Unit 1: Hormones and Transport

Question 1

What are endocrine cells

Answer 1

Glandular secretory cells that release their secretions into the extracellular fluid.

Question 2

What are exocrine cells

Answer 2

Cells which secrete their products onto epithelial surfaces, generally by way of ducts

Question 3

What are some similarities between the nervous and endocrine systems?

Answer 3

Both rely on release of chemicals that bind to specific receptors on target cells
Share chemical messengers e.g. norepinephrine and epinephrine
Both regulated mainly by negative feedback control mechanisms
Both used to maintain homeostasis

Question 4

What are some differences between the nervous and endocrine systems?

Answer 4

NS: Neurones use action potentials and neurotransmitters to control specific cells
Only a small fraction of cells are innervated
Commands are very specific and short-lived
ES: Hormones produced by endocrine cells reach almost every cell in the body
Effects of hormone on target cell may be slow to appear but can last for days

Question 5

What are the major processes affected bu hormone actions

Answer 5

Growth and development
Reproduction
Regulation of cell metabolism and energy balance
Regulation of body water content and levels of electrolytes and organic nutrients
Mobilisation of body defences.

Question 6

What does the endocrine system include?

Answer 6

All endocrine cells and tissues that produce hormones or paracrines with effects beyond their tissues of origin.

Question 7

What are the 3 classes of hormones?

Answer 7

1. amino acid derivatives
2. peptide hormones
3. lipid derivatives

Question 8

What are amino acid derivatives synthesised from?

Answer 8

Tyrosine
Tryptophan

Question 9

What are primary endocrine glands and give examples.

Answer 9

Glands which their main role is to secrete hormones
e.g. Hypothalamus, pituitary gland, pineal gland, thyroid gland, supernal glands and parathyroid glands pancreas, gonads

Question 10

What are secondary endocrine glands and give examples

Answer 10

primary role is something else in the body but secondary role is to secrete hormones
E.g. organs such as heart, kidney, liver, skin

Question 11

What are the 4 intracellular communications by the Endocrine system?

Answer 11

1. Direct
2. Paracrine
3. Autocrine
4. Endocrine

Question 12

direct

Question 13

paracrine

Question 14

autocrine

Question 15

endocrine

Question 16

What gland secretes melatonin

Answer 16

Pineal gland

Question 17

What are some similarities and differences between hormones derived from tyrosine and tryptophan?

Answer 17

Tyrosine: hydrophilic, transported in secretary vesicles in blood, short half life (5-10 mins)
Tryptophan: lipophilic, transported bound to plasma proteins, long half lives (days)

Question 18

What hormones are made from tyrosine?

Answer 18

Thyroid hormones (T4, T3)
Catecholamines (adrenaline, noradrenaline, epinephrine, norepinephrine, dopamine)

Question 19

What hormones are made from tryptophan?

Answer 19

Melatonin

Question 20

What are the 2 groups peptide hormones are divided into?

Answer 20

1. Glycoproteins
   Inhibin, FSH, LH, TSH, EPO
2. Short polypeptides and small proteins
   ADH, oxytocin, MSH, GH, prolactin, ANP, BNP. lectin

Question 21

What are the 2 groups of lipid derivatives?

Answer 21

1. Eicosanoids: derivative of arachidonic acids
2. Steroids: structurally similar to cholestrol

Question 22

Examples of Eicosanoid hormones

Answer 22

Leukotrienes, prostaglandins, thromboxane, prostacyclins

Question 23

Examples of steroid hormones

Answer 23

androgens, oestrogen, progestins, mineralocorticoids, calcitriol

Question 24

What are steroid hormones synthesised from?

Answer 24

Cholestrol

Question 25

Properties of steroid hormones

Answer 25

Lipid soluble (crosses membrane easily)
Not stored in vesicles
Effective at low free conc due to high receptor affinity
Secreted as they are produced

Question 26

What hormones does the hypothalamus produce?

Answer 26

ADH, OXT and regulatory hormones

Question 27

What hormones does the anterior and posterior pituitary gland produce?

Answer 27

Anterior: ACTHM TSH, GH, PRL, LH, MSH
Posterior: Oxytocin (OXT) and ADH

Question 28

What hormones does the thyroid gland produce?

Answer 28

T4, T3, calcitonin

Question 29

What hormones does the adrenal glands produce?

Answer 29

Medulla: Epinephrine, Norepinephrine
Cortex: Cortisol, corticosterone, cortisone, aldosterone, androgens

Question 30

What hormones does the pancreas produce?

Answer 30

Beta cells: Insulin
Alpha cells: Glucagon

Question 31

What hormones does the pineal gland produce?

Answer 31

Melatonin

Question 32

What hormones does the Parathyroid glands produce?

Answer 32

PTH (parathyroid hormone)
Parathyroid glands located on the posterior surfaces of the thyroid gland.

Question 33

Organs with secondary endocrine functions

Answer 33

Heart: ANP, BNP
Thymus: Thymosins
Adipose tissue: Leptin
Digestive tract:
Kidneys: EPO, calcitriol
Gonads:
Testes - androgens and inhibin
Ovaries - estrogens, progesterone, inhibin

Question 34

How are freely circulating hormones inactivated?

Answer 34

When it diffuses out of the bloodstream and binds to receptors on target cells
Its absorbed and broken down by cells of the liver or kidney
Its broken down by enzymes in the blood or interstitial fluid.