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Lipids – Part 2. McCafferty. LIPID DIGESTION & ABSORPTION. Absorbable forms:. Remember “hydrolysis?”. Mouth Mechanical: chewing, mixed w/saliva for lubrication Chemical: . Stomach Mechanical: peristalsis/churning  ____________ Chemical: .

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Lipids part 2

Lipids – Part 2

McCafferty


Lipid digestion absorption
LIPID DIGESTION & ABSORPTION

  • Absorbable forms:



Lipids part 2

  • Mouth

  • Mechanical: chewing, mixed w/saliva for lubrication

  • Chemical:


Lipids part 2

  • Stomach

  • Mechanical: peristalsis/churning ____________

  • Chemical:


Lipids part 2


Lipids part 2


Lipid absorption
Lipid Absorption emulsified

  • Small lipid fragments:

    • Glycerol and Short Chain FAs (SCFAs)

    • Absorbed directly into the bloodstream

    • Portal vein to liver


Lipid absorption1
Lipid Absorption emulsified

  • Big lipid fragments

    • Monoglycerides and LCFAs need help!

    • If absorbed into the blood:

    • They need to be emulsified.


Big lipid fragments cont
Big lipid fragments, cont. emulsified

  • Enter intestinal cell, re-form TG

  • TG is incorporated into Lipoprotein carriers: Chylomicrons (CM)

    • Lipoprotein = lipid associated w/proteins

      • “Shuttle”

    • Protein and phospholipid act as emulsifiers for the other lipids


Lipids part 2

  • Lymph vessel emulsified  

  • The tissues can extract what they need from the CMs.

  • CM remnants 


Lipoproteins overview
Lipoproteins -- Overview emulsified

  • Lipids bound to protein

  • Spherical structure –

    • “Shuttle”


Classes of lipoproteins
Classes of Lipoproteins emulsified

  • What is denser, lipid or protein?

  • CM chylomicron –

    • made in intestinal cells

    • Transports ________TG from ________ to tissues

      • eg. adipose and muscle

  • VLDL – very low density lipoprotein

    • made in liver

    • Carries TG to tissues


Lipids part 2

  • LDL emulsified –

    • Made in liver

    • Carries

  • HDL –

    • Made in liver & intestine

    • Associated w/ risk for CVD


Recommended levels
Recommended Levels emulsified

  • Total cholesterol

    • For  30 yrs

    • For  30 yrs

    • (for kids  170 mg/dl)

  • LDL cholesterol

  • HDL cholesterol

  • Triglycerides (TG)

  • *note controversy surrounding these numbers


Lipids part 2

  • LDL to HDL ratio emulsified

    • Men:

    • Women:

  • LDL cholesterol increases with

  • HDL cholesterol increases with


Storage use of fat
STORAGE & USE OF FAT emulsified

  • Overview:

    • TG is main form of stored E in the body

    • Adipose –

    • When body needs fuel


Storing fat
Storing Fat emulsified

  • TG in blood (in CMs and VLDL)

    • (need to get TG into adipose & muscle cells)

  • INSULIN present

    • Activates enzyme on blood vessel wall:

    • LPL Lipoprotein Lipase

    • LPL binds w/CM or VLDL and extracts TG

    • Breaks down TG  glycerol & 3FAs  enter cell


Storing fat1
Storing Fat emulsified

  • In adipose, TG  fat droplets


Storing fat2
Storing Fat emulsified

  • In adipose, TG 

  • Adipose cells stretch to hold  fat

  • Once filled to max capacity, cells begin to multiply


Mobilizing stored fat
Mobilizing Stored Fat emulsified

  • TG in adipose; want to release FAs for E

    • Activates enzyme inside adipose cell

    • HSL Hormone-sensitive lipase

    • HSL breaks down TG  G & FAs

    • FAs  blood

      • Hydrophobic, so bound to protein carrier: albumin

      •  cells  metabolized for E


Using fat to make atp

USING FAT TO MAKE ATP emulsified

What kind of fat gets used for energy?

What is triglyceride made of?


Lipids part 2

______________ emulsified

C-C C-C C-C

C-C C-C C-C

C-C C-C C-C

C-C C-C C-C

C-C C-C C-C

C-C C-C C-C

C-C C-C C-C

C-C C-C C-C

C-C-C

_____________

_____________

C-C

Krebs

ATP

ETS


Lipids part 2

  • Glycerol emulsified is converted to pyruvate

    • can either glucose or acetyl CoA/Krebs/ATP

  • Fatty Acids (too large to enter Krebs cycle)

    • can ONLY enter energy metabolism at


Lipids part 2


So what s the point
So what’s the point? emulsified

  • If we are out of glycogen and need to make glucose for those glucose-dependent tissues, we aren’t going to be able to use fatty acids to do it.


Summary of atp production from fat
Summary of ATP Production From Fat emulsified

  • Fat is comprised mainly of TG molecules

    • Glycerol and 3 FAs

  • Glycerol (3C) enters energy metabolism at pyruvate

  • FAs (broken down to 2C units) enter at acetyl CoA

  • Fat can provide a very small amount of glucose form the glycerol

  • Complete oxidation of TG yields ATP, CO2, H2O and body heat.



Cardiovascular disease general term for diseases of the heart and blood vessels
Cardiovascular Disease emulsified– general term for diseases of the heart and blood vessels

  • Coronary Heart Disease (CHD) – AKA Coronary Artery Disease– lack of blood flow to the network of blood vessels surrounding (and serving) the heart.

    • major cause: atherosclerosis.

  • Atherosclerosis – thickening and hardening of the walls of the blood vessels 2 deposits of fatty material (plaque)

    • esp. coronary and carotid arteries and abdominal aorta


Lipids part 2

  • Heart Attack emulsified – Lack of blood flow to the heart muscle resulting in tissue damage and sometimes sudden death

  • Stroke –blood flow to a part of the brain is cut off

    • “brain attack.”

    • Usually due to atherosclerosis in the carotid arteries.


Atherosclerosis
Atherosclerosis emulsified

  • Slow, progressive disease which begins in childhood and takes decades to advance.

    • Coronary arteries are most often affected.


Lipids part 2

  • “Response to Injury Theory” emulsified

    • Fatty streaks form along arterial walls

    • Proliferation of smooth muscle cells, WBCs and calcium  plaques

      • Plaques cause the arteries to lose elasticity


Lipids part 2


Lipids part 2

  • Angina: emulsified

    • pain, pressure, and tightness in chest, back, neck, and arms

    • caused by

  • Hypertension


Lipids part 2

The FOUR major risk factors: emulsified

  • Smoking

    •  HDL,  BP, increases platelet stickiness (clots)

  • Hypertension

    •  cardiac work,  arterial damage

    • Risk :


Lipids part 2

3. Elevated blood cholesterol emulsified

  • major lipid in plaque

    4. Lack of regular exercise

  • Sedentary people (60% of US) have double the risk of developing CVD as active people.


Lipids part 2

Other risk factors include: emulsified

  • Heredity – parent or sibling male under 55, woman under 65

  • Gender – male

    • women post menopause without estrogen

  • Age

  • Stress and personality type

    • Type “A” personality, stress, depression

  • Elevated triglycerides

    • Inversely correlated w/HDL’s


Lipids part 2

  • Homocysteine emulsified

    • Strong + correlation w/premature disease

    • with inadequate B vitamins

      • (folate, B6 and B12 – fruits and veggies, lean meats)

    • Also:


Exercise
Exercise emulsified

  • Strengthens heart muscle

  • Lower body fat (also affects diabetes)

  • Better glucose control

  •  blood pressure

  •  stress

  • Exercisers are less likely to be smokers

  • Improved lipid profile (LDL, HDL)

  •  blood clotting


Dietary prevention of heart disease
Dietary Prevention of Heart Disease emulsified

  • Fat

  • Saturated fat

  • Mono vs. Poly

  • Trans FAs

  • Sodium


Lipids part 2

  • Alcohol emulsified

  • Antioxidants and Phytochemicals

  • Fiber

  • Fish

  • Soy