Endo Intro to endocronology Flashcards

1
Q

What is homeostasis?

A

Maintenance of a steady state/internal
environment

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2
Q

What elements stimulate hypothalamus if there is a change in temperature?

A

-Cutaneous temperature receptors
-Hypothalamic temperature receptors

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3
Q

What is done to counter heat loss?

A

sweating,
vasodilatation

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4
Q

What is done to counter heat gain?

A

shivering,
vasoconstriction,
metabolism

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5
Q

What happens to the set point when the body has an infection?

A

With infection the set point
is changed and body
temperature rises

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6
Q

What are the benefits of an increase in body temperature during an infection?

A

– Inhibits bacterial growth
– Speeds up metabolic reactions
– Increases delivery of white blood cells to infection sites

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7
Q

What is the homeostatic control of blood pressure?

A
  1. Medulla signals to heart and peripheral resistance
  2. Baroreceptors(stretch receptors) signal the medulla tor control blood pressure with negative feedback.
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8
Q

What does hypertension do that causes an increase in blood pressure?

A

Resetting the
sensitivity of the
baroreceptors

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9
Q

What is the control of circulating cortisol concentrations?

A
  1. Hypothalamus secretes corticotropin releasing hormone which acts on the anterior pituitary gland.
  2. This leads to the secretion of ACTH that acts on the adrenal cortex resulting in the release of cortisol.
  3. Negative feedback acting on the hypothalamus control circulating cortisol concentrations
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10
Q

What are the effectors that are involved in circulating cortisol concentrations?

A
  1. Anterior pituitary gland
  2. Adrenal cortex
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11
Q

What increases set point in control of circulating cortisol concentrations?

A
  1. Stress
  2. Circadian rhythm
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12
Q

How does the positive feedback control system work in haemostasis?

A
  1. Break or tear in blood vessel wall
  2. Clotting occurs as platelets adhere to site and release chemicals
  3. Released chemicals attract more platelets
  4. Clotting proceeds until break is sealed by newly formed clot
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13
Q

How does the positive feedback system in the control of uterine contractions in labour work?

A
  1. In labour oxytocin
    stimulates contraction
    of uterine muscles
  2. Cervix dilates and
    activate stretch
    receptors
  3. Action potentials
    signal to
    hypothalamus
  4. Stimulates further
    release of oxytocin
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14
Q

What are major endocrine glands?

A
  • Hypothalamus
  • Pituitary gland
  • Thyroid, adrenal cortex, gonads
  • Pancreas
  • Parathyroid glands
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15
Q

What does the hypothalamus secrete?

A

Releasing & inhibiting hormones

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16
Q

What does the anterior lobe of pituitary gland secrete?

A

Trophic hormones

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17
Q

What does the posterior lobe of the pituitary gland secrete?

A

oxytocin & vasopressin (ADH)

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18
Q

What does the thyroid gland secrete?

A

Thyroxine, tri-iodothyronine

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19
Q

What does cortex of the adrenal gland secrete?

A

Cortisol, aldosterone

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20
Q

What does the medulla secrete of the adrenal gland secrete?

A

Adrenaline/noradrenaline

21
Q

What do the gonads secrete?

A

Oestrogens, androgens, progestagens

22
Q

What does the pancreas secrete?

A

Insulin, glucagon

23
Q

What do parathyroid glands secrete?

A

Parathyroid hormone

24
Q

How do endocrine hormones work?

A

Hormones released by an endocrine cell into the general circulation and acting on distant target sites

25
How do paracrine hormones work?
Hormones released by an endocrine cell which at locally on adjacent cells
26
How do autocrine hormones work?
Hormones released by a cell which act back on the same cell
27
How do intracrine hormones work?
Conversion of an inactive hormone to an active hormone that acts within that cell
28
What are the general functions of hormones?
1. Reproduction, growth and development 2. Maintenance of internal environment 3. Energy production, utilisation and storage
29
What are the different chemical classification of hormones?
1. Protein/peptide hormones 2. Steroid hormones (cholesterol) 3. Amino acid derivatives(tyrosine/tryptophan) 4. Fatty acid derivatives
30
What is the half life of protein/peptide hormones and how are they transported?
-Half life is minutes -Transport is mainly unbound
31
What is the half life of tyrosine derivatives(catecholamines), thyroid hormones and how are they transported?
-Seconds(CA's) hours(thyroid hormones) -Transport of thyroid hormones is bound to plasma proteins
32
What is the half life of cholesterol derived hormones and how are they transported?
-Half life is hours-days -Transport is bound to plasma proteins
33
Where are the magnocellular neurons and what do they synthesise and release?
Magnocellular neurons in the hypothalamus synthesise and release posterior pituitary hormones
34
Where do other neurosecretory cells in the hypothalamus release their hormones into?
release their hormones into the portal capillaries in which they are transported directly to endocrine cells of the anterior pituitary gland
35
What are the glands controlled by the hypothalamic-pituitary axis?What are the hormones and what do they act on?
-Hypothalamus stimulate anterior pituitary gland with releasing/inhibiting neurohormones. -Anterior pituitary gland releases trophic hormones TSH, ACTH and LH/FSH -TSH acts on thyroid -ACTH acts on adrenal cortex -LH/FSH act on Gonads
36
What and where does a release of corticotropin releasing hormone(CRH) increase release of and from where?
-CRH released from hypothalamus -Acts on anterior pituitary to increase release of ACTH
37
Where is TSH released from and what does it increase secretion of and from where?
-TRH released from hypothalamus -Acts on anterior pituitary to increase release of TSH
38
Where is Growth hormone inhibiting hormone(GHIH) released from, what is it also known as and what does it decrease release of and from where?
-GHIH is released from hypothalamus -Also known as somatostatin -Acts on anterior pituitary to reduce release of TSH
39
Where is Gonadotropin releasing hormone(GnRH) released from and where does it act and what does it increase release of?
-GnRH is released from hypothalamus -Acts on anterior pituitary to increase release of LH and FSH
40
Where is dopamine released from and where does it act and what does it decrease release of?
-Dopamine released from hypothalamus -Acts on anterior pituitary to decrease release of prolactin
41
Where is growth hormone releasing hormone(GHRH) released from, where does it act and what does it increase release of?
-GHRH released from hypothalamus -Acts on anterior pituitary to increase release of growth hormone
42
Where is growth hormone inhibiting hormone(GHIH) released from, where does it act and what does it decrease release of?
-GHIH released from hypothalamus -Acts on anterior pituitary to decrease release of GH
43
What processes is cortisol involved in?
-Gluconeogenesis -Protein mobilisation -Fat mobilisation -Anti-inflammatory effects
44
What does a lack of cortisol cause?
Addison's disease
45
What does an excess of cortisol cause?
Cushing's disease
46
What is addison's disease?
Deficiency of adrenocortical hormones
47
What is cushing's disease?
Excess glucocorticoids
48
What causes testicular feminization?
Complete resistance to circulating androgens
49
What does vitamin D resistance cause?
Rickets