Digestion and stuff (SDA)

Question 1

How does the hypothalamus function neurally to influence homeostasis?

Describe hot and cold prevention

Answer 1

1. Heat -
   
   • ​Sweating - sympathetic on the sweat glands of the skin to produce sweat
   • Panting - sympathetic nervous, respiratory center
2. Cold -
   
   • Brown fat - increased epi in the blood will cause brown fat burning.
   • Shivering - increased sympathetic activity will cause conditions similar to light to moderate excercise:
     
     • fat burn, ATP production and CP production

Question 2

What are the 3 components of Caloric Expenditures?

Answer 2

1. Basal metabolic rate - 60%
   
   • fully rested
   • fasting
   • immobile
2. Thermogenesis - 10%
3. Physical Activity - variable

Question 3

Fever vs Hyperthermia

Answer 3

• Fever is a change in hypothalmic set point
• Hyperthermia maintains the same set point and therefore fails to maintain body temp.

Question 4

Describe the Fever pathway

Answer 4

1. Macrophages increase neural firing and plasma protein
2. Hypothalamus increases temperature set point
   
   • Skeletal muscle stimulation
   • Skin arteriole vasoconstriction

this all leads to more heat production and less heat loss

Question 5

What are the 3 ways skeletal muscle makes ATP for muscle contraciton?

Answer 5

1. Oxidative phosphorylation
   
   • aneoribic glucose metabolism
2. ADP phosphorylation
   
   • add phosphate to ADP
3. Creatine dephosphorylation
   
   • CP can give its phosphate to ADP in order to form ATP

Question 6

Describe what’s being burned/created at the following:

1. Rest/EPOC
2. Excercise [02 deficit]
3. Excercise [Steady-State]

Answer 6

1. Use fat. Make phosphocreatine, glycogen and “myoglobin” (fill)
2. Use fat, glycogen (glycolysis) creatine phosphate and myoglobin
3. Use fat and glycogen (oxi. phos.)

Question 7

What is meant by the term lactate threshold?

How can we influence this?

Answer 7

• the point at which lactate appears in the blood
• train more

Question 8

Compare and contrast Anterior Pituitary and Posterior Pituitary glands

Give some examples of Hormones released from

Answer 8

• Anterior: receives hormones via the hypophaseal portal system and then sends secondary hormones to various areas of the body to perform functions (most are tropic)
  
  • F.L.A.T. are tropic.
  • P.E.G. are direct
• Posterior: acts a neural reserovoir of hormones waiting for a neural response to release them
  
  • ADH and Oxytocin sit in the neural clefts waiting for stimulus

Question 9

How to make peptide hormones vs. steroid hormones

Answer 9

• Peptide: series of reactions and vesicles with other hormones. ends in exocytosis
• Steroid: Hormone signal → Adenyl cyclase → PKA → phosphoprotein → cholesterol is made into a product via enzymes.
  
  • Possible final products include: Cortisol, Aldosterone, Testosterone or Estradiol

Question 10

When are we in absorptive state or post-absorptive state?

Answer 10

• Absorptive state - is when we have just eaten recently. We are trying to burn through all of our glucose so we can finally burn our fat stores
• Post-absorptive state - we are burning fat stores. low effort imposed on the body. 12 hours after a meal

Question 11

What are limitations to muslce work being done?

Answer 11

• Demand/ need for carrier proteins to carry lipoproteins will slow the rate of their metabolism in muscle
• The rate of O₂ delivery reaches a point where it can no longer keep up with O₂

Question 12

How does increased stress lead to weight gain?

Answer 12

1. Cortisol is released via its pathway, causing your blood Glucose to “shoot through the roof”
2. Insulin is then released by the pancreas to compensate for this mass influx of glucose
3. Now your tissues have just absorbed all the blood glucose, which puts you back into the reabsorptive state

this leads to weight gain because you cannot burn fat in the absorptive state

Question 13

What if you intake more Na⁺. High BP or nah?

Answer 13

• if you intake more Na⁺ you should pee out more Na⁺ (remember pee lab)

Question 14

Why does Cholesterol Free olive sound contradictory or misleading?

Answer 14

there’s no cholesterol in plants

Question 15

Problem with excess sugar intake:

Answer 15

• More carbohydrates(wheat and sugar) we eat, the higher our blood glucose spike
• The higher our blood glucose is, the longer we are in the absorptive state. So we gain weight.

Question 16

How do you use Glycemic Index to differentiate foods?

Answer 16

It’s a scale of how fast you can absorb a type of food

• Higher GI = faster absorption (leaves you feeling hungry soon)
  
  • Fruits and processed grains
• Low GI = slower absorption (keeps you full longer)
  
  • unprocessed grains, proteins

Question 17

Compare and Contrast:

• Exogenous Fat pathway
• Endogenous Fat pathway

Answer 17

• Exogenous - all fat, no sugar
• Endogenous - all sugar, no fat

Question 18

think heart attack

Explain how plaques form in/around blood vessels

Answer 18

• as LDLs build up, the small (BB) LDL’s can squeeze through the Vessel lumen and get into the tissues
• this can become oxidized into radicals
• These radical LDLs accumulate into foam cells
• Foam cells accumulate in the tissues, when enough pressure forms, blood vessel ruptures

Question 19

What does PCSK9 do?

How do we rid excess cholesterol?

Answer 19

1. With PCSK9 involved, your LDL receptor is destroyed. This decreases LDL receptors.
   
   • Normally, LDL receptors are recycled, but now we don’t even have receptors to rid LDL, so it floats in circulation.
2. We rid this excess cholesterol with HDL!
   
   • HDL is produced by the liver, it scavenges cholesterol and converts it to bile salts

*it has been shown that Insulin plays a key role in the production of PCSK9…

Question 20

Why are High carb, frequent eaters at risk for DM and Heart complications?

Answer 20

Chronic High insulin:

• eventually their cells will lose receptivity
• PCSK9 production is stimulated, leading to less LDL receptors