Lecture 3

Question 1

way of the blood

Answer 1

1. Blood leaves the right side of the heart by way of the pulmonary artery
   
   2. Blood loses CO2 and picks up O2 in the lungs and return to the left side of the heart by way of the pulmonary vein
   3. Blood leaves the left side of the heart by way of the aorta, the main artery that launches blood on its cours through the body
   4. Blood may leaves the aorta to go to the upper body and head or to the lower body
   5. Blood may go to the digestive tract and then the liver or go to the pelvis, kidneys, legs
   6. Blood returns to the right side of the heart
   7. Lymphs from most of the bodys organs, including the digestive system, enters the bloodstream near the heart

Question 2

general roles of lungs, kidney and liver

Answer 2

• Lungs: exchange oxygen (which enters the blood to be delivered in all cells) and CO2 (which leave the blood to be exhale)
  
  • Digestive system: supply the nutrients
  • Kidney: filter wastes other than CO2 out of the blood to be exctreted in the urine
  • Liver: has many jobs to do in preparing the absorbed nutrients for use in the body. **it is the most metabolically active organ. Also, has a role to defend the body by detoxifying substances that might cause harms and preparing waste products for exctretion

Question 3

lymphatic system + lymph

Answer 3

• Lymphatic system: provides a one way route for fluid from the tissues space to enter the blood. So it is a loosely organized system of vessels and ducts that convey fluids toward the heart. The GI part of the lymphatic system carries the products of fat digestion into the bloodstream.
  
  • Lymph: fluid that circulates between the cells and collects into tiny vessels (move when the muscles contract). Lympf fro the GI tract transports fat and fat soluble vitamins to the bloodstream via lymphatic vessels
  • The lymph will be collected to the THORACIC DUCT behind the heart which is the main lymphatic vessel that collects lymph and drains into the left subclavian vein (the vein that provide the lymphatic system to the vascular system)
  • ** so the nutrients from the GI will enter the bloodstream with one exception: they bypass the liver at first

Question 4

all the way from ingestion to elimination

Answer 4

1. MOUTH: chews and mixed food with saliva ** after the food has been chewed and swallowed, it is called BOLUS
   
   2. PHARYNX: directs food from mouth to esophagus (shared by both digestive and respiratory system)
   3. EPIGLOTTIS: protect airway during swallowing (closes off the airway to prevent choking)
   4. SALIVARY GLANDS: secrete saliva (contain starch-digesting enzymes)
   5. TRACHEA: allows air to pass to an from lungs
   6. ESOPHAGUS: passes food from mouth to the stomach
   7. ESOPHAGEAL SPHINCTER: allow passage from mouth to esophagus and from esophagus to stomach; prevent backflow from stomach to esophagus and from esophagus to mouth
   8. DIAPHRAGM: separates the abdoment fromthe cavity
   9. STOMACH: adds acids, enzymes and and fluids; churns, mixes, and grinds food to a liquid mass. SO it keeps the bolus for a while and then, the food will be called CHYME
   10. PYLORIC SPHINCTER: allows passage from stomach to small intestine; prevents backflow
   11. LIVER: manufacture bile salts, detergent-like substances, to help digest fats
   12. GALLBLADDER: stores bile until dietary fat is present in the duodenum
   13. BILE DUCTS: conducts bile from the gallbladder to the small intestine
   14. SMALL INTESTINE (3 parts: duodenum, jejenum, ileum): secretes enzymes that digest all energy-yielding nutrients to their basic building blocks; cells of wall absorb nutrients into blood and lymph ** fluid is dropped in the small intestine by pancreas and gallblader
   15. ILEOCECAL VALVE (sphincter): allows passage from small to large intestine; prevents backflow
   16. PANCREAS: manufactures enzyme sthat are delivered to the lumen (the space within a vessel) of the small intestine to digest all energy-yielding nutrients and release bicarbonate to neutralize acid chyme that enters the small intestine
   17. PANCREATIC DUCT: conduct pancreatic juice from the pancreas to the small intestine
   18. APPENDIX: store lymphs cells (a blind sac where the intestinal contents that slip into the opening (from the small to the large intestinal) will slipped through
   19. LARGE INTESTINE: reabsorbs water and minerals; passes waste (fibre, bacteria, and unabsorbed nutrients) along with water to the rectum
   20. RECTUM: stores waste prior to elimination
   21. ANUS: holds rectum closed; open to allow elimination of waste

Question 5

3 sphincters

Answer 5

All the sphincter:

1. Esophageal sphincter (mouth to esophagus and esophagus to stomach)
2. Pyloric sphincter: from stomach to small intestine
3. Ileocecal valve (spincter): from small intestine to large intestine 4. The tightness of the rectal muscle acts as kind of safety device: together with the 2 sphincters of anusl it prevents continious elimination

Question 6

the muscular stomach

Answer 6

• It has the thickest walls and strongest muscles of all the GI tract organs
  
  • Has longitudinal and circular muscles + a third layer of diagonal muscles that alternaly contract and relaxe
  • • these 3 muscles work together to break apart the bolus and force the chyme downward (where the pyloric sphincter block its way to make sure it stays in the stomach and mixed with gastric juices by the stomach walls and liquefied)

Question 7

4 functions of the stomach

Answer 7

1. Storage of ingested food for slow release to small intestine
   
   2. Mechanical breakdown of ingested food to peristalsis to chye
   3. Gastrin secretion:
      - Increases peristalsis
      - HCl secretion to activate pepsinogen to pepsin (to denature proteins and begin their digestion)
      - Production of INTRINSIC FACTOR, a glycoprotein

Question 8

cardiac output and peripheral resistance

Answer 8

CARDIAC OUTPUT: volume of blood pumped by the heart within a specific period of time

PERIPHERAL RESISTANCE: refers to the resistance to pumped blood by the small arterial branches (arterioles) that carry blood to tissues

Question 9

non-modifiable and modifiable risk factors of atherosclerosis

Answer 9

Non-modifiable risk factors:

- Age, sex, and family history
1. Men higher risk than women
2. Men older than 45 years old
3. Women older than 55 years of age
4. Immediate family of premature heart disease

Modifiable ones:

1. Smoking
2. Stress
3. Sedentary behaviour
4. Atherogenic diet 
- High energy (calories)
- High saturated fat
- High alcohol
- Low fibre/high glycemic index
- Low vit/minerals
5. Obesity/visceral
6. Hypertension
7. High LDL/HDL
8. High triglycerides
9. High homocysteine
10. Diabetes
11. Chronic inflammation

Question 10

metabolic syndrome

Answer 10

1. Abdominal obesity
   
   • Men: waist circumference more than 40 inches
   • Women: more than 35 inches
   2. Triglycerides: more than 150mg/dL
   3. HDL
      - Less than 40mg/dL in men
      - Less than 50mg/dL in women
   4. Blood pressure: more or equal to 130/85mm Hg
   5. Fasting glucose: more or equal to 100mg/dL

Question 11

5 organs that secrete substances in the digestive system

Answer 11

5 organs thats secrete substances:

1. Salivary glands (saliva is composed of water, salts, mucus and enzymes that initiate the digestion of carbohydrates)
2. Stomach (gastric juice which contain different enzymes such as pepsin and gastrin and HCl)
3. Pancreas (pancreatic juice going to the duodenum, also contain bicarbonate to neutralize the acidic pH of the stomach)
4. Liver (via the gallbladder) (bile goes through the duodenum and acts as an emulsifier)
5. Small intestine (intestinal juice that digest carbohydrates/lipids/proteins, mucus protect the intestinal walls)

Question 12

role of mesentery

Answer 12

The mesentery is a contiguous set of tissues that attaches the intestines to the posterior abdominal wall in humans and is formed by the double fold of peritoneum. It helps in storing fat and allowing blood vessels, lymphatics, and nerves to supply the intestines, among other functions

Question 13

vitamin produces by colon’s bacteria

Answer 13

Vitamins produce:

- Biotin
- Folate
- Pantothenoic acid
- Riboflavin
- Thiamin
- B6
- B12
- K

Question 14

pH bile, saliva, gastric juice, pancreati juice

Answer 14

Bile: 8.5
Pancreatic juice: 8
Saliva: 6.5
Gastric juice: 2

Question 15

functions of the colon

Answer 15

Order of the segments:

1. Ascending colon
2. Tranverse colon
3. Descending colon
4. Sigmoid colon
5. Rectum 
6. anus

Functions:

1. Reabsorption of water and electrolytes
2. Compaction of intestinal contents into feces
3. Absorption of important vitamins produced by bacteria
4. Storage of fecal material prior to defaction

Question 16

iters secrete and absorb along the GI tract

Answer 16

Dietary input: 2000ml
Digestive secretions:
	• Saliva: 1500ml
	• Gastric secretion: 1500ml
	• Liver (bile): 1000ml
	• Pancreas (pancreatic juice): 1000ml
	• Intestinal secretions: 2000ml
Water reabsorption: 
	• Small intestine reabsorbs: 7800ml
	• Colon reabsorbe: 1250ml

• Colonic muscous secretions: 200ml

Final: 150ml lost in feces