The Human Body: An Overview Chapter 1

An Overview… Anatomy – the study of the structure and shape of the body and body parts and their relationship with one another Physiology – the study of how the body and its parts work or function

Levels of Structural Organization Atom – the smallest unit of matter Molecule – two or more atoms Macromolecules – two or more molecules Cell – the smallest unit of life Tissue – group of cells that work together and have a common function Organ – group of tissues that work together… Organ system – group of organs… Organism – group of organ systems…

Organ System Overview Integumentary – skin Skeletal – provide framework for the body Muscular – provides movement Nervous – brain, spinal cord, and nerves Endocrine – produces hormones

Organ System Overview (cont.) Cardiovascular – heart and blood vessels Lymphatic – immune system Respiratory – lungs Digestive – esophagus, stomach, and intestines Urinary – elimination of liquid waste Reproductive - sperm, eggs, etc.

Maintaining Life Movement Responsiveness – the ability to sense changes (stimuli) in the environment and then react to them Digestion

Maintaining Life (cont.) Metabolism breaking down macromolecules into simple building blocks making larger structures from smaller ones using nutrients and oxygen to produce ATP molecules Excretion – removing waste from the body Reproduction Growth

Survival Needs Nutrients Oxygen – approximately 20% of the air is consist of this gas Water – 60% to 80% of body weight Body temperature – needs to be around 98°F Atmospheric pressure – aids in gas exchange and blood flow

Homeostasis Homeostasis – the body ability to maintain relatively stable internal conditions even though the outside world is changing Example Body temperature (very similar to a thermostat)

Homeostasis (cont.) Negative feedback mechanisms – return stimuli back to set point Homeostatic Balance of Body Temperature 105°F Body temp. increases Negative feedback External heat increases 98°F Set point www.scienceaid.co.uk 90°F

Anatomical Position Anatomical position – standing with palms held unnaturally forward with thumbs pointing away from the body

Directional Terms Superior – Toward the head; above Inferior – Away from the head; below Anterior – Toward the front Posterior – Toward the backside Medial – Toward the midline of the body Lateral – Away from the midline; the outer side of the body

Directional Terms (cont.) Intermediate – Between a medial and a lateral structure Ex. The armpit is intermediate between the breastbone and shoulder. Proximal – Close to Distal – Far from Superficial – Toward the body surface Deep – Away from the body surface; more internal

Directional Terms (cont.) Superior Inferior Anterior Posterior Medial Lateral Superficial Deep Proximal Distal Intermediate

Anterior Body Landmarks Abdominal – stomach Axillary – armpit Brachial – arm Carpal – wrist Digital – fingers, toes Femoral – thigh Nasal – nose Oral – mouth Orbital – eye area Patellar – anterior knee Pubic – genital region Sternal – breastbone Tarsal – ankle Thoracic – chest Umbilical - navel

Posterior Body Landmarks Cephalic – head Deltoid – curve of shoulder Gluteal – buttock Lumbar – lower spine region Occiptal – posterior part of head Popliteal – posterior knee area Scapular – shoulder blade Vertebral – spine area

Body Planes and Sections Plane – an imaginary line separating the body into sections Sagittal (median or midsagittal) – A cut made dividing the body into left and right equal parts Frontal – A cut made dividing the body into anterior and posterior parts Transverse – A cut made dividing the body into superior and inferior parts

Sagittal Frontal Transverse

Body Cavities Cavity – an empty space in the body Dorsal body cavity Cranial Spinal Ventral body cavity Throracic– chest Abdominal – stomach Pelvic – hip Abdominopelvic – combination of abdominal and pelvic cavities

Nine Regions of the Body Upper three Right (R.) and left (L.) hypochondriac hypo = below chondro = cartilage Epigastric Epi = above gastric = stomach Middle three R. and L. lumbar – lower spine Umbilical – navel Lower three R. and L. iliac – superior part of the hip Hypogastric