Intro

Question 1

What are hormones

Answer 1

Chemical messengers

Question 2

Where are hormones secreted into

Answer 2

Directly into bloodstream

Question 3

What are endocrine glands

Answer 3

They are ductless with rich blood supply. They typically act on tissues distant from source

Question 4

What are exocrine glands

Answer 4

They may or may not have excretory ducts. They release secretions onto epithelial surface

Question 5

What are the 3 main types of hormones

Answer 5

Proteins, steroids and amino acid derivatives

Question 6

What are steroids synthesised from

Answer 6

Cholesterol

Question 7

What are amino acid derivatives modified from

Answer 7

Tyrosine

Question 8

What does an episodic hormone respond to

Answer 8

In response to physiological demand

Question 9

What is a diurnal hormone

Answer 9

Predictable pattern over 24hr

Question 10

What is a constant hormone

Answer 10

Fairly constant blood concentrations for normal physiological function

Question 11

What are the 3 types of stimuli that trigger endocrine glands

Answer 11

Humoral, neuronal and hormonal

Question 12

What is humoral stimuli

Answer 12

Circulating molecules in the blood

Question 13

What is neuronal stimuli

Answer 13

Stress response - SNS

Question 14

What is hormonal stimuli

Answer 14

In response to hormones produced by other endocrine glands

Question 15

What endocrine glands coordinate the endocrine system

Answer 15

Hypothalamus and pituitary gland

Question 16

What does the hypothalamus do

Answer 16

• Controls release of hormones from the anterior lobe of the pituitary gland
• Also synthesises hormones (oxytocin and antidiuretic hormone) which are stored in the posterior lobe of the pituitary gland

Question 17

What are the 2 major lobes of the pituitary gland

Answer 17

• Anterior pituitary = adenohypophysis
• Posterior pituitary = neurohypophysis

Question 18

What is the adenohypophysis

Answer 18

• Oral ectoderm derived
• Vascular connection to hypothalamus

Question 19

What is the neurohypophysis

Answer 19

• Neuroectoderm derived
• Direct neural link to hypothalamus

Question 20

Where are the lobes located

Answer 20

Located in a hollow of the sphenoid bone

Question 21

What does the adenohypophysis consist of

Answer 21

Epithelial cells

Question 22

What does the adenohypophysis secrete

Answer 22

• Growth Hormone (GH)
• Thyroid stimulating hormone (TSH)
• Adrenocorticotropic hormone (ACTH)
• Follicle stimulating hormone (FSH)
• Luteinising hormone (LH)
• Prolactin

Question 23

What does the neurohypophysis consist of

Answer 23

Neural tissue

Question 24

What does the neurohypophysis store

Answer 24

Hormones secreted by neurosecretory cells in the hypothalamus

Question 25

How are the stored hormones transported

Answer 25

Via neuronal axons to the posterior lobe

Question 26

What are the 2 hormones stored

Answer 26

- Anti-diuretic hormone (ADH) or Vasopressin -Oxytocin

Question 27

What does the thyroid gland consist of

Answer 27

Two lobes covering the anterolateral surface of the trachea

Question 28

Where is the thyroid gland

Answer 28

Within the visceral compartment of the neck surrounded by the pretracheal fascia

Question 29

How does the thyroid develop in the embryo

Answer 29

As a down growth of the tongue epithelium

Question 30

Where is thyroglobulin synthesised

Answer 30

In follicular cells – stored in the follicle lumen

Question 31

How does thyroglobulin generate hormones

Answer 31

Thyroglobulin combines with iodine and endocytosed back into the follicular cells and cleaved to generate Thyroid hormone: - Tri-iodothyronine (T3) - Thyroxine (T4)

Question 32

What does thyroxine regulate

Answer 32

- Rate of metabolism – energy use - Protein production – growth & development - Sensitivity of cells to other hormones

Question 33

What is the parathyroid gland

Answer 33

Two pairs of glands embedded in the posterior aspect of the thyroid gland

Question 34

Where does the parathyroid gland develop from

Answer 34

The wall of the pharynx

Question 35

What does parathyroid hormone do

Answer 35

- Regulates calcium homeostasis – stimulates osteoclasts to breakdown bone matrix and increase blood Ca++ levels - Promotes conversion of inactive vitamin D to active form (vit D required for absorption of Ca++ from diet)

Question 36

What are the adrenal glands

Answer 36

Paired glands situated superior to the kidneys

Question 37

What are adrenal glands comprised of

Answer 37

- Cortex – glandular tissue derived from the mesoderm - Medulla – sympathetic nervous system derived from the neural crest (neuroectoderm)

Question 38

What does the adrenal cortex produce

Answer 38

Steroid hormones called corticosteroids - cholesterol is the common precursor

Question 39

What are the steroid hormones produced by the adrenal complex

Answer 39

- Zona glomerulosa - Mineralocorticoids – e.g. Aldosterone - Zona fasciculata - Glucocorticoids – e.g. Cortisol - Zona reticularis - sex steroids

Question 40

What is the cortisal feedback mechanism

Answer 40

Stimulated by stress – exercise and hypoglycaemia Clear diurnal rhythm of activity: - Peaks: 6 – 8 am - Lowest: midnight – 2 am Main effects: - Glucose mobilisation - Cardiovascular (blood volume) - Sensitivity to catecholamines

Question 41

What is the adrenal medulla

Answer 41

Direct connection with the sympathetic nervous system – primed for immediate response – fight or flight

Question 42

What is the adrenal medulla the site of

Answer 42

Catecholamine synthesis and secretion

Question 43

What do chromaffin cells produce

Answer 43

- Epinephrine - Norepinephrine - Dopamine

Question 44

What do islets of Langerhans produce

Answer 44

- Glucagon in alpha cells - Insulin in beta cells