1. The Human Body: An Orientation Department of Applied Science King Saud University/ Community College By: YASSIN ABOBAKER A.

2. Outline Survival Needs Language of Anatomy Anatomical Position Regional Terms Directional Terms Body Planes and Sections Body Cavities Homeostasis The Human Body: An Orientation

3. Survival Needs Nutrients –Taken in through the diet –Macronutrients Carbohydrates – energy Proteins – energy; building cell structures Lipids – stored energy; building cell structures; cushioning –Micronutrients Vitamins and minerals – chemical reactions; oxygen transport

4. Oxygen –Necessary for the production of energy –C 6 H 12 O 6 +O 2  CO 2 + H 2 O + energy Water –60 – 80 % of body weight –Necessary for Secretions, excretions Transport of substances Chemical reactions

5. Body Temperature –Maintained at about 37 degrees C –Necessary for metabolism Higher and enzymes breakdown Lower and reactions slow and then stop Atmospheric Pressure –Force on the surface of the body due to the weight of air –Necessary for breathing

6. Language of Anatomy Special language created to give precise information about the location of body structures Latin and Greek roots, prefixes and suffixes Eponyms –Many are being replaced with more precise, descriptive terms –Islets of Langerhans – pancreatic islets

7. Anatomical Position Reference position Body erect with arms at sides and palms forward. Head & feet pointing forward. Bilateral symmetry: is a term meaning that right & left sides of body are mirror images. 1) Ipsilateral structures: are on the same side of the body in anatomical position. 2) Contralateral structures: are on opposite sides of the body in anatomical position. Regional Terms – –Anterior Body Landmarks –Posterior Body Landmarks

8. Directional Terms They are Terms used in describing body structure Used to explain exactly where one body structure is in relation to another –Assume anatomical position Superior (cranial): means “toward the head” Inferior (caudal): toward the feet Anterior (ventral): in front of Posterior (dorsal): in back of Medial: toward the midline of the body Lateral: toward the side of the body Proximal: nearest the trunk of the body Distal: away from the trunk Superficial: nearer the surface Deep: farther away from the body surface

9. Body Planes and Sections Planes and Sections –Plane – imaginary line separating body parts –Section – cut along the plane (named for the plane) Transverse plane –Divides the body into superior and inferior sections –Transverse section or cross section Frontal (Coronal) plane –Divides the body into anterior and posterior sections

10. Sagittal plane –Divides the body into unequal right and left sections Midsagittal plane –Divides the body into equal right and left sections

12. Body Cavities The body can be divided into an: 1) Appendicular portion (upper and lower limbs or extremities). 2) Axial portion (head, neck, and trunk) The body is not a solid structure, it contains two cavities: 1) Ventral cavity. 2) Dorsal cavity. Organs within these cavities are called viscera.

13. Dorsal Cavity –Cranial – brain –Spinal – spinal cord Ventral Cavity –Thoracic Cavity –Abdominopelvic Cavity –Separated by the diaphragm

14. Body Cavities Protect the organs Permit the organs to change in size and shape –Heart contraction –Stomach distend with food Two major cavities –Dorsal –Ventral

17. Thoracic Cavity –Pleural – lungs –Mediastinum – esophagus, trachea, heart –Pericardial – heart only Abdominopelvic Cavity –Abdominal – digestive viscera –Pelvic – bladder, reproductive organs

18. Cavities in the Head w/ Viscera Sinus – air filled cavities in cranial bones Orbital cavity - eyeball Nasal cavity – air and mucus Oral cavity – teeth and tongue Middle ear cavity – connects ear with atmospheric pressure via pharynx

19. Abdominopelvic Cavity Quadrants – 4 –Right and left upper quadrant –Right and left lower quadrant Regions – 9 –Right and left hypochondriac –Right and left lumbar –Right and left iliac –Epigastric –Umbilical –Hypogastric

20. Body Regions 1.The abdominal area can be divided intonine regions. 2.Terms used to refer to various body regions.

21. Homeostasis Homeo - sameness Stasis - standing still Homeostasis –Ability of the body to maintain relatively stable internal environment regardless of external environment Dynamic changing state which operates within a range not a set point –Body temperature 37º F –Homeostasis range 36.5º C – 37.5º C

22. Homeostatic Control Mechanisms Nervous and Endocrine system –Nervous system Electrical signals - impulses –Endocrine system Hormones transported in blood to target cells Receptor –Monitors the environment –Detects changes Stimuli – changes in the environment

23. Control Center –Integration center –Determines the set point within the range –Analyzes the information –Determines the response Effector –Provides the response Muscles contract or relax Glands secrete or stop secreting

25. Feedback mechanisms Homeostasis maintained through either: –Negative feedback mechanisms opposes response to stimulus –Positive feedback mechanisms enhances response to stimulus

26. Negative Feedback Mechanisms Opposes (limits the intensity) or eliminates the original stimulus Negative means that the variable changes in a direction opposite to the initial change Negative feedback maintains body functions within a range Most homeostatic mechanisms in the body involved negative feedback Mechanisms ignore minor variations but maintain homeostasis within a range

28. Positive Feedback Mechanisms The response enhances or exaggerates the original stimulus Positive means that the change occurs in the direction of the original stimulus Rarely used to promote homeostasis Examples –Childbirth – pressure receptors; effector muscles of uterus; contraction to push baby through birth canal –Blood clotting – increase in number of platelets sticking to the broken blood vessel

30. Homeostatic imbalance Most diseases and/or disorders result from homeostatic imbalance With aging: –body organs and control systems become less efficient –internal environment becomes less and less stable –greater risk of illness/injury

31. Thank you for listening Yassin Abobaker A.