Biology 20-1 Excretory System

When people have kidney failure they have to go through dialysis. There are two types, explain them

- Hemodialysis: Blood is pumped from the artery to a dialysis machine. In the dialyzer waste products filter from the blood through an artificial membrane into the dialysate. - Peritoneal Dialysis: (Peritoneum is the space between your organs) They take the dialysis fluid and hook it to the surgically implanted valve and this fluid is floating around your organs which are all semipermeable.

Give two reasons why K+ is more concentrated in the urine than the filtrate.

1. Some of the K+ ions have been secreted into the fluid in the tubule. 2. Water has been reabsorbed increasing the concentration of the K+

What is diabetes insipidus?

Caused by insufficient ADH production, dilute urine, may be treated with synthetic ADH.

Explain diabetes mellitus type one

Caused by not enough secretion of insulin from pancreas because your immune system attacks cells of the pancreas

What does the glamorous and the Bowman's capsule do?

Filtration of water and dissolved solutes occurs as blood is forced through the walls of the glomerus into Bowman's capsule by fluid pressure in the capillaries.

Three steps of urine formation?

Filtration, reabsorption, secretion

The removal of an amino group from a protein (happens in the liver)

deamination - When you eat a protein (like a burger) your digestive system breaks the proteins into amino acids and rearranges them to form proteins the body can use. When our body breaks down an amino acid ammonia is produced which is toxic, so your body turns it into urea. The carbon residue is turned into glucose which is turned into glycogen which is stored in the liver and the muscles.

glucose in the urine, extreme thirst, and fatigue might indicate this disease

diabetes mellitus

Blood plasma moving into the nephron

filtration

This energy compound is immediately reabsorbed in the proximal tubule

glucose

What other useful substances, in addition to Na+, Cl-, and water, are reabsorbed in the proximal tubule?

glucose and amino acids, water reabsorption, bicarbonate ions, potassium.

These calcium deposits form in the kidneys and will need to be passed

kidney stones

This 85% successful procedure might be in trouble if the immune system doesn't cooperate

kidney transplant

Urine with blood proteins might be the result of this disease

nephritis

This blood cleaning technique makes use of the linings of the internal organs

peritoneal dialysis

What occurs in the proximal tube?

selective reabsorption of nutrients from filtrate back into blood occurs by active and passive transport. Within proximal tube pH is controlled by secretion of hydrogen ions and reabsorption of bicarbonate ions.

The tubes connect the distal tube and lead to the renal pelvis

the collecting ducts

Its all about water reabsorption here

the descending loop of henle

Ions are solely transported by this active transport in this section of the nephron

the distal tube

This part of the nephron only works under high pressure

the glomerus

These organs are the site of excretion

the kidneys

Form the mid section of the kidney

the medulla

The functional unit of the kidney

the nephron

These capillaries wrap themselves around the tubule of the nephron

the peritubular capillaries

The hollow area of the kidney that joins the ureters

the renal pelvis

Tube responsible for transport of urine out of the body

the urethra

When the maximum amount of a substance has moved across the nephron

threshold level

The most commonly concentrated solute found in the collecting ducts

urea

This ion is actively transported out of the nephron. Cl- and water soon passively follow.

Na+

Where are kidneys placed in a kidney transplant?

A kidney transplant involves placing a new kidney and ureter in the lower abdomen where they are surgically attached to blood vessels and the bladder. The old kidneys are rarely removed.

This hormone adjust water homeostasis by making the distal tubule more permeable to water

ADH

Hormonal control of water homeostasis with ADH

ADH - Osmoreceptors in the hypothalamus detect osmotic pressure. When you're dehydrated the concentration of solutes in the blood increases leading to an increase in osmotic pressure. When water needs to be conserved the pituitary gland releases antidiuretic hormone (ADH) into the bloodstream. ADH increases the permeability of the distal tubule and collecting duct which increases water reabsorption.

Why does coffee make you have to pee so badly after?

ADH increases the permeability of the distal tubule and collecting duct which increases water reabsorption. When you have something like coffee, it blocks the ADH so water can't exit.

List three examples of substances that are actively secreted into the filtrate. How is blood pH maintained by tubular secretion?

Ammonia, excess H+ ions, and minerals such as K+ ions.

Why are useful molecules like glucose and other nutrients found in the filtrate along with urea and other wastes?

Because they move from an area of high concentration to low concentration. They are later reabsorbed.

Sometimes bacterial infection causes nephritis—an inflammation of membranes in the glomerulus and capsule. Large pores are created through which blood cells enter the nephron. What symptom would indicate this problem?

Blood in the urine

Why are blood cells and proteins not found in the filtrate?

Blood proteins are too big to move through the walls of the glomerus .

Neither glucose of blood proteins are present in the urine, but for different reasons. Explain

Glucose is completely reabsorbed where proteins are to large to fit through the glomerus.

What is gout?

Gout is when you have too much uric acid you get crystals in your tissues/joints.

This ion is secreted in order to control blood pH homeostasis

H+

Which ions account for the low pH of urine? Why is the elimination of this ion important?

H+ ions. They are transported by being actively secreted into the proximal and the distal tubules. If too many H+ ions were allowed to stay in the blood the pH level would drop. The blood would be delivered to cells and the pH level of the cells would change, and the enzymes couldn't function properly resulting in eventual death.

Explain how reabsorption of ions and water occurs from the distal tubule.

Ions are actively transported out of this section as needed by the body. The distal tubule is not permeable to water unless the hormone ADH is present. If the hormone is present the water will leave the tubule through osmosis.

Explain the process of reabsorption from the descending loop

It is permeable to water resulting in loss of water by the filtrate by osmosis. Salt becomes concentrated in the filtrate as descending limb penetrates the inner medulla of the kidney.

One of the effects of drug overdose is decrease in blood pressure. How might this effect kidney function?

Less materials are moving into the kidney because they move from areas of high concentration to low concentration, so less wastes are excreted.

What is secretion?

Moving materials from one place to another place in the body. Ex: Your lungs secrete carbon dioxide, your liver secrets bile.

Although urea undergoes less reabsorption that glucose its concentration in the urine increased about 60-fold. Account for the increase.

Not as much urea is reabsorbed than glucose. So much water is reabsorbed that by the time urine is in its final composition the urea is very concentrated compared to the water that is still there.

Explain diabetes mellitus type two

Not enough insulin produced or insulin doesn't work anymore

What are some differences between aldosterone and ADH?

One is triggered by low blood pressure, and one is triggered by osmotic pressure. One saves water by causing more salt to be reabsorbed in the blood causing the water to follow, and one increases the permeability of the distal tube and collecting duct which increases water reabsorption. One comes from the pituitary gland and one comes from kidney.

Hormonal control of water homeostasis with aldosterone

Receptors in the kidney detect low blood pressure due to dehydration or fluid loss. Increased aldosterone from the adrenal glands cause more NaCl to be reabsorbed. Water follows the salt and is reabsorbed into the blood increasing blood volume and blood pressure.

What is excretion?

Stuff moving out of your body. Ex: urine from the bladder, tears from tear ducts, vomit from the stomach, etc.

What do afferent arterioles do?

Supply the nephrons with blood.

In terms of energy costs to the cells in the proximal tubule, the reabsorption of salt (Na+ and Cl-) and water has been called a deal where we get "3 for the price of 1." Explain.

The only energy cost is the energy needed to actively transport Na+ ions across the proximal tubule membrane. The Cl- ions will passively follow due to attraction to the Na+ ions and the water will osmose due to osmotic pressure increasing in the interestial fluid.

Explain the process of reabsorption from the ascending loop

The sending loop is permeable to salt and not water. At the bottom of the loop salt is passively transported, near the top of the loop salt is actively transported . The salt enters the interestial fluid making the fluid in the medulla of the kidney very salty.

What are treatments for kidney stones?

Treatments for kidney stones include: Medications (causing the urethra to dilate) and ultrasound to break up stones

What are some things that need to be secede from the blood?

Urea, alcohol, pesticides, etc.

What is uric acid?

When there is too much nucleic acid it is broken down in the liver and turned into uric acid. Uric acid enters urine in order to be eliminated from the body.

What is the glomerus?

a high pressure capillary bed that is the site of filtration.

What are the pertibular capillaries?

a member of the network of small blood vessels that surround the tubule of the nephron.

What are the efferent arterioles?

a small branch of the renal artery that carries the blood from the glomerus to the pertibular capillaries.