Chapter 1Human Body

An Orientation

What is Anatomy and Physiology

• Anatomy: The study of the structures of body parts and their relationship to one another.

• Subdivided and studied as– Gross or macroscopic–Microscopic–Developmental

• Physiology: The study of the function of the body’s structural machinery.

Gross or Macroscopic Anatomy

• Gross anatomy is studied using both invasive and noninvasive methods with the goal of obtaining information about the macroscopic structure and organization of organs and organ systems. It can be studied with the naked eye.

• Regional: all structures are in one part of the body (abdomen, leg or hand)

• Systemic: gross anatomy of the body studied by systems.

• Surface: study of internal structures as they relate to overlying skin.

Gross or Macroscopic Anatomy

Regional Anatomy

Systemic Anatomy

Surface Anatomy

Microscopic Anatomy

• Microscopic anatomy is the study of minute anatomical structures assisted with microscopes

• Subdivided into – Cytology: Study of cells–Histology: Study of tissue

Microscopic Anatomy

Cytology

Histology

Developmental Anatomy• Traces structural changes

throughout life• Embryology: the study of

developmental changes of the body before birth.

Specialized Branches of Anatomy

• Pathological anatomy: study of structural changes caused by disease.

• Radiographic anatomy: study of internal structures visualized by specialized scanning procedures such as X-ray, MRI, and CT scans.

• Molecular Biology: study of anatomical structures at a subcellular level.

Pathological anatomy:

Radiographic anatomy:

Molecular Biology

Physiology

• Considers the operation of specific organ systems.

• Renal (Kidneys)• Neurophysiology (Nerves)• Cardiovascular ( Heart and blood

vessels)• Focuses on the function of the body, often at

the cellular or molecular level.

• Understanding physiology also requires a knowledge of physics, which explains

• Electrical currents• Blood pressure• The way muscles use bones for

movement

• Physiology just like anatomy has its own groups of specialization.

• Cell physiology: function of the cell• Special physiology: physiology of specific

organs• Systemic physiology: physiology of

systems• Pathological physiology: effects of diseases on

organs and system function.

Levels of Structural Organization

• Chemical: atoms combine to form molecules

• Cellular: cells are made of molecules• Tissue: consists of similar types of cells• Organ: made of different types of tissue• Organ system: consists of different

organs that work closely together.• Organism: made up of the organ systems

Levels of Structural Organization

Organ System Overview Integumentary System

• Form external body covering

• Composed of the skin, sweat glands, oil glands, hair and nails.

• Protects deep tissues from injury and synthesizes vitamin D

Skeletal System

• Composed of bone cartilage and ligaments

• Protects and supports body organs

• Provides framework for muscles

• Site of blood cell formation• Stores minerals

Muscular System• Composed of

muscles and tendons

• Allows ,manipulation of the environment, locomotion and facial expression

• Maintains posture• Produces heat

Nervous System

• Composed of the brain, spinal column, and nerves

• Is the fast – acting control system of the body• Responds to stimuli by activating muscles and

glands.• CNS: Central Nervous System• PNS: Peripheral Nervous System

Nervous System

CNS

PNS

Cardiovascular System

• Composed of the heart and blood vessels.

• The heart pumps blood• The blood vessels

transport blood throughout the body

Lymphatic System

• Composed of red bone marrow, thymus, spleen, lymph nodes, and lymphatic vessels

• Picks up fluid leaked from blood vessels and returns it to blood

• Disposes of debris in the lymphatic stream

• Houses white blood cells involved with immunity.

Respiratory System

• Composed of the nasal cavity, pharynx, trachea, bronchi, and lungs

• Keeps blood supplied with oxygen and removes carbon dioxide.

Digestive System

• Composed of the oral cavity (Mouth), esophagus, stomach, small intestine, large intestine, rectum, anus and liver

• Breaks down food into absorbable units that enter the blood

• Eliminates indigestible foodstuff as feces.

Urinary SystemRenal System

• Composed of kidneys, ureters, urinary bladder, and urethra

• Eliminates nitrogenous wastes from the body

• Regulates water and electrolyte, and pH balance of the blood

Male Reproductive System

• Composed of prostate gland, penis, testes, scrotum, and ductus deferens

• Main function to produce offspring

• Testes produce sperm and male sex hormones (testosterone, xy)

• Ducts and glands deliver sperm to the female reproductive tract.

Female Reproductive System

• Composed of mammary glands, ovaries, uterine tubes (fallopian tubes), uterus, and vagina

• Main function is to produce offspring• Ovaries produce eggs and female hormones (estrogen and

progesterone, XX) • Remaining structures serve as sites for fertilization and

development of the fetus• Mammary glands produce milk to nourish newborn

Organ Systems Interrelationships

• The integumentary system protects the body from the external environment.

• Digestive and respiratory systems, in contact with the external environment, take in nutrients and oxygen

• All organ systems within a body are dependent on one another.

• Nutrients and oxygen are distributed by the blood

• Metabolic wastes are eliminated by the urinary system and respiratory systems

Necessary Life Functions

• Maintaining boundaries – the internal environment remains distinct from the external environment

• Cellular Level : accomplished by plasma membrane

• Organism level: accomplished by the skin• Movement : locomotion, propulsion,

(peristalsis) and contractility

• Responsiveness: ability to sense change in the environment and respond to them

• Digestion: breakdown of ingested foodstuffs

• Metabolism: all the chemical reactions that occur in the body

• Excretion: removal of waste from the body• Reproduction : cellular and organismal

level

• Cellular: original cell divides and produces two identical daughter cells

• Organismal : sperm and egg unite to make whole new person.

• Growth : increase in size of a body part or of the organism

Survival Needs

• Nutrients : needed for energy and cell building

• Oxygen: necessary for metabolic reactions• Water: provides the necessary environment

for chemical reactions• Normal body temperature:

necessary for chemical reactions to occur at life – sustaining rates. 98oF or 37oC

• Atmospheric pressure: required for proper breathing and gas exchange in the lungs.

Homeostasis

• Homeostasis : ability to maintain a relatively stable internal environment in an ever – changing outside world

• The internal environment of the body is in a dynamic state of equilibrium

• Chemical, thermal, and neural factors interact to maintain homeostasis.

Homeostatic Control Mechanisms

• Variable produce a change in the body• The three interdependent components of

control mechanisms• Receptor: monitors the environments and

responds to the changes (stimuli)• Control center : determines the set

point at which the variable is maintained• Effector: provides the means to respond to

stimuli

Negative feedback

• In negative feedback systems, the input shuts off the original stimulus

• Example: Regulation of room temperature

Positive Feedback

• In positive feedback systems, the output enhances or exaggerates the original stimulus

• Example: Regulation of blood clotting

Homeostatic Imbalance

• Disturbance of homeostasis or the body’s normal equilibrium

• Overwhelming the usual negative feedback mechanism allows destructive positive feedback mechanisms to take over.

Anatomical Positions

• Surface anatomy is divided into regional terms anterior meaning “front” and posterior meaning “back”

• Body erect, feet slightly apart, palms facing forward, thumbs pointed away from the body.

Anterior

Posterior

Directional Terms

• Superior and inferior: toward or away from the head. Up or down from the head.

• Medial lateral and intermediate: toward the midline, away from the midline, and between a more medial and lateral structure.

• Proximal and distal: closer to and farther from the origin of the body part.

• Superficial or deep: toward and away from the surface

Directional Anatomical Terms

Anatomical Landmarks

Anterior Landmarks

• Abdominal: anterior body trunk inferior to ribs• Acromial: point of shoulder• Antecubital: anterior surface of elbow• Axillary: armpit• Brachial: arm• Buccal: cheek area• Carpal: wrist• Cervical: neck region

• Coxal: hip• Crural: leg• Digital: finger, toes• Femoral: thigh• Fibular: lateral part of leg• Inguinal area where thigh meets body trunk or

groin• Nasal: nose area

• Oral: mouth• Orbital: eye area• Patellar: anterior knee• Pelvic: area overlying the pelvis anteriorly• Pubic: genital region• Sternal: breastbone area• Tarsal: ankle region• Thoracic: chest• Umbilical: navel

Posterior Landmarks

• Calcaneal: heel of foot• Cephalic: head• Deltoid: curve of shoulder formed by large

deltoid muscles• Femoral: thigh• Gluteal: buttock• Lumbar: area of back between ribs and hips• Occipital: posterior surface of head

• Olecranal: posterior surface of elbow• Popliteal: posterior surface of the knee area• Sacral: area between the hips• Scapular: shoulder blade region• Sural: the posterior portion of the lower leg,

calf• Vertebral: area of the spine• Plantar: region or sole of foot

Body Planes

• Frontal section is a cut made along a lengthwise plane that divides the body into anterior and posterior parts this is also called the coronal plane or section.

• Sagittal is a cut made along the lengthwise or longitudinal plane of the body, dividing it into right and left parts. If the cut is made down the median plane of the body and the right and left parts are equal in size it is called midsagittal plane

Coronal or Frontal Plane

Sagittal Plane

Midsagittal Plane

Transverse Plane

• A transverse section is a cut made along a horizontal plane, dividing the body into superior and inferior parts.

• It is also called a cross section

Transverse Plane

Body Cavities

• Dorsal Body Cavity: Posterior has two subdivisions Cranial cavity which is the space inside the bony skull

• The second cavity is the Spinal Cavity which extends from the cranial cavity nearly to the end of the vertebral column

Dorsal Body Cavities

Ventral Body Cavity

• Ventral body cavity anterior is larger than the dorsal and subdivided.

• Thoracic Cavity: contains the heart lungs• Abdominal cavity: contains the

stomach, liver, and intestines.• Pelvic cavity: contains the reproductive

organs, bladder and rectum

Ventral Body Cavity

Body Regions

• There are nine body regions• Umbilical Region: center most region

deep and surrounding the naval• Epigastic Region: located superior to

the umbilicus. “epi” meaning above “gastric” meaning stomach

• Hypogastric (Pubic) Region: is inferior to umbilical region “hypo” means below

• Right and left iliac or inguinal region: lateral to the hypogastric region, iliac is the superior part of hip bone

• Right and left lumbar region: lie lateral to umbilical region “lumbus” meaning loin

• Right and left hypochondriac Region: flank the epigastric region and contain the lower rib “chondro” means cartilage

9 Body Regions

Quadrants of the body

• There are four quadrants of the body that are used to identify location of injury or pain.

• Right upper quadrant: RUQ• Left upper quadrant: LUQ• Right Lower quadrant: RLQ• Left lower quadrant: LLQ

Quadrants of the body