Metabolic challenges & homeostasis

Question 1

• regulation of stable internal environment
• constant challenge of internal & external change
• internal functions maintained within tolerable limits
• adjustments made by negative & positive feedback systems

Answer 1

homeostasis

Question 2

how elephants survive in heat

Answer 2

• have excess skin = more space for heat to radiate off of body
• roll in mud = collects in wrinkles, holds moisture, evaporates like sweat
• blood circulates into ear = blood vessels open up to let air cool blood down, waft wars to create breeze

Question 3

how penguins survive in cold

Answer 3

• huddle together to share warmth
• feathers = thickly layered & waterproof, lift to trap insulating layer of air
• small, fat-lined feet = rock onto heals to reduce physical contact w/ ice

Question 4

how homeostasis works

Answer 4

• change detected in body sensors, nervous & endocrine systems
• counteract changes using effectors

Question 5

disturbed metabolism usually caused by imbalance between supply and demand for nutrients
- occasionally inherited due to endocrine function
- usually due to human interference = increasing demand for or reducing supply of nutrients

Answer 5

homeostasis failures

Question 6

calcium in the body

Answer 6

• 99% of calcium found in bones
• other 1% used in bodily functions
• important to maintain constant level

Question 7

• gut function, absorption & blood transport
• kidney filtration & reabsorption
• bone formation & reabsorption
• tissue growth or production

Answer 7

functions relying on calcium supply

Question 8

magnesium in the body

Answer 8

• 70% found in bones
• dissolved mg needed for enzyme activity for carb & lipid metabolism
• high in veg protein feeds
• low in rapidly growing grass

Question 9

diseases linked to homeostasis

Answer 9

• milk fever
• grass staggers
• fatty liver
• urolithiasis

Question 10

• low blood calcium
• 5-8% incidence in dairy herds
• dry cow needs 15g/day, early lactating cow needs 50-60g/day
• nervous system symptoms
• calcium or infusion
• prevention by increasing intake of calcium & vitamin D at calving

Answer 10

milk fever disease

Question 11

• rapid onset and/or sudden death
• low blood Mg
• higher risk in spring/autumn
• prevented by providing a constant flow
• cows require 20-30mg/day
  ewes require 2-3mg/day

Answer 11

grass staggers disease

Question 12

• induced by increased energy requirements but reduced energy intake
• especially susceptible = dairy cows at calving, alpacas & llamas in late pregnancy
• excessive mobilisation of body fat
• fat animals more at risk
• high levels of lipids in blood

Answer 12

fatty liver disease

Question 13

• salts precipitate in urine
• form crystals in bladder or kidney
• usually Mg & NH4 phosphate
• dogs, cattle & sheep more susceptible
• causes damage/blockage - bladder rupture

Answer 13

urolithiasis

Question 14

preceding factors of urolithiasis

Answer 14

• sex (males more at risk)
• diet
• infection
• alkaline urine
• some dog breeds more susceptible

Question 15

clinical signs of urolithiasis

Answer 15

• wide leg posture
• attempts to strain to pass urine
• small volumes of blood stained urine
• signs of crystals around penis

Question 16

preventing urolithiasis

Answer 16

• suitable & balanced diet
• avoid breeding from recurrent cases