Chapter 1: The Human Body - An Orientation

Comprehensive question and answer review flashcards covering essential concepts, anatomical terminology, body cavities, control mechanisms, and organizational hierarchy from Chapter 1.

What is the literal Greek definition and meaning of the term anatomy?

Anatomy comes from the Greek meaning "to cut apart" and is the study of the form or structure of body parts and how these parts relate to one another.

How is physiology defined in relation to the human body?

Physiology is the study of the functioning of the body's structural machinery—how the parts of the body work and carry out their life-sustaining activities as dynamic processes.

What are the two main subdivisions of microscopic anatomy?

Cytology (the study of the cells of the body) and histology (the study of the tissues of the body).

What is the distinction between regional anatomy and systemic anatomy?

In regional anatomy, all structures in one part of the body are studied at the same time, whereas in systemic anatomy, various systems of the body are studied.

What are the focus areas of embryology, pathology, and molecular biology in anatomy?

Embryology focuses on developmental changes occurring before birth, pathology focuses on disease-related changes, and molecular biology focuses on the subcellular level.

What does the essential concept "complementarity of structure and function" state?

Function always reflects structure; what a structure can do depends on its specific form.

What are the levels of structural organization in the human body from simplest to most complex?

Atoms, molecules, organelles, cells, tissues, organs, organ systems, and organism.

How is homeostasis defined?

The ability to maintain relatively stable internal conditions despite a changing external environment, representing a dynamic state of equilibrium or balance.

What are the eight functional characteristics required for maintaining human life?

1. Maintenance of boundaries, 2. Movement, 3. Responsiveness, 4. Digestion, 5. Metabolism, 6. Excretion, 7. Reproduction, and 8. Growth.

What proportion of air is made up of oxygen, and why is oxygen essential to survival?

Oxygen makes up $20\%$ of the air we breathe and is required for oxidative chemical reactions that release energy from food.

What percentage of body weight is water, and what functions does it serve?

Water accounts for $60\text{--}80\%$ of body weight, providing a liquid environment for chemical reactions and a fluid base for body secretions and excretions.

What is normal body temperature, and what happens when it shifts too low or too high?

Body temperature must be maintained around $37\,^\circ\text{C}$ ($98.6\,^\circ\text{F}$). A decreased temperature slows physiological reactions, while an increased temperature causes chemical reactions to proceed too rapidly and denatures body proteins.

What are the three interdependent components of all homeostatic control mechanisms?

1. Control Center (determines set point, analyzes input, determines response), 2. Receptor (monitors environment, sends input via afferent pathway), and 3. Effector (provides response via efferent pathway).

How does a negative feedback mechanism operate, and what is its main goal?

The output of the system feeds back and decreases or reduces the original stimulus; its overall goal is the prevention of sudden severe changes within the body.

How does a positive feedback mechanism work, and what are two specific examples?

The response enhances or accelerates the original stimulus in the same direction as the initial disturbance; examples include blood coagulation and labor contractions involving oxytocin.

How is the body positioned in standard anatomical position?

The body is erect with feet together and palms facing forward, with the thumbs pointing away from the body.

What do the directional terms cephalad/caudal and dorsal/ventral indicate?

Cephalad means toward the head and caudal means toward the tail (interchangeable with superior/inferior); dorsal means backside and ventral means belly side (interchangeable with posterior/anterior).

What is the difference between proximal and distal?

Proximal means nearer to the trunk or point of attachment, whereas distal means farther from the trunk or point of attachment.

What structures comprise the axial and appendicular divisions of the body?

The axial part makes up the main axis of the body (head, neck, and trunk); the appendicular part consists of the appendages or limbs.

How do sagittal, midsagittal, and parasagittal planes divide the body?

A sagittal plane runs longitudinally to divide the body into right and left portions; a midsagittal (median) plane is exactly midline creating equal halves; a parasagittal plane includes all other sagittal planes off the midline.

How do frontal and transverse planes divide the body?

A frontal plane runs longitudinally to divide the body into anterior and posterior parts; a transverse plane runs horizontally at a right angle to the long axis to divide the body into superior and inferior parts.

What cavities compose the dorsal body cavity, and what organs do they house?

The cranial cavity and the vertebral (or spinal) cavity, which are continuous with each other and house the brain and spinal cord.

What are the two major lateral and medial subdivisions of the thoracic cavity?

The lateral pleural cavities (each containing a lung) and the medial mediastinum (containing the heart, esophagus, trachea, and other thoracic organs).

What organs are found within the abdominal and pelvic cavities?

The abdominal cavity contains the stomach, intestines, spleen, liver, and other organs; the pelvic cavity contains the bladder, some reproductive organs, and the rectum.

What is the difference between parietal serosa and visceral serosa?

Parietal serosa lines the body cavity walls ("parie" = wall), whereas visceral serosa folds on itself to cover the organs inside the cavity ("viscus" = organ in a body cavity).

What are the specific names of the parietal and visceral serous membranes covering the heart and lungs?

For the heart: parietal pericardium and visceral pericardium; for the lungs: parietal pleura and visceral pleura.

What causes pleurisy and what symptom does it produce?

Pleurisy is caused by inflammation of serous membranes accompanied by a deficit of lubricating serous fluid, causing excruciating pain as organs stick together.