Metabolism and Organ Function Practice Flashcards

The Body's Resource Consumption Sequence:
- When the body is fasting or starving, it follows a specific hierarchy of energy source utilization.
- Carbohydrates and Glycogen: The body first uses all available carbohydrate stores, including any sugar stores and glycogen.
- Proteins: Once sugar stores are exhausted, the body enters a phase of "eating itself." It begins to break down proteins for energy, starting with the muscles.
- Fats: Fat stores are metabolized after the body has begun utilizing protein reserves.

Definition of Gluconeogenesis: This is the process of generating glucose from non-carbohydrate sources, specifically protein breakdown.
Organ Site: Gluconeogenesis occurs primarily in the liver.
Bodybuilding and Muscle Preservation:
- If an individual does not eat carbohydrates, they can lose muscle mass because the body will utilize proteins for fuel via gluconeogenesis.
- Bodybuilders are advised to eat a combination of carbohydrates and significantly more proteins.
- Mechanism: Carbs are consumed to be used as primary fuel, allowing the dietary protein to go toward building muscle walls and tissue rather than being "cut" or used for energy production.
- Fundamental Principle: "You can't grow without eating."
Fasting Caution: It is emphasized that one should not eat too quickly or excessively after a fast, as metabolic processes need to stabilize. Additionally, when trying to metabolize or exercise, consuming too much fat is discouraged.

Tissue Perfusion: Defined simply as "flow" or circulation. Poor tissue perfusion means inadequate blood circulation.
Shock and Anaerobic Glycolysis:
- Patients in shock experience poor tissue perfusion, leading to a rise in lactic acid.
- The rise in lactic acid is explained by cells utilizing anaerobic glycolysis.
- Mechanism: When cells lack oxygen (anaerobic conditions), they break down sugar without oxygen, which produces lactic acid as a byproduct.

Triglyceride Composition: Triglycerides consist of one glycerol molecule (which is a glucose) and three fatty acids.
Sugar and Fat Relationship: Excessive sugar consumption leads to high triglycerides because sugar turns into fat. Without the sugar molecule, there is no binding with the fatty acids to form the triglyceride.
Storage: Triglycerides are stored as fuel and eventually become adipose tissue.
Functional Roles of Lipids:
- Insulation: Adipose tissue keeps the body warm during cold temperatures.
- Cell Walls: Lipids help secure cell walls; specifically, cell membranes are made out of phospholipids.
- Transport: Lipids travel through the blood as LDOs (low-density lipoproteins) and HDOs (high-density lipoproteins).
- Steroid Production: Lipids are essential for making steroids, including cholesterol, Vitamin D, and sex hormones such as testosterone.
Metabolic Breakdown: Lipids break down into fatty acids, which then break down into Ketones.

The Liver as a Protein Factory: The liver is responsible for producing a wide array of essential proteins.
Synthesized Proteins:
- Hemoglobin
- Antibody (Antibodies)
- Enzymes
- Albumin
Clinical Correlation (Liver Cirrhosis):
- Damage to the liver (e.g., via alcohol consumption) disrupts these functions.
- Failure to produce proteins like albumin leads to issues with water regulation in the tissues (edema).
- Knowledge of organ function is prerequisite to understanding signs and symptoms of diseases.

Amino Acid Breakdown: When proteins/amino acids are broken down in the liver, they produce nitrogenous waste.
Chemical Components: The body is made of "CHON" (Carbon, Hydrogen, Oxide, Nitrogen). Nitrogen is a byproduct of the 90% protein breakdown occurring in the liver.
The Waste Pathway:
1. Protein Consumption: Protein is eaten and moves to the small intestines.
2. Absorption: The small intestines absorb amino acids and send them to the liver.
3. Liver Processing: The liver breaks down amino acids, recycling some and turning others into nitrogenous waste.
4. Ammonia Production: The liver makes ammonia (a toxic gas).
5. Urea Conversion: The liver converts ammonia into urea.
6. Kidney Excretion: The urea is sent to the kidneys and excreted as urine.

Creatinine: Used to check kidney function.
- Normal range: $0.5$ to $1.2$
- Levels above $1.2$ indicate potential kidney failure.
BUN (Blood Urea Nitrogen):
- Normal range: $7$ to $22$
- Levels above $50$ are highly concerning for kidney failure. Elevated levels (e.g., $30$ ) may simply indicate dehydration.
Albumin: Used to check for liver failure.
- Normal range: $3.5$ to $5.0$
- A level of $1.0$ indicates the liver is not functioning correctly.
Ammonia: Used to check for liver dysfunction.
- Normal range: Generally under $75$ . Anything greater than $75$ is noted as elevated.

Hepato Encephalopathy: A condition where high ammonia levels ( > 75) affect brain circulation.
Symptoms: Irritability to the brain and changes in mental status (acting "crazy" or not like themselves).
Metabolic Assessment for Mental Change: When an elderly patient has a mental status change, always check:
1. Oxygen levels.
2. Glucose levels.
3. Ammonia levels.
4. Check for UTIs (Urinary Tract Infections).

Q: What are amino acids?
- A: Proteins (the building blocks of proteins).
Q: Where does gluconeogenesis happen in? What organ?
- A: The liver.
Q: If you don't eat carbs, can you lose your muscles?
- A: Yes, because of gluconeogenesis.
Q: Why is lactic acid building up in a shock patient?
- A: Because the cells have no oxygen; they are using anaerobic glycolysis.
Q: What do triglycerides consist of?
- A: One glycerol and three fatty acids.
Q: Which organ makes ammonia?
- A: The liver.
Q: Which organ turns ammonia into urea?
- A: The liver.
Q: Which organ gets rid of urea?
- A: The kidneys.
Q: Where does nitrogen come from?
- A: Protein breakdown.
Q: Any question on LDOs and HDOs?
- A: [No response recorded].