The Human BodyAn Orientation
The Human BodyAn Orientation
AnatomyStudy of the structure and shape of the body
and its parts
PhysiologyStudy of how the body and its parts work or
function
Anatomy—Levels of
Study
Gross anatomy
Large structures
Easily observable
Mouth (oral cavity)
Tongue
Esophagus
Liver
Gallbladder
Small intestineDuodenumJejunum
lleum
Anus
Parotid gland
Salivary glandsSublingual glandSubmandibulargland
Pharynx
StomachPancreas(Spleen)
Large intestine
Descendingcolon
Cecum
Sigmoid colonRectum
Appendix
Anal canal
Transversecolon
Ascendingcolon
Anatomy—Levels of
Study
Microscopic Anatomy
Structures cannot be seen with the naked
eye
Structures can only be viewed
with a microscope
Pyloricsphincter
Gastric pits
Surfaceepithelium
Mucousneck cells
Parietal cells
Gastricglands
Chief cells
Gas
tric
pit
Gas
tric
gla
nd
Organismal levelHuman organisms are made up of many organ systems.
Organ system levelOrgan systems consist of different organs that work together closely.
Organ levelOrgans are made up of different types of tissues.
Chemical levelAtoms combine toform molecules.
Smooth muscle cell
Cellular levelCells are made up of molecules.
Molecules
2
Atoms
1
Tissue levelTissues consist of similar types of cells.
3
Smoothmuscletissue
Epithelialtissue
Smoothmuscletissue
Connectivetissue
Bloodvessel(organ)
4
5
Cardio–vascularsystem
6
Bloodvessels
Heart
Organ System OverviewIntegumentary
Forms the external body covering
Protects deeper tissue from injury
Helps regulate body temperature
Location of cutaneous nerve receptors
Skin
Integumentary SystemForms the external body covering; protects deeper tissue from
injury; synthesizes vitamin D; location of cutaneous (pain, pressure, etc.) receptors and sweat and oil glands.
SkeletalProtects and
supports body organs
Provides muscle attachment for
movement
Site of blood cell formation
Stores minerals
Protects and supports body organs; provides a framework the muscles use to cause movement; blood
cells are formed within bones; stores minerals.
Cartilages
Joint
Bones
MuscularProduces movement
Maintains posture
Produces heat
Allows manipulation of the environment, locomotion, and facial expression; maintains
posture; produces heat.
Skeletalmuscles
NervousFast-acting control system
Responds to internal and external change
Activates muscles and glands
Fast-acting control system of the body; responds to internal and external changes by activating appropriate
muscles and glands.
Brain
Sensory
receptor
Spinal
cord
Nerves
EndocrineSecretes regulatory
hormones
Growth
Reproduction
Metabolism
(e) Endocrine SystemGlands secrete hormones that regulate processes such as growth, reproduction, and nutrient use by body cells.
Ovary (female)
Testis (male)
Pancreas
Adrenal glands
Thymus gland
Thyroid gland(parathyroid glandson posterior aspect)
Pituitary gland
Pineal gland
Cardiovascular
Transports materials in
body via blood pumped
by heart
Oxygen
Carbon dioxide
Nutrients
Wastes
(f) Cardiovascular System
Heart
Blood vessels transport blood, which carries oxygen,
carbon dioxide, nutrients, wastes, etc.; the heart pumps
blood.
Blood
vessels
LymphaticReturns fluids to blood
vessels
Cleanses the blood
Involved in immunity
Picks up fluid leaked from blood vessels and returns it to blood;disposes of debris in the lymphatic stream; houses white blood
cells involved in immunity.
Lymphnodes
Lymphaticvessels
Thoracicduct
RespiratoryKeeps blood supplied with oxygen
Removes carbon dioxide
Keeps blood constantly supplied with oxygen and removes carbon dioxide; the gaseous exchanges occur
through the walls of the air sacs of the lungs.
Pharynx
Nasalcavity
Larynx
Trachea
Bronchus
Left lung
DigestiveBreaks down food
Allows for nutrient absorption into blood
Eliminates indigestible material as feces
Breaks food down into absorbable units that enter the blood for distribution to body cells; indigestible foodstuffs
are eliminated as feces.
Oral cavity
Esophagus
Stomach
Smallintestine
Anus
Rectum
Largeintestine
UrinaryEliminates
nitrogenous wastes
Maintains acid-base balance
Regulates water and electrolytes
Eliminates nitrogen-containing wastes from the body; regulates water, electrolyte, and acid-base
balance of the blood.
Kidney
Ureter
Urinarybladder
Urethra
ReproductiveProduces offspring
Testes produce sperm and male hormone
Ovaries produce eggs and female hormones
Overall function of the reproductive system is production of offspring. Testes produce sperm and male sex hormone; ducts and glands aid in delivery of viable sperm to the female reproductive tract. Ovaries produce eggs and female sex hormones; remaining
structures serve as sites for fertilization and development of the fetus. Mammary glands of female breast produce milk to nourish the newborn.
Prostategland
Penis
Seminalvesicles
Vasdeferens
Testis
Scrotum
Vagina
Ovary
Uterinetube
Mammary
glands
(in breasts)
Uterus
Necessary Life Functions
MovementLocomotion
Movement of
substances
Necessary Life Functions
ResponsivenessAbility to sense changes
and react
DigestionBreakdown and
absorption of nutrients
MetabolismChemical reactions
within the body
Break down complex
molecules into smaller
ones
Build larger molecules
from smaller ones
Produces energy
Regulated by
hormones
ExcretionEliminates waste from metabolic reactions
Wastes may be removed in urine or feces
ReproductionOccurs on cellular level or organismal level
Produces future generation
GrowthIncreases cell size and number of cells
Survival Needs
NutrientsChemicals for energy and cell building
Includes carbohydrates, proteins, lipids, vitamins,
OxygenRequired for chemical reactions
Water60 to 80 percent of
body weight
Most abundant
chemical in the human
body
Provides for metabolic
reaction
Stable body temperature
37°C (98°F)
Atmospheric pressure Must be appropriate for gas exchange
Homeostasis
Homeostasis Maintenance of a
stable internal environment
A dynamic state of equilibrium
Necessary for normal body functioning and to
sustain life
Homeostatic imbalanceA disturbance in homeostasis resulting in disease
Input: Information sent along afferent pathway to control center.
Receptor
ControlCenter
EffectorReceptor
detects change.
Afferent
pathway
Efferent
pathway
VARIABLE (in homeostasis)
Stimulusproduceschange invariable.
Output: Information sent along efferent pathway to effector.
Responseof effector feedsback to reducethe effect ofstimulus andreturns variableto homeostatic level.
1
2
3 4
5
VARIABLE (in homeostasis)
Stimulusproduceschange invariable.
1
ReceptorReceptor
detects change.
Stimulusproduceschange invariable.
1
2
VARIABLE (in homeostasis)
Input: Information sent along afferent pathway to control center.
Receptor
ControlCenter
Receptor
detects change.
Afferent
pathway
VARIABLE (in homeostasis)
Stimulusproduceschange invariable.
1
3
2
Input: Information sent along afferent pathway to control center.
Receptor
ControlCenter
EffectorReceptor
detects change.
Afferent
pathway
Efferent
pathway
VARIABLE (in homeostasis)
Stimulusproduceschange invariable.
Output: Information sent along efferent pathway to effector.
1
3 4
2
Input: Information sent along afferent pathway to control center.
Receptor
ControlCenter
EffectorReceptor
detects change.
Afferent
pathway
Efferent
pathway
VARIABLE (in homeostasis)
Stimulusproduceschange invariable.
Output: Information sent along efferent pathway to effector.
Responseof effector feedsback to reducethe effect ofstimulus andreturns variableto homeostatic level.
1
3 4
52
Maintaining HomeostasisThe body communicates through neural and hormonal
control systems
ReceptorResponds to changes in the environment (stimuli)
Sends information to control center
Control CenterDetermines set point
Analyzes information
Determines
appropriate response
EffectorProvides a means for
response to the
stimulus
Negative feedbackIncludes most homeostatic control mechanisms
Shuts off the original stimulus, or reduces its intensity
Works like a household thermostat
Positive feedbackIncreases the original stimulus to push the variable farther
In the body this only occurs in blood clotting and during the
birth of a baby
The Language of Anatomy
Special terminology is used to
prevent misunderstanding
Exact terms are used for
Position
Direction
Regions
Structures
Regional Terms
Anterior body landmarks
Cervical
Umbilical
Pubic (genital)
PelvicInguinal(groin)
KEY:
Deltoid
Digital
Lower limb
Coxal (hip)
Patellar
Fibular
Pedal (foot)
Digital
Upper limb
Acromial
Brachial (arm)
Antecubital
Antebrachial
Carpal (wrist)
Manus (hand)
Crural (leg)
Tarsal (ankle)
Femoral (thigh)
CephalicFrontalOrbitalNasal BuccalOral
Mental
Thorax
Abdomen
Back (Dorsum)
Thoracic
Sternal
Axillary
Abdominal
(forearm)
Posterior body landmarks
Gluteal
Sacral
Lumbar
Vertebral
Back (dorsal)
Scapular
Cervical
CephalicOccipital (back
of head)Acromial
Brachial (arm)
Olecranal
Antebrachial
Manus (hand)
Digital
Femoral (thigh)
Popliteal
Sural (calf)
Fibular
Pedal (foot)
Calcaneal
Plantar
Upper limb
KEY:
Thorax
Abdomen
Back (Dorsum)
(forearm)
Superior (cranial or cephalad): toward the head
end or upper part of a structure or the body; above
Inferior (caudal): away from the head end or
toward the lower part of a structure or the body; below
Ventral (anterior): toward or at the front of the body;
in front of
Dorsal (posterior): 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
Intermediate: between a more medial and
a more lateral structure
Medial
Lateral
Intermediate
Proximal: close to the origin of the body part
or point of attachment to a limb to the body trunk
Distal: farther from the origin of a body part or
the point of attachment of a limb to the body trunk
Proximal
Distal
Superficial: toward or at the body surface
Deep: away from the body surface; more internal
Body Planes and Sections
A sagittal section divides the body (or organ) into left and right parts.
A median, or midsagittal, section divides the body (or organ) into equal left and right parts.
A frontal, or coronal, section divides the body (or organ) into anterior and posterior parts.
A transverse, or cross, section divides the body (or organ) into superior and inferior parts.
(a) Median (midsagittal) (b) Frontal (coronal) plane (c) Transverse plane
Body Cavities
Dorsal body cavity
Cranial cavity houses the brain
Spinal cavity houses the spinal cord
Ventral body cavity
Thoracic cavity houses heart, lungs, and others
Abdominopelvic cavity houses digestive system
and most urinary system organs
Cranial cavity
Spinal cavity
Thoraciccavity
Diaphragm
Abdominalcavity
Pelviccavity
Ab
do
min
op
elv
icc
avit
y
KEY:
Dorsal body cavity Ventral body cavity
Right upper
quadrant
(RUQ)
Right lower
quadrant
(RLQ)
Left upper
quadrant
(LUQ)
Left lower
quadrant
(LLQ)
Righthypo-
chondriacregion
Epigastricregion
Rightlumbarregion
Umbilicalregion
Right iliac(inguinal)
region
Hypogastric(pubic)region
Left iliac(inguinal)
region
Leftlumbarregion
Lefthypo-
chondriacregion
(a) Nine regions delineated by four planes (b) Anterior view of the nine regionsshowing the superficial organs
Liver
Gallbladder
Ascendingcolon of largeintestine
Small intestine
Cecum
Appendix
Diaphragm
Stomach
Transversecolon of largeintestine
Descendingcolon of largeintestine
Initial part ofsigmoid colon
Urinarybladder