Endocrine

Question 1

Growth Hormone Deficiency Symptoms and treatment

Answer 1

Injection with GH. 
Reduced growth (pituitary dwarfs with normal body proportions)

Question 2

Achondroplasia

Answer 2

Mutation in FGFR3, bodily proportions not normal

Question 3

Gigantism vs Acromegaly

Answer 3

Gigantism: Hypersecretion of GH before Puberty
Acromegaly: In Adulthood (Pituitary tumour).
Increased Cartilagninous growth, enlargement of hands, feet and tongue

Question 4

Treatment for GH excess

Answer 4

Somatostatin Analogues

GH-Receptor Antagonist

Question 5

Other Factors Involved in growth

Answer 5

Growth Factors: promote locally
Insulin: essential for normal
Thyroid: Permissive for growth, hypothyroidism causes short stature
Gonadal Steroids: Pubertal growth spurt + long bone growth
Glucocorticoids: inhibit growth in excess

Question 6

Effects of GF

Answer 6

Direct effect
Indirect effect via IGF (Somatomedin) via Liver
DIABETOGENIC, Synergistic with CORTISOL

Question 7

Regulation of GH and their production

Answer 7

GHRH: Arcuate Hypothalamic Neurons –> Somatotrophs (GPCRs, cAMP)
Somatostatin: Paraventricular Hypothalamic Neurons

Question 8

Arginine and GH release

Answer 8

Stimulates GH release, used to clinically diagnose GH deficiency

Question 9

GH feedback loops

Answer 9

Short Feedback: GH on Hypothalamus
Long Direct Feedback: IGF1 on Pituitary
Long Indirect Fb: IGF1 on Hypothalamus

Question 10

GH Structure

Answer 10

Polypeptide LONG (191 AA)
2 disulfide bridges

Question 11

Hyperthyroidism Causes

Answer 11

Overactivity of Thyroid Gland

Autoimmune response: Graves Disease

Question 12

Hyperthyroidism Symptoms

Answer 12

Weight Loss
Sweating
Muscle Weakness
Staring Eyes

Question 13

Hyperthyroidism Treatment

Answer 13

Block: Anti-thyroid drugs

Destruction of thyroid by radioiodine / surgery

Question 14

Hypothyroidism Effects

Answer 14

Weight Gain
Cold Extrimities
Lethargic
Cretinism in late fetal / early post natal development

Question 15

Hypothyrodism Cause and Treatment

Answer 15

1. Iodine Deficiency
2. Disease / Congenital defect on thyroid
3. Lack of TSH

Treatment: oral administration of thyroxine

Question 16

Thyroid Hormone and Calorigenesis (Heat Production)

Answer 16

Peripheral Effect: Muscles

1. NaKx
2. Uncoupling Protein 3
3. SERCA calcium cycling
4. Glycerol Phosphate Dehydrogenase

Central: Ventromedial hypothalamus

1. Decreased AMPK
2. SNS brown adipose to increase UP1

Question 17

Thyroid Synthesis, and TSH actions

Answer 17

1. Uptake of Iodide by Sodium-Iodine transporter (SLC5A5)
2. Oxidation of iodide into iodine
3. Iodide uptake onto thyrosine on Thyroglobulin protein
4. Endocytosis of Thyroglobulin protein
5. Degradation and release into bloodstream.

TSH affects everything except 3

Question 18

Control of Thyroid Secretion (regulation Axis)

Answer 18

1. Long Indirect Feedback on hypothalamus
2. Long Direct feedback on pituitary (targets DI)
3. DI at target cells converting T4 to T3 (Tri-iodothyronine)

Question 19

Histology of Thyroid Gland

Answer 19

1. C Parafollicular cells: Calcitonin

2. Thyroid Follicles; colloid material has thyroxine and tri-iodothyronine (T3)

Question 20

Hypoadrenocorticism Primary Vs Secondary

Answer 20

Primary: Addisons Disease
- Deficiency of both Glucorticoids and mineralocortooids

Secondary:
- Deficiency of glucocorticoids, and sex hormone productions

Question 21

Effects of Primary vs secondary Hypoadrenocorticism

Answer 21

Primary

1. Hypotension (Aldosterone lack)
2. Tiredness
3. PIGMENTATION

Secondary

1. NO PIGMENTATION
2. Loss of body hair

Question 22

Causes of Primary Vs Secondary Hypoadrenocorticism

Answer 22

Primary
Destruction / autoimmune reaction of adrenals

Secondary
Lack of ACTH (Adrenocorticotrophic Hormone)

Question 23

Congenital Adrenal Hyperplasia

Answer 23

• 21-Hydroxylase Deficiency
• Lack in BOTH aldosterone AND cortisol production
• Increased CRH-ACTH levels to compensate
• Shunting of progesterone ONLY to testosterone
• Masculinsation of females
• Low mineralocorticoid

Question 24

Hyperadrenocorticism (Cushing’s sydrome) Causes

Answer 24

Excess Glucocorticoids

• Adrenal Gland Tumour
• Increased ACTH / Increased CRH –> Skin Pigmentation

Question 25

Cushing's Syndrome Symptoms

Answer 25

Immune system suppression Weight gain Rosy Cheeks Skeletal Muscle Wasting

Question 26

Why does ACTH cause pigmentation too?

Answer 26

Pigmentation due to effect of ACTH on Melanocytes: Either due to 1. Hyperadrenocorticism 2. Primary Hypoalrenocorticism (oversecretion of ADH to overcompensate for weak adrenals)

Question 27

Hormones of Adrenal Medulla

Answer 27

Tyrosine Derived Dopamine --> NA --> A Catecholamines: from Chromaffin Cells

Question 28

Cortisol Actions

Answer 28

1. Glucocorticoid: raises blood glucose 2. Reduced inflammation (inhibits NO, prostaglandins) 3. Reduce immune response: Inteleukins by macrophages 4. Fetus: prep for birth, including surfactant 5. CNS: Alter mood 6. Vasoconstriction for BP, and erythropoiesis

Question 29

ACTH Secretion

Answer 29

``` Corticotrophin Releasing Hormone Adrenocorticotrophic Hormone (ACTH) by Pituitary corticotrophs ```

Question 30

Which hormones are Circadian

Answer 30

1. Cortisol 2. GH 3. Prolactin Cortisol: rises in the morning due to low blood sugar, decreases at night. Other two: Elevated in sleep

Question 31

Which Hormones are Pulsatile

Answer 31

LH, FSH and Testosterone: | Ensures no down regulation of pituitary receptors

Question 32

Evidence for Anterior Pituitary Secretions by hypothalamic releasing hormones

Answer 32

1. Hypothalamic Lesions --> Endocrine gland atrophy 2. Ligation of Pituitary stalk: Atrophy 3. Electrical stimulation of hypothalamus --> AP secretion 4. Transplantation of AP needs blood supply with hypothalamus

Question 33

Hypothalamic Hormones Controlling AP secretions

Answer 33

``` CRH TRH GnRH GHRH SMS (Somatostatin) Dopamine ```

Question 34

4 Types of Hormones

Answer 34

Steroid Peptide Amine Hormones (tyrosine / tryptophan derived) Arachidonic Acid Derivatives (COX and inflammation)

Question 35

Basal Metabolic Rate

Answer 35

Energy needed to keep resting individual alive: Doesnt account for movement and normal environmental temp

Question 36

Measurement of BMR (basal metabolic Rate)

Answer 36

Intake or consumption of oxygen / CO2 released: translate into heat equivalent.

Question 37

What are the Incretins

Answer 37

Feedforward insulin release GLP-1 (glucagon Like Peptide) GIP (Gastric Inhibitory peptide)

Question 38

Hypothalamic Areas for food intake

Answer 38

``` Lateral: Food intake (Oretic) Ventromedial Nucleus (VMN): Food restriction (Anoretic) ```

Question 39

Types of Leptin Mutation

Answer 39

Ob/ob Leptin gene vs db/db receptor gene. Db/db: high levels of Leptin

Question 40

Ghrelin Secretion

Answer 40

- P/D1 cells in Fundus of stomach | - e-cells of islets of langerhans

Question 41

Ghrelin Effect

Answer 41

1. GH release from pituitary | 2. Oretic (HUNGER): NPY/AgRP neurons in hypothalamus

Question 42

Arcuate Nucleus Importance in Food intake

Answer 42

Oretic: (Neuropeptide Y) and Agouti-related peptide (AgRP) Anorectic: POMC (pro-opio melano cortin receptors) / CART Acts on Melanocortin receptors (MC3/4)

Question 43

Hormones that DECREASE food intake

Answer 43

``` Leptin Insulin CCK Incretins (GLP-1) Peptide YY ```

Question 44

Roux En Y additional benefit

Answer 44

Reduces Ghrelin secretion

Question 45

Steroid / Thyroid Hormones transport

Answer 45

Fat soluble: Across cell membrane | Associated with specific binding proteins