A & P - Chapter 1: The Human Body - An Orientation
Anatomy - the study of the structure and shape of the body and body parts and their relationships to one
another
Physiology - the study of how the body and its parts work or function
Anatomy and Physiology are always related; the body is made of parts that form a well-organized unit
and each of the parts have a specific job to do to make the body operate as a whole
* Structure determines what functions can take place
Levels of Structural Organization:
 Chemical Level - atoms (the smallest units of matter) combine to form molecules
 Cellular Level - cells (the smallest units of life); come in a wide variety of size and shapes
that reflect their particular function
 Tissue Level - tissues (consist of similar types of cells that have a common function); 4 basic
tissue types
1. Epithelial – covers and protects
2. Connective – used for support
3. Muscular – movement
4. Nervous – coordinates body activities
 Organ Level - organs (made up of 2 or more types of tissues that perform a specific function);
extremely complex functions become possible
 Organ System Level - organ systems (consist of different organs that work closely together to
accomplish a common purpose); 11 organ systems
 Organismal Level - organism is made up of many organ systems that work together as a wellorganized unit to promote the well-being of the entire body
Necessary Life Functions
Maintaining Boundaries – cell membranes and tissues
Metabolism – sum of all chemical reactions within an organism
Movement – self initiated change in position, motion of internal parts
Responsiveness – (or irritability) – ability to sense changes within, or around the organism and
react to them
Digestion – chemically changing (breaking down) food substances, and getting rid of wastes
Absorption – passage of digested products (food substances) through membranes and into body
fluids
Excretion – removal of wastes
Reproduction - parents produce offspring / producing new individuals
Growth - increase in body size
Respiration – obtaining oxygen (O2), using it to release energy from food substances, and getting
rid of wastes
Circulation – movement of substances throughout the body
Assimilation - Changing absorbed substances into chemically different substances
5 Survival Needs
Nutrients – foods
Oxygen – 20% of air we breathe
Water – 60 to 80% of body weight
Body temperature – must be maintained around 98.6ºF
Atmospheric pressure – must have; cannot survive without
Homeostasis - the body’s ability to maintain relatively stable internal conditions in a continuously
changing external environment – hypothalamus: example of our thermostat
- The human body is in homeostasis when its needs are being adequately met and it is functioning
smoothly
Homeostatic Imbalance – over time our body does this and our body doesn’t function like when we were
younger
Human Organ Systems:
 Integumentary System - forms the external body covering; protects deeper tissue
from injury; synthesizes Vitamin D; location of cutaneous receptors (pain, pressure,
etc.), sweat and oil glands – {waterproofs the body and cushions/temperature,
pressure, pain receptors, and sweat/oil glands}
o Skin
○ Cutaneous receptors
o Hair
○ Sweat and oil glands

Skeletal System - protects and supports body organs; provides a framework the
muscles use to cause movement; blood cells are formed within bones; stores
minerals – {supports the body and provides a framework that the skeletal muscles
can use to cause movement, also has a protective function)
o Hematopoiesis (formation of blood cells)
o Bones
○ Ligaments
o Cartilage
○ Joints
o Tendons
○ Blood Cells (Red)

Muscular System - allows manipulation of the environment; locomotion and facial
expression; maintains posture; produces heat – {to contract, or shorten, allows
manipulation of environment, locomotion, and facial expression; maintains posture,
produces heat/skeletal muscles – striated voluntary}
o Cardiac muscles
o Smooth muscles
o Skeletal muscles

Nervous System - fast-acting control system of the body; responds to internal and
external changes by activating appropriate muscles and glands – {fast-acting control
system of the body, responds to internal and external changes by activating appropriate
muscles and glands/brain, spinal cord, nerves, and sensory receptors}
o Brain
o Spinal cord
o Nerves
o Sensory receptors

Endocrine System - glands secrete hormones that regulate processes such as growth,
reproduction, and nutrient use (metabolism) by body cells – {gland secrete hormones
that regulate processes such as growth, reproduction, and nutrient use by body cells}
o Pituitary
○ Pineal
o Thyroid
○ Mammary Glands
o Parathyroid
○ Ovaries-female
o Adrenals
○ Testes-male
o Thymus
○ Pancreas

Cardiovascular System - blood vessels transport blood which carries oxygen, carbon
dioxide, nutrients, wastes, etc.; the heart pumps blood – {using blood as transporting
fluid, carries oxygen, nutrients, hormones and other substances to and from the tissue
cells where exchanges are made/heart, blood vessels, capillaries}
o Heart
o Blood vessels
o Arteries
o Veins
o Capillaries

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 – {vessels return fluid leaked from the blood to the blood vessels so the blood
can be kept continuously circulating through the body}
o White blood cells
○ Thymus
o Lymphatic vessels
○ Spleen
o Lymph nodes
○ Tonsils

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 – {keep the body constantly supplied with oxygen and to remove carbon dioxide}
o Nasal passages
○ Lungs
○ Alveoli
o Pharynx
○ Bronchi
o Larynx
○ Trachea

Digestive System - breaks down food into absorbable units that enter the blood for
distribution of body cells; indigestible food stuffs are eliminated as feces – {break
down food and deliver the products to the blood for dispersal to body cells,
undigested food that remains leave the body through feces}
o Oral cavity/Mouth
○ Large intestines
o Esophagus
○ Rectum
o Stomach
○ Liver
o Small intestines
○ Pancreas

Urinary System - eliminates nitrogenous wastes from the body; regulates water,
electrolyte, and acid-base balance of the blood – {removes nitrogen-containing
wastes from the blood and flushes them from the body in urine (excretory})
o Kidneys
o Ureters
o Bladder
o Urethra

Reproductive System - overall function is production of offspring; {exists primarily to produce offspring, sperm produced by testes of male,
ovary female produces egg or ova}
o Male - testes produce sperm and male sex hormone; ducts and
glands aid in delivery of viable sperm to the female reproductive
tract
 Testes
■ Penis
 Accessory ducts
■ Accessory glands
o Female - 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
 Mammary Glands
■ Uterus
 Vagina
■ Fallopian tubes
 Vulva
■ Ovaries
Anatomical Position, Regions, and Cavities
• Position terms:
– explain how a patient should be positioned for a procedure
• Directional terms describe:
– the relative location of different body features
– the ways the body can be viewed along imaginary lines
• Body region terms:
– create a map of the body locations
– describe the location of pain or injury
• Body cavity terms:
– create a map of the body structures
– help healthcare workers communicate accurately and effectively
Anatomical Position
Anatomical/Supine – (anterior) – front side, hands facing forward
Prone – (posterior) – back side, palms are face down
Directional Terms
Superior (cranial or cephalad) – toward head or upper part
Inferior (caudal) – lower part
Anterior (ventral) – stomach side
Posterior (dorsal) – backside
Medial – towards middle line
Lateral – side
Intermediate – medial
Proximal – lies close to main part of body
Distal – away from main part of body
Superficial – surface
Deep – away from body surface
Parietal – outer layer or wall
Visceral – covering of an organ
Body Planes and Sections
 Section - cut that is made through the body wall or organ along an imaginary line
 Plane - an imaginary line through the body or organ
* Sagittal/Median - also called midsagittal; a
lengthwise (longitudinal) cut made along the body that divides
the body into right and left parts; {runs vertical (divides the
body into right and left segments)}
* Midsagittal- a lengthwise (longitudinal) cut made
along the body; each side in equal in size – (runs vertical)
* Frontal - also called coronal; a cut made along a
lengthwise plane that divides the body/organ into anterior
(front/stomach side) and posterior (back side) parts
* Transverse - also called a cross-section; a cut made
along a horizontal plane, dividing the body/organ into superior
(upper) and inferior (lower) parts
Body Cavities


Dorsal Body Cavity – found within the skull and vertebral column
Cranial Cavity – brain
Spinal Cavity – spinal cord
Ventral Body Cavity – largest
Thoracic Cavity – (superior) consists of the lungs, esophagus, heart and major
blood vessels
Diaphragm – divides the cavity
Abdominopelvic Cavity – (inferior) consists of digestive, urinary, and
reproductive organs
Abdominal Cavity – digestive organs, kidneys, and spleen
Pelvic Cavity – contains urinary bladder, rectum, and reproductive organs