Chapter 1 An Introduction to the Human Body

1. Chapter 1 An Introduction to the Human Body Lecture slides prepared by Curtis DeFriez, Weber State University

2. Anatomy and Physiology • Human Anatomy is the study of body structure. • Word is derived from the Greek and means “to cut” or “cutting backwards” (putting things together from slices). • Human Physiology is the science of body functions. • Including the study of homeostasis (keeping the organs systems of the body in balance)

3. Anatomy and Physiology • Structure and function of the body are closely related: Structure mirrors function • Bones of the skull are heavy and secure to protect brain function. • The thin air sacs of the lungs permit movement of gases from the lungs to the blood.

4. Subdivisions of Anatomy • Surface Anatomy is the study of form and markings of the body surface, often explored through visualization or palpation (without any “cutting”). • Gross Anatomy is the study of anatomical structures visible to unaided eye. After making the appropriate surface marking in the prior picture, the gross dissection proceeds through “cutting.”

5. Subdivisions of Anatomy • Gross Anatomy can be studied by two general approaches: • Systemicapproach (Systemic Anatomy): • Study all of the blood vessels, or all of the muscles, or all of the bones… at once. • Regionalapproach (Regional Anatomy) • All anatomical structures of a specific region (e.g. the thorax, or the Head and Neck) are all studied together.

6. Subdivisions of Anatomy • Histologyis the study of tissues. • Cytology,like histology, uses a microscope, but restricts the study to individual cellular structures . This micrograph is typical of an histological and cytological examination under light microscopy

7. Subdivisions of Anatomy • Pathologyis the study of anatomical changes due to disease . • Pathologists use gross inspection, as well as cytologic, histologic, and laboratory examinations to discover the source of the disease. This is a section of a human colon opened by a pathologist to reveal polyps that would become cancerous in a few years (premalignant).

8. Clinical Connection • An autopsy is a postmortem (after death) examination of the body and internal organs performed by a pathologist. • An autopsy is usually done to : • Determine the cause of death • Identify diseases not detected during life • Determine the extent of injuries and contribution to death • Identify hereditary conditions

9. Introduction and Skeletal System Unit 1 • Anatomy- (ana=up) (tomy=process of cutting) is the science of body structures and the relationships among structures • Physiology-(physio=nature) (logy=study of) is science of body functions • Histology-(Hist=tissue) study of microscopic structures of tissues • Morphology-(morph=form) study of shape, form and structure • Dissection-(dis=apart) (section=act of cutting)careful cutting apart body structures to study their relationship

10. Medical terms • Palpation-(palp=gently touch) examiner feels body surfaces with the hands (Ex) finding pulse • Auscultation-(auscult=listening) examiner listens to body sounds, usually through a stethoscope (Ex) listening to lungs during breathing for crackling sounds of fluid in lungs • Percussion-(percus=beat through) examiner taps on body surface with fingertips to listen for an echo (Ex) to find out air might be in intestines , also information about size of underlying structures • Autopsy-(seeing with ones own eyes) postmortem (after death) examination of the body and dissection of internal organs to confirm or determine cause of death ( disease, genetic causes, drowning, etc)

11. Levels of Organization • Tissues are groups of cells that work together to perform a similar function. • While there are many different types of cells, they all work to form 4 basic types of tissues: • Epithelium • ConnectiveTissue • Muscle • Nerves

12. Levels of Structural Organization Atoms- smallest unit of matter that participates in chemical reactions-(Ex) carbon-(C), Oxygen-(O) Molecules-2 or more atoms joined together-(Ex) DNA, glucose Organelles-Structures in Eukaryotic cells that have a specific function-(Ex) ribosomes, nucleus, etc. Cells- Basic structural and functional unit of an organism, smallest living unit in organism, comes from other cells (Ex) nerve cells, bone cells Tissue-groups of cells and surrounding material that work together to carry out a specific function (Ex) connective, nervous, muscle, etc.

13. Continued-organization • Organs-are structures that are composed of two or more different types of tissues that carry out a specific function (Ex) stomach, liver • Organ System-Consists of related organs that have a common function (Ex) digestive, respiratory, etc • Organism-is any living individual (Ex) human

14. Levels of Organization • An organismconsists of a collection of organ systems. • Six important life processes: • Metabolism • Responsiveness • Movement • Growth • Differentiation • Reproduction • In health, all parts of the body must be functioning together in a process called homeostasis.

15. Homeostasis • A condition of equilibrium (balance) in the body’s internal environment. It is a dynamic condition meant to keep body functions in the narrow range compatible with maintaining life. • Blood glucose levels range between 70 and 110 mg of glucose/dLof blood.

16. Homeostasis and its importance • Homeo=sameness, stasis=standing still • Condition of equilibrium in the body’s internal environment • This is a dynamic condition—means it fluctuates • Int. environment remains constant even though the Ext. environment changes • Importance—Keeps internal environment within normal limits—Ex—Blood glucose

17. Homeostasis Interactions Animation • Communication, Regulation and Homeostasis You must be connected to the internet to run this animation.

18. Homeostasis • Body fluids are defined as dilute, watery solutions containing dissolved chemicals inside or outside of the cell. Maintaining the volume and composition of body fluids is important. • Intracellular Fluid (ICF) is the fluid within cells • Extracellular Fluid (ECF)is the fluid outside cells • Interstitial fluid is ECF between cells and tissues • Dissolved in the water of ECF and ICF are Oxygen, nutrients, proteins, and ions

19. Homeostasis • Some important body fluids: • Blood Plasma is the ECF within blood vessels. • Lymph is the ECF within lymphatic vessels. • Cerebrospinal fluid (CSF) is the ECF in the brain and spinal cord. • Synovial fluid is the ECF in joints. • Aqueous humor is the ECF in eyes.

20. Feedback System • Cycle of events: • Body is monitored and re-monitored. • Each monitored variable is termed a controlled condition. • Three basic components: • Receptor • Control center • Effector

21. Feedback System • A receptoris a body structure that monitors changes in a controlled condition (such as body temperature) and sends input to the control center. • Specialized nerve endings in the skin act as temperature receptors – they cause a nerve to fire in response to temperature changes.

22. Feedback System • Thecontrol center sets the range of values to be maintained – usually this is done by the brain. • Evaluates input received from receptors and generates outputcommand • Output involves nerve impulses, hormones, or other chemical agents. • Brain acts as a control center receiving nerve impulses from skin temperature receptors.

23. Feedback System • The effectorreceives output from the control center and produces a response or effect that changes the controlled condition. • Nearly every organ or tissue can serve as an effector. • Body temperature drops. • The brain sends an impulse to the skeletal muscles to contract . • Shivering occurs to generate heat.

24. Feedback System • Negative Feedback systems: • Reverses a change in a controlled condition • Regulation of blood pressure (force exerted by blood as it presses again the walls of the blood vessels) • Positive Feedback systems: • Strengthens or reinforces a change in one of the body’s controlled conditions • Normal child birth

25. Feedback Systems—Fig 1-2, pg 9 • Feedback system—is a cycle of events in which the status of a body condition is continually monitored, evaluated, remonitored, reevaluated, and so on • Receptor—monitors change and sends input to control center—ex—nerve endings in skin • Control center—sets range of values that should be maintained then sends output-Ex-hormones • Effector—body structure that receives output and produces response that changes the controlled condition • Controlled condition-(variable)—Body temperature, blood glucose, blood pressure

26. Negative Feedback System-these help maintain homeostasis • Reverses the original stimulus or controlled condition, it returns the controlled condition back to the normal state • Example—Blood pressure—when the heart beats faster blood pressure increases, nerve impulses are sent out to decrease the heart rate, which decreases blood pressure • Thirst • Stretch reflexes • Blood sugar (insulin) • Vomiting(Physiological-something bad in system)

27. Positive Feedback System-can cause life threatening conditions • Tends to strengthen or reinforce a change in one of the body’s controlled conditions(Enhances or intensifies original stimulus) it keeps happening until interrupted by some mechanism outside the system • Example—Normal Childbirth—First contractions then hormones cause more contractions interrupted only by birth of the child, which stops the process • Blood clotting • Heat stroke (Hyperthermia) over 105 degrees • Vomiting (Psychological-this causes more )

28. Negative Feedback – Temperature Interactions Animation • Negative Feedback Control of Temperature You must be connected to the internet to run this animation.

29. Feedback System • Blood Pressure regulation is a negative feedback system. • External or internal stimulus increases BP. • Baroreceptors (pressure sensitive receptors) detect higher BP and send a nerve impulse to the brain (interpretation). • Responses sent via nerve impulses to the heart and blood vessels cause the BP to drop (homeostasis is restored.)

30. Blood Pressure RegulationInteractions Animation • Negative Feedback Control of Blood Pressure You must be connected to the internet to run this animation.

31. Feedback System • Childbirth is an example of a positive feedback system: • Uterine contractions cause vagina to open. • Stretch-sensitive receptors in cervix send impulses to brain. • Oxytocin is released into the blood. • Contractions enhanced and baby pushes farther down the uterus. • Cycle continues to the birth of the baby (no stretching).

32. Positive Feedback – LaborInteractions Animation • Positive Feedback Control of Labor You must be connected to the internet to run this animation.

33. Medical problems • Disorder-is any derangement or abnormality of function • Disease-more specific term for an illness characterized by a recognizable set of signs and symptoms(local-affects one part or limited region of body) (systemic-affects entire body or several parts of it)—Diseases alter body structures and functions in certain ways • Signs-objetcive changes that a clinician can observe and measure(swelling, rash, paralysis, fever, HBP) • Symptoms-subjective changes in body functions that are not apparent to observer(Headache, nausea, anxiety) • Diagnosis-(dia-through) (gnosis-knowledge) science and skill of distinguishing one disorder or disease from another, takes into consideration medical history, physical exam, and laboratory tests

34. Clinical Connection • Diagnosis of Disease is done by assessing: • Signs and symptoms • Medical history • Collecting information about event • Present illnesses and past medical problems • Physical examination: • Orderly evaluation of the body and its function • Noninvasive techniques and other vital signs (pulse)

35. Organ Systems of the Body • The systems of the body may appear to be separate and distinct, but the maintenance of most body functions requires the integration of many systems working together. • For example, regulation of body temperature involves the muscular, cardiovascular, nervous, and integumentary systems all working together to produce and distribute body heat appropriately.

36. Body Planes • Sagittalplanes divide the body into right and left sides. • There is only one midsagittal plane, and it divides the body into two equal, mirror-image halves. • There are an infinite number of possible parasagittal planes to the right and left of the midsagittal that divide the body into unequal “halves”.

37. Body Planes • Frontal or coronal planes divide the body (or an organ) into anterior (front) and posterior (back) portions. • Transverse planes (also called cross-sectional or horizontal planes) divide the body into superior (upper) and inferior (lower) portions.

38. Body Planes • In addition to the right angle sagittal, coronal and transverse planes, the body can also be divided into an infinite number of oblique planesthat pass through the body or organ at an angle. • Sections are cuts of the body made along a plane.

39. The 4 Basic Tissues • Of all the cells in the body, they combine to make only 4 basic tissue types: • Epithelial tissues • Connective tissues • Muscular tissues • Nervous tissues

40. The 4 Basic Tissues • Connective tissues (C.T.) protect, support, and bind organs. • Fat is a type of C.T. that stores energy. • Red blood cells, white blood cells, and platelets are all C.T.

41. Connective Tissue • Connective Tissues are the most abundant and widely distributed tissues in the body – they are also the most heterogeneous of the tissue groups. • They perform numerous functions: • Bind tissues together • Support and strengthen tissue • Protect and insulate internal organs • Compartmentalize and transport • Energy reserves and immune responses

42. Connective Tissues • Collagen is the main protein of C.T. and the most abundant protein in the body, making up about 25% of total protein content. • Connective tissue is usually highly vascular and supplied with many nerves. • The exception is cartilage and tendon - both have little or no blood supply and no nerves.

43. Connective Tissues • Although they are a varied group, all C.T. share a common “theme”: • Sparse cells • Surrounded by an extracellular matrix • The extracellular matrix is a non-cellular material located between and around the cells. • It consists of protein fibers and ground substance (the ground substance may be fluid, semifluid, gelatinous, or calcified.)

44. Cells Of Connective Tissues • Common C.T. cells • Fibroblasts are the most numerous cell of connective tissues. These cells secrete protein fibers (collagen, elastin, & reticular fibers) and a “ground substance” which varies from one C.T. to another.

45. Cells of Connective Tissues • Of the other common C.T. cells: • Chondrocytes make the various cartilaginous C.T. • Adipocytes store triglycerides. • Osteocytes make bone. • White blood cells are part of the blood.

46. Connective Tissues • C.T. cells secrete 3 common fibers: • Collagen fibers • Elastin fibers • Reticular fibers

47. Connective Tissue Classification • Embryonic connective tissue • Mesenchyme • Mucous connective tissue • Mature connective tissue • Loose connective tissue • Dense connective tissue • Cartilage • Bone • Liquid

48. Embryonic Connective Tissues • There are 2 Embryonic Connective Tissues: • Mesenchyme gives rise to all other connective tissues. • Mucous C.T. (Wharton's Jelly) is a gelatinous substance within the umbilical cord and is a rich source of stem cells.

49. Mature Connective Tissues • Loose Connective Tissues • Areolar Connective Tissue is the most widely distributed in the body. It contains several types of cells and all three fiber types. • It is used to attach skin and underlying tissues, and as a packing between glands, muscles, and nerves. • Adipose • Reticular

50. Mature Connective Tissues • Loose Connective Tissues • Loose areolar • Adipose tissue is located in the subcutaneous layer deep to the skin and around organs and joints. • It reduces heat loss and serves as padding and as an energy source. • Reticular