AAP Endocrine System 2

Question 1

Where is the thyroid gland located?

Answer 1

• found on the ventral aspect of the first trachea

Question 2

What do thyroid glands secrete?

Answer 2

• T3, T4 and calcitonin
• T3: tri-iodothyronine (contains 3 atoms of trace element iodine)
• T4: Thyroxin(e) contains 4 atoms of trace element iodine

Question 3

What is the function of T3 and T4?

Answer 3

• regulates the metabolic rate of all the body’s cells (rate that body burns the nutrients to produce energy)
• allow the animal to generate heat and maintain a constant internal body temperature
• important for maintaining blood glucose level
• necessary for normal growth and development in young animals (CNS, muscles, bones)

Question 4

What is the function of calcitonin?

Answer 4

• modulate the calcium levels in the blood (decreases calcium level
• prevents hypercalcemia (excessively high blood calcium level) by encouraging excess calcium to be stored in the bones

Question 5

What is hypothyroidism and what are some symptoms associated with it?

Answer 5

• a condition of under-secretion of thyroid hormones
  Symptoms:
• stunted (dwarfism) growth in young animals
• in older animals, result in hair loss & slow heart rate
• may become fat and sluggish
• all due to reduced metabolic rate

Question 6

What is hyperthyroidism and hat are some symptoms associated with it?

Answer 6

• over-secretion of thyroid hormones
• hyperactive, aggressive activities
• increased appetite
• fast heart rate
• all die to an increased metabolic rate

Question 7

What is the parathyroid gland and where is it located?

Answer 7

• small, pale nodules in, on, or near the thyroid glands

- produces parathyroid hormone (PTH or parathormone)

Question 8

What is the function of parathyroid gland (PTH)?

Answer 8

• PTH helps to maintain blood calcium levels (increases calcium levels)
• prevents hypocalcemia by promoting: kineys to retain calcium, intestine to absorb calcium from food and calcium to withdraw from bones

Question 9

What is the pancreas and where is it located?

Answer 9

• an elongated organ
• mixed gland with both exocrine and endocrine functions
• endocrine component is organized into thousands of clumps of cells called pancreatic islets
• located in the curve of the duodenum

Question 10

What hormones are produced in the pancreatic islets?

Answer 10

• beta cells (produces insulin)
• alpha cells (produces glucagon)
• delta cells (produce somatostatin

Question 11

What is the purpose of insulin?

Answer 11

• produced in response to high blood glucose levels
• insulin decreases blood glucose by increasing the uptake of glucose into the body cells and used as energy
• storing excess glucose as glycogen in the liver (through a process called glycogenesis)
• lack of insulin leads to diabetes mellitus
• animal with this condition suffer from excessively high blood glucose; if left untreated, the condition progresses to a stage where the body breaks down protein and fat sources (sources of energy) which results in significant organ damage

Question 12

What is the purpose of glucagon?

Answer 12

• produced in response to low blood glucose

- glucagon breaks down the glycogen stores in the liver to generate glucose via glycogenolysis

Question 13

What is the purpose of somatostatin?

Answer 13

• inhibits the secretion of insulin and glucagon

- act on the GI tract to decrease the activity of the GI tract

Question 14

Where is the adrenal gland located and what does it consist of?

Answer 14

• pair of adrenal gland located at the cranial ends of the kidneys
• consist of adrenal cortex and adrenal medulla

Question 15

Which part of the adrenal gland is the cortex and medulla?

Answer 15

• adrenal cortex refers to the outer portion of the adrenal gland
• adrenal medulla refers to the inner portion of the adrenal gland

Question 16

What is the function of the adrenal cortex?

Answer 16

• produces hormones that are classified into 3 groups:
• mineralocorticoids
• glucocorticoids
• sex hormones

Question 17

What is one of the most important mineralocorticoids and what is its function?

Answer 17

• aldosterone
• acts on the kidney (at the DCT) to regulate the acid/base balance
• by increasing the reabsorption of sodium ions in exchange for K+ and H+

Question 18

What is one of the most important glucocorticoids?

Answer 18

• AKA corticosteroids
• cortisone and corticosterone
• maintain blood pressure
• stress relief
• anti-inflammation
• immunosuppression
• increases metabolic rate

Question 19

What are the functions of sex hormones?

Answer 19

• male animals produce androgens
• females produce estrogens
• small quantities with minimum effect
• important for maintaining secondary sexual characteristics

Question 20

What is the function of the adrenal medulla?

Answer 20

• produces epinephrine (AKA adrenaline)
• norepinephrine (noradrenaline)
• these hormones prepare the body for emergency action (flight or fight)
• secretion of these hormones are under involuntary control (automatic nervous system)

Question 21

What are the functions of epinephrine and norepinephrine?

Answer 21

• raise blood glucose levels by breakdown of glycogen in the liver (energy)
• increase the heart rate and respiration (meet high dd for oxygen)
• dilate the blood vessels of the skeletal muscles (increased supply of glucose and oxygen)
• decrease the activity of the GI tract and the bladder (functions less important in emergency)

Question 22

What are the main hormones produced in the ovaries?

Answer 22

• oestrogen
• progesterone
• relaxin

Question 23

What is the function of oestrogen?

Answer 23

• produced by ovarian folliles
• causes the behaviour associated with the estrus cycle in female animals
• prepares the reproductive organ for mating

Question 24

What is the function of progesterone?

Answer 24

• secreted by corpus luteum
• prepares the reproductive organs for pregnancy
• causes the development of the mammary glands during pregnancy

Question 25

What is the function of relaxin?

Answer 25

- in the later stages of pregnancy | - softens and relaxes ligaments around the birthd canal to prepare them for fetus delivery

Question 26

What hormone do the testes produce?

Answer 26

- testosterone

Question 27

What is the function of testosterone?

Answer 27

- released in response to the secretion of interstitial cell-stimulating hormone (ICSH) - leads to the development of male characteristics: muscle development, male behavioural patterns (e.g. territorial behaviour), development of sperm

Question 28

What hormone is secreted by the kidney?

Answer 28

- erythropoietin - secreted in response to a decrease in blood oxygen (hypoxia) - increases the production of RBCs by acting on the bone marrow

Question 29

What hormone is secreted in the small intestine?

Answer 29

- secretin - food stimulates the wall of the small intestine to produce this hormone - secretin stimulates the secretion of intestinal and pancreatic juices to facilitate the process of digestion

Question 30

What hormone does the pineal body/glannd produce?

Answer 30

- the pineal gland is a very small organ with pine cone-like shape - located deep in the centre of the brain - produces the hormone melatonin: maintains circadian rhythm (affect mood and wake-sleep cycle) - regulates reproductive hormones (affects estrus cycle in some animals