Excretory System

Question 1

what is the purpose of the skin in the excretory system?

Answer 1

the sweat glands secrete perspiration, which is water, salt, and urea.

**the main purpose of sweating is temperature regulation, not to excrete wastes.

Question 2

what is the purpose of the liver in the excretory system?

Answer 2

excretes bile that is created when hemoglobin is broken down.

The MAIN PURPOSE of the liver in this system is to filter out the urea and uric acid from the blood.

Question 3

define DEAMINATION

Answer 3

removal of an amino acid group from an organic compound

ex. amino acids, nucleic acids

Question 4

how is urea formed?

Answer 4

ammonia, which is extremely toxic, is produced from deamination and is combined to form urea.

Question 5

how is uric acid formed?

Answer 5

uric acid is formed when the liver breaks down nucleic acids.

Question 6

What is the purpose of the lungs in the excretory system?

Answer 6

their job is to remove carbon dioxide(CO2) from the body.

Question 7

what is the urinary system?

Answer 7

the main system that excretes waste from our body.

Question 8

what does the word renal refer to?

Answer 8

the KIDNEYS

Question 9

what is the function of the kidneys?

Answer 9

the kidneys produce urine, which contains nitrous wastes like urea and uric acid.

Question 10

what are the 3 regions of the kidney?

Answer 10

Renal CORTEX- outer layer made of connective tissue
Renal MEDULLA- middle layer
Renal PELVIS- central collecting space where urine drains into.

Question 11

How do the kidneys work?

Answer 11

The kidneys, each the size of a fist located on either side of the spine below the diaphragm. They are fed by the renal artery that branches off the aorta, and they have a renal vein that leaves the kidneys and enters the inferior vena cava. Each kidney is made up of millions of nephrons where the urine is produced.

Question 12

define URETERS

Answer 12

the muscular tubes that carry urine from the kidneys to the bladder.

Question 13

how does urine move through the ureters?

Answer 13

through peristalsis

Question 14

define BLADDER

Answer 14

a hollow muscular organ that expands as urine enters

Question 15

define URETHRA

Answer 15

carries urine from the bladder to the external opening. Longer in males than females

Question 16

What are all the parts of the excretory system?

Answer 16

Renal artery, renal vein, kidneys, aorta, inferior vena cava, ureters, bladder, urethra

Question 17

define NEPHRON and explain how they work

Answer 17

the functional unit of the kidney. Each nephron is fed by a small afferent arteriole that branches off the renal artery. These arterioles then branch into a capillary bed, which is called the glomerulus. The glomerulus is surrounded by a funnel-like part of the nephron and this is called the bomans capsule. The capsule then tapers into a small thin tubule called the proximal tubule. Urine is carried from the proximal tubule into the Loop of Henle, then through the distal tubule, and then into the collecting ducts which collect the urine from many nephrons and drain into the ureters.

Question 18

AFFERENT vs EFFERENT

Answer 18

afferent- going in (before glomerulus)
efferent- going out (after glomerulus)

Question 19

What are the 3 parts of urine formation?

Answer 19

FILTRATION- glomerulus/bowman’s capsule
REABSORBTION- proximal tubule/loop of Henle
SECRETION- distal tubule

Question 20

How does filtration work in urine formation?

Answer 20

The glomerulus acts like a high-pressure filter. Water and dissolved solutes pass through, but things like proteins, blood cells, and platelets are too big to pass through so they stay in the blood.

Question 21

How does reabsorption work during urine formation?

Answer 21

Reabsorption occurs through both active and passive transport. Sodium ions are actively transported out of the cell, and since they are negatively charged all the positively charged ions transport out of the cell as well. Water follows this now because of osmotic force, the concentration is now higher on the outside of the tubules than inside the tubules. As the water leaves, the urine then becomes more concentrated and all that’s left is the waste that we call urine.

Question 22

how does the loop of Henle and the proximal tubule get its energy to actively transport substances?

Answer 22

there are many mitochondria in the nephron to provide this energy.

Question 23

how does secretion work in the urine formation process?

Answer 23

secretion is the movement of a substance from the blood into the nephron. Ammonia, excess hydrogen ions, and potassium ions all get moved into the blood due to active transport.

Question 24

DIURETIC

Answer 24

something that increases your urine output.

ex. caffeine