Learning Topics - 7.01 and 7.02

Question 1

Catecholamines

Answer 1

Dopamine, adrenaline, noradrenalin

Question 2

Phaeochromocytoma

Answer 2

Tumour of the adrenal medulla

Question 3

Effect of SNS stimulation on glucose production

Answer 3

Increased glycogenolysis, gluconeogenesis, increased hepatic glucose output. Overall, increased glucose available for muscle action

Question 4

Effect of SNS stimulation on triglyceride production

Answer 4

Increased breakdown, increased output of lipoproteins containing triglycerides

Question 5

Effect of increased cortisol production on end organs

Answer 5

Immune suppression

Question 6

Effects of vasoconstriction on kidneys

Answer 6

Decreased renal blood flow –> increased RAAS activation –> increased vasopressin –> increased blood volume –> increased blood pressure

Question 7

What vasodilates and what vasoconstricts upon sympathetic activation?

Answer 7

Vessels to skin, gut, other organs including kidneys vasoconstrict.

Vessels to skeletal muscle and lungs dilate

NB the overall effect is to increase BP

Question 8

What effect does SNS activation have on the heart?

Answer 8

Increased heart rate and contractility. Overall effect is to increase BP

Question 9

In what endocrine diseases might anxiety be the presenting feature?

Answer 9

Phaeochromocytoma, thyrotoxicosis (diseases associated with excess catecholamine activity)

Question 10

BMR

Answer 10

Basal Metabolic Rate

Question 11

Define BMR

Answer 11

Energy expended when completely at rest, but not asleep and in the absence of:

• muscle movement
• sympathetic arousal

Question 12

RMR

Answer 12

Resting Metabolic Rate. About 10-15% higher than BMR.

Question 13

Measurement of RMR

Answer 13

Indirect calorimetry and direct calorimetry

Question 14

Indirect calorimetry

Answer 14

Measures O2:CO2 in fasted state using ventilated hood

Question 15

Direct calorimetry

Answer 15

Measured using a metabolic chamber

Question 16

What units are BMR/RMR measured in?

Answer 16

Kilocalories/24 hours

Adjusted for fat-free mass (“lean body mass”)

Question 17

Lean body mass

Answer 17

Metabolically active tissue

Question 18

BMR is “the idling rate of the body engine”. What are the additional components of energy expenditure?

Answer 18

• thermoregulatory heat
• TEE (thermic effect of exercise)
• TEF (thermic effect of food)

Question 19

What is TEE?

Answer 19

Thermic effect of exercise

Energy required for muscle activity + energy lost as heat to maintain core temperature by elimination

Question 20

What is TEF?

Answer 20

Thermic effect of food

Energy required for the absorption and processing of food + facultative energy loss (??)

Question 21

What increases BMR?

Answer 21

Increased sympathetic activity

Pharmaceuticals (caffeine, amphetamines)

Question 22

What decreases BMR?

Answer 22

Fasting, calorie restriction, weight loss, hypothermia

Question 23

What are two forms of energy expenditure in humans?

Answer 23

BMR

Thermoregulation

Question 24

Thermoregulation

Answer 24

The maintenance of core body temperature.

May involve gain or loss of heat.

Question 25

2 mechanisms which cause gain of body heat

Answer 25

Shivering thermogenesis

Non-shivering thermogenesis

Question 26

Shivering thermogenesis

Answer 26

Muscle contraction

Superficial circulatory vasoconstriction (decreases amount of heat lost to atmosphere)

Question 27

Non-shivering thermogenesis

Answer 27

The production of ADDITIONAL HEAT via biochemical reactions in skeletal muscle.

Question 28

Hyperthermia in the absence of increased temperature exposure is due to ….

Answer 28

CNS lesions (?!)

Question 29

Hypothermia in the absence of cold exposure is due to …

Answer 29

Illnesses associated with severe metabolic acidosis (?)

Hypothyroidism

Question 30

Adrenaline is secreted by

Answer 30

Adrenal medulla

Question 31

Dopamine is secreted in the CNS as …

Answer 31

A neurotransmitter (mesocortical and mesolimbic pathways)