Skeletal System

1. Skeletal System 7th Grade Advanced Science

2. What is the skeletal system made of? • The skeletal system is made of bone and cartilage. Images from biology.ucf.edu

3. Simple Fracture • Compound Fracture  Images from worldoforthopedics.com Bones are ALIVE. They are made of living cells and contain nerves and blood vessels. Bones can also grow and repair themselves.

4. Bone Composition • Bones contain mainly two minerals, calcium and phosphorus. • You get these minerals from your diet. • The hard outer layer of bones is hard, compact and dense. It is called compact bone. • The inside layer is called spongy bone. It is not as dense and porous.

5. Skeletal System Function • Bones serve the body in several ways: • Protection of body organs • Support the body and give it shape • Provide a place to muscles to attach so movement to take place. • Store minerals • Make red blood cells – this occurs in the marrow of long bones.

6. Joints • The place where bones meet is called a joint. • Some joints are fixed and cannot move. Example. Skull • Some joints are semi-movable: ribs, vertebrae. Fixed joint Semi-moveable  Images from www.saburchill.com

7. There are four kinds of movable joints: • Ball and socket – Allow the greatest range of motion. Examples: hip, shoulder • Hinge – Allow movement in one direction. Example: knee, elbow Ball and socket joint Hinge joint 

8. Moveable Joints • Pivot – Allow a twisting movement. Example: neck • Gliding – Allows bones to glide past one another. Example: wrist, ankle, spine  Gliding joint

9. Cartilage • Cartilage is found at the end of bones to keep them from rubbing against each other. • Without cartilage, bones would quickly wear and erode away. Image from www.memorialhermann.org/adam

10. Human Skeleton • The human body has 206 bones. • Babies have even more but the bones fuse together as the baby develops.

11. Bones To Know • - Cranium - Ulna - Tarsals • - Mandible - Carpals - Metatarsals • - Clavicle - Metacarpals • - Vertebrae - Phalanges • - Scapula - Pelvis • - Ribs - Femur • - Sternum - Patella • - Humerus - Tibia • - Radius - Fibula

12. Muscular System 7th Grade Advanced Science

13. Muscle Classification • Muscles are classified as either voluntary or involuntary. • Voluntary muscles are under your own control. • Involuntary muscles are not under conscious control. • There are three kinds of muscle tissue: • Skeletal • Cardiac • Smooth

14. Skeletal Muscle • These muscles are attached to the bones of the skeletal system. • Skeletal muscles are voluntary. • Skeletal muscles provide the forces that move your body. • They react quickly and tire quickly. • Are “striated” 

15. Involuntary muscle work automatically. These muscles are responsible for activities like breathing or digesting food. • Cardiac muscle is the involuntary muscle found only in the heart. • Cardiac muscle never tires. • Is also “striated” like skeletal muscle. • Smooth muscle control many activities of the body. • React and tire much more slowly than skeletal muscles. • Smooth muscle is not striated. • Smooth muscle is found in the digestive tract, blood vessels, respiratory tract, and eye.

16. How do muscles work? • Muscles work by contracting (growing shorter). Muscles can only contract, not extend. (can only pull, not push). • Skeletal muscles work in pairs. When one muscle contracts the other relaxes.

17. Exercise • Exercise is important for maintaining muscular strength and flexibility. • Individual muscles cells can grow wider, thicker, and stronger with exercise. Muscles will also not tire as quickly.

18. Muscles to Know - Biceps - Hamstring - Triceps - Gastrocnemius - Deltoids - Gluteus maximus - Latissmusdorsi - Quadriceps - Pectoralis major - Trapezius - Abdominals

19. Digestive System 7th Grade Advanced Science Image from www.sparknotes.com

20. Functions of Digestive System • The digestive system breaks down food into molecules that the body can use. This process is called digestion. • These molecules are absorbed into the blood and carried throughout the body. This process is called absorption. • The digestive system also eliminates waste from the body.

21. Types of Digestion • Mechanical Digestion – this refers to the physical breakdown of food into smaller pieces. • Chemical Digestion – this refers to the breakdown of complex molecules into simple molecules by enzymes. • Enzymes are proteins that speed up chemical reactions in the body.

22. Organs of the Digestive System GI Tract: Mouth  Esophagus  Stomach  Small Intestine  Large Intestine  Rectum  Anus Other important organs in digestion: - Liver - Pancreas - Gallbladder

23. Mouth • The mouth is where both chemical and physical digestion begins. • Teeth chew, tear, and slash food as physical digestion. • Saliva contains enzymes to aid in chemical digestion of starches. Image from embyology.med.unsw.edu

24. Esophagus • The esophagus is a muscular tube that connects the mouth to the stomach. When we swallow, muscles in the esophagus move food downward by waves of contractions. • A flap of tissue called the epiglottis prevents food/water from entering the trachea (windpipe). • Going down the wrong way? • What kind of muscle is in the esophagus?

25. Stomach • The stomach is a muscular pouch in the abdomen. • Most mechanical digestion occurs in the stomach, it makes a churning motion that mixes food with enzymes. • Chemical digestion is also taking place. Digestive juices in the stomach are very acidic and contain many different enzymes to break down different kinds of food. The acids also kill harmful bacteria you may swallow on accident. • Food remains in the stomach until all solid material has been broken down (about 2-3 hours after a meal).

26. Small Intestine • Most chemical digestion occurs in the small intestine. • Nearly all absorption of nutrients takes place here too. • “Small” intestine only refers to the diameter of the tube – the small intestine about 6 meters long! • Also has a huge surface area to aid in absorption.

27. Large Intestine • When food material reaches the end of the small intestine, most nutrients have been absorbed. • The function of the large intestine is water reabsorption. • Water is absorbed into the bloodstream as material passes through. • The large intestine ends in a short tube called the rectum. Waste is compacted here and exits the body through the anus.

28. The liver performs a variety of functions for the body. It plays role in detoxification of chemicals, and produces bile. • Bile is used to break down fat molecules and is stored in the gallbladder. • The pancreas is also important in many body processes. It produces many different kinds of digestive enzymes for breaking down different types of food.

29. Nutrition

30. Healthy Foods?

31. Unhealthy Foods?

32. Fast Food?

33. Health Risks • The typical American diet consists of high-fat, low-fiber foods. Research links this diet to many health risks. • Increased chance of stroke • May impede brain function • Increased chance of cancer • Increased chance of heart attack, arteriosclerosis, high blood pressure. Image from www.ehow.com

34. How much fat? • The FDA recommends a diet no higher than 30 percent fat, with less than 10 percent coming from saturated fats. • Twenty to 30 grams of fiber each day is also recommended.

35. Circulatory System 7th grade Advanced Science Image from www.biology4kids.com

36. Functions of the Cardiovascular System • The circulatory system is responsible for bringing needed materials (nutrients, oxygen) to the various tissues of the body. • The circulatory system also picks up waste (carbon dioxide) from cells. • It also transports cells that fight disease.

37. The Heart • The heart is a hollow muscular organ that pumps blood through the body. Each time the heart beats, it pushes blood through the blood vessels of the circulatory system. • Muscle in the heart consists of cardiac muscle. Image from www.fallingpixel.com

38. The heart has a right and left side, separated by a wall of tissue called the septum. Each side has two chambers – an atrium (upper) and a ventricle (lower). • The atria are separated from the ventricles by valves. • These are flaps of tissue that prevent blood from flowing backwards. • The heartbeat occurs in two muscle contractions. When the heart fills with blood, the atria contract and force blood to the ventricles. Then the ventricles contract and blood flows out through blood vessels. • The pacemaker is a group of cells that send signals to make the heart contract.

39. Image from www.biomaterials .org

40. The Flow of Blood • Arteries carry blood away from the heart. Arteries are thick and muscular (smooth). Why? • Veins carry blood back toward the heart. They are thinner and less have less smooth muscle. • There are two loops blood follows: (lub-dup) • 1: Blood travels from the heart to the lungs, picks up oxygen, and travels back to the heart. (lub) • 2: Blood travels from the heart, to body tissues, drops off oxygen/nutrients, and travels back to the heart. (dup).

41. Eventually, blood flows from large arteries to smaller ones, and from small arteries to capillaries. • Capillaries are where material is exchanged between blood and cells of the body. • Oxygen and glucose pass from blood to the cells, and waste and CO2 pass from the cells to blood. Image from www.merck.com

42. What’s in blood? • Red blood cells – are the oxygen carrying cells of the body. Hemoglobin is the protein that carries oxygen. • Most blood cells are red blood cells • White blood cells – are the body’s disease fighting cells. • Are larger and less numerous than red blood cells • Platelets – fragments of cells that help blood clot. • Plasma – the liquid mixture of nutrients and water that blood cells are suspended in.

43. Blood pressure is the force against the blood vessel walls, caused by the contracting ventricles. • Check your pulse. Your pulse is the alternating expansion and relaxation of your artery walls. The walls expand when the heart’s ventricles contract and send a spurt of blood through the arteries. • Counting pulses is counting heartbeats!

44. Cardiovascular Health • Cardiovascular disease is the leading cause of death in the U.S. • Atherosclerosis is a condition in which the artery wall thickens because of a build up of fatty materials (cholesterol). • If arteries become blocked, this can lead to a heart attack. • Hypertension is a high blood pressure disorder. • Both these conditions are related. As arteries narrow, pressure increases. • What can we do to maintain a healthy cardiovascular system?

45. Prevention • Exercise Regularly!! The heart is a muscle, and exercise will help strengthen your heart. • Eat a balanced diet. Foods high in fat can cause buildup of fats in arteries. • Don’t Smoke!! Years of research indicate that smoking is a cause of heart disease and failure.

46. Respiratory System 7th grade Advanced Science

47. Function • The respiratory system moves oxygen from the outside environment into the body. It also removes carbon dioxide and water from the body.

48. Structure of the Respiratory System • Air enters the body through the nasal cavity. Tiny hairs (cilia) and mucus trap particles and warm and moisten the air. • Air moves down through the pharynx and larynx. • The trachea, a tube made of cartilage, also has cilia and mucus. • What causes us to cough? • What causes us to choke?

49. Air moves from the trachea to the bronchi, the two tubes that direct air to the lungs. • The lungs are the main organs of the respiratory system. Inside the lungs, each bronchus divides into smaller and smaller branches like a tree. • At the end of each branch are the alveoli, which are the where gases are exchanged (diffusion) between the air and blood. • The walls of the alveoli and capillaries are very thin. After air enters the alveoli, oxygen passes from air to blood and carbon dioxide passes from blood to the lungs. Image from www.realscienceproject.com

50. How Do We Breathe? • Breathing is controlled by muscles. The diaphragm is a large muscle under your ribs that plays an important role in breathing. Image from www.fotolibria.com