Endocrine

Question 1

At what temperature does hyperthermia become lethal and start damaging nerves and affecting enzymes?

Answer 1

41oC; death occurs at 43.3oC

Question 2

How does the volume of the core vary depending on temperature?

Answer 2

It expands when the body heats up and shrinks when it’s cold

Question 3

What type of heat production is most prevalent in humans?

Answer 3

Convection: the transfer of heat by the movement of air or liquid passing by the body

Question 4

Define ‘allostasis’

Answer 4

The anticipation of temperature (e.g. looking at the weather and deciding what clothing to wear)

Question 5

What are the 3 classes of hormones and name an example of each?

Answer 5

1. Protein/ peptide: insulin, glucagon, growth hormone, ACTH
2. Steroid: cortisol, aldosterone, oestrogen, VitD
3. Amino-acid dervived: norepinephrine, epinephrine, dopamine

Question 6

What amino acid are amino-acid derived hormones made from?

Answer 6

Tyrosine

Question 7

What are steroid hormones derived from?

Answer 7

Cholesterol

Question 8

What type of hormones are metabolised by the liver?

Answer 8

Freely transported hydrophilic hormones (amines, proteins, peptides)

Question 9

Define ‘half-life’ of a substance’

Answer 9

The time in which the concentration of the substances reduces to 50% of the original

Question 10

List the 4 hormone types (peptides, thyroid, steroids and amines) in increasing order of half life

Answer 10

Amines (2-3mims)
Peptides (4-40mins)
Steroids (4-170mins)
Thyroid hormones (0.75-6.7days)

Question 11

Define ‘affinity’

Answer 11

A measure of the rate of association and dissociation for a hormone-receptor complex. As hormones circulate at low concentrations , affinity levels must be high to have the intended outcome.

Question 12

What cycle breaks down pyruvate from glycolysis?

Answer 12

The TCAcycle

Question 13

Define ‘gluconeogenesis’

Answer 13

The synthesis of glucose from a non-carbohydrate source (e.g. lactate, glycerol). It occurs in the liver but can also happen in the kidneys after prolonged starvation.

Question 14

What cells in the pancreas produce the following: glucagon, insulin and somatostatin?

Answer 14

Alpha cells = glucagon
Beta cells = insulin
Delta cells = somatostatin

Question 15

List the events involved in stimulus-secretion coupling for the release of insulin.

Answer 15

1. Glucose is transported into the cell
2. Glucose is converted into G6P by GK, followed by metabolism
3. ATP/ADP production increases
4. K-ATP pump is inhibited from pumping K+ out of the cell
5. Stimulates the L-Ca2+ pump to bring Ca2+ into the cell
6. Insulin released from cell

Question 16

What is the most common type of diabetes

Answer 16

Type 2 with 90% of patients being diagnosed with this type

Question 17

What is the underlying mechanism of Type 1 diabetes?

Answer 17

This involves a type IV hypersensitivity cell mediated response in where the body’s T-cells attack its own pancreas resulting in the body unable to produce enough insulin.

Question 18

What genetic mutation is associated with Tyoe 1 diabetes?

Answer 18

A genetic mutation in the Human Leukocytes Antigen (HLA) which is a group of genes on chromosome 6 usually responsible for encoding the major histocompatibility complex (MHC) - important for cellular self-recognition = self-tolerance

Question 19

Name the 4 major symptoms of Type 1 diabetes.

Answer 19

Polyphagia, glycosuria, polyuria and polydipsia.

Question 20

Describe ‘Diabetic Ketoacidosis (DKA).

Answer 20

When there is a lack of glucose and the body is forced to break down adipocytes for energy into free fatty acids. These fatty acids are then broken down by the liver into ketone bodies which contain the ketoacid chemical group. This raises the acidity of blood which can be very dangerous for the body

Question 21

Describe the underlying mechanism of Type 2 diabetes.

Answer 21

This condition does not involved abnormal production of insulin but instead the body cannot respond to insulin as cells become insulin-resistant. The exact mechanism is not fully understood but it thought to have links with chemicals released by adipocytes increeasing inflammation and then in turn increasing chance of insulin-resistance.

Question 22

Describe hyaline arteriosclerosis.

Answer 22

Protein hyaline deposits form on the walls of the arterioles that can cause them to become hard and inflexible; impairs blood flow

Question 23

What is the difference between ultradian and infradian cycles?

Answer 23

Ultradian cycles are ones that last less than a day whereas infradian cycles last longer than a day

Question 24

What is a ‘Zeitberger’ and name some examples.

Answer 24

This is a German word used to describe factors (I.e. “time-givers”) that affect our daily cycle: meals, temperature, social activity, the tide.

Question 25

What is the urinary system derived from in the developing embryo?

Answer 25

The intermediate mesoderm

Question 26

What are the 3 pairs of chronological kidneys that form in the urinary tract production?

Answer 26

Pronephron, mesonephron and metanephron

Question 27

What vessel is most common to cause a horse-shoe kidney deformation?

Answer 27

The inferior mesenteric artery

Question 28

What gene is affected in autosomal dominant polycyclic kidney disease (ADPKD)?

Answer 28

The polycystic gene

Question 29

What gene is affected in autosomal recessive polycystic kidney disease (ARPKD).

Answer 29

The polyductin gene

Question 30

Where are carotid baroreceptors located?

Answer 30

Located in the carotid sinus at the branch of the carotid artery

Question 31

What are the 2 main goals of the Bainbridge reflex?

Answer 31

Atrial volume receptors located in the veins and atria aim to:

1. Reduce damming of blood in the atria and vein
2. Avoid overloading the lungs with blood

Question 32

How much blood does each kidney receive every minute?

Answer 32

1200ml

Question 33

What maintains the constant pressure of renal blood flow?

Answer 33

The juxta-glomerular apparatus

Question 34

What is the main goal of the use of diuretics?

Answer 34

To increase urine production which, in turn reduces both blood volume and blood pressure

Question 35

What are the 3 main processes involved in urine production?

Answer 35

1. Glomerular filtration
2. Tubular selective reabsorption (glucose,aa, Na+, Cl-etc.)
3. Tubular secretion (drugs, H+ ions)