29

Question 1

4 steps of food processing

Answer 1

Ingestion, digestion, absorption, egestion

Question 2

Mouth function

Answer 2

Does physical digestion (bigger to smaller pieces) & chemical digestion (chemical bonds broken. Ex. Saliva’s enzymes)

Saliva has enzyme called amylase which digests starch. It also has mucus, which lubricates & helps with swallowing.

Question 3

Esophagus

Answer 3

Epiglottis is a small flap of tissue that closes over trachea when swallowing. Bolus (the shape) of food moves down from esophagus to stomach due to peristalsis (wave-like contractions).

Question 4

Stomach - Sphincters

Answer 4

Sphincters are circular muscles that control movement of food in & out of stomach.

Gastroesophageal sphincter controls entry of food, while pyloric sphincter controls the exit of food.

Question 5

Stomach - Layers

Answer 5

Mucosa - innermost layer made of epithelial cells that secretes gastric juice (which has enzymes, acid, & mucus)

Muscle layer - breaks down food by contracting frequently, forming chyme (semi-liquid mixture of food & gastric juice). This soupy liquid enters the small intestine.

Question 6

Stomach - Gastrin (mucus, HCI, pepsin)

Answer 6

Gastrin (hormone) helps release gastric juice from mucosa cells. Mucus coats & protects stomach lining. Hydrochloric acid (pH 2-3) kills bacteria & activates enzyme pepsin (from inactive pepsinogen), which digests proteins.

Question 7

Small intestines - Size and what parts? Also what is its purpose?

Answer 7

2.5cm in diameter, up to 7m in length.

Parts

Duodenum - first 25-30cm; for digestion

Jejunum - digestion & some absorption

Ileum - absorption

The small intestine breaks down food and absorbs nutrients.

Question 8

Small intestine - Inner surface (Villi, microvilli, lacteals)

Answer 8

Inner layers are folded into ridges. They have smaller folds/finger-like projections called villi. The villi have even smaller, microscopic projections called microvilli.

Nutrients go from mucosa in small intestine into capillary networks in villi.

These villi have network of capillaries that pick up absorbed nutrients (except digested fats). The fats are transported (absorbed) through small vessels called lacteals.

Question 9

Chemical Digestion in Small Intestine (Duodenum) (Chyme > Prosecretin, Secretin, CCK)

Answer 9

Acidic chyme enters duodenum (through pyloric sphincter), and epithelial cells convert prosecretin to secretin. Fat in chyme causes the release of hormone CCK (cholecystokinin).

Question 10

Role of Pancreas in Small Intestine - The hormones & enzymes they release (HCO3- ions, trypsinogen, trypsin, enterokinase, lipases)

Answer 10

Secretin (hormone) stimulates pancreas to release HCO3- (bicarbonate ions). These ions have a pH of 9, which inactivates the pepsin in chyme. The ions travel from pancreas to pancreatic duct and then into duodenum.

The hormone CCK (from duodenum) releases pancreatic juice (containing digestive enzymes & HCO3- ions) that signals the stomach to slow down digestion.

Pancreas also releases trypsinogen, which activates into trypsin (enzyme, after travelling from pancreas into duodenum, helps digest protein) by enzyme enterokinase.

It also releases lipases (enzyme), which help break down lipids (fats). Digested fats are absorbed through lacteals.

Question 11

Role of Liver and Gall Bladder in Small Intestine

Answer 11

The liver creates bile which is stored in the gall bladder. Bile is a substance that emulsifies (breaks) fat down into smaller pieces (physical digestion).

Question 12

Absorption in Small Intestine

Answer 12

In jejunum & ileum, through…

Passive transport - movement of materials across a cell membrane without use of energy. Uses osmosis (movement of water from area with more water to area with less water) and facilitated diffusion (diffusion of molecules across membrane through transport proteins). Moves materials down concentration gradient.

Active transport - movement of materials across a cell membrane with use of energy. Moves materials up concentration gradient.

Question 13

Large intestine - Size and what parts? Also what is its purpose?

Answer 13

7.6cm in diameter, 1.5m in length. Cecum (with appendix) is the start of the large intestine, and is a pouch that receives material from small intestine.

Colon has 4 segments, and is the longest part.

There is also the rectum (last 20cm of large intestine) and the anus (the external opening).

The large intestine absorbs water & produces essential vitamins.

Question 14

Egestion - What happens? Also, what is the role of dietary fiber in human egestion?

Answer 14

Rectum holds waste until eliminated as feces through anus.

Dietary fiber helps prevent/relieve constipation.

Question 15

What are the 4 components of the digestive process?

Answer 15

ingestion, digestion, absorption, egestion

Question 16

What enzyme is present in saliva? What nutrient does it digest?

Answer 16

amylase; It starts the digestion of starch (a carbohydrate).

Question 17

What is the food called as it leaves the mouth? as it leaves the stomach?

Answer 17

bolus; chyme

Question 18

In the human gastrointestinal tract, physical (mechanical) digestion of nutrients occurs in 2 different locations. Describe what happens in each of these locations.

Answer 18

-mouth: teeth chew food

-stomach: muscles contract frequently to break apart food

(Could also add small intestine, but it only applies to lipids: bile emulsifies fat)

Question 19

What causes the food to move down the esophagus?

Answer 19

peristalsis (rhythmic contractions of muscles)

Question 20

What 2 structures increase the internal surface area of the small intestine by 500 times?

Answer 20

(folds &) villi, microvilli

Question 21

Name all of the organs that food passes through (in order) in the human digestive system, starting with the mouth.

Answer 21

mouth, esophagus, stomach, small intestine, large intestine, anus

Question 22

Name 3 accessory organs to the digestive system.

Answer 22

any 3 of: liver, pancreas, gall bladder, salivary glands

Question 23

Name the 2 muscles that allow food into and out of the stomach.

Answer 23

gastroesophageal sphincter & pyloric sphincter

Question 24

What are the 3 components of the gastric juice in the stomach and what do they do?

Answer 24

mucus: protects the lining of the stomach from acid & enzymes

hydrochloric acid: kills pathogens, activates pepsinogen

pepsinogen: when activated (to pepsin), it digests proteins

Question 25

Name 2 hormones secreted by the cells of the duodenum.

Answer 25

secretin (it signals the liver + pancreas) & cholecystokinin (CCK) (signals the pancreas + stomach)

Question 26

The presence of acid in the duodenum (small intestine) causes a chemical signal to be sent to the pancreas. What does the pancreas release that neutralizes the acid?

Answer 26

bicarbonate ions

Question 27

Name 3 digestive enzymes that are secreted into the duodenum.

Answer 27

Any 3 of: -enterokinase (converts trypsinogen to trypsin) -trypsin (digests proteins) -lipase (breaks down fats) -amylase (digests starch) -carboxypeptidase -erepsins (digests proteins)

Question 28

What is 1 main function of the large intestine?

Answer 28

Any 1 of: water absorption; vitamin & ion absorption; home to important bacteria

Question 29

What are the 3 sections of the small intestine? What part of the digestive process occurs only in the last 2 sections?

Answer 29

duodenum, jejunum & ileum; absorption of nutrients occurs here

Question 30

Where is bile produced, and where is it stored?

Answer 30

bile is produced in the liver, stored in the gall bladder

Question 31

Diaphragm, external/internal intercostal muscles, pleural membranes

Answer 31

Diaphragm - large sheet of muscle located beneath lungs that is the primary muscle in breathing External intercostal muscles - for normal breathing - muscles that raises ribcage, decreasing pressure in chest cavity Internal intercostal muscles - for strenuous exercise or forced exhalation - muscle that pulls ribcage downward, increasing pressure in chest cavity Pleural membranes - Protective 2 layers surrounding the lungs

Question 32

Ventilation and what does diaphragm & external/internal intercostal muscles do during ventilation

Answer 32

Ventilation - process of getting air to the respiratory system Diaphragm, external & internal intercostal muscles change the volume & pressure in the chest cavity. Air moves from high to low pressure.

Question 33

Lung capacity diagram terms...

Answer 33

Total lung capacity: Maximum volume of air that can be inhaled Tidal volume: Volume of air inhaled or exhaled during a normal, involuntary breath. In average adult = 0.5 L Inspiratory reserve volume: Volume of air that can be forcibly inhaled after a normal inhalation. Expiratory reserve volume: Volume of air that can be forcibly exhaled after a normal exhalation. Residual volume: Volume of air remaining in lungs after a forced exhalation Vital capacity: Maximum amount of air that can be inhaled or exhaled

Question 34

Function of hemoglobin

Answer 34

Hemoglobin is the protein that carries 98.5% of the oxygen in our blood cells. The other 1.5% is dissolved in the liquid part of the blood. Oxygen diffuses from alveoli into liquid part of blood & blood cells. Hemoglobin increases blood's capacity to carry oxygen by nearly 70 times as without it! It also binds with molecules of oxygen to form oxyhemoglobin, which gives oxygenated blood its bright red colour (deoxygenated is dark red)

Question 35

How O2 and CO2 are carried in blood

Answer 35

Oxygen: Diffuses from alveoli into blood plasma and then into blood cells Carbon dioxide: 73% forms carbonic acid, 20% attaches to hemoglobin, 7% dissolved in plasma

Question 36

How do pressure & volume affect inhalation?

Answer 36

When you inhale, the volume of the chest cavity is increased & the pressure inside your lungs is lower. The higher pressure air outside flows in to lower pressure in chest cavity.

Question 37

If you breathe in normally, then exhale normally into a spirometer, what lung volume are your measuring?

Answer 37

tidal volume

Question 38

If you breathe in as deeply as you can, then exhale as much as you can into a spirometer, what lung volume are your measuring?

Answer 38

vital capacity

Question 39

What is the main function of hemoglobin?

Answer 39

The main function of hemoglobin is to carry oxygen.

Question 40

Flow of blood in pulmonary circuit & systemic circuit

Answer 40

Blood circulation to the lungs (short loop called pulmonary circuit) can be separated from blood circulation to the rest of the body (systemic circuit) with more heart chambers

Question 41

Components of blood

Answer 41

Plasma (55%) - Has protein-rich liquid which is 90+% water. Also has serum, the fluid part of plasma. Red blood cells (45%) - Called erythrocytes. They carry oxygen & carbon dioxide, are biconcave, have no nucleus so that there is more space for hemoglobin, and the lifespan is 120 days. White blood cells & platelets (<1%) - Called leukocytes. Part of the immune system. It defends body against harmful substances/organisms.

Question 42

Septum

Answer 42

Wall of tissue dividing left & right ventricles

Question 43

Pericardium

Answer 43

Fluid-filled sac that surrounds and protects the heart

Question 44

Coronary blood vessel

Answer 44

A blood vessel that circulates blood to and from the muscle cells of the heart

Question 45

Chambers

Answer 45

The right atrium receives oxygen-poor blood from the body and pumps it to the right ventricle. The right ventricle pumps the oxygen-poor blood to the lungs. The left atrium receives oxygen-rich blood from the lungs and pumps it to the left ventricle. The left ventricle pumps the oxygen-rich blood to the body.

Question 46

Coronary arteries/blood vessels Also, what causes heart sounds???

Answer 46

Supply blood to heart tissue Heart sounds are caused by the closing of heart valves

Question 47

Semilunar valves

Answer 47

Prevents backflow of blood when ventricles relax Ex. Mitral & Aortic valves

Question 48

Atrioventricular valves + chordae tendineae

Answer 48

Prevents blood flow of blood from ventricles to atriums. Supported by chordae tendineae - tendons that support the atrioventricular valves Ex. Pulmonary & tricuspid valves

Question 49

Diastole & systole

Answer 49

The cardiac cycle is a complete heartbeat where atria (atriums) & ventricles contract and relax. There are 2 phases... Diastole - when ventricles are relaxed and filled up by blood Systole - when ventricles contract and emptied of blood

Question 50

What are the 2 main components of blood? What percentage of each?

Answer 50

55% plasma 45% blood cells (mostly red blood cells)

Question 51

Describe 2 characteristics of erythrocytes (red blood cells).

Answer 51

Any 2 of: RBC's have no nucleus; they contain hemoglobin, which carries oxygen; they are red when they carry oxygenated blood and blue when they carry deoxygenated blood; they make up almost all of the cells in blood; they are biconcave; they survive about 120 days....

Question 52

Name 1 type of protein contained in blood. Also what cell is involved in blood clotting?

Answer 52

Any 1 of: albumins, globulins, fibrinogens Platelets

Question 53

Name the 2 major blood vessels that bring blood to the heart.

Answer 53

the vena cava (superior & inferior), and the pulmonary veins

Question 54

Name the 2 major blood vessels that take blood away from the heart.

Answer 54

the aorta & the pulmonary arteries

Question 55

What is systolic blood pressure?

Answer 55

blood pressure while the ventricles in the heart are contracting

Question 56

What causes the "lubb-dubb" sounds of the heartbeat?

Answer 56

the closing of the heart valves