Overview of metabolism Flashcards
tissues may be specialized for
storage function, anabolism (liver), or waster removal (kidney)
What products are transported through the body by the _____ system?
hormones, nutrients, waste products, ciruclatory
products of digestion go to two place
- Liver (water-soluble)
2. Blood (through the lymphatic system - fat-soluble)
Catabolism
breakdown, produces CO2 (must be removed)
Breakdown of proteins
produces nitrogen, must be disposed of
Anabolism
the buildup of complex substances in the cell from simpler ones as a part of metabolism
Waste elimination
- Respiratory System - disposes of CO2
- Urinary System - eliminates nitrogenous wastes
- GI Tract - unabsorbed food are excreted
Urea production 1/3
Nitrogenous waster arise from catabolism of aa’s
- Can be due to thee conversion for storage Orr from muscle for gluconeogenesis
- Bacteria in the lumen of the gut produce NH4+, must be removed due to it being toxic
Urea production 2/3
Can be due to thee conversion for storage Orr from muscle for gluconeogenesis
Urea production 3/3
Bacteria in the lumen of the gut produce NH4+, must be removed due to it being toxic
Kidney function
excreted water, minerals, and metabolic wasters (urea) through the bladder
glomerulus
tubules that will reabsorb water and solutes into the blood
The kidney controls ____ in order to what?
excretion in order to maintain homeostasis (RAAS)
fasting values of glucose
3.3-5.8 mm/L
_____ ____ in the blood must maintain constant in order for what to occur?
glucose levels to keep body processes functioning by supplying energy
metabolization of different substances
differ depending on how long it has been since a meal
Fed state
insulin dominates, after a meal, from the beginning to the end of absorption
Glucose in the fed state
Blood glucose levels rise, increasing insulin levels, decreasing glucagon
the liver will do what will the glucose in the fed state?
will use for immediate energy and replenish glycogen stores, stores some triglycerides
What occurs to the remaining glucose?
delivered to all the tissues, universal fuel source
Lipoproteins in the fed state
VLDL’s formed by the liver with triglycerides, protein, and cholesterol, for transport through the blood
chylomicrons
source of lipoproteins from the diet, formed in the intestines
Where do the triglycerides in VLDLs come from?
Source is from excess carbs and proteins that have been converted for storage
aa’s are used where to make what?
in the liver to make blood and liver proteins, can be used as precursors form DNA, RNA, heme, hormones and neurotransmitters (N-containing compounds)
tissues can use aa’s fo what
biosynthetic pathways
adipose tissue
used for long-term storage
fasted state
decrease in glucose levels, decrease in insulin, increase in glucagon
when does thee fasting state begin?
2 hrs after a meal due to blood glucose levels returning to fasting levels
how does the liver respond to the hormonal signals to control BGL?
glucagon signals the need for glycogenolysis so blood levels doo not fall too low
Glycogenolysis
breakdown of glycogen to glucose
glucogenesis
non-carbohydrate sources to produce glucose
what are the only thing that can use glucose as fuel?
RBC and brain
Why can RBC and brain only use glucose for fuel?
because they lack mitochondria
preferred fuel substrate for the brain and neural tissue
glucose
fuel control center during fasting
liver
liver can produce glucose from
glycogenolysis or glucogenosgeneesis
what dictates the glucose proportions?
fasting time
what supply is exhausted first in energy retrieval
glycogen soured in the liver, limited source
what can b used as precursors for glucose?
glycerol, lactate and amino acids
timeline of the metabolic process of the liver
glycogen synthesis, glycogenolysis, lipolysis, gluconeogenesis
Lipolysis
occurs at the same Tim as glycogenolysis, adipose triglycerides are broken down, yeieelding glycerol (for gluconeognesis) and freee fatty aids
muscles and other tissues will use what during fasting
fatty acids or Kenton bodies (mainly produced by the liver)
brain will us what during fasting
glucose (as will RNC, produced by gluconeogenesis)
prolonged fasting (starvation)
body must change its fuel metabolism as fasting continues, not allowing muscle wasting, muscle will increase its use of fatty acids as fuel, decrease use of ketone bodies
brain will do what during starvation
use greater % of ketone bodies for its needs so gluconeognesis slows, sparing muscle
40% of body weight
lost during starvation, death may occur
BMI in starved individuals
11 for women
13 for men
% of protein loss in starvation
30-50
% of fat loss in starvation
70-95
what can be used to secure the metabolic state of the individual?
blood and urine levels
change in fuel usage in prolonged fast in the brain
increased use of ketone bodies, decreased use of glucose
change in fuel usage in prolonged fast in the liver
decreased gluconeogenesis, decreased production of urea
change in fuel usage in prolonged fast in the muscle
decreased use of ketone bodies, decrease protein degradation
fuels are what?
carbs, fats and proteins which get stored
Where are ketone bodies made?
in the liver
Are ketone bodies used in the liver?
no
What effect do ketone bodies have?
acidic and drop pH
in protein fasting what source is used?
gluconeogenesis
Urea excretion: if someone is in the fed state are they creating more or less urea and why?
creating less urea b/c they are not using proteins
What is the time when we have used up alot of glycogen and gluconeogenesis is picking up?
12 hrs
3 days starving?
enough ketone bodies to use less amino acids and more ketones for brain
5-6 week starving
not enough of anything
