Chapter 35 Section 1

2. Chapter 35 Section 1 • Peristalsis • Pepsin • Bile • Gallbladder • Villus

3. Chapter 35 Section 2 Vocabulary • Mineral • Vitamin • Calorie

4. Chapter 35 Section 3 Vocabulary • Endocrine glands • Pituitary gland • Negative feedback system • Adrenal glands • Thyroid gland

5. Happy Valentine’s Day

6. Digestive/Endocrine RQ! • Where does chemical digestion begin? • What enzyme does this there? • Which chemical substance breaks down fats? • Which organ is crucial for both digestive and endocrine functions? • Which part of the brain connects the nervous and endocrine systems?

7. 1. What are the functions of the digestive system? • To disassemble food into component molecules to be used for energy • Food is ingested and moves through tract • It is broken down mechanically and chemically • The system absorbs the molecules it can use • The system eliminates the undigested materials 

8. 2. The Role of the Mouth • The first step to digestion • Chewing is a form of mechanical digestion • Saliva contains “amylase” which is the first chemical digestion to occur • The food is swallowed and enters the esophagus that connects to the stomach • Smooth muscles move food along through “peristalsis” • The epiglottis covers your trachea when you swallow so food doesn’t get into your lungs 

10. 3. The Stomach • Stomach: a muscular, pouch-like enlargement of the digestive tract • Both physical and chemical digestion • 3 layers of involuntary muscles contract and break down food • Food mixes with gastric juice which contains pepsin and hydrochloric acid • Food remains here for 2 – 4 hours 

12. 4. The Small Intestine • Nearly 6 meters long and 2.5 cm diameter • Duodenum  the first 25cm - pancreas: secretes mixture that digests carbohydrates, proteins, and fats - liver: secretes bile which breaks down fats - gall bladder: stores bile • Food stays here 3 – 5 hours • “villi” help absorb the nutrients from the food and are the link between the digestive & circulatory systems 

14. 5. The Large Intestine • Undigestable material gets here • AKA colon • 1.5 meters long, 6.5cm diameter • Functions in: - water absorption & vitamin synthesis - elimination of wastes: about 24 to 33 hours after food was eaten 

16. Random facts… **Your stomach cells secrete hydrochloric acid, a corrosive compound used to treat metals in the industrial world. It can pickle steel, but the mucous lining in the stomach wall keeps this poisonous liquid safely in the digestive system. **The body's longest internal organ is the small intestine at an average length of 20 feet

18. 6. Vital Nutrients • Carbohydrates  starches and sugars - broken down into simple sugars • Fats  used for energy, insulation, to make hormones - broken down into glycerol & absorbed • Proteins  used for enzymes, antibodies, hormones, blood clotting, muscles - broken down into amino acids & absorbed • Minerals  inorganic substance • Vitamins  organic nutrients (fat & water soluble) • Water  body loses 2.5L each day 

19. 7. Calories & Metabolism • Calorie  the amount of heat required to raise the temperature of 1mL of water by 1’Celsius • Carbohydrates and proteins: 4 calories per gram • Fats: 9 calories per gram • In general males need more than females • Teenagers need more than adults • Metabolic rate is determined by body mass, age, sex, and physical activity 

21. 8. Describe what the “endocrine system” is and what it controls. • Consists of a series of glands that release chemicals directly into the bloodstream • Produces gradual changes • Chemicals are called “hormones” • These are released from the glands and travel to target tissues where they bind to the receptors on the cells • Ex: - human growth hormone (hGH) - blood glucose levels - blood calcium levels 

22. 9. Which portions of your brain are involved in endocrine control? • Action is controlled by the pituitary gland, which is the master endocrine gland, which in turn is controlled by the hypothalamus 

23. 10. What is a negative feedback system? Why is it important? • Negative feedback system  a self-regulating system such as the endocrine system • Acts like a thermostat in your home - maintains a certain temperature - if temperature drops too low or goes too high, the system switches on to correct • Ex: blood water levels detected by the hypothalamus 

25. 11. How is water level controlled in your body? • Water levels drop.. • Hypothalamus senses this and tells the pituitary gland to release ADH (antidiuretic hormone) • ADH tells the kidneys to keep more water and lose less in urine • Water levels stabilize… • Hypothalamus stops stimulating the release of ADH 

27. 12. What controls your blood sugar levels? • Normal blood sugar is 80 – 120 mg/dL • When blood sugar is HIGH… • The pancreas releases insulin, which tells the liver & muscles to take in the glucose • When blood sugar is LOW… • The pancreas releases glucagon, which tells the liver to release the stored glycogen into the blood 

29. 13. What two main types of hormones are there? • There are 2 types of hormones 1. Steroid: freely enter cells, activates the synthesis of certain proteins 2. Amino Acid: open channels in the plasma membrane and alter the behavior of molecules inside the cell 

31. 14. Adrenal Glands and Stress • Play an important role in preparing the body for stressful situations • Located on top of the kidneys • Secrete steroid hormones that increase blood glucose, raise blood pressure, increase heart rate and rate of respiration • Causes the “adrenaline rush” before a stressful situation 

33. 15. Thyroid and Parathyroid Hormones • The thyroid gland regulates metabolism, growth and development through “thyroxine” • Regulate blood calcium levels through a negative feedback system - thyroid makes calcitonin which increases calcium uptake in bones - parathyroid makes PTH which causes the release of calcium from the bones • Calcium is needed for blood clotting, forming bones and teeth, producing normal nerve and muscle function 