Adrenal medulla & adrenaline

Question 1

what is the stress response?

Answer 1

process that is initiated by events that threaten/harm/challenge an organism, there are two types of response.

Question 2

What are the two types of responses of the stress axis?

Answer 2

Acute (Rapid response) and Chronic (long term)

Question 3

Describe the Acute (rapid response)

Answer 3

• sympathetic nervous system mediated release of adrenaline and noradrenaline from the adrenal medulla

Question 4

Describe the Chronic (long term response)

Answer 4

-hypothalamic-pituitary-adrenal Axis (HPA) mediated release of steroid (predominantly glucocorticoids)

Question 5

Describe the adrenal glands:

Answer 5

small glands
4-6g in mass
triangular positioned
bilaterally positioned on the superior poles of the kidney
two main areas: 
inner - MEDULLA
outer - CORTEX

Question 6

Describe the glomerulosa

Answer 6

lies under fibrous capsule
5-10% of cortex
cells closely packed in clumps

Question 7

Describe the fasciculata

Answer 7

Lies under ZG
75% of cortex volume
larger cells than ZG arranged radially in cords separated by cortical capillaries

Question 8

Describe the reticularis

Answer 8

network of interdigitating capillaries

Question 9

What cells is the adrenal medulla composed of?

Answer 9

chromaffin cells

Question 10

Describe the chromaffin cells of adrenal medulla

Answer 10

electron dense granules store molecules secreted by the cell

Question 11

What is synthesised and released by chromaffin cells?

Answer 11

Catecholamines, adrenaline and noradrenaline

also produce opioid peptides

Question 12

Whats the blood supply like to the adrenal glands>

Answer 12

from superior, inferior and middle adrenal arteries

Question 13

medulla is what of origin?

Answer 13

neurodermal

Question 14

the cortex is what of origin?

Answer 14

Mesodermal

Question 15

What % is adrenaline of the total catecholamines produced?

Answer 15

80%

Question 16

What % is noradrenaline of the total catecholamines produced?

Answer 16

20%

Question 17

what is each chromatin cell innervated by?

Answer 17

pre-ganglionic sympathetic neurone T5-11

Question 18

fibers in cortex interface mainly with what?

Answer 18

blood vessels, no secretomotor innervation

Question 19

The synthesis of noradrenaline and adrenaline is regulated by what?

Answer 19

negative feedback; tyrosine hydroxyls is -vely regulated by dopamine and noradrenaline

Question 20

why are the short term effects of epinephrine and norepinephrine?

Answer 20

1. glycogen broken down into glucose
2. Increased blood pressure
3. Increased breathing rate
4. Increased metabolic rate
5. Change in blood flow patterns, leading to increased alertness and decreased digestive and kidney activity

Question 21

what are the long term effects of mineralocorticoids?

Answer 21

1. Retention of sodium ions and water by kidneys

2. Increased blood volume and blood pressure

Question 22

What are the long term effects of glucocorticoids?

Answer 22

1. Proteins and fats broken down and converted to glucose, leading to increased blood glucose
2. Immune system maybe suppressed

Question 23

what is a Pheochromocytoma?

Answer 23

tumour of adrenal medulla

Question 24

What are the symptoms of pheochromocytoma?

Answer 24

episodic hypertension due to excessive secretion of adrenaline and noradrenaline

Question 25

What is the treatment of pheochromocytoma?

Answer 25

alpha and beta adrenoreceptor blockers

tumour removal