Endocrine and Metabolism - Tutorial 5

Question 1

State five ways that the endocrine system maintains homeostasis (affects body tissues)

Answer 1

• Altering metabolism
• Regulating growth and development
• Regulating reproduction
• Regulate circadian rhythms
• Regulate activity of smooth muscle, cardiac muscles and glands

Question 2

Explain why water soluble hormones cannot be administered via the oral route

Answer 2

Water soluble hormones are destroyed by digestion so insulin cannot be taken orally but must be injected

Question 3

Name the organ that has both endocrine & exocrine functions

Answer 3

Pancreas

Question 4

Explain how hormones are inactivated and excreted from the body.

Answer 4

Most hormones are inactivated by the liver and excreted by the kidneys or in the faeces

Question 5

Describe the three stimuli that trigger hormone secretion

Answer 5

Signals from the nervous system
- Sympathetic nervous system sends impulses to stimulate the adrenal medulla to release adrenaline (epinephrine)

The levels of a chemical in the blood
- Some endocrine glands secrete their hormones in direct response to changing levels of critical ions and nutrients

Another hormone
-Many endocrine glands are themselves stimulated by hormones

Question 6

Describe the structure and location of the pituitary gland

Answer 6

Small gland that lies in a hollow of the sphenoid bone

Question 7

Name the two hormones released from the posterior pituitary and state where they
are produced

Answer 7

Oxytocin and Antidiuretic hormone (ADH), is produced in the hypothalamus

Question 8

Name the six hormones produced by the anterior pituitary

Answer 8

• Growth hormone, GH
• Thyroid stimulating hormone, TSH
• Adrenocorticotropic hormone, ACTH
• Follicle stimulating hormone, FSH
• Luteinizing hormone, LH
• Prolactin

Question 9

Describe three clinical situations that arise from alterations to secretion of Growth Hormone (GH)

Answer 9

Dwarfism - hyposecretion during growth years results in dwarfism

Giantism - hypersecretion in childhood results in giantism

Acromegaly - Hypersecretion in adulthood results in acromegaly

Question 10

State the location of the adrenal glands

Answer 10

Located at the top of the kidneys

Question 11

Name the two areas within each gland and what hormones are produced by each of these areas

Answer 11

• Adrenal cortex that secretes cortisol and aldosterone
• Adrenal medulla that secretes adrenalin and noradrenaline

Question 12

State a clinical situation where glucocorticoids (cortisol) might be prescribed

Answer 12

• Cortisol medications are often prescribed to suppress the inflammatory response in chronic conditions and are prescribed for organ transplant patients to avoid organ rejection

Question 13

State six effects/actions of adrenaline

Answer 13

• Increases rate and force of heart contraction
• Increases cardiac output
• Increase blood pressure
• Increase blood flow to the myocardium, liver, skeletal muscles

Question 13

Name the two hormones that control blood calcium levels

Answer 13

• Parathyroid hormone (PTH) is the main hormone which increases blood calcium level
• Calcitonin is the hormone which decreases blood calcium levels

Question 14

State three uses for calcium in the body

Answer 14

• Transmission of nerve impulses
• Muscle contraction
• Blood clotting

Question 15

Describe three actions of PTH

Answer 15

• Stimulates osteoclasts to resorb bone and raise blood calcium
• Enhances reabsorption of calcium by the kidneys
• Activates vitamin D to become calcitriol which is needed to absorb calcium from food

Question 16

Name the hormone that is produced from the pineal gland

Answer 16

Melatonin

Question 17

Describe the location of pineal gland

Answer 17

Is attached to the roof of the 3rd ventricle

Question 18

Name the three stages of the stress response

Answer 18

1. An initial fight or flight response
2. A slower resistance reaction
3. Exhaustion

Question 19

Name two health implications of stress

Answer 19

Stressors - heat, cold, environmental poisons, bacterial toxins, heavy bleeding or a strong emotional reaction

Homeostatic mechanisms - attempt to counteract stress it is controlled by the hypothalamus in three stages:
1. An initial fight or flight response
2. A slower resistance reaction
3.Exhaustion

Question 20

Describe four age related changes to the endocrine system

Answer 20

• Growth hormone decreases allowing muscle atrophy
• Thyroid gland decreases production of thyroid hormones - decrease in metabolic rate, increase in body fat
• Pancreas releases insulin more slowly and cells are not as responsive to insulin (insulin resistance)
• Ovaries become unresponsive to FSH and LH so decrease oestrogen production - osteoporosis, high blood cholesterol and atherosclerosis
• Testosterone levels decline but effects aren’t apparent until old age

Question 21

Define the terms anabolism & catabolism

Answer 21

• Anabolism: is the building of complex molecules from numerous simple one.
• Catabolism: is the breakdown of complex molecules into numerous simple ones.

Question 22

Name the two products resulting from lipolysis & what they are used for

Answer 22

• Glycerol and Fatty Acids
• Glycerol - converted into pyruvate (pyruvic acid) and enters the kerbs cycle to produce ATP, can also be converted to glucose by gluconeogenesis

Fatty acids - converted into acetyl coenzyme A (CoA) in the liver, then enters kerbs cycle to produce ATP, if CoA levels are to high for the Krebs cycle to process the liver will converts CoA to ketone bodies

Question 23

Describe what causes an increase in ketones

Answer 23

• Severe starvation
• Uncontrolled diabetes

Question 24

List the clinical signs & symptoms that would result from excess ketones

Answer 24

Lungs giving the breath a characteristic sweet smell of acetone and the urine, since ketone bodies are acidic, an excess production can lower blood pH and cause metabolic acidosis

Question 25

One of the end products of amino acid catabolism is urea, state two tests could be done to check the levels of this product

Answer 25

• Nurses check for urea during urinalysis
• Blood tests - electrolytes and urea (U&E’s), blood urea nitrogen (BUN)

Question 26

State what elevated levels of this product would indicate

Answer 26

Kidney failure

Question 27

Define basal metabolic rate (BMR)

Answer 27

Is the metabolic rate measured under resting/fasting conditions

Question 28

State four factors that would increase BMR

Answer 28

• Exercise increases metabolic rate as much as 15 times
• Hormones increase basal metabolic rate
• Higher body temperature raises BMR
  Ingestion of food raises BMR 10-20%