Functional anatomy and physiology

Question 1

What does the endocrine system consist of?

Answer 1

pituitary gland, thyroid, parathyroid, adrenal
glands, pancreas, ovary and testes

Question 2

What are the 4 classes of hormones?

Answer 2

1. Peptides
2. Amines
3. Iodothyronines
4. Cholesterol derivatives and steroids

Question 3

How are water soluble hormones transported?

Answer 3

Unbound to proteins

Question 4

How do water soluble hormones interact with cells?

Answer 4

Bind to surface receptor

Question 5

What is the half life of water soluble hormones?

Answer 5

Short

Question 6

How quickly is the clearance for water soluble hormones?

Answer 6

Fast

Question 7

What are examples of water soluble hormones?

Answer 7

Peptides, monoamines

Question 8

How are lipid soluble hormones transported?

Answer 8

Protein bound

Question 9

How do lipid soluble hormones interact with cells?

Answer 9

Diffusing into cells

Question 10

What is the half life of lipid soluble hormones?

Answer 10

Long

Question 11

How quickly is the clearance for lipid soluble hormones?

Answer 11

Slow

Question 12

What are examples of lipid soluble hormones?

Answer 12

Thyroid hormones, steroids

Question 13

Are peptides / monoamines stored?

Answer 13

Yes stored in vesicles

Question 14

Are steroids stored?

Answer 14

No synthesised on demand

Question 15

Describe features of peptide hormones

Answer 15

• Peptides vary in length
• Can be linear or ring structures and can bind to carbohydrates
• Peptide hormones can be used as granular store

Question 16

What is the process of the synthesis of peptide hormones?

Answer 16

Synthesis: preprohormone –> prohormone
Packaging: Prohormone –> hormone
Storage: hormone
Secretion: hormone

Question 17

Describe features of amine hormones

Answer 17

Water soluble, stored in secretory granules, release pulsatile, rapid clearance

Question 18

Describe features of iodothyronines

Answer 18

• Thyroid hormones are not water soluble
  
  • 99% is protein bound
• Only 20% of T3 in the circulation is secreted directly by thyroid
• Secretory cells release thyroglobulin into colloid – acts as base for thyroid hormone synthesis
• Incorporation of iodine on tyrosine molecules to form iodothyrosines
• Conjugation of iodothyrosines gives rise to T3 and T4 and stored in colloid bound to thyroglobulin
• T3 and T4 are
  cleaved from thyroglobulin when TSH stimulates the movement of colloid into secretory
  cell

Question 19

Which type of hormone has receptors on cell membranes?

Answer 19

Peptide

Question 20

Which type of hormone has receptors mainly in cytoplasm?

Answer 20

Steroid

Question 21

What are some examples of steroid hormones who’s receptors are in cytoplasm?

Answer 21

Glucocorticoids (cortisol)
Mineralocorticoids (aldosterone)
Androgens (testosterone)
Progesterone

Question 22

Which type of hormone mainly has receptors in the nucleus?

Answer 22

Thyroid

Question 23

Which hormones have receptors in the nucleus?

Answer 23

Oestrogen
Thyroid hormone
Vitamin D

Question 24

What are the different types of cholesterol derivatives and steroid hormones?

Answer 24

1. Vitamin D
2. Adrenocortical and gonadal steroids

Question 25

What are features of vitamin D?

Answer 25

• Fat soluble
• Enters cells directly to nucleus to stimulate mRNA production
• Transported by Vitamin D binding protein

Question 26

What are features of adrenocortical and gonadal steroids?

Answer 26

• 95% protein bound
• After entering cell
  
  1. Pass to nucleus to induce
     response
  2. Altered to active metabolite
  3. Bind to a cytoplasmic receptor

Question 27

Describe steroid actions

Answer 27

1. Steroid hormone diffuse through plasma membrane and binds to receptor
2. Receptor-hormone complex enters nucleus
3. Receptor-hormone complex binds to GRE (glucocorticoid-response elements)
4. Binding initiates transcription of gene to mRNA
5. mRNA directs protein synthesis

Question 28

Describe the control of hormone secretion

Answer 28

• Basal secretion – continuously or pulsatile
• Release inhibiting factors – dopamine inhibiting prolactin, sum of positive and negative effects (GHRH and somatostatin on GH)
• Releasing factors

Question 29

Describe the control of hormone action

Answer 29

• Hormone metabolism: increased metabolism to reduce function
• Hormone receptor induction: induction of LH receptors by FSH in follicle
• Hormone receptor down regulation: hormone secreted in large quantities cause down regulation of its target receptors
• Synergism: combined effects of two hormones amplified (glucagon with epinephrine work together to raise glucose levels)
• Antagonism: one hormone opposes other hormone (glucagon antagonizes insulin)

Question 30

What are examples of pituitary dysfunction?

Answer 30

● Tumour mass effects
● Hormone excess
● Hormone deficiency

Question 31

What hormones does the posterior pituitary release?

Answer 31

Oxytocin and ADH

Question 32

Describe the hypothalamo-pituitary-thyroid axis

Answer 32

Hypothalamus –> TRH –> anterior pituitary –> TSH –> thyroid gland –> thyroid hormones

Question 33

What are some functions of thyroid hormones?

Answer 33

● Accelerates food metabolism
● Increases protein synthesis
● Enhances fat metabolism
● Brain development during foetal life and postnatal development
● Growth rate accelerated

Question 34

What hormones does the anterior pituitary release?

Answer 34

TSH
ACTH
FSH & LH
GH
Prolactin

Question 35

What class of hormone does the adrenal cortex produce?

Answer 35

Steroids

Question 36

What types of hormones are produced in the adrenal cortex?

Answer 36

• Mineralocorticoids
  
  • aldosterone
• Glucocorticoids
  
  • cortisol androgens
• Androgens
  
  • androstenedione
  • dihydroepiandrosterone (DHEA)

Question 37

What hormones are produced in the adrenal medulla?

Answer 37

• Epinephrine
• Norepinephrine