Seeley's Essentials of Anatomy & Physiology - Chapter 1: The Human Organism

Vocabulary flashcards covering basic concepts of anatomy and physiology, levels of organization, homeostatic feedback loops, directional terms, body planes, cavities, and serous membranes.

Anatomy

The study of internal and external body structures, including where structures are located, what they are made of, and their physical relationships; literally means "to dissect; a cutting open".

Physiology

The study of the processes and functions of anatomical structures, including how the parts of the human organism work and their interrelationships.

Cell

The basic unit of life, containing compartments and organelles such as the mitochondria and nucleus.

Tissue

A group of cells with similar structure and function, along with the extracellular substances they release.

Organ

A structure composed of two or more tissue types acting together to perform specific functions.

Organ-System

A group of organs contributing to a vital life function in the body.

Organism

A complete living entity made up of all organ systems working together to maintain homeostasis, including associated microorganisms such as intestinal bacteria.

Metabolism

The sum of all chemical and physical reactions needed to sustain an organism, including acquiring and using energy from food and eliminating waste products.

Responsiveness

The ability of an organism to sense and respond to changes in its internal or external environment.

Differentiation

The process during development where cell structure and function change from generalized to specialized.

Homeostasis

The maintenance of a relatively stable internal environment despite fluctuations in the external or internal environment.

Variable

A measure of a body property that may change in value, such as body temperature, heart rate, blood pressure, or blood glucose levels.

Set point

The normal or average value of a physiological variable.

Normal range

The normal extent of increase or decrease of a variable around its set point.

Receptor

A component of a feedback loop that detects changes in a variable and receives a stimulus.

Control center

A component of a feedback loop that receives receptor signals, establishes the set point for a variable, and sends signals to an effector.

Effector

A component of a feedback loop that directly causes a change in a physiological variable.

Negative feedback

The primary mechanism of homeostatic regulation, involving the detection of deviation away from a set point and correction by reversal toward the set point.

Positive feedback

A mechanism occurring when an initial stimulus further stimulates the response, causing progressive deviation away from the set point outside the normal range.

Anatomical Position

The standard reference position where a person stands erect with face and palms facing forward.

Superior

Anatomical direction meaning above (also referred to as cephalic or cranial).

Inferior

Anatomical direction meaning below (also referred to as caudal).

Anterior

Anatomical direction meaning toward the front of the body (also referred to as ventral).

Posterior

Anatomical direction meaning toward the back of the body (also referred to as dorsal).

Medial

Anatomical direction meaning close to the midline of the body.

Lateral

Anatomical direction meaning away from the midline of the body.

Proximal

Anatomical direction meaning close to the point of attachment.

Distal

Anatomical direction meaning far from the point of attachment.

Superficial

Anatomical direction describing a structure close to the surface of the body.

Deep

Anatomical direction describing a structure toward the interior of the body.

Sagittal plane

A body plane that separates the body into right and left parts.

Median plane

A mid-sagittal plane that divides the body into equal left and right halves.

Transverse plane

A horizontal plane that separates the body into superior and inferior parts, producing a cross section.

Frontal plane

A vertical plane that separates the body into anterior and posterior parts.

Dorsal body cavity

The body cavity that encloses the organs of the nervous system, including the cranial cavity and vertebral canal.

Ventral body cavity

The body cavity containing the majority of internal organs (viscera), divided into the thoracic cavity and abdominopelvic cavity.

Mediastinum

The space between the lungs within the thoracic cavity that contains the heart, major blood vessels, thymus gland, esophagus, and trachea.

Visceral membrane

The inner layer of a serous membrane that connects directly to and covers internal organs.

Parietal membrane

The outer layer of a serous membrane that anchors organs to the trunk wall.

Pericardium

The serous membrane surrounding the heart, consisting of a visceral layer and a parietal layer surrounding the pericardial cavity.

Pleura

The serous membrane surrounding the lungs and lining the inner wall of the thorax.

Peritoneum

The serous membrane covering organs in the abdomen and pelvis and lining the inner wall of the abdominopelvic cavity.

Mesenteries

Double layers of visceral peritoneum that hold abdominal organs together and anchor them.