Lecture 24

Question 1

Primary function of digestive system

Answer 1

Supply nutrients from food to blood -> cells

Question 2

Processes enabling digestive syst to work are

Answer 2

1. Ingestion
2. Propulsion
3. Mechanical digestion
4. Chemical digestion
5. Absorption
6. Defecation

Question 3

2 main categories of digestive system

Answer 3

1. GI tract
2. Accessory structures

Question 4

GI tract is

Answer 4

Tube open at both ends for transit of food during processing

Question 5

GI tract includes

Answer 5

Mouth
Esophagus
Stomach
Small/large intestines

Question 6

Accessory structures do what

Answer 6

Contribute to food processing

Question 7

Accessory structures include

Answer 7

Teeth
Tongue
Salivary glands
Liver
Gallbladder
Pancreas

Question 8

Mechanical digestion is

Answer 8

Physical breakdown of food

Question 9

Two sites of mechanical digestion

Answer 9

1. Mouth
2. Stomach (most happens in it)

Question 10

Mouth mechanical digestion

Answer 10

Teeth/tongue breakdown food in smaller pieces by chewing, grinding, cutting, mixing etc (mastication)

Question 11

Stomach mechanical digestion

Answer 11

Contraction of various layers of smooth muscle grind food in smaller pieces, help mix food with acidic gastric juices

Question 12

Chemical digestion is

Answer 12

Chemical breakdown of larger into smaller molecules using enzymes

Question 13

Reason for chemical digestion

Answer 13

Intestinal lining can only absorb very small molecules

Question 14

Locations of chemical digestion

Answer 14

1. Mouth
2. Stomach
3. First section of small intestine (duodenum)

Question 15

Mouth chemical digestion

Answer 15

Digestive enzyme in saliva (amylase) that breaks down carbs into smaller sugars

Question 16

Stomach chemical digestion

Answer 16

Enzyme in gastric juices (pepsin) breaks down prots into amino acids

Question 17

Duodenum chemical digestion

Answer 17

Food chemically broken down by pancreas secreted enzymes (majority of chem digestion occurs here)

Question 18

Esophagus is

Answer 18

Long tube of smooth muscle from larynx to stomach that moves food from mouth to stomach

Question 19

Act of swallowing causes

Answer 19

Epiglottis to rise and block food entry to trachea

Question 20

Stomach

Answer 20

Primarily smooth muscle, contraction physically breaks food (mechanical) and pepsin chemically breaks down prots

Question 21

Gastric juice in stomach made of

Answer 21

Pepsin and acid

Question 22

Small intestine

Answer 22

Longest portion of gi, 3 subdivisions, chemical digestion in duodenum (using enzymes from pancreas)
after duodenum, main function is allow small nutrients to cross into bv (absorption) to transport to cells

Question 23

Liver main role in digestive system

Answer 23

Secrete bile into duodenum

Question 24

Bile’s main role

Answer 24

Help break globs of fat into smaller droplets so easier for pancreatic enzymes to chemically break down into fatty acids

Question 25

Gallbladder

Answer 25

Muscular sac storing excess bile, releases extra bile when eat food very fatty

Question 26

Fat is hydrophobic so tends to stick together, bile basically

Answer 26

Forces fat molecules apart

Question 27

Since small intestines function is absorption, mucosa structured to

Answer 27

Increase surface area (more contact with substances)

Question 28

How is small intestine surface area increased

Answer 28

Walls folded into villi, which have cells (columnar epithelium) with microvilli lining each villus

Question 29

Large intestine receives

Answer 29

Substances not absorbed by small (cannot be broken down/digested/absorbed, so excreted)

Question 30

Major roles of large intestine

Answer 30

1. Absorbs as much water as it can from unabsorbed material 2. Prepare this material for excretion

Question 31

Rectum (last segment of large intestine)

Answer 31

When material enter rectum, referred to as feces, where feces are stored until evacuation

Question 32

Composition of water of feces

Answer 32

75% (despite large water amount absorbed by large intestine)

Question 33

Other substances found in feces

Answer 33

1. Bacteria (mostly from gut microbiota) 2. Indigestible material (ex dietary fiber/cellulose) 3. Fat (can be high after fat meals or lack of bile production) 4. Cholesterol

Question 34

Urinary system primary functions

Answer 34

1. Removal of waster products from blood 2. Blood volume regulation and water balance

Question 35

Urinary syst secondary functions

Answer 35

1. Storage of urine (bladder) 2. Excretion of urine (via urethra)

Question 36

Urinary syst includes

Answer 36

1. 2 kidneys (filter blood/create urine) 2. 2 ureters (bring urine from kid to bladder) 3. Urinary bladder (storage) 4. Urethra (allows urine excretion)

Question 37

Urethra male vs female

Answer 37

Longer in male passes through penis, base surrounded by prostate

Question 38

What is a nephron

Answer 38

Microscopic tubes in kidneys

Question 39

Nephrons do what

Answer 39

1. Each removes portion of waste from blood 2. Getting rid of any excess water in body 3. Fluid leaving a nephron is waste and water, called urine

Question 40

How does the urge to urinate occur

Answer 40

When walls of bladder stretch to a certain point, signal sent to cortex