Chapter 1 An Introduction to the Human Body

1. 1-1 Chapter 1An Introduction to the Human Body Anatomy science of structure relationships revealed by dissection (cutting apart) imaging techniques Physiology science of body functions normal adult physiology studied in this text some genetic variations described Subdivisions of A & P

2. 1-2 Levels of Organization Chemical Cellular Tissue Organs System Level Organismic Level

3. 1-3 Levels of Structural Organization Chemical Level atomic and molecular level Cellular level smallest living unit of the body Tissue level group of cells and the materials surrounding them that work together on one task 4 basic tissue types epithelium, muscle, connective tissue, and nerve

4. 1-4 Levels of Structural Organization Organ level grouping of 2 or more tissue types into a recognizable structure with a specific function. Organ system collection of related organs with a common function sometimes an organ is part of more than one system Organismic level one living individual.

5. 1-5 Interaction of Organ Systems All major body systems will be examined Interaction of different systems of the body skin produces vitamin D needed for calcium absorption and bone growth bone marrow produces cells which help the skin resist infection.

6. 1-6 Life Processes Metabolism = sum of all chemical processes breakdown of large molecules into small building new structural components (proteins) providing chemical energy for cells Responsiveness detect & respond to changes in internal or external environment some typical responses muscle contraction, electrical signals, hormone or glandular secretion

7. 1-7 Life Processes Movement at any structural level the body, an organ, a cell or cell component Growth increase in number or size of cells or the material found between cells Differentiation specialization of cells for a specific function stem cells give rise to cells that specialize Reproduction formation of new cells or new individuals

8. 1-8 Homeostatis Maintaining the internal environment within physiological limits Example blood glucose level is kept within narrow range 70-110/100ml

9. 1-9 Control of Homeostasis Homeostasis is continually being disrupted by external stimuli or intense heat, cold , and lack of oxygen internal stimuli psychological stresses exercise Disruptions are usually mild & temporary If homeostasis is not maintained, death may result

10. 1-10 Neural and Endocrine Controls Process of maintaining a controlled condition sensory receptors detect change in a monitored variable nervous system and/or endocrine system responds Example: control of blood gas level exercise increases blood CO2 levels sensory receptors detect change nervous system increases heart and breathing rates to remove excess CO2 adrenal gland releases epinephrine to increase heart and breathing rates

11. 1-11 Components of Feedback Loop Receptor monitors a controlled condition Control center determines next action Effector receives directions from the control center produces a response that changes the controlled condition

12. 1-12 Negative & Positive Feedback Loops Negative feedback loop original stimulus reversed most feedback systems in the body are negative used for conditions that need frequent adjustment body temperature, blood sugar levels, blood pressure Positive feedback loop original stimulus intensified seen during normal childbirth

13. 1-13 Homeostasis of Blood Pressure Pressure receptors in walls of certain arteries detect an increase in BP blood Pressure = force of blood on walls of vessels Brain receives input and signals heart and blood vessels Heart rate slows and arterioles dilate (increase in diameter) BP returns to normal

14. 1-14 Positive Feedback during Childbirth Stretch receptors in walls of uterus send signals to the brain Brain releases hormone (oxytocin) into bloodstream Uterine smooth muscle contracts more forcefully More stretch, more hormone, more contraction etc. Cycle ends with birth of the baby & decrease in stretch

15. 1-15 Homeostatic Imbalances Disorder = abnormality of function Disease = homeostatic imbalance with distinct symptoms---changes in body function felt by the patient such as nausea and signs----changes in body function that can be observed by the doctor such as rash or fever Diagnosis---skill of distinguishing one disease from another Epidemiology----how disease is transmitted Pharmacology --- how drugs used to treat disease

16. 1-16 Basic Anatomical Terminology Anatomical position Regions of the body Anatomical planes, sections and directional terms

17. 1-17 Anatomical Position Standardized position from which to describe directional terms standing upright facing the observer, head level eyes facing forward feet flat on the floor arms at the sides palms turned forward Prone position = lying face down Supine position = lying face up

18. 1-18 Planes and Sections A plane is an imaginary flat surface that passes through the body. A section is one of the 2 surfaces (pieces) that results when the body is cut by a plane passing through it.

19. 1-19 Sagittal Plane Sagittal plane divides the body or an organ into left and right sides Midsagittal plane produces equal halves

20. 1-20 Other Planes and Sections Frontal or coronal plane divides the body or an organ into front (anterior) and back (posterior) portions Transverse(cross-sectional) or horizontal plane divides the body or an organ into upper (superior) or lower (inferior) portions

21. 1-21 Planes and Sections of the Brain(3-D anatomical relationships revealed) Horizontal Plane Frontal Plane Midsagittal Plane

22. 1-22 Major Directional Terms

23. 1-23 Superior or Inferior Superior towards the head The eyes are superior to the mouth. Inferior away from the head The stomach is inferior to the heart.

24. 1-24 Dorsal or Posterior at the back of the body The brain is posterior to the forehead. Ventral or Anterior at the front of the body The sternum is anterior to the heart. Dorsal or Ventral

25. 1-25 Medial or Lateral Medial nearer to the midline of the body The heart lies medial to the lungs. Lateral farther from the midline of the body The thumb is on the lateral side of the hand.

26. 1-26 Proximal or Distal Proximal nearer to the attachment of the limb to the trunk The knee is proximal to the ankle. Distal farther from the attachment of the limb to the trunk The wrist is distal to the elbow.

27. 1-27 Dorsal Body Cavity Near dorsal surface of body 2 subdivisions cranial cavity holds the brain formed by skull vertebral or spinal canal contains the spinal cord formed by vertebral column

28. 1-28 Ventral Body Cavity Near ventral surface of body 2 subdivisions thoracic cavity above diaphragm abdominopelvic cavity below diaphragm Diaphragm = large, dome-shaped muscle Organs called viscera

29. 1-29 Abdominopelvic Cavity Inferior portion of ventral body cavity below diaphragm Encircled by abdominal wall, bones & muscles of pelvis

30. 1-30 Medical Imaging Allows visualization of structures without surgery Useful for confirmation of diagnosis Examples of imaging techniques

31. 1-31 Conventional Radiography A single burst of xrays Produces 2-D image on film Known as radiography or xray Poor resolution of soft tissues Major use is osteology

32. 1-32 Computed Tomography (CT Scan) Moving x-ray beam Image produced on a video monitor of a cross-section through body Computer generated image reveals more soft tissue detail kidney & gallstones Multiple scans used to build 3D views

33. 1-33 Angiogram Radiopaque material injected into blood vessels Before and after images compared with a computer program Image of blood vessel is shown on a monitor

34. 1-34 Ultrasound (US) High-frequency sound waves emitted by hand-held device Safe, noninvasive & painless Image or sonogram is displayed on video monitor Used for fetal ultrasound and examination of pelvic & abdominal organs, heart and blood flow through blood vessels

35. 1-35 Magnetic Resonance Imaging (MRI) Body exposed to high-energy magnetic field Protons align themselves relative to magnetic field Pulse of radiowaves used to generate an image on video monitor Can not use on patient with metal in their body Reveals fine detail within soft tissues

36. 1-36 Positron Emission Tomography(PET) Substance that emits positively charged particles is injected into body Collision with negatively charged electrons in tissues releases gamma rays Camera detects gamma rays & computer generates image displayed on monitor