The Human Body

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Chapter 1

• The Human Body

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Introduction

• Anatomy the study of the structure of the body
• Physiology the study of the function of the body
  parts
• Pathology the study of the disease of the body
• Basic reference systems
• Directions, planes, cavities, structural units

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Terms of Direction
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Terms of Direction (contd.)
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Planes
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Planes (contd.)
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Cavities
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Cavities (contd.)

• Dorsal
• Cranial, spinal
• Ventral
• Thoracic, abdominopelvic
• Parietal walls of a cavity
• Visceral covering on an organ

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Cavities (contd.)
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Structural Units
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Structural Units (contd.)

• Cells
• Smallest units of life
• Perform all activities necessary to maintain life
• Metabolism, assimilation, digestion, excretion,
  reproduction

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Structural Units (contd.)

• Tissues
• Made up of different types of cells
• Epithelial covers and protects
• Connective binds and supports other tissues
• Muscle movement
• Nervous connects sensory structures to motor
  structures

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Structural Units (contd.)

• Organs
• Cells integrated into tissues
• Serve a common function
• Examples
• Liver
• Stomach
• System is a group of organs

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Structural Units (contd.)

• Integumentary system
• Organs
• Skin, hair, nails, sweat glands, sebaceous glands
• Functions
• Protection, insulation, regulation of water and
  temperature

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Structural Units (contd.)

• Skeletal system
• Organs
• Bones, cartilage, membranous structures
• Functions
• Movement, blood production, fat and mineral
  storage, protection

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Structural Units (contd.)

• Muscular system
• Organs
• Muscles, fasciae, tendon sheaths, and bursae
• Functions
• Movement, pushing food and blood, contracting
  heart

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Structural Units (contd.)

• Nervous system
• Organs
• Brain, spinal cord, cranial and peripheral
  nerves, sensory and motor structures
• Function
• Control and regulation, interpreting stimuli

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Structural Units (contd.)

• Endocrine system
• Organs
• Endocrine glands
• Function
• Works with nervous system to regulate chemical
  aspects of the body

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Structural Units (contd.)

• Cardiovascular system
• Organs
• Heart, arteries, veins, capillaries
• Function
• Transport substances to and from cells

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Structural Units (contd.)

• Lymphatic/immune system
• Organs
• Lymph nodes, lymph vessels, thymus gland, spleen
• Functions
• Drains tissues of excess fluids, transports fats,
  develops immunities

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Structural Units (contd.)

• Respiratory system
• Organs
• Nasal cavities, pharynx, larynx, trachea,
  bronchi, lungs
• Function
• O2 gt CO2 exchange in the blood

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Structural Units (contd.)

• Digestive system
• Organs
• Alimentary canal mouth, esophagus, stomach,
  small and large intestines, rectum and anus
• Associated glands salivary, liver, pancreas
• Functions
• Convert food into absorbable substances,
  eliminates wastes

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Structural Units (contd.)

• Urinary system
• Organs
• Kidneys, ureters, bladder, urethra
• Functions
• Chemical regulation of blood
• Formation and elimination of urine
• Maintenance of homeostasis

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Structural Units (contd.)

• Reproductive system
• Organs
• Women ovaries, uterine tubes, uterus, vagina
• Men testes, seminal vesicles, prostate gland,
  penis, urethra
• Functions
• Maintains sexual characteristics and perpetuates
  the species

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Homeostasis
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Homeostasis (contd.)

• Maintenance of the bodys internal environment
• Within varying narrow limits
• Negative feedback loop
• Examples
• Blood sugar levels
• Body temperature

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Homeostasis (contd.)

• Blood glucose
• Levels rise dramatically after meal
• Cells take in glucose
• Pancreas secretes insulin
• Moves glucose into liver for storage as glycogen
• Between meals, pancreas secretes glucagon
• Turns glycogen into glucose and returns it to
  blood
• Thus, glucose levels remain nearly constant

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Homeostasis (contd.)

• Body temperature
• Hypothalamus detects increase in body temperature
• Causes sweating
• Water evaporates and body is cooled
• Blood vessels dilate to bring blood near body
  surface

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Homeostasis (contd.)

• Body monitors deviations in homeostasis
• Negative feedback loop
• Responses that revise disturbances to bodys
  condition
• Positive feedback
• Increase in function in response to stimulus
• Uterine contractions during labor
• Organ systems help control internal environment

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Summary

• Discussed the four basic reference systems of
  body organization (directions, planes, cavities,
  and structural units)
• Discussed organization of the body into different
  structural levels (cells, tissues, organs,
  systems, human organism)
• Discussed homeostasis and mechanisms for
  maintaining it