Animal Nutrition

Question 1

What are the 4 classes of essential nutrients?

Answer 1

1. Essential amino acids
2. Essential fatty acids
3. Vitamins
4. Minerals

Question 1

What is the purpose of consuming organic molecules and essential nutrients?

Answer 1

Organic nitrogen and carbon are needed to construct organic molecules, and essential nutrients are required by cells to function

Question 2

What is an essential amino acids?

Answer 2

20 molecules that are required to make up proteins.

Question 3

What is the difference between a complete protein and an incomplete protein?

Answer 3

Complete: contains all amino acids (e.g. red meat, eggs, cheese)

Incomplete: lacks one or more essential amino acids (e.g. plant proteins)

Question 4

What are essential fatty acids and how do animals obtain them?

Answer 4

Essential fatty acids are certain unsaturated fatty acids that must be obtained by the diet.

Question 5

What are vitamins and what do they do? How many are essential?

Answer 5

Vitamins are organic molecules required in the diet in small amounts. There are 13 essential vitamins and are grouped as either fat soluble or water soluble

Question 6

What are minerals and what do they do?

Answer 6

Minerals are inorganic nutrients required in small amounts that act as an enzyme’s cofactors.

Question 7

What is undernourishment and what are 4 symptoms of it?

Answer 7

Undernourishment is the result of a diet that consistently supplies less chemical energy than the body requires. It results in:

1. the use of stored fats and carbohydrates and proteins as energy
2. loss of muscle mass
3. protein deficiency in the brain
4. in extreme cases, irreversible damage/death.

Question 8

What is malnourishment and what can it cause?

Answer 8

Malnourishment is the long-term absence of the diet of one or more essential nutrients that may cause deformities, disease, and death.

Question 9

What is an example of how evolutionary adaptations of vertebrate digestive systems correlate with diet?

Answer 9

Dentition (assortment of teeth) as well as stomach/intestinal adaptations in carnivores, herbivores, and omnivores are adapted to their diet.

Question 10

How does vertebrate dentition correlate with diet?

Answer 10

carnivores: primarily canines and incisors for meat
herbivores: primarily premolars and molars for chewing
omnivores: equal assortment of canines, incisors, premolars and molars.

Question 11

How does vertebrate stomach and intestinal adaptations correlate with diet?

Answer 11

Carnivorous vertebrates have a large expandable stomach to store food in since they may go for a long time between meals

Herbivores have a longer cecum and a larger colon as vegetation requires a longer time to digest due to plant cell walls.

Question 12

What is the gut microbiome and what does it do?

Answer 12

The gut microbiome is the sum of 10-100 trillion bacteria in the human digestive system. They augment chemical breakdown, produce vitamins, and regulate the development of epithelium and function of immune system.

Question 13

What is coprophagy?

Answer 13

Coprophagy is when rabbits and some rodents feed on their own feces. They do his because when they first ingest their food, mutualistic bacteria in the large intestine and cecum break down cellulose to simple sugars which gets passed down to their droppings. They feed on their feces to pass it through the alimentary canal a second time and absorb what the bacteria broke down.

Question 14

What are the stages of urine formation?

Answer 14

1. glomerular filtration
2. PCT reabsorption
3. PCT secretion
4. Water reabsorption
5. DCT regulated reabsorption/secretion
6. Collecting + Final adjustments

Question 15

How does glomerular filtration in the nephron work?

Answer 15

• change in the size of arterioles results in high pressure flow of blood through glomerulus
• filtrate is absorbed by bowman’s capsule while podocytes restrict the flow of blood cells and plasma
• blood left in efferent arteriole is concentrated with blood cells and plasma proteins and low in essential nutrients and fluids
• filtrate in bowmans capsule is high in both nutrients and fluids

Question 16

how does PCT reabsorption in the nephron work?

Answer 16

• sodium ions are actively transported into intercellular spaces creating a charge imbalance and letting chloride ions follow via passive transport
• low osmolarity in PCT and high osmolarity in blood creates osmotic gradient that draws water into the blood from PCT
• this increases filtrate concentration and small amounts of urea and uric acid will diffuse back into the blood

Question 17

How does PCT secretion in the nephron work?

Answer 17

• water from PCT contains waste products that needs to be excreted so it is secreted back into the nephron
• these wastes include ammonium ions, excess hydrogen and potassium ions (maintains blood pH), urea, uric acid, creatinine, some drugs like antibiotics

Question 18

How does water absorption in the nephron work?

Answer 18

• descending limb of loop of henle is permeable to water + impermeable to salts, while ascending limb is impermeable to water and actively transports out salt
• salt that is transported into interstitial fluid of the inner and outer medulla causes osmotic gradient which draws out water from the water permeable descending limb
• concentrated filtrate moves up ascending loop trapping leftover water in water impermeable ascending limb and sodium is reabsorbed into blood

Question 19

How does DCT absorption in the nephron work?

Answer 19

• DCT reabsorbs and secretes based on the needs of the body
• DCT reabsorbs H+ or secretes HCO3- (bicarbonate) to regulate body pH and bring it down to low body pH
• dehydration makes Na+ and K+ levels increase to draw out more water
• DCT is the main area of calcium reabsorption and urea secretion

Question 20

How does water collection work in the nephron?

Answer 20

• DCT’s merge into collecting ducts which are impermeable to water (which creates dilute urine)
• Reabsorption and secretion in the collecting duct is heavily influenced by hormonal activity

Question 21

What is the juxtamedullary nephron?

Answer 21

Nephron with loops of Henle extending deep into the medulla that has a urine concentrating effect conributing to water conservation in terrestrial animals.

Question 22

How do birds, reptiles, and amphibians conserve water?

Answer 22

Birds: short loops of Henle, but conserve water by excreting uric acid as a paste instead of urea.

Reptiles: water is reabsorbed by epithelium of chamber from which urine and faeces leaves the body AND excrete nitrogenous waste as uric acid

Amphibians: reabsorb water from the urinary bladder