The Human Body: An Orientation

An overview of the human body systems

1. CHAPTER 1 – THE HUMAN BODY: AN ORIENTATION ANATOMY & PHYSIOLOGY

2. AN OVERVIEW OF ANATOMY AND PHYSIOLOGY CHAPTER 1

3. Let’s start with the basics anatomy : the study of the structure and shape of the body and its parts and their relationships to one another gross anatomy : the study of large body structures (human body) microscopic anatomy : the study of body structures too small to be seen with the naked eye (cells and tissues)   physiology : the study of how the body and its parts work or function

4. They are ALWAYS related The parts of the body form a well-organized unit You want to view the body in terms of structure and function Cardiovascular system

5. Why must we use levels of organization? LEVELS OF ORGANIZATION

6. The basics Each level contains progressively larger structures The structure in each level is composed of structures from the preceding level

7. Level 1 – Chemical Level Smallest level of organization From atoms up to molecules atoms : the building blocks of all matter ex. H, H 2 O

8. Level 2 – Cellular Level cells : the smallest unit of all living things Ex. neuron

9. Level 3 – Tissue Level tissue : consist of groups similar cells that have a common function 4 basic types (epithelial, connective, muscular, neural) ex. neural tissue

10. Level 4 – Organ Level organ : structure composed of two or more tissues types that performs a specific function at this level, extremely complex functions become possible ex. brain

11. Level 5 – Organ System Level organ system : a group of organs that work together to accomplish a common purpose ex. CNS

12. Level 6 – Organismal Level Organismal Level organism : an individual living thing composed of multiple organ systems working together Humans use 11 organ systems

13. AN OVERVIEW THE HUMAN ORGAN SYSTEMS

14. 11 Organ Systems We will examine each system in more detail later in the year Look at both the structures involved and how each of these structures function both independently and together Take note how the organ systems are interrelated

15. Integumentary System structure: skin (external covering of the body) function: 1. waterproofs the body 2. cushions and protects deeper tissues from injury 3. excretes salts and urea during perspiration 4. helps regulate body temperature

16. Skeletal System structure: bones, cartilages, ligaments, joints function: 1. supports the body 2. provides a framework for skeletal muscles 3. protects some organs 4. performs hematopoiesis hematopoiesis : formation of blood cells

17. Muscular System structure: skeletal muscles function: to contract and to allow movement viewed as the “machines” of the body allows for locomotion, maintains posture, produces heat, etc.

18. Nervous System structure: brain, spinal cord, nerves, sensory receptors (body’s fast-acting control system) function: 1. respond to external stimuli 2. respond to internal stimuli assesses information and responds by activating the appropriate body effectors (muscles or glands)

19. Endocrine System structure: pituitary, thyroid, parathyroids, adrenals, thymus, and pineal glands, pancreas, ovaries/testis function: 1. controls body activities (slower than the nervous system) 2. produce and release hormones

20. Cardiovascular System structure: heart and blood vessels function: 1. carries oxygen, nutrients, hormones, and other substances to and from tissue cells where exchanges are made 2. WBCs help protect the body from foreign invaders (bacteria, toxins, tumor cells)

21. Respiratory System structure: nasal passages, pharynx, larynx (vocal cords), trachea, bronchi and lungs, function: 1. keeps body constantly supplied with oxygen 2. removes carbon dioxide from the body thin walls of the air sacs allows gases to be transported to and from the lungs

22. Lymphatic System structure: lymphatic vessels, lymph nodes, spleen, tonsils function: 1. returns fluid leaked from the blood back to the blood vessels 2. help cleanse the blood and house cells involved in immunity complements the cardiovascular system

23. Digestive System structure: (mouth -> anus) oral cavity (mouth), esophagus, stomach, small and large intestines, rectum, anus function: 1. breakdown food 2. deliver products to the blood for dispersal to the body cells 3. reclaim water (large intestines) liver is a digestive organ because it produces bile, which helps break down fats pancreas delivers digestive enzymes to the small intestines, functionally a digestive organ

24. Diagram of the Digestive System

25. Urinary System (Excretory System) structure: kidneys, ureters , bladder, urethra function: 1. removes Nitrogen-containing wastes from the blood in the form of urine 2. helps maintain salt and water balance (electrolyte) 3. regulates the acid-base balance of the blood

26. Reproductive System structure: in males: testes, scrotum, penis, accessory glands, and duct system in females: ovaries, uterine tubes, uterus, vagina function: to produce offspring

27. What things must happen in individual organ systems and between multiple organ systems to allow the human body to function? NECESSARY LIFE FUNCTIONS

28. The basic idea all organisms must use and maintain necessary life functions organ systems are interdependent it is important to establish which organ systems are most directly related to each life function

29. What must happen: 1. Maintain Boundaries 2. Movement 3. Responsiveness 4. Digestion 5. Metabolism 6. Excretion 7. Reproduction 8. Growth

30. Maintaining Boundaries Maintaining Boundaries every living organism needs to maintain boundaries to keep “insides” distinct from “outsides” every individual cell has a membrane (most semi- or selectively permeable) (microscopic anatomy) the body is enclosed by the Integumentary system (gross anatomy) protects internal organs from drying out protects internal organs from bacteria protects body from the damaging effects of heat, sunlight, chemical substances, and the external environment

31. Movement movement : all activities promoted by the muscular system muscular system provides the muscles skeletal system provides the bones the muscles pull on as they work movement also occurs when substances are propelled through the internal organs of the cardiovascular, digestive and urinary systems

32. Responsiveness responsiveness : (also called irritability ) is the ability to sense changes in the environment and react to them the nervous system is the most responsible for responsiveness however, all body cells are irritable to some extent.

33. Digestion digestion : the process of breaking down ingested food into simple molecules that can be absorbed into the blood in the complex body this is performed by the digestive system

34. Metabolism metabolism : a broad term that refers to all chemical reactions that occur within body cells includes: breaking down complex molecules into simpler ones using Oxygen and nutrients to produce molecules of ATP (adenosine triphosphate , the energy-rich molecules that power cell activities) depends on the respiratory, digestive, and cardiovascular systems mainly regulated by hormones secreted by the glands on the endocrine system

35. Excretion excretion : the process of removing excreta (wastes) from the body nonuseful substances produced during digestion and metabolism must be removed several organ systems participate in excretion, including the digestive and urinary systems

36. Reproduction reproduction : the production of offspring can occur at both the cellular and organismal levels ex. mitosis in cells, human reproduction task of the reproductive system, regulated precisely by the hormones of the endocrine system

37. Growth growth : an increase in size, usually accomplished by an increase in the number of cells for growth to occur, cell-constructing activities must occur at a faster rate than cell-destroying ones

38. What are the basic substances necessary for human survival? SURVIVAL NEEDS

39. Survival Needs several factors necessary for maintaining life nutrients, Oxygen, water, appropriate temperature and atmospheric pressure must be present in appropriate amounts; too much or too little may be equally harmful

40. Survival Needs 1. Nutrients body takes in through food contain the chemicals used for energy and cell building proteins, carbohydrates, etc 2. Oxygen the chemical reactions that release energy from foods require Oxygen approximately 20% of the air we breathe is Oxygen (20.95%)

41. Survival Needs 3. water 60-80 % body weight, 65-75% in muscle, only 10% in fat 50-60% in most people, women have a lower percentage due to higher body fat single most abundant chemical substance in the body provides the fluid base for body secretions and excretions (secretion is an active process/particle movement, excretion is a passive process/waste removal) chiefly ingested from foods and liquids lost by evaporation and body excretions

42. Survival Needs 4. body temperature must be maintained around 37°C or 98.6°F as temperature drops, metabolic reactions slow until they stop as temperature rises, metabolic reactions speed up and can proceed too rapidly at either extreme, death will occur most body heat is generated by the activity of skeletal muscles

43. Survival Needs 5. atmospheric pressure atmospheric pressure : the force exerted on the surface of the body by the weight of the air breathing and the exchange of oxygen and carbon dioxide in the lungs depend on appropriate atmospheric pressure

44. WHAT IS HOMEOSTASIS? WHY IS IT IMPORTANT? HOMEOSTASIS

45. Homeostasis homeostasis : a state of body equilibrium or stable internal environment of the body literally means “unchanging” ( homeo = the same, stasis = standing still) dynamic state of equilibrium ex. blood pressure, waste accumulation, body temperature

46. Homeostasis communication is key, and is mainly controlled by the nervous and endocrine systems nerves bloodborne hormones The factor being regulated by homeostasis is the variable

47. Homeostasis all homeostatic control mechanisms have at least three components: 1. A receptor 2. A control center 3. An effector

48. A receptor a receptor that responds to environmental changes some type of sensor that monitors and responds to change stimulus : the change (pl. stimuli) sends information(input) to the second element (the control center) along the afferent pathway the afferent pathway approaches the control center

49. A control center a control center that assesses changes determines the level at which a variable is to be maintained analyzes the information it receives determines the appropriate course of action or response

50. The effector provides the means for the control center’s response (output) to the stimulus information flows from control center to the effector along the efferent pathway efferent information exits from the control center the results of the response feedback to influence the stimulus either depresses (negative feedback) or enhances (positive feedback)

51. Negative Feedback Systems Negative feedback mechanisms : the net effect of the response to the stimulus is to shut off the original stimulus or reduce its intensity most homeostatic control mechanisms ex. Home thermostat hypothalamus in the body also includes heart rate, blood pressure, breathing rate, blood nutrient levels

52. Positive Feedback Systems Positive feedback mechanisms : tend to increase the original disturbance (stimulus) and to push the variable farther from its original value rare in the body events that occur explosively ex. Blood clotting, birth

53. Homeostatic Imbalance Homeostasis is so important that most diseases can be regarded as homeostatic imbalances as age increases, organ function decreases, and the risk of disease/homeostatic imbalance as increases