Histology of Cartilage and Bone

Histology Lab - Video 9: Cartilage and Bone

This video guides you through the basic histology of bone and cartilage.

Tissue and Cells looked at are:  Ground Bone, Demineralized bone (from human rib), Hyaline Cartilage, Elastic Cartilage from epiglotus, Fibrocartilage, Bone from Nasal Concha, Intramembranous ossification, Endochondral Ossification, Bone from infant finger

The learning objectives are:
1. Be able to identify the three types of cartilage: hyaline, elastic, and fibril and their subunits
2. Be able to identify Bone tissue and its sub-components





Courtesy of William Krause, PhD .
These videos will orient you to each cell and tissue type as well as prepare you for medical practice
Dr. Krause made these videos to help his class in learning and studying histology. Because of overwhelming demand, he would like to make them available world-wide.
Used and uploaded with full permission of William Krause, PhD (The Producer and narrator).

Dr. Krause is a member of the Department of Pathology and Anatomical Sciences at the University of Missouri. He has won several awards for teaching at the School of Medicine and is the author of many books including a study guide to go along with this video series:
http://www.amazon.com/Krauses-Essential-Histology-Medical-Students/dp/1581124686

Please be encouraged to visit Dr. Krause's webpage
http://web.missouri.edu/~krausew/Histology/Home.htmlhool.html

Histology of Muscle Tissue

Histology Lab - Video 8: Muscle Tissue

This video guides you through the basic histology of Muscle Tissue.

Tissue and Cells looked at are: Skeletal Muscle (longitudinal and cross-section), Motor-end plate preparation, Cardiac muscle, Smooth muscle in the gut and small artery.

The learning objectives are:
1.Distinguish the three types of muscle seen in the light microscope
2. Know the structural morphology of each muscle type




Courtesy of William Krause, PhD .
These videos will orient you to each cell and tissue type as well as prepare you for medical practice
Dr. Krause made these videos to help his class in learning and studying histology. Because of overwhelming demand, he would like to make them available world-wide.
Used and uploaded with full permission of William Krause, PhD (The Producer and narrator).

Dr. Krause is a member of the Department of Pathology and Anatomical Sciences at the University of Missouri. He has won several awards for teaching at the School of Medicine and is the author of many books including a study guide to go along with this video series:
http://www.amazon.com/Krauses-Essential-Histology-Medical-Students/dp/1581124686

Please be encouraged to visit Dr. Krause's webpage
http://web.missouri.edu/~krausew/Histology/Home.htmlhool.html

Histology of Integument

You will notice in this histology lab that it is described two-dimensionally as a cross-section of coiled up spaghetti. Check out the image (posted below the video) to see why. 

Tissue and Cells looked at are: Thick skin, Thin Skin, ductal systems and corpuscles in both, and specifically an axilla.

The learning objectives are:

1. Be able to identify the strata of both thick and thin skin

2. Recognize the morphological changes of Keratinocytes as they rise through the layers of the epidermis

3. list three other cell types that also occur in the epidermis

4. Be able to identify the two basic layers of the dermis

5. Be able to identify the appendages of skin and their subcomponents

This video guides you through the basic histology of the Integument System. 

This image is a three-dimensional depiction of the eccrine sweat gland. The photo is embedded from "HowStuffWorks" - an article entitled "Understanding Eccrine Sweat Glands"

Courtesy of William Krause, PhD . 

These videos will orient you to each cell and tissue type as well as prepare you for medical practice

Dr. Krause made these videos to help his class in learning and studying histology. Because of overwhelming demand, he would like to make them available world-wide.

Used and uploaded with full permission of William Krause, PhD (The Producer and narrator). 

Dr. Krause is a member of the Department of Pathology and Anatomical Sciences at the University of Missouri. He has won several awards for teaching at the School of Medicine and is the author of many books including a study guide to go along with this video series:

http://www.amazon.com/Krauses-Essential-Histology-Medical-Students/dp/1581124686 

Please be encouraged to visit Dr. Krause's webpage 

http://web.missouri.edu/~krausew/Histology/Home.htmlhool.html

Histology of Lymphatic Tissue

Histology Lab - Video 6: Lymphatic Organs

This video guides you through the basic histology of Lymphatic Organs.
Tissue and Cells looked at are: Jejunum (GALT), Illeum (Peyer's Patch, Crypts of Lieberkuhn), Palantine Tonsil, Adenoid, Lymph node, Spleen, and Thymus.

The learning objectives are:
1. Be able to identify and describe the histologic detail of a tonsil and be able to distinguish between tonsils
2. Be able to identify and describe the histological architecture of a lymph node
 - Trace the flow of lymph and blood through a lymph node
3. Be able to describe the histological architecture of the spleen
 - Trace the flow of lymph and blood through the spleen and relate it to spleen function
4. Be able to identify and describe the architecture of the Thymus
 - relate structure to function





Courtesy of William Krause, PhD .
These videos will orient you to each cell and tissue type as well as prepare you for medical practice
Dr. Krause made these videos to help his class in learning and studying histology. Because of overwhelming demand, he would like to make them available world-wide.
Used and uploaded with full permission of William Krause, PhD (The Producer and narrator).

Dr. Krause is a member of the Department of Pathology and Anatomical Sciences at the University of Missouri. He has won several awards for teaching at the School of Medicine and is the author of many books including a study guide to go along with this video series:
http://www.amazon.com/Krauses-Essential-Histology-Medical-Students/dp/1581124686

Please be encouraged to visit Dr. Krause's webpage
http://web.missouri.edu/~krausew/Histology/Home.htmlhool.html

Nucleotide Biosynthesis

Nucleotides are nitrogenous
Our bodies need nitrogen to make nucleotides
Our bodies produce nitrogenous waste when breaking down nucleotides



 - Breakdown of Purines produces Uric acid (a nitrogenous waste)
 - High levels of Uric acid can cause Gout
    - Uric Acid levels are increased when:
       1. Cell turnover is high (some kinds of cancer)
       2. Glucose is being overly-shunted into the Pentose Phosphate Shunt

The nomenclature of Nucleotides changes depending on whether a sugar is attached and if a phosphate is attached.

Two pathways for biosynthesis:
De-Novo (From scratch) – Used in growth
Salvage pathway (Recycling) – Used to maintain
THF is used for nucleotide synthesis by acting as a carbon carrier

Ribose-5-Phosphate from Pentose Phosphate shunt is converted to PRPP, which is converted to phosphoribosylamine
Phosphoribosylamine is converted to IMP
IMP can go down two pathways, making either ATP or GTP

Pyrimidines are formed from Aspartate and Carbomoyl phosphate (same as urea cycle)
 - Then PRPP is added (after the fact)
Carbomoyl Phosphate and Aspartate combine to form the Pyrimidine ring
 - The pyrimidine ring is added to PRPP to form Orotidylate,
- UMP, UTP are formed from Orotidylate
  - CTP is formed from UTP

The Urea Cycle

Big Picture:
An Ammonium Ion combines with Bicarbonate and Aspartate to form Urea
How is the Urea Cycle turned on and off? What might prevent the urea cycle from excreting Nitrogenous waste even when the amount of waste is very high?




The Control step:
Bicarbonate and NH4 Combine to form Carbomoyl Phosphate at the expense of 2 ATPs
Carbomoyl Phosphate Synthetase 1 (CPS1) catalyzes the reaction
  If N-AcetylGlutamate (NAG) is present then CPS1 is active
  NAG is formed by combining Acetyl-CoA with Glutamate
  THERE MUST BE LOTS OF ACETYL-COA OR THE REACTION WON’T HAPPEN
  Low energy state can prevent the Urea Cycle by not having acetyl-CoA

The Nitrogen Cycle

Muscle breaks down Amino Acids for energy. The Amine group is picked up and carried by Glutamine and Alanine to the liver or the kidney.

NH4 is excreted in the kidney when bicarbonate is low. Bicarbonate is needed in the urea cycle, but it is also needed in acid-base buffering.

Free Ammonia and Ammonia from  Aspartate will enter the urea cycle to form Urea.

Nitrogen Mobilization and Excretion

Amino acids can be used for energy production. They usually fall in one of two categories.
They are either:
+Ketogenic or
+Glucogenic

Several of them are in both categories.
Only Leucine and Lysine are strictly ketogenic.

When Amino Acids are used in these metabolic pathways, they give off Nitrogenous waste.
- How does our body maintain and regulate that waste?
- How do we prevent toxic levels of Ammonia from building up?





When an amino acid is used in the TCA or Gluconeogenesis (GNG), nitrogenous waste is created.
Three types of nitrogenous waste
  1. Amonia (comes from proteins and purines)
  2. Urea/Creatinine (Comes from only proteins)
  3. Uric Acid (Comes from only Purines)
The primary way of dealing with nitrogen is the urea cycle

Amino Acids are often used as carriers of Nitrogen to move them in the body without becoming toxic.
The two primary carriers are Glutamine and Alanine (Depending on where the nitrogen is being delivered to).

Vitamin B6 (Pyridoxal Phophate) is a required prosthetic for transamination. 

Introduction to Amino Acid Metabolism

An overview of the Amino Acid structure and metabolism




Theme:
Aspartate From Oxaloacetate
Glutamate From Alpha

Amino Acids do not always need to be produced
  - Most Amino Acids will negatively inhibit the committed step in their production
Protein Degradation adds to the Amino Acid pool.

Reciporical Control of Fatty Acid Synthesis and Oxidation

How is Fatty Acid Synthesis and Oxidation controlled? How do they not both occur at the same time?



Rate limiting step in FA Synthesis is the formation of Malonyl CoA by Acetyl-CoA Carboxylase (ACC)

ACC is down-regulated by Palmitoyl-CoA, PKA (Glucagon and Epinepherine), and AMP-Activated Protein Kinase

ACC is up-regulated by Citrate and Protein Phosphatase (insulin)

The breakdown of Fatty Acids is primarily regulated by Carnitine-Acyl-transferase (CPTI)
CPTI is down-regulated by Malonyl-CoA

Muscles will oxidize fatty acids when they need energy.
Muscles will produce Malonyl-CoA (but will not finish synthesizing fatty acids)
 - The purpose of producing Malonyl-CoA is to inhibit the Oxidation of Fatty Acids when energy is high

Fatty Acid Synthesis

How do we make Fat from excess sugar?



Glucose goes through glycolysis to pyruvate.
PDH is activated by insulin signaling. Acetyl CoA is combined with Oxaloacetate to produce Citrate.
Citrate moves out of the mitochondria via the Citrate Shuttle, and Acetyl CoA is reformed
Acetyl CoA is transformed to Malonyl CoA (Negative feedback prevents Beta Oxidation)

FA synthesis is produced by Fatty Acid Synthase – works as a dimer – Multifunctional protein
Steps in FA Synthesis:
  1. Condensation
2. Reduction
3. Dehydration
4. Reduction
REPEAT
Pattern repeats until you obtain a 16 carbon Fatty Acid chain
  8 Acetyl CoA + 7ATP + 14NADPH  YIELDS  1 Palmitate, 14 NADP, 8 CoA, 7 ADP

Of the 14NADPH needed, 8 come from Oxaloacetate being converted to Malate.
The other 6 Come from the Pentose Phosphate shunt

How Ketones are Made

Acetyl CoA should be combined with oxaloacetate to enter the TCA cycle.
When Oxaloacetate is unavailable or when the enzymes Citrate Synthase is deactivated, then Acetyl CoA cannot enter the TCA cycle. Where does it go?



Ketones are four-carbon molecules that carrie the acetyl group of acetyl CoA

Three acetyl CoA molecules are combined to make 3-Hydroxy-Beta-Methylglutaryl-CoA (HMG-CoA)
HMG-CoA is broken into a molecule of Acetoacetate (4 carbons) and Acetyl CoA (2 carbons)
NADH can reduce acetoacetate to Beta-Hydroxybuterate.

Acetone is created by the spontaneous decarboxylation of acetoacetate.  (Fruity breath)

Oxidation of Odd-Chain Fatty Acids

To make Acetyl CoA, you have to have two carbons. When fatty acids are oxidized, they are usually even-numbered carbon chains (8, 10, 12, 14, 16...). However, very seldomly, there are odd-numbered fatty acid chains. By definition, the last three carbons cannot be converted to acetyl CoA.
What happens to these?



When you get to a five-carbon fatty acid
- undergoes beta oxidation to AcetylCoA and Propionyl CoA
- Three more steps will convert Propionyl CoA to Succinyl CoA

- Succinyl CoA can contribute carbons to gluconeogenesis! (exceptions to the rules)

Beta Oxidation of Fatty Acids (Short, Medium, and Long Chain)

Beta oxidation is the breakdown of FAs to Acetyl Coa
Learn the steps in Beta Oxidation and how fats are moved into the mitochondria.

Clinical Correlation: What does a high level of dicarboxylic acid found in urine indicate about beta oxidation?



Primary FA breakdown is beta-oxidation
Secondarily – Alpha oxidation or omega oxidation

Long-chain fatty acids are broken down in the peroxisome first (before undergoing beta oxidation)

Major similarity of FA synthesis and Oxidation is the use of Co-enzyme A

Moving Long Chain Fatty Acids into the Mitochondria:
Long chain fatty acid converted to acylCoA by Acyl CoA Synthetase (1st enzyme)
Then Acyl CoA is attached to Carnitine by Carnitine Palmitoyl Transferase 1 (2nd Enzyme)
The Acyl Carnitine is transported through a Translocase (3rd Enzyme)
Inside the matrix, Acyl Carnitine is converted back to Acyl CoA by CPTII (4th Enzyme)
- An error in any of these enzymes can present as a beta oxidation deficiency

Steps in Fatty acid oxidation:
1. Attach FA to CoA
2. Medium and short chain transported into mitochondria – Long chain attached to carnitine
3. Move long chain acylcarnitine into mitochondria
4. Reform Acyl CoA
5. Acyl CoA + FAD yields Trans-enoyl CoA
6. Trans-Enoyl Coa + H2O yields hydroxyacyl CoA
7. HydroxyAcyl CoA + NAD yields Ketoacyl CoA + NADH
8. 3 Ketoacyl CoA + CoA yields Acetyl CoA and Acyl CoA (Shortened by two carbons)

Transport of Fatty Acids in the Body

How do Fatty Acids get from the stomach and intestines into the liver?
And how do they get from the liver to adipocytes?



-Absorbed as FA and monoacylglycerol into the mucosal cell
-In mucosal cell, it gets combined with other lipids and proteins into a chylomicron
- Transported via the lymph system

TRENDS in lipoprotein size and density
Chylomicrons, VLDL, IDL, LDL, HDL (in order of density)
As density goes up, the particle mass decreases and % protein increase, % Triglyceride decreases
Chylomicron transported to liver via lymph
From liver, LDL transports to other tissue
From peripheral tissue to the liver, HDL
Bile salts will dump some fatty acids into the intestines.

Palmitate is the primary FA produced by the liver. 

Stored in adipocites as triacylglycerols and protected by perilipin
Epinepherine signaling will phosphorylate Hormone Sensitive lipase and perilipin, allowing TAGs to be broken down into FFAs. 
Free fatty acids move into the serum and attach to albumin. 

NOTE: In the past research was inconsistent about whether or not glucagon acted on adipocytes to release FFA. Recent research has almost excluded this possibility by showing that in vivo, glucagon does not release fatty acids, but epinepherine and glucocorticoids do. However, glucagon has some effect on these two hormones.
Check this Glucagon article

Cholesterol Biosynthesis

A close look at the steps required to produce cholesterol and a clinical correlation on controlling cholesterol

Step 1: 3 Acetyl Coa à 3-hydroxy-3-methylglutaryl Coa (HMG Coa)
HMG-Coa à Mevelonate

Step 2: Mevelonate + CoASH  + 3ATP à Isopentenyl PPi

Step 3: Condensation of 6 molecules of isopentenyl PPi to produce Squalene

Step 4: Cyclization of squalene and conversion to Cholesterol

• Only a small fraction of cholesterol comes from diet. Liver production of cholesterol is five times higher than dietary intake.
• Cholesterol isn’t bad, too much is bad. It’s used to produce steroids and hormones in our body

Essential and Non-Essential fatty acids - introduction

What are the essential and non-essential fatty acids?
21-30% of fat stores are palmitate. Many other non-essential fatty acids are made from palmitate. Is Palmatate essential or non-essential?




Some fats, Linoleate (omega 3), linolenate (Omega 6) and their derivatives cannot be made by our body directly
Fats act as hormones, cell signals, and inflammatory pathway molecules

Basics of Triacylglycerols and Glycerolphospholipids

This is a review of the typical nomenclature of Fatty acids and
how triacylglycerols and glycerol phospholipids are synthesized

Histology of Connective Tissue

Go Back to "Histology Page" for more Histology Lab Videos

Histology Lab - Video 5: Connective Tissue

This video guides you through the basic histology of Connective Tissue.
Tissu and Cells looked at are: Fibroblasts, think skin, aorta, arteries, lymph nodes, lymphocytes, mast cells, adipocytes, thymus, macrophages, eosinophils, stomach, small intestine, infected eyelid, and foreign body giant cells (fused macrophages)

The learning objectives are:
1. Be able to identify and distinguish the three connective tissue fiber types
2. Be able to classify general connective tissues according to the arrangement of their fibers
3. Be able to distinguish and identify the following cell types (indigenous and transient cells): Fibroblasts, macrophages, plasma cells, fat cells (adipocytes) masts cells, eosinophils, neutrophils, lymphocytes.




Courtesy of William Krause, PhD .
These videos will orient you to each cell and tissue type as well as prepare you for medical practice
Dr. Krause made these videos to help his class in learning and studying histology. Because of overwhelming demand, he would like to make them available world-wide.
Used and uploaded with full permission of William Krause, PhD (The Producer and narrator).

Dr. Krause is a member of the Department of Pathology and Anatomical Sciences at the University of Missouri. He has won several awards for teaching at the School of Medicine and is the author of many books including a study guide to go along with this video series:
http://www.amazon.com/Krauses-Essential-Histology-Medical-Students/dp/1581124686

Please be encouraged to visit Dr. Krause's webpage
http://web.missouri.edu/~krausew/Histology/Home.htmlhool.html

Histology of Glandular Epithelium

Go Back to "Histology Page" for more Histology Lab Videos

Histology Lab - Video 4: Glandular Epithelium

This video guides you through the basic histology of Glandular Epithelium.
Cells looked at are: Small intestine (globlet cells, crypts of lieberkuhn, brunner's gland), Colon, Trachea, Stomach (goblet cells and pyloric glands), Skin (sweat glands and sebaceous gland), and submandibular gland

The learning objectives are:
1. Be able to identify glands according to their histological organization
2. Examine the intestinal epithelium for goblet cells (unicellular exocrine gland)





Courtesy of William Krause, PhD .
These videos will orient you to each cell and tissue type as well as prepare you for medical practice
Dr. Krause made these videos to help his class in learning and studying histology. Because of overwhelming demand, he would like to make them available world-wide.
Used and uploaded with full permission of William Krause, PhD (The Producer and narrator).

Dr. Krause is a member of the Department of Pathology and Anatomical Sciences at the University of Missouri. He has won several awards for teaching at the School of Medicine and is the author of many books including a study guide to go along with this video series:
http://www.amazon.com/Krauses-Essential-Histology-Medical-Students/dp/1581124686

Please be encouraged to visit Dr. Krause's webpage
http://web.missouri.edu/~krausew/Histology/Home.htmlhool.html

Histology of Barrier Epithelium

Go Back to "Histology Page" for more Histology Lab Videos

Histology Lab - Video 3: Barrier Epithelium

This video guides you through the basic histology of Barrier Epithelium. Cells looked at are epithelial cells from Stomach, Jejunum, Ovaduct, Kidney, Trachea, Epididymis, Esophagus, Thin and Thick skin, Ureter, and Submandibular gland.

The learning objectives are:
1. Be able to locate identify and classify the various types of epithelium
2. Be able to identify the various apical specializations and understand their functional connotations




Courtesy of William Krause, PhD .
These videos will orient you to each cell and tissue type as well as prepare you for medical practice
Dr. Krause made these videos to help his class in learning and studying histology. Because of overwhelming demand, he would like to make them available world-wide.
Used and uploaded with full permission of William Krause, PhD (The Producer and narrator).

Dr. Krause is a member of the Department of Pathology and Anatomical Sciences at the University of Missouri. He has won several awards for teaching at the School of Medicine and is the author of many books including a study guide to go along with this video series:
http://www.amazon.com/Krauses-Essential-Histology-Medical-Students/dp/1581124686

Please be encouraged to visit Dr. Krause's webpage
http://web.missouri.edu/~krausew/Histology/Home.htmlhool.html

Histology of Blood and Bone Marrow

Go Back to "Histology Page" for more Histology Lab Videos

This video is guides you through the basic histology of blood, bone marrow, and the many stages of hematopoiesis.



Learning objectives are:
1. Be able to distinguish formed elements in the peripheral blood
2. Understand the relationship between the numbers observed and their functions
3. Be able to distinguish the various stages of maturation associated with erythropoiesis.
4. Understand what the morphological changes signify during the transformation.
5.  Be able to distinguish the various stages of maturation associated with granulocytopoiesis
6. Understand the morphological changes between the mature granulocytes
7. Be able to recognize megakaryocytes and platlets, and understand thrombocytopoiesis.
8. Be able to identify monocytes, lymphocytes, and plasma cells and have a basic understanding of the inter-relationship of these cells

.


Courtesy of William Krause, PhD .
These videos will orient you to each cell and tissue type as well as prepare you for medical practice
Dr. Krause made these videos to help his class in learning and studying histology. Because of overwhelming demand, he would like to make them available world-wide.
Used and uploaded with full permission of William Krause, PhD (The Producer and narrator).

Dr. Krause is a member of the Department of Pathology and Anatomical Sciences at the University of Missouri. He has won several awards for teaching at the School of Medicine and is the author of many books including a study guide to go along with this video series:
http://www.amazon.com/Krauses-Essential-Histology-Medical-Students/dp/1581124686

Please be encouraged to visit Dr. Krause's webpage
http://web.missouri.edu/~krausew/Histology/Home.htmlhool.html

Histology of the Cell

Go Back to "Histology Page" for more Histology Lab Videos

This video is the introduction to Histology Laboratory series. It shows how to approach histology as well as looking at the histology of some larger cells including oocytes, neurons, and intestinal epithelium.




The learning objective is to be able to identify the:
1. Nucleus
2. Nucleolous
3.Nuclear Envelope
4. Cytoplasm
5 Mitotic Figures

Courtesy of William Krause, PhD .
These videos will orient you to each cell and tissue type as well as prepare you for medical practice
Dr. Krause made these videos to help his class in learning and studying histology. Because of overwhelming demand, he would like to make them available world-wide.
Used and uploaded with full permission of William Krause, PhD (The Producer and narrator).

Dr. Krause is a member of the Department of Pathology and Anatomical Sciences at the University of Missouri. He has won several awards for teaching at the School of Medicine and is the author of many books including a study guide to go along with this video series:
http://www.amazon.com/Krauses-Essential-Histology-Medical-Students/dp/1581124686

Please be encouraged to visit Dr. Krause's webpage
http://web.missouri.edu/~krausew/Histology/Home.html

UnCoupling Protein (Thermogenin) Heat Production and ETC Poisons

In Brown Adipose Tissue, Hydrogen Ion (Proton) movement can be uncoupled from the production of ATP. So, instead of using the high energy of the electro-chemical gradient to produce work (by making ATP), the energy is released as heat.

 -In this video, the uncoupling protein known as Thermogenin is looked at very quickly and the biochemistry of it's control is investigated.
- This video also explores other irregularities in the Electron Transport Chain that uncouple electron flow from ATP-Synthesis, such as respiratory poisons.

From Pyruvate to Acetyl-CoA in Four Steps

How does Pyruvate Dehydrogenase (PDH) convert Pyruvate into Acetyl-CoA?

This video explores the four steps involved in producing Acetyl-CoA and NADH from Pyruvate and NAD+
1. Decarboxylation of Pyruvate
2. Reduction
3. Oxidation
4. NAD+ Reduction

Seperoxides during Ischemia and Reperfusion

The Electron Transport Chain Donates A Pair of Electrons to O2, thus producing two molecules of H2O. What happens when Oxygen is limited or in low supply (Ischemia)? What happens when Oxygen supply is restored (reperfusion)?


When Oxygen availability is extremely low (Ischemia), electrons get backed-up in the ETC. And when an oxygen molecule is nearby, single electrons may "leak/jump" onto that oxygen molecule inappropriately. This produces Superoxides (oxygen radicals). In the same vain, when oxygen is restored to the cell (reperfusion), the over-crowded electron transport chain will unload single electrons onto oxygen, creating many superoxides. This continues until the ETC re-equilibrates. This is known as reperfusion injury. 

Respiratory Control of the Electron Transport Chain (ETC)

Some Protons move through a symporter, which moves Phosphate into the Mitochondrial Matrix. The rest of the protons are typically moved through ATP Synthase.
When ATP is transported out of the mitochondria, ADP is simultaneously transported into the Mitochondria (The ATP-ADP Antiport).  When ATP is not used by the cell, there is no ADP available to antiport with ATP. So, ATP becomes backed up in the mitochondria.


- In this video, we explore how the electron transport chain is connected intimately with the production of ATP. This is known as respiratory control. When ATP is not exported from the mitochondria, what happens to the TCA cycle and ETC?

NADH/FADH2 (Electron) Movement into the Mitochondria

Electrons are Donated to the Electron Transport Chain from NADH. However, NADH that is produced in the cytosol cannot move directly into the Mitochondria. In order to overcome this barrier, our cells use two different mechanisms to move Electrons into the mitochondrial Matrix


- In this video the Malate-Aspartate Shuttle is looked at for its' role in transporting NADH and the Glycerol-3-Phosphate Shuttle is looked at in it's role of converting electrons on NADH into Electrons on FADH2, which can be donated directly to CoQ. 

Introduction to the Electron Transport Chain (ETC)

   The Electron Transport Chain is used for oxidative Phosphorylation of ADP to form ATP. This is done by Electrons which are donated from NADH and FADH2 into the Electron Transport Chain. Energy from these electrons are used to pump Hydrogon ions (protons) across the inner membrane. The Electro-chemical Gradient produced is then used to power ATP-Synthase. The protons moving through the synthase produce a "Proton-Motive-Force" which powers the addition of an inorganic phosphate onto ADP, producing ATP.

- This video explores the sequences of the electron transport chain, the protein subunits, and the prosthetic groups used to transport electrons.

Pyruvate Regulation in the Starvation State

   During the Starvation State, the Liver attempts to produce Glucose for the rest of the Body. The primary source of Carbon Molecules in these new glucose molecules comes from Amino Acid Skeletons, while the Primary Energy source in the Liver is from the Oxidation of Fatty Acids into Acetyl-CoA
   To prevent Pyruvate from forming into Acetyl-CoA, the Cells have to use allosteric inhibition to stop Pyruvate Dehydrogenase (PDH) from acting on Pyruvate.

- This video explores the source of Pyruvate and Reducing Equivalents in the TCA cycle of the liver during the starvation state.
- This Video Also Explores Allosteric regulation of PDH

Anaplerotic Reactions Replinish TCA Intermediates

Anaplerotic reactions are reactions that replinish intermediates in a biochemical cycle. In the TCA cycle, Anaplerotic reactions replenish intermediates such as Succinyl CoA, Oxaloacetate, Malate, and others.


-This video explores the difference between Anaplerotic reactions and Cataplerotic Reations. Pyruvate is explored in three anaplerotic reactions producing either Acetyl CoA, Oxaloacetate, and Alpha-Ketogluterate
Odd Chain Fatty Acids can contribute to Anaplerotic reactions such as Triheptanoin conversion to Succinate.

Introduction to the TCA/Kreb's Cycle

The TriCarboxylic Acid (TCA) cycle, also known as the Citric Acid Cycle (CAC), or the Kreb's Cycle, is used extensively in every cell to produce electrons for the Electron Transport Chain (ETC).


 -This video looks at the sources of Acetyl-CoA, which feed into the TCA cycle, as well as various enzymes involved

The Fate of Pyruvate - and the theory of Atkins diet

The fate of Pyruvate are determined by the relative concentration of several downstream products as well as hormonal regulation. Oxaloacetate is an important downstream product of Pyruvate.
This video explores how Pyruvate is controlled via signalling to the enzyme Pyruvate Dehydrogenase. It also explains how the Atkins diet is supposed to work, by keeping insulin levels low, you decrease the amount of fatty acid synthesis.