To The Nephron and Back: A Water Molecule Chronicle

"This is sure an strange place", Osmo thought to himself as he looked around and saw a bunch of unfamilar beings. "Why are those guys over there so red? And for that matter why are those guys so clear? and hey! those gals look just like me! Good to know im not the only one capable of Osmosis around here." Surging through this tunnel he saw a sign:
Welcome to the Renal Artery!
"Well that doesn't sound too bad" he thought. Just then, the current slowed a bit and he was diverted into a mass of smaller tunnels, twisting and turning, as he passed another sign:
THE GLOMERULUS, Where capilaries have a ball!
"Atleast things are slowing down a bit," he again thought to himself.
Just then he was sucked through a wall into a sort of tube.
"Woah! That was weird! Where ever I'm headed it seems like there is some organization to this chaos, 'cause none of those red or clear guys followed into this tunnel."
As Osmo got his bearings he saw yet another sign:
Bowman's Capsule, We've got the Glomerulus surrounded!
Just then, he some of the other water molecules being sucked out of the tubule, along with a bunch of the other unfamilairs that had followed him. Again, he passed another sign:
Proximal Tubule, It's all down hill from here!
"Ahhhhh!" Osmo screamed as the current acelerated and the tubule narrowed. Many more of his kind were sucked out of the tubule into the unknown. For some reason, he and a few others were left behind. As he went down the walls seem to get darker, as if whatever was outside was slowely becoming more concentrated.
Up ahead was a hairpin turn, and yet another sign:
Loop of Henle, turning molecules around since 1991
As the turn completed Osmo looked around at the changing walls "Woah, these walls look alot harder to go through, i don't think even the skinniest H20 molecule could squeeze through that." as the tunnel leveled out he passed a sign again:
Distal Tubule, far from a Bowman
"I wonder if they mean that Bowman's Capsule?" he thought as some of the water molecules came back into the tunnel. "I guess they didn't need us." Osmo heard one of them state. "Or mabye they couldn't handle all of us," he heard another suggest. "I've been to a place like this before and there weren't nearly as many of those ADH guys here," yet another suggested. They all passed another sign:
Collecting Duct, Merging waste is our business
"Surely this can't go on much longer," Osmo though to himself, "This has being going on forever."
Just as he thought this the collecting duct merged into other tunnels that seemed alot like it, brining more fluid into a bigger tube which had another sign:
Ureter, Last stop before the B
"What on earth is 'B'?" Osmo thought,"That sign did look like it had been disovled somehow"
Suddenly the tunnel let out into a huge chamber with what seemed like an ocean of clear liquid.
"Finally, it stops." Thought the tired Osmo. And for awhile he was right but as more and more liquid came from the tunnel, the giant chamber started to fill up. "What will happen when it fills all the w-AHHHHH!" Osmo was sucked down into a whirlpool of swirling liquid and was forced down yet another tunnel which had another sign, he didnt get a good look at it but from what he could tell it read
Urethra, See Ya!
He swirled and surged on past the sign and out into a stream where he was blinded by the bright light. As his vision cleared he was again in a familair place, dominated by his kind and bacteria.
"Well, what an adventure! I can't wait to tell the guys about this!"

Digital Citizenship

You are now required to use attributions for all of your posts. What does this mean? It has a lot to do with digital citizenship and protecting intellectual property. Underneath the information that you post, please post where the information came from. You may simply cite you work. Here is an example:

Attributions:

DNA image:

http://www.3dscience.com/img/Products/3D_Models/Biology/DNA/DNA_w_Phosphate_structure/Supporting_images/3d_model_DNA_w_phosphate_1.jpg

*Just for an overview, remember that a solute is what is dissolved, while a solvent the solute is dissolved in. The "universal solvent" is water.

*Also remember the emperical formulas for different molecules in digestion.

Carb - CH2O

Fat - CHO

Protein - CHNO

Nucleic Acid - CHNOP

As you know, homeostasis refers to an animal's ability to regulate its internal environment. Thermoregulation refers to how animals maintain their internal temperature, and osmeoregulation refers to how they regulate solute balance and water content.

The digestion and utilization of proteins creates the greatest need for osmeoregulation in the kidneys.

Thermoregulation takes place through the following processes:

1. Adjustment of rate of heat exchange between the animal and its environment - through insulating hair, feathers and fat - is accomplished through vasodilation (in increase in the diameter of blood vessels at the skin, which cools the blood) or vasoconstriction (the opposite of vasodilation).

2. Evaporation across the skin (through panting or sweating)

3. Behavioral responses (changes in location or posture) Eg. Shivering, or lizards moving off of a hot rock.

4. Alteration of the rate of metabolic heat production (only in endotherms)

Most metabolic wastes must be exreted from the body. One of the most important waste products is nitrogen-containing breakdown products proteins/nucleic acids.

Mammals have two kidneys, and each is supplied with blood by a renal artery and a renal vein. Urine leaves the kidneys through the uterers, which drain into the urinary bladder. Urine is expelled from the body through the urethra.

*Know your U's!

The kidney has two regions: the outer renal cortex and the inner renal medulla. These 2 regions are packed with nephrons, which are the functional units of the kidney.

Nephrons are made up of a single long tubule and the glomerulus, a ball of capillaries. At the end of the tubule is the Bowman's Capsule, a c-shaped capsule that surrounds the glomerulus.

The filtrate flows through the proximal tube, the descending loop of Henle, the loop of Henle, the ascending loop of Henle, and the distal tubule. The distal tubule empties into a collecting duct, which receives wastes from many nephrons.

In the human kidney, most of the nephrons are cortical nephrons that are in the renal cortex. The rest are juxtamedullary nephrons with long loops of Henle that extend into the renal medulla.

Capillaries called afferent arterioles are associated with nephrons, and as they leave the glomerulus, the capillaries converge into an efferent arteriole. This vessel subdivides again to form peritubular capillaries, which surround the proximal and distal tubules.

Questions:

1. What is the first stage inside the nephron and what is occuring?

a. Filtration - materials from the blood are moving from the glomerulus into the Bowman's capsule

b. Filtration - materials from the proximal tube are diffusing back into the blood stream and interstitial fluid

c. Reabsorption - materials from the blood are moving from the glomerulus into the Bowman's capsule

d. Reabsorption - materials from the proximal tube are diffusing back into the blood stream and intersitial fluid

2. Which of the following is NOT true?

a. During vasodilation, the blood vessels farest away from your skin are expanding and cooling your blood.

b. The liquid inside the Bowman's capsule is filtered blood

c. Juxtamedullary nephrons extend into the medullary, not just inside the renal cortex

d. The renal artery takes blood to the kidney

3. During vasoconstriction, what is happening?

a. The superficial blood vessels dilate, which cools the blood

b. The superficial blood vessels constrict, which cools the blood

c. The superficial blood vessels dilate, which heats the blood

d. The superficial blood vessels constrict, which heats the blood

Answers: a, a, c

Insulin/Glucagon and Calcitonin/PTH in your body

Glucagon Versus Insulin

If there’s a high level of glucose, insulin is secreted from the pancreas in order to decrease that level. Cells in your body then take up glucose, storing the molecules as glycogen, and you become tired. The pancreas then secretes glucagons so that the glycogen turns back into the glucose, used as energy for your body.

Things to remember:
1. Both glucagons and insulin are secreted from the pancreas.
2. The liver acts on glycogen
3. Beta cells (only in the pancreas) release insulin, which decreases glucose levels.
4. Alpha cells (only in the pancreas) raises glucose levels by secreting glucagons

This picture shows the effect of insulin/glucagon in the body.

Calcitonin versus PTH

Calcium is created from osteoclasts, which make it from your bone fragments. When there is too much calcium, calcitonin is released from the thyroid gland in order to block the osteoclasts, and therefore, prevent calcium production. If the calcium levels are too low, PTH comes from the parathyroid gland, goes to the osteoclasts and tells them to start up again. This causes calcium levels to rise.

Things to remember:
1. PTH and vitamin D work together to put calcium in your bones.
2. Vitamin D is sunlight, and you need to be exposed by it in order to absorb calcium.

This picture shows the effect of calcitonin/PTH in your body.

Questions:

1. From where are glucagon and insulin secreted?
a. Glucagon is secreted from the liver; insulin is secreted from the pancreas
b. Glucagon is secreted from the liver; insulin is secreted from the liver
c. Glucagon is secreted from the pancreas; insulin is secreted from the liver
d. Glucagon is secreted from the pancreas; insulin is secreted from the pancreas

2. Where is calcium produced?
a. Parathyroid gland
b. Thyroid gland
c. Osteoclasts
d. Osteoblasts

3. What do you need in order to absorb calcium?
a. Vitamin E
b. Vitamin D
c. PTH
d. Glucagon
Answers: d, c, b

Chapter 44 Preview: Regulating the Internal Environment

Animals are able to survive large fluctuation in thier external environment by maintaining a relatively constant internal environment. This regulatory ability is called homeostasis. Animals are able to maintain a favorable range in their internal temperature (thermoregulation), regulate solute and water balance (oamoregulation), and dispose of nitrogenous wastes (excretion).

Vocab:

nephron

endotherm

glomerulus

vasoconstriction

Bowman's capsule

counter current exchange

loop of Henle

heat shock proteins

collecting duct

uric acid

renal artery

antidiuretic hormone

renal vein

aldosterone

renal cortex

vasodilation

thermoregulation

ectotherm

conformers

osmoregulation

Roots:

vasa-a vessel juxta- near to glomer- a ball

eury- broad wide -dilat-expanded osmo- pushing

peri- around podo- foot reni- a kidney

steno- narrow

Chapter 40,41,42,43,45 Systems Review

Endocrine System

Circulatory System

Respiratory System

Immune System

Digestive System

Review Questions:

1.) The interstitial fluid of vertebrates.. (ch 40)

a: is the internal environment within cells

b:bathes cells and provides for the exchange of nutrients and waste

c:makes up the plasma of blood

d: surrounds unicellular and flat, thin animals

e: is less abundant in ectotherms than in endotherms

2.) Which is the best description of smooth muscle?(ch 40)

a: striated, branching cells; involuntary control

b: spindle-shaped cells; involuntary control

c: spindle-shaped cells connected by intercalated disks

d: striated cells containing overlapping filaments; involuntary control

e:spindle-shaped striated cells; voluntary control

3.) The acid pH of the stomach(ch41)

a: hydrolyzes proteins

b: is regulated by the release of gastrin

c: is neutralized by gastric juice

d: is produced by pepsin

e: triggers the release of enterogastrones

4.) Why does salivary amylase not hydrolyze starch in the duodenum?(ch41)

a: Starch is completely hydrolyzed into maltose in the oral cavity

b: Salivary amylase is produced by salivary glands and never leaves the oral cavity

c: The acid pH of the stomach denatures salivary amylase and pepsin begins hydrolyzing it

d: Pancreatic amylase is a more effective enzyme in the pH of the duodenum

e: Salivary amylase can hydrolyze glycogen but not starch

5.)Where is blood pressure the greatest?(ch42)

a: vena cava

b: pulmonary vein

c: right atrium

d: aorta

e: pulmonary capillaries

6.) In which location would velocity of blood flow be the slowest?(ch 42)

a: vena cava

b: pulmonary vein

c: right atrium

d: aorta

e: pulmonary capillaries

7.) Which of the following is incorectly paired with its effect?(ch43)

a: gastric juice- kills bacteria in the stomach

b:fever- stimulates phagocytosis and inhibits microbial growth

c: histamine- causes blood vessels to dilate

d: vaccination-creates passive immunity

e: lysozyme- attacks cell walls of bacteria

8.) How does the immune system recognize malignant tumor cells?(ch43)

a: They do not display class I MHC molecules

b: They display fragments of tumor antigen in their MHC molecules

c: They display cancerous viral fragments in their class II MHC molecules

d: They have abnormal amounts of polysaccharides

9)Which of the following hormones is not involved with increasing the blood glucose concentration?(ch45)

a: glucagon

b:epinephrine

c:glucocorticoids

d: ACTH

e:insulin

True or False?(ch45)

Calcitonin is a hormone that raises calcium levels in the blood

1) b2) b3)b4)c5)d6)e7)d8)b9)e10)false!

Great Interactive Website

Go to this link http://www2.edc.org/weblabs/WebLabDirectory1.html

Try the interactive evolution/natural selection demos. Bookmark this link so we can use it again for genetics.

Ch. 42 continued

Blood is a connective tissue made up of:

1. Red Blood Cells (RBC)

-transport oxygen through hemoglobin*

-transport water soluble lipids

2. White Blood Cells (WBC)

-part of the immune system

3. Platelets

-responsible for clotting and immune responses

-Fibrinogen: a protein that when it becomes active turns into Fibrin

*Hemoglobin

- a respiratory pigment found in most vertebrates

-4 subunits with embedded iron atom to bind O2

-can carry 4 oxygen molecules

-Bohr Shift: the lowering of pH in blood

- does not commonly carry CO2 (CO2 most commonly carried in bicarbonate ions)

Cardiac Cycle

Systole:

- the contraction phase

- blood pressure is greater in the arteries

Diastole:

-relaxation phase

Heart Rate- the rate of contraction per minute

Stroke Volume-amount of blood pumped by left ventricle

Sinoatrial node: (SA)

-Pacemaker of the heart

-upper wall of right atrium

Atrioventricular node: (AV)

- allows the atria to empty of all blood

-lower wall of right atrium

Lymphatic System:

-returns lost fluid and proteins to blood

-Lymph nodes: filter lymph, attack viruses, and bacteria

Gas Exchange (respiration)

- the uptake of Molecular O2 and discharge of CO2

Larynx (voice box)

- tube made of cartilage

-leads to trachea (windpipe)

-divides in two Bronchi; leading to the lungs

-Bronchi split off into Bronchioles; ending in Alveoli (clusters of air sacs, where gas exchange occurs)

Lungs

-relatively large exchange surfaces

- across the lining of the alveoli

Gas diffusion:

-depends on pressure, go from high pressure areas into lower pressure areas

Multiple Choice:

1. The diffusion of gas diffuse from...

a. the lungs

b. low to high

c. high to low

d. the larynx

2. Blood is made up of

a. red blood cells

b. plasma

c. gases

d. all of the above

3. The sinoatrial node is

a. in the lungs

b. sets the rate of contractions in cardiac muscles

c. tells the blood to flow to certain places and when

d. in the lower part of the right atrium

Answers:

1. c 2. d 3. b

Blog

Chapter 42 – October 7, 2009

Closed Circulatory System- when blood is contained within vessels and is pumped around body. Blood is separate from interstitial fluid.

- Humans have closed Circulatory system called Cardiovascular System containing a heart with Atria and Ventricles.

Types of blood vessels: arteries, veins, capillaries

- Arteries pump blood away from heart into smaller arteries

- Capillaries form capillary bed which turn into veins that bring blood back to the heart

Vein: Large diameter, thin wall, contains valve to prevent backflow

Artery: Small diameter, thick wall

Double Circulation in Mammals

1. Right ventricle pumps blood to lungs through Pulmonary Artery
2. Blood flows through capillary bed in the lungs and receives oxygen and release carbon-dioxide
3. Blood returns to Left Atrium of Heart via Pulmonary Vein
4. It flows through Left Ventricle
5. Then it leaves the Heart via Aorta, which sends the blood to arteries throughout the body
6. Blood enters capillary beds in neck, head, arms
7. Blood enters capillary beds in abdomen and legs – giving up oxygen and picking up carbon-dioxide from cell respiration
8. Capillaries continue into venules which progress to veins, carrying blood from neck, head, and arms travel back to Right Atrium via Anterior Vena Cava
9. Blood from legs and abdomen travel through Posterior Vena Cava to Right Atrium

1. Blood returning to the heart in a pulmonary vein will drain first into the

1. vena cava
2. left atrium
3. right atrium
4. left ventricle
5. right ventricle

2. All of the following are blood vessels except:

a. veins

b. arteries

c. capillaries

d. venuoles

e. lymphatics

3. Which of the following is true of the mammalian Circulatory System

a. All arteries carry oxygenated blood to the body.

b. All veins carry deoxygenated blood

c. Right ventricle pumps blood to lungs through the Pulmonary Artery

d. Left atrium pumps blood to the body through the Aorta

Answer 1 b, 2e, 3c

Chapter 41 & Chapter 42

Today in class we discussed the breakdown of molecules through the digestive system and how the breakdown of these molecules (Carbohydrates, Proteins, Nucleic Acids, and Lipids) all end in the small intestine.

1) In small intestine pancreatic amylase breaks down starch, glycogen, and small polysaccharides into di saccharides. Breakdown of di saccharides occur at the wall of the intestinal epithelium, and then mono saccharides are quickly absorbed into blood.

2)Proteins- Pepsin, Pepsinogen prior to release in stomach,begins breakdown of proteins in stomach, Typsin breaks polypeptides into smaller into smaller chains. Then other enzymes (aminopetidase) break polypeptides into amino acids.

3)Nucleic Acids- Broken down by nucleases into nucleotides, sugars, nitrogenous bases, sugars, and phosphate groups.

4) Fats- Digestion of fats start in the small intestine (SI). Bile salts coat fat droplets to keep them from coalescing (in emulsification) and lipase hydrolyzes them. Most fat enters the lymphatic system first.

Coalescing-to come together

Stage 3 of digestion- Absorption

1)Absorption occurs in SI in epithelial lining with folds called villi which have micro villi, both increase surface area for absorption.

- Each villi has a set of tiny blood vessels called capillaries and a lymph vessel called lacteal

-- Lacteal absorbs fatty acids

- Mono saccrides such as glucose enters blood stream via passive diffusion (requiring little energy) while amino acids and dipeptides enter via active transport (requiring energy).

2) All caoillaries and veins from villi all join at the hepatic portal vessel, which brings the blood to the liver. The liver metabolizes the organic molecules in various ways.

- Liver has smooth ER ( endoplasmic reticulum) organelles that detox the blood.

Hormones

- An important hormone in digestion is gastrin, which stimulates the secretion of gastric juice.

Stage 4- Elimination

Large intestine, colon, is connected to small intestine by a sphincter. The point of connection is the site of the cecum, a small pouch with an extension called the appendix.

- Main function of the large intestine is to compact waste and recover water from it.

- End of colon is rectum where feces are stored until they are eliminated.

Chapter 42- Circulation and Gas Exchange

- Both open and closed circulatory systems have blood, vessels, and a heart structure.

- Open circulatory system- blood bathes the organs directly.

- Blood+Lymph= hemolymph; the heart pumps hemolymph into cavities called sinuses

(Definitions for lymph and hemolymph can be found in ch. 42 voc.)

Questions

1) What hormone stimulates the secretion of gastric juice?

A) lymph

B) gastrin

C) pepsin

D) aminopetidase

2) What substance in stomach aids in breakdown of proteins

A) pepsin

B) bile

C) amylase

D) lipase

3) What structure in small intestine is vital for absoption?

A) lipids

B) sphincter

C) bile

D) villi

Answers: B,A,D

Chapter 41 Notes

• More complex animals have complete digestive tracts (alimentary canals), which are one way digestive tubes that begin with the mouth at one end of the terminate in the anus at the other.




• Complete vs. gastrovascular -complete has an advantage of having specialized regions.




• 4 Types of Organs: Mouth, esophagus, stomach, small intestine

Step By Step of the Human Digestive System

• When food is in the mouth, or oral cavity, a nervous reflexoccurs which causes saliva to be secreted into the mouth. Saliva lubricates the food and contains the enzyeme Salivary Amylase, which hydrolyzes starch and glycogen (polysaccrides-complex carbohydrates) into smaller polysaccridesand the disaccharide maltose. This is typically the 1st type of macromolecule to be enzematically attacked.




• During chewing, food is shaped into a ball called a bolus. After being swallowed, the bolus enters the pharynx - a junction thta opens to the esophagus and the trachea. During swallowing, the epiglottis (a flap made of cartiledge) moves to cover the trachea. This will divert the foodto go down the esophagus.




• The esophagus moves food from the pharynx down to the stomach though peristalsis-rhymic waves if contraction by smooth muscle in the walls of the esophagus. (also occurs in the alimentary canal)




• The stomach is in the upper abdominal cavity, and it's functions include storing food and secreting gastric juice.




• Gastric Juice contains hydrocholic acid, which is very acidic (pH of about 2). Gastric juice breaks down the extracellular matrix of meat and plant materials, and it also kills most of the bacteria ingested with the food.




• Gastrin is a hormone produced by the epitheial lining of the stomach.




• Chyme is a soupy mixture of acids and food particles in your stomach.




• Pepsin is an enzyme in gastic juice that begins to hydrolyze proteins into smaller polypeptides. Pepsin secreted in an inactive form called pepsinogen, which is activated by the hydroclhloric acid in the stomach.




• The result of digestion in the stomach is a substance called acid chyme. The acid chyme is shunted from the end of the stomach into the beginning of the small intestine via the pyloric sphincler.




• Rugae is the inner linings of the stomach ---> more surface area




• The small intestine (final breakdown) is the longest, 6m, section of the alimentary canal. The beginning of the small intestine is the site of most of the hydrolosis of macromolecules, and the rest of the small intestine is responsible for the absorbtion of nutrients into the blood.




• The 1st section of the small intestine is known as the duodenum. In the duodenum, the acid chyme mixes with sections from the pancreas (bicarbonate, which acts as a buffer against acid chyme), the liver (bile, which contains bile salts-detergents that aid in digestions and help stabilize fat emulsions), the gall bladder, and the intestinal itself.




• REMEMBER: Bile is produced in the liver and stored in the gall bladder. (That is why the gall bladder is green)




• The gal bladder has no digestive secretions.

QUESTIONS:

1. Which of the answers is not considered one of the main organs?

A. Pepsin

B. Mouth

C. Esophagus

D. Small Intestine

2. Where is bile produced?

A. Gallbladder

B. Liver

C. Stomach

D. Pharynx

3.What is an example of a complex carbohydrate?

A. Gastric juice

B. Polypeptides

C. Salivary Amylase

D. Glycogen

ANSWERS: 1. A, 2. B, 3. D

Pictures:

http://www.gallstoneinformation.com/wp-content/uploads/2009/03/ency4beta_getimageaspx.jpg

http://3.bp.blogspot.com/_PC3aIMjVWm8/SRQJWXHfmII/AAAAAAAAAmg/EZAsuaAqIEo/s400/Human-Digestive-System-Picture.jpg