A&P I - Section 1

What are the six characteristics of living things? Briefly explain each.

1. organization - the specific interrelationships among the parts of an organism and how those parts interact to perform specific functions 2. metabolism - all of the chemical reactions taking place in the cells and internal environment of an organism 3. Responsiveness - an organism's ability to sense changes in its external or internal environment and adjust to those changes. 4. Growth - an increase in the size or number of cells, which produces an overall enlargement of all or part of an organism. 5. Development - changes an organism undergoes through time, beginning with fertilization and ending at death 6. Reproduction - formation of new cells or new organisms.

History of x-rays

Anatomical imaging has made a major contribution to that progress. Anatomical imaging allows medical personnel to look inside the body with amazing accuracy and without the trauma and risk of exploratory surgery. Although most of the technology used in anatomical imaging is very new, the concept and earliest technology are quite old. In 1895, Wilhelm Roentgen (1845-1923) became the first medical scientist to use x-rays to see inside the body. The rays were called x-rays because no one knew what they were.

From simplest to complex, list and define the body's six levels of organization.

1. the chemical - atoms combine to form molecules. 2. cell - molecules form organelles, such as the nucleus, and mitochondria, which make up cells. 3. tissue - similar cells and similar materials make up tissues. 4. organ - different tissues combine to form organs, such as the urinary bladder. 5. organ system - organs, such as the urinary bladder and kidneys, make up an organ system. 6. whole organism levels - organ systems make up an organism.

stimulus

A changed variable is a stimulus because it initiates a homeostatic mechanism.

supine

A person is supine when lying face upward

Tissue level

A tissue is composed of a group of similar cells and the materials surrounding them. The characteristics of the cells and surrounding materials determine the functions of the tissue. The body is made up of four basic tissue types: epithelial, connective, muscle, and nervous.

Why is it important to recognize that humans share many, but not all, characteristics with other animals?

Although much can be learned from studying other organisms, the ultimate answers to questions about humans can be obtained only from humans because other organisms differ from humans in significant ways. A failure to appreciate the differences between humans and other animals led to many misconceptions by early scientists.

Organ level

An organ is composed of two or more tissue types that perform one or more common functions. The urinary bladder, heart, stomach, and lung are examples of organs

Organ system level

An organ system is a group of organs that together perform a common function or set of functions and are therefore viewed as a unit. For example, the urinary system consists of the kidneys, ureter, urinary bladder, and urethra. The kidneys produce urine, which the ureters transport to the urinary bladder, where it is stored until being eliminated from the body through the urethra. In this text, we consider 11 major organ systems: the integumentary, skeletal, muscular, nervous, endocrine, cardiovascular, lymphatic, respiratory, digestive, urinary, and reproductive systems.

Organism level

An organism is any living thing considered as a whole—whether composed of one cell, such as a bacterium, or of trillions of cells, such as a human. The human organism is a network of organ systems, all mutually dependent on one another.

Lateral

"away from the midline." - The nose is in a medial position in the face, and the eyes are lateral to the nose.

distal

"distant" - used to refer to linear structures, such as the limbs, in which one end is near another structure and the other end is farther away. Each limb is attached at its proximal end to the body, and the distal end, such as the hand, is farther away.

Proximal

"nearest" - used to refer to linear structures, such as the limbs, in which one end is near another structure and the other end is farther away. Each limb is attached at its proximal end to the body, and the distal end, such as the hand, is farther away.

Medial

"toward the midline" - The nose is in a medial position in the face, and the eyes are lateral to the nose.

negative-feedback mechanisms have three components

(1) a receptor, which monitors the value of a variable such as body temperature (2) a control center, such as part of the brain, which establishes the set point around which the variable is maintained through communication with the receptors and effectors (3) an effector, such as sweat glands, which can adjust the value of the variable, usually back toward the set point Negative feedback acts to return the variable to its normal range.

example of positive feedback

Birth is another example of a normally occurring positive-feedback mechanism. Near the end of pregnancy, the baby's larger size stretches the uterus. This stretching, especially around the opening of the uterus, stimulates contractions of the uterine muscles. The uterine contractions push the baby against the opening of the uterus and stretch it further. This stimulates additional contractions, which result in additional stretching. This positive-feedback sequence ends only when the baby is delivered from the uterus and the stretching stimulus is eliminated.

set point

Body temperature is a variable that can increase in a hot environment or decrease in a cold one. Homeostatic mechanisms, such as sweating or shivering, normally maintain body temperature near an ideal normal value

Cell level

Cells are the basic structural and functional units of plants and animals. Molecules combine to form organelles (or′gă-nelz; little organs), which are the small structures inside cells. For example, the nucleus is an organelle that contains the cell's hereditary information, and mitochondria are organelles that manufacture adenosine triphosphate (ATP), a molecule cells use for energy. Although cell types differ in their structure and function, they have many characteristics in common. Knowledge of these characteristics, as well as their variations, is essential to understanding anatomy and physiology.

Computed Tomography (CT scans)

Computed tomographic (tō′mō-graf′ik) (CT) scans, developed in 1972 and originally called computerized axial tomographic (CAT) scans, are computer-analyzed x-ray images. A low-intensity x-ray tube is rotated through a 360-degree arc around the patient, and the images are fed into a computer. The computer then constructs the image of a "slice" through the body at the point where the x-ray beam was focused and rotated (a). Some computers are able to take several scans short distances apart and stack the slices to produce a 3-D image of a body part (b).

How does differentiation differ from morphogenesis?

Differentiation involves changes in a cell's structure and function from an immature, generalized state to a mature, specialized state. Morphogenesis is the change in shape of tissues, organs, and the entire organism.

Digital Subtraction Angiography (DSA)

Digital subtraction angiography (an-jē-og′ră-fē) (DSA) is one step beyond CT scanning. A 3-D radiographic image of an organ, such as the brain, is made and stored in a computer. Then a radiopaque dye is injected into the blood, and a second radiographic computer image is made. The first image is subtracted from the second one, greatly enhancing the differences revealed by the injected dye. These dynamic computer images are the most common way angioplasty, is performed. Angioplasty uses a tiny balloon to unclog an artery.

Positron Emission Tomography (PET scans)

Positron emission tomographic (PET) scans can identify the metabolic states of various tissues. This technique is particularly useful in analyzing the brain. When cells are active, they are using energy The energy they need is supplied by the break down of glucose (blood sugar). If radioactively treated ("labeled") glucose is given to a patient, the active cells take up the labeled glucose. As the radioactivity in the glucose decays, positively charged subatomic particles called positrons are emitted. When the positrons collide with electrons, the two particles annihilate each other and gamma rays are given off. The gamma rays can be detected, pinpointing the cells that are metabolically active

negative-feedback

Most systems of the body are regulated by negative-feedback mechanisms, which maintain homeostasis. Negative means that any deviation from the set point is made smaller or is resisted; therefore, in a negative-feedback mechanism, the response to the original stimulus results in deviation from the set point, becoming smaller. An example of important negative-feedback mechanisms in the body are those maintaining normal body temperature. Normal body temperature is critical to our health because it allows molecules and enzymes to keep their normal shape so they can function optimally. An optimal body temperature prevents molecules from being permanently destroyed. Picture the change in appearance of egg whites as they are cooked; the egg whites change from a transparent fluid to a white solid because the heat changes the shape of the egg white molecules. Similarly, if the body is exposed to extreme heat, the shape of the molecules in the body could change, which would eventually prevent them from functioning normally.

lower limb

divided into the thigh, leg, ankle, and foot. The thigh extends from the hip to the knee, and the leg extends from the knee to the ankle.

What are the four basic types of tissues?

epithelial, connective, muscle, and nervous

Cell physiology

examines the processes occurring in cells

Cytology

examines the structural features of cells

histology

examines tissues, which are composed of cells and the materials surrounding them.

Exercise physiology

focuses on the changes in function and structure caused by exercise.

Neurophysiology

focuses on the nervous system

How do variables, set points, and normal ranges relate to homeostasis?

homeostasis is the normal range of a constant environment. a set point is the ideal conditions for achieving homestasis and normal range is the range at which a set point can vary and still be within homoestasis conditions. If the variable goes outside of the normal range it stimulates homeostatic processes to regulate and bring it back to set point.

Anatomical anomalies

physical characteristics that differ from the normal pattern. Anatomical anomalies can vary in severity from relatively harmless to life-threatening. For example, each kidney is normally supplied by one blood vessel, but in some individuals a kidney is supplied by two blood vessels. Either way, the kidney receives adequate blood. On the other hand, in the condition called "blue baby" syndrome, certain blood vessels arising from an infant's heart are not attached in their correct locations; blood is not effectively pumped to the lungs, and so the tissues do not receive adequate oxygen.

back

posterior (dorsal) "that which follows" and "back."

Define the following directional terms and give the term that means the opposite: proximal, lateral, and superficial.

proximal - nearest. Opposite is distal - distant. Lateral - away from the midline. opposite is medial - toward the midline. superficial - a structure close to the surface of the body. opposite - deep - closer to the interior of the body.

What are the three components of a negative-feedback mechanism?

receptor, control center, effector

2. Metabolism

refers to all of the chemical reactions taking place in the cells and internal environment of an organism. It includes an organism's ability to break down food molecules, which the organism uses as a source of energy and raw materials to synthesize its own molecules. Energy is also used when one part of a molecule moves relative to another part, changing the shape of the molecule. In single-celled organisms and certain human cells, this change in molecular shape can cause the whole cell to change shape. Sometimes this change in cell shape can allow the entire organism or cell to move to a different location. Metabolism is necessary for other vital functions, such as responsiveness, growth, development, and reproduction.

4. Growth

refers to an increase in the size or number of cells, which produces an overall enlargement of all or part of an organism. For example, a muscle enlarged by exercise is composed of larger muscle cells than those of an untrained muscle, and the skin of an adult has more cells than the skin of an infant. An increase in the materials surrounding cells can also contribute to growth. For instance, bone grows because of an increase in cell number and the deposition of mineralized materials around the cells.

1. Organization

refers to the specific interrelationships among the parts of an organism and how those parts interact to perform specific functions. Living things are highly organized. All organisms are composed of one or more cells. Some cells in turn are composed of highly specialized organelles, which depend on the precise organization of large molecules. Disruption of this organized state can result in loss of functions, or even death.

Gross anatomy

the study of structures that can be examined without the aid of a microscope, can be approached either systemically or regionally.

etymology

the study of word origins - deviation Most anatomical terms are derived from Latin or Greek. For example, foramen is a Latin word for "hole," and magnum means "large." The foramen magnum is therefore a large hole in the skull through which the spinal cord attaches to the brain.

normal range of values

these mechanisms are not able to maintain body temperature precisely at the set point. Instead, body temperature increases and decreases slightly around the set point

deep

toward the interior of the body. The skin is superficial to muscle and bone.

Right and left

used as directional terms in anatomical terminology.

Anatomical imaging

uses radiographs (x-rays), ultrasound, magnetic resonance imaging (MRI), and other technologies to create pictures of internal structures (table 1.1). Anatomical imaging has revolutionized medical science. Some scientists estimate that the past 20 years have seen as much progress in clinical medicine as occurred in all of medicine's previous history.

prone

when lying face downward.

Give an example of how a negative-feedback mechanism maintains homeostasis.

when the body temperature is raised it sends receptors to the control center to tell it that the body temp is above set point. The control center repsonds by telling the effector to stimulate a sweat gland response.

Magnetic Resonance Imaging (MRI)

Magnetic resonance imaging (MRI) directs radio waves at a person lying inside a large electromagnetic field. The magnetic field causes the protons of various atoms to align (see chapter 2). Because of the large amounts of water in the body, the alignment of hydrogen atom protons is most important in this imaging system. Radio waves of certain frequencies, which change the alignment of the hydrogen atoms, then are directed at the patient. When the radio waves are turned off, the hydrogen atoms realign in accordance with the magnetic field. The time it takes the hydrogen atoms to realign is different for various body tissues. These differences can be analyzed by computer to produce very clear sections through the body. The technique is also very sensitive in detecting some forms of cancer far more readily than can a CT scan.

Give an example of a positive-feedback mechanism that may be harmful to the body and an example of one that is not harmful.

Harmful: inadequate delivery of blood to cardiac (heart) muscle. Contraction of cardiac muscle generates blood pressure and the heart pumps blood to itself through a system of blood vessels on the outside of the heart. Just as with other tissues, blood pressure must be maintained to ensure adequate delivery of blood to the cardiac muscle. Following extreme blood loss, blood pressure decreases to the point that the delivery of blood to cardiac muscle is inadequate. As a result, cardiac muscle does not function normally. The heart pumps less blood, which causes the blood pressure to drop even further—a deviation further from the setpoint. The additional decrease in blood pressure further reduces blood delivery to cardiac muscle, and the heart pumps even less blood, which again decreases the blood pressure. The process self-propagates until the blood pressure is too low to sustain the cardiac muscle, the heart stops beating, and death results. In this example, we see the deviation from the heart rate set point becoming larger and larger—this is a positive-feedback mechanism. Helpful: Birth is another example of a normally occurring positive-feedback mechanism. Near the end of pregnancy, the baby's larger size stretches the uterus. This stretching, especially around the opening of the uterus, stimulates contractions of the uterine muscles. The uterine contractions push the baby against the opening of the uterus and stretch it further. This stimulates additional contractions, which result in additional stretching. This positive-feedback sequence ends only when the baby is delivered from the uterus and the stretching stimulus is eliminated.

Assess your progress

How does the study of anatomy differ from the study of physiology? A-form and structure P-function What is studied in gross anatomy? In surface anatomy? study of structures without microscope. Either regionally or systemically What type of physiology is employed when studying the endocrine system? systemic physiology Why are anatomy and physiology normally studied together? must encompass both anatomy and physiology because structures, functions, and processes are interwoven.

six characteristics of life

Humans are organisms, sharing characteristics with other organisms. The most important common feature of all organisms is life. This text recognizes six essential characteristics of life:

Distinguish between negative feedback and positive feedback.

In negative feedback the receptor monitors the value, the control center establishes the set point and the effector adjusts the value back to set point. In positive feedback the effector stimulates a repsonse that deviates more from the set point in order to over correct the issue. This is meant for positive correction but can lead to harm.

What two directional terms indicate "the back" in humans? What are the opposite terms?

Posterior and dorsal. Opposite in anterior and ventral.

Referring to figure 1.3, which two organ systems are responsible for regulating the other organ systems? Which two are responsible for support and movement?

Regulates the other organ systems: Nervous system and Endocrine system. Responsible for support and movement: support - skeletal movement - muscular

Anatomy and Physiology

Studies of the human body must encompass both anatomy and physiology because structures, functions, and processes are interwoven.

Up

Superior (cephalic) "toward the head"

What two directional terms indicate "toward the head" in humans? What are the opposite terms?

Superipr and cephalic. Opposite are inferior and caudal.

microbiota

The total population of microbial cells on the human body. includes so-called good bacteria, which do not cause disease and may even help us. It also includes pathogenic, or "bad," bacteria.

upper limb

divided into the arm, forearm, wrist, and hand. The arm extends from the shoulder to the elbow, and the forearm extends from the elbow to the wrist.

Homeostasis

The ability of an organism to maintain relatively stable internal conditions while external conditions change.

Six levels of organization of the body

The body can be studied at six levels of organization: the chemical, cell, tissue, organ, organ system, and whole organism levelsical, cell, tissue, organ, organ system, and whole organism levels

Anatomy

The study of the form and structure of the human body.

Physiology

The study of the function of the human body.

the abdomen is sometimes sub-divided into regions by four imaginary lines: two horizontal and two vertical.

These four lines create a "virtual" tic-tac-toe grid on the abdomen, resulting in nine regions: epigastric, right and left hypochondriac, umbilical, right and left lumbar, hypogastric, and right and left iliac

X-ray (radiograph)

This extremely shortwave electromagnetic radiation (see chapter 2) moves through the body, exposing a photographic plate to form a radiograph (rā′dē-ō-graf). Bones and radiopaque dyes absorb the rays and create underexposed areas that appear white on the photographic film. Many of us have had an X-ray, either to visualize a broken bone or at the dentist. However, a major limitation of radiographs is that they give only flat, two-dimensional (2-D) images of the body.

Ultrasound

Ultrasound, the second oldest imaging technique, was first developed in the early 1950s from World War II sonar technology. It uses high-frequency sound waves, which are emitted from a transmitter-receiver placed on the skin over the area to be scanned. The sound waves strike internal organs and bounce back to a receiver on the skin. Even though the basic technology is fairly old, The most important advances in this field occurred only after it became possible to analyze the reflected sound waves by when a computer could be used to analyze the pattern of reflected sound waves and transfer. Once a computer analyzes the pattern of sound waves, the information is transferred to a monitor to be visualized as a sonogram (son′ō-gram) image. One of the more recent advances in ultrasound technology is the ability of more advanced computers to analyze changes in position through "real-time" movements. Among other medical applications, ultrasound is commonly used to evaluate the condition of the fetus during pregnancy.

Superficial

describes a structure close to the surface of the body. The skin is superficial to muscle and bone.

X-ray risks

Whenever the human body is exposed to x-rays, ultrasound, electromagnetic fields, or radioactively labeled substances, a potential risk exists. This risk must be weighed against the medical benefit. Numerous studies have been conducted and are still being done to determine the effects of diagnostic and therapeutic exposure to x-rays. The risk of anatomical imaging is minimized by using the lowest possible doses providing the necessary information. No known risks exist from ultrasound or electromagnetic fields at the levels used for diagnosis. Both surface anatomy and anatomical imaging provide important information for diagnosing disease.

System

a group of structures that have one or more common functions, such as the cardiovascular, nervous, respiratory, skeletal, or muscular systems. In systemic anatomy, the body is studied system by system. In regional anatomy, the body is studied area by area. Within each region, such as the head, abdomen, or arm, all systems are studied simultaneously. The regional approach is taken in most graduate programs at medical and dental schools. The systemic approach is used in this and most other introductory textbooks.

Anatomical position

a person standing erect with the face directed forward, the upper limbs hanging to the sides, and the palms of the hands facing forward

Embryology

a subspecialty of developmental anatomy, considers changes from conception to the end of the eighth week of development.

3. Responsiveness

an organism's ability to sense changes in its external or internal environment and adjust to those changes. Responses include actions such as moving toward food or water and moving away from danger or poor environmental conditions. Organisms can also make adjustments that maintain their internal environment. For example, if the external environment causes the body temperature to rise, sweat glands produce sweat, which can lower body temperature down to the normal range.

front

anterior (ventral) "that which goes before" and "belly"

Prefixes and suffixes

can be added to words to expand their meaning. For example, the suffix -itis means an inflammation, so appendicitis is an inflammation of the appendix.

trunk

can be divided into the thorax, abdomen, and pelvis.

systemic physiology

considers the functions of organ systems

central region of the body

consists of the head, neck, and trunk.

abdomen

contains organs such as the liver, stomach, and intestines.

pelvis

contains the bladder and reproductive organs.

cardiovascular physiology

deals with the heart and blood vessels.

5. Development

includes the changes an organism undergoes through time, beginning with fertilization and ending at death. The greatest developmental changes occur before birth, but many changes continue after birth, and some go on throughout life. Development usually involves growth, but it also involves differentiation and morphogenesis. Differentiation involves changes in a cell's structure and function from an immature, generalized state to a mature, specialized state. For example, following fertilization, immature cells differentiate to become specific cell types, such as skin, bone, muscle, or nerve cells. These differentiated cells form tissues and organs. Morphogenesis (mōr-fō-jen′ĕ-sis) is the change in shape of tissues, organs, and the entire organism.

down

inferior (caudal) "toward the tail"

Chemical level

involves interactions between atoms, which are tiny building blocks of matter. Atoms combine to form molecules, such as water, sugar, lipids, and proteins. The function of a molecule is intimately related to its structure. For example, collagen molecules are ropelike protein fibers that give skin structural strength and flexibility. With old age, the structure of collagen changes, and the skin becomes fragile and more easily torn. We present a brief overview of chemistry in chapter 2.

Surface anatomy

involves looking at the exterior of the body to visualize structures deeper inside the body. For example, the sternum (breastbone) and parts of the ribs can be seen and palpated (felt) on the front of the chest. Health professionals use these structures as anatomical landmarks to identify regions of the heart and points on the chest where certain heart sounds can best be heard.

Positive-feedback

mechanisms occur when a response to the original stimulus results in the deviation from the set point becoming even greater. At times, this type of response is required to re-achieve homeostasis. For example, during blood loss, a chemical responsible for blood clot formation, called thrombin, stimulates production of even more thrombin (figure 1.8). In this way, a disruption in homeostasis is resolved through a positive-feedback mechanism.

The abdomen is often subdivided superficially into quadrants by two imaginary lines

one horizontal and one vertical—that intersect at the navel. The quadrants formed are the right-upper, left-upper, right-lower, and left-lower quadrants.

Developmental Anatomy

studies the structural changes that occur between conception and adulthood.

What is anatomical position in humans? Why is it important?

the anterior part of the body is facing forward with the arms down and palms facing forward. It is used in scientific reference.

thorax

the chest cavity where the heart and lungs are located.

microbiome

the combination of these microbial cells and their genes (the microbiota)

Homeostasis

the existence and maintenance of a relatively constant environment within the body. To achieve homeostasis, the body must actively regulate conditions that are constantly changing. As our bodies undergo their everyday processes, we are continuously exposed to new conditions. These conditions are called variables because their values can change. For example, a small amount of fluid surrounds each body cell; for cells to function normally, the volume, temperature, and chemical content of this fluid must be maintained within a narrow range.

6. Reproduction

the formation of new cells or new organisms. Without reproduction of cells, growth and development are not possible. Without reproduction of organisms, species become extinct.

Use as many directional terms as you can to describe the relationship between your kneecap and your heel.

the kneecap is ventral (anterior) to the heel. the heel is dorsal (posterior) to the kneecap. The kneecap is proximal to the heel. The heel is distal to the kneecap. The heel is inferior (caudal) to the kneecap. The kneecap is superior (cephalic) to the heel.

Pathology

the medical science dealing with all aspects of disease, with an emphasis on the cause and development of abnormal conditions, as well as the structural and functional changes resulting from disease.

normal body temp range

the normal body temperature range is no more than 1 degree Fahrenheit above or below normal. Our average body temperature is 98.6 degrees Fahrenheit.

Anatomy

the scientific discipline that investigates the body's structures.Examines the relationship between the structure of a body part and it's function.

Physiology

the scientific investigation of the processes or functions of living things. The major goals when studying human physiology are to understand and predict the body's responses to stimuli and to understand how the body maintains conditions within a narrow range of values in a constantly changing environment. Physiology often examines systems rather than regions because a particular function can involve portions of a system in more than one region.