Introduction to the Human Body

Anatomy

• “tome” means to cut in Greek• Describes the structures of the body:– what they are made of– where they are located– associated structures

• All physiological functions are performed by specific anatomical structures

• Principle of complementarity says that structure and function are complementary – Function always reflects structure– What a structure can do depends on its specific

form

• Key to anatomy is understanding function– For example:

Left side of heart is larger than right.– Why is that?

Structure (anatomy) and function (physiology) are intimately related

Gross Anatomy

• Structures large enough that one can see with the unaided eye– Surface Anatomy - study of superficial markings– Regional Anatomy - The study of specific areas of

the body (e.g. head, trunk)– Systemic Anatomy - Study of the 11 specific organ

systems

Microscopic Anatomy

• Involves studying anatomical structures that cannot be seen with the unaided eye

1. Cytology - cells2. Histology - tissue

Levels of Organization• Chemical Level: - atoms (e.g. carbon) combine

to form molecules (e.g. glucose)• Cellular level:– Smallest living units in organisms– Cells contain organelles, each with a function

• Tissue level - different groups of cells that perform a function

• Organ Level - Different types of tissues that perform a common function

• Organ system – consists of different organs that work closely together

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Smooth muscle cellMolecules

Atoms

Smoothmuscletissue

Epithelialtissue

Heart

Bloodvessels

Smoothmuscletissue

Connectivetissue

Bloodvessel(organ)

Cardiovascularsystem

Cellular levelCells are made up ofmolecules.

Tissue levelTissues consist ofsimilar types of cells.

Organ levelOrgans are made upof different typesof tissues.

Organ system levelOrgan systems consist ofdifferent organs thatwork together closely.

Organismal levelThe human organismis made up of manyorgan systems.

Chemical levelAtoms combine toform molecules.

Levels of Structural Organization

11 Organ systems

IntegumentaryNervousSkeletalEndocrineMuscularCardiovascular

LymphaticUrinaryRespiratory ReproductiveDigestive

Body systems:1-INTEGUMENTARY

ORGANS• Skin

FUNCTIONS• Waterproofs, cushions, protects

deeper tissue• Excretes salts, pain, pressure• Regulates body temp, synthesize

vitamin D

2-SKELETAL

ORGANS• Bones, cartilages, ligaments,

joints

FUNCTIONS• Protects & supports body

organs• Framework for muscles &

movement• Store minerals

3- MUSCULAR

ORGANS• Skeletal muscle (attached to

bone)

FUNCTIONS• Contraction & mobility

(locomotion)• Facial expression, posture• Produce body heat

4- NERVOUS

ORGANS• Brain, spinal cord, nerves, &

sensory receptors

FUNCTIONS• Fast-acting central control

system• Responds to external/internal

stimuli via nerve impulses (electrical messages)

5- ENDOCRINE

ORGANS• Pituitary, thyroid,

parathyroids, adrenals, thymus, pancreas, pineal, ovaries, testes…...

FUNCTIONS• Slow-acting control system• Glands produce hormones

that regulate growth, reproduction, metabolism…..

6- Circulatory

ORGANS• Heart, blood vessels, capillaries

&blood

FUNCTIONS• Carries O2 nutrients, hormones,

& other substances to and from tissue cells

• White blood cells protect against bacteria, toxins, tumors

7- LYMPHATIC

ORGANS• Lymphatic vessels, lymph

nodes, spleen, tonsils

FUNCTIONS• Complements circulatory

system by returning leaked fluid back to blood vessels

• Cleanses the blood; involved in immunity

8- RESPIRATORY

ORGANS• Nasal cavity, pharynx, larynx,

trachea, bronchi & lungs

FUNCTIONS• Keeps blood supplied with O2

& removes CO2

• Carries out gas exchanges through air sacs in lungs

9- DIGESTIVEORGANS• Oral cavity, esophagus,

stomach, small intestine, large intestine, rectum, anus (liver & pancreas)

FUNCTIONS• Breaks food down into

absorbable units that enter the blood; indigestible food eliminated as feces

10- URINARY (EXCRETORY)

ORGANS• Kidney, ureter, urinary

bladder, urethra

FUNCTIONS• Eliminates nitrogenous waste

from the body (urea & uric acid)

• Regulates water, electrolytes, & acid-base balance of the blood

11- REPRODUCTIVEORGANS• Male

– Seminal vesicles, prostate, penis, vas deferens, testis, scrotum

• Female– Ovaries, mammary glands, uterus,

vagina, uterine tube

FUNCTIONS• Primary function for both sexes is to

produce offspring• Male – testes produce sperm & male

sex hormones• Female – ovaries produce eggs &

female sex hormones; mammary glands for nourishment

Anatomical terms

Anatomical Position

– Standing erect– Feet parallel– Arms hanging at the sides– Palms facing forward

Anatomical Position• Hands at sides, palms forward

Orientation of terms

• Note that Left/Right are reversed in anatomical figures

• WHY?

Directional terms• Superior (cranial) – toward the head end or upper

part of a structure or body; above• Inferior – away from the head end or toward the

lower part of a structure or body; below• Anterior (ventral) – toward or at the front of the

body; in front of• Posterior (dorsal) – toward or at the backside of the

body; behind• Medial – toward or at the midline of the body; on

the inner side of• Lateral – away from the midline of the body; on the

outer side of

• Proximal – close to the origin of the body part or the point of attachment of a limb to the body trunk.

• Distal – farther from the origin of a body or the point of attachment of a limb to the body trunk.

• Superficial (external) – toward or at the body surface.

• Deep (internal) – away from the body surface; more internal.

1. The navel is --------------to the breastbone2. The heart is ------------- to the breastbone3. The arms are ------------ to the chest4. The elbow is ------------ to the wrist5. The skin is ------------- to the skeleton6. The forehead is ------------------ to the nose7. The breastbone is------------ to the spine8. The heart is ------------to the arm9. The armpit is ---------between the breastbone

and the shoulder10.The knee is ---------to the thigh11.The lungs are ---------to the rib cage

Examples:• The navel is inferior to the breastbone• The heart is posterior to the breastbone• The arms are lateral to the chest• The elbow is proximal to the wrist• The skin is superficial to the skeleton• The forehead is superior to the nose• The breastbone is anterior to the spine• The heart is medial to the arm• The knee is distal to the thigh• The lungs are deep to the rib cage

Body planes and sections A section is a cut made along a plane• Sagittal – cut made along the lengthwise or

longitudinal plane of the body dividing it into left and right parts

• Midsagittal (median) plane – right and left parts are of equal size

• Frontal (coronal) plane – cut made along a lengthwise plane that divides the body into anterior and posterior parts

• Transverse plane (cross section) – cut made along a horizontal plane dividing the body or organ into superior and inferior parts

Planes

• Sagittal Plane – divides body into right and left parts.

• Midsagittal =median plane –divides body into two equal halves.

Planes

• Frontal = coronal plane – divides body into anterior and posterior parts

Planes

• Transverse plane = cross

Section= horizontal section divides into upper and lower parts

Body planes and sections - cut into sections along a flat surface called a plane

(also called XS – cross section)

(also called coronal)

Anatomical Movements

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• Supine – Lying on your back

• Prone – Lying face down

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Movements:

• Flexion – decreasing the angle between two joints• Extension – increasing the angle between two joints• Hyperextension – occurs beyond extended position

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• Abduction – moving away from the midline of the body or body part

• Adduction – moving toward midline of body or body part

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• Elevation – moving to superior position

• Depression – moving to inferior position

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• Supination – rotating forearm laterally

• Pronation – rotating forearm medially

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• Inversion – lifting the medial border of the foot

• Eversion – lifting the lateral border of the foot

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• Dorsiflexion – moving the top of the foot toward the shin

• Plantar flexion – moving the sole of the foot downward (pointing toes)

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• Circumduction – flexion, abduction, extension & adduction in a sequence

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• Rotation – Turning about the vertical axis of the bone