Real Internal systems

Macronutrients - Need A Lot

Carbohydrates:

• Found in-bread, pasta, rice, fruit, vegetables

• Function/importance: energy source (glucose), structure (cellulose)

• What molecules make up: monosaccharides (sugar), dissacharides (2 monossacharides), poylsaccharides (starch from plants, or glcogen from animals), cellulose (fibre, can’t digest, plant cell wall)

Proteins:

• Found in-meat, fish, eggs, tofu, nuts, dairy

• Function/importance: structural component of cells, other (hemoglobin, keratin), enzymes

• Made up of: monomers = amino acids

Lipids/Fats:

• Found in: Meat, dairy, oil, nuts

• Function/importance: long term energy storage (triglycerides), cushioning, protection, vitamin absorption, make cell membranes (phospholipids), make hormones (steroids), waterproof coatings on plants and animals (wax)

• Made up of:

  • Saturated: solids, lots of hydrogen, single hydrogen

  • Unsaturated: liquids, lots of multi-bonds

  • 3 carbon sections=glycerol

  • Tails=fatty acids

Micronutrients:

Vitamins:

• organic living molecules

• Found in: Vitamins ABCDEK

Minerals:

• Inorganic molecules

• Found in: Calcium, iron, magnesium

Function: support normal cellular functions, growth and development

Special Nutrients:

Water:

• Found in: liquid, juicy fruit (berries, watermelon, juice)

• Function: body is 55-60% water, necessary for chemical reactions in cells, maintains blood volume, regulates temp

• H2O

The Digestive System

Digestion is the process of converting food substances to a state in which they can be absorbed by the lining of

the digestive tract.

• digestive tract = tube, stretched out would be 6.5-9m in adults (30m)

• peristalsis - wave-like motion caused by the contraction of two muscle layers, pushes food

forward

• sphincters - rings of muscles that mark the beginning and end of the stomach and other

specialized regions, help control the forward movement of food and prevent backflow

A. Steps in Digestion

1. Mechanical digestion: chewing, muscular movements, emulsification

2. Chemical digestion: breakdown of foods by enzymes (produced by glands)

3. Absorption: end-products of digestion are absorbed into the bloodstream

4. Egestion: elimination of unabsorbed waste materials

B. Physical and Chemical Digestion

1. Mouth

a) physical digestion

• incisors-cutting food

• canines-tearing and ripping food

• molars-grinding food

• tongue-moves food around

b) chemical digestion

• saliva - moistens food, enzyme (amylase) begins to break down starch (a carbohydrate), only carbs, anylase-starch-dissarcharydes

2. Stomach (muscular, stretchable sac)

a) physical digestion

• storage and mixing of food

b) chemical digestion

• 2 L of gastric fluids are secreted by lining per day

• HCl-hydrochloric acid breaks down fibrous tissue and kills bacteria

• mucous protects lining from acidity

• pepsin enzyme begins protein digestion

• Stomach = ph2

3. Small Intestine

a) physical digestion

• bile produced in the liver emulsifies fats

• bile is stored in the gallbladder and enters the duodenum

b) chemical digestion

• secretions from the pancreas neutralize acidic chyme-using bicarbonate

• enzymes from pancreas breakdown carbohydrates, fats, proteins

• enzymes enter the duodenum

c) absorption

• villi - finger-like projections that increase surface area for absorption (in

jejunum and ileum)

4. Large Intestine

• concentrates material by absorbing water

• stores feces (mixture of undigested and unabsorbed material, water, bacteria)

• bacteria produce vitamins (b12 and K) which are absorbed

Enzymes

 enzymes are catalysts (agents that speed up reactions)

 they are not used up in reactions, therefore can be used again and again and again and again and again ...

Factors that Influence Enzyme Activity

1. Temperature

Humans digestive enzymes are most active at normal body temperatures (37), approaching 40 enzyme is altered, above 40 enzyme action is stopped protein is denatured)

2. pH

Some enzymes work bestg at neutral ph (amylase in saliva), some enzymes

Chemical Digestion of Carbohydrates

 begins in mouth, amylase in saliva breaks down starch into maltose (disaccharide)

 continues in small intestine: pancreatic amylase breaks down remaining polysaccharides

 digestion of disaccharides occurs in small intestine (jejunum) with enzymes produced by cells lining the

intestine

 monosaccharides absorbed by villi and enter bloodstream for transport to body cells

Carbohydrate Digesting Enzymes of the Jejunum

Substrate Enzyme Product

maltose Maltase 2 glucose

lactose Lactose glucose + galactose

sucrose sucrase glucose + fructose

starch amylase maltose

Mechanical and Chemical Digestion of Fats

 mechanical digestion of fats (in mouth and stomach) converts pieces of fat into smaller fat globules

 in bile from liver makes fat globules smaller and spreads them through the chyme

 in duodenum, lipase (enzyme from pancreas) splits fat into glycerol and fatty acids

 products are absorbed by villi

Chemical Digestion of Proteins

 protein digesting enzymes are first released as inactive enzymes so that

they don't digest the enzyme-secreting cells themselves

 enzyme precursors only become active when they reach the digestive tract

 in stomach, pepsin breaks protein molecules into long-chain amino acids (pepsin is produced

by the stomach lining cells)

 in small intestine, proteases (from the pancreas) break proteins into amino acids

 single amino acids are absorbed by villi

The Respiratory System

 The respiratory system functions to bring oxygen into the body and removes co2

Composition of Air

Gas N2 O2 Ar CO2

Inhaled 78% 21% ~1% 0.03%

Exhaled 78% 16% ~1% 5%

1. Breathing

Inhalation

 diaphragm contracts (it flattens and moves downwards)

 intercostal muscles contract to move rib cage up and out

 thoracic cavity enlarges

 pressure in lungs decreases

 air rushes in

Exhalation

 diaphragm relaxes and moves upwards

 intercostal muscles relax to move rib cage down and in

 volume of thoracic cavity decreases

 pressure in lungs increases

 air is forced out

Pathway Air Follows:

Inhalation: nasal cavity or mouth, pharynx, larynx and vocal chords, trachea, bronchi, bronchioles, alveoli

Exhalation: alveoli, bronchioles, bronchi, trachea, larynx and vocal chords, pharynx, nasal cavity or mouth

2. Air Processing

Blood Vessels: warm air to body temp

Cilia: small hairs ining nasal cavity and airways, sweeps debris and dirty mucous up trachea for disposal by coughing swallowing, spitting

Mucous: coats cillia and lung tissue, traps dust and bacteria, allows gases to dissolve so they can move through membranes

3. Gas Exchange

External Respiration

 oxygen diffuses from alveoli into blood

 oxygen binds to hemoglobin and is carried by red blood cells

 carbon dioxide diffuses from blood into alveoli

Internal Respiration

 oxygen diffuses out of blood into extra-cellular fluid and then into cells

 carbon dioxide diffuses out of cells into extra-cellular fluid and then into blood

 carbon dioxide is carried in plasma as disolved gas

4. Cellular Respiration

 occurs in mitochondria

 breakdown of glucose to produce ATP (cellular energy)

 requires large amounts of oxygen

 produces carbon dioxide and water waste

5. Regulation of Breathing

6. Lung Volumes

 Tidal Volume – the amount of air the passes in and out of the lungs with each breath

 Total Lung Capacity – the maximum volume of air that can be held in the lungs

• At rest, the tidal volume is only a small fraction of the total lung capacity

 After the normal tidal volume is exhaled, more air can be forcefully exhaled – Expiratory Reserve Volume

 During a deep breath, an extra volume of air can be inhaled – Inspiratory Reserve Volume

 The maximum amount of air that can be moved into and out of the respiratory system is called the Vital

Capacity

• This value is always 1-1.5L less than the total lung capacity....WHY?

 The 1-1.5 L of air that always remains in the lungs is called the Residual Volume

Worksheet: Comparisons of Metabolic Rates of Animals Date:

VO2 max, or maximal oxygen consumption, refers to the maximum amount of oxygen that an individual can utilize

during intense exercise. This measurement is generally considered the best indicator of cardiovascular fitness and

aerobic endurance. The more oxygen a person can use during high level exercise, the more energy a person can

produce. VO2 max is useful for determining cardiorespiratory fitness because the muscles need oxygen for

prolonged aerobic exercise, and the heart must pump adequate amounts of blood through the circulation to meet

the demands of aerobic exercise.

VO2 max is measured in a laboratory by putting a face mask on the subject and directly measuring the volume and

gas concentrations of inspired and expired air. The test involves either exercising on a treadmill or a bike at an

intensity that increases every few minutes until exhaustion, and is designed to achieve a maximal effort. Because

we are unable to replicate the test in a classroom, you will calculate your metabolic rate with a procedure

designed to simulate the measurement of VO2 max.

Procedures

1. Measure your tidal volume (L) using the breathing volume bags provided.

2. Calculate your mass in kg. (1 kg = 2.2 lbs)

3. Measure your average breathing rate per minute (at rest).

4. Given the following information:

Metabolic rate is measured as the volume of oxygen inhaled per unit body weight per unit time (mL O2/kg•hr). Note: Oxygen makes up 21% of air by volume.

1. Compare the metabolic rate of the crocodile and the lion. Explain why the crocodile has a lower metabolic rate than the lion.

Croc is cold blooded so it needs less energy, wheras the lion is warm blooded.

2. Compare the metabolic rate of the rhinocerous and the gerbil. Explain why the gerbil has a higher metabolic rate than the rhinocerous.

Rhino is insulated the gerbil is almost entirely surface area

3. Compare the metabolic rate of the Florida dolphin and Greenland orca. Explain why the Greenland orca has higher metabolic rate than the Florida dolphin.

Florida waters are warmer than Greenland’s

4. Compare the volume of oxygen inhaled per kilogram hour by the human to the other animals. How do you account for these differences?

Humans have clothes heating and don’t need to regulate ourselves

The Circulatory System

Purpose of the circulatory system:

• To circulate necessary materials to all cells (e.g. oxygen, nutrients, hormones)

• To remove waste products of cell metabolism

• To equalize temperature in various parts of the body

Erythrocytes: Red blood cell, carries oxygen to all cells with hemoglobin, formed in bone marrow 2.5 million a second, bi concave disks no nucleus, 7 micrometers, 4 to 6 billion per cm3, 90-120 days killed by liver

Leukocytes: White blood cell, fights infections, formed in bone marrow 120,00 a second, some stored in lymphnodes, have nucleus some have granuoles in cytoplasm 10-15 micrometers, 5 to 9 millin per cm 3, live hors to years

Thrombocytes: Plateletes, clot blood, formed in bone marrow 5 million a second, fragments of cells, 1-2 micrometers, 250 million per cm 3, live 7 to days

Blood Vessels

1. Arteries and arterioles:

• carry blood away from the heart

• walls contain a thick muscle layer that help control the flow of blood and enables them to withstand high pressures

2. Veins and venules:

• carry blood to the heart

• walls have thinner muscle layer and can stretch more easily; cannot carry blood at high pressures

• contain sets of one way valves to prevent the backflow of blood

3. Capillaries:

• capillary beds connect arterioles and venules

• capillaries have thin, permeable walls (one cell thick)

• gas exchange (diffusion of oxygen into cells and CO2 out) occurs at capillaries

Circulation

• Pulmonary circulation: supply of blood to the lungs

• Cardiac circulation: supply of blood to the heart

• Systemic circulation: supply of blood to rest of the body

The Heart

 is a muscle that supplies the pressure to move the blood through the arteries

 is made of cardiac muscle tissue

 is covered with a sac of epithelial and fibrous tissue called the pericardium (the pericardium contains liquid

which reduces friction as the heart beats)

A. Structure of the heart

 the heart consists of two pumps, separated by a muscular wall called the septum (the septum prevents the

mixing of blood from the two sides)

 the two pumps in the heart each have two chambers; the atrium (on top), and the ventricle (on the bottom)

 an atrioventricular valve controls the flow of blood between the atrium and the ventricle

B. Heart Beats

 the pacemaker (sinoatrial (SA)node) is a group of nerve fibers in the right atrium that maintain the

beating of the heart

 one heart beat = one cardiac cycle

 each cardiac cycle consists of a systole (a contraction of the heart) and a diastole (a relaxation of the heart)

 the sounds you hear when your heart beats are the sounds of valves in your heart closing (first the

atrioventricular valves (bicuspid and tricuspid), then the semi-lunar valves)

Blood Pressure

Force of heart pushing blood around force of blood pushing against arteries. Blood thickens lots of salt keeps more water stress constricts key bessels, damage, narrowing of blood vessels also happens with age.

Left ventricle-aortic valve-aorta-arteries-capillaries-veins-venca cava-right atrium-tricuspid valve-right ventricle-pulmonary semilunar valve-lung-pulmonary vein-left atrium-bicuspid-left ventricle

Acid Reflux: stomach acid goes back up esophagous burning it, heartburn or GERD can be caused. Sphincter at bottom of esophagous opens, Esophagitis-ulcers imflammation, risks of esophageal cancer, esophagous narrows.

Peptic ulcers: sores in stomach or small intestiens, paintful bloating, vomitting. Lining in stomach or duodernum gess eroded exposing senstive tissue to peptin. Sever bleeding in stomach or intestine requiring transufsion, block stomach leading to backup and vomitting, hemorrhage gastric outlet.

VOmitting: food comes out of mouth painfully, harmful substances are removed. Immune response/nervous system, muslces contract, mucous protects lungs, pressue in stomach increases, brain prepares. Choke on it, dehydration

Diarrrhea: lots of loose watery pooo, expelled quickly. triggered intestinal muscles contract quickly no water absorption. Dehydration

Colonoscopy: see iside of rectum and colon, colonoscope (flexicble lighted tube). Used to screen for cancer cause of abdominal pain, rectal bleeding.

Capsule Endoscopy: nonenvasive, visualive small intestine, swallow tiny pill camera, check for bleeding polyps tumors celicac.

Proton Pump Inhibitoirs: Medication that reduces stomach acid production. Inhibit production of stomach acid. Treats acid reflux heart burn.

Magnetic sphincter: Surgical device placed on esophageal sphincter to allow food to go in but keeps stomach acid down. (ring shaped magnets). controls reflux

Asthma: Muslces tighten constricting airway, lots of mucus. Chronic imflammatory condition, immune system overreacts and imfalmes airway. Reduced lung function, lots of attacks, inability to excersize, more infections, possible pregnancy loss.

Emphysema: Alevoli are damaged causing them to rupture. Alveoli are damaged fewer air sacs harder to get oxygen, air trapped, caused by irritants, smoking. Increased risk of: respiratory infections, heart problems, high blood pressure, increased risk of lung cancer, mental health issues.

Popcorn Lung: Bronchioles get imflamed damaged and scar abstructs airflow makes breathing dificulties. Lung disease from chemicals, vaping and popcorn factories. Difficulty breathing, lung damage, respiratory failure.

Asbestosis: Asbestos fibres irritate lung leading to scarrring and makes lungs stiff. Inhaling asbestos in the lungs leads to scarring. Increased lung cancer risk, mesothelioma, chest abdomen cancer.

Pulse Oximetry: Used to measure the saturation of oxygen in your blood. Device clips to your finger and a light that shines through finger checks O2. Used fo rindividuals with heart or lung problems.

Spirometry: Common breathing test that checks how much air you can blow out and how fast. Help diagnose conditions like COPD and Asthma. You wear a nose clip and breath into the special mouthpiece.

Artificial Surfactant: Substance used to treat respiratory distress syndrome. You don’t have many alveoli helps mimic alveoli to help premies breath.

Artifiical Transplant: An engineered device or tissue that acts as a natural organ in your body. Used to replace, duplicate other non functioning organs. Helps with donor shortage.

Sickle cell anemia: Heamoglobin is mishapen in sickle shape instead of round, leading to blockages in blood vessels. Genetic mutation. Chronic pain, stroke, increased infection risk, anemia, organ damage.

Arteriosclerosis: blood vessels that carry oxygen and nutrients from heart become thick and stiff. High cholesterol, high blood pressue, diabetes, genetics. Heart attack, stroke, blood clot.

Angina Pectoris: heart muscle doesnt get enough oxygen and blood. COrnonary artery disease, plaque blocks blood vessels, smoking, diabetes, age, obesity. Heart attack, stroke, cardiac arrest.

Cerebrovascular Accident: Brain blood flow is disrupted no oxygen or nutrients damage or death of brain cells. Stroke/artery to brain is blocked. Brain damage-disabiligy, paralysis, memory loss, vision loss, emotion changes.

Electrocardiogram (ECG): Measures electrical activity of the heart. Used to diagnose heart problems or assess a hearts health before surgery.

Coronary Angiogram: X-ray test used to see your coronary arteries using a special dye. Used to detect blockage or narrow arteries. Helps diagnose coronary arteries.

Heart Valve Replacement: Remove a damaged heart valve and replace it with a new one. Used to restore proper blood flow fix narrowing or leaking.

Artificial Heart: Mechanical device designed to replace a failing heart. Used to temporarily replace a patient who is wating for a heart transplant or is the solution for people who aren’t candidates for a heart transplant.

Part I – Presentation

1. Definition of a hormone. Does gastrin fit the description of a hormone?

2. Hormone definition: A hormone is a chemical messenger secreted by endocrine glands that travels through the bloodstream to affect the function of distant target cells or organs.

   • Does gastrin fit the description of a hormone? Yes, gastrin is a hormone. It is produced by G cells in the stomach and duodenum, and it travels through the bloodstream to the parietal cells in the stomach, where it stimulates acid secretion. Its action is distant and chemical, fitting the definition of a hormone.

3. What are the functions of gastrin?

4. Gastrin primarily stimulates the secretion of gastric acid by parietal cells in the stomach. It also promotes the growth of the gastric mucosa and increases gastric motility. Additionally, gastrin helps regulate the process of digestion by promoting the breakdown of food and absorption of nutrients.

5. In healthy individuals, which cells usually secrete gastrin? Where are those cells located?

6. Gastrin is secreted by G cells. These cells are located mainly in the antrum of the stomach and the duodenum.

7. Which cells secrete acid? What is the role of acid in the stomach?

8. Acid is secreted by parietal cells in the stomach lining. The role of stomach acid (HCl) is to create an acidic environment for the activation of digestive enzymes (like pepsin), denature proteins, kill harmful microorganisms, and aid in the absorption of certain nutrients, like vitamin B12.

9. What other important substance do the cells in Question 4 release? Describe the function of that substance.

10. In addition to acid, parietal cells also secrete intrinsic factor. Intrinsic factor is essential for the absorption of vitamin B12 in the small intestine, specifically in the ileum. Without intrinsic factor, B12 absorption would be impaired, leading to deficiencies.

11. Gastrin causes proliferation of the cells in Question 4, which may account for the increased gastric folds noted on endoscopy. How might this proliferation affect the symptoms and the course of ZES?

12. The proliferation of parietal cells in ZES can lead to an increased secretion of gastric acid, contributing to more severe ulcers and damage to the stomach lining. The growth of acid-producing cells may also lead to the formation of excessive gastric folds, which can further exacerbate symptoms like abdominal pain, indigestion, and nausea.

13. Explain how the release of gastrin is usually regulated. Why doesn’t this regulation work for Mr. Akin?

14. Normally, gastrin release is tightly regulated. It is stimulated by the presence of food in the stomach and inhibited by a low pH (acidic environment) in the stomach. However, in Zollinger-Ellison syndrome (ZES), the gastrinoma (a tumor) continuously secretes high levels of gastrin, bypassing the normal regulatory mechanisms. This results in unregulated acid secretion, leading to ulcers and other gastrointestinal problems.

15. One of the main functions of gastrin is to regulate acid secretion in the stomach. How is acid generated and released in the stomach?

16. Acid is generated by parietal cells through the H+/K+ ATPase pump, also known as the proton pump. This pump exchanges potassium ions (K+) for hydrogen ions (H+) across the parietal cell membrane, into the stomach lumen. The hydrogen ions combine with chloride ions to form hydrochloric acid (HCl), which is secreted into the stomach.

Part II – Diagnosis

1. Why should the gastrin level be measured during fasting?

2. Measuring fasting gastrin levels provides a baseline level of gastrin secretion when the stomach is not stimulated by food. This helps accurately assess whether the gastrin levels are abnormally high, which is characteristic of ZES. After food intake, gastrin secretion naturally increases, making it harder to interpret levels for diagnosing disorders like ZES.

3. What abnormalities are revealed in Mr. Akin’s blood results? Are these consistent with the diagnosis of ZES?

• Mr. Akin's fasting gastrin level is 1650 pg/mL, which is significantly higher than the normal range of 150 pg/mLand well above the threshold of 1000 pg/mL that is indicative of ZES. These results are consistent with the diagnosis of Zollinger-Ellison syndrome, as they suggest excessive gastrin secretion, likely from a gastrinoma.

Part III – Additional Evidence

1. What are the functions of secretin?

• Secretin is a hormone produced by the S cells in the duodenum. It primarily stimulates the pancreas to release bicarbonate, which neutralizes stomach acid in the small intestine. Secretin also inhibits gastric acid secretion and motility, helping to regulate the digestive process.

1. Compare how secretin works in a healthy individual and how it works in someone with ZES.

• In healthy individuals, secretin inhibits gastrin release and gastric acid secretion by acting on the parietal cells. However, in individuals with ZES, secretin paradoxically stimulates gastrinoma cells, causing them to release even more gastrin. This results in increased acid production, contrary to the normal inhibitory role of secretin.

1. Hypothesize how the paradoxical action of secretin in ZES might play a role in the pathophysiology of the disease.

• In ZES, the gastrinoma cells are unresponsive to the usual regulatory controls, including secretin. Instead of inhibiting gastrin release, secretin stimulates the tumor cells, which increases the production of gastrin and exacerbates acid secretion. This leads to more severe ulcers, gastrointestinal discomfort, and the potential for other complications like gastrointestinal bleeding or perforation.

Part IV – Treatment

1. Hypothesize how you think a proton-pump inhibitor may work to control acid levels in the gastrointestinal tract.

• Proton-pump inhibitors (PPIs) work by inhibiting the H+/K+ ATPase pump in parietal cells, which is responsible for secreting hydrogen ions (acid) into the stomach. By blocking this pump, PPIs reduce the amount of gastric acid produced, helping to control acid-related symptoms and promote healing of ulcers.

1. ZES is associated with MEN type 1. Do some research on this disease, including clinical manifestations and epidemiology. Prepare a short presentation discussing your findings.

• Multiple Endocrine Neoplasia Type 1 (MEN 1) is a rare, inherited condition that predisposes individuals to develop tumors in multiple endocrine glands, including the pituitary, parathyroid, and pancreas. These tumors can be benign or malignant. MEN 1 is caused by mutations in the MEN1 gene, which encodes a tumor suppressor protein. Clinical manifestations include hyperparathyroidism, pituitary tumors, and pancreatic tumors such as gastrinomas. The disease follows an autosomal dominant inheritance pattern and has an onset typically in young adulthood. About 20-30% of ZES cases are associated with MEN 1. People with MEN 1 often develop multiple tumors over their lifetime, and the disease requires careful monitoring and management to address the tumors and related complications.