Introduction to Organ Systems and Digestive system

1. Introduction to Organ Systemsand Digestive system

2. The fact that every organism continuously exchanges chemicals and energy with its surroundings indicates that organisms ________. are closed systems have tightly controlled thermoregulation osmoregulate are open systems In a multicellular organism, cellular exchange with the environment can only occur if ________. temperatures are variable homeostasis requires energy expenditure cells have access to a suitable watery environment the body is a closed system

3. Exchanges with the External Environment Every organism is an open system that continuously exchanges chemicals and energywith its surroundings. • Every living cell of an animal’s body must bebathed in a watery solution, partly because substances must be dissolved in water to cross cell membranes. Which animals have it easier? • An animal’s size and shape affect its exchanges with its surrounding environment. Compare the a similar size sponge, jellyfish and fish? in which one can all of their cells exchange directly with the environment?

4. Contact of simple organisms with the environment Mouth Gastrovascular cavity Exchange Exchange Exchange (a) Single cell (b) Two cell layers

5. Exchange with the environment is more complicated for complex, multilayered animals.

6. If the room becomes too warm, the next thing that will occur is ________. the set point decreases the heater is turned off heating stops the room cools This is an example of a _________ Feed back loop Maintaining a constant temperature Is an example of ______________

7. Since the body is an open systemit is sensitive to changes in the surrounding environment But the body needs to maintain constant conditions inside “Homeostasis” What needs to be maintain constant? SOLUTION: Systems function together to maintain homeostasis

8. Organ’s form fits Organ’s function As product of natural selection Structure of a body part (aka anatomy) Corresponds With the task it must perform (aka physiology) How does the anatomy Of the bird bones fit With the physiology?

9. Human organ systems (part 1: skeletal) Metacarpals Carpals Phalanges Radius Ulna Skull Bone Humerus Shoulder girdle Clavicle Scapula Sternum Ribs Cartilage Vertebra Pelvic girdle Skeletal system: supports body and anchors muscles Femur Patella Tibia Fibula Tarsals Metatarsals Phalanges

10. Human organ systems (part 2: circulatory) Circulatory system: transports substances throughout body Heart Blood vessels

11. Human organ systems (part 3: respiratory) Respiratory system: exchanges O2 and CO2 between blood and air Nasal cavity Pharynx Larynx Trachea Bronchus Lung

12. Human organ systems (part 4: muscular) Muscular system: moves the body Skeletal muscles

13. Human organ systems (part 6: urinary) Urinary system: rids body of certain wastes Kidney Ureter Urinary bladder Urethra

14. Human organ systems (part 1: endocrine) Endocrine system: secretes hormones that regulate body Hypothalamus Pituitary gland Parathyroid gland Thyroid gland Adrenal gland Ovary (female) Pancreas Testis (male)

15. Reproductive system: produces gametes and offspring Human organ systems (part 2: reproductive) Seminal vesicles Prostate gland Vas deferens Oviduct Penis Ovary Uterus Urethra Vagina Testis

16. Human organ systems (part 3: integumentary) Integumentary system: protects body Hair Skin Nail

17. Human organ systems (part 4: lymphatic and immune) Lymphatic and immune system: defends against disease Tonsil Thymus Spleen Appendix Lymph nodes Lymphatic vessels

18. Human organ systems(part 5: nervous) Nervous system: processes sensory information and controls responses Brain Sense organ (ear) Spinal cord Nerves

19. Human organ systems (part 5: digestive) Digestive system: breaks down food and absorbs nutrients Mouth Esophagus Liver Stomach Large intestine Small intestine Anus

20. Tissue layers make up organs Small intestine (cut open) Epithelial tissue Connective tissue (containing blood and lymph vessels) Smooth muscle tissue (two layers) Epithelial tissue Connective tissue

21. Source chemical energy That can be extracted by cellular respiration This process requires participation of Digestive, Respiratory and Circulatory Systems What is the purpose of Food? Source of building materials Some need to be consumed already fabricated  essential nutrients 8 amino acids 13 Vitamins 12 Minerals Essential fatty acids

22. Why does food need to be broken down? Lysine is an essential amino acid for animals. If an animal did not consume lysine in its diet, you might expect that the animal ________. was a carnivore would be very healthy could not effectively make many necessary Proteins would make lysine from other amino acids

23. The steps in breaking down food What is the order of the four stages of food processing? ingestion, elimination, digestion, absorption ingestion, absorption, elimination, digestion ingestion, digestion, absorption, elimination digestion, absorption, ingestion, elimination Which lists the major segments of the alimentary canal in the correct order? oral cavity, stomach, esophagus, small intestine, large intestine esophagus, oral cavity, stomach, small intestine, large intestine oral cavity, esophagus, stomach, large intestine, small intestine oral cavity, esophagus, stomach, small intestine, large intestine

24. Chemical digestion: hydrolysis of food molecules Protein Amino acid H2O H OH Enzyme (pepsin) Carbohydrate Sugar H2O OH H Enzyme (amylase) Fat Fatty acid H2O Glycerol OH H H2O OH H H2O H OH Enzyme (lipase)

25. Digestive system consists of an alimentary canal and accessory glands

27. Digestion begins in the ______. stomach pharynx oral cavity esophagus Most mechanical processing of food occurs in the _____. oral cavity and stomach oral cavity and small intestine small intestine and large intestine stomach and small intestine This image shows: The mechanical digestion of a protein the building of a protein by the enzyme pepsin the chemical digestion of a protein the addition of a water molecule to add an amino acid to a protein

28. Mechanical digestion, the process of breaking down large chunks of food into smaller pieces, is important because smaller pieces of food ________. have more surface area for chemical digestion than do larger pieces of food do not taste as good as larger pieces of food are more easily stored in the stomach than are larger pieces of food are easier to excrete than are larger pieces of food Several important enzymes and other secretions aid in digestion as food moves down the alimentary canal, as follows: in the oral cavity, salivary amylase helps break down _____; in the stomach, pepsin helps break down _____; and in the small intestine, bile helps break down _____. fats and oils; proteins; starches starches; fats and oils; proteins proteins; starches; fats and oils starches; proteins; fats and oils Together, the body secretes about 7 liters of water into the alimentary canal each day and reabsorbs 90? Why does the canal need so much water and what organ is ONLY in charge of water absorption?

29. __________ is the uptake of small nutrient molecules by cells lining the digestive tract. absorption elimination digestion ingestion For which function of human digestion is the small intestine most important? ingestion digestion absorption elimination b. and c. • If you were to measure along the human digestive tract, how far along would be a point in the large intestine? • 2 feet • 6 feet • 10 feet • 15 feet • 28 feet

30. Small intestine: example of form fits function Form: Your small intestine is about 4 times your body length Diameter, folds, villi, microvilli

31. Liver is an important organ In addition to digestive functions, the liver plays several other roles: • detoxification of blood; • synthesis of blood proteins; • destruction of old red blood cells • storage of glucose as glycogen, and its release when blood sugar levels drop • production of urea from amino groups and ammonia.

32. Digestive Systems in Animals No digestive system: Sponges why? They have an intracellular digestion

33. Digestive Systems in Animals Gastrovascular cavity: Cnidarians and Flatworms (absent in Tape worm) One opening, two way movement of food How is the gastrovascular cavity of flatworms different from that of the cnidarians?

34. An advantage of a complete digestive system over a gastrovascular cavity is that the complete system _____. allows extensive branching facilitates intracellular digestion allows for specialized regions with specialized functions excludes the need for extracellular digestion

35. Digestive Systems in Animals Digestive tract: two openings, one way movement, advantage? Pharynx: muscular pouch For mechanical digestion Esophagus Crop: moistens and stores food Gizzard: churns food and Usually has grit or gravel Intestine: Earthworm is crescent shape Accessory organs: Digestive glands In vertebrates Pancreas and liver

36. Digestive glands Sea stars: pyloric ceca Grasshopper: gastric ceaca Crayfish: digestive gland

37. Evolutionary adaptations of digestive systems correlate with diet In mouth: Most non-mammalian vertebrates do not have specialized teeth Mammals are so successful because they can take advantage for different diets Insects also modified their mouthparts to tap into different foods

38. Mutualistic Adaptations Gut microbiome: • some intestinal bacteria produce vitamins, such as vitamin K, biotin, and folic acid, that supplement our dietary intake when absorbed into the blood. • Intestinal bacteria also regulate the development of the intestinal epithelium and the function of the innate immune system.

39. Animals cannot produce enzymes to digest cellulose, yet many termite species consume cellulose from plant material as a main part of their diet. How do termites access the nutrients contained in cellulose? Termites have specialized mouthparts to mechanically break down the cellulose. Mutualistic bacteria in the hindgut of the termite digest the cellulose into sugars. The ingested plant material also contains enzymes for cellulose digestion. Cellulose is digested intracellularly in the termite hindgut.

40. The length of digestive system is correlated with diet Herbivores have larger digestive systems because it is harder to digest plants The cecum is particularly large In herbivores because This sac contains bacteria that breakdown cellulose How does human anatomy indicate that our primate ancestors were not strict vegetarians?

41. A bear and not a bear Pandas spend up to 14 hours eating 0.3 lbs food/lb body (6x) Koalas spend about 4.7 h eating 0.05 lbs food/lb body