lecture 28 - cortisol & stress

Question 1

Where is cortisol produced?

Answer 1

The adrenal cortex

Question 2

What carrier protein is cortisol bound to during transport through the blood stream?

Answer 2

Corticosteroid binding hormone

Question 3

What type of target cell receptors does cortisol bind to?

Answer 3

Intracellular (cytoplasmic or nuclear) receptors

Question 4

What is the process of cortisol target cell binding?

Answer 4

Cortisol diffuses through cell membrane, binds to intracellular receptor to form complex, complex binds to specific region of DNA activating genes which are transcripted to mRNA then translated to make proteins.

Question 5

What stimulus is cortisol released in response to?

Answer 5

Stress

Question 6

What are neural inputs that result in the secretion of cortisol, aside from stress?

Answer 6

Day-night rhythm, low blood glucose concentration.

Question 7

What effect does cortisol have on blood glucose levels?

Answer 7

Increases them

Question 8

What effect does cortisol have on metabolism of fat, protein and carbohydrates?

Answer 8

Increased metabolism to maintain blood glucose

Question 9

Are anti-inflammatory actions promoted or inhibited by cortisol?

Answer 9

Promoted

Question 10

What effect does cortisol have on blood pressure?

Answer 10

Increases it

Question 11

What effect does cortisol have on the heart and blood vessels?

Answer 11

Increased heart and blood vessel tone and contraction.

Question 12

What effect does cortisol have on the immune system, in the long term?

Answer 12

Suppresses the immune system

Question 13

When, over the course of the day, are cortisol levels highest?

Answer 13

After waking in the morning

Question 14

What is hyposecretion?

Answer 14

When too little hormone is released

Question 15

What is hypersecretion?

Answer 15

When too much hormone is secreted

Question 16

What are common causes of hormone signalling problems? (3)

Answer 16

Autoimmunity, genetic mutation, tumors

Question 17

How does autoimmunity cause hormone signalling problems?

Answer 17

Receptors are destroyed, or they may be artificially stimulated

Question 18

How do tumours cause hormone signalling problems?

Answer 18

Excess tissue may cause excess release of hormone, or may inhibit release

Question 19

What is Addison’s Disease?

Answer 19

A condition that occurs when there is insufficient secretion of cortisol and aldosterone from the adrenal cortex.

Question 20

Why do patients with Addison’s disease often have elevated ACTH levels?

Answer 20

Adrenocorticotropic hormone is released due to low cortisol levels, in a negative feedback loop.

Question 21

Why do patients with Addison’s disease often have darkened patches of skin?

Answer 21

Increased ACTH levels stimulates melanin synthesis in the skin.

Question 22

What is Cushing’s disease

Answer 22

A condition caused by the secretion of too much cortisol.

Question 23

What are the symptoms of Addison’s disease?

Answer 23

Low blood pressure, weakness, hyperpigmentation of skin

Question 24

What are the symptoms of Cushing’s disease?

Answer 24

High blood pressure, weakness/muscle wasting, tumours, fat deposits

Question 25

What does stress activate?

Answer 25

The hypothalamus

Question 26

In response to stress, what anterior pituitary stimulating hormone is released by the hypothalamus?

Answer 26

CRH (corticotropin releasing hormone)

Question 27

What does CRH trigger the release of, and in which gland, in response to stress?

Answer 27

Adrenocorticotropic hormone (ACTH) in the anterior pituitary

Question 28

What hormone is secreted by the posterior pituitary in response to stress induced stimulus from the hypothalamus?

Answer 28

ADH - anti-diuretic hormone

Question 29

What three hormone pathways are activated by the hypothalamus in response to stressful stimulus?

Answer 29

Adrenal cortex releases cortisol, posterior pituitary release ADH, adrenal medulla (via sympathetic nervous system) releases adrenaline

Question 30

What is the ‘alarm phase’ of the body under stress?

Answer 30

A phase of immediate, short-term responses to stress/crisis, as a result of sympathetic stimulation and the release of adrenaline from the adrenal medulla

Question 31

What visceral reflexes are activated during the ‘alarms phase’ of stress?

Answer 31

Cardioaccelatory, vasomotor, pupillary light reflexes

Question 32

What is the cardioaccelatory reflex?

Answer 32

Increase in heart rate and force of heart contraction

Question 33

What are vasomotor reflexes, in the context of the alarm phase of stress?

Answer 33

Changes in diameter of peripheral vessels

Question 34

What is the pupillary light reflex?

Answer 34

Reflex that changes the diameter of the pupils in response to light.

Question 35

How is the pupillary light reflex activated in response to sympathetic nervous system stimulation?

Answer 35

The dilator pupillae muscles of the eye contract to increase pupil diameter

Question 36

What are some immediate short-terms responses (alarm phase) in response to stress?

Answer 36

Mobilisation of glycogen and lipid reserves, increased energy use by cells, mental alertness,, increased sweat gland secretion, increased heart rate

Question 37

What is the resistance phase of stress?

Answer 37

Long term effects and changes within the body due to prolonged exposure to stress.

Question 38

What are some long-term metabolic adjustments made during the resistance phase?

Answer 38

Mobilisation of lipid and amino acid reserves, conservation of glucose as glycogen by peripheral tissues (lipids used for energy instead), increased blood glucose concentration as liver synthesises glucose

Question 39

What hormone is released by the hypothalamus to trigger cortisol secretion?

Answer 39

Corticotropin releasing hormone