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