The Human Body An Orientation

Overview of Anatomy and Physiology Anatomy – the study of the structure of body parts and their relationships to one another Gross or macroscopic Microscopic Developmental Physiology – the study of the function of the body’s structural machinery

Gross Anatomy Regional – all structures in one part of the body Regional – all structures in one part of the body the abdomen the abdomen leg leg Systemic – gross anatomy of the body studied by system Systemic – gross anatomy of the body studied by system Surface – study of internal structures as they relate to the overlying skin Surface – study of internal structures as they relate to the overlying skin

Microscopic Anatomy Cytology – study of the cell Cytology – study of the cell Histology – study of tissues Histology – study of tissues

Physiology Considers the operation of specific organ systems Considers the operation of specific organ systems Renal – kidney function Renal – kidney function Neurophysiology – workings of the nervous system Neurophysiology – workings of the nervous system Cardiovascular – operation of the heart and blood vessels Cardiovascular – operation of the heart and blood vessels Focuses on the functions of the body, often at the cellular or molecular level Focuses on the functions of the body, often at the cellular or molecular level

Anatomical Variability Humans vary slightly in both external and internal anatomy Humans vary slightly in both external and internal anatomy Over 90% of all anatomical structures match textbook descriptions, but: Over 90% of all anatomical structures match textbook descriptions, but: Nerves or blood vessels may be somewhat out of place Nerves or blood vessels may be somewhat out of place Small muscles may be missing Small muscles may be missing Extreme anatomical variations are seldom seen Extreme anatomical variations are seldom seen

Chemical level Atoms combine to form molecules Cellular level Cells are made up of molecules Tissue level Tissues consist of similar types of cells 5 Organ system level Organ systems consist of different organs that work together closely Organ level Organs are made up of different types of tissues 6 Organismal level The human organism is made up of many organ systems Atoms Molecules Smooth muscle cell Smooth muscle tissue Connective tissue Smooth muscle tissue Epithelial tissue Blood vessel (organ) Heart Blood vessels Cardiovascular system Levels of Structural Organization Figure 1.1

How Do We Know If It is Alive? Metabolism Metabolism Taking in and digesting food Taking in and digesting food Assimilating digested food Assimilating digested food Respiration Respiration Excretion Excretion Non-living things do not derive energy by taking in or transforming foreign matter. Non-living things do not derive energy by taking in or transforming foreign matter.

Energy utilization

Growth and development

How Do We Know If It is Alive? Growth and Development Growth and Development Organisms develop new parts between or within older parts Organisms develop new parts between or within older parts Non-living things can grow only by addition of material to the outside. Non-living things can grow only by addition of material to the outside.

How Do We Know If It is Alive? Irritability Irritability Response to environmental stimuli Response to environmental stimuli Many forms Many forms May not be proportional to stimulus May not be proportional to stimulus Organism not usually permanently altered by the stimulus Organism not usually permanently altered by the stimulus Non-living things may react to stimuli Non-living things may react to stimuli Always a quantitative relationship between the stimulus and the effect Always a quantitative relationship between the stimulus and the effect

How Do We Know If It is Alive? Reproduction Reproduction Each kind of living thing reproduces itself in kind Each kind of living thing reproduces itself in kind Information needed to develop and reproduce is segregated within the organism Information needed to develop and reproduce is segregated within the organism Information needed to develop and reproduce is passed to offspring Information needed to develop and reproduce is passed to offspring Non-living things do not reproduce Non-living things do not reproduce

Reproduction

How Do We Know If It is Alive? Evolution and Adaptation Evolution and Adaptation Groups of organisms change over time Groups of organisms change over time Changes make organisms more able to live in the particular local environment Changes make organisms more able to live in the particular local environment Non-living things do not change nor adapt to the environment Non-living things do not change nor adapt to the environment

Order

How Do We Know If It is Alive? Order Order All organisms are highly organized All organisms are highly organized Maintain that organization by expending energy Maintain that organization by expending energy Each type usually has definite form and shape Each type usually has definite form and shape All organisms are composed of cells All organisms are composed of cells Non-living things do not maintain their organization by expending energy Non-living things do not maintain their organization by expending energy

Chemical level Atoms combine to form molecules Cellular level Cells are made up of molecules Tissue level Tissues consist of similar types of cells 5 Organ system level Organ systems consist of different organs that work together closely Organ level Organs are made up of different types of tissues 6 Organismal level The human organism is made up of many organ systems Atoms Molecules Smooth muscle cell Smooth muscle tissue Connective tissue Smooth muscle tissue Epithelial tissue Blood vessel (organ) Heart Blood vessels Cardiovascular system Levels of Structural Organization Figure 1.1

Human Survival Needs Nutrients – chemical substances used for energy and cell building Nutrients – chemical substances used for energy and cell building Oxygen – needed for metabolic reactions Oxygen – needed for metabolic reactions Water – provides the necessary environment for chemical reactions Water – provides the necessary environment for chemical reactions Maintaining normal body temperature – necessary for chemical reactions to occur at life-sustaining rates Maintaining normal body temperature – necessary for chemical reactions to occur at life-sustaining rates Atmospheric pressure – required for proper breathing and gas exchange in the lungs Atmospheric pressure – required for proper breathing and gas exchange in the lungs

Homeostasis Homeostasis is the ability to maintain a relatively stable internal environment in an ever-changing outside world Homeostasis is the 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 The internal environment of the body is in a dynamic state of equilibrium Chemical, thermal, and neural factors interact to maintain homeostasis Chemical, thermal, and neural factors interact to maintain homeostasis

Stimulus: Produces change in variable Change detected by receptor Input: Information sent along afferent pathway to 5 Response of effector feeds back to influence magnitude of stimulus and returns variable to homeostasis Variable (in homeostasis) Imbalance Receptor (sensor) Control center 4 Output: Information sent along efferent pathway to Effector Homeostatic Control Mechanisms Figure 1.4

Negative Feedback In negative feedback systems, the output shuts off the original stimulus In negative feedback systems, the output shuts off the original stimulus Example: Regulation of blood glucose levels Example: Regulation of blood glucose levels

Negative Feedback

Positive Feedback In positive feedback systems, the output enhances or exaggerates the original stimulus In positive feedback systems, the output enhances or exaggerates the original stimulus Example: Regulation of blood clotting Example: Regulation of blood clotting Figure 1.6

Anatomical Position Body erect, feet slightly apart, palms facing forward, thumbs point away from body Body erect, feet slightly apart, palms facing forward, thumbs point away from body

Directional Terms Superior and inferior Superior and inferior toward and away from the head, respectively toward and away from the head, respectively Anterior and posterior Anterior and posterior toward the front and back of the body toward the front and back of the body Medial and lateral Medial and lateral toward the midline and away from the midline toward the midline and away from the midline

Directional Terms Proximal and distal Proximal and distal closer to and farther from the origin of the body closer to and farther from the origin of the body Superficial and deep Superficial and deep toward and away from the body surface toward and away from the body surface

Directional Terms

Table 1.1

Body Planes