The Human Body

Chapter 1

Human Anatomy and Physiology

Anatomy: The study of body structures and their relationshipsStatic within a species

Physiology: The study of the functions of body structuresDynamic within a species

Subdivision Examples

Anatomy• Gross anatomy

– Regional– Systemic– Surface

• Microscopic anatomy– Cytology– Histology

• Embryology• Developmental anatomy• Others

Physiology• Neurophysiology• Pathophysiology• Cardiovascular physiology• Renal Physiology• Others

Life is an Emergent Property

• Atoms• Molecules• Organelles• Cells• Tissues• Organs• Organ systems

– Listed in fig 1.3• Organismal level

Organ SystemsORGAN SYSTEM COMPONENTS FUNCTIONS

Integumentary Skin, hair, nails Protection

Skeletal Bones Support/movement

Nervous Brain, spinal cord, nerves, sense organs

Control and communication

Muscular Muscles Movement

Endocrine Hormones and associated glands Homeostasis

Cardiovascular Heart, blood vessels, blood Transport of substances

Lymphatic Lymph vessels and lymph nodes Transport, immunity

Respiratory Nose, trachea, lungs Transport of gases

Digestive Mouth, esophagus, stomach, intestines

Energy acquisition and food processing

Urinary Kidneys, ureters, bladder, urethra Water balance

Reproduction Gonads Propagation

Life’s Essentials

• Maintain boundaries• Move • Respond to

environment• Digestion• Excretion• Metabolism• Reproduce• Grow

Survival Essentials• Nutrients

– Fuel for the cells– Building materials

• Oxygen– Release energy from nutrients

• Water– Facilitates reactions and excretions/secretions

• Normal body temperature– Regulate metabolic reactions

• Atmospheric pressure– Corresponds with gas exchange w/i cells

• Adequate amounts, not just presence maintains a healthy state

Homeostasis

• Dynamic state of equilibrium• 3 components

– Receptor (afferent)– Control center (set point)– Effector (efferent)

• Imbalance causes illness & disease – Increase with age– Disruptions in feedback

Feedback

• Negative– Most homeostatic mechanisms

• Turn off or slow original stimuli• Stabilizes

– Body temperature, heart and breathing rate, & blood glucose

• Positive– Increases the original stimuli– Oxytocin (labor) and blood clotting

ANATOMICAL LANGUAGE

Anatomical Position

• Standing tall with upper limbs at sides and face, palms and toes forward

• Reference position when describing body part locations– Left and right is specimen’s– Variations for bipeds and quadrupeds

Anatomical Regions to Know

Anatomical Directions to Know Superior/ inferior

Cranial/caudalVentral/ dorsal

Anterior/ posteriorMedial/ lateralIntermediate/ proximal/

distalSuperficial/ deep

External/ internalSupine/ proneIpsilateral/ contralateral

Study tip: pick two structures on self and describe as many ways as possible

Body Planes are Like Breads

• Sagittal section: divides the body longitudinally into left and right– Midsagittal: equal

parts – Parasagittal: off

midline– e.g.: hotdog bun

• Frontal (coronal) section: divides anterior and posterior– e.g.: loaf of bread

• Transverse (cross) section: divides superior and inferior– e.g.: hamburger bun or bagel

– Oblique section: diagonal cuts

Body Cavities

• Dorsal– Cranial: brain– Vertebral: spinal cord

• Ventral– Thoracic

• Left & right pleura• Mediastinum (pericardial)

– Abdominopelvic• No real separation• Protection differences• Diaphragm divides

Serous Membranes

• Double-layer membrane separated by serous fluid– Reduces friction; lubricates

• Line walls and organs of ventral body cavities– Parietal serosa lines walls– Visceral serosa lines organs

(viscera)– Named for associated organs

• Never exposed to external environment

Other Body Cavities

• Open to environment (generally)

Abdominopelvic SubdivisionsRegions (9)

• Anatomists use; references location and orientation of internal organs

Quadrants (4)

• Clinicians use; references to describe pain, tenderness, and injuries

Epigastric Umbilical Hypogastric Hypochondriac Lumbar Inguinal