The Endocrine System

Question 1

What is the role of glucose?

Answer 1

Essential for cellular resperiation
Broken down to release energy
Energy released used to make ATP from ADP and inorganic phosphate

Question 2

What is glycogen

Answer 2

Large storage molecule synthesised from glucose in animals, fungi , bacteria

Question 3

Where is glycogen stored?

Answer 3

MuscProcess Description When it occurs

Glycogenesis - Glycogen is made from glucose - After meals

Glycogenolysis -Glycogen is broken down to release glucose- Between mealsles (80%) and Liver (20%)

Question 4

What is Gluconeogenesis?

Answer 4

A metabolic pathway used to keep blood glucose level within tolerance limits

Glycerol / amino acids Glucose

Question 5

Regulation of blood glucose

Answer 5

Tightly regulated to keep Glucose Concentration within tolerance range

· Deviations outside tolerance range detected by specialised cells in PANCREAS

· Pancreas secretes hormones Glucagon and Insulin to regulate blood glucose level

Question 6

How do Insulin and Glucagon maintain blood glucose within tolerance limits?

Answer 6

by NEGATIVE FEEDBACK

· Increase/decrease of glucose outside tolerance limit in blood is detected by receptors in Pancreas

· Receptors respond by releasing Insulin or glucagon into the blood to initiate a corrective mechanism that restores the blood glucose level to within normal range

Question 7

What is Diabetes Mellitus?

Answer 7

= A group of disorders that are linked to HIGH blood glucose levels

Occurs when individuals have reduced Insulin secretion which results in the concentration of blood glucose frequently exceeding the tolerance range.

Symptoms

· Increased blood glucose above tolerance

· Increased glucose in urine

· Excess urination

· Excessive thirst

· Excessive eating caused by loss of glucose

Question 8

Types of Diabetes

Answer 8

Type I Beta cells in pancreas are destroyed by immune system

Less insulin produced and released

Type II Body cells become resistant to effects of insulin

Prevents transport of glucose into cells for respiration

Levels of glucose rise

Gestational Body cells have reduced response to insulin during pregnancy

Treatment

Type 1 Injections of Insulin

i basal insulin injection once day results in absorption of glucose slowly across day

ii bolus insulin injections at meal time

Type 2 Change of diet, exercise medications and insulin therapy

Question 9

Describe the action of thyroid stimulating hormone and thyroxine in metabolism.

Question 10

What is the Hypothalamus?

Answer 10

= bridge between the nervous system and endocrine system

Part of CNS

Receives and sends out nerve impulses

Secretes hormones and hormone like substances that control the release of hormones by the pituitary

Question 11

What is metabolism?

Answer 11

Metabolism = the sum of all of the reactions occurring within cells in the body of an organism

Hi metabolic rate increases body temperature

Low metabolic rate reduces body temperature

Question 12

What occurs when the body temp falls outside the tolerance range?

Answer 12

Fall in body temperature below acceptable limit:

· Detected by Thermoregulatory centre in Hypothalamus

· Hypothalamus releases TRH (Thyroid releasing hormone) which travels to Pituitary gland

· TRH stimulates the pituitary gland to release TSH (Thyroid stimulating hormone)

· TSH travels in blood to thyroid gland and stimulates the release of thyroxine

· Thyroxine travels to cells via blood and stimulates an increase in their metabolic rate.

· Increased metabolism increases heat production

· Increased heat production causes an increase in temperature

Question 13

Rise in body above acceptable limits

Answer 13

· Detected by Thermoregulatory centre in Hypothalamus

· Results in reduced release of TRH by the hypothalamus

· Results in reduced levels of TSH being released by anterior pituitary gland

· Results in reduced release of thyroxine from the thyroid gland

· Results in reduce metabolism by cells

· Decreased cell metabolism decreases heat production

· Decreased heat production causes a decrease in temperature.

Question 14

Describe the role of adrenaline in the ‘fight or flight’ response.

Answer 14

Information from sensory receptors is relayed to the regions of CNS associated with perception of fear.(AMYGDALA)

· Amygdala sends nerve impulses to HYPOTHALAMUS in brain which relays nerve impulse to ADRENAL GLAND.

· ADRENAL GLAND secretes ADRENALINE into blood.

· ADRENALINE prepares the body for fight or fright by acting on a wide variety of structures including smooth muscle, cardiac muscle brain and pancreas

Question 15

You must be able to Explain how the nervous and endocrine systems work independently or together to enable osmoregulation.

Question 16

ADH and osmolarity of a high osmolarity

Answer 16

A decrease in water concentration (high osmolarity) is detected by osmoreceptors in the hypothalamus .This stimulates the release of ADH into the circulatory system. ADH is transported to the kidneys where it increases the permeability of the distal convoluted tubule and collecting duct. Water diffuses into the blood from the filtrate which decreases osmolarity and reduces the volume of water excreted in urine. The decrease in osmolarity of the blood inhibits further production and secretion of ADH.