Introduction to Anatomy The Human BodyAn Orientation Anatomy

Introduction to Anatomy

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 Figure 14. 1

Anatomy—Levels of Study �Microscopic Anatomy �Very small structures �Can only be viewed with a microscope Figure 14. 4 c–d

Organization of the Human Body �Atoms �Molecules �Macromolecules �Organelles �Cells �Tissues �Organ Systems �Organism

Organ Systems

Organ Systems �Integumentary �Cardiovascular �Skeletal �Lymphatic �Muscular �Digestive �Nervous �Respiratory �Endocrine �Urinary �Reproductive (male & female)

Organ Systems (5: 00)

Organ System Overview �Integumentary �Forms the external body covering �Protects deeper tissue from injury �Helps regulate body temperature �Location of cutaneous nerve receptors Figure 1. 2 a

Organ System Overview �Skeletal �Protects and supports body organs �Provides muscle attachment for movement �Site of blood cell formation �Stores minerals Figure 1. 2 b

Organ System Overview �Muscular �Produces movement �Maintains posture �Produces heat Figure 1. 2 c

Organ System Overview �Nervous �Fast-acting control system �Responds to internal and external change �Activates muscles and glands Figure 1. 2 d

Organ System Overview �Endocrine �Secretes regulatory hormones �Growth �Reproduction �Metabolism Figure 1. 2 e

Organ System Overview �Cardiovascular �Transports materials in body via blood pumped by heart �Oxygen �Carbon dioxide �Nutrients �Wastes Figure 1. 2 f

Organ System Overview �Lymphatic �Returns fluids to blood vessels �Cleanses the blood �Involved in immunity Figure 1. 2 g

Organ System Overview �Respiratory �Keeps blood supplied with oxygen �Removes carbon dioxide Figure 1. 2 h

Organ System Overview �Digestive �Breaks down food �Allows for nutrient absorption into blood �Eliminates indigestible material Figure 1. 2 i

Organ System Overview �Urinary �Eliminates nitrogenous wastes �Maintains acid-base balance �Regulates water and electrolytes Figure 1. 2 j

Organ System Overview �Reproductive �Produces offspring Figure 1. 2 k–l

Necessary Life Functions �Maintain boundaries �Movement �Locomotion �Movement of substances �Responsiveness �Ability to sense changes and react �Break-down and absorption of nutrients

Necessary Life Functions �Metabolism—chemical reactions within the body �Produces energy �Makes body structures �Excretion �Eliminates waste from metabolic reactions

Necessary Life Functions �Reproduction �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– 80% of body weight �Provides for metabolic reaction �Stable body temperature �Atmospheric pressure �Must be appropriate

Interrelationships Among Body Systems Figure 1. 3

Homeostasis �Homeostasis—maintenance of a stable internal environment �A dynamic state of equilibrium �Homeostasis is necessary for normal body functioning and to sustain life �Homeostatic imbalance �A disturbance in homeostasis resulting in disease

Input: Information sent along afferent pathway to Control center Output: Information sent along efferent pathway to activate Effector Receptor (sensor) Change detected by receptor Stimulus: Produces change in variable Imb ala nce Variable (in homeostasis) Imb ala nce Response of effector feeds back to influence magnitude of stimulus and returns variable to homeostasis Figure 1. 4

Variable (in homeostasis) Figure 1. 4, step 1 a

Stimulus: Produces change in variable Imb ala nce Variable (in homeostasis) Imb ala nce Figure 1. 4, step 1 b

Receptor (sensor) Change detected by receptor Stimulus: Produces change in variable Imb ala nce Variable (in homeostasis) Imb ala nce Figure 1. 4, step 2

Input: Information sent along afferent pathway to Control center Receptor (sensor) Change detected by receptor Stimulus: Produces change in variable Imb ala nce Variable (in homeostasis) Imb ala nce Figure 1. 4, step 3

Input: Information sent along afferent pathway to Control center Output: Information sent along efferent pathway to activate Effector Receptor (sensor) Change detected by receptor Stimulus: Produces change in variable Imb ala nce Variable (in homeostasis) Imb ala nce Figure 1. 4, step 4

Input: Information sent along afferent pathway to Control center Output: Information sent along efferent pathway to activate Effector Receptor (sensor) Change detected by receptor Stimulus: Produces change in variable Imb ala nce Variable (in homeostasis) Imb ala nce Response of effector feeds back to influence magnitude of stimulus and returns variable to 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 a muscle contracting to move the arm a muscle squeezing saliva from the salivary gland a gland releasing a hormone into the blood

Homeostasis-The body in balance �The purpose of organ systems is to provide an organism with a stable internal environment. �Injury and illness disrupt this internal balance. �The body remains in homeostasis by a system called negative feedback. �The negative feedback loop is the MOST common. �Human and Animal medicine attempts to regain homeostasis within particular systems which cannot regain balance due to illness and injury.

Negative Feedback

Positive Feedback Loops �A positive feedback mechanism is the exact opposite of a negative feedback mechanism. With negative feedback, the output reduces the original effect of the stimulus. In a positive feedback system, the output enhances the original stimulus �Examples: Child birth (production of Oxytocin to cause contractions) and blood clotting �Just remember that positive feedback mechanisms enhance the original stimulus and negative feedback mechanisms inhibit it.

The Language of Anatomy �Special terminology is used to prevent misunderstanding �Exact terms are used for �Position �Direction �Regions �Structures �Anatomical Position – a standard body position for studying the body—standing erect with arms at your side and palms facing ventral

Surface Regions

Anatomical Terms (2: 37)

Directional Terms Table 1. 1 (1 of 3)

Directional Terms Table 1. 1 (2 of 3)

Directional Terms Table 1. 1 (3 of 3)

Relative Position �Superior �Proximal �Inferior �Distal �Ventral �Superficial �Dorsal �Deep �Medial �Lateral

Body Planes and Sections �A median (sagittal) section divides the body (or organ) into equal left and right parts �A frontal (coronal) section divides the body (or organ) into anterior and posterior parts �A transverse (cross) section divides the body (or organ) into superior and inferior parts

Body Planes

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

Body Cavities (pleural cavity)

Body Cavities-continued

Abdominopelvic Major Organs Figure 1. 8 c

Membranes and Cavities �Serous membranes line the walls of cavities and cover organs. �These membranes secrete serous fluid which lubricate the free surfaces.

Quadrants

9 Abdominal Regions