ANS 230 Lecture 9 : Integration of Metabolism, Absorptive and Post Absorptive States

What is the entire GI tract innervated by?

Arteries and Veins

What does the GI tract require a lot of?

Circulation of Blood

What is the role of blood circulation in the GI tract?

Mobilize feed that gets absorbed

What is the main vein that transports pretty much the majority of nutrients from the GI tract to the liver and other organs?

Hepatic Portal Vein

What is a good way to know how digestible a nutrient is?

Collect the blood in the Hepatic Portal Vein and analzye

What are the Two Physiological States of Energy Metabolism?

The Absorptive and Post-Absorptive States

Is The Absorptive State anabolic or catabolic?

Anabolic

Is the Post-absorptive state anabolic or catabolic?

Catabolic

When does the Absorptive State occur?

During and after a meal

When the feed is in the GI Tract, it is in the ______ ______

Absorptive State

What supplies the nutrients to the blood and lymph?

The GI Tract

What regulates blood glucose?

The Liver

During the absorptive states, which two blood nutrients raise in level?

Blood glucose and Blood lipid

What is another word for an increase in blood glucose?

Hyperglycemia

What is another word for an increase in Blood lipid?

Lipemia

How does the body store excess “fuel”

As either glycogen or triglycerides

What is the absorptive state- Major Metabolic Pathways for carbohydrates?

• Glycolysis → TCA→ ETC for ATP production

• Glycogenesis for the production of glycogen (storage) in the liver and muscle

What is the absorptive state- Major Metabolic Pathways for Lipids?

• Fatty Acid and Triglyceride synthesis in the liver

• Storage in adipose tissue (lipogenesis)

What is the absorptive state- Major Metabolic Pathways for Proteins?

• Amino Acids used for protein synthesis

• Excess Amino Acids converted to glucose or fat

When does the Post-absorptive state occur?

It occurs between meals

Why is there minimal absoprtion from the GI tract during the Post-absorptive state?

This is because there is no feed in the stomach or intestine (parts of the GI tract)

Where do animals get their energy from between meals?

They get their energy from the fuels that are stored during the absorptive state

What are the three major fuel sources in the Post-absorptive State?

Liver, Adipose, and Peripheral tissues

What is the main source of energy in the liver during the postabsorptive state?

Glucose gained from glycogenesis and Glucsoe gained from gluconeogenesis

What is the main source of energy in the adipose tissue during the postabsorptive state?

Fatty acids

When animals fast enough to the point of stavation, how do they get their energy?

The breaking down of their fat storages - if it goes farther they break down muscle

In the post-absorptive state the body _______ _____ ______

mobilizes stored energy

Where do animals primarily get their energy from while in the post-absorptive state?

The Liver and adipose tissue

Where does gluconeogenesis occur in the post-absorptive state?

Lactate, Amino Acids, and Glycerol

How do Fatty Acids generate energy in the post-absorptive state?

Fatty acids are converted to Acetyl-CoA, which is then produced into ATP through TCA Cycle

What decision occurs at the Acetyl-CoA junction?

Animals make a decision whether or not they have the TCA Cycle to rely on for energy or if they need to get energy in a different route

When there is not enough oxygen, what happens to Pyruvate?

Instead of being converted to Acetyl Co-A, it is converted to Lactic Acid.

What happens to excess acetyl-Coa in the post-absorptive state

It is stunted towards the ketone body

What causes Acetyl-CoA to not go into the TCA cycle?

An insufficient amount of oxaloacetate

What occurs in the blood during the post-absorptive state?

Reduced levels of glucose and insulin. Increased levels of glucagon.

THIS ISNT ON THE LECTURE BUT

What is Glucagon?

Glucagon is peptide hormone produced in the pancreas that acts as a critical regulator of glucose metabolism. It increases blood sugar levels by stimulating the liver to convert stored glycogen into glucose.

Can Fatty Acids cross the blood-brain barrier?

No, energy has to be in the form of glucose (carb)

Under extended periods of starvation, what can meet the energy requirements of the brain?

Ketone bodies

Can Red Blood Cells get energy from ketone bodies?

No

Do the red blood cells have mitochondria?

No

How do red blood cells get their ATP?

Glycolysis only… rememeber that it occurs in the cytosol- independent of the mitochondria

What is CRITICAL in the blood?

Maintaining blood glucose

Why is Gluconeogenesis important?

This is because it helps maintain blood glucose for the nervous system and RBCs

What are the three major substrates of Gluconeogenesis?

Lactate, Amino Acids, and Glycerol

What three major hormones regulate blood glucose?

Insulin, Glucagon, and Epinephrine

Where is insulin found?

The beta cells of the pancreas?

When is insulin released?

When blood glucose levels are high

What is the relationship between Insulin and Glucose?

Inversely Proportional

What happens to glucose after insulin in released?

There is an increased glucose UPTAKE by cells (this just means glucose is being mobilized to places where it can be utilzed by the cells)

What does insulin increae?

Glucose uptake, Glycogenesis, and Lipogenesis

What does insulin decrease?

Gluconeogenesis and glycogenesis

Where is Glucagon found?

It is found in the alpha cells of the pancreas

When is Glucagon released?

It is released when glucose is low (think Gluc GONE, so like make more)

What is the relationship between Glucagon and Glucose.

Directly proportional

What is the relationship between Insulin and Glycagon?

They do opposing actions

What does Glucagon increase?

Glycogenolysis and Gluconeogenesis

What is epinephrine released by?

The adrenal glands

In terms of time, how does Epinephrine compare to Insulin and Glucagon?

Insulin and Glucagon regulate in longer intervals, white Epinephrine is a rapid response

When is epinephrine usually released?

In fight or flight - when animals experience a need for a burst of energy

What does Epinephrine do?

Stimulate glycogen breakdown in liver and muscle

Who has higher blood leve;s between Ruminants and Monogastrics?

Monogastrics

What is the primary contributing factor to the reason ruminants have lower blood glucose levels than monogastrics?

The Ruminant’s Digestive System

What happens to glucose in monogastrics v ruminants?

Monogastrics: Formation of gluvose which is then absorbed into the liver

Ruminants: Carbs are fermented, and microbes get to it

In ruminants, what do the microbes ferment Dietary Carbs into?

SCFA - Short Chain Fatty Acids

What is the predominant way ruminants get their energy?

Gluconeogenesis, bc there is minimal direct glucose absorption

What organs/tissues require Insulin for Glucose Uptake?

Skeletal muscle, cardiac muscle, adipose tissue, and the liver

What protein is responsible for glucose uptake?

GLUT-4 (insulin dependent)

What organs/tissues DONT need insulin for glucose to be metabolized?

Brain, Red Blood Cells, Kidney, Intestinal mucosa, and Eyes

What is Hyperglycemia?

High Blood Sugar

What is Glucosuria?

Abnormal amount of glucose in urine

What is one of mechanisms to avoid high blood glucose levels that relates to Glucosuria?

Excreting glucose in urine

What is Polyuria?

Massive water loss; excess urination

What is Polydipsia?

Dehydration and excess thirst

Why does Ketosis occur?

Even though blood glucose levels are high, some certain cells cant mobilize and thus utilize that energy due to the absence or impairment of Insulin. Because of this, cells are in a “starving” mode and they get their energy in the forms of ketone bodies which come from fatty acids/

What is Ketoacidosis?

Excess Ketone production leads to a decrease in blood pH (b/c ketones are acidic)

What is Ketonuria?

abnormal amount of ketone bodies in urine

What is Hepatomegaly?

It is an enlarged liver (inflammation, infection, metabolic disorders)

What is cataracts?

Swelling, damage, and opacity to the eye caused by the drawing of water into the lens cells

Metabolic states reflect coordinated ________ _______ that shifts the body between fuel storage and fuel mobilization.

hormonal control