lobe
3- Releases two hormones: ADH and oxytocin

39
Q

What is the effect of oxytocin?

A
1- Helps with birth
2- Social bonding
3- Bonding to baby
4- Helps with breastfeeding
5-Helps with contractions when delivering a child
40
Q

What is the target organ of ADH?

A

1- Kidney

2- Retains water

41
Q

What are the steps of the hypothaamo-hypophyseal-gonadal axis?

A

1- Hypothalamus secretes GnRH
2- GnRH stimulates hypophysis (pituitary gland) to secrete gonadotrophins
3- Gonadotrophins stimulate gonads to release steroids

42
Q

How is GnRH inhibited?

A

1- Negative feedback

2- Inhibited by high levels of gonadal steroids

43
Q

What is a pituitary adenoma?

A

Tumour which may occur in the pituitary gland

44
Q

What can pituitary adenomas lead to?

A
1- Acromegaly
2- Excess production of GH
3- Leads to excessive growth
4- Typical features include:
a. Large hands and feet
b. Large and prominent facial features
c. Enlarged tongue
d. Abnormally tall height
45
Q

What is the cause of acromegaly?

A

1- Pituitary adenoma

2- Excess production of GH

46
Q

What are typical features of acromegaly?

A

1- Large hands and feet
2- Large and prominent facial features
3- Enlarged tongue
4- Abnormally tall height

47
Q

What is the position of the thyroid gland?

A

Anterior to the trachea in the neck

48
Q

What does the thyroid gland develop from?

A

Down growth from the tongue, leaves behind foramen caecum

49
Q

Describe the histology of thyroid cells

A

1- Follicle
2- Follicular cells
3- Colloid

50
Q

What do follicular cells secrete?

A

1- Tri-iodothyronine (T3)
2- Thyroxine (T4)
3- Secretion requires iodine

51
Q

What substance to follicular cells need to secrete their hormones?

A

Iodine

52
Q

Where are T3 and T4 stored?

A

1- In colloid of thyroid cells

2- Colloid is made of thyrobglobulin

53
Q

What does thyroxin regulate?

A

1- Rate of metabolism
2- Protein development for growth and development
3- Sensitivity of cells to other hormones

54
Q

What do parafollicular cells produce?

A

Calcitonin

55
Q

What does calcitonin regulate?

A

1- Calcium homeostasis

2- Stimulates osteoblasts

56
Q

What do parathyroid glands develop from?

A

Wall of the pharynx

57
Q

How many parathyroid glands are there?

A

Two pairs of glands

58
Q

Where are the parathyroid glands positioned?

A

Embedded in the posterior aspect of the thyroid

59
Q

What do the parathyroid glands produce?

A

Parathyroid hormone

60
Q

What does the parathyroid hormone regulate?

A

1- Calcium homeostasis

2- Stimulates osteoclasts to break down bone matrix to increase Ca2+ levels in blood

61
Q

Describe the structure and layers of the adrenal glands.

A
1- Medulla contains neural crest cells
2- Cortex contains three layers:
a. Zona glomerulosa
b. Zona fasciculata
c. Zona reticulatis
62
Q

Where does the adrenal cortex develop from?

A

Mesoderm of posterior abdominal wall

63
Q

What kind of hormones does the adrenal cortex produce?

A

Steroids

64
Q

What does Z. glomerulosa produce?

A

1- Mineralocorticoids

2- E.g. Aldosterone

65
Q

What does Z. fasciculata produce?

A

1- Glucocorticoids

2- E.g. cortisol

66
Q

What does Z. reticularis produce?

A

reticularis produce?
1- Sex steroids
2- E.g. androgens

67
Q

Where does the adrenal medulla develop from?

A

From neural crest cells or from neuroectoderm

68
Q

What are chromaffin cells?

A

1- Cells in the adrenal medulla

2- Produce catecholamines e.g. epinephrine, norepinephrine, dopamine

69
Q

What does the adrenal medulla have a direct connection with?

A

1- Sympathetic nervous system

2- Helps control fight or flight response

70
Q

What do chromaffin cells produce?

A

1- Catecholamines:
2- Epinephrine
3- Norepinephrine
4- Dopamine

71
Q

What is Cushing’s syndrome?

A
1- Condition caused by overproduction of cortisol
2- Typical indications: 
a. hypertension
b. round red face
c. abdominal obesity
72
Q

What are indications of Cushing’s syndrome?

A

1- Hypertension
2- Round, red face
3- Abdominal obesity

73
Q

What does the pancreas develop from?

A

1- Outgrowth of the gut tube

2- Closely associated with development of gall bladder

74
Q

Where do pancreatic ducts empty into?

A

Duodenum

75
Q

What does the exocrine pancreas produce?

A

1- Pancreatic amylase

2- By acinar cells

76
Q

What does the endocrine pancreas produce?

A

1- Glucagon
2- By alpha cells in islets of Langerhans
3- Insulin
4- By beta cells in islets of Langerhans

77
Q

What is an excretory duct?

A

Generally excretes waste products

78
Q

What is the structure of the intestinal glands?

A

Simple tubular

79
Q

What is the structure of the sweat glands?

A

Simple coiled tubular

80
Q

What is the structure of the stomach and uterus?

A

Simple tubular branched

81
Q

What is the structure of the sebaceous glands of the skin?

A

Simple acinar or alveolar gland

82
Q

What are colloid cells made of

A

Thyroglobulin