Animal Systems 1

1. Animal Systems 1

2. Body organization • Unicellular • Multicellular simple • Multicellular complex-rely on folded and branched internal surfaces to facilitate exchange of materials

3. Levels of organization • cells tissues organs systems • Tissues are composed of cells with a common structure and function • Cells are held together with a sticky matrix

4. There are 4 types of tissues:

5. 1. Epithelial-covers outside of body and lines organs and cavities • Cells are tightly joined • Simple or stratified • Shape may be squamous, columnar or cuboidal

6. 2. Connective-binds and supports other tissues • Composed of a few cells in a matrix • Connective tissue is made of 3 kinds of fibers: a. Collagen fibers-collagen is the most abundant animal protein, these fibers are non-elastic and do not tear easily b. Elastic fibers-long threads of elastin protein that provide a rubbery quality c. Reticular fibers-thin and branched, they join connective tissue to adjacent tissue

7. Types of connective tissue: a. Loose b. Adipose c. Fibrous d. Cartilage e. Bone f. blood

8. 3. Muscular-long cells called fibers that are capable of contracting -most abundant tissue in animals -muscle contractions use much of the energy produced in respiration

9. 4. Nervous-senses -sense stimuli -transmits signals -mostly concentrated in the brain

10. Staying warm or cool: • Endothermic-produce heat from inside, includes birds, mammals, some fish and some insects • Body coverings help retain heat (fur, fat layers) • High metabolic rate (80% can go to heat) • Modify behavior (migrate, hibernate) • Panting • Seeking shade • Huddling • Shedding • Thicker fur • Nocturnal

11. Ectothermic-gain heat from external sources, includes most fish, amphibians, reptiles • Body coverings help retain heat-scales • Modify behavior (basking) • Fanning wings • Nocturnal

12. Homeostasis • Maintaining the internal environment • Body temperature • Water-salt balance • Carbon dioxide • Glucose • pH

13. Homeostatic control: Negative feedback • Sensor • Control center

14. Negative feedback-a change causes the control center to counteract any further changes Prevents small changes from becoming too big • Positive feedback-a change causes the control center to increase the response Example-labor

15. Digestive system • Obtaining food • Filter feeders-sift small particles from water (baleen whales) • Fluid feeders-parasites that tap into the vascular system of host • Substrate feeders-live on the material they eat (maggots) • Bulk feeders-bite off chunks or whole organism

16. Essential Nutrients Must be preassembled as the animal cannot make them 1. Amino acids-need 20 to make all proteins, about half are essential. • Protein deficiency is the most common type of malnutrition in humans

17. 2. Fatty acids-deficiencies are rare 3. Vitamins-organic, need very small amounts, 13 are essential • Water soluable-excess excreted in urine • Fat soluable-excess stored and may be toxic (A, D, E, K) 4. Minerals-inorganic, too much may cause toxic side effects

18. Food Processing • Ingestion-eating • Digestion-breaking down food to small molecules • Enzymatic hydrolysis-splitting large molecules • Absorption of small molecules • Elimination of undigested waste

19. Complete digestive system • Consists of two openings-mouth and anus • Long tube with specialized structures

20. Structures of digestion • Mouth-saliva moistens food and makes it slippery, contains the enzyme amylase to break down starch • Teeth make food smaller • Pharynx-throat • Larynx-contains vocal cords

21. Esophagus-muscular tube that carries food to the stomach • Food is pushed down by waves of muscle contractions called peristalsis • No food is digested in the esophagus

22. Stomach, j shaped elastic sac, stores and mixes food with gastric juices • HCl- ph= 2, the acid breaks down the matrix that holds cells together and kills most bacteria • Pepsin-enzyme that breaks down proteins • Sphincters (circular muscles) keep food inside until consistency of thick milkshake

23. The stomach is coated with a mucus lining that protects it from acid • Even so, the stomach lining is constantly eroded and replaces itself every 3 days

24. Accessory organs • Liver-makes bile • Gall bladder-stores bile Pancreas--secretion acts as a pH buffer, bile acts as a detergent (emulsifies fat)

25. Small intestine • 6 meters long • Most of the breakdown and absorption occurs here • Duodenum-first 25 cm, juices from pancreas, liver, gall bladder and intestine are added here

26. Absorption in the small intestine • Has huge surface area (300 m2 or size of tennis court) • Folds with projections called villi • Each villus has microvilli • Inside each villus is a network of capillaries and lymph vessels

27. Large intestine (colon) • 1.5 m long • Cecum is pouch at the beginning where appendix attaches • Recovers water, waste becomes solid • Contains harmless bacteria (some produce vitamins) • Rectum is end portion where waste is stored until elimination

28. Problems Eating disorders • Anorexia-refusing to eat enough to be healthy • Bulimia-overeating and purging • Binge eating-overeating without purging Diabetes • Type I-no insulin is produced by the pancreas • Type 2-insulin resistance (cells do not take up glucose even if insulin is present), associated with obesity High cholesterol leads to cardiovascular disease

29. Circulatory system • Open systems-blood bathes organs directly, no vessels • Closed systems-all blood is contained in vessels

30. Double loop system A. The heart -size of a fist -4 chambered 2 thin walled atria serve as receiving chambers 2 thick walled ventricles serve as pumping chambers -chambers separated by valves to prevent backflow

31. Cardiac cycle-one complete sequence of filling and contracting • Heart rhythm • SA node (pacemaker)-specialized cells that set the rate • Located in wall of right atrium • AV node spreads signal throughout heart • Located in wall between right atrium and right ventricle Produces electrical currents recorded as EKG

32. B. Blood vessels -arteries are 3 layers with thick muscle, extra strength is needed for uneven speed and pressures -veins are also 3 layers but thinner, flow is mainly due to skeletal muscle contractions. valves prevent backflow

33. -capillaries-one cell thick, allows exchange of material between blood and fluid around cells

34. Capillaries in the heart, brain, and kidneys are always filled to capacity. Others may be diverted as needed. For example, after a meal capillaries in digestive tract are full, while exercising capillaries in muscles are full.

35. Blood pressure-created by force of blood pushing against vessel walls • Greater in arteries than veins • Contraction pressure is called systole • Relaxation pressure is called diastole • Healthy: 120 systole 80 diastole

36. C. Blood composition • Plasma-liquid portion of blood, 90% water with dissolved ions, proteins, antibodies, clotting factors, nutrients, waste, hormones, CO2, O2

37. RBC (erythrocytes)-transport oxygen, most numerous of the cells, disk shape helps perform function, lack nuclei, contain hemoglobin • WBC (leukocytes)-fight infection • Platelets-cell fragments, no nuclei, help clot blood

38. Problems 1. Cardiovascular disease-caused by a combination of lifestyle and genetics a. atherosclerosis-deposits of cholesterol thicken and harden artery walls. It narrows the opening and causes platelets to adhere triggering a clot

39. b. hypertension (high blood pressure)-promotes atherosclerosis and increases risk of heart attack and stroke c. heart attack-death of part of heart due to blockage and loss of oxygen d. stroke-death of nerve tissue due to blocked vessels in brain

40. Respiratory system • Uptake of oxygen from environment and release of carbon dioxide into environment • Requires a respiratory surface • Must by moist, thin and have a large surface area

41. 1. Nasal cavities warm, filter and moisten air 2. Larynx-contain vocal cords, opening is covered with epiglottis when swallowing 3. trachea-windpipe, held open with rings of cartilage

42. 4. bronchi-tubes into each lung 5. bronchioles-smaller and smaller branches 6. alveoli-air sacs where exchange takes place 7. diaphragm-breathing muscle

43. Breathing is controlled by two areas of the brain: the medulla oblongata and the pons • It is a response to change in pH of the blood

44. Problems 1. Bronchitis 2. Laryngitis 3. Emphysema 4. Lung cancer

45. Excretory system • Types of animal waste: • Ammonia-very toxic, animal must have lots of water to dilute it. Common in aquatic species. Requires the least amount of energy to produce • Urea-less toxic, can be stored, found in land animals because it requires less water to dilute • Uric acid-nontoxic, nonsoluble, excreted as dry paste, found in birds, insects and many reptiles. Requires the most energy to produce

47. Steps in excretion: • Filtration • Reabsorption • Secretion • Excretion

48. 1. Kidneys-bean shaped, reddish brown, fist sized • Made of millions of filtering units called nephrons • Cortex-outer region • Medulla-cone shaped regions between cortex and pelvis • Pelvis-hollow chamber where urine collects

49. 2. Ureter 3. Bladder-elastic sac 4. Urethra-tube to exit the body

50. Control of excretion 1. Antidiuretic hormone (ADH) -produced in the hypothalamus -increases water reabsorbtion, reduces urine volume -released when water is lost through sweating or eating salty foods