Chapter 1

The Human Body: An Orientation

Health & Anatomy Mrs. Gunderson

Overview of Anatomy and Physiology

l Anatomy – the study of the structure of body parts and their relationships to one another –  Gross or macroscopic = large & easily

observable –  Microscopic = very small –  Derived from the Greek words = cut (tomy)

apart (ana)

l Physiology – the study of the function of the body and its parts

Levels of Structural Organization

l  Chemical – atoms combined to form molecules (simplest level)

l  Cellular – cells are made of molecules and are the smallest units of all living things

l  Tissue – consists of similar types of cells l  Organ – made up of 2 or more tissue types l  Organ system – consists of different organs that work

closely together l  Organismal – made up of the organ systems (highest

level)

Figure 1.1

Necessary Life Functions I

l Maintaining boundaries – the internal environment remains distinct from the external –  Cellular level – accomplished by plasma membranes –  Organismal level – accomplished by the skin

l Movement – locomotion, propulsion (peristalsis), and contractility

l Responsiveness – ability to sense changes in the environment and respond to them

l Digestion – breakdown of ingested foods

Necessary Life Functions II l Metabolism – all the chemical reactions that

occur in the body l Excretion – removal of wastes from the body l Reproduction – cellular and organismal levels

–  Cellular – an original cell divides and produces two identical daughter cells

–  Organismal – sperm and egg unite to make a whole new person

l Growth – increase in size of a body part or of the organism

Survival Needs

l  Nutrients – chemical substances used for energy and cell building

l  Oxygen – needed for metabolic reactions l  Water – provides the necessary environment for

chemical reactions l  Maintaining normal body temperature – necessary for

chemical reactions to occur at life-sustaining rates l  Atmospheric pressure – required for proper breathing

and gas exchange in the lungs

Homeostasis

l  Homeostasis is the ability to maintain a relatively stable internal environment in an ever-changing outside world

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

l  Chemical, thermal, and neural factors interact to maintain homeostasis

Body Systems: Integumentary System- Function: Waterproof, external covering, protection, cushions, excretes salts, regulates body temp. Parts: external coverings (skin), including nails & hair. Skeletal System- Function: Provides framework that muscles use for movement, supports the body & stores minerals. Parts: bones, cartilage, ligaments and joints.

Nervous System- Function: Fastest Acting System- respond to stimuli, irritants. Detect these changes and send messages. Parts: Brain, spinal cord, nerves and sensory receptors. Endocrine System- Function: Produce chemicals molecules called hormones and release into the blood. To target organs Parts: Glands located throughout the body.

Cardiovascular System- Function: Carries oxygen, hormones & nutrients. Parts: Heart and blood vessels. Lymphatic System- Function: complement the Cardio. Helps circulates fluids leaked from the blood. Parts: Lymphatic Vessels, nodes, spleen and tonsils.

Respiratory System- Function: Keep body supplied with oxygen and to remove carbon dioxide. Parts: nasal passages, pharynx, larynx, trachea, bronchi, and lungs. Digestive System- Function: Break down food and deliver products to the blood for dispersal to body cells. Parts: oral cavity, esophagus, stomach, small & Large Intestines, & rectum.

Urinary System- Function: removes nitrogenous waste from blood and flushes them from the body. Parts: kidneys, ureters, bladder and urethra. Muscular System – Function: Contract, movement occurs. Parts: Cardiac, smooth and skeletal muscles.

Stop Day 1 NOTES!

Reproductive System- Function: produce offspring and supply the cell responsible for reproduction. Parts: Testes, ovaries, vas deferens, fallopian tubes, uterus, urethra, etc.

Anatomical Position l Body erect, feet

slightly apart, palms facing forward, thumbs point away from the body

Figure 1.7a

Directional Terms l  Superior and inferior – toward

and away from the head.

l  Anterior and posterior – toward the front and back of the body

l  Medial, lateral, and intermediate – toward the midline, away from the midline, and between a more medial and lateral structure

Directional Terms l Proximal and distal –

closer to and farther from the origin of the body

l Superficial and deep – toward and away from the body surface

Directional Terms

Table 1.1

Directional Terms

Table 1.1 (continued)

Directional Terms

Table 1.1 (continued)

Body Planes l  Sagittal or medial – divides the body into right and left

parts l  Frontal or coronal – divides the body into anterior and

posterior parts l  Transverse or horizontal (cross section) – divides the

body into superior and inferior parts l  Oblique section – cuts made diagonally

Body Cavities l Dorsal cavity protects the

nervous system, and is divided into two subdivisions –  Cranial cavity is within the skull

and encases the brain –  Vertebral cavity runs within the

vertebral column and encases the spinal cord

l Ventral cavity houses the internal organs (viscera), and is divided into two subdivisions: thoracic and abdominopelvic

Body Cavities l  Thoracic cavity is subdivided into

pleural cavities, the mediastinum, and the pericardial cavity –  Pleural cavities – each houses a lung –  Mediastinum – contains the pericardial

cavity, and surrounds the remaining thoracic organs

–  Pericardial – encloses the heart

Body Cavities l The Abdominopelvic cavity is separated from the superior thoracic cavity by the dome-shaped diaphragm

l  It is composed of two subdivisions –  Abdominal cavity –

contains the stomach, intestines, spleen, liver, & other organs

–  Pelvic cavity – lies within the pelvis and contains the bladder, reproductive organs and rectum

Ventral Body Cavity Membranes

l  Parietal serosa covering the body walls

l  Visceral serosa covering the internal organs

l  Serous fluid separates the serosae

Figure 1.10

Abdominopelvic Regions

l  Umbilical l  Epigastric l  Hypogastric l  Right and left iliac or

inguinal l  Right and left lumbar l  Right and left

hypochondriac

Figure 1.11a

Abdominopelvic Regions

Figure 1.11b

Abdominopelvic Quadrants

l Right upper l Left upper l Right lower l Left lower

Figure 1.12