Temperature control and hormones- Module 5

Question 1

what does vasodilation result in, why is this bad under cold conditions

Answer 1

-results in more blood nearer to the skin surface (due to increase in blood ammount, not the change in loacation)
-will lose more heat
-organs will not be able to maintain function

Question 2

where is aldosterone produced and what is its role

Answer 2

-in adrenal cortex

role:
-water reabsorption
-control of blood pressure
-ion concentration in blood/ reabsorption in kidneys

Question 3

why is it important that a patient had not eaten for at least 8 hours before a test measuring a ‘fasting blood glucose’ concentration

Answer 3

time is needed to restore normal glucose concentration for insulin to act (fully)

Question 4

why is standard deviation better than range for measuring the dispersion of data

Answer 4

-less affected by the anomaly/outlier
-takes into account every value in the data
-outliers can be calculated and rejected

Question 5

describe two aspects of the experimental design that scientists would need to consider in order to produce a valid comparison of the the patients
-one who had received stem cell therapy to treat diabetes
-one who hadn’t

Answer 5

-measure blood glucose by using same method
-measure blood glucose the same number of times
-medical history= age + gender
-using correct stats tests to compare

Question 6

basic description of how a beta cell secretes insulin in response to blood glucose concentration once glucose is in cell

Answer 6

1)Glucose transporter moves glucose into Beta cell
2)Glucose is metabolised to make ATP by mitochondria
3)ATP binds to KATP channel -> closes -> stops K+ leaving cell
4)membrane depolarises to -30mV
5)Voltage gated Ca2+ channel opens -> Ca2+ influx
6)ca2+ causes secretory vesicles containing insulin to move to and fuse with plasma membrane, releasing insulin via exocytosis

Question 7

Fter initial release of insulin from beta cell, insulin secretion continues even when there is no further glucose intake

explain and suggest why the cell continues to secrete insulin

Answer 7

-as long as blood glucose concentrations remain high
-ATP is still present and so K+ channels remain closed
-exocytosis is still being triggered by calcium ions

Question 8

describe how glucagon is involved in the regulation of blood glucose concentration (correctly functioning)

Answer 8

-released by alpha cells in islets of Langerhans
-promotes conversion of glycogen into glucose / glycogenolysis in liver/muscle
-ref to gluconeogenesis
-ref to conversion of triglycerides into fatty acids
-negative feedback reduces secretion of glucagon
-Glucagon reduces insulin reduction