Introduction & Overview Chapter 1 The Human Body Introduction & Overview Chapter 1

Anatomy ana = apart tomy = to cut Subdivision of biology; describes how our bodies are put together. The study of the structure and shape of the body and body parts and their relationships to one another Gross anatomy – study of large body structures Microscopic anatomy – study of small body structures using a microscope or magnifying instrument.

Specialties of Anatomy Gross Anatomy (large anatomy) Examines large, physical structures Surface anatomy (exterior features) Regional anatomy (body areas) Systemic anatomy (groups of organs working together) Developmental anatomy (from egg to maturity) Embryology (before birth) Specialties of Anatomy

Microscopic Anatomy Examines cells and molecules Cytology (cells and their structures) Histology (tissues and their structures) Pathological anatomy diseases Radiographic anatomy internal structures using special visualization techniques

Physiology Physio = nature ology = study of Subdivision of biology; describes how body parts work together. The study of how the body and its parts work or function. Example: cardiac physiology studies the function of the heart, which acts as a muscular pump to keep blood flowing throughout the body.

Relationship between Anatomy & Physiology All the parts of the body form a well organized unit, and each of those parts has a job to do to make the body operate as a whole. The structure of a part determines what functions can take place. Example: lungs are not muscular chambers like the heart and cannot pump blood through the body. The walls of the lungs are very thin; this allows gases to be exchanged and provide oxygen to the body.

Organizational Levels The body structure has many levels. The simplest level begins with the chemical level. We start with atoms (tiny building blocks of matter) which combine to form molecules such as sugar, water and proteins. Molecules (combination of atoms) in turn, come together in specific ways to form cells (smallest units of all living things).

Once we have cells, we are in the cellular level. Cells come in all sizes, and shapes which determine their particular functions in the body. The simplest living creatures are composed of only a single cell. In complex organisms like plants and animals the cells come together at the tissue level. Tissues consists of groups of similar cells that share a similar function. There are 4 basic tissue types: epithelial, connective, muscular, and neural

From the tissue level we move up into the organ level. An organ is a structure that is composed of 2 or more tissue types and performs a specific function for the body. Organs may contain more than one kind tissue; this allows the organ to be able to perform extremely complex functions. All of the body’s organs are grouped together into an organ system, which is the next level. An organ system is a group of organs that work together to accomplish a common purpose. Small intestine contains all 4 types of tissues.

Levels Of Structural Organization

Organ Systems

Organ Systems Integumentary (skin) Skeletal Muscular Nervous The living body is composed of 11 organ systems: Integumentary (skin) Skeletal Muscular Nervous Cardiovascular Lymphatic Endocrine (hormones) Respiratory Digestive Urinary Reproductive

Maintaining Life In order to maintain life an organism must be able to maintain its boundaries so that its “insides” remain distinct (separate) from its “outside”. In order to do this the organism also needs to move, respond to stimuli, digest nutrients, excrete wastes, carry on metabolism, reproduce itself and grow. Survival needs include: food, oxygen, water, appropriate temperature, and normal pressure. No water: 8-14 days, No food: 4-6weeks, Air/Oxygen: 3-5 minutes for brain death; people have been drowned in very cold water and recovered after hours of no oxygen, the rapid loss of body temperature saved the brain tissue by slowing brain cell deterioration.

Homeostasis Body functions interact to maintain homeostasis – a level of relatively stable internal environment within the organism’s body. Homeostasis is necessary for survival and good health. In order to maintain homeostasis, communication within the body is essential. The body does this through 3 elements: receptors, control center, and effectors.

Homeostasis Purpose: keeps system in check 3 parts: Receptor Receives a stimulus Control Center Processes info, sends out commands Effector A cell or organ that responds to the stimulus Homeostasis

Use the example of a thermostat What is the receptor? What is the control center? What is the effector?

Use the example of a thermostat What is the receptor? Thermometer (internal or external) What is the control center? The thermostat What is the effector? The air conditioner which turns on and off to maintain the desired temperature.

Elements of a Homeostatic Control System The results of the effectors’ response is then fed back to influence the stimulus (which produced the initial change). It does so, by depressing it /shutting it down(negative feedback) or enhancing it so the reaction continues at an even faster rate. Negative feedback mechanism example – home heating system. Thermostat is the receptor with triggers the control switch for the unit (control center); the heating system (the effector), turns on heat when temperature drops below a preset temperature.

Negative feedback Primary mechanism of homeostatic regulation The response of the effector negates the stimulus Ex.: body temperature, blood pressure, blood glucose levels nervous & endocrine systems Negative feedback

Positive Feedback The response of the effector reinforces the stimulus Ex.: blood clotting, childbirth Positive Feedback

No homeostasis = disease or death

Body erect Palms forward Thumbs point away Anatomical Position

Language of Anatomy The terms we will be using in class are relative and start off with the assumption that the body is the anatomical position – body is upright with palms facing forward. The terms are divided into 2 groups: anterior – parts of body facing forward posterior - parts of body facing backwards

Used to explain exactly where one body part is in relation to another Dorsal vs. ventral Distal vs. proximal Medial vs. lateral Superior vs. inferior Directional Terms

Superficial-affecting, or being on or near the surface Deep- situated far beneath the surface; not superficial. Superior- towards the top (above) Inferior- towards the bottom (below)

Anatomical Positions of the Body

Regional Terms Axial region: head, neck, trunk Appendicular region: upper & lower limbs Regional Terms

Regional Terms

Regional Terms

Anatomical Planes & Sections of the Body

Sagittal Plane Separates body into left and right halves midsagittal – in the middle Sagittal Plane

Frontal Plane Vertical plane Separates the body into anterior & posterior parts Frontal Plane

Transverse Plane Horizontal Divides body into superior & inferior parts Transverse Plane

Body Cavities There are 2 cavities that provide different degrees of protection to the organs within them. These cavities differ in their purpose, as well as the manner in which they developed (as an embryo). They also differ in their lining membranes. The 2 major set of internal cavities are: dorsal body cavity ventral body cavity

Dorsal Body Cavity CNS, 2 subdivisions: Cranial cavity within the skull houses the brain Spinal cavity within the vertebral column houses the spinal cord Dorsal Body Cavity

Ventral Body Cavity Anterior, larger, houses the organs Thoracic cavity surrounds the lungs (pleural cavity) heart (pericardial cavity) Abdominopelvic cavity 9 regions 4 quadrants Ventral Body Cavity

Body Cavities LateralView

Body Cavities Anterior View Superior mediastinum is the area between the lungs

Abdominopelvic Regions

Internal organs