Transcript Chapter 3
Chapter 1 An Introduction to the Human Body 1 Anatomy science of structure subdivisions summarized in table 1.1 Physiology science of body functions normal adult physiology is studied in this text some genetic variations are described Table 1.1 2 Levels of Organization Chemical Cellular Tissue Organs System Organism 3 LEVELS OF ORGANIZATION Figure 1.1 The chemical level Atoms Molecules Cells Basic structural & functional units of an organism Tissues Groups of similarly specialized cells that perform certain special functions 4 LEVELS OF ORGANIZATION Organs Structures of definite form Two or more different tissues Specific functions Systems Related organs with a common function Organism Collection of structurally & functionally integrated systems; any living individual 5 BODY SYSTEMS Integumentary Cardiovascular Skeletal Lymphatic Muscular Respiratory Nervous Endocrine Urinary Digestive Reproductive 6 Clinical Application Noninvasive techniques used to assess certain aspects of body structure & function: Inspection Palpation Auscultation Percussion 7 Basic Life Processes Metabolism: Catabolism Anabolism Responsiveness: Movement: 8 Basic Life Processes Growth: hyperplasia, hypertrophy, or both Differentiation: Reproduction formation of new cells for growth, repair, or replacement production of a new individual ***Death Loss of heartbeat Loss of brain function Absence of spontaneous breathing 9 HOMEOSTASIS State of balance in body’s internal environment produced by the ceaseless interplay of all the body’s regulatory processes “dynamic equilibrium” narrow range of conditions compatible w/ life Recurring theme of textbook 10 Body Fluids Intracellular fluid = fluid inside body cells Extracellular fluid (ECF) = fluid outside cells Interstitial fluid (ISF) = ECF in narrow spaces between cells of tissues internal environmt Plasma = ECF in blood vessels Exchange of nutrients across capillaries to/from ISF/cells & tissues 11 Control of Homeostasis Homeostasis continually disrupted by External stimuli • intense heat or cold • lack of oxygen Internal stimuli • psychological stresses • low blood sugar Disruptions are usually mild & temporary If homeostasis not maintained, death may result 12 CONTROL OF HOMEOSTASIS How do we maintain homeostasis in wake of internal/external disruptions? Number of regulatory mechanisms restore balance Nervous & endocrine systems • nervous system rapid response • endocrine system slow response Feedback systems 13 Feedback Systems Information about status of a condition is continually monitored & reported (fed back) to central control region Monitored variable = controlled condition Any disruption that changes a controlled condition is called a stimulus. 3 basic components • Receptors • Control center • Effector 14 Components of Feedback Loop Receptor Monitors Δ in controlled condition Input to control center • Nerve impulses • Chemical signals (hormones) Control center Evaluates receptor input Generates output Effector Receives output from control ctr Produces response that changes controlled condition 15 Negative Feedback Systems A negative feedback system reverses a change in a controlled condition. Homeostasis of Blood Pressure (BP): Negative Feedback (Figure 1.3) The activity of the effector produces a result (a drop in blood pressure) that opposes the stimulus (an increase in blood pressure). 16 Positive Feedback System Reinforces a change (enhances original stimulus) in a controlled condition Normal childbirth 17 Positive Feedback during Childbirth receptors in walls of uterus send signals to brain Brain releases a hormone (oxytocin) into bloodstream Uterine smooth muscle contracts more forcefully More stretch more hormone more contraction etc. The cycle ends with birth of the baby & decrease in stretch Stretch 18 Homeostatic Imbalances Disruption of homeostasis can lead to disease and death. Disorder = general term for any derangement or abnormality of function Disease = specific term for illness characterized by a recognizable set of signs and symptoms Local disease affects one part or a limited region of body (rash) Systemic disease affects either entire body or several parts (ex: flu) Cancer begins locally and if left untreated can become systemic 19 Homeostatic Imbalances Characterizing disease Signs • fever, blood pressure, rash, swelling Symptoms • headache, nausea Diagnosis Distinguishing one disease from another Determining the nature of a disease Medical history & physical examination 20 BASIC ANATOMICAL TERMINOLOGY 21 Anatomical Position When in anatomical position, the subject is: standing upright facing observer, with head level eyes facing forward feet flat on floor arms at sides palms turned forward (ventral) 22 Reclining Position If the body is lying face down, it is in the prone position. If the body is lying face up, it is in the supine position. 23 Directional Terms Used to precisely locate one part of the body relative to another Commonly used directional terms: inferior, superior, medial, and distal summarized in Exhibit 1.1 and Figure 1.6. Also see lab manual 24 Major Directional Terms See Definitions page 14 25 Superior/Inferior Refer to placement of structure along long axis of body Superior “Above” eyes are superior to mouth Inferior “Below” stomach is inferior to heart 26 Anterior/Posterior Anterior (ventral) At the front of body Sternum is anterior to heart Posterior (dorsal) At the back of body Brain is posterior to forehead 27 Medial/Lateral Refers to location of structure in relation to median plane/midline of body Medial Nearer to midline of the body Heart lies medial to lungs Lateral Farther from midline of the body Thumb is on lateral side of hand 28 Proximal/Distal Primarily for location of areas of limbs Proximal nearer to attachment of limb to trunk Knee is proximal to ankle Distal farther from attachment of limb to trunk Wrist is distal to elbow 29 Planes and Sections Imaginary flat surfaces used to divide body or organs into definite areas Principal planes include: midsagittal (medial) and parasagittal frontal (coronal) transverse (cross-sectional or horizontal) oblique Sections flat surfaces resulting from cuts through body structures named according to plane of cut 30 Sagittal Planes Sagittal plane Midsagittal plane divides the body or an organ into left and right sides produces equal halves Parasagittal plane produces unequal halves 31 Other Planes and Sections Frontal (coronal) plane Transverse/cross-sectional/ horizontal plane front (anterior) & back (posterior) portions upper (superior) or lower (inferior) portions Oblique plane some combination of 2 other planes 32 Planes and Sections of the Brain (3-D anatomical relationships revealed) Horizontal Plane Frontal Plane Midsagittal Plane 33 Body Cavities Body cavities are spaces within the body that help protect, separate, and support internal organs. 34 Dorsal Body Cavity Located near dorsal surface of body Cranial cavity • formed by the cranial bones • contains the brain Vertebral (spinal) canal (Figure 1.9) • formed by bones of vertebral column • contains spinal cord Lined by three layers of protective tissue called meninges Inflammation of meninges = meningitis 35 Ventral Body Cavity Near ventral surface of body 2 subdivisions thoracic cavity above diaphragm abdominopelvic cavity below diaphragm Organs called viscera Organs covered with serous membrane 36 Ventral Body Cavity Thoracic cavity Contains all chest organs; surrounded by rib cage Contain fluid-filled cavities surrounding heart/lungs • Pleural cavities • Pericardial cavity Mediastinum Abdominopelvic cavity Inferior to diaphragm, surrounded by abdominal wall Abdominal viscera: mostly digestive organs Pelvic viscera: urinary bladder, inferior lg intestine, & internal reproductive structures 37 Mediastinum Partition between lungs that extends from sternum to vertebral column Contains all organs of thoracic cavity except lungs 38 Serous Membranes Double layered membrane lining body cavities not open to outside parietal layer visceral layer Serous fluid btwn layers reduces friction Serosa compartmentalize organs Infection of one organ is contained Specific names of membranes 39 Serous Membranes Pleural membrane surrounds lungs Pericardium = serous membrane of pericardial cavity Peritoneum = serous membrane of abdominal cavity 40 Pleural & Pericardial Cavities Visceral and Parietal Pleura Pleurisy = inflammation of pleural membrane Visceral and Parietal Pericardium 41 Abdominopelvic Cavity Inferior portion of ventral body cavity below diaphragm Encircled by abdominal wall, bones & muscles of pelvis 42 Peritoneum Serous membrane of abdominopelvic cavity Visceral peritoneum covers abdominal viscera Parietal peritoneum lines abdominal wall Peritoneal cavity = fluid-filled space btwn layers Intraperitoneal organs suspended within peritoneal membranes (most abdom. organs) Retroperitoneal organs located behind abdominal wall (kidneys, colon, adrenal glands) 43 **The blue and green regions on this diagram represent the peritoneal cavity. Note that there are NO organs within the actual cavity. It is simply a fluidfilled space as are the pericardial & pleural cavities. 44 http://www.lab.anhb.uwa.edu.au/hsd212/02weekpages/WK07/week07_5more1.htm Abdominopelvic Regions & Quadrants Describe locations of organs or source of pain Tic-tac-toe grid or intersecting lines through navel 45