Bio(SUCKS!!!)Notes

Exam #2 – Spring ’97 Semester

Biology 1710.001 & .002

(who else would be this crazy to type up all these notes and then POST them for everyone to have?)

Beginning notes and the usual:

Well, we’re all back for the Spring ’97 Semester for more fun BIO!!! (Well maybe not all of us…) I’ll get my usual greets out in a minute after you read all the standard disclaimer stuff. And by the way, stop spending all your time trying to figure out the greets – you’re SUPPOSED to be STUDYING!!!!

Note to the reader: These notes, as weird as it may seem, are NOT a substitute for going to class or reading the text. Although they are probably cooler than any bio book that you’ve ever read, that STILL doesn’t mean that you can not go to class and then read these the day before the test and know everything. THAT WILL GUARANTEE YOUR FAILURE. (Gee… I wonder where you’ve seen something like THAT before…? Try the inside cover of your Frankenstein CLIFF NOTES… J )

P.S. I have taken these notes directly out of the reserve notes and added some stuff from the lecture. Unlike other people, I have NOT taken the liberty to put stuff in here from the book. That’s just a waste of time, especially since Dr. Sinclair and Dr. Donahue both TOLD US that the tests would be coming right out of the LECTURES. So, have fun. If you don’t understand anything (like the jokes about certain things), don’t worry about it. OK… OK… if you don’t understand the MATERIAL, then READ THE BOOK!!! Ohh yeah… be sure to know all the diagrams, too… they’ll be out to get ya… Good Luck!

One important Public Service Announcement by Dr. Sinclair:

There is a DISTINCT difference between PHYSIOLOGY and ANATOMY. In definitions:

PHYSIOLOGY is the study of HOW things function, as opposed to..

ANATOMY, which is the study of just the PARTS (like what Dr. Ghosh was basically teaching…

A bunch of names, but no use… WHO REALLY CARES???)

Nutrition – What REALLY is in food?

Here was Dr. Sinclair’s little PIZZA example… From all the stuff that are on the pizza, you get a bunch of different MACROMOLECULES ("big" molecules), which in turn are ground up into smaller MICROMOLECULES ( don’t tell me that you didn’t know that MICRO means SMALL…) That is the whole goal of DIGESTION: to take these MACROMOLECULES and turn them into things that we can use.

Here’s a list of what stuff goes to what"

Protein è Amino Acids è Proteins and other Hormones

CHO (Carbohydrates) è Simple Sugars (primarily GLUCOSE) è NRG!

Fat è Lipids è Cell Membranes (remember all that from Dr. Mariache? Queen of Proteins??? J )

(Oh yeah… just remember that CHO’s that are NOT used up can be turned to fat, lipids, etc.)

See Page 802 – A Diagram of the Digestive System

Digestion

Chewing (a.k.a. Mastication… hmmm… funny little word… J )

Digestive enzymes work only on the SURFACES of food particles, especially fruits an vegetables. (This is why it’s so important that the digestive (DI) tract has so many villi, and thus more surface area!!)

OK… so you eat this piece of pizza (hopefully NOT Papa John’s, because Papa John’s SUCKS!!! Go get some PIZZA HUT or something… J ). The first part of the digestion process is using your teeth, or CHEWING it.

The teeth up front, called your incisors, can exert up to 55 lbs. of pressure (ever try biting your hand off? Trust me… you could do it if you tried…)

The teeth in the BACK are called your molars. (As if you already didn’t know that… it’s not like you’re gonna be a DENTIST, are you???) These can exert up to 200 lbs. of pressure, and are used to GRIND the food down into little bits and pieces. (This is the part where you remember your mom telling you to CHEW your food x amount of times, but you didn’t really care… You were eating MACARONI and CHEESE!!!)

The Chewing REFLEX – this is technically the "alternation between relaxing the (lower) jaw and making it stiff again". It’s what moves out teeth! This is something we don’t really THINK about. (Well, you could try, but then it would start getting tough. Go ahead… try THINKING VOLUNTARILY to tell yourself to chew. Kinda gets tiring… doesn’t it… J Not only that, but now you look like a fool in front of all of your friends.)

Salivation (a.k.a. drooling, saliva, etc. and the whole bit… ) – When you chew the food (actually, it’s called a bolus, now that it’s a sloppy bunch of wet goo…), you mix it with saliva which is made in four different glands:

Parotid – secretes serous, a "watery" secretion that has an enzyme called "amylase" (an enzyme that breaks down starch, etc.)

Buccal – secretes mucin. (meaning "mucous-like). It aids in lubrication of the "bolus" down the tube and stuff…

Submaxillary or Sublingual (means "under tongue" – remember the Spanish word for tongue? It’s LENGUA, just as it is for LANGUAGE – a "tongue") – secretes a "mixed" secretion (has both of the above stuff).

The TOTAL amount of secretion in one day ranges from about 800 to 1500 ml of saliva a day… that a LOT of "spit". (Just think about making a one gallon jug of this stuff in one day and carrying it around… YUCK!!!)

The pH range of saliva is anywhere from 6.0 to 7.4

See page 803 – Diagram of the esophageal peristalsis

Saliva actually takes an important role in dental hygiene (here’s all that dentist stuff again…)

it "washes away" bacteria in the mouth (where it goes down to the stomach and is killed by all that acid down there…)

has "lysozyme" that DESTROYS bacteria. (Remember what a lysozyme does again? It BREAKS DOWN the cell wall of certain "stuff")

it also DIGESTS all the little bits of food that might get left behind in the mouth. This is an added bonus, because not only does it destroy all that nasty rotting food in your mouth, but it makes SURE that the extra bacteria in your mouth does have any substrate, or stuff that eat can eat and give you bad breath. That’s why you hear about the condition called "halitosis", where there isn’t enough saliva, and now your breathe really stinks, ESPECIALLY after eating. Then it’s REALLY bad… I’m sure you know of SOMEONE who might have this… or have at least SMELLED it… (UGHHH….)

What’s the cause? It’s the great autonomic nervous system:

There are two parts to the AUTONOMIC nervous system (don’t have to know what that means… just know it…) Salivation is controlled by the parasympathetic nervous system: which means that salivation is stimulated by:

taste (especially sour objects)

round objects (not really round, but SPHERICAL)

The "appetite" area of the brain and irritating foods in the stomach can ALSO stimulate it. (Hmm… that CATAVINI that I had at lunch wasn’t too great…)

Ohh yeah… it’s also stimulated while you’re running to the toilet after THINKING about that Catavini. You get nauseated, and then you go to the bathroom and HURL!

Swallowing (a.k.a. Degulation -- don’t ask… it’s from the reserve notes…)

Here’s the Voluntary Stage of swallowing – The tongue squeezes the bolus of food upward and backward into the pharynx against the palate. (Just one simple step – this is the only part that you really have to "do"… just think about swallowing, and it’s done…) This initiates the INVOLUNTARY stage of swallowing:

The Pharyngeal or Involuntary Stage:

Food stimulates receptors in the pharynx

The soft palate (above) moves upward and closes off the passages to the nasal cavities so food doesn’t go up there. (Mind you, sometimes this doesn’t work to well… I’m sure ASIAN people can recall AT LEAST once in their life when they had rice stuck up in their noses because of this. The only way to get it out is to blow your nose… J )

Vocal chords are pulled upward and back, so the epiglottis covers the larynx so food can’t enter the trachea. (i.e. You don’t choke on a piece of steak and die…)

Now there’s ANOTHER cause/effect thing: You start to choke when food goes "down the wrong tube". Or rather, when food blocks the trachea – the passage that leads down into your lungs. Then, you can’t breathe. Because this blocks your air, you can’t SPEAK either. So, you know when one of your kid siblings is faking that he or she is choking when they start to say, "HELP! I’m CHOKING!!!" You couldn’t breathe, even if you tried! The Heimlech maneuver simply applies pressure to the remaining air in your lungs to force out the food that’s stuck… simple, eh?

The esophagus (tube where food goes down to the stomach) opens up.

The pharynx contracts, propelling food into the esophagus. This constant, propulsive movement of the food / bolus / chime by a "wave" of muscles is called peristalsis.

The stomach muscles begin to relax (this is called Receptive Relaxation).

The lower esophageal sphincter relaxes, and the food empties into the stomach.

Note that this should CLOSE when the food is done emptying. If not, then the acid crap in your stomach can actually come back UP into the esophagus and damages it and the larynx. (They’re not protected against the gastric juices (HCl) like the stomach is… more on that later.) I think this is the cause of "heartburn" (although I don’t have it…)

The STOMACH!!!

The stomach is a STORAGE AREA for food until it is emptied, little by little, into the small intestine.

It’s also where the bolus is mixed w/ gastric juices for digestion.

The stomach can store about 1.5 quarts of "stuff". (Notice that it’s in QUARTS now… not pounds. The stomach is VOLUME dependent…)

The gastric glands in the stomach secrete two different things:

Parietal cells secrete the acid (HCl)

Chief cells secrete the enzymes (Pepsinogen)

Weak contractions of the stomach mix the food and propel it toward the duodenum (first stretch of the small intestine). (You can probably hear this movement if you listen really closely right after a big meal.)

The bolus of food, now mixed with acid, is referred to as acid chyme. (That’s basically vomit… It really sucks… AHHHH!!)

Hunger pangs are contractions that are probably due to low blood sugar.

Gastric emptying is the process of holding, mixing, and relaxing chyme into the duodenum.

See Page 805 – Diagram of the stomach, liver, and more fun, gooey stuff…

How is Gastric Emptying Controlled?

What is it that DECREASES gastric emptying?:

When the small intestine is full, a hormone called enterogastrone is released, telling the stomach, "STOP IT ALREADY! If you keep sending me more stuff, I’m gonna hurl… LITERALLY!!!)

Unprocessed proteins (ones that don’t really get broken down into their representative amino acids while in the stomach and are greater than 1 mm³ in size) ALSO slow down the gastric emptying process. (Remember when your mother said to chew your food 47 times before swallowing? This is "supposedly" how it helps…)

When the small intestine gets really STRETCHED out (not STRESSED…), this is called a "duodenal stretch", and tells the stomach, "Hey! STOP! I got something to work on! STOP IT!!!"

Acidity also plays a role. When the stuff in your duodenum gets really acidic, it’s just another sign that things need to get digested, etc. (I guess… I dunno… I was falling asleep…)

Fat also slows down the gastric emptying, just because it is SOOOO hard to digest.

OK… great… What can I do to INCREASE gastric emptying?:

First there was duodenal stretch… now there’s gastric stretch. When there’s tons of stuff in the stomach, things have to move along quickly, so more stuff is emptied in less time into the duodenum… or better yet, INCREASED gastric emptying.

The hormone gastrin – it is produced when you first start eating and is used to signal the stomach to get ready.

Fun with GASTRIC SECRETIONS (Aren’t they YUMMY???)

Gastric glands secrete the following stuff:

Hydrochloric Acid – it breaks down connective tissue (like steak… muscles are all connected, so you gotta break it all up)

Gastrin – controls the outlet of HCl to bolus to digest down the chyme.

Pepsinogen – broken down to pepsin by acid, and is them used to further digest proteins.

Intrinsic Factor – this allows you to absorb vitamin B₁₂, something that is absolutely essential for the creation of cell membranes.

è The MOST essential use of B₁₂ is for building the membranes of RED BLOOD CELLS. If these RBC’s can’t be produced, then you will get "pernicious anemia", in which the stomach cells are all killed off because they aren’t near any blood. Then, you die… J

Mucus – protects the stomach from enzymes and acid. (If you don’t have enough of this, you may just end up getting ulcers, which is essentially your stomach digesting ITSELF.)

Lots of fun with ACID SECRETIONS

Gastrin stimulates acid secretion

Neural control stimulates acid secretion also… stretching the stomach, for example.

Even more fun with PEPSINOGEN SECRETION

It is stimulated by acid in the stomach.

Neural control via the vagal nerves (I have no idea… never talked about it in class…)

Sequence of Events:

Stretch à Gastrin à HCl acid

Gastrointestinal stretch – stomach gets stretched (i.e., you eat, and you’re full)

Gastrin – this hormone produce, which makes gastric emptying go on

HCl acid produced – to digest the food in your stomach before it is emptied.

(Remember that this gastrin can also be produced by the stimulation of the appetite area of the brain. Remember that experiment where dogs salivated

at the sound of a bell? That’s a perfect example…)

Gastrin à HCl acid à Pepsinogen à Pepsin à Break down of proteins to Amino Acids

Gastrin – produced as a result to stretch, control outlet of acid

HCl acid – breaks down the…

Pepsinogen – to make…

Pepsin – which is used to…

Break down proteins into amino acids - (‘nuff said…)

Pathophysiology ("Patho" means bad or being bad, while physiology is "how things work". Now that totally means "something’s wrong with how things work". Just take the word "psychopath", for example. That’s something wrong with your mind… (you’re a PSYCHO!))

Gastritis is an inflammation of gastric mucosa. Alcohol and aspirin can penetrate the mucosal barrier so that your own gastric juices (HCl… a.k.a. hydrochloric acid) can hurt your stomach. You can get some REALLY big ulcers, and hence, digest your own stomach… (And in the words of Dr. Donahue, "…Then you die…!")

Peptic ulcers (most commonly found type of ulcer) usually occur in the first few inches of the duodenum when digestive juices get past the mucosal barrier. This MAY be caused by Heliobacter pylori (they keep finding this stuff in the ulcer area after an autopsy). Now you’ve got HOLES in your stomach.

Fun Fact (well… I don’t really think it classifies as fun, but it’s a FACT…): If there is blood in your stool (feces), then that’s a SURE sign of ulcers. Blood turns BLACK after being digested. You get the picture…

5. The SMALL INTESTINE! (Yippee Fun!)

Remember that the duodenum is the first few inches of the small intestine.

Recall that peristalsis is the propulsive movement from a "wave" of muscles, from mouth to anus. When stuff gets to the small intestine / duodenum, then a different movement occurs. This is called segmentation, where a "mixing" type of movement occurs.

This is controlled by the gastroenteric reflex (when the stomach is stretched, you get a movement called borborygmi – something you can hear. EMT’s use this to find out if victims are still living) Increased motility can be brought about via the hormones gastrin, insulin, and after eating.

Pancreas

Located parallel to and beneath the stomach.

The pancreas produces pancreatic fluid that has:

enzymes – which aids in the digestion of proteins, carbohydrates, and fat

bicarbonate fluids (that are alkaline) – neutralizes acid (just like how you pour bicarbonate powder on acid spills in chem lab… not like we ever do…)

Pancreatic juice is released in response to chyme in the duodenum.

Two hormones aid in the signaling and secretion of the two fluids:

cholecystokinin (CCK) – causes the release of enzymes

secretin – causes the release of the bicarbonate solution

BOTH of these hormones are produced in the duodenum.

Liver

Stores blood in times of excess volume. (EX: in case of injury, blood is let out so you don’t bleed to death… well… bleed to death AS FAST anyway…)

Has TONS of blood. So, if someone shoots you with a gun in the liver, "then you die!"

Metabolic functions of the liver:

stores glycogen (Glycogen is made when there is an excess of glucose. Insulin is the primary hormone that allows for this to happen. That’s why if you’re diabetic, you need to take insulin shots… the extra glucose comes out in the urine, rather than being stored)

Converts carbohydrates and proteins to FAT (if ever so needed… get off your butt and EXERCISE!!!)

Produces cholesterol. Remember that cholesterol, even though it’s been given a bad rap, is IMPRORTANT because:

it provides a basis for bile salts

it is an important component of cell membranes (if you don’t have any of this, you can freeze to death a whole lot faster!)

Secretory functions of the liver:

Bile salts – they are like detergents: they emulsify fats. (i.e. turn them in to tiny droplet size molecules known as micelles)

Bile salts are secreted into the gall bladder.

Either lots of fat or CCK stimulates the contraction of the gall bladder, to secrete the bile into the duodenum.

Contraction of the gall bladder has also been proven to be stimulated just by sight (your mouth watering at the sight of steak, etc.)

Enzymes from other places can also be released via this method.

DRUGS (don’t use ‘em)

The important point here is that drugs are metabolized here in the liver. They are conjugated in the liver with the bile from the gall bladder to make them water soluble, so you can "pee" the drugs out… J

Absorption in the Small Intestine

Intestinal mucosa (the squishy linings of the inside of the small intestine) is folded over and over again to increase the surface area by 3 times.

Villi, little hairs on the surface of the intestinal mucosa, increase the surface area by 10 times.

Microvilli (a.k.a. brush border), even SMALLER hairs on the villi, increase the surface area by 20 times.

(NOTE: This all comes back to the fact that digestion can only occur when the SURFACE AREA of the food is in contact with the SURFACE AREA of the intestine, etc. The key word is SURFACE AREA!)

Another "reason why": The reason why the intestine is so long is to give it more SURFACE AREA – the longer it is, the more chances there are to reabsorb stuff back into the body, and get the most out of the cavatini that you ate the other day.

The total increase of surface area (when you multiply it all out) comes out to 600 times the original surface area. If you spread that all out, then it’s about the same surface area as a tennis court. (Pretty impressive, eh? Don’t believe me? Try it out on your calculator… You don’t need derivatives…)

In the process of digestion, about 7 – 8 liters of water are reabsorbed back into the body. Keep in mind that the TOTAL capacity of the small intestine is about 20 liters.

Remember all those things that came out of Dr. Sinclair’s pizza example? Here’s how they break down and are taken in:

Carbohydrates are broken down into simple sugars (usually glucose), and taken in via active transport

Proteins are broken down into peptides or amino acids, and are reabsorbed, also, by active transport.

Fatty acids and monoglycerides are broken down into micelles with the help of bile salts, and then diffuse out through cell membranes. These micelles are then converted into chylomicrons (which, when covered with proteins, are now water soluble) and return to circulation via the lymph.

See page807 – Diagram of the structure of the small intestine

Large Intestine

The upper, beginning (proximal) portion absorbs even more water and (dissolved) salts from the chyme going through.

The lower, last portion of the large intestine, however, is primarily used for the storage of fecal matter until defecation occurs.

Movements are very sluggish. (The fluid in that acid chyme is quickly being reabsorbed back into the body, so the "solid" portion is what is moving through.)

Haustrations are mixing movements that mix around the "mush" in your large intestine. They usually last anywhere from about 30 to 60 seconds.

The "propulsive" movements (so to speak) are called mass movements that occur a few times a day, or once a day. (i.e. whenever you go to the bathroom).

Gastric and duodenal reflexes stimulate these mass movements. (If you eat more and you are already full, you’ll need to move NOW!)

10. Defecation

The rectum is usually empty of feces... (well.. in most cases anyway...)

Mass movement (you know what I’m talking about...) forces feces into the rectum... Then you can "feel it". (Hehehehe...) This stimulates the DESIRE for defecation. (Well... I really wouldn’t call it desire... it’s more kinda like, you HAVE too...)

When you’re REPUBLICA ("Ready to go..."), the rectum contracts, and both the internal AND the external anal sphincters relax. (Yes... you have two of them...)

That’s what TOILET TRAINING is all about - the relaxation of the anal sphincter is an INVOLUNTARY reflex that occurs when mass movements begin to occur. It’s the VOLUNTARY part, learning how to control the EXTERNAL anal sphincter, that you learn how to do early in life. (Well.. at least you BETTER learn!!!)

There aren’t any villi in the large intestine, by the way... Instead, there’s lots of mucus for... uhh.... err.... let’s just say "lubrication". (Is all of this grossing you out yet?)

Diarrhea refers to the irritation of the large intestine, usually by bacteria. (Eat any bad food lately? That’s where you get it from... like something doesn’t "agree" with you? That’s all it is... It stimulates the secretion of extra water and salts to wash the irritant away. (That’s why it’s really WATERY...)

Feces actually consists of 75% water and 25% solid.

The SOLID portion of feces consists of:

30% dead bacteria

20% fat

20% inorganic matter (I dunno...)

30% undigested fiber (remember. There is absolutely NOTHING on this earth that is living that can break apart plant cellulose. Even though plants make it, even PLANTS can’t break it down. THEY’RE SO STUPID!!!! They make cellulose when they have too much starch, etc. to store, and now they can’t do squat with it! HA!)

The brown color in feces is due to bilirubin, a pigment derivative of hemoglobin (dead Red Blood Cells (RBCs) are actually killed off this way, I think...)

The distinctive "odor" of feces comes from bacterial action... (Ughhhh....)

Constipation can be caused via very "psychological" means, especially during toilet training as a kid. If you start thinking that you need a certain time, and a certain place, and all that other good stuff just to take a shit, the feces will get held up inside for a long time. This can make the large intestine continue to reabsorb the water in the feces until there is virtually none left. This is otherwise known as MEGACOLON—the consistency of the feces can actually turn as hard as concrete... OUCH!!!! Then you take chocolate covered EX-LAX, which actually disturbs the lining of the large intestine and makes it watery, and you’re all better, right? Uhhh... I dunno... never happened to me....!!!! :)

Vomiting occurs when the GI tract becomes irritated, over distended, or overexcitable. (Must’ve been the cavatini!!!)

The vomiting center in the brain is stimulated, and you get anti-peristalsis... (you PUKE!) The stomach is squeezed between the diaphragm and abdominal muscles... (And as a result, anything inside goes up the esophagus and out into the toilet... hopefully... if you’re that lucky...)

Nausea is the conscious recognition of stimulation of the vomiting center... like when you’ve got motion sickness...

Flatus occurs from swallowed air, gases from bacterial action, and gas diffusing out of the blood. (Really explosive stuff… it has methane, hydrogen and CO₂ from bacterial action!!)

Gas in the stomach is nitrogen and oxygen… this results in a belch (burp… etc…)

Some gas in the small intestine is a result of the neutralization of acid

About 0.6 liters of gas are expelled each and every day! (Did you know that cows belch out enough gas everyday to power a home for a few days? Definitely a test questions, so KNOW IT!!!)

Physiology of the Kidneys

Bio(sucks) 1720 February 17-24, 1997 (Really?)

Richard J. Sinclair, Ph.D., D’Man, HeD, DooD

Hmmm… what do the kidneys do?

The major purpose of the kidney is to regulate the volume & composition of your major bodily fluids (like your blood for example…)

Welcome to Primordial Soup: See… life evolved and developed in a "high potassium" environment (remember all that stuff you learned in 9^th grade bio? Here’s where it’s gonna come in handy…). When life finally evolved (whatever it was…) the earth and land around the primordial soup eroded inward, and then there was a high amount of sodium surrounding the "life". HENCE, now, a bunch of K⁺ ions start inside the cell, and the Na⁺ stuff is outside, in the blood. IF this balance is not kept, things will go into reverse, and, in the words of Dr. Donahue, "… then you die…!"

SO, the next function of the kidneys is to eliminate metabolites and toxic substances from the body. It filters all of this out of the blood.

Somehow, the kidneys also regulate blood pressure, simply by removing the sodium ions (Na⁺) from the blood (now that the sodium is aqueous), thus lowering the blood pressure!!! (Remember from Dr. Donahue: If blood pressure goes to low, then not enough blood is getting everywhere, "then you die!". If it gets too high, then the heart can’t handle it anymore, and then it stops (it needs a rest!!!), "then you die!!!"

The primary component of kidneys (the "working" part, anyway) are the nephrons. These nephrons work to do all the filtering. You start off with 1.25 million nephrons per kidney. If things go bad (you do drugs a lot, kidney disease), you loose a whole bunch of these "then you die!" The problem is that you don’t KNOW if your kidney’s dying until 60% of the nephrons are gone. (If you REALLY wanna see how it works, see page 887.)

How do they work?

25% of the cardiac output (stuff coming out of the heart directly – this percentage of blood) is filtered at the glomerular capillaries.

This produces a total of 180 liters of "stuff" per day of filtrate, 99% of which is actually reabsorbed back into the blood stream. (Note: But usually we only piss out 1 L of urine a day… hmmm… know that the excess actually goes BACK into the blood stream… yuck…)

PLASMA is actually what gets processed in the kidney. Out of a 5 liter sample of blood, there are 3 liters of plasma. This plasma is reprocessed over and over.

65% of what is left over is filtered in the proximal tubule. It’s the "proximal" tubule because it’s closer to the heart. It is twisted & curved, like the small intestine, so there can be good reabsorption (there are lots of little villi).

25% of what’s left is filtered in the Loop of Henle.

10% of that is filtered in the distal tubule and collecting duct.

1 ml per minute of urine is produced

What’s in blood?

Blood cells, proteins, and other "large things". (Hmmm…)

Water

Salts

Metabolically important substances (like glucose, amino acids, fatty acids, etc. and other stuff that you get from that same PIZZA… or Cavatini… whatever the case may be…)

What’s in URINE?

All glucose, fatty acids, and amino acids are reabsorbed in the proximal tubule… none in the urine.

99% of the salts get reabsorbed, which takes water with it via osmosis.

Additional water is reabsorbed in the collecting duct.

Metabolites are not reabsorbed well… Some are secreted. (i.e. penicillin, hydrogen ions) into tubule, concentrated and excreted.

Concentrated or dilute urine? (Why does it differ?)

When body fluids are concentrated, a hormone from the pituitary gland, called an antidiuretic hormone, increases reabsorption of water from the collecting duct, which concentrates the urine.

Diuretics prevent reabsorption back into the blood, and the salt is excreted, carrying out water.

Alcohol prevents release of antidiuretic hormone. As a result, you get diluted urine.

 

The major FUNCTION of the circulatory system is to transport blood so that oxygen and glucose & other nutrients to each cell and so that waste products (like CO₂) can be eliminated from the body.

Every cell needs to be no further than 1mm away from blood supply.

It is also used to get waste out. (Like when you breathe out). Stuff like CO₂, ammonia, and other stuff…

The Vessels:

Arteries – no matter what KIND they are, they carry blood AWAY from the heart (be it oxygenated and deoxygenated blood!) (Remember: artery starts with "A" – A for AWAY!!!

Areterioles – Smaller branches of the arteries.

Capillaries – absolutely tiny. This is where has exchange from the red blood cells to the other cells that need it occur. Capillaries can also be thought of as the connectors between arteries and veins.

Venules – Smaller branches of veins.

Veins – the big ones. You should know already. Veins carry blood TO the heart.

Circulation – there are TWO types:

Systemic – all circulation to ALL tissues of the body (except for the lungs)

Pulmonary – circulation to the lungs. (Don’t ask… I dunno…)

Blood (isn’t it funny of Donahue says this word? Listen to him next time… and laugh… out loud! J )

A VISCOUS fluid composed of:

Red Blood Cells (RBC’s)

White Blood Cells (WBC’s)

Plasma

The FUNCTION of RBC’s:

They carry O₂ from the lungs to the tissues.

They carry CO₂ from the tissues to the lungs.

There are 5 BILLION RBC’s in just one cubic centimeter (cc) and you have 5 L of blood. Therefore, there are over 25,000,000,000,000 (25 trillion) red blood cells in the ENTIRE BODY!

Now remember that EACH RBC has 250,000,000 Hb molecules (HEMOGLOBIN molecules), and that EACH Hb molecule can carry 4 Oxygen (O) molecules…

The FUNCTION of WBC’s:

The major purpose of white blood cells is to defend against foreign enemies and infection.

Plasma (what fun!)

Plasma fluid contains 7% protein containing albumin, globulin, and fibrinogen (responsible for clotting the blood… For example, if Dr. Donahue sliced your head off and you didn’t have these proteins, well… "then you die!"

The Circulatory System – it’s a continuous circuit and a given amount of blood is pumped by the heart. This amount must flow through each subdivision of the circulation.

Lungs – area where O₂ is taken in. Blood pumped to the lungs via the pulmonary circulation system engages in gas exchanges, taking in O₂ while letting go of CO₂ (exhaling).

Pulmonary Vein – Vein going TO the heart FROM the lungs with newly oxygenated blood.

Left Atrium – area of the heart where newly oxygenated blood from the lungs comes in.

Left Ventricle – very muscular part of the heart. Another chamber that sits next to the left atrium, separated by the Atrioventricular valve (A-V valve for short… for obvious reasons…) Because this is the part of the heart that is pumping the blood to all parts of the body, it’s gotta be really strong.

Arteries – DUHHH… carry blood AWAY from the heart

Capillaries – gas / stuff exchange occurs between them and the cells. See above if you didn’t already get the idea.

Veins – DOUBLE DUHHH… carry blood TO the heart (Remember: For every artery, there is a complementary vein)

Right atrium – area of the heart that the coronary vein empties into.

Right ventricle – part of the heart that pumps the blood through the pulmonary artery to the lungs. Isn’t really muscular since it’s only going a short way. Separated from the right atrium by another atrioventricular valve.

Atrioventricular (AV Valve) – the major purpose of ANY valve of the heart is to only allow blood flow in ONE direction. Otherwise, deoxygenated blood goes in the wrong direction, and then "you die". The AV valve is located between the atrium and the ventricle. (Hence the name ATRIOVENTRICULAR VALVE!!!)

Aortic Valve (or Semilunar Valve) – valve inside the main arteries (pulmonary and coronary) that keep blood going in one direction.

REMEMBER: The heart contracts from the bottom up!

The "normal" blood pressure is 120 over 80

The SYSTOLIC blood pressure is when the blood pressure INSIDE YOUR ARM (in mm Hg) when the heart is contracting.

The DIASTOLIC blood pressure is when the heart is NO LONGER CONTRACTING (relaxed).

When the blood is released through the semilunar valve, the blood pressure INSIDE the heart rises from 0 to 120 (which is about what it is inside your arm… there is only a slight difference) This is on the left side of the heart.

On the RIGHT side, there isn’t much change in blood pressure at all… since all you need to do is get the blood to the lungs and back.

BE SURE TO STUDY THE GRAPH OUT OF THE NOTES!!!! (When blood pressures rise and fall.)

Blood pressure is directly related to actions of the heart and the EKG. Here’s a sequence of actions that causes blood pressure to rise:

The A.V. Valve closes (stopping blood to the ventricle), making the ventricle contract (drawing blood in), and then the aortic valve opens (blood goes out of the heart from the ventricles through the arteries). Also, the atrium relaxes. This creates the QRS complex in the EKG. During this time, pressure in the left ventricle starts to builds up. This is the first heart sound "lub". This is the SYSTOLE.

Then, the A.V. Valve opens (letting blood from the atrium into the ventricle), and the aortic valve closes (blood stops coming out of the heart). The left ventricle pressure drops. Compared to the EKG, it comes between the T and P waves. This part, which is also the second heart sound, "dub", is called the DIASTOLE.

An EKG is an ELECTROCARDIOGRAM… it looks at the electrical impulses that pass over your heart.

The Sino-Atrial node, located in the right atrium of the heart, sends an electrical impulse that starts the heart beating.

The Atrioventricular node receives that electrical impulse and sends an impulse down towards the bottom of the heart. This starts the heart to contract from the bottom up.

When using and EKG, the EKG leads are positioned at the four corners of the heart in order to sufficiently detect the electrical impulses. These impulses are graphed over the x axis of time, for a "picture" of the heart beats.

The human heart is myogenic… which means that if I ripped out your heart and put it on the table, it would beat by itself on the table… but of course, "then you would die…" This has something to do with SODIUM, but I’m not exactly sure what…

There are a number of "bad" EKGs that you should be able to spot:

Tachycardia (heart rate of over 100 beats per minute) – may mean a couple of things. Your cells could be needing a lot more O₂ and other "good stuff", so the heart is pumping faster (like if you’re running or exercising). OR, if this keeps up for a long time, it could mean that you need to pump a whole lot more for such a small amount of blood to get through. Your heart is getting tired and you could have a heart attack!!! (Or maybe you just saw your "significant other" or something… J (The EKG of this is just a bunch of fast heart beats)

Ventricular Fibrillation – a.k.a. uncoordinated contraction of the ventricles. Everything looks OK at first, but then you see that the ventricles are contracting by themselves, and not in order. That means that there’s DEFINITELY something wrong. (Go get the doctor… because "you’re gonna die…") (The EKG of this look just like a bunch of squiggly lines… it’s all messed up… you can tell)

Heart block – (failure of stimulation to ventricles following atrial contraction). Really noticeable on the EKG because a QRS complex is skipped.

On an EKG, the most common positioning of the EKG leads are at the four corners of the heart, but there a bunch of different arrangements too that can help you see other things like irregularities in heart beats (heart murmur), decreased blood supply, and more. One common example is putting the leads straight across the chest. That will give you an ABCD wave. (Don’t ask… something he said in class…)

REMEMBER:

P wave – the atrium contracts

QRS complex – the ventricle contracts and the atrium relaxes.

T wave – the ventricle relaxes.

HIGH BLOOD PRESSURE: ("remember this stuff because half of you out there are going to die from it…"

The measure of systolic and diastolic pressure in the arteries is what is referred to as BLOOD PRESSURE.

High blood pressure is commonly known as hypertension. It is an abnormally elevated blood pressure frequently associated with structural and functional abnormalities of many organs, particularly blood vessels, the heart, the brain, and the kidney. (i.e. you will DIE!!!)

Normal B.P.’s vary, but it is usually 120/80 (120 mm Hg when the heart is contracting, 80mm when the hear is relaxing)

The causes of high blood pressure include:

the "garden hose" effect – "Constriction"

Diastolic B.P. is over 90 (don’t ask… I dunno…)

Atherosclerotic: Plaques can from ANYWHERE where there is a "wettable" solution (place where extra cholesterol floating around in the blood stream can stick to and start to clog. - area of HIGH hydrophobicity) Like I said, this can occur ANYWHERE... if it’s at the carotid or jugular, there’s loss of blood to the brain and you die from a stroke. If there’s blockage at the kidney, you get renal failure. If there’s blockage in the HEART (coronary vein, etc.), then you get an all out HEART ATTACK.

SHOCK

Shock is defined as the inadequate propulsion of blood into the aorta, and therefore a high amount of blood is not profusing to capillaries. (i.e. no blood to certain parts of the body)

Smooth muscle fibers in metaaterioles and precapillary sphincters are controlled by local humoral environment (i.e. O₂, CO₂, H⁺ ions, electrolytes (Na, K, Ca) and Adenosine.

Stuff goes along to the precapillary sphincter, and let by 1 RBC at a time. THAT is a "true" capillary.

Twice as much "stuff" goes back from the capillaries to the heart. (This is because of the "lymphatic system"... it’s like blood, but it has lymph instead of RBCs. The lymph system is parallel to the venal system.

Cardiogenic Shock - long standing overwork of the heart muscle or actual loss of muscle tissue (in the hear.... OUCH!)

1. Myocardial disease - caused by a virus: Like CHICKEN POX - unlike the liver and muscles, the nervous system and the heart does NOT regenerate. So it gets DEADLY if the heart is directly attacked, because it will KILL YOU TILL YOU DIE!!!

2. Electrical failure - If the SA node or the AV node doesn’t work (like if it gets misdirected in the wrong directions), then you need something else to "keep the beat", so to speak. Then, you get a PACEMAKER... but it doesn’t have to be in your heart. You can put a strong one in your arm, and it’ll make the "Beats" for ya.

3. Coronary Artery Blockage - ‘nuff said... if you get atherosclerotic plaques here, you automatically get a heart attack (do not pass go, do not collect $200)

4. Valvular Heart Disease - this happens especially if you’re over weight (like some person / people I know)... you work too hard to do simple tasks and it makes your valves fail. Remember - if your valves don’t keep the same blood in the right direction, "... then you die!!!"

5. High Blood Pressure - ‘nuff said...

What are the effects of Heart Failure???

1. Fatigue on little exertion (you work a little, and then you die...)

2. Stiffness of the lungs - shortness of breath.

Cholesterol is in this little bubble type thing, with a protein on the surface of the bubble (hence called a SURFACE PROTEIN) This entire thing is called the LDL (low density lipoprotein) molecule. You get this from the stuff that you eat on a daily basis. These are really bad... VLDL’s (very low density lipoproteins) are even WORSE!!!! DON’T EAT ‘em!!!

HDL’s are GOOD!!! (They can "sweep out" these LDL’s and VLDL’s)

On the cell’s plasma membrane (made of a phospholipid bilayer), there are LDL RECEPTOR PROTEINS (these look like wrenches stuck in the thing... :) )

If there aren’t enough of these, it may be genetically associated, and you might not be able to handle that much of that cholesterol. That means WATCH YOUR DIET.

If there aren’t enough to take in the cholesterol (or you have WAY too much cholesterol), then it stays in the blood and could help aid the build up of an atherosclerotic plaque.

RABBITS have a lot of these things! (THIS WILL PROBABLY BE ON THE TEST!!!) You can’t kill a rabbit by giving it a bunch of fat to eat...

The LDL molecule binds to the LDL receptor protein and is drawn inside the cell so it can be used for "stuff..."

This was discovered by a pair of scientists named Goldstein and Brown, professors at UTHSC-D (University of Texas Heath Science Center at Dallas)

50% of the phospholipid bilayer is made of cholesterol. It is VERY important in movement of the cell and the flexibility of the cell (accounts for the "fluid mosaic model" of the cell)

1. If there is a low # of LDL receptors - this is probably genetic and is pre-determined

2. So, there is a lower amount of cholesterol in cells...

3. Cholesterol synthesis goes UP (HNG-CoA-Reductase... something to do with this...)

4. There are more LDL’s in the blood as a result.. ("THEN YOU DIE!!!!")

5. KNOW GOLDSTEIN AND BROWN!!!! I BET YOU $50 million pesos that it’ll be on the test!

The LDL particle / molecule is made up of:

an apo-b protein

a phospholipid bilayer

cholesterol esters on the inside

* These LDL particles bind to LDL receptors that are only in clathrin coated pits. This is a big characteristic that restricts the areas where LDL’s can bind for endocytosis into the cell. KNOW HOW THIS WORKS!!!

After being taken out of the "coated vesicle", the cholesterol is used for stuff, and the receptors are RECYCLED out to the plasma membrane to be reused again.

This is where the idea of down regulation comes into play. Question: Is it better to let kids eat all of their candy on one night? Or over the course of a month?

The ANSWER is ALL ON ONE NIGHT! Surprising? Not really. The same idea of clathrin coated pits is the same for glucose. Glucose needs to be endocytosed into the cell because it’s too big to pass through the plasma membrane on its own. There are only so many of these receptor areas where glucose can come in. If they’re all being used at once because there is so much glucose, then no more glucose can come into the cell, and the extra stuff is simply excreted out. So, eat as much candy as you want… but no more! J

The Lymphatic System

This system parallels the VEINS and NOT the arteries.

The purpose of the lymphatic system is to take weird waste and process WBC stuff…

Lymph – It’s similar to blood, but contains NO RBC.

The lymph system goes back to veins at the LEFT THORACIC VEIN

Lymph is processed at dropped off at the LYMPH NODES.

Lymph glands – tonsils of thymus?

There are tons of diseases associated with the lymphatic system:

One that he talked about is called elephantiasis: it occurs when a microfalarial worm clogs up the circulating lymph and causes BIG swelling in your lymph nodes…

The major lymph nodes are located in the tonsils, groin, under the armpits, and in the neck.