Chapter 1: An Introduction to the Human Body

complex molecules

The ________ found in foods are broken down so the body can use their parts to assemble the structures and substances needed for life.

higher nitrogen

Your blood has a far ________ gas pressure than the space around you.

ATP

Because they produce ________ constantly, brain cells are susceptible to oxygen deficiency.

**Human anatomy**

is the scientific study of the body’s structures.

**anatomy**

 comes from a Greek root that means “***to cut apart.***”

Macro

means “**large**,” thus, gross anatomy is also referred to as macroscopic anatomy.

Micro

means small

Macro

means "large," thus, gross anatomy is also referred to as macroscopic anatomy.anatomy

In contrast, micro

means "small"

To study the chemical level of organization, scientists consider the simplest building blocks of matter

subatomic particles, atoms and molecules

In 1895, Röntgen made the first durable record of the internal parts of a living human

an "X-ray" image (as it came to be called) of his wifes hand

**Microscopic anatomy**

is the study of structures that can be observed only with the use of a microscope or other magnification devices.

**Regional anatomy**

is the study of the interrelationships of all of the structures in a specific body region, such as the abdomen.

**Systemic anatomy**

is the study of the structures that make up a discrete body system—that is, a group of structures that work together to perform a unique body function.

**Human physiology**

is the scientific study of the chemistry and physics of the structures of the body and the ways in which they work together to support the functions of life.

**Homeostasis**

is the state of steady internal conditions maintained by living things

**Neurophysiology**

is the study of the brain, spinal cord, and nerves and how these work together to perform functions as complex and diverse as vision, movement, and thinking

**cell**

A **__** is the smallest independently functioning unit of a living organism. Even bacteria, which are extremely small, independently-living organisms, have a cellular structure.

**organelles**

A human cell typically consists of flexible membranes that enclose cytoplasm, a water-based cellular fluid together with a variety of tiny functioning units called __

**tissue**

A **__** is a group of many similar cells (though sometimes composed of a few related types) that work together to perform a specific function. 

**organ**

An **___** is an anatomically distinct structure of the body composed of two or more tissue types

**organ system**

An **___** is a group of organs that work together to perform major functions or meet physiological needs of the body.

**organism**

An **___** is a living being that has a cellular structure and that can independently perform all physiologic functions necessary for life.

**Anabolism**

is the process whereby smaller, simpler molecules are combined into larger, more complex substances.

**Catabolism**

is the process by which larger more complex substances are broken down into smaller simpler molecules.

**Human movement**

includes not only actions at the joints of the body, but also the motion of individual organs and even individual cells.

**Development**

is all of the changes the body goes through in life.

**Growth**

is the increase in body size.

**Reproduction**

is the formation of a new organism from parent organisms.

**nutrient**

A **__**is a substance in foods and beverages that is essential to human survival.

**Pressure**

is a force exerted by a substance that is in contact with another substance

**set point**

the physiological value around which the normal range fluctuates.

**normal range**

**i**s the restricted set of values that is optimally healthful and stable.

**Negative feedback**

is a mechanism that reverses a deviation from the set point.

**sensor**

A **__**, also referred to a receptor, is a component of a feedback system that monitors a physiological value.

**control center**

The **__** is the component in a feedback system that compares the value to the normal range.

**effector**

is the component in a feedback system that causes a change to reverse the situation and return the value to the normal range.

**Positive feedback**

intensifies a change in the body’s physiological condition rather than reversing it.

**Anatomical position**

is that of the body standing upright, with the feet at shoulder width and parallel, toes forward.

**Prone**

describes a face-down orientation, and **supine** describes a face up orientation.

**Anterior (or ventral)**

Describes the front or direction toward the front of the body.

**Posterior (or dorsal)**

Describes the back or direction toward the back of the body.

**Superior (or cranial)**

describes a position above or higher than another part of the body proper.

**inferior (or caudal)**

describes a position below or lower than another part of the body proper; near or toward the tail (in humans, the coccyx, or lowest part of the spinal column).

**Lateral**

describes the side or direction toward the side of the body.

**Medial**

describes the middle or direction toward the middle of the body.

**Proximal**

describes a position in a limb that is nearer to the point of attachment or the trunk of the body.

**Distal**

describes a position in a limb that is farther from the point of attachment or the trunk of the body.

**Superficial**

describes a position closer to the surface of the body.

**Deep**

describes a position farther from the surface of the body.

**section**

**i**s a two-dimensional surface of a three-dimensional structure that has been cut.

**plane**

is an imaginary two-dimensional surface that passes through the body.

**sagittal plane**

The **__** is the plane that divides the body or an organ vertically into right and left sides.

**frontal plane**

The **___** is the plane that divides the body or an organ into an anterior (front) portion and a posterior (rear) portion.

**transverse plane**

The__is the plane that divides the body or organ horizontally into upper and lower portions.

**cranial cavity**

houses the brain

**spinal cavity**

(or vertebral cavity) encloses the spinal cord.

**abdominopelvic cavity**

is the largest cavity in the body.

**serous membrane**

A **__** (also referred to a serosa) is one of the thin membranes that cover the walls and organs in the thoracic and abdominopelvic cavities.

**pleura**

is the serous membrane that surrounds the lungs in the pleural cavity.

**pericardium**

is the serous membrane that surrounds the heart in the pericardial cavity

**peritoneum**

is the serous membrane that surrounds several organs in the abdominopelvic cavity.

**Wilhelm Röntgen**

(1845–1923) was experimenting with electrical current when he discovered that a mysterious and invisible “*ray*” would pass through his flesh but leave an outline of his bones on a screen coated with a metal compound.

**X-ray**

is a form of high energy electromagnetic radiation with a short wavelength capable of penetrating solids and ionizing gases.

***Computed tomography (CT)***

is a noninvasive imaging technique that uses computers to analyze several cross-sectional X-rays in order to reveal minute details about structures in the body.

***Magnetic resonance imaging (MRI)***

is a noninvasive medical imaging technique based on a phenomenon of nuclear physics discovered in the 1930s, in which matter exposed to magnetic fields and radio waves was found to emit radio signals.

**Positron emission tomography (PET)**

is a medical imaging technique involving the use of so-called radiopharmaceuticals, substances that emit radiation that is short-lived and therefore relatively safe to administer to the body.

***Ultrasonography***

is an imaging technique that uses the transmission of high-frequency sound waves into the body to generate an echo signal that is converted by a computer into a real-time image of anatomy and physiology.