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The Human Body: An Orientation Part 1

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AnatomyAna- (apart) -tomy (to cut) The study of internal & external structures of the body and the physical relationships between body parts

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AnatomyGross Anatomy

study of large and easily observable structures considers features visible with the unaided eye surface anatomy

Microscopic anatomy study of very small structures with the use of microscope or magnifying lens considers structures that cannot be seen without magnification e.g. cells, tissues

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PhysiologyDerived from physio = nature; ology = the study ofThe study of how living organisms perform their vital functions. It considers the physical & chemical processes responsible for the characteristics of life.

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Relationship Between Anatomy & Physiology

The parts of the body form a well-organized unit and each of these parts has a job to do to make the body operate as a wholeStructure determines what functions can take place

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Levels of Structural OrganizationFrom Atoms to Organisms

Chemical level• Atoms and molecules

Cellular level• Cells are the smallest units of all living things• Cells vary according to their function

Tissue level• Tissues consist of group of similar cells that have a common

function• Epithelial, connective, muscular and neural

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Levels of Structural OrganizationFrom Atoms to Organisms

Organ level• Organ is a structure composed of 2 or more tissue

types that performs a specific function for the body• Complex functions are possible

Organ System• Group of organs that operate to accomplish a common

purpose Organismal level

• Highest level of structural organization

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Organ System OverviewIntegumentary System

forms the waterproof skin or the external body covering cushions and protects the deeper tissues from injury helps regulate body temperature excretes salts and urea in perspiration contains temperature, pressure and pain receptors synthesizes vitamin D

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Organ System Overview

Skeletal System consists of bones, cartilages, ligaments and joints supports and protects body organs provides leverage for locomotion site of hematopoiesis or blood cells formation storehouse of minerals

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Organ System Overview

Muscular System formed by skeletal muscles allows manipulation of the environment, locomotion and facial expression helps to maintain posture produces heat

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Organ System Overview

Nervous System composed of brain, spinal cord, nerves, sensory receptors the body’s fast-acting control system responds to internal and external changes by activating appropriate effectors (muscles and glands)

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Organ System Overview

Endocrine System consists of ductless glands that secrete hormones to regulate bodily processes such as growth, reproduction and metabolism includes the pituitary, thyroid, parathyroids, adrenals, thymus, pancreas, pineal, ovaries and testes not connected anatomically

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Organ System Overview

Cardiovascular System the heart and blood vessels are the primary organs carries oxygen, nutrients, hormones and other substances to and from the tissues cells where exchanges are made protection from foreign invaders

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Organ System Overview

Lymphatic System includes lymphatic vessels, lymph nodes and other lymphoid organs returns leaked fluids from blood to the blood vessels so that blood can be kept continuously circulating through the body cleanses the body and contains cells involved in immunity

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Organ System Overview

Respiratory System consists of nasal passages, pharynx, larynx, trachea, bronchi and lungs keeps blood constantly supplied with oxygen and removes carbon dioxide

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Organ System Overview

Digestive System basically a tube running through the body from the mouth – esophagus – stomach – intestines – rectum – anus also includes the liver and pancreas breaks down food and delivers the product to the blood for dispersal eliminates undigested food as feces reclaims water in the large intestine

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Organ System Overview

Urinary System / Excretory System composed of kidney, ureters, bladder and urethra eliminates nitrogenous wastes from the body regulates water, electrolytes and acid-base balance of the blood

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Organ System Overview

Reproductive System for the production of offspring Male Reproductive System

• Testes, scrotum, penis, accessory glands and duct system

Female Reproductive System• Ovary, uterine tubes, uterus and vagina

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Necessary Life FunctionsMaintaining Boundaries

Membranes• Keep the inside distinct from the outside

Skin• Protects internal organs from drying out, from

bacteria and from damaging effects of heat, sunlight and chemical substances

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Necessary Life FunctionsMovement

Propelling oneself from one place to another Manipulating the external environment Propelling blood, foodstuffs and urine through the organs

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Necessary Life FunctionsResponsiveness / Irritability

ability to sense changes in the environment and then to react to them

Digestion process of breaking down ingested food into simpler molecules that can then be absorbed into the blood for delivery

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Necessary Life FunctionsMetabolism

Chemical reactions that occur within the body cells

• Catabolism Breaking down complex substances into simpler

building blocks• Anabolism

Making larger structures from smaller ones

Regulated chiefly by hormones secreted by the glands of the endocrine system

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Necessary Life FunctionsExcretion

process of removing wastes from the body get rid of the useless substances produced during digestion and metabolism

Reproduction the production of offspring cellular or organismal level mitosis/ meiosis

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Necessary Life FunctionsGrowth

increase in size brought about, usually, by an increase number of cells cell-constructing activities must occur at a faster rate than cell-destroying ones

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Maintaining LifeSurvival Needs

Nutrients • Carbohydrates, Fats, Proteins, vitamins and minerals

Oxygen• Needs for release of energy from food

Water• 60-80% of body weight

Blood Temperature (370C or 980F) Atmospheric pressure

• Force exerted on the surface of the body by weight of air

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HomeostasisThe body’s ability to maintain relatively stable internal conditions even though the outside world is continuously changingIndicates a dynamic state of equilibriumImbalances will lead to development of diseases and illnessess

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Feedback MechanismsNegative Feedback Mechanism

the net effect of the response to the stimulus is to shut off the original stimulus or reduce its intensity thermostat action of hypothalamus, heart rate, BP, etc.

Positive Feedback Mechanism rare in the body causes an increase in the intensity of the original stimulus blood clotting and birth of a baby