Carb & Lipid Metabolism Flashcards
Obj: Describe classes of lipids, their structure and nomenclature
Obj: Explain mechanisms of lipid digestion and absorption
Obj: Describe lipid transport in the body and metabolism
Obj: Recognize essential fatty acids (EFA) and determine their functions)
Obj: Summarize clinical signs of EFA deficiency
Obj: Outline lipid assessment of an animal
What is the difference between Lipids, Fats, and Oils?
- lipids - organic substances that are relatively insoluble in water and soluble in organic solvents
- fats - solid at room temp
- Oils - liquid at room temp
How many carbons are short, medium, and long chain fatty acids?
- Short-chain: <8 carbons
- medium-chain: 8-12 carbons
- Long-chain: >12 carbons
What is the difference between a Cis and Trans Fatty Acid
- Cis Double bond
- Hydrogen atoms positioned on same side of double bond
- Trans Double bond
- Hydrogen atoms are on opposite sides of double bond
What is Alpha nomenclature of Fatty Acids
- Based on positions and types of double bonds relative to the carboxylic (α) end of the fatty acids
What is Omega nomenclature of Fatty Acids?
- Fatty acids categorized into groups based on where the first double bond is located relative to the methyl end
- “n” system
What are Mono-, Di-, and Triglycerides?
- Lipids made of a glycerol bonded to # Fatty acids
- mono - 1
- di - 2
- tri - 3
How are lipids digested?
- Emulsification by bile salts
- TAG → MAG + NEFA by lipase
- SCFA + MCFA (14) - portal blood
- MAG + LCFA (>C12) - absorbed as micelles
What do micelles do?
- Transport:
- Pancreatic lipase
- Cholesterol
- bile salts
- fat soluble vitamins
How are lipoproteins differentiated
- distinguished by size and density
- each contains different kinds and amounts of lipids and proteins
- more lipid = lower density
- more protein = higher density
What is Low-Density Lipoproteins?
- ‘Bad Cholesterol’
- Major lipid is cholesterol
- Delivers cholesterol from liver to body cells
- cell membranes
- hormone production
- Protein 21% - binds to specific LDL receptor
What are High-Density Lipoproteins
- ‘Good Cholesterol’
- Liver and intestine
- Major lipid is phospholipid
- Transports cholesterol to the liver from body cells
- picking up cholesterol from dying cells and lipoprotein metabolism
- Protein 50%
What lipoprotein is associated with a lower risk of cardiovascular disease?
High-density lipoprotein
What are the functions of EFAs?
- Omega-6:
- Pro-inflammatory
- Omega-3:
- Cyclooxygenase (COX)
- Lipoxygenase (LOX)
- Anti-inflammatory
Why is Docosahexaenoic acid (DHA) necessary for puppies?
- Omega-3 fatty acid
- Quicker response to light
- improved visual performance
- Improved sensitivity to dim light
- Improved trainability/learning
What are the clinical signs of an EFA deficiency?
- Dermatitis - irritated & flaky skin
- Poor haircoat
- Poor feathering
- GI problems
- Compromised Immune system
- Slow growth
- Reproductive failure
What is lipolysis?
- Breakdown of triglycerides, fatty acids, and glycerol
- Stimulated by:
- Starvation - hypoglycemia
- Exercise
- Physiological stress
What is Hormone-sensitive lipase?
- Enzyme that catalyzes the hydrolysis of ester bonds that attach fatty acids to the glycerol molecule
- Mobilizes fatty acids from adipose tissue
- Triglyceride synthesis, β-oxidation, ketogenesis
What is ketogenesis?
- Conversion of FFA to ketone bodies
- acetoacetate, β-hydroxybutyrate, acetone
- Occurs when body’s supply of glucose becomes limited - ‘low carb’
- measurable in blood and urine
