Week 11 notes

Question 1

What are the 3 main functions of excretory systems?

Answer 1

1. maintaining solute ion concentration
2. maintaining water balance
3. removal of toxic wastes.

Question 2

What are the 3 main excretory products in plants?

Answer 2

1.oxygen
2. water
3. ammonia.

Question 3

What are the 3 main excretory wastes in animals?

Answer 3

1. carbon dioxide
2. nitrogenous wastes
3. water

Question 4

What is osmosis?

Answer 4

Osmosis is:
1. The movement of water through a
2. selectively permeable membrane
3. from LOW solute concentration to HIGH solute concentration
4. and does not require energy.

Question 5

What is osmotic pressure?

Answer 5

The tendency of water to move by osmosis into a solution,

• The greater the difference in concentrations, the greater the osmotic pressure.

Question 6

What is an isotonic solution?

Answer 6

An isotonic solution contains the same concentration of solute outside of the cell as in cytoplasm of the cell.

Question 7

What is a HYPOtonic solution?

Answer 7

A HYPOtonic solution contains a lower concentration of solute outside of the cell compared to the cytoplasm of the cell.

Question 8

What is a HYPERtonic solution?

Answer 8

A HYPERtonic solution contains a higher concentration of solute outside of the cell compared to the cytoplasm of the cell.

Question 9

What is osmoregulation?

Answer 9

Osmoregulation is the process of maintaining an appropriate balance of:
1. water
2. salts
3. ions
in the body fluids.

Question 10

What is excretion?

Answer 10

The removal of waste substances from the body and may involve the removal of water and salts.

Question 11

What organs are involved with osmoregulation?

Answer 11

Excretory organs are often involved with osmoregulation

Question 12

What is homeostatic balance maintained by?

Answer 12

Homeostatic balance is maintained by osmoregulation.

Question 13

What are the splits of water loss in terrestrial animals?

Answer 13

1. the urinary system (50%)
2. perspiration (30%)
3. respiratory system (15%)
4. digestive system (5%).

Question 14

How do mammals replace their water?

Answer 14

Water replacement in mammals may occur through food and drinks (90%) and metabolism (10%).

Question 15

Compare ammonia, urea, and uric acid as nitrogenous waste products in animals.

Answer 15

-Ammonia: high toxicity, high solubility
-Urea: medium toxicity, medium solubility
-Uric acid: low toxicity, low solubility

1. Ammonia
   - commonly found in aquatic habitats
   -originates from the breakdown of proteins
   - is highly toxic
   - soluble in water.
2. Urea
   - found in both aquatic and terrestrial habitats
   - originates from the synthesis of CO2 and NH3
   - has medium toxicity
   - fairly soluble in water.
3. Uric acid
   - found in terrestrial habitats
   - originates from the synthesis of CO2, NH3, and other molecules
   - has low toxicity
   - poor solubility in water.

Question 16

what are the characteristics of Ammonia?

Answer 16

1. commonly found in aquatic habitats
2. originates from the breakdown of proteins
3. is highly toxic
4. soluble in water.

Question 17

What are the characteristics of urea?

Answer 17

1. found in both aquatic and terrestrial habitats
2. originates from the synthesis of CO2 and NH3
3. has medium toxicity
4. fairly soluble in water.

Question 18

What are the characteristics of uric acid?

Answer 18

1. found in terrestrial habitats
2. originates from the synthesis of CO2, NH3, and other molecules
3. has low toxicity
4. poor solubility in water.

Question 19

What animals use urea?

Answer 19

Fish and mammals use urea because it is less toxic and more soluble than ammonia.

Question 20

What animals use uric acid?

Answer 20

Insects and birds use uric acid because it is even less toxic and less soluble than urea.

Question 21

What animals use ammonia?

Answer 21

Aquatic invertebrates use ammonia because it is very soluble in water.

Question 22

Compare excretory process of fresh water vs salt water unicellular organisms

Answer 22

-Unicellular organisms in fresh water use diffusion and need a contractile vacuole.

-Unicellular organisms in salt water use diffusion and don’t need to excrete water.

Question 23

What is the excretory system of planarians?

Answer 23

Planarians have an excretory system composed of canals with flame cells to regulate water content.

Question 24

what is the excretory system of earthworms?

Answer 24

Earthworms have metanephridia in each body segment that collect fluid and remove waste material.

Question 25

what is the excretory system of insects?

Answer 25

Insects have Malpighian tubules to excrete waste as uric acid and reabsorb water.

Question 26

What do kidneys do?

Answer 26

Kidneys control the composition and volume of blood, maintain blood pH, and remove nitrogenous wastes.

Question 27

What do ureters do?

Answer 27

Ureters transport urine from the kidneys to the bladder.

Question 28

What does the urinary bladder do?

Answer 28

Urinary bladder stores urine and can hold up to 800 mls.

Question 29

What does the urethra do?

Answer 29

Urethra expels urine from the bladder to the outside.

Question 30

Describe the kidney?

Answer 30

1. The human kidney is reddish brown in color and shaped like a kidney bean, about 10-12 cm long and 2.5 cm thick.
2. The concave side of the kidney medial to the vertebral column has a notch called the renal hilus, which is where blood vessels, nerves, and lymph vessels enter and the ureter exits.
3. The kidney is protected by a tough, transparent fibrous outer coat called the renal capsule, which is located above the renal cortex.
4. The renal cortex is a granular layer where blood vessels contact kidney tubules, located below the renal capsule.
5. The renal medulla is the inner layer of the kidney below the renal cortex, arranged in pyramid-like structures that contain the collecting ducts that empty into a central cavity called the renal pelvis.
6. The vascular portion of the kidney arises from the renal artery, which enters the kidney in the renal hilus and branches into the interlobular arteries that carry blood to the afferent arterioles.
7. Each afferent arteriole goes to 1 Bowman’s capsule, and then divides many times to form a tangled network of capillaries within Bowman’s capsule called the glomerulus.
8. The glomerular capillaries reunite to form the efferent arterioles, which exit Bowman’s capsule and form a peritubular capillary network around the convoluted tubules (including the loop of Henle).
9. The functional unit of the kidney is called the nephron, of which there are about a million in each kidney.
10. There are two types of nephrons: cortical nephrons, which have a short loop of Henle and comprise 85% of nephrons in humans, and juxtamedullary nephrons, which have a long loop of Henle extending deep into the medulla.
11. The nephron consists of tubular and vascular portions, the tubular portion being comprised of the glomerular capsule (Bowman’s capsule) which leads to the proximal convoluted tubule, the descending loop of Henle, the ascending loop of Henle, the distal convoluted tubule, and the collecting ducts of the medulla.

Question 31

What is the renal hilus?

Answer 31

The place where blood vessels, nerves, and lymph vessels enter and the ureter exits.

Question 32

What is the renal capsule?

Answer 32

A tough, transparent fibrous outer coat located above the renal cortex that protects the kidney

Question 33

What is the renal cortex?

Answer 33

A granular layer where blood vessels contact kidney tubules, located below the renal capsule.

Question 34

What is the renal medulla?

Answer 34

The renal medulla is the inner layer of the kidney below the renal cortex, arranged in pyramid-like structures that contain the collecting ducts that empty into a central cavity called the renal pelvis.

Question 35

Describe the vascular portion of the kidney

Answer 35

The vascular portion of the kidney arises from the renal artery, which enters the kidney in the renal hilus and branches into the interlobular arteries that carry blood to the afferent arterioles.

Question 36

Where do afferent arterioles go and what do they become in regards to the kidney?

Answer 36

1. Each afferent arteriole goes to 1 Bowman’s capsule
2. divides many times to form a tangled network of capillaries
3. this is called the glomerulus.

Question 37

The glomerular capillaries reunite to form the efferent arterioles, which exit Bowman’s capsule and form a peritubular capillary network around the convoluted tubules (including the loop of Henle).

Answer 37

1. The glomerular capillaries reunite to form the efferent arterioles
2. They exit Bowman’s capsule
3. they form a peritubular capillary network around the convoluted tubules (including the loop of Henle).

Question 38

What is a nephron?