FORM & FUNCTION (Starvation 2)

Question 1

Late (severe) phase of starvation:

Answer 1

-begins once fatty acid, ketones deplete
*utilize proteins

Question 2

Protein utilization:

Answer 2

-from tissues are broken down to provide AA
-AA to alpha-keto acids
>gluconeogenesis
>ketogenesis
>NOT lipogenesis

Question 3

Body protein depletion order:

Answer 3

1. Digestive enzymes (stomach, pancreas, small intestine)
2. Liver enzymes that process incoming nutrients form the intestine (ex. bile acid formation)
3. Muscle

Question 4

Muscle:

Answer 4

-body’s largest supply of protein
-animal becomes inactive (breakdown of contractile fibers)

Question 5

Ubiquitin-proteasome system:

Answer 5

1. Protein substance is tagged with ubiquitin (requires ATP)
2. Proteasome recognizes the protein+ubiquitin and starts breaking down the quaternary protein
3. Polypeptides are further broken down by proteases into AA

Question 6

AA catabolism overview:

Answer 6

-60% of AA released will be alanine and glutamine
-AA to alpha-keto acid + glutamate
>alpha-keto A to Alanine (then to pyruvate)
>glutamate to Alanine or glutamine

Question 7

Alanine and glutamine:

Answer 7

-alanine goes to liver: gluconeogenesis and get urea (nitrogenous waste)
-glutamine goes to kidney: gluconeogenesis and get ammonium (nitrogenous waste)
*mechanism to generate glucose and to remove nitrogen waste

Question 8

AA deamination results in:

Answer 8

-high levels of glutamate
-muscle sacrifices pyruvate to recycle these into alanine (sent to liver)
-pyruvate + glutamate=alanine and alpha-ketoglutarate

Question 9

Additional glutamate:

Answer 9

-converted to glutamine and exported to kidney
>NH3+ added with ATP

Question 10

Alanine processing:

Answer 10

-transported to liver for gluconeogenesis
- high levels of alanine aminotransferase (ALT) in the liver
>alanine to pyruvate: by-product of NH3+ goes to urea cycle

Question 11

Urea cycle:

Answer 11

-primary site is in the liver
-a process to remove toxic nitrogen buildup

Question 12

Glutamate processing:

Answer 12

-glutamine is transported to the kidney to support gluconeogenesis
-glutaminase activity is high in the kidney (glutamine to glutamate)
-most NH4+ is excreted in urine/filtrate, even though kidney can perform the urea cycle

Question 13

Late starvation summary:

Answer 13

-fat store depletion
-increase gluconeogenesis
-increase muscle wasting/proteolysis
-compromised liver function

Question 14

Complications of late starvation:

Answer 14

-edema
-shock
-coma

Question 15

Role of liver:

Answer 15

-gets AA
1. gluconeogenesis (to brain, RBC)
2. Ketones (to extrahepatic tissues)
3. Protein synthesis (to plasma proteins)
*these processes compete for AA
*maintaining glucose and ketones production hinders protein synthesis

Question 16

Serum albumin (protein);

Answer 16

-plasma protein is 60% serum albumin
-transports protein and fatty acid
-maintain plasma colloid osmotic pressure

Question 17

Hydrostatic pressure;

Answer 17

-pushes out of vessel

Question 18

Osmotic pressure:

Answer 18

-pulls in

Question 19

Starvation compromised liver function:

Answer 19

-decrease serum albumin (decrease FFA transport)
-decrease osmotic pressure (hydrostatic pressure is greater and pushes liquid out of vessel)
-increase plasma fluid LOSS

Question 20

Physiological consequences of decreased serum albumin:

Answer 20

-plasma fluid enters interstitial space (edema)
OR
-abdominal cavity (ascites)
*leads to blood volume depletion (hypovolemia) and impairs O2 delivery to organs
*then results in shock or coma leading to death

Question 21

Risk of pneumonia:

Answer 21

-immune system compromised
-protein degradation can lead to loss of myofibrillar proteins in muscles that function in respiration

Question 22

Muscles that function in respiration:

Answer 22

-diaphragm and integral costal (inspiration)
-abdominal and external muscles (power force expiration, ex. coughing)

Question 23

Unable to cough:

Answer 23

-leads to increase risk of lunch and bronchioles infection
*high risk of infection leads to respiratory failure