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The Human
Body: An
Orientation
THE HUMAN BODY—AN ORIENTATION
Anatomy

Study of the structure and shape of the body and its parts
Physiology

Study of how the body and its parts work or function
ANATOMY—LEVELS OF STUDY

Gross anatomy
Large structures
 Easily observable

Mouth (oral cavity)
Tongue
Stomach
Pancreas
(Spleen)
Liver
Gallbladder
Anus
Salivary glands
Pharynx
Esophagus
Small intestine
Parotid gland
Sublingual gland
Submandibular
gland
Duodenum
Jejunum
lleum
Transverse
colon
Descending
colon
Ascending
colon
Cecum
Sigmoid colon
Rectum
Appendix
Anal canal
Large intestine
Figure 14.1
ANATOMY—LEVELS OF STUDY

Microscopic anatomy
Structures cannot be seen with the naked eye
 Structures can only be viewed with a microscope

Gastric pits
Gastric pit
Mucous
neck cells
Gastric gland
Pyloric
sphincter
Surface
epithelium
Parietal cells
Gastric
glands
Chief cells
(c)
Figure 14.4c
Pepsinogen
HCl
Pepsin
Parietal cells
Chief cells
Enteroendocrine
cell
(d)
Figure 14.4d
Molecules
Smooth muscle cell
2 Cellular level
Cells are made
up of molecules.
Atoms
1 Chemical level
Atoms combine to
form molecules.
3 Tissue level
Tissues consist of
similar types of cells.
Smooth
muscle
tissue
Blood
vessels
Heart
Epithelial
tissue
Smooth
muscle
Blood
tissue
vessel
(organ)
Connective
tissue
4 Organ level
Organs are made up of
different types of tissues.
Cardio–
vascular
system
5 Organ system level
Organ systems consist of
different organs that work
together closely.
6 Organismal level
Human organisms are
made up of many organ
systems.
Figure 1.1
Figure 1.1, step 1
Figure 1.1, step 2
Figure 1.1, step 3
Figure 1.1, step 4
Figure 1.1, step 5
Figure 1.1, step 6
ORGAN SYSTEM OVERVIEW

Integumentary
Forms the external body covering
 Protects deeper tissue from injury
 Helps regulate body temperature
 Location of cutaneous nerve receptors

Skin
(a) Integumentary System
Forms the external body covering;
protects deeper tissue from injury;
synthesizes vitamin D; location of
cutaneous (pain, pressure, etc.)
receptors and sweat and oil glands.
Figure 1.2a
ORGAN SYSTEM OVERVIEW

Skeletal
Protects and supports body organs
 Provides muscle attachment for movement
 Site of blood cell formation
 Stores minerals

Cartilages
Joint
Bones
(b) Skeletal System
Protects and supports body
organs; provides a framework the
muscles use to cause movement;
blood cells are formed within
bones; stores minerals.
Figure 1.2b
ORGAN SYSTEM OVERVIEW

Muscular
Produces movement
 Maintains posture
 Produces heat

Skeletal
muscles
(c) Muscular System
Allows manipulation of the
environment, locomotion, and
facial expression; maintains
posture; produces heat.
Figure 1.2c
ORGAN SYSTEM OVERVIEW

Nervous
Fast-acting control system
 Responds to internal and external change
 Activates muscles and glands

Brain
Sensory
receptor
Spinal
cord
Nerves
(d) Nervous System
Fast-acting control system of the
body; responds to internal and
external changes by activating
appropriate muscles and glands.
Figure 1.2d
ORGAN SYSTEM OVERVIEW

Endocrine

Secretes regulatory hormones
Growth
 Reproduction
 Metabolism

Pineal gland
Pituitary gland
Thyroid gland
(parathyroid glands
on posterior aspect)
Thymus gland
Adrenal glands
Pancreas
Testis (male)
Ovary (female)
(e) Endocrine System
Glands secrete hormones that
regulate processes such as growth,
reproduction, and nutrient use by
body cells.
Figure 1.2e
ORGAN SYSTEM OVERVIEW

Cardiovascular

Transports materials in body via blood pumped by heart
Oxygen
 Carbon dioxide
 Nutrients
 Wastes

Heart
Blood
vessels
(f) Cardiovascular System
Blood vessels transport blood,
which carries oxygen, carbon
dioxide, nutrients, wastes, etc.;
the heart pumps blood.
Figure 1.2f
ORGAN SYSTEM OVERVIEW

Lymphatic
Returns fluids to blood vessels
 Cleanses the blood
 Involved in immunity

Thoracic
duct
Lymph
nodes
Lymphatic
vessels
(g) Lymphatic System
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.
Figure 1.2g
ORGAN SYSTEM OVERVIEW

Respiratory
Keeps blood supplied with oxygen
 Removes carbon dioxide

Nasal
cavity
Pharynx
Larynx
Trachea
Bronchus
Left lung
(h) Respiratory System
Keeps blood constantly supplied
with oxygen and removes carbon
dioxide; the gaseous exchanges
occur through the walls of the air
sacs of the lungs.
Figure 1.2h
ORGAN SYSTEM OVERVIEW

Digestive
Breaks down food
 Allows for nutrient absorption into blood
 Eliminates indigestible material as feces

Oral cavity
Esophagus
Stomach
Small
intestine
Large
intestine
Rectum
Anus
(i) Digestive System
Breaks food down into absorbable
units that enter the blood for
distribution to body cells;
indigestible foodstuffs are
eliminated as feces.
Figure 1.2i
ORGAN SYSTEM OVERVIEW

Urinary
Eliminates nitrogenous wastes
 Maintains acid-base balance
 Regulates water and electrolytes

Kidney
Ureter
Urinary
bladder
Urethra
(j) Urinary System
Eliminates nitrogen-containing
wastes from the body; regulates
water, electrolyte, and acid-base
balance of the blood.
Figure 1.2j
ORGAN SYSTEM OVERVIEW

Reproductive
Produces offspring
 Testes produce sperm and male hormone
 Ovaries produce eggs and female hormones

Seminal
vesicles
Prostate
gland
Mammary
glands
(in breasts)
Uterine
tube
Ovary
Uterus
Penis
Vas
deferens
Testis
Scrotum
(k) Male Reproductive System
Vagina
(l) Female Reproductive System
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.
Figure 1.2k–l
NECESSARY LIFE FUNCTIONS
Maintain boundaries
 Movement

Locomotion
 Movement of substances


Responsiveness


Ability to sense changes and react
Digestion

Breakdown and absorption of nutrients
NECESSARY LIFE FUNCTIONS

Metabolism—chemical reactions within the body
Break down complex molecules into smaller ones
 Build larger molecules from smaller ones
 Produces energy
 Regulated by hormones


Excretion
Eliminates waste from metabolic reactions
 Wastes may be removed in urine or feces

NECESSARY LIFE FUNCTIONS

Reproduction
Occurs on cellular level or organismal level
 Produces future generation


Growth

Increases cell size and number of cells
SURVIVAL NEEDS

Nutrients
Chemicals for energy and cell building
 Includes carbohydrates, proteins, lipids, vitamins, and
minerals


Oxygen

Required for chemical reactions
SURVIVAL NEEDS

Water
60 to 80 percent of body weight
 Most abundant chemical substance in the human body
 Is needed for metabolic reaction


Stable body temperature


37°C (98°F)
Atmospheric pressure

Must be appropriate for gas exchange
Digestive system
Takes in nutrients, breaks them
down, and eliminates unabsorbed
matter (feces)
Food
Respiratory system
Takes in oxygen and eliminates
carbon dioxide
O2
CO2
Cardiovascular system
Via the blood, distributes oxygen
and nutrients to all body cells and
delivers wastes and carbon
dioxide to disposal organs
Blood
Heart
Nutrients
CO2
O2
Urinary system
Eliminates
nitrogencontaining wastes
and excess ions
Interstitial fluid
Nutrients and wastes pass
between blood and cells
via the interstitial fluid
Feces
Integumentary system
Protects the body as a whole
from the external environment
Urine
Figure 1.3
HOMEOSTASIS

Homeostasis—maintenance of a stable internal
environment



A dynamic state of equilibrium
Necessary for normal body functioning and to sustain life
Homeostatic imbalance

A disturbance in homeostasis resulting in disease
3 Input: Information
sent along afferent
pathway to control
center.
2 Receptor
Receptor
Control
Center
Efferent
Afferent
pathway
pathway
sent along efferent
pathway to effector.
Effector
Response
of effector feeds
back to reduce
the effect of
stimulus and
returns variable
to homeostatic
level.
5
detects change.
1 Stimulus
produces
change in
variable.
4 Output: Information
VARIABLE (in homeostasis)
Figure 1.4
1 Stimulus
produces
change in
variable.
VARIABLE (in homeostasis)
Figure 1.4, step 1
2 Receptor
Receptor
detects change.
1 Stimulus
produces
change in
variable.
VARIABLE (in homeostasis)
Figure 1.4, step 2
3 Input: Information
sent along afferent
pathway to control
center.
2 Receptor
Receptor
Control
Center
Afferent
pathway
detects change.
1 Stimulus
produces
change in
variable.
VARIABLE (in homeostasis)
Figure 1.4, step 3
3 Input: Information
sent along afferent
pathway to control
center.
2 Receptor
Receptor
Control
Center
Efferent
Afferent
pathway
pathway
4 Output: Information
sent along efferent
pathway to effector.
Effector
detects change.
1 Stimulus
produces
change in
variable.
VARIABLE (in homeostasis)
Figure 1.4, step 4
3 Input: Information
sent along afferent
pathway to control
center.
2 Receptor
Receptor
Control
Center
Efferent
Afferent
pathway
pathway
sent along efferent
pathway to effector.
Effector
Response
of effector feeds
back to reduce
the effect of
stimulus and
returns variable
to homeostatic
level.
5
detects change.
1 Stimulus
produces
change in
variable.
4 Output: Information
VARIABLE (in homeostasis)
Figure 1.4, step 5
MAINTAINING HOMEOSTASIS

The body communicates through neural and hormonal
control systems

Receptor
Responds to changes in the environment (stimuli)
 Sends information to control center

MAINTAINING HOMEOSTASIS

Control center
Determines set point
 Analyzes information
 Determines appropriate response


Effector

Provides a means for response to the stimulus
FEEDBACK MECHANISMS

Negative feedback
Includes most homeostatic control mechanisms
 Shuts off the original stimulus, or reduces its intensity
 Works like a household thermostat

FEEDBACK MECHANISMS

Positive feedback
Increases 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
Cephalic
Frontal
Orbital
Nasal
Buccal
Oral
Mental
Cervical
Thoracic
Sternal
Axillary
Abdominal
Umbilical
Pelvic
Inguinal
(groin)
Upper limb
Acromial
Deltoid
Brachial (arm)
Antecubital
Antebrachial
(forearm)
Carpal (wrist)
Manus (hand)
Digital
Lower limb
Coxal (hip)
Femoral (thigh)
Patellar
Pubic (genital)
Crural (leg)
KEY:
Fibular
Pedal (foot)
Tarsal (ankle)
Thorax
Abdomen
Back (Dorsum)
Digital
(a) Anterior/Ventral
Figure 1.5a
REGIONAL TERMS

Posterior body landmarks
Cephalic
Occipital (back
of head)
Cervical
Upper limb
Acromial
Brachial (arm)
Olecranal
Antebrachial
(forearm)
Back (dorsal)
Scapular
Vertebral
Lumbar
Sacral
Manus (hand)
Digital
Gluteal
Femoral (thigh)
Popliteal
Sural (calf)
Fibular
KEY:
Thorax
Abdomen
Back (Dorsum)
Pedal (foot)
Calcaneal
Plantar
(b) Posterior/Dorsal
Figure 1.5b
DIRECTIONAL TERMS
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

Table 1.1
DIRECTIONAL TERMS
Ventral (anterior): toward or at the front of the
body; in front of
 Dorsal (posterior): toward or at the backside of the
body; behind

Table 1.1
DIRECTIONAL TERMS
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

Table 1.1
DIRECTIONAL TERMS
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

Table 1.1
DIRECTIONAL TERMS
Superficial: toward or at the body surface
 Deep: away from the body surface; more internal

Table 1.1
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)
Vertebral
column
Rectum
Intestines
(b) Frontal (coronal) plane
Right
lung Heart
Liver
Left
lung
Stomach Spleen
(c) Transverse plane
Liver Aorta
Spinal
Spleen
cord
Subcutaneous Stomach
fat layer
Figure 1.6
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
Thoracic
cavity
Spinal
cavity
Abdominal
cavity
Pelvic
cavity
KEY:
Dorsal body cavity
Abdominopelvic
cavity
Diaphragm
Ventral body cavity
Figure 1.7
Right upper
quadrant
(RUQ)
Left upper
quadrant
(LUQ)
Right lower
quadrant
(RLQ)
Left lower
quadrant
(LLQ)
Figure 1.8
Diaphragm
Liver
Stomach
Right
Left
Transverse
Gallbladder
hypohypoEpigastric
colon of large
chondriac
chondriac
region
intestine
Ascending
region
region
Descending
colon of large
Left
Right
colon of large
intestine
Umbilical
lumbar
lumbar
intestine
Small intestine
region
region
region
Initial part of
Cecum
Right iliac Hypogastric Left iliac
sigmoid colon
Appendix
(inguinal)
(pubic)
(inguinal)
Urinary
region
region
region
bladder
(b) Anterior view of the nine regions
(a) Nine regions delineated by four planes
showing the superficial organs
Figure 1.9a-b
CLASS RESPONSE
QUESTIONS
The Human Body: An
Orientation
ALL CHEMICAL REACTIONS THAT OCCUR IN THE
BODY ARE GROUPED UNDER
histology.
b) endocrinology.
c) metabolism.
d) cytology.
a)
ALL CHEMICAL REACTIONS THAT OCCUR IN THE
BODY ARE GROUPED UNDER
histology.
b) endocrinology.
c) metabolism.
d) cytology.
a)
THE POPLITEAL SURFACE IS THE
skull.
b) back of the knee.
c) front of the knee.
d) back of the heel.
a)
THE POPLITEAL SURFACE IS THE
skull.
b) back of the knee.
c) front of the knee.
d) back of the heel.
a)
THE SAGITTAL PLANE CUTS ONE INTO
anterior and posterior portions.
b) right and left portions.
c) equal right and left portions.
d) superior and inferior portions.
a)
THE SAGITTAL PLANE CUTS ONE INTO
anterior and posterior portions.
b) right and left portions.
c) equal right and left portions.
d) superior and inferior portions.
a)
THE REGION THAT INCLUDES MOST OF THE
RIBS IS THE
epigastric region.
b) hypochondriac region.
c) lumbar region.
d) iliac region.
a)
THE REGION THAT INCLUDES MOST OF THE
RIBS IS THE
epigastric region.
b) hypochondriac region.
c) lumbar region.
d) iliac region.
a)
GROSS ANATOMY IS THE STUDY OF BODY
STRUCTURES
too small to be seen with the naked eye.
b) that are large and easily observable.
c) belonging to the intestinal tract.
d) that are really disgusting.
a)
GROSS ANATOMY IS THE STUDY OF BODY
STRUCTURES
too small to be seen with the naked eye.
b) that are large and easily observable.
c) belonging to the intestinal tract.
d) that are really disgusting.
a)
THE INTEGUMENTARY SYSTEM IS
the body’s fastest acting control center.
b) responsible for producing hormones.
c) responsible for returning fluid to the circulatory
system.
d) the external covering of the body.
a)
THE INTEGUMENTARY SYSTEM IS
the body’s fastest acting control center.
b) responsible for producing hormones.
c) responsible for returning fluid to the circulatory
system.
d) the external covering of the body.
a)
PRODUCING BLOOD CELLS (HEMATOPOIESIS)
OCCURS IN THE ______ SYSTEM.
endocrine
b) integumentary
c) skeletal
d) cardiovascular
a)
PRODUCING BLOOD CELLS (HEMATOPOIESIS)
OCCURS IN THE ______ SYSTEM.
endocrine
b) integumentary
c) skeletal
d) cardiovascular
a)
MOST OFTEN, HOMEOSTASIS IS MAINTAINED BY
POSITIVE FEEDBACK.
True
False
MOST OFTEN, HOMEOSTASIS IS MAINTAINED BY
POSITIVE FEEDBACK.
True
False
ONCE A STIMULUS IS RECEIVED BY A
RECEPTOR, IT APPROACHES THE CONTROL
CENTER BY A(AN)
afferent pathway.
b) efferent pathway.
c) motor pathway.
d) reflex pathway.
a)
ONCE A STIMULUS IS RECEIVED BY A
RECEPTOR, IT APPROACHES THE CONTROL
CENTER BY A(AN)
afferent pathway.
b) efferent pathway.
c) motor pathway.
d) reflex pathway.
a)
THE ANTEBRACHIAL REGION CAN BE FOUND ON
THE
skull.
b) arm.
c) leg.
d) ankle.
a)
THE ANTEBRACHIAL REGION CAN BE FOUND ON
THE
skull.
b) arm.
c) leg.
d) ankle.
a)
THE ELBOW IS ____ TO THE WRIST.
inferior
b) lateral
c) proximal
d) distal
a)
THE ELBOW IS ____ TO THE WRIST.
inferior
b) lateral
c) proximal
d) distal
a)
THIS SYSTEM PICKS UP FLUID LEAKED FROM
BLOOD VESSELS AND RETURNS IT TO THE
BLOOD.
a) Integumentary
b) Endocrine
c) Cardiovascular
d) Lymphatic
THIS SYSTEM PICKS UP FLUID LEAKED FROM
BLOOD VESSELS AND RETURNS IT TO THE
BLOOD.
a) Integumentary
b) Endocrine
c) Cardiovascular
d) Lymphatic