Brainscape's Knowledge GenomeTM

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


See full index

Endocrinology > The Pituitary Gland & It's disorders > Flashcards

The Pituitary Gland & It's disorders Flashcards

1
Q

Where is the pituitary located in relation to the brain?

A

Pituitary sits outside brain - meninges of brain is on top of pituitary

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

What important structures surround the pituitary gland?

A

Optic chiasm is above pituitary (vision)
Carotid arteries on either side of pituitary
Sphenoid bone below pituitary (sphenoid air sinus within bone)

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

Where is the hypothalamus located in relation to the pituitary?

A

Hypothalamus and cells controlling pituitary lie above pituitary
Portal blood vessels run along hypothalamic stalk

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

Describe the structure of the pituitary

A

Two lobes: Anterior and Posterior

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

Where in the body is the pituitary located?

A

Lies below brain in Sella Turcicia (depression in sphenoid bone)

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

Explain how the anterior lobe develops

A

Anterior Lobe derived from an invagination of the roof of embryonic Rathke’s Pouch (glandular cells)
Anterior hormones produced in pituitary

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

Why is the anterior lobe described as glandular?

A

The anterior pituitary produces and releases its hormones

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

Why is the posterior pituitary known as neurohypophysis?

A

The posterior pituitary stores and releases ADH and oxytocin which are produced in the hypothalamus

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

Describe how the link between the posterior pituitary and hypothalamus develops

A

A notochordal projection forms the pituitary stalk, which connects the gland to the brain and also the posterior lobe of the pituitary (neurohypophysis)

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

How does the posterior pituitary release its hormones?

A

Hormones produced outside pituitary and released onto posterior lobe
Release neurotransmitters directly into circulation as opposed to at a synaptic cleft

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

Describe the pituitary blood supply

A

Dual blood supply
Supply is via long and short pituitary arteries
Drainage is from hypophyseal portal circulation - this begins as a capillary plexus around the Arc (hypothalamus to pituitary)

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

What is meant by portal circulation?

A

Portal veins go from organ capillary bed → organ capillary bed

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

What are the functions of the two pituitary lobes?

A

Anterior: tropic hormones; controls endocrine system

Posterior; ADH and Oxytocin

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

Which hormones are released from the anterior lobe?

A

ACTH; adrenal cortex regulation

TSH; Thyroid hormone regulation

GH; growth (+)

LH / FSH; reproductive control

PRL; breast milk production

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

What hormones does the posterior lobe secrete?

A

Secretes nonapeptide hormones ADH + oxytocin

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

What are the effects of ADH?

A

water balance and regulation

vasoconstriction

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

What is the effect of oxytocin?

A

breast milk expression and uterine contractions

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

What are the 3 layers of the endocrine system?

A

Primary: end organ
Secondary: pituitary
Tertiary: hypothalamus

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

What is the significance of the primary endocrine layer (end organ)?

A

Primary layer - end organ hormone production
Sets endocrine status as either; hyper-, hypo- or eu (normal)
All tests start at end organ to see where pathology is

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

What is the role of the hypothalamus?

A

Hypothalamus takes electrical input from brain stem and higher centres to integrate them into chemical signals to release hormones

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

What is the significance of the pituitary in hormone release?

A

Hormones released into portal veins where they pass to pituitary so the signal can be amplified
~ 6 minutes to synthesise hormones

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

How is the process of hormone release sped up in the body?

A

There are peripheral and central hormones in system to speed up process

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

How do the peripheral and central hormones work in conjunction?

A

As soon as peripheral hormones released, they switch off central hormone production to prevent signals mixing
=> negative feedback

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

What are the clinical signs of a pituitary tumour?

A

Hormone hypersecretion
Space occupying Lesion
Hormone deficiency states

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

What symptoms does a space occupying lesion cause?

A

Headaches
Visual loss (field defect)
Cavernous sinus invasion

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

What is the consequence of hormone deficiency?

A

Interference with surrounding normal pituitary

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

What can cause excess hormone ?

A

Tumours of the Anterior Pituitary can cause syndromes of hormone excess

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

What are the effects of excess anterior hormones?

A

GH (IGF-1)
- acromegaly

ACTH
- Cushing’s disease

TSH
- Secondary thyrotoxicosis

LH / FSH
- non-functioning pituitary tumour

PRL
- prolactinoma

29
Q

What are the effects of growth hormone?

A

GH acts on liver to produce IGF-1 which acts on long bones to enables chondrocytes to grow and lay down more cartilage which osteophyte to cause bone growth

30
Q

As well as GH, what other factors are required for growth?

A

Need to have sufficient energy and nutrients for growth

31
Q

What are the metabolic effects fo growth hormone?

A

↑lipolysis and FFA
↑protein synthesis and a.a. uptake
↑gluconeogenesis in liver

32
Q

What are the systemic effects of acromegaly?

A 
Acral enlargement 
Macroglossia; can cause disruptive sleep apnoea 
Carpal tunnel syndrome
Increased skin thickness + sweating
Change appearance
- Interdental spacing ; overgrowth of jaw 
Visceral enlargement
Metabolic changes
Diabetes mellitus
Insulin resistance 
Reduced total cholesterol 
Increased TGs
33
Q

What are the dangerous clinical consequences of acromegaly?

A

Cardiomyopathy
Hypertension

Bowel polyps
Colonic cancer

Multinodular goiter
Hypogonadism

Arthropathy
OSA

34
Q

What are the effects of cortisol on plasma [glucose]?

A

↑gluconeogenesis
↓glucose utilisation
↑glycogenolysis
↑glycogen storage

  • increases plasma glucose
35
Q

What are the systemic metabolic effects of cortisol?

A 
Increases lipolysis → Provides energy
Proteins are catabolised → releases amino acids 
Na+ and H₂O retention maintains BP
Anti-inflammatory 
Increased Gastric Acid production
36
Q

What are the symptoms of Cushing’s syndrome caused by disruption of fat and protein metabolism?

A 
Changes in body shapes
Central obesity 
Moon face
Buffalo hump
Thin skin, easy bruising
Osteoporosis (brittle bones)
Diabetes
37
Q

What are the symptoms of sex hormone imbalance due to Cushing’s?

A

Excess hair growth
Irregular periods
Problems conceiving
Impotence

38
Q

How does cushing’s sydrome effect Na and water balance?

A

High blood pressure

Fluid retention

39
Q

How does PRL control differ to other anterior hormones?

A

Stimulated externally (baby on nipple)

40
Q

How is PRL release regulated?

A

Tonic release of DA inhibits PRL release

+ve feedback

41
Q

How is PRL secretion achieved?

A

Afferent limb - neuronal signal from nipple to hypothalamus to switch off dopamine production - surge in PRL production
Take baby off breast switches off PRL production as afferent limb no longer stimulated

42
Q

What drugs interfere with DA and PRL secretion?

A

Antiemetics
Antipsychotics
OCP/HRT

43
Q

What does excess PRL (hypogonadism) cause?

A 
Infertility
Amenorrhoea
Reduced libido
Oligomenorrhea
Galactorrhoea 
Impotence
44
Q

How is hypogonadism treated?

A

dopamine agonists:-

  • Bromocriptine
  • Cabergoline
45
Q

What are non-functioning pituitary tumours?

A

No syndrome of hormone excess produced

- 30% of all pituitary tumours

46
Q

How do non-functioning pituitary tumours cause symptoms?

A

Cause symptoms due to space occupation

  • Headache
  • Visual field defects
  • Nerve palsies
  • Interfere w/ pituitary function; hormone deficiencies
47
Q

How do we treat non-functioning pituitary tumours?

A

surgery (transsphenoidal approach) ± radiotherapy

- No effective medical therapy

48
Q

How do pituitary tumours impair vision?

A

Tumours can expand and damage optical chiasm

49
Q

What is the optic chiasm?

A

crossing point of nasal and temporal retina

50
Q

Explain how retinal neuron fibres allow us to see

A

Nasal retina and temporal retina on opposite side look at same place of object
All neurones from nasal retina cross and line up with temporal neurones on other side - those two neurones looking at same piece of object go back to one piece of brain for interpretation

51
Q

What is bitemporal hemianopia?

A 
Bitemporal hemianopia (lost temporal visual field as nasal fibres damaged)  
Starts as bitemporal upper quadrantanopia as damages bottom cells of optic chiasm first (impairing top of visual field)
52
Q

Outline the decrease in pituitary function as tumours expand

A

Function decreases in following order:

  1. LH /FSH - sex
  2. GH - growth
  3. TSH - metabolism
  4. ACTH - survival
  5. ↑ PRL - stalk compression
53
Q

Why does PRL increase with expanding tumours?

A

PRL increases as dopamine levels decrease

54
Q

How are pituitary adenomas treated?

A

Surgery

  • Transsphenoidal
  • (Adrenalectomy - Nelson’s Syndrome)

Radiotherapy
- Slow

Drugs

  • Block hormone production
  • Stop hormone release
55
Q

What causes pituitary failure?

A 
Tumour (most common)
- Benign or malignant
Trauma
Infection (e.g. TB; disrupts meninges)
Inflammation
- Sarcoidosis
- Histiocytosis
Iatrogenic
56
Q

What does hypothyroidism cause and how is it treated?

A

Bradycardia, weight gain, cold tolerance, hypothermia, constipation

Treatment: thyroxine

57
Q

What are the symptoms and treatments of reduced cortisol?

A

Tiredness, weakness, anorexia, postural hypotension, myalgia

Treatment: hydrocortisone

58
Q

What is the effect of decrease sex streoids production?

A

Oligomennorrhoea, Reduced libido, hot flushes, reduced body hair

Treatment: testosterone, oestrogen

59
Q

What are the consequences of decreased growth hormone and how is it treated?

A

Tired, central weight gain

Treatment: growth hormone

60
Q

What is the release of Vasopressin stimulated by?

A

Increased plasma osmolality
Decreased BP (baroreceptors
↑PaCO₂ ↓PaO₂: shock
Cortisol, sex steroids, angiotensin II

61
Q

What are the effects of ADH/ vasopressin?

A

Collecting ducts
↑ H₂O permeability
Reabsorption of free water
Vasoconstriction

62
Q

What is the cause of diabetes insipidus?

A

Underproduction of ADH

63
Q

What are the 2 types of Diabetes Insipidus?

A

Cranial - lack of production

Nephrogenic - Receptor in kidney resistance

64
Q

What is SIADH?

A

Syndrome of Inappropriate ADH (SIADH)

Too much ADH

65
Q

What are the causes of SIADH?

A 
Brain injury / infection
Lung cancer / infection asthma IPPV
Metabolic
- Hypothyroidism
- Addison’s
66
Q

How can we clinically detect SIADH?

A

↓Plasma Na+ (<130 mmol/L)
↓Plasma Osmolality (<270 mOsm/Kg)
↑Urine osmolality (>100 mOsm/Kg)
↑Urine sodium (>50 mmol/L)

67
Q

How do we treat SIADH?

A

fluid restriction

68
Q

How is diabetes insipidus diagnosed?

A

Polyuria (>3L)
Polydipsia
- ↑Na+, ↑plasma osmolality
- ↓Urine osmolality, ↓Urine Na+

Endocrinology (12 decks)

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