1. Define Anatomy & Physiology.
Anatomy is the science of structure and the relationships among structures.
Physiology is the science of body functions, that is, how the body parts work. Because function can never be separated completely from structure, we can understand the human
body best by studying anatomy and physiology together.
2. Describe the structural organization of the human body.
The structures of the human body are organized into several
levels, similar to the way letters of the alphabet, words, sentences,
paragraphs, and so on are organized. Listed here,
from smallest to largest, are the six levels of organization of
the human body: chemical, cellular, tissue, organ, system, and
organismal
3. Outline the body systems and explain how they relate to one another.
The chemical level includes atoms, the smallest units of
matter that participate in chemical reactions, and
molecules, two or more atoms joined together. Atoms and
molecules can be compared to letters of the alphabet. Certain
atoms, such as carbon (C), hydrogen (H), oxygen (O),
nitrogen (N), phosphorus (P), and others, are essential for
maintaining life. Familiar examples of molecules found in
the body are DNA (deoxyribonucleic acid), the genetic
material passed on from one generation to another; hemoglobin,
which carries oxygen in the blood; glucose, commonly
known as blood sugar; and vitamins, which are
needed for a variety of chemical processes. Chapters 2 and
20 focus on the chemical level of organization.
Molecules combine to form structures at the next level of
organization—the cellular level. Cells are the basic structural
and functional units of an organism. Just as words
are the smallest elements of language, cells are the smallest
living units in the human body. Among the many
types of cells in your body are muscle cells, nerve cells,
and blood cells. Figure 1.1 shows a smooth muscle cell,
one of three different kinds of muscle cells in your body.
As you will see in Chapter 3, cells contain specialized
structures called organelles, such as the nucleus, mitochondria,
and lysosomes, that perform specific functions.
The tissue level is the next level of structural organization.
Tissues are groups of cells and the materials surrounding
them that work together to perform a particular function.
Cells join together to form tissues similar to the way words
are put together to form sentences. The four basic types of
tissue in your body are epithelial tissue, connective tissue, muscular
tissue, and nervous tissue. The similarities and differences
among the different types of tissues are the focus of
Chapter 4. Note in Figure 1.1 that smooth muscle tissue
consists of tightly packed smooth muscle cells.
At the organ level, different kinds of tissues join together
to form body structures. Organs usually have a recognizable
shape, are composed of two or more different types
of tissues, and have specific functions. Tissues join together
to form organs similar to the way sentences are
put together to form paragraphs. Examples of organs are
the stomach, heart, liver, lungs, and brain. Figure 1.1
shows several tissues that make up the stomach. The
serous membrane is a layer around the outside of the stomach
that protects it and reduces friction when the stomach
moves and rubs against other organs. Underneath
the serous membrane are the smooth muscle tissue layers,
which contract to churn and mix food and push it on to
the next digestive organ, the small intestine. The innermost
lining of the stomach is an epithelial tissue layer,
which contributes fluid and chemicals that aid digestion.
The next level of structural organization in the body is the
system level. A system consists of related organs that have
a common function. Organs join together to form systems
similar to the way paragraphs are put together to form
chapters. The example shown in Figure 1.1 is the digestive
system, which breaks down and absorbs molecules in food.
In the chapters that follow, we will explore the anatomy
and physiology of each of the body systems. Table 1.1
introduces the components and functions of these systems.
As you study the body systems, you will discover how they
work together to maintain health, protect you from disease,
and allow for reproduction of the species.
The organismal level is the largest level of organization.
All of the systems of the body combine to make up an
organism (OR-ga-nizm), that is, one human being. Systems
join together to form an organism similar to the
way chapters are put together to form a book.
Week One Outline
Chapters 1, 2, and 22
Chapter One – Organization of the Human Body
A. ANATOMY AND PHYSIOLOGY DEFINED
1. Define ANATOMY as the science of structure and the relationships among structures.
2. Define PHYSIOLOGY as the science of body functions, that is, how the body parts function, and emphasize that the structure of a part determines how it will function.
B. LEVELS OF ORGANIZATION
1. The CHEMICAL LEVEL includes atoms, the smallest units of matter that participate in chemical reactions, and molecules, two or more atoms joined together.
2. Molecules combine to form the CELLULAR LEVEL. Cells are the basic structural and functional units of an organism, and the smallest living units in the human body.
3. Groups of cells and material surrounding them that work together to perform a particular function represents the TISSUE LEVEL OF ORGANIZATION. Four basic tissue types represent this level: epithelial tissue, connective tissue, muscle tissue, and nervous tissue.
4. When different types of tissue join together they form the ORGAN LEVEL. These structures are composed of two or more different tissues, and have specific functions.
5. The grouping of related organs that have a common function forms the SYSTEM LEVEL.
6. The largest level of organization is the ORGANISMAL LEVEL, which includes all systems of the body that combine to form the ORGANISM.
C. HOW BODY SYSTEMS WORK TOGETHER
1. The body systems work together to maintain health, protect one from disease, and allow for the reproduction of the species.
2. The integumentary system, for example, protects all systems by serving as a barrier between the outside environment and internal tissues and organs.
3. The cardiovascular system carries nutrients to and wastes away from the cells. As well as regulating acidity, temperature, and water content of the body fluids.
D. LIFE PROCESSES
1. METABOLISM is the sum of all chemical reactions in the body. It includes the breakdown of large complex molecules into smaller, simpler ones and the building of the body’s structural and functional components.
2. RESPONSIVENESS is the body’s ability to detect and respond to changes in the internal or external environment.
3. MOVEMENT includes motion of the whole body, individual organs, single cells, or even structures within cells.
4. GROWTH refers to the increase in body size due to an increase in size of existing cells, the number of cells, or the amount of material surrounding cells.
5. DIFFERENTIATION is the process whereby unspecialized cells become specialized cells.
6. REPRODUCTION refers to the formation of new cells for growth, repair, or replacement, or the production of a new individual.
E. HOMEOSTASIS: MAINTAINING LIMITS
1. HOMEOSTASIS ensures that the body’s internal environment remains steady despite changes inside and outside the body. All body systems attempt to maintain homeostasis.
2. Homeostasis is controlled mainly by the nervous and endocrine systems.
3. Any disruption that causes a change in a controlled condition is called stimulus.
4. Homeostasis is maintained by means of feedback mechanisms.
5. The components of a feedback system are a CONTROL CENTER, a RECEPTOR, and an EFFECTOR.
6. A negative feedback system reverses a change in a controlled condition in order to maintain homeostasis. Most feedback systems in the body are negative.
7. A positive feedback system reinforces the initial change in the controlled condition. If positive feedback should occur, its results are usually destructive or deadly. However, a few are beneficial such as contractions in childbirth, ovulation, and blood clotting.
F. HOMEOSTASIS OF BLOOD PRESSURE (BP)
1. BLOOD PRESSURE is the force of blood as it passes through the vessels. In order to sustain life it must be maintained at an appropriate pressure.
2. Blood pressure depends on the rate and strength of the heartbeat. If the heart beats faster, more blood pushes into the arteries and elevates the pressure.
3. Increased pressure is detected by baroreceptors, pressure-sensitive nerve cells located in the walls of certain blood vessels. These respond by sending impulses to the brain.
4. The brain, in response, sends nerve impulses to the heart and certain blood vessels to slow the rate, thus decreasing pressure.
5. This cycle is called a FEEDBACK SYSTEM.
6. A FEEDBACK SYSTEM involves a cycle of events in which the information about body conditions is continually monitored and fed back to a central control region.
G. AGING AND HOMEOSTASIS
1. Aging is a normal process characterized by a progressive decline in the body’s ability to restore homeostasis.
2. The changes associated with aging are apparent in all body systems.
H. ANATOMICAL TERMS
1. Directional terms are always given in regard to the body in ANATOMICAL POSITION.
2. In anatomical position, the subject stands erect facing the observer, with the head level and the eyes facing forward. The feet are flat on the floor and directed forward and the arms are at the sides with palms turned forward.
3. DIRECTIONAL TERMS are used to describe the position of one body part to another.
4. Commonly used terms include but are not limited to:
• SUPERIOR—towards the head, or the upper part of a structure
• INFERIOR—towards the feet, or the lower part of a structure
• ANTERIOR/VENTRAL—nearer to or at the front of the body
• POSTERIOR/DORSAL—nearer to or at the back of the body
• MEDIAL—nearer to the midline or midsagittal plane
• LATERAL—farther from the body midline or midsagittal plane
• INTERMEDIATE—between two structures
• PROXIMAL—nearer to the attachment of a limb to the trunk
• DISTAL—farther from the attachment of a limb to the trunk
• SUPERFICIAL—toward or on the body surface
• DEEP—away from the surface of the body
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