Exam 3 (Chapters 24-27)

Question 1

What are the GI tract (aka, alimentary canal) organs?

Answer 1

Mouth, most of pharynx, esophagus, stomach, small intestine and large intestine.

Question 2

What are the accessory digestive organs?

Answer 2

Teeth, tongue, salivary glands, liver, gallbladder and pancreas.

Question 3

Organs of the Digestive System

Answer 3

Organs of the Digestive System

Question 4

What are the six functions of the digestive system?

Answer 4

1. Ingestion (taking in foods and liquids) 2. Secretion (of water, acid, buffers and enzymes into lumen) 3. Mixing and Propulsion (motility) 4. Digestion (mechanical digestion churns food; chemical digestion - hydrolysis) 5. Absorption (entrance of ingested and secreted liquids, ions and digestive products into blood or lymph) 6. Defecation (elimination of feces)

Question 5

Layers of the GI Tract

Answer 5

Layers of the GI Tract

Question 6

Neural Innervation of the GI Tract: Enteric Nervous System (ENS)

Answer 6

• Intrinsic set of nerves (“brain of gut”) - Neurons extending from esophagus to anus - Plexuses: myenteric plexus (GI tract motility) and submucosal plexus (controlling secretions)

Question 7

Neural Innervation of the GI Tract: Autonomic Nervous System (ANS)

Answer 7

• Extrinsic set of nerves - Parasympathetic stimulation: increases secretion and activity by stimulating ENS. - Sympathetic stimulation: decreases secretions and activity by inhibiting ENS.

Question 8

Peritoneal Folds

Answer 8

Peritoneal Folds

Question 9

Deglutition (Swallowing)

Answer 9

Deglutition (Swallowing)

Question 10

External and Internal Anatomy of the Stomach

Answer 10

External and Internal Anatomy of the Stomach

Question 11

Mechanical Digestion in the Stomach

Answer 11

Mixing waves - gentle, rippling peristaltic movements - creates chyme

Question 12

Chemical Digestion in the Stomach: Salivary Amylase

Answer 12

Salivary amylase: - digestion continues until inactivated by acidic gastric juice

Question 13

Chemical Digestion in the Stomach: Lingual Lipase

Answer 13

Lingual lipase: - acidic gastric juice activates lingual lipase - digest triglycerides into fatty acids and diglycerides

Question 14

Chemical Digestion in the Stomach: HCl

Answer 14

HCl - Parietal cells secrete H+ and Cl- separately but net effect is HCl - Kills many microbes, denatures proteins

Question 15

Chemical Digestion in the Stomach: Pepsin

Answer 15

Pepsin - Secreted by chief cells - Secreted as inactive pepsinogen - Digests proteins

Question 16

Chemical Digestion in the Stomach: Gastric Lipase

Answer 16

Gastric Lipase - Splits triglycerides into fatty acids and monoglycerides

Question 17

Absorption in the Stomach

Answer 17

• Small amount of nutrient absorption - Some water, ions, short chain fatty acids, certain drugs (aspirin) and alcohol.

Question 18

Relation of the Pancreas to the Liver, Gallbladder, and Duodenum

Answer 18

Relation of the Pancreas to the Liver, Gallbladder, and Duodenum

Question 19

The Liver

Answer 19

The Liver

Question 20

Gallbladder

Answer 20

• A pear-shaped sac in the posterior surface of the liver - Contraction of smooth muscle fibers eject contents of gall bladder into cystic duct - Functions to store and concentrate bile produced by the liver until it is needed in the small intestine - Absorbs water and ions to concentrate bile up to ten-fold

Question 21

Other Crucial Functions of the Liver

Answer 21

• Carbohydrate, lipid and protein metabolism - Processing of drugs and hormones - Storage - Phagocytosis - Activation of Vitamin D

Question 22

Anatomy of the Small Intestine

Answer 22

Anatomy of the Small Intestine

Question 23

Chemical Digestion in the Small Intestine: Carbohydrates

Answer 23

• pancreatic amylase - ɑ-dextrinase of the brush border acts on ɑ-dextrins - common disaccharides are not acted on until the small intestine—sucrose, maltose and lactose

Question 24

Chemical Digestion in the Small Intestine: Proteins

Answer 24

• trypsin, chymotrypsin, carboxypeptidase, and elastase from pancreas - aminopeptidase and dipeptidase in brush border

Question 25

Daily Volumes of Fluid Ingested, Secreted, Absorbed and Excreted from the GI tract 

Answer 25

Daily Volumes of Fluid Ingested, Secreted, Absorbed and Excreted from the GI tract 

Question 26

Daily Volumes of Fluid Ingested, Secreted, Absorbed and Excreted from the GI Tract: Ingested and Secreted

Answer 26

- Saliva (1 liter) - Ingestion of liquids (2.3 liters) - Gastric juice (2 liters) - Bile (1 liter) - Pancreatic juice (2 liters) - Intestinal juice (1 liter) Total ingested and secreted = 9.3 liters

Question 27

Daily Volumes of Fluid Ingested, Secreted, Absorbed and Excreted from the GI Tract: Absorbed

Answer 27

- Small intestine (8.3 liters) - Large intestine (0.9 liters) Total absorbed = 9.2 liters

Question 28

Daily Volumes of Fluid Ingested, Secreted, Absorbed and Excreted from the GI Tract: Excreted

Answer 28

- Excreted in feces (0.1 liter)

Question 29

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Answer 29

Anatomy of the Large Intestine %20Anatomy%20of%20the%20Large%20Intestine.jpg)

Question 30

Anatomy of the Large Intestine (continued) %20Anatomy%20of%20the%20Large%20Intestine%20B.jpg)

Answer 30

Anatomy of the Large Intestine (continued) %20Anatomy%20of%20the%20Large%20Intestine%20B.jpg)

Question 31

Metabollism

Answer 31

All chemical reactions occuring in the body.

Question 32

Catabolism

Answer 32

Catabolism = breaking down of complex molecules. Catabolism is exergonic—it produces more energy than it consumes.

Question 33

Anabolism

Answer 33

Anabolism = combine simple molecules to create complex molecules Anabolism is *ender*gonic = consuming more energy than it produces

Question 34

Adenosine Triphosphate (ATP)

Answer 34

ATP = "energy currency" ADP + P + energy ⇔ ATP

Question 35

Energy Transfer

Answer 35

Energy transfer is accomoplished through oxidation-reduction (REDOX) reactions.

Question 36

Oxidation

Answer 36

* Removal of electrons * Decrease in potential energy * Dehydrogenation (removal of hydrogens) * Liberated H is transferred by coenzymes * EXAMPLES: * Nicotinamide adenine dinucleotide (NAD) * Flavin adenine dinucleotide (FAD) * Glucose is commonly oxidized to yield energy

Question 37

Overview of Cellular Respiration 

Answer 37

Overview of Cellular Respiration 

Question 38

Glycolysis Reactions 

Answer 38

Glycolysis Reactions 

Question 39

The Krebs Cycle is also known as...

Answer 39

The Krebs Cycle is also known as the **citric acid cycle**

Question 40

Where does the Krebs cycle occur?

Answer 40

In the matrix of the mitochondria

Question 41

What is the Krebs cycle?

Answer 41

A series of REDOX reactions.

Question 42

What are the important processes and steps of the Krebs cycle?

Answer 42

* 2 decarboxylation reactions release CO₂ * **Reduced coenzymes (NADH and FADH₂) are the most important outcome** * One molecule of ATP generated by substrate-level phosphorylation

Question 43

Chemiosmosis 

Answer 43

Chemiosmosis 

Question 44

Glycogenesis and Glycogenolysis 

Answer 44

Glycogenesis and Glycogenolysis 

Question 45

Lipoproteins - How are they categorized and named?

Answer 45

Lipoprotiens are categorized and named according to **density** (ratio of lipids to proteins)

Question 46

Lipoproteins - Chylomicrons

Answer 46

* Forms in *small intestine mucosal epithelial cells* * Transport *dietary lipids* to *adipose tissue*

Question 47

Lipoproteins - Very Low-Density Lipoproteins (VLDLs)

Answer 47

* Forms in *hepatocytes* * Transport *endogenous lipids* to *adipocytes*

Question 48

Low-Density Lipoproteins (LDLs)

Answer 48

* "bad" cholesteral * **Carry 75% of total cholesterol in blood** * *Deliver to body cells for repair and synthesis* * Can deposit cholesterol in fatty plaques.

Question 49

High-Density Lipoproteins (HDLs)

Answer 49

* "good" cholesteral * **Remove excess cholesterol from body cells and blood** * *Deliver to liver for elimination*

Question 50

Lipid catabolism (lipolysis)

Answer 50

* Triglycerides split into glycerol and fatty acids * Must be done in muscle, liver, and adipose tissue to oxidise fatty acids * Enhanced by epinephrine and norepinephrine

Question 51

Lipid anabolism (lipogenesis)

Answer 51

* Liver cells and adipose cells can synthesize lipids from glucose or amino acids * Occurs when more calories are consumed than needed for ATP production.

Question 52

Postabsorptive State Reactions Glucose related reactions: After the glucose from a meal has been absorbed, eventually the supply of glucose available in the blood becomes depleted. How can the body produce new glucose?

Answer 52

* Breakdown of liver glycogen *(our major source of stored carbohydrates)* * Lipolysis (breaking down lipids) * **Note:** the fatty acid chains cannot become glucose, but the glycerol portion of a triglyceride can) * Gluconeogenesis using lactic acid * Gluconeogenesis using amino acids

Question 53

Postabsorptive State Reactions - *Non-*glucose related reactions

Answer 53

* Oxidation of fatty acids * Oxidation of lactic acid * Oxidation of amino acids * Breakdown of muscle glycogen

Question 54

Body Temperature Homeostasis - Overview

Answer 54

Despite wide fluctuations in environmental temperatures, homeostatic mechanisms maintain normal range for internal body temperature.

Question 55

Body Temperature Homeostasis - What is the body's core temperature and shell temperature?

Answer 55

Core temperature = **37ºC** (or **98.6ºF**) vs. Shell temperature = *1-6ºC lower than core temp.*

Question 56

Body Temperature Homeostasis - Heat Production Methods

Answer 56

* **Exercise** * *A fit individual can increase heat production by 15-20 times greater than resting metabolic rate through exercise.* * Hormones * **Sympathetic Nervous System** * *Release of epinephrine and norepinephrine (via sympethetic activation - e.g., caused by a stressor or during exercise) increases metabolic rate.* * Fever * **Ingestion of food** * *Food induced thermogenesis can be anywhere between 10-20% above basal metabolic rate. **The highest gain (20%) is after a protein-rich meal**; **the lowest (10%) is after a carbohydrate-rich meal.*** * Young age

Question 57

Heat Loss - Conduction

Answer 57

Heat lost through conduction(e.g., to clothing surrounding the body), at rest, is only about 3% of the body's heat.

Question 58

Heat Loss - Convection

Answer 58

* Convection = movement of a gas or liquid (e.g., the body moving air) * Typically we lose about 15% of our heat to the surrounding air

Question 59

Heat Loss - Radiation

Answer 59

* Radiation = transfer of heat in the form of infrared rays (think night vision goggles/thermal imaging?) * **A resting person in a 70ºF room loses about 60% of their heat through radiation *****at rest**.* * *This is our most important way of losing heat.*

Question 60

Heat Loss - Evaporation

Answer 60

* Evaporation of sweat from the surface of the skin * ***At rest*, a person only loses about 20% of their heat* *through evaporation.** * *During exercise, this becomes the most important method of heat loss (cooling).*

Question 61

Heat and Energy Balance - Hypothalamic thermostat is...

Answer 61

* Located in the preoptic area * It is the heat-losing (cooling) center and heat-promoting (warming) center.

Question 62

Vitamins are...?

Answer 62

Organic nutrients required in small amounts to maintain growth and normal metabolism.

Question 63

Vitamins do not...?

Answer 63

Vitamins do not provide energy or serve as building materials for the body.

Question 64

Most vitamins are...?

Answer 64

Coenzymes.

Question 65

Most vitamins cannot be...?

Answer 65

Most vitamins cannot be synthesized by the body.

Question 66

How is vitamin K produced?

Answer 66

Vitamin K is produced by bacteria in the GI tract.

Question 67

Some vitamins can be assembled from...what?

Answer 67

Some vitamins can be assembled from provitamins. Provitamin: a precursor of a vitamin, convertible into the vitamin in an organism *EXAMPLE:* ergosterol is a provitamin of vitamin D

Question 68

Vitamins are placed in one of two groups, depending on whether they are...?

Answer 68

Vitamins are grouped based on whether they are... **fat-soluble (*A, D, E, K*)** or **water-soluble (*several B vitamins and vitamin C*)**

Question 69

What functions does the kidney perform?

Answer 69

* **Regulation of blood ionic concentration** * *(most important ions = Na⁺, K⁺, Ca²⁺, Cl^- and HPO4^2- [phosphate ions])* * **Regulation of blood pH** * *(via secretion of H+ into urine and conservation of HCO3- [bicarbonate ions], which are an important buffer of H+ in the blood. Normal blood pH is 7.4 +/- 0.2)* * **Regulation of blood volume** * (inc. BV = inc. in BP; kidneys inc. or dec. BV by conserving or eliminating water in the urine) * **Regulation of blood pressure** * *Also:* * Maintenance of blood osmolarity * Production of hormones (Calcitrol [the active form of vitamin D] and erythropoietin) * Regulation of blood glucose level * Excretion of wastes from metabolic reactions and foreign substances (drugs or toxins)

Question 70

Internal Anatomy of the Kidneys: Renal Cortex - superficial

Answer 70

* outer cortical zone * inner juxtamedullary zone * renal columns—portions of cortex that extend between renal pyramids

Question 71

Internal Anatomy of the Kidneys: Renal Medulla - inner region

Answer 71

* several cone-shaped renal pyramids—base faces cortex and renal papilla points toward hilum

Question 72

Internal Anatomy of the Kidneys: Renal Lobe

Answer 72

* renal pyramid; overyling cortex area and half of each adjacent renal column

Question 73

Internal Anatomy of the Kidneys (A) %20Internal%20Anatomy%20of%20the%20Kidneys%20A.jpg)

Answer 73

Internal Anatomy of the Kidneys (A) %20Internal%20Anatomy%20of%20the%20Kidneys%20A.jpg)

Question 74

Internal Anatomy of the Kidneys (B) %20Internal%20Anatomy%20of%20the%20Kidneys%20B.jpg)

Answer 74

Internal Anatomy of the Kidneys (B) %20Internal%20Anatomy%20of%20the%20Kidneys%20B.jpg)

Question 75

Cortical Nephrons - Overview

Answer 75

* Cortical nephrons **comprise 80-85% of nephrons** * Renal corpuscle *located in outer portion of cortex* and ***short loops of Henle** extend only into outer region of medulla*

Question 76

Cortical Nephrons - Flow 

Answer 76

Cortical Nephrons - Flow 

Question 77

Juxtamedullary Nephrons - Overview

Answer 77

* Juxtamedullary nephrons **comprise the other _15_-20% of nephrons** * *Renal corpuscle is **deep in cortex*** and ***long loops of Henle** extend deep into medulla* * Receive blood from peritubular capillaries and vasa recta * Ascending limb has thick and thin regions * ***_Enable kidneys to secrete either very dilute or very concentrated urine._***

Question 78

Juxtamedullary Nephrons - Flow 

Answer 78

Juxtamedullary Nephrons - Flow 

Question 79

Histology of a Renal Corpuscle 

Answer 79

Histology of a Renal Corpuscle 

Question 80

Tubular Reabsorption

Answer 80

Reabsorption is the return of most of the filtered water and many solutes to the bloodstream. * About 99% of filtered water is reabsorbed * Proximal convoluted tubule cells make largest contribution * Solutes are reabsorbed by both active and passive processes

Question 81

Tubular Secretion

Answer 81

Tubular secretion is the transfer of material from blood into tubular fluid. * Secretion of H⁺ helps control blood pH * Secretion helps eliminate substances from the body

Question 82

Reabsorption Routes and Transport Mechanisms 

Answer 82

Reabsorption Routes and Transport Mechanisms 

Question 83

Reabsorption in the Loop of Henle: Chemical composition of tubular fluid is...?

Answer 83

The chemical composition of tubular fluid is quite different from filtrate. Glucose, amino acids and other nutrients have been reabsorbed.

Question 84

Reabsorption in the Loop of Henle: Osmolarity is...?

Answer 84

Osmolarity is still close to that of blood. Reabsorption of water (osmosis) and solutes are balanced.

Question 85

Reabsorption in the Loop of Henle: For the first time, water is...?

Answer 85

For the first time, reabsorption of ***water is NOT automatically coupled to reabsorption of solutes***. There is independent regulation of both volume and osmolarity of body fluids.

Question 86

Reabsorption in the Loop of Henle: Symporters

Answer 86

Na⁺-K⁺-2Cl^- symporters function in Na⁺ and Cl^- reabsorption.

Question 87

Reabsorption in the Loop of Henle: Little or no water is reabsorbed...where?

Answer 87

Little or no water is reabsorbed in the ascending limb. Osmolarity decreases progressively towards the end of the ascending limb.

Question 88

Hormonal Regulation of Tubular Reabsorption and Secretion: Renin-Angiotensin-Aldosterone System (RAAS)

Answer 88

* Renin is released when blood volume and pressure decrease. * Renin converts angiotensinogen to angiotensin I * ACE converts angiotensin I to angiotensin II

Question 89

Hormonal Regulation of Tubular Reabsorption and Secretion: Angiotensin II affects renal physiology by...?

Answer 89

Angiotensin II affects renal physiology by: 1. Decreasing GFR 2. Enhancing reabsorption of Na⁺, Cl^- and water in the PCT 3. Stimulates Aldosterone release by adrenal cortex * Stimulates principal cells in collecting ducts to reabsorb more Na⁺ and Cl^- and secrete more K⁺

Question 90

Summary of Filtration, Reabsorption and Secretion in the Nephron Collecting Duct 

Answer 90

Summary of Filtration, Reabsorption and Secretion in the Nephron Collecting Duct 

Question 91

Evaluation of Kidney Function: Blood Tests

Answer 91

* Blood urea nitrogen (BUN) - measures blood nitrogen that is part of the urea resulting from catabloism and deamination of amino acids. * Plasma creatinine results from catabolism of creatine phosphate in skeletal muscle.

Question 92

Evaluation of Kidney Function: Renal Plasma Clearance

Answer 92

* Volume of blood cleared of a substance per unit time. * High renal plasma clearance indicates efficient exretion of a substancec into urine. * PAH administered intravenously to measure renal plasma flow * More useful in diagnosis of kidney problems than above tests.

Question 93

Ureters, Urinary Bladder and Urethra 

Answer 93

Ureters, Urinary Bladder and Urethra 

Question 94

Body Fluid Compartments 

Answer 94

Body Fluid Compartments 

Question 95

The body can gain water by... 

Answer 95

The body can gain water by: * Ingestion of liquids and moist foods (2300 mL/day) * Metabolic synthesis of water during cellular respiration (200 mL/day) 

Question 96

The body can lose water through... 

Answer 96

The body can lose water through: * Kidneys (1500 mL/day) * Evaporation from skin (600 mL/day) * Exhalation from Lungs (300 mL/day) * Feces (100 mL/day) 

Question 97

Series of Events in Water Intoxication 

Answer 97

Series of Events in Water Intoxication 

Question 98

Intracellular Fluid (ICF) vs. Extracellular Fluid (ECF)

Answer 98

* ECF's most abundant cation is Na⁺, anion is Cl^- * ICF most abundant cation is K⁺, anions are proteins and phosphates (HPO₄^2-) * Na⁺/K⁺ pumps play a major role in keeping K⁺ high inside cells and Na⁺ high outside cells.

Question 99

Sodium (Na⁺)

Answer 99

* Most abundant ion in ECF * 90% of extracellular cations * Plays pivotal role in fluid and electrolyte balance because it accounts for almost half of the osmolarity of ECF * Level in blood is controlled by: * Aldosterone—increases renal absorption * ADH—if sodium is too low, ADH release stops * Atrial Natriuretic Peptide (ANP)—increases renal excretion

Question 100

Bicarbonate (HCO₃^-)

Answer 100

* 2nd most prevalent extracellular anion * Concentration increases in blood passing through systemic capillaries picking up carbon dioxide * Carbon dioxide combines with water to form carbonic acid which dissociates * HCO3- drops in pulmonary capillaries when carbon dioxide is exhaled * Chloride shift helps maintain correct balance of anions in ECF and ICF * Kidneys are main regulators of blood HCO3- * Can form and release HCO3- when blood level is low or excrete excess to the the urine if blood level is high.

Question 101

Calcium (Ca2+)

Answer 101

**Most abundant mineral in body:** * 98% of calcium in adults is in skeleton and teeth * In body fluids, main an extracellular cation * Plays important roles in blood clotting, neurotransmitter release, muscle tone, and excitability of nervous and muscle tissue. **Concentration is regulated by parathyroid hormone:** * Stimulates osteoclasts to release calcium from bone—resorption * Also enhances reabsorption from glomerular filtrate * Increases production of calcitrol to increase absorption from GI tract

Question 102

Acid-Base Balance

Answer 102

* Keeping H+ concentration (pH) of body fluids at an appropriate level is a major homeostatic challenge. * 3D shape of proteins sensitive to pH * Diets with large amounts of proteins produce more acids than bases, which acidifies blood * Several mechanisms help maintain pH of arterial blood between 7.35 and 7.45 1. Buffer systems 2. Exhalation of CO2 3. Kidney excretion of H+

Question 103

Acid-Base Imbalances

Answer 103

The normal pH range of arterial blood is between 7.35 and 7.45 * ***Acidosis*** = blood pH below 7.35 (acidic) * ***Alkalosis*** = blood pH above 7.45 (basic)

Question 104

What are the major physiological effects of acid-base imbalances?

Answer 104

* **Acidosis**—results in depression of synaptic transmission in CNS * **Alkalosis**—results in overexcitability of CNS and peripheral nerves

Question 105

Respiratory Acidosis

Answer 105

Respiratory Acidosis: * Abnormally high PCO2 in systemic arterial blood * Cause is inadequate exhalation of CO2 * Any condition that decreases movement of CO2 out—emphysema, pulmonary edema, airway obstruction * Kidneys can help raise blood pH * Goal is to increase exhalation of CO2 - ventilation therapy

Question 106

Respiratory Alkalosis

Answer 106

Respiratory Alkalosis: * Abnormally low PCO2 in systemic arterial blood * Cause is hyperventilation due to oxygen deficiency from high altitude or pulmonary disease, stroke, or severe anxiety. * Renal compensation can help. * One simple treatment: breathe into a paper bag for a short time

Question 107

Metabolic Acidosis

Answer 107

Metabolic Acidosis: * Abnormally low HCO3- in systemic arterial blood * Loss of HCO3- from severe diarrhea or renal dysfunction * Accumulation of an acid other than carbonic acid—ketosis * Failure of kidneys to excrete H+ from metabolism of dietary proteins * Hyperventilation can help * Administer IV sodium bicarbonate and correct cause of acidosis

Question 108

Metabolic Alkalosis

Answer 108

Metabolic Alkalosis: * Abnormally high HCO3- in systemic arterial blood * Nonrespiratory loss of acid - vomiting of acidic stomach contents, gastric suctioning * Excessive intake of alkaline drugs (antacids) * Use of certain diuretics * Severe dehydration * Hypoventilation can help * Give fluid solutions to correct Cl-, K+