Lab 8: Animal Biology: Excretory and Digestive Systems

Question 1

Briefly summarise the function of the following organ: mouth

Answer 1

mechanical digestion, starts the break down of starch

Question 2

Briefly summarise the function of the following organ: esophagus

Answer 2

passageway for bolus that connects to the stomach

Question 3

Briefly summarise the function of the following organ: stomach

Answer 3

breaks down food mechanically and chemically

Question 4

Briefly summarise the function of the following organ: small intestine

Answer 4

absorbs the bulk of nutrients

Question 5

Briefly summarise the function of the following organ: large intestine

Answer 5

absorbs water and other small nutrients

Question 6

Briefly summarise the function of the following organ: rectum

Answer 6

temporarily stores feces

Question 7

Briefly summarise the function of the following organ: anus

Answer 7

exit source for waste

Question 8

Briefly summarise the molecules the following organ secretes/ releases: pancreas

Answer 8

secretes enzymes and sodium bicarbonate to neutralize chyme

Question 9

Briefly summarise the molecules the following organ secretes/ releases: liver

Answer 9

secretes bile

Question 10

Briefly summarise the molecules the following organ secretes/ releases: salivary glands

Answer 10

secretes salivary amylase which breaksdown starch

Question 11

Briefly summarise the molecules the following organ secretes/ releases: gall bladder

Answer 11

secretes excess bile

Question 12

name the 3 tubes that connect to each kidney

Answer 12

• ureter
• renal artery
• renal vein

Question 13

Describe the following for the ureter:

• what the tube contains
• which organs these contents came from
• which organ these contents are going to next

Answer 13

• urine
• kidneys
• urinary bladder

Question 14

Describe the following for the renal artery:

• what the tube contains
• which organs these contents came from
• which organ these contents are going to next

Answer 14

• oxygenated blood
• abdominal aorta
• kidney tissue

Question 15

Describe the following for the renal vein:

• what the tube contains
• which organs these contents came from
• which organ these contents are going to next

Answer 15

• deoxygenated blood
• kidney
• inferior vena cava

Question 16

How does the excretory system help you maintain homeostasis when you’re dehydrated? Why is your urine darker coloured when you are thirsty?

Answer 16

the kidneys regulate water levels in urine depending on the needs of the body. When we intake less water we are in shortage of water and less will exit in urine. If we are intake more water than necessary at the time, we will be in a surplus and more will exit in the urine. This is why sometimes urine becomes darker because it gets very concentrated when we are dehydrated.

Question 17

Explain what happened to the other 158.5 litres of fluid that entered the nephron as glomerular filtrate?

Answer 17

Kidneys regulate water levels by conserving water if you’re dehydrated or diluting urine to expel water if necessary

Question 18

1.5 litres is still a large volume of fluid for a human being to lose every day. Explain how we replenish this water that we lost from our bodies.

Answer 18

we intake fluid (drinking water!)

water is absorbed by the large intestine

Question 19

Explain why there is no protein in the glomerular filtrate or the urine

Answer 19

kidneys filter what goes into the urine and proteins are too big to pass through this filter. their molecules are too big

Question 20

Explain why glucose concentrations are 120mg/100mL in the blood entering and exiting the glomerulus and the glomerular filtrate but absent in the urine.

Answer 20

the kidneys absorb all the glucose and return it to the blood stream

Question 21

explain why urea concentrations are 30mg/100ml in the blood entering and exiting the glomerulus and in the glomerular filtrate but are 2000mg/100ml in the urine

Answer 21

• urea is a byproduct of the breakdown of nitrogen containing compounds and considered waste in the body. it exits through our urine

Question 22

Explain the differences in concentration between the arterial blood entering the glomerulus and venous blood exiting the kidney for each solute in table B2. See google doc for table

Answer 22

• proteins: kidneys produce hormones (some are proteins); therefore more leave than enter. proteins cant leave through urine or glomerular filtrate because it is too large
• glucose: kidneys maintain homeostasis by increasing or decreasing the amount of water in urine. the fluid maintenance allows blood glucose levels to maintain consistent
• urea: levels of urea maintained by kidneys which filter it out of body

Question 23

list in sequential order the enzymes involved with digesting starch into simple sugars. for each enzyme (3) name the oran that produces it and the locations where it is active in digesting food.

Answer 23

1. salivary amylase: found in the mouth; produced by salivary glands
2. maltase: found in the duodenum; produced by pancreas
3. pancreatic amylase: found in the small intestine; produced by pancreas

Question 24

list in sequential order the enzymes involved with digesting protein into amino acids. for each enzyme, name the organ that produces it, and the locations where it is active in digesting food (3)

Answer 24

1. pepsin: found in stomach; produced by stomach glands
2. trypsin: small intestine; produced by pancreas
3. peptidases: found in small intestine; produced by small intestine

Question 25

list in sequential order the enzymes involved with digesting DNA/RNA into nitrogenous bases sugars and phosphates. for each enzyme name the organ that produces it, and the locations where it is active in digesting food (2)

Answer 25

1. nuclease: active in small intestine; produced by pancreas | 2. nucleosidase: active in small intestine; produced by small intestine

Question 26

list in sequential order the enzymes involved with digesting fats into fatty acids and glycerol. for each enzyme name the organ that produces it, and the locations where it is active in digesting food (2)

Answer 26

1. lingual lipase: active in the mouth; produced by salivary glands 2. pancreatic lipase: active in duodenum; produced by pancreas

Question 27

give at least 2 reasons why more than 1 enzyme is necessary for digesting most types of biological molecules

Answer 27

- the breakdown of food is complex, requires multiple steps and multiple enzymes (catabolic pathway) - depending on the biological molecule; more than 1 enzyme may be necessary if the digestion needs to happen fast

Question 28

define: excretion

Answer 28

process by which the body removes nitrogenous waste products, deactivated drugs, toxins, and excess solutes from the body

Question 29

define: homeostasis

Answer 29

state of steady internal, physical, and chemical conditions maintained by living systems

Question 30

define: osmoregulation

Answer 30

process by which the body balances the intake and loss of water and solutes

Question 31

define: water intoxication

Answer 31

consuming too much water and losing too many salts through sweating

Question 32

Explain the 4 functional steps of nephrons

Answer 32

- see google doc

Question 33

State the enzymes produced in the salivary glands and what their function is (2)

Answer 33

- salivary amylase: breaks apart carbs releasing sugars in the mouth - lingual lipase: breaks bonds in fats releasing fatty acids and monoglycerides in mouth and stomach

Question 34

State the enzymes produced in the stomach and what their function is (1)

Answer 34

- pepsin: break peptide bonds between certain amino acids in proteins releasing polypeptides

Question 35

State the enzymes produce din the pancreas and what their function is (7)

Answer 35

- carboxypeptidase and chymotrypsin and elastase: breaks peptide bonds in polypeptides releasing amino acids in the small intestine - nucleases: break apart nucleic acids in the small intestine releasing nucleotides - pancreatic amylase: break apart carbohydrates in the small intestine releasing sugars - pancreatic lipase: break bonds in fats releasing fatty acids and monoglycerides in small intestines - trypsin: break specific peptide bonds in polypeptides releasing amino acids in small intestine

Question 36

State the structures food passes through in the human body (7)

Answer 36

- mouth - esophagus - stomach - small intestine - cecum - large intestine - anus

Question 37

Trace the path of a single molecule of hemoglobin | coming in through the renal artery.

Answer 37

- renal artery, cortex, medulla, renal vein

Question 38

In which region of the kidney is | blood filtered to form filtrate?

Answer 38

- renal corpuscle (located in the cortex)

Question 39

Which region of the kidney has a high osmolarity (i.e., concentration of solutes) that draws water out of the nephron through osmosis? Which two solutes are primarily responsible for creating this osmolarity gradient?

Answer 39

- interstitial fluid in the medulla | - Na+ and Cl-

Question 40

Name the microscopic tubes that “collect’ urine from many nephrons and deliver this urine into the renal pelvis

Answer 40

- renal calyces